JP2003258296A - Light-emitting element and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form an irregular structure of a nanometer size on the surface of a light-emitting element or the like, and to improve the light emission efficiency characteristics. <P>SOLUTION: Irregularities on the surface of the light-emitting element are formed as follows so that a refractive index changes smoothly from bulk. More specifically, the average diameter of the irregularities is smaller than the light wavelength (1); the pitch of the irregularities is irregular (2); the height of the irregularities and the position of a bottom surface are set to the light wavelength or less and have a variance from an average value (3). Such an element surface contains block copolymer or graft copolymer, and is obtained by forming a thin film on the surface of the light-emitting element by using a resin composition for forming a micro phase separation structure in a self organization manner, selectively removing at least one phase of the micro phase separation structure of the thin film formed on the surface, and etching the surface of the light-emitting device with the remaining phase as an etching mask. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device which realizes a high luminous efