TWI581063B - And a photoresist pattern forming method for a radiation-sensitive linear resin composition for liquid immersion exposure - Google Patents

Description

Radiation-sensitive resin composition for liquid immersion exposure and method for forming photoresist pattern

The present invention relates to a radiation sensitive resin composition for liquid immersion exposure and a photoresist pattern forming method.

The radiation-sensitive resin composition for microfabrication used in the production of an integrated circuit device or the like is produced by irradiating an exposure portion with, for example, ArF excimer laser light, and reacting with the acid as a catalyst to expose A difference in solubility between the portion and the unexposed portion to the alkali developing solution is formed to form a photoresist pattern.

In recent years, the liquid immersion exposure method has been expanded as a method of forming a finer photoresist pattern having a line width of about 45 nm. The liquid immersion exposure method has an advantage that it is difficult to reduce the depth of focus even when the numerical aperture (NA) of the lens is increased, and high resolution is obtained. The radiation-sensitive resin composition used in the liquid immersion exposure method is required to prevent the coating film from deteriorating or the contamination of the lens or the like by suppressing the acid immersion film from being dried by the liquid immersion exposure liquid such as an acid generator. The surface of the resist film is dehydrated to prevent water marks, and the exposure can be scanned at high speed.

The means to achieve this have been proposed to be formed on the photoresist film. A technique of a film (protective film) (refer to Japanese Laid-Open Patent Publication No. 2005-352384), but this technique requires an additional film forming step, which is complicated. On the other hand, a radiation-sensitive resin composition containing a fluorine-containing atomic polymer having a high hydrophobicity and having a technique of improving the hydrophobicity of the surface of the photoresist film is known (refer to International Publication No. 2007/116664).

On the other hand, when the hydrophobicity of the surface of the photoresist film is increased, the surface wettability of the developer liquid or the cleaning liquid is lowered, so that the exposed portion of the photoresist film is developed or the image residue deposited on the surface of the unexposed portion is formed. The tendency to use the washing to remove is insufficient. As a result, in the photoresist pattern, a bridge defect in which one of the patterns is connected to each other, or an abnormality in the image defect such as a spot defect caused by the adhesion of the developer residue may occur. For the purpose of suppressing such development defects, a technique of using a polymer containing a trifluoromethyl alcohol group-containing alkyl ester of (meth)acrylic acid has been proposed (see JP-A-2010-176037). According to this technique, the contact angle of the surface of the photoresist film with respect to the liquid such as water can be increased at the time of liquid immersion exposure, and becomes low at the time of development, and as a result, high-speed scanning exposure can be achieved at the same time, and generation of defects can be reduced.

However, the degree of decrease in the back contact angle of the above-mentioned conventional radiation-sensitive resin composition after development is not sufficient, or the occurrence of development defects cannot be sufficiently suppressed. On the other hand, it is also required to further increase the back contact angle during immersion exposure, further increase the scanning exposure, and improve the productivity of the immersion exposure process.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] JP-A-2005-352384

[Patent Document 2] International Publication No. 2007/116664

[Patent Document 3] JP-A-2010-176037

The present invention has been made in view of the above problems, and an object thereof is to provide a structure in which a back contact angle of a photoresist film surface becomes large at the time of liquid immersion exposure, becomes small after development, and can suppress development defects. The resultant immersion exposure radiation sensitive resin composition.

The invention for solving the above-mentioned problems is a radiation-sensitive resin composition for liquid immersion exposure containing [A] having a structural unit represented by the following formula (1) (hereinafter also referred to as "structural unit (I)") Polymer (hereinafter also referred to as "[A] polymer"), and [B] sensitizing radioactive acid generator (hereinafter also referred to as "[B] acid generator"),

(In the formula (1), R ¹ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, R ² is a single bond, a divalent chain hydrocarbon group having 1 to 20 carbon atoms, and a divalent carbon number of 3 to 20 An alicyclic hydrocarbon group, or a combination of one or more of these and -O-, R ³ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, and R ^A is a hydrogen atom or a carbon number of 1~ 20 one-price organic base).

The radiation sensitive linear resin composition for liquid immersion exposure of the present invention can make the receding contact angle of the photoresist film larger during liquid immersion exposure by containing the [A] polymer and the [B] acid generator, after development It becomes smaller and can suppress the occurrence of development defects. The reason why the radiation-sensitive resin composition for liquid immersion exposure has the above-described configuration and exhibits the above-described effects is not clear, but it is presumed to be as follows, for example. That is, the [A] polymer has a group represented by -C(R ¹ )(OR ^A )(CF ₃ ) (hereinafter also referred to as "base (a)") having a fluorine atom and contributing to [A] High hydrophobicity of the polymer. On the other hand, the group (a) is ionized by the action of an alkali developing solution to impart hydrophobicity to the [A] polymer. Further, in the structural unit (I), the group (a) has the above specific position different from the -COOR ³ group. Due to the specific molecular structure, it is considered that the hydrophobicity and hydrophilicity can be effectively exhibited. As a result, the surface of the photoresist film formed by the immersion-sensitive radiation-sensitive resin composition can be made to have a receding contact angle in the liquid. The immersion exposure is higher than in the past and can be greatly reduced after development. Further, after the development, by making the receding contact angle smaller, the developing liquid and the washing liquid can be brought into better contact with the surface of the resist film, and as a result, the occurrence of development defects can be effectively suppressed.

The radiation sensitive linear resin composition for immersion exposure further contains [C] a polymer having a fluorine atom content ratio smaller than that of [A] polymer (hereinafter also referred to as "[C] polymer"), and the [C] polymerization The material preferably has an acid dissociable group.

The radiation sensitive linear resin composition for liquid immersion exposure usually contains a [C] polymer as a base polymer in addition to the [A] polymer and the [B] acid generator. By making the fluorine atom content of the [A] polymer higher than the [C] polymer, the [A] polymer can be effectively biased to the surface of the photoresist film, and as a result, the surface of the photoresist film can be increased. The receding contact angle changes. According to this, according to the radiation-sensitive resin composition for liquid immersion exposure, the receding contact angle of the photoresist film can be made larger at the time of liquid immersion exposure, smaller after development, and the occurrence of development defects can be further suppressed.

The [A] polymer preferably further has a structural unit containing an acid-dissociable group (hereinafter also referred to as "structural unit (II)"). By further having the structural unit (II) of the [A] polymer, the dissolution of the [A] polymer in the exposed portion against the developing solution can be further suppressed. As a result, the radiation sensitive linear resin composition for immersion exposure can further suppress the occurrence of development defects.

The radiation sensitive linear resin composition for immersion exposure preferably further contains a [D] acid diffusion control body. The radiation sensitive linear resin composition for immersion exposure can be maintained while further containing a [D] acid diffusion control body The characteristics of the receding contact angle and the like are improved while the lithography characteristics such as resolution are improved.

The radiation sensitive resin composition of the present invention contains [A] a polymer having a structural unit represented by the following formula (1), [B] a radioactive acid generator, and [C] a fluorine atom content ratio [A] a polymer having a small polymer, and the [C] polymer has an acid dissociable group,

(In the formula (1), R ¹ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, R ² is a single bond, a divalent chain hydrocarbon group having 1 to 20 carbon atoms, and a divalent carbon number of 3 to 20 An alicyclic hydrocarbon group, or a combination of one or more of these and -O-, R ³ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, and R ^A is a hydrogen atom or a carbon number of 1~ 20 one-price organic base).

According to the radiation-sensitive linear resin composition, the surface of the photoresist film can be made to have a larger back contact angle, become smaller after development, and can suppress the occurrence of development defects.

The photoresist pattern forming method of the present invention has the following steps: a step of forming a photoresist film by using the radiation-sensitive resin composition for immersion exposure, and a step of immersing the liquid for immersion exposure to immerse the photoresist film And a step of developing the photoresist film exposed by the above liquid immersion.

According to the photoresist pattern forming method, since the radiation sensitive resin composition for liquid immersion exposure is used, it is possible to increase the speed of scanning exposure and form a photoresist pattern having less development defects.

Here, the "organic group" means a group containing at least one carbon atom.

As described above, according to the radiation-sensitive resin composition for immersion exposure and the method for forming a photoresist pattern of the present invention, it is possible to realize high-speed scanning exposure and form a photoresist pattern having less development defects. Accordingly, the present invention can be applied to a liquid immersion exposure process, and an improvement in productivity and an improvement in the quality of the formed photoresist pattern can be achieved.

<The radiation sensitive resin composition for liquid immersion exposure>

The radiation sensitive linear resin composition for liquid immersion exposure contains [A] polymer and [B] acid generator. The radiation sensitive linear resin composition for liquid immersion exposure also contains a [C] polymer, a [D] acid diffusion control body, and an [E] solvent as preferred components, and may also contain a range which does not impair the effects of the present invention. Any other ingredients. The components are described below.

<[A] Polymer>

[A] The polymer is a polymer having a structural unit (I). [A] The polymer system functions as a surface hydrophobized polymer. The "surface hydrophobized polymer" means a polymer having an auxiliary component which tends to be biased on the surface layer of the formed photoresist film by being contained in the radiation sensitive resin composition for liquid immersion exposure. The [A] polymer can be biased to the surface layer when the photoresist film is formed, and the surface layer of the photoresist film is hydrophobized. As a result, high-speed scanning or the like in the immersion exposure can be made possible.

From the viewpoint of improving the function as the surface hydrophobized polymer, the fluorine atom content of the [A] polymer is preferably higher than the fluorine atom content of the base polymer. The base polymer is exemplified by a [C] polymer or the like which will be described later. The fluorine atom content of the polymer [A] is preferably 5% by mass or more, more preferably 7% by mass or more, and still more preferably 10% by mass or more. The fluorine atom content (% by mass) of the polymer can be calculated from the structure obtained by analyzing the structure of the polymer by ¹³ C-NMR.

[A] The polymer preferably has a structural unit (II) having an acid-dissociable group in addition to the structural unit (I), and may have a structural unit (III) containing a fluorine atom, or may have a structural unit (I). Other structural units other than ~(III). The [A] polymer may have one or two or more of these structural units. Hereinafter, each structural unit will be described.

[structural unit (I)]

The structural unit (I) is a structural unit represented by the above formula (1). The immersion exposure is carried out by making the [A] polymer have a structural unit (I) and having a base (a) different from the -COOR ³ group and represented by -C(R ¹ )(OR ^A )(CF ₃ ). With the radiation sensitive resin composition, the receding contact angle of the photoresist film can be made larger at the time of liquid immersion exposure, becomes smaller after development, and can suppress the occurrence of development defects.

Although the reason why the radiation-sensitive resin composition for liquid immersion exposure has the structural unit (I) and exhibits the above-described effects is not clear, it is presumed as follows. That is, the [A] polymer has a group represented by -C(R ¹ )(OR ^A )(CF ₃ ) (a) having a fluorine atom to contribute to the high hydrophobicity of the [A] polymer. On the other hand, this group imparts high hydrophobicity to the [A] polymer by ionization or the like by the action of an alkali developing solution. Further, in the structural unit (I), the group (a) is present at the above specific position different from the -COOR ³ group. Due to the specific molecular structure, it is considered that the hydrophobicity and hydrophilicity can be effectively exhibited. As a result, the surface of the photoresist film formed by the immersion-sensitive radiation-sensitive resin composition can be made to have a receding contact angle in the liquid. The immersion exposure is higher than in the past and can be greatly reduced after development. Further, after the development, by making the receding contact angle small, the developing solution and the washing liquid can be brought into better contact with the surface of the resist film, and the occurrence of development defects can be suppressed.

In the above formula (1), R ¹ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, R ² is a single bond, a divalent chain hydrocarbon group having 1 to 20 carbon atoms, and a divalent carbon number of 3 to 20 An alicyclic hydrocarbon group, or a combination of one or more of these and -O-, R ³ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, and R ^A is a hydrogen atom or a carbon number of 1~ 20 one-price organic base.

The one-valent organic group having 1 to 20 carbon atoms represented by R ¹ and R ³ is exemplified as a monovalent chain hydrocarbon group, a monovalent alicyclic hydrocarbon group, a monovalent aromatic hydrocarbon group or one or more of these. a group in which a linking group containing a hetero atom such as -O-, -CO-, -OCO-, -COO-, or -S- is combined. Some or all of one of the hydrogen atoms of the groups may be substituted with a fluorine atom, a hydroxyl group, a carboxyl group, an amine group, a cyano group or the like.

The monovalent chain hydrocarbon group is exemplified by an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group; an alkenyl group such as a vinyl group, a propenyl group or a butenyl group; and an alkyne such as an ethynyl group, a propynyl group or a butynyl group; Base.

The above monovalent alicyclic hydrocarbon group is exemplified by a cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group; a cyclopropenyl group, a cyclobutenyl group, a cyclopentene group; a cycloalkenyl group such as a cyclohexenyl group or a norbornene group.

The monovalent aromatic hydrocarbon group is exemplified by an aryl group such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group or a fluorenyl group; an aralkyl group such as a benzyl group, a phenethyl group, a naphthylmethyl group or a fluorenylmethyl group.

As for R ¹ , from the viewpoint of increasing the receding contact angle at the time of immersion exposure of the formed photoresist film, a hydrogen atom, a monovalent chain hydrocarbon group, a monovalent alicyclic hydrocarbon group, and monovalent fluorination are preferred. The chain hydrocarbon group and the monovalent fluorinated alicyclic hydrocarbon group are more preferably a hydrogen atom or a monovalent perfluoroalkyl group, more preferably a hydrogen atom or a trifluoromethyl group, and most preferably a trifluoromethyl group.

As for R ³ , from the viewpoint of increasing the receding contact angle at the time of immersion exposure of the formed photoresist film, a hydrogen atom, a monovalent chain hydrocarbon group, a monovalent alicyclic hydrocarbon group, and monovalent fluorination are preferred. The chain hydrocarbon group, monovalent fluorinated alicyclic hydrocarbon group, more preferably methyl group, ethyl group, cyclohexyl group, hexafluoro-2-propyl group, more preferably hexafluoro-2-propyl group.

The divalent chain hydrocarbon group having 1 to 20 carbon atoms represented by R ² is exemplified by, for example, methanediyl, ethanediyl, propanediyl, butanediyl, pentanediyl, hexanediyl, octane II. Base, decanediyl, dodecanediyl, tetradecanediyl, hexadecanediyl, octadecyldiyl, eicosyldiyl and the like.

The divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ² is exemplified by a cyclopropyldiyl group, a cyclobutanediyl group, a cyclopentadienyl group, a cyclohexanediyl group, a cyclooctyldiyl group, a cyclodecanediyl group and the like.

A group in which one or more of the above-mentioned chain hydrocarbon group and alicyclic hydrocarbon group represented by R ² is combined with -O-, and is exemplified by, for example, methanediyloxy group, ethanediyloxy group, and propane II. Alkyldiyloxy such as methoxy, butanediyloxy, pentanediyloxy, hexanediyloxy, octanediyloxy; methanediyloxymethanediyl, methanediyl Oxyethanediyl, methanediyloxy (1,2-propanediyl), methanediyloxybutanediyl, methanediyloxycyclohexanediyl, etc. containing one -O- A group containing two or more -O- groups such as a propane di-oxycarbonylethane diyloxyethane diyl group.

In these R ² in view of enhancing the receding contact angle on the time of immersion of the surface of the exposed resist film is formed, it is preferably a combination of a divalent chain hydrocarbon group, a divalent chain hydrocarbon group having two to one -O-based group, preferably a combination of a divalent chain hydrocarbon group having 1 to 4 carbon atoms or a divalent chain hydrocarbon group having 1 to 4 carbon atoms and a -O- group, and Preferably, it is a combination of a divalent chain hydrocarbon group having 2 or 3 carbon atoms or two divalent chain hydrocarbon groups having 1 to 3 carbon atoms and a -O- group, preferably an ethane diyl group or a methane diyl group. Oxyethanediyl, methanediyloxy (1,2-propanediyl), preferably methanediyloxyethanediyl, methanediyloxy (1,2-propanediyl) .

When R ^A is a hydrogen atom, -C(R ¹ )(OH)(CF ₃ ) in the above formula (1) is exemplified by, for example, 2-hydroxy-1,1,1,3,3,3-hexafluoro- 2-propyl, 1-hydroxy-2,2,2-trifluoroethyl, 2-hydroxy-1,1,1,4,4,4-hexafluoro-2-butyl, 2-hydroxy-1, 1,1,3,3,4,4,4-hexafluoro-2-butyl and the like. In the above, 2-hydroxy-1,1,1,3,3,3-hexafluoro-2-propyl, 1-hydroxy-2,2,2-trifluoroethyl is preferred, more preferably 2 -Hydroxy-1,1,1,3,3,3-hexafluoro-2-propyl.

The one-valent organic group having 1 to 20 carbon atoms represented by R ^A is exemplified by the same group as the one-valent organic group exemplified as the above R ¹ and R ³ . Further, the monovalent organic group is also exemplified by a monovalent alkali dissociable group or the like. The "base dissociable group" means, for example, a group which substitutes a hydrogen atom of a hydroxyl group, and is a group which is dissociated in the presence of a base (for example, in a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) at 23 ° C).

The monovalent base dissociating group is, for example, a group represented by the following formula (Ba-1), a group represented by the following formula (Ba-2), and the like.

In the above formula (Ba-1) and formula (Ba-2), each of R ^{Ba is} independently a hydrocarbon group having 1 to 20 carbon atoms. Part or all of one of the hydrogen atoms of the hydrocarbon group may also be substituted.

The one-valent hydrocarbon group having 1 to 20 carbon atoms represented by the above R ^Ba is exemplified by, for example, one-carbon chain hydrocarbon group having 1 to 20 carbon atoms, one-valent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and one carbon number 6 to 20 Avalent aromatic hydrocarbon group and the like.

The one-carbon chain hydrocarbon group having 1 to 20 carbon atoms, the one-valent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and the one-valent aromatic hydrocarbon group having 6 to 20 carbon atoms are exemplified by, for example, the above R ¹ and R ³ . Various bases are the same.

The substituent represented by the above R ^Ba represents a monovalent hydrocarbon group, for example, a fluorine atom, a hydroxyl group, an amine group, a thiol group, a carboxyl group, a cyano group, an alkoxy group, a decyl group, a decyloxy group or the like.

The above R ^{Ba is} preferably a monovalent chain hydrocarbon group, more preferably a one-valent chain hydrocarbon group having 1 to 5 carbon atoms, more preferably a methyl group.

The group represented by the above formula (Ba-1) and the group represented by the formula (Ba-2) are exemplified by a group represented by the following formula, and the like.

R ^{A is} preferably a hydrogen atom or a monovalent base dissociable group, more preferably a hydrogen atom. By making R ^A the above-mentioned group, it is considered that ionization or the like due to the action of the alkali developing solution can be more effectively caused, and the surface recoil contact angle of the photoresist film after development can be made smaller. As a result, the occurrence of development defects in the photoresist pattern formed by the radiation-sensitive resin composition for liquid immersion exposure can be further suppressed.

The unit structure (I) is exemplified by a structural unit represented by the following formulas (I-1) to (I-18).

Among these, it is preferably a structural unit represented by the above formulas (1-1) to (1-9), (1-13), and (1-16), and more preferably the above formula (1-1). The structural unit represented by (1-2), (1-4), (1-5), (1-6), and (1-16) is more preferably the above formula (1-4), (1-5) ) and (1-6) indicate the structural unit.

Further, the structural unit (I) is also exemplified by, for example, the hydrogen atom of the -(CF ₃ ) ₂ C-OH group in the structural unit represented by the above formula (1-1) to (1-18) via the above (Ba-1) Or the formula (Ba-2) represents a structural unit in which one-valent base dissociable group is substituted.

The content ratio of the structural unit (I) is preferably from 1 mol% to 100 mol%, more preferably from 10 mol% to 98 mol%, based on the entire structural unit constituting the [A] polymer. More preferably, it is 30 mol% or more and 95 mol% or less, preferably 60 mol% or more and 90 mol% or less. By setting the content ratio of the structural unit (I) in the [A] polymer to the above range, the receding contact angle of the formed photoresist film can be made larger at the time of liquid immersion exposure, and can be made smaller after development. And the occurrence of development defects can be further suppressed.

The polymer [A] can be obtained by subjecting a monomer having a structural unit (I) to a radical polymerization of a monomer having another structural unit as needed, as will be described later. A method for synthesizing a compound of the structural unit (I) is as follows, when R ² is the following compound (i) of -R ^2a -O-(CH ₂ ) _n -. As the compound which obtains the structural unit (I) in which R ² is fluorine and -R ^2a -O-(CH ₂ ) _n -, a conventional compound can be used. For example, the compound described in JP-A-2002-210420, JP-A-2002-155112, and JP-A-2005-107476, etc., may be mentioned.

In the above formulae (ia), (ib) and (i), R ¹ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ^2a is a divalent chain hydrocarbon group having 1 to 16 carbon atoms or a group in which the chain hydrocarbon group and the -O- group are combined. R ³ is a hydrogen atom or a one-valent organic group having 1 to 20 carbon atoms. R ^A is a hydrogen atom or a one-valent organic group having 1 to 20 carbon atoms. X is a halogen atom. n is an integer from 1 to 4.

By reacting the hydroxy compound represented by the above formula (ia) with a haloalkyl acrylate compound represented by the above formula (ib) in a solvent such as dichloromethane in the presence of an alkali compound such as triethylamine, The compound (i) represented by the above formula. When R ^A is a hydrogen atom, among the compounds represented by the formula (ia), among the two hydroxyl groups, the reactivity of the hydroxyl group bonded to the carbon atom adjacent to the CF ₃ group is low, so that a compound having a good yield can be obtained ( i).

The halogen atom represented by the above X is exemplified by a fluorine atom, a halogen atom, a bromine atom, an iodine atom or the like. Among these, a bromine atom is preferred from the viewpoint of reaction yield.

[structural unit (II)]

The structural unit (II) is a structural unit containing an acid-dissociable group. The "acid dissociable group" means a group which substitutes a hydrogen atom such as a carboxyl group or a hydroxyl group, and is a group which is dissociated by the action of an acid. By making the [A] polymer have a structural unit (II), The dissolution residue of the exposure liquid to the developing liquid can be further suppressed. As a result, according to the radiation sensitive linear resin composition for liquid immersion exposure, generation of development defects can be further suppressed.

The structural unit (II) is exemplified by a structural unit represented by the following formula (2), and the like.

In the above formula (2), R ⁴ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ⁵ is an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 4 to 20 carbon atoms. R ⁶ and R ^{7 are} each independently an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 4 to 20 carbon atoms, or R ⁶ and R ⁷ are bonded to each other, and together with the carbon atoms bonded thereto form two A cyclic base.

From the viewpoint of obtaining the copolymerizability of the monomer of the structural unit (II), R ⁴ is preferably a hydrogen atom or a methyl group, more preferably a methyl group.

The alkyl group having 1 to 6 carbon atoms represented by R ⁵ to R ⁷ is exemplified by a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, a second butyl group, a t-butyl group or the like. Among these, a methyl group, an ethyl group, and an isopropyl group are preferred.

The above alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ⁵ to R ⁷ is exemplified by a monocyclic cycloalkyl group such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group or a cyclooctyl group; a norbornyl group and an adamantane group; A polycyclic cycloalkyl group or the like. Among these, a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group are preferred.

The divalent cyclic group in which R ⁶ and R ⁷ are bonded to each other is exemplified by a monocyclic cycloalkanediyl group such as a cyclopentadienyl group, a cyclohexanediyl group or a cyclooctyldiyl group; a norbornanediyl group, adamantane a monocyclic divalent alicyclic heterocyclic group such as a dibasic or polycyclic cycloalkanediyl group; azacyclopentadienyl group, oxetanyl group or the like; aza-norbornanediyl group, oxanorbornane A polycyclic divalent aliphatic heterocyclic group such as a dibasic group or the like. In the above, a monocyclic cycloalkanediyl group or a polycyclic cycloalkanediyl group is preferred, and more preferably a cyclopentadienyl group, a cyclohexanediyl group, a cyclooctadienyl group, a norbornanediyl group, an adamantanediyl group, More preferably, it is a cyclopentanediyl group or an adamantanediyl group.

The structural unit (II) is preferably a structural unit having an alkanediyl group in which R ⁶ and R ⁷ are bonded to each other, and more preferably a structural unit derived from 1-alkyl-1-cycloalkyl (meth)acrylate. The structural unit derived from 2-alkyl-2-adamantyl (meth)acrylate, more preferably a structural unit derived from 1-alkyl-1-cycloalkyl (meth)acrylate, preferably The structural unit derived from 1-alkyl-1-cyclopentyl (meth)acrylate is preferably a structural unit derived from 1-methyl-1-cyclopentyl (meth)acrylate.

The monomer which obtains the structural unit (II) is exemplified by a monomer represented by the following formula (2-1) to (2-11) (hereinafter also referred to as "monomer (2-1) to (2-11)). ")Wait.

Among the above monomers, monomers (2-2), (2-3), (2-4), (2-9) and (2-10) are preferred, and more preferably monomers (2-2). .

The content ratio of the structural unit (II) is preferably from 5 mol% to 90 mol%, more preferably from 8 mol% to 60 mol%, based on the total structural unit of the [A] polymer. More preferably, it is 10 mol% or more and 40 mol% or less. By making the content ratio of the structural unit (II) in the above range, the radiation-sensitive resin composition for liquid immersion exposure can further suppress the dissolution residue of the [A] polymer to the developing liquid in the exposed portion, and as a result, it can be further Inhibit the occurrence of imaging defects.

[structural unit (III)]

The structural unit (III) is a structural unit containing a fluorine atom (except for the structural unit (I)). [A] The polymer has a fluorine atom in the structural unit (I), so the structural unit (III) is not necessarily required, but the [A] polymer further has a structural unit (III), thereby increasing the fluorine atom content. Can promote the bias towards the surface of the photoresist.

The structural unit (III) is, for example, a structural unit represented by the above formula (3-1) (hereinafter also referred to as "structural unit (III-1)"), and a structural unit represented by the formula (3-2) ( Hereinafter, it is also referred to as "structural unit (III-2)"), a structural unit represented by the formula (3-3) (hereinafter also referred to as "structural unit (III-3)").

In the above formula (3-1), R ⁸ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R ⁹ is a linear or branched alkyl group having a fluorine atom of 1 to 6 carbon atoms or has The carbon atom of the fluorine atom is 4 to 20 one-valent alicyclic hydrocarbon group. However, some or all of the hydrogen atoms of the above alkyl group and the alicyclic hydrocarbon group may be substituted.

In the above formula (3-2), R ¹⁰ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹¹ is a linking group of (k+1) valence. k is an integer from 1 to 3. X is a divalent linking group having a fluorine atom. R ¹² is a hydrogen atom or a monovalent organic group. However, when k is 2 or 3, the plurality of X and R ¹² may be the same or different.

In the above formula (3-3), R ¹³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹⁴ is a (m+1)-valent linking group having no fluorine atom. m is an integer from 1 to 3. A ¹ is -COO-. R ¹⁵ is a monovalent hydrocarbon group containing at least one fluorine atom. However, when m is 2 or 3, the plurality of A ¹ and R ¹⁵ may be the same or different.

The linear or branched alkyl group having 1 to 6 carbon atoms and having a fluorine atom represented by R ⁹ is a linear or branched carbon number of 1 to 6 such as a methyl group, an ethyl group, a propyl group or a butyl group. A group in which one or all of the hydrogen atoms of the alkyl group has a fluorine atom-substituted group.

The above-mentioned carbon number 4 to 20 one-valent alicyclic hydrocarbon group having a fluorine atom represented by R ⁹ is exemplified by, for example, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, norbornyl, adamantyl, cyclopentane. A group having a carbon number of 4 to 20, such as a methyl group or a cyclohexylmethyl group, having a part or all of a hydrogen atom of a one-valent alicyclic hydrocarbon group having a carbon atom and the like.

The above-mentioned (k+1)-valent linking group represented by R ¹¹ is, for example, a linear or branched hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, and a carbon number of 6 to 30. An aromatic hydrocarbon group or a group in which one or more groups selected from the group consisting of -O-, -S-, -NH-, -CO-, and -CS- are combined. Further, the above (k+1)-valent linking group may have a substituent.

The above linear or branched hydrocarbon group having 1 to 30 carbon atoms is exemplified by, for example, methane, ethane, propane, butane, pentane, hexane, heptane, A hydrocarbon group such as decane, eicosane or triacontane is used to remove a group of (k+1) hydrogen atoms.

The alicyclic hydrocarbon group having 3 to 30 carbon atoms is exemplified by, for example, a group obtained by removing (k+1) hydrogen atoms from the following: cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, a monocyclic saturated hydrocarbon such as cyclooctane, cyclodecane, methylcyclohexane or ethylcyclohexane; cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclodecene, Monocyclic unsaturated hydrocarbons such as cyclopentadiene, cyclohexadiene, cyclooctadiene, cyclodecadiene; bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane, tricyclo[5.2. 1.0 ^2,6 ]decane, tricyclo[3.3.1.1 ^3,7 ]decane, tetracyclo[6.2.1.1 ^3,6 .0 ^2,7 ]polycyclic saturated hydrocarbons such as dodecane, adamantane; double ring [2.2.1] heptene, bicyclo[2.2.2]octene, tricyclo[5.2.1.0 ^2,6 ]nonene, tricyclo[3.3.1.1 ^3,7 ]nonene, tetracyclo[6.2.1.1 ^{3 , 6} .0 ^2,7 ] Polycyclic saturated hydrocarbons such as dodecene.

The above aromatic hydrocarbon group having 6 to 30 carbon atoms is exemplified by, for example, benzene, naphthalene, phenanthrene, anthracene, tetracene, pentacene, fluorene, picene, toluene, xylene, ethylbenzene, and mesitylene. An aromatic hydrocarbon such as cumene or the like obtained by removing (k+1) hydrogen atoms.

The divalent linking group having a fluorine atom represented by the above X is, for example, a divalent linear hydrocarbon group having a fluorine atom of 1 to 20 carbon atoms, a divalent group obtained by combining the group and a carbonyl group, and the like. The above X is, for example, a group represented by the following formulas (X-1) to (X-7).

As for X, among these, a group represented by the above formula (X-7) is preferred.

The one-valent organic group represented by R ¹² is, for example, a linear or branched hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, or A group obtained by combining one or more groups selected from the group consisting of an oxygen atom, a sulfur atom, an ether group, an ester group, a carbonyl group, an imine group, and a guanamine group.

The linking group having no (m+1) valence of a fluorine atom represented by R ¹⁴ is, for example, a linear or branched hydrocarbon group having a carbon number of 1 to 30, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, An aromatic hydrocarbon group having 6 to 30 carbon atoms or a hydrocarbon group having 1 to 30 carbon atoms and -CO-, -COO-, -OCO-, -O-, -NR-, -CS-, -S-, -SO- And a base of one or more selected from the group consisting of -SO ₂ -. Represented by R of ¹³ (m + 1) valence of having no linking group fluorine atoms exemplified above as representing the (k + 1) in the above R ¹¹ price of the linking group exemplified the groups as not having the same fluorine atom by Base and so on.

The above-mentioned valent hydrocarbon group containing at least one fluorine atom represented by R ¹⁵ is exemplified by, for example, a fluorinated alkyl group, a fluorinated alicyclic hydrocarbon group, a fluorinated aromatic hydrocarbon group or the like.

The monomer which obtains the structural unit (III-1) is exemplified by, for example, trifluoromethyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, perfluoroethyl (meth)acrylate, Perfluoro- n-propyl (meth)acrylate, perfluoroisopropyl (meth)acrylate, perfluoro-n-butyl (meth)acrylate, perfluoroisobutyl (meth)acrylate, (meth)acrylic acid Fluorinated tert-butyl ester, perfluorocyclohexyl (meth)acrylate, 2-(1,1,1,3,3,3-hexafluoro)propyl (meth)acrylate, 1-(meth)acrylate (2,2,3,3,4,4,5,5-octafluoro)pentyl ester, 1-(2,2,3,3,4,4,5,5-octafluoro)(meth)acrylate Hexyl ester, perfluorocyclohexyl methyl (meth)acrylate, 1-(2,2,3,3,3-pentafluoro)propyl (meth)acrylate, 1-(2,2) ,3,3,4,4,4-heptafluoro)pentyl ester, (meth)acrylic acid 1-(3,3,4,4,5,5,6,6,7,7,8,8,9 , 9,10,10,10-heptadecafluoro)decyl ester, 1-(5-trifluoromethyl-3,3,4,4,5,6,6,6-octafluoro)(meth)acrylate Hexyl ester and the like.

The monomer which obtains the structural unit (III-2) is exemplified by, for example, 2-(1-ethoxycarbonyl-1,1-difluoro)butyl (meth)acrylate and 2-(1- Tributoxycarbonyl-1,1-difluoro)butyl, (meth)acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl) ester, (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl)methacrylate, (meth)acrylic acid (1,1,1-trifluoro-2-tris) Fluoromethyl-2-hydroxy-4-cyclohexyl-4-butyl), (meth)acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-5-pentyl) ) ester, (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) (meth)acrylate, 2-{[5-(1') , 1 ',1'-trifluoro-2'-trifluoromethyl-2'-hydroxy)propyl]bicyclo[2.2.1]heptyl} ester and the like. Among these, 2-(1-tert-butoxycarbonyl-1,1-difluoro)butyl (meth)acrylate and 2-(1-ethoxycarbonyl) (meth)acrylate The benzyl-1,1-difluoro)butyl ester is preferred.

The monomer which obtains the structural unit (III-3) is exemplified by, for example, 2-(1,1,1,3,3,3-hexafluoro-2-propoxycarbonyl)norbornane lactoester (meth)acrylate. , 2-(2,2,2-trifluoroethoxycarbonyl)norbornane lactyl (meth)acrylate, 4-(1,1,1,3,3,3-hexa(meth)acrylate Fluor-2-propoxycarbonyl)cyclohexyl ester, 4-(2,2,2-trifluoroethoxycarbonyl)cyclohexyl (meth)acrylate, and the like.

The structural unit (III) is exemplified by, for example, the following formulas (3-1-1) to (3-1-6), formula (3-2-1) to (3-2-3), and formula (3-3). -1) indicates the structural unit, etc.

In the above formulae (3-1-1) to (3-1-6), the R ⁸ system is synonymous with the above formula (3-1). In the above formulas (3-2-1) to (3-2-3), the R ¹⁰ system is synonymous with the above formula (3-2). In the above formula (3-3-1), the R ¹³ system is synonymous with the above formula (3-3).

Among these, the structural unit represented by the above formula (3-1-1) and the structural unit represented by the formula (3-1-3) are preferable.

The content ratio of the structural unit (III) is preferably from 0 mol% to 90 mol%, more preferably from 0 mol% to 50 mol%, based on the total structural unit of the [A] polymer.

[A] polymers may also have more than one structural unit Other structural units other than (I)~(III). The content ratio of other structural units is preferably 30% by mole or less, more preferably 20% by mole or less.

The content of the polymer (A) is preferably from 0.1% by mass to 50% by mass, more preferably from 0.1% by mass to 20% by mass, based on the total solid content of the radiation-sensitive resin composition for immersion exposure. More preferably, it is 0.5 mass% or more and 15 mass% or less, and is preferably 1 mass% or more and 10 mass% or less.

The content of the polymer [A] is preferably 0.1 parts by mass or more and 20 parts by mass or less, more preferably 0.5 parts by mass or more and 15 parts by mass or less, more preferably 1 part by mass based on 100 parts by mass of the [C] polymer described later. More than 10 parts by mass or less.

<[A] Synthesis Method of Polymer>

The [A] polymer can be synthesized, for example, by polymerizing a monomer which obtains a specific structural unit in a suitable solvent by using a radical polymerization initiator.

The method of the polymerization reaction is exemplified by, for example, a method of dropwise adding a solution containing a monomer and a radical initiator to a solution containing a reaction solvent or a monomer; and a solution containing a monomer and a radical-containing initiator a solution in which a solution is separately added to a solution containing a reaction solvent or a monomer to carry out a polymerization reaction; a plurality of solutions containing each monomer and a solution containing a radical initiator are respectively added dropwise to the reaction solvent or monomer alone A method in which a polymerization reaction is carried out in a solvent.

The above radical initiators are, for example, 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisbutyric acid Ester and the like. These radical initiators may be mixed in two or more types.

The solvent used in the above polymerization is exemplified by, for example, an alkane such as n-pentane, n-hexane, n-heptane, n-octane, n-decane or n-decane; cyclohexane, cycloheptane, cyclooctane, and decahydrogen; Naphthenes such as naphthalene and norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene and cumene; chlorobutanes, bromohexanes, dichloroethanes, hexamethylene Halogenated hydrocarbons such as dibromo and chlorobenzene; saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, methyl propionate; acetone, 2-butanone, 4-methyl-2-pentyl Ketones such as ketone and 2-heptanone; ethers such as tetrahydrofuran, dimethoxyethane and diethoxyethane; methanol, ethanol, 1-propanol, 2-propanol, 4-methyl- An alcohol such as 2-pentanol or the like. Further, these solvents may be used in combination of two or more kinds.

In the polymerization of the synthesized [A] polymer, a molecular weight modifier can be used to adjust the molecular weight. The molecular weight modifiers are exemplified by halogenated hydrocarbons such as chloroform and carbon tetrabromide; n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, tri-dodecyl mercaptan, thioglycolic acid, etc. Thiols; xanthogenates such as dimethyl xanthate disulfide and diisopropyl xanthogen disulfide; terpineolene, α-methylstyrene dimer, and the like.

The reaction temperature in the above polymerization is usually from 40 ° C to 150 ° C, preferably from 50 ° C to 120 ° C. The reaction time is usually from 1 hour to 48 hours, preferably from 1 hour to 24 hours.

The polymer obtained by the polymerization can be recovered by a reprecipitation method. As the reprecipitation solvent, an alcohol solvent or the like can be used.

[A] Polymer The polystyrene-equivalent weight average molecular weight (Mw) measured by a gel permeation chromatography (GPC) is preferably 1,000 or more and 50,000 or less, more preferably 2,000 or more and 30,000 or less, and still more preferably 3,000 or more. 15,000 or less, preferably 3,000 or more and 10,000 or less. By setting the Mw of the [A] polymer to the above range, the polarization of the [A] polymer toward the surface layer of the photoresist film can be promoted, and as a result, the radiation-sensitive film composition for the immersion exposure can form the photoresist film. The retreat contact angle is larger during immersion exposure and becomes smaller after development.

The ratio (Mw/Mn) of the Mw of the polymer to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC is preferably 1 or more and 5 or less, more preferably 1 or more and 3 or less, and still more preferably 1 The above 2 or less is preferably 1.2 or more and 1.6 or less.

Moreover, the Mw and Mn of the polymer in this specification are measured by GPC under the following conditions.

Pipe string: 2 G2000HXL, 1 G3000HXL and 1 G4000HXL (manufactured by TOSOH)

Mobile phase: tetrahydrofuran

Column temperature: 40 ° C

Flow rate: 1.0 ml / min

Sample concentration: 1.0% by mass

Sample injection amount: 100 μL

Detector: differential refractometer

Reference material: monodisperse polystyrene

<[B]acid generator>

[B] The acid generating system generates an acid by exposure, and the acid dissociable group of the [A] polymer and the [C] polymer described later is dissociated by the acid to produce a carboxylic acid. As a result, the polarity of the polymers is increased to make the polymer of the exposed portion soluble in the alkali developing solution. The form of the [B] acid generator in the radiation sensitive linear resin composition for liquid immersion exposure may be a compound form as described later (hereinafter also referred to as "[B] acid generator"), or may be a polymer. The form in which one part is included may also be the form of the two.

The [B] acid generator may, for example, be an onium salt compound, an N-sulfodeoxyquinone imine compound, a halogen-containing compound, a diazoketone compound or the like.

The onium salt compound is exemplified by, for example, an onium salt, a tetrahydrothiophene salt, a phosphonium salt, a phosphonium salt, a diazonium salt, a pyridinium salt or the like.

The onium salt is exemplified by, for example, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfonium perfluorooctanesulfonate, triphenylsulfonium 2-bicyclo[ 2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 2-(1-adamantyl)-1,1-difluoroethanesulfonic acid Salt, 4-cyclohexylphenyldiphenylphosphonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylphosphonium nonafluorobutane sulfonate, 4-cyclohexylphenyldiphenylfluorene perfluoro Octanesulfonate Acid salt, 4-cyclohexylphenyl diphenyl hydrazine 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethane sulfonate, 4-methanesulfonylbenzene Diphenylphosphonium trifluoromethanesulfonate, 4-methanesulfonylphenyldiphenylphosphonium nonafluorobutane sulfonate, 4-methanesulfonylphenyldiphenylphosphonium perfluoro-n-octane Sulfonate, 4-methanesulfonylphenyldiphenylfluorene2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 1,1,2,2-tetrafluoro-6-(1-adamantanecarbonyloxy)-hexane-1-sulfonate.

The tetrahydrothiophene sulfonium salt is exemplified by, for example, 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(4-n-butoxynaphthalen-1-yl)tetra Hydrogenthiophene nonafluoro-n-butane sulfonate, 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene fluorene perfluorooctane sulfonate, 1-(4-n-butoxynaphthalene) -1-yl)tetrahydrothiophene 2-cyclobi[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1-(6-n-butoxynaphthalene- 2-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene nonafluoro-n-butane sulfonate, 1-(6-n-butyl Oxynaphthalen-2-yl)tetrahydrothiophene fluorene perfluoro-n-octane sulfonate, 1-(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene quinone 2-bicyclo[2.2.1]heptane- 2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene trifluoromethanesulfonate, 1- (3,5-Dimethyl-4-hydroxyphenyl)tetrahydrothiophene nonafluoro-n-butane sulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene Fluorane n-octane sulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene 2-cyclo[2.2.1]hept-2-yl-1,1,2,2 - tetrafluoroethane sulfonate and the like.

The onium salt is exemplified by, for example, diphenylsulfonium trifluoromethanesulfonate, diphenylsulfonium nonafluorobutanesulfonate, diphenylphosphonium perfluorooctanesulfonate, diphenylphosphonium 2-bicyclopropane. [2.2.1]Hept-2-yl-1,1,2,2-tetrafluoroethane sulfonate Acid salt, bis(4-tert-butylphenyl)phosphonium trifluoromethanesulfonate, bis(4-tert-butylphenyl)phosphonium nonafluorobutane sulfonate, double (4-third Phenyl phenyl) fluorinated perfluorooctane sulfonate, bis(4-t-butylphenyl) fluorene 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoro Ethane sulfonate and the like.

The N-sulfonyloxyimide compound is exemplified by, for example, N-(trifluoromethanesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylimideimine, N-(nine Fluorine butane sulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylimenine, N-(perfluoro-n-octanesulfonyloxy)bicyclo[2.2.1] Hg-5-ene-2,3-dicarboxylimenine, N-(2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) Bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylimenimine and the like.

Preferably, the onium salt compound is more preferably a phosphonium salt, more preferably a triphenylsulfonium perfluoroalkanesulfonate, more preferably triphenylsulfonium nonafluorobutanesulfonate.

[B] The content of the acid generator is such that the content of the [B] acid generator is an acid generator, and the sensitivity and development of the radiation-sensitive resin composition for immersion exposure are ensured. A] 100 parts by mass of the polymer, usually 0.5 parts by mass or more and 20,000 parts by mass or less, preferably 5 parts by mass or more and 10,000 parts by mass or less, more preferably 10 parts by mass or more and 1,000 parts by mass or less, and most preferably 50 parts by mass or more. 500 parts by mass or less.

In addition, the content of the [B] acid generator is preferably from 100 parts by mass of the [C] polymer to be described later, from the viewpoint of the sensitivity and developability of the radiation-sensitive resin composition for liquid immersion exposure. 0.1 parts by mass or more and 20 parts by mass or less, more preferably 0.5 parts by mass or more and 17 parts by mass or less, More preferably, it is 1 part by mass or more and 15 parts by mass or less.

By setting the content of the [B] acid generator to the above range, the sensitivity and developability of the radiation sensitive resin composition for liquid immersion exposure can be improved. The [B] acid generators may be used alone or in combination of two or more.

<[C]polymer>

The [C] polymer is a polymer having a fluorine atom content lower than that of the [A] polymer, and is a polymer having an acid dissociable group. The [C] polymer is a polymer which becomes a base polymer in the radiation sensitive resin composition for liquid immersion exposure. Further, the term "base polymer" means a polymer which is a main component of a polymer constituting a photoresist film formed of a radiation-sensitive resin composition, and preferably means 50 mass with respect to all the polymers constituting the photoresist film. More than % of the polymer.

[C] The fluorine atom content of the polymer is smaller than the fluorine atom content of the [A] polymer, so that the [A] polymer can be effectively biased to the surface of the formed photoresist film, and as a result, the liquid immersion The radiation-sensitive resin composition for exposure can make the formed contact film have a large receding contact angle at the time of liquid immersion exposure, and become small after development.

The content of the fluorine atom of the [C] polymer is preferably less than 5% by mass, more preferably 3% by mass or less, still more preferably 1% by mass or less.

[C] The polymer has a structural unit containing an acid-dissociable group (hereinafter also referred to as "structural unit (C-II)"), and preferably has, for example, a lactone structure and a cyclic carbonic acid, in addition to the structural unit. a structural unit of at least one structure selected from the group consisting of an ester structure and a sultone structure (hereinafter also referred to as "Structural unit (IV)"), and may have other structural units than those structural units. The [C] polymer may have one or two or more structural units. Hereinafter, each structural unit will be described.

[structural unit (C-II)]

By causing the [C] polymer to have a structural unit (C-II), the acid dissociable group is dissociated by the action of an acid generated from the [B] acid generator to generate a carboxyl group or the like. As a result, the polarity of the [C] polymer changes, and the solubility to the alkali developing solution is changed.

The structural unit (C-II) is not particularly limited as long as it has an acid-dissociable group, and is exemplified by, for example, a structural unit (II) in the above [A] polymer.

The structural unit (C-II) is preferably a structural unit derived from 1-alkyl-1-cycloalkyl (meth)acrylate derived from 2-alkyl-2-adamantyl (meth)acrylate. The structural unit is more preferably a structural unit derived from 1-alkyl-1-cyclopentyl (meth)acrylate, a structural unit derived from 2-alkyl-2-adamantyl (meth)acrylate, and more It is preferably a structural unit derived from 1-methyl-1-cyclopentyl (meth)acrylate, a structural unit derived from 1-ethyl-1-cyclopentyl (meth)acrylate, derived from (methyl) a structural unit of 1-isopropyl-1-cyclopentyl acrylate, a structural unit derived from 2-methyl-2-adamantyl (meth)acrylate, derived from 2-ethyl-2(meth)acrylate - The structural unit of adamantyl ester.

The monomer which obtains the structural unit (C-II) is exemplified as the monomer which obtains the structural unit (II) of the above [A] polymer, and the monomer (2-2), (2-3), 2-4), (2-9) and (2-10) are preferred.

The proportion of the structural unit (C-II) relative to the composition [C] The total structural unit of the compound is preferably 10 mol% or more and 90 mol% or less, more preferably 30 mol% or more and 80 mol% or less, and more preferably 40 mol% or more and 70 mol% or less. By setting the content ratio of the structural unit (C-II) to the above range, the pattern formation property of the radiation sensitive resin composition for liquid immersion exposure can be improved.

[structural unit (IV)]

The structural unit (IV) is a structural unit including a structure selected from at least one of a group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure. By having the structural unit (IV) of the [C] polymer, the adhesion of the photoresist film formed by the radiation-sensitive resin composition for liquid immersion exposure to the substrate can be improved.

The monomer which obtained the structural unit (IV) is, for example, a monomer represented by the following formula (4-1) to (4-14).

Among the above monomers, the monomer (4-1), the monomer (4-2), and the monomer (4-3) are preferred, and more preferably the monomer (4-1).

The content ratio of the structural unit (IV) is preferably 10 mol% or more and 80 mol% or less, more preferably 20 mol% or more and 70 mol% or less, and more preferably 20 mol% or less, and more preferably all structural units constituting the [C] polymer. It is preferably 30% or more and 60% or less. By setting the content ratio of the structural unit (IV) to the above range, the adhesion of the photoresist film formed by the radiation-sensitive resin composition for liquid immersion exposure to the substrate can be improved.

[Other construction units]

The [C] polymer may have, for example, a structural unit containing a polar group as a structural unit other than the structural unit (C-II) and the structural unit (IV). The polar group is exemplified by, for example, a carboxyl group, a hydroxyl group, a cyano group, a nitro group, a sulfonamide group or the like. Among these, a carboxyl group and a hydroxyl group are preferred. The content ratio of the other structural unit is preferably 30 mol% or less, more preferably 20 mol% or less, based on the entire structural unit constituting the [C] polymer.

The content of the [C] polymer is preferably 500 parts by mass or more and 10,000 parts by mass or less, more preferably 700 parts by mass or more and 7,000 parts by mass or less, and still more preferably 1,000 parts by mass or more based on 100 parts by weight of the [A] polymer. 4,000 parts by mass or less.

The content of the [C] polymer is preferably 70% by mass or more, more preferably 75% by mass or more, and still more preferably 80% by mass or more based on the total solid content of the radiation-sensitive resin composition for liquid immersion exposure.

<[C] Polymer Synthesis Method>

The [C] polymer can be synthesized by using a monomer which obtains a specific structural unit in the same manner as the synthesis method of the above [A] polymer.

The Mw of the [C] polymer is preferably 1,000 or more and 50,000 or less, more preferably 2,000 or more and 30,000 or less, still more preferably 3,000 or more and 15,000 or less, and most preferably 3,000 or more and 10,000 or less. By setting the Mw of the [C] polymer to the above range, the lithographic performance such as sensitivity and resolution of the radiation sensitive resin composition for liquid immersion exposure can be improved.

The Mw/Mn of the [C] polymer is preferably 1 or more and 5 or less, more preferably 1 or more and 3 or less, still more preferably 1 or more and 2 or less, and most preferably 1.2 or less. Above 1.6 or below. By setting the Mw/Mn of the [C] polymer to the above range, the lithographic performance such as the sensitivity and the resolution of the radiation sensitive resin composition for liquid immersion exposure can be improved.

<[D] Acid Diffusion Control Body>

The radiation sensitive linear resin composition for immersion exposure preferably further contains a [D] acid diffusion control body. The [D] acid diffusion controller controls the diffusion of an acid generated from the [B] acid generator by exposure to light in the photoresist film, and exhibits an effect of suppressing a poor chemical reaction in the unexposed portion. By further including the [D] acid diffusion control material in the radiation-sensitive resin composition for liquid immersion exposure, it is possible to improve the lithographic performance such as resolution while maintaining the characteristics of the receding contact angle and the like. The form of the [D] acid diffusion controlling agent in the radiation sensitive linear resin composition for liquid immersion exposure may be a compound form as described later (hereinafter referred to as "[D] acid diffusion controlling agent"), or may be used as The form in which one part of the polymer is incorporated may also be in the form of the two.

The [D] acid diffusion controlling agent is exemplified by, for example, an amine compound containing an N-third alkoxycarbonyl group, a tertiary amine compound, a quaternary ammonium hydroxide compound, and the like.

The amine compound containing an N-third alkoxycarbonyl group is exemplified by, for example, N-tert-butoxycarbonyldi-n-octylamine, N-third pentyloxycarbonyldi-n-octylamine, N-tert-butoxy group. Carbonyl di-n-decylamine, N-third pentyloxycarbonyldi-n-decylamine, N-tert-butoxycarbonyldi-n-decylamine, N-third pentyloxycarbonyldi-n-decylamine, N -T-butoxycarbonyldicyclohexylamine, N-third pentyloxycarbonyldicyclohexylamine, N-tert-butoxycarbonyl-1-gold R-alkylamine, N-third pentyloxycarbonyl-1-adamantylamine, N-tert-butoxycarbonyl-2-adamantylamine, N-third pentyloxycarbonyl-2-adamantane Amine, N-tert-butoxycarbonyl-N-methyl-1-adamantylamine, N-third pentyloxycarbonyl-N-methyl-1-adamantylamine, (S)-( -)-1-(t-butoxycarbonyl)-2-pyrrolidinemethanol, (S)-(-)-1-(third pentyloxycarbonyl)-2-pyrrolidinemethanol, (R)-( +)-1-(t-butoxycarbonyl)-2-pyrrolidinemethanol, (R)-(+)-1-(third pentyloxycarbonyl)-2-pyrrolidinemethanol, N-third Oxycarbonyl-4-hydroxypiperidine, N-third pentyloxycarbonyl-4-hydroxypiperidine, N-tert-butoxycarbonylpyrrolidine, N-third pentyloxycarbonylpyrrolidine, N,N '-Di-tert-butoxycarbonylpiperazine, N,N'-di-third pentyloxycarbonylpiperazine, N,N-di-t-butoxycarbonyl-1-adamantylamine, N,N- Di-tert-methoxycarbonyl-1-adamantylamine, N-tert-butoxycarbonyl-4,4'-diaminodiphenylmethane, N-third pentyloxycarbonyl-4,4' -diaminodiphenylmethane, N,N'-di-t-butoxycarbonylhexamethylenediamine, N,N'-di-third pentyloxycarbonyl Methylenediamine, N,N,N',N'-tetra-tert-butoxycarbonylhexamethylenediamine, N,N,N',N'-tetradecyloxycarbonylhexamethylene Diamine, N,N'-di-t-butoxycarbonyl-1,7-diaminoheptane, N,N'-di-third pentyloxycarbonyl-1,7-diaminoheptane, N,N'-di-t-butoxycarbonyl-1,8-diaminooctane, N,N'-di-third pentyloxycarbonyl-1,8-diaminooctane, N,N' -Di-tert-butoxycarbonyl-1,9-diaminodecane, N,N'-di-third pentyloxycarbonyl-1,9-diaminodecane, N,N'-di third Butoxycarbonyl-1,10-diaminodecane, N,N'-di-third pentyloxycarbonyl-1,10-diaminodecane, N,N'-di-t-butoxycarbonyl -1,12-diaminododecane, N,N'-di-third pentyloxycarbonyl-1,12-diaminododecane, N,N'-di-t-butoxycarbonyl 4-,4'-diaminodiphenylmethane, N,N'-di-third pentyloxycarbonyl-4,4'-diaminodiphenylmethane, N-tert-butoxycarbonylbenzene Imidazole, N-tert-butoxycarbonylbenzimidazole, N-third pentyloxycarbonyl-2-methylbenzimidazole, N-tert-butoxycarbonyl-2-phenylbenzimidazole, N - Third pentyloxycarbonyl-2-phenylbenzimidazole and the like.

The above tertiary amine compound is exemplified by, for example, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, cyclohexyl Tri(cyclo)alkylamines such as dimethylamine, dicyclohexylmethylamine, tricyclohexylamine; aniline, N-methylaniline, N,N-dimethylaniline, 2-methylaniline, 3 Aromatic amines such as methylaniline, 4-methylaniline, 4-nitroaniline, 2,6-dimethylaniline, 2,6-diisopropylaniline; triethanolamine, N,N-di ( Alkanolamines such as hydroxyethyl)aniline; N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-indole (2-hydroxypropyl)ethylenediamine, 1,3-bis[1-(4-aminophenyl)-1-methylethyl]benzenetetramethylenediamine, bis(2-dimethylaminoethyl)ether, bis(2-di Ethylaminoethyl ether and the like.

The above-mentioned quaternary ammonium hydroxide is exemplified by, for example, tetra-n-propylammonium hydroxide or tetra-n-butylammonium hydroxide.

Among these, an amine-based compound containing an N-third alkoxycarbonyl group is preferred, more preferably a cyclic amine compound containing an N-third alkoxycarbonyl group, and more preferably an N-third alkoxy group. Carbonyl-4-hydroxypiperidine, preferably N-third pentyloxycarbonyl-4-hydroxypiperidine.

The [D] acid diffusion controlling agent may also use an onium salt compound which is alkaline as an acid diffusion controlling property by exposure decomposition. As for the bismuth salts The compound is, for example, an onium salt compound represented by the following formula (5-1), an onium salt compound represented by the following formula (5-2), and the like.

In the above formula (5-1) and formula (5-2), R ¹⁶ to R ²⁰ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyl group or a halogen atom. Z ^- and E ^- are OH ^- , R ²¹ -COO ^- , R ²¹ -SO ₃ ^- or an anion represented by the following formula (6). R ^{21 is} each independently an alkyl group, an aryl group or an aralkyl group.

The onium salt compound and the onium salt compound are exemplified by, for example, triphenylsulfonium hydrogen peroxide, triphenylsulfonium acetate, triphenylsulfonium salicylate, diphenyl-4-hydroxyphenylhydrazine hydroperoxide, and Phenyl-4-hydroxyphenyl hydrazine acetate, diphenyl-4-hydroxyphenylhydrazine salicylate, bis(4-tert-butylphenyl)hydrazine hydroperoxide, bis(4-third butyl Phenyl) guanidine acetate, double (4- Tributylphenyl) hydrazine hydroperoxide, bis(4-t-butylphenyl)phosphonium acetate, bis(4-t-butylphenyl)hydrazine salicylate, 4-tert-butylbenzene 4-hydroxyphenylhydrazine hydroperoxide, 4-t-butylphenyl-4-hydroxyphenylhydrazine acetate, 4-tert-butylphenyl-4-hydroxyphenylhydrazine salicylate, Bis(4-tert-butylphenyl)indole-10-camphorsulfonate, diphenylphosphonium 10-camphorsulfonate, triphenylsulfonium 10-camphorsulfonate, 4-tert-butoxyphenyl . Diphenylhydrazine 10-camphorsulfonate and the like.

When the [D] acid diffusion controlling agent is a [D] acid diffusion controlling agent, it is preferably 20,000 parts by mass or less, more preferably 5 parts by mass based on 100 parts by mass of the [A] polymer. The amount is preferably 10,000 parts by mass or less, more preferably 10 parts by mass or more and 1,000 parts by mass or less, more preferably 50 parts by mass or more and 500 parts by mass or less.

Further, the content of the [D] acid diffusion controlling agent is preferably 0.1 parts by mass or more and 20 parts by mass or less, more preferably 0.5 parts by mass or more and 17 parts by mass or less, more preferably 100 parts by mass or less based on 100 parts by mass of the [C] polymer. 1 part by mass or more and 15 parts by mass or less.

By setting the content of the [D] acid diffusion controlling agent to the above range, the shape of the resist pattern obtained by the radiation-sensitive resin composition for liquid immersion exposure is improved. The [D] acid diffusion controlling agent may be used alone or in combination of two or more.

<[E] Solvent>

The radiation sensitive linear resin composition for immersion exposure usually contains an [E] solvent. [E] The solvent is any solvent as long as it is soluble or dispersible [A] polymer, [B] acid generator, [C] polymer, [D] acid diffusion controller, and optionally The ingredients are not particularly limited. The solvent of [E] is exemplified by, for example, an alcohol, an ether, a ketone, a guanamine or an ester. [E] The solvent may be used alone or in combination of two or more.

The alcohols are listed, for example, as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, second butanol, third butanol, n-pentanol, isoamyl alcohol, 2-methylbutanol , second pentanol, third pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, second hexanol, 2-ethylbutanol, second heptanol, 3-heptanol , n-octanol, 2-ethylhexanol, second octanol, n-nonanol, 2,6-dimethyl-4-heptanol, n-nonanol, second-undecyl alcohol, trimethyl hydrazine Alcohol, second-tetradecanol, second heptadecyl alcohol, decyl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, two Monools such as acetol; ethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5 - Polyhydric alcohols such as hexanediol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol; Methyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2- Ethyl butyl ether, diethylene glycol single Ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, Polyol partial ethers such as propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, and the like.

Ethers are listed as, for example, a dialkyl ether such as diethyl ether, dipropyl ether or dibutyl ether; an ether containing an aromatic ring such as diphenyl ether or anisole; a cyclic ether such as tetrahydrofuran or tetrahydropyran.

The ketones are exemplified by, for example, acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, diethyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, ethyl n-butyl Chain ketones such as ketone, methyl n-hexyl ketone, diisobutyl ketone, and trimethyl fluorenone; cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, etc. Ketones; diketones such as 2,4-pentanedione and etidylacetone; and ketones containing an aromatic ring such as acetophenone.

The guanamines are exemplified by, for example, N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N, Chain amides such as N-dimethylacetamide and N-methylpropionamide; cyclic guanamines such as N,N-dimethylimidazolidone and N-methylpyrrolidone.

The esters are exemplified by, for example, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, second butyl acetate, n-amyl acetate, second amyl acetate, 3-methoxybutyl acetate, methyl amyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, acetic acid An ester such as ester, methyl acetoxyacetate or ethyl acetoxyacetate; Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, acetic acid Acetate of propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, etc. Diacetate diol, methoxytris-acetate, ethyl propionate, n-butyl propionate, isoamyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, lactate B Ester, n-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate, etc.; lactones such as γ-butyrolactone and γ-valerolactone; Carbonic acid esters such as diethyl carbonate and propylene carbonate.

The hydrocarbons are exemplified by, for example, n-pentane, isopentane, n-hexane, isohexane, n-heptane, isoheptane, 2,2,4-trimethylpentane, n-octane, isooctane, cyclohexane. , aliphatic hydrocarbons such as methylcyclohexane; benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, cumene, diethyl An aromatic hydrocarbon such as benzene, isobutylbenzene, triethylbenzene, diisopropylbenzene or n-pentylnaphthalene.

Among these, esters and ketones are preferred, and acetates, cyclic ketones, lactones of polyhydric alcohol partial ethers, and more preferably propylene glycol monomethyl ether, cyclohexanone, or γ. - Butyrolactone.

<Other optional ingredients>

The radiation sensitive linear resin composition for liquid immersion exposure may contain other optional components such as a surfactant and a sensitizer in addition to the above [A] to [E] components. The radiation sensitive linear resin composition for liquid immersion exposure may contain one or two or more kinds of other optional components.

[Surfactant]

The surfactant has an effect of improving the coatability, the streak property, the development property, and the like of the radiation sensitive resin composition for liquid immersion exposure. As the surfactant, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octyl phenyl ether, polyoxyethylene n-decyl phenyl ether, poly A nonionic surfactant such as ethylene glycol dilaurate or polyethylene glycol distearate. Commercially available products are, for example, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), POLYFLOW No. 75, POLYFLOW No. 95 (the above is manufactured by Kyoei Chemical Co., Ltd.), EF TOP EF301, EF TOP EF303, and EF TOP EF352 (the above is manufactured by TOHCHEM PRODUCTS). ), MEGAFAC F171, MEGAFAC F173 (manufactured by DIC), FLORARD FC430, FLORARD FC431 (above Sumitomo 3M), ASAHI GUARD AG710, SURFLON S-382, SURFLON SC-101, SURFLON SC-102, SURFLON SC-103, SURFLON SC-104, SURFLON SC-105, SURFLON SC-106 (above, manufactured by Asahi Glass).

[sensitizer]

The sensitizer is a function showing an increase in the amount of [B] acid generator produced, Further, the effect of improving the "apparent sensitivity" of the radiation-sensitive resin composition for immersion exposure can be exhibited. Sensitizers are listed, for example, as oxazoles, acetophenones, benzophenones, naphthalenes, phenols, diacetyl, eosin, rose red, anthraquinones, anthraquinones, phenothiazines. Wait.

<Modulation method of radiation sensitive resin composition for liquid immersion exposure>

The radiation sensitive linear resin composition for immersion exposure can be obtained by, for example, mixing [A] polymer, [B] acid generator, [C] polymer, [D] acid diffusion controlling agent, [E] solvent in a specific ratio. Modulated by any other components as needed. In this case, the resulting mixed liquid is preferably filtered through a filter having a pore diameter of about 0.20 μm. The solid content concentration of the radiation sensitive linear resin composition for liquid immersion exposure is preferably from 0.1% by mass to 50% by mass, more preferably from 0.5% by mass to 30% by mass, even more preferably from 1% by mass to 10% by mass. .

<Inductive Radiation Resin Composition>

The radiation sensitive resin composition of the present invention contains [A] a polymer having a structural unit represented by the above formula (1), [B] a radioactive acid generator, and [C] a fluorine atom content ratio [A] a polymer having a small polymer, and the [C] polymer has an acid dissociable group.

According to the radiation-sensitive linear resin composition, the surface of the photoresist film can be made to have a large back contact angle, become smaller after development, and can suppress imaging. The occurrence of defects.

<Formation method of photoresist pattern>

The photoresist pattern forming method has the steps of forming a photoresist film by using the radiation-sensitive resin composition for immersion exposure (hereinafter also referred to as "resist film formation step"), and interposing the liquid for liquid immersion exposure. a step of immersing the photoresist film in a liquid immersion process (hereinafter also referred to as "liquid immersion exposure step") and a step of developing the liquid immersion exposure photoresist film (hereinafter also referred to as "development step").

According to the photoresist pattern forming method, since the radiation sensitive resin composition for liquid immersion exposure is used, it is possible to form a photoresist pattern having less development defects while achieving high speed of scanning exposure. Hereinafter, each step will be described.

[Photoresist film forming step]

In this step, the radiation-sensitive resin composition for liquid immersion exposure is used to form a photoresist film on the substrate. As the substrate, a conventionally known substrate such as a germanium wafer or an aluminum-coated wafer can be used. Further, an organic or inorganic underlying antireflection film can be formed on the substrate as disclosed in JP-A-6-12452 or JP-A-59-93448.

The coating method is exemplified by, for example, spin coating, cast coating, roll coating, and the like. Further, the film thickness of the formed photoresist film is preferably from 10 nm to 300 nm, more preferably from 30 nm to 200 nm, still more preferably from 50 nm to 150 nm.

After applying the radiation sensitive resin composition for liquid immersion exposure, the solvent in the coating film may be volatilized by soft baking (SB) as needed. The temperature of the SB is appropriately selected depending on the composition of the radiation-sensitive resin composition for immersion exposure, but it is usually about 30 ° C to 200 ° C, preferably 50 ° C to 150 ° C. The SB time is preferably from 5 seconds to 600 seconds, more preferably from 10 seconds to 300 seconds.

[Exposure step]

In this step, the photoresist film formed in the above exposure step is subjected to liquid immersion exposure by a liquid for immersion exposure. The immersion exposure is performed by a specific mask and liquid for immersion exposure. The liquid for immersion exposure is exemplified by, for example, water, a fluorine-based inert liquid, or the like. The liquid for immersion exposure is preferably a liquid which is transparent to the exposure wavelength and which limits the deformation of the optical image projected on the film to a minimum of the refractive index temperature coefficient as small as possible. When the exposure light source is ArF excimer laser light (wavelength: 193 nm), in addition to the above viewpoints, water is preferably used in terms of ease of handling and ease of handling. When water is used, a small proportion of the additive which reduces the surface tension of the water while increasing the interfacial activity can also be added. Preferably, the additive does not dissolve the photoresist film on the wafer and is negligible for the optical coating beneath the lens. The water used is preferably distilled water.

The radiation used in the exposure is appropriately selected depending on the type of the [B] acid generator, and examples thereof include electromagnetic waves such as ultraviolet rays, far ultraviolet rays, X-rays, and γ rays; charged particle beams such as electron beams and α rays. Among these, it is preferably far ultraviolet rays, more preferably ArF excimer laser light, KrF quasi-minute Sub-laser light (wavelength 248 nm), and better ArF excimer laser light. The exposure conditions such as the amount of exposure are appropriately selected depending on the blending composition of the radiation-sensitive resin composition for liquid immersion exposure, the type of the additive, and the like. In the photoresist pattern forming method, there may be multiple exposure steps, and the same light source may be used for multiple exposures, or different light sources may be used, but ArF excimer laser light is preferably used for the first exposure.

Post-exposure bake (PEB) is preferably carried out after the above exposure. By performing PEB, the dissociation reaction of the acid dissociable group of the polymer in the radiation-sensitive resin composition for immersion exposure can be smoothly carried out. The temperature condition of PEB is preferably from 30 ° C to 200 ° C, more preferably from 50 ° C to 150 ° C. When the PEB temperature is less than 30 ° C, the above dissociation reaction may not proceed smoothly. When the PEB temperature exceeds 200 ° C, the acid generated from the [B] acid generator diffuses to the exposed portion and it is difficult to obtain a good pattern.

[development step]

In this step, the photoresist film exposed by liquid immersion in the above exposure step is developed. The developing solution is preferably such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium citrate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, Triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo[5.4 .0] An alkaline aqueous solution obtained by dissolving at least one of a basic compound such as 7-undecene and 1,5-diazabicyclo[4.3.0]-5-decene. The concentration of the alkaline aqueous solution is preferably 10% by mass or less.

The development method is exemplified by, for example, immersing the substrate in a full-fill imaging A method of immersing a liquid in a tank for a certain period of time (dipping method), a method of filling a surface of a substrate with a surface tension and developing the image for a certain period of time (liquid coating method), and spraying a developing solution on the surface of the substrate ( Spraying method) A method (dynamic coating method) in which a developing solution is applied to a substrate that is rotated at a constant speed while applying a developing solution to a developing solution coating nozzle at a constant speed.

After the above development, it is preferred to wash with a washing liquid. The washing liquid is preferably water. When the radiation sensitive linear resin composition for liquid immersion is used, since the receding contact angle after development is reduced, the developing solution and the washing liquid can be brought into good contact with the surface of the resist film, and as a result, the image formation can be effectively suppressed. The occurrence of defects.

[Examples]

The invention will be more specifically described by the following examples, but the invention is not limited to the examples. The measurement methods of various physical property values are shown below.

[ ¹ H-NMR analysis and ¹³ C-NMR analysis]

¹ H-NMR analysis and ¹³ C-NMR analysis were carried out using a nuclear magnetic resonance apparatus (JNM-ECX400, manufactured by JEOL Ltd.) using CDCl ₃ as a measurement solvent and tetramethyl decane (TMS) as an internal standard.

[Measurement of Mw and Mn]

The Mw and Mn of the polymer were measured by a gel permeation chromatography (GPC) under the following conditions.

GPC pipe column: 2 G2000HXL, 1 G3000HXL, 1 G4000HXL (manufactured by TOSOH)

Dissolution solvent: tetrahydrofuran

Flow rate: 1.0 ml / min

Column temperature: 40 ° C

Reference material: monodisperse polystyrene

Detector: differential refractometer

<Synthesis of Compounds> [Synthesis Example 1]

Feeding 1,1,1-trifluoro-2-trifluoromethyl-2,4-butanediol 120.9 g, triethylamine in a dried 1 L three-neck reactor equipped with a dropping funnel and a condenser 62.9 g and 200 mL of dichloromethane were cooled to 0 ° C in an ice bath. Next, 100.0 g of ethyl 2-(bromomethyl)acrylate was added dropwise over 30 minutes. After the completion of the dropwise addition, the mixture was stirred at room temperature for 3 hours. Subsequently, the precipitate was removed by filtration, and the reaction was quenched by adding 1 mL of 1N hydrochloric acid to the filtrate. The obtained organic layer was washed sequentially with water and saturated brine. Then, the organic layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure. Subsequently, the mixture was purified by distillation under reduced pressure, and 137.8 g (yield: 82%) of the compound represented by the following formula (S-1) was synthesized.

^{The 1} H-NMR data is shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.31 (t, 3H), 2.27-2.30 (m, 2H), 3.89-3.91 (m, 2H), 4.22-4.28 (m, 4H), 5.81 (s, 1H) , 6.37 (s, 1H).

[Synthesis Example 2]

In the same manner as in Synthesis Example 1, except that 92.7 g of methyl 2-(bromomethyl)acrylate was used instead of 100.0 g of ethyl 2-(bromomethyl)acrylate, the following formula (S-2) was synthesized. ) Compound 124.1 g (yield 77%).

The 1H-NMR data is shown below.

¹ H-NMR (CDCl ₃ ) δ: 2.29-2.32 (m, 3H), 3.90-3.93 (m, 2H), 4.23-4.30 (m, 4H), 5.83 (s, 1H), 6.35 (s, 1H) .

[Synthesis Example 3]

23.6 g, N, N'-dibromo methacrylate 1,1,1,3,3,3-hexafluoroisopropyl acrylate in a dry 1 L three-necked reactor equipped with a dropping funnel and a condenser 55.4 g of -N,N'-1,2-extended ethyl bis(2,5-dimethylbenzenesulfonamide) and 24.2 g of benzhydryl peroxide are dissolved in 1,000 mL of tetrachloroethane. Stir at room temperature for 1 hour. Subsequently, 1,000 mL of water was added to the reaction solution to terminate the reaction. The obtained organic layer was washed with saturated brine. Then, the organic layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure to give 22.0 g (yield 70%) of the precursor. Next, 1,1,1-trifluoro-2-trifluoromethyl-2,4-butanediol was fed into the dried 1 L three-necked reactor equipped with a dropping funnel and a condenser, and 14.8 g, triethyl The amine 7.1 g and 200 mL of dichloromethane were cooled to 0 ° C in an ice bath. Next, 22.0 g of the above-mentioned synthetic precursor was added dropwise over 30 minutes. After the completion of the dropwise addition, the mixture was stirred at room temperature for 3 hours. Subsequently, the precipitate was removed by filtration, and the reaction was quenched by adding 1 mL of 1N hydrochloric acid to the filtrate. The obtained organic layer was washed sequentially with water and saturated brine. Next, the organic layer was dried over anhydrous magnesium sulfate, and then concentrated under reduced pressure, and then purified by distillation under reduced pressure. 25.0 g of the compound represented by (S-3) (yield 80%).

^{The 1} H-NMR data is shown below.

¹ H-NMR (CDCl ₃ ) δ: 3.85 (S, 1H), 3.90-3.93 (m, 2H), 4.23-4.30 (m, 4H), 5.83 (s, 1H), 6.35 (s, 1H).

[Synthesis Example 4]

In Synthesis Example 1, except that 1,1,1-trifluoro-2-trifluoromethyl-2,4-pentanediol 128.9 g was used instead of 1,1,1-trifluoro-2-trifluoromethyl-2. In the same manner as in Synthesis Example 1, except that 120.9 g of 4-butanediol was used, 20.6 g (yield: 75%) of the compound represented by the following formula (S-4) was synthesized.

^{The 1} H-NMR data is shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.31 (t, 3H), 1.50 (t, 3H), 2.27-2.30 (m, 2H), 3.54 (q, 1H), 3.89-3.91 (m, 2H), 4.22 - 4.28 (m, 2H), 5.81 (s, 1H), 6.37 (s, 1H).

[Synthesis Example 5]

In Synthesis Example 3, except that 16.8 g of cyclohexyl methacrylate was used instead of 23.6 g of 1,1,1,3,3,3-hexafluoroisopropyl methacrylate, and 1,1,1-trifluoro- 15.8 g of 2-trifluoromethyl-2,4-pentanediol was used in the same manner as in Synthesis Example 3 except that 14.8 g of 1,1,1-trifluoro-2-trifluoromethyl-2,4-butanediol was used. In the operation, 27.4 g of a compound represented by the following formula (S-5) was synthesized (yield 70%).

^{The 1} H-NMR data is shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.21-1.56 (m, 10H), 2.27-2.30 (m, 2H), 3.89-3.91 (m, 2H), 4.12-4.20 (m, 1H), 4.22-4.28 ( m, 4h), 5.81 (s, 1H), 6.37 (s, 1H).

<[A] Synthesis of Polymers>

The monomer used in the synthesis of [A] polymer is shown below.

[Synthesis Example 6] (Synthesis of Polymer (A-1))

8.77 g (80 mol%) of the above compound (S-1) and 1.23 g (20 mol%) of the compound (M-2) were dissolved in 10 g of 2-butanone to further dissolve AIBN 0.42 g. Body solution. Next, a 100 mL three-necked flask having 20 g of 2-butanone was fed with nitrogen gas for 30 minutes, and then heated to 80 ° C with stirring, and the above-prepared monomer solution was added dropwise thereto over 3 hours with a dropping funnel. The polymerization reaction was carried out for 6 hours starting from the start of the dropwise addition as the start time of the polymerization reaction. After completion of the polymerization reaction, the polymerization reaction solution was cooled to 30 ° C or lower by water cooling. The cooled polymerization reaction solution was poured into 200 g of methanol, and the precipitated white powder was filtered. After the filtered white powder was washed twice with 40 g of methanol, it was filtered and dried at 50 ° C for 17 hours to obtain a white powdery polymer (A-1) (6.2 g, yield 62%). The polymer (A-1) had a Mw of 4,500 and a Mw/Mn of 1.43. As a result of ¹³ C-NMR analysis, the content ratio of the structural unit derived from (S-1) and the structural unit derived from (M-2) was 77.9 mol% and 22.1 mol%, respectively.

[Synthesis Examples 7 to 13] (Synthesis of polymer (A-2)~(A-6) and (CA-1) and (CA-2))

Each of the polymers was synthesized in the same manner as in Synthesis Example 6, except that the compound of the type and amount shown in Table 1 was used. The content ratio of each structural unit in the synthesized polymer, Mw and Mw/Mn are shown together in Table 1.

<[C] Synthesis of Polymers> [Synthesis Example 14]

43.1 g (50 mol%) of the above compound (M-1) and 56.9 g (50 mol%) of the compound (M-6) were dissolved in 100 g of 2-butanone to further dissolve AIBN 4.21 g to prepare a monomer solution. . Next, a 1,000-mL three-necked flask having 200 g of 2-butanone was fed with nitrogen gas for 30 minutes, and then heated to 80 ° C with stirring, and the above-prepared monomer solution was added dropwise thereto over 3 hours with a dropping funnel. The polymerization reaction was carried out for 6 hours starting from the start of the dropwise addition as the start time of the polymerization reaction. After completion of the polymerization reaction, the polymerization reaction solution was cooled to 30 ° C or lower by water cooling. The cooled polymerization reaction solution was poured into 2,000 g of methanol, and the precipitated white powder was filtered. After the filtered white powder was washed twice with 400 g of methanol, it was filtered and dried at 50 ° C for 17 hours to synthesize a white powdery polymer (C-1) (62.3 g, yield 62%). The polymer (C-1) had a Mw of 5,500 and a Mw/Mn of 1.41. As a result of ¹³ C-NMR analysis, the content ratio of the structural unit derived from (M-1) and the structural unit derived from (M-6) was 48.2 mol% and 51.8 mol%, respectively.

[Synthesis Examples 15 and 16]

Each of the polymers was synthesized in the same manner as in Synthesis Example 14 except that the compound of the type and amount shown in Table 2 was used. The content ratio of each structural unit of the synthesized polymer, Mw and Mw/Mn are shown together in Table 2.

<Modulation of Radiation-Resistant Resin Composition for Liquid Immersion Exposure>

The components used for the preparation of the radiation sensitive resin composition for liquid immersion exposure are listed below.

[[B]acid generator] B-1: triphenylsulfonium nonafluoro-n-butanesulfonate (compound represented by the following formula (B-1))

[[D] Acid Diffusion Control Agent]

D-1: N-third pentyloxycarbonyl-4-hydroxypiperidine (a compound represented by the following formula (D-1))

[[E]solvent]

E-1: propylene glycol monomethyl ether

E-2: cyclohexanone

E-3: γ-butyrolactone

[Example 1] (Modulation of radiation sensitive linear resin composition (J-1) for liquid immersion exposure)

5 parts by mass of (A-1) as the [A] polymer, (100 parts by mass of (C-1) as the [C] polymer, and 9.9 parts by mass of (B-1) as the [B] acid generator, (D-1) 7.9 parts by mass as the [D] acid diffusion controlling agent, and (E-1) 2,590 parts by mass, (E-2) 1,110 parts by mass, and (E-3) 200 mass as the [E] solvent The obtained mixture was filtered through a filter having a pore diameter of 0.20 μm to prepare a radiation sensitive resin composition (J-1) for liquid immersion exposure.

[Examples 2 to 8 and Comparative Examples 1 and 2] (Modulation of radiation sensitive linear resin composition (J-2)~(J-8) and (CJ-1) and (CJ-2) for liquid immersion exposure)

A radiation sensitive resin composition for each liquid immersion exposure was prepared in the same manner as in Example 1 except that each of the components shown in Table 3 and the blending amount were used.

<Evaluation>

A photoresist film was formed on the substrate by using the radiation sensitive linear resin composition for each liquid immersion exposure. The substrate was 8 turns of wafer at the measurement of the receding contact angle, and the 12-inch wafer of the lower anti-reflection film (ARC66, manufactured by Nissan Chemical Co., Ltd.) was formed when the number of development defects was measured. The following evaluations were performed for each of the formed photoresist films. The evaluation results are shown together in Table 3.

[reverse contact angle]

With respect to the formed photoresist film, the contact angle was measured in the following order using a contact angle needle (DSA-10, manufactured by KRUS) at room temperature of 23 ° C, humidity of 45%, and normal pressure.

The DSA-10 needle was washed with acetone and isopropyl alcohol before the measurement, and then water was injected into the needle to fix the wafer on which the photoresist film was formed on the wafer stage. The height of the stage was adjusted so that the distance between the surface of the photoresist film and the front end of the needle was 1 mm or less, and then water was discharged from the needle to form a water droplet of 25 μL on the photoresist film, and the water droplet was attracted by the needle at a speed of 10 μL/min. Seconds, while measuring the contact angle every second. From the time point of the contact angle stabilization, the average value of the contact angle of 20 points was calculated as the receding contact angle (°).

(after SB, the back contact angle)

After coating each immersion exposure radiation sensitive resin composition on a 8 Å wafer, SB was performed at 100 ° C for 60 seconds to form a photoresist film having a film thickness of 110 nm. The back contact angle of the surface of the photoresist film is referred to as "the back contact angle after SB".

(Retraction contact angle after development)

After each immersion exposure radiation sensitive resin composition was applied onto a 8 Å wafer, SB was applied at 100 ° C for 60 seconds to form a photoresist film having a film thickness of 110 nm. Subsequently, the image was developed by a GP nozzle of a developing device (CLEAN TRACK ACT8, manufactured by Tokyo Electronics Co., Ltd.) with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide for 30 seconds, and after washing with pure water for 15 seconds, the liquid was removed at 2,000 rpm. The surface receding contact angle of the photoresist film after drying is referred to as "retraction contact angle after development".

[Development defect number]

Each of the liquid immersion exposure radiation-sensitive resin compositions was applied onto a 12-inch wafer on which an underlying anti-reflection film (ARC66, manufactured by Nissan Chemical Co., Ltd.) was formed, and then SB was applied at 100 ° C for 60 seconds to form a film thickness of 110 nm. Photoresist film. Next, an ArF excimer laser immersion exposure apparatus (NSR S610C, manufactured by NIKON) was used to form a mask pattern with a line width of 55 nm and a line width of 55 nm with a ratio of NA = 1.3, ratio = 0.812, and dipole. The photoresist film is exposed. After exposure, PEB was carried out at 120 ° C for 60 seconds. Subsequently, it was developed with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide, washed with water, and dried to form a positive resist pattern. At this time, the exposure amount of the line and the interval of the width of 55 nm was formed as the optimum exposure amount. The optimum exposure amount is a line and a space having a line width of 55 nm formed on the entire surface of the wafer, and is used as a development defect inspection. Further, the measurement of the resist pattern was performed using a scanning electron microscope (S-9380, manufactured by Hitachi High-Technologies). The number of development defects on the wafer for inspection of the development defect obtained above was measured using a defect inspection device (KLA2810, manufactured by KLA-Tencor). The measured defects are classified into those who are judged to be from the photoresist and those from the foreign body. After the classification, the total number of persons originating from the photoresist is judged as the "number of development defects". The numerical values of the number of development defects are shown in Table 3. The development defect suppressing property of the radiation-sensitive resin composition for immersion exposure was judged as "good" when the number of development defects was less than 50/wafer, and it was judged as "bad" when it was 50/wafer or more. .

As is clear from the results of Table 3, when the radiation-sensitive resin composition for liquid immersion exposure of the Example was used, it was confirmed that the receding contact angle was larger after SB than in the comparative example, and it was found to be greatly decreased after development. It is excellent in the change in the contact angle after immersion exposure and after development. Further, according to the radiation sensitive linear resin composition for liquid immersion exposure of the examples, it was found that development defects were extremely difficult to occur.

[Industrial availability]

According to the radiation sensitive resin composition for immersion exposure and the method for forming a photoresist pattern of the present invention, it is possible to form a photoresist pattern having less development defects while achieving an increase in scanning exposure speed. Accordingly, the present invention can be preferably used in a liquid immersion exposure process, and can achieve an improvement in productivity and an improvement in the quality of the formed photoresist pattern.

Claims (5)

A radiation-sensitive resin composition containing [A] a polymer having a structural unit represented by the following formula (1), [B] a radiation-sensitive acid generator, and [C] a fluorine atom content ratio [A] a polymer having a small polymer, and the [C] polymer has an acid dissociable group, (In the formula (1), R ¹ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, R ² is a single bond, a divalent chain hydrocarbon group having 1 to 20 carbon atoms, and a divalent carbon number of 3 to 20 An alicyclic hydrocarbon group, or a combination of one or more of these and -O-, R ³ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, and R ^A is a hydrogen atom or a carbon number of 1~ 20 one-price organic base). The radiation-sensitive resin composition of claim 1, wherein, in the formula (1), R ² is one or more selected from the group consisting of a single bond and a divalent chain hydrocarbon group having 1 to 20 carbon atoms and -O - the basis of the combination. The radiation sensitive resin composition of claim 1, wherein the [A] polymer further has a structural unit containing an acid dissociable group. The radiation sensitive resin composition of claim 1, which further comprises a [D] acid diffusion control body. A photoresist pattern forming method has the following steps: a step of forming a photoresist film by the radiation-sensitive linear resin composition of claim 1, a step of immersing the liquid immersion exposure liquid with the liquid immersion exposure film, and a photo-resist film for immersing the liquid immersion film The steps.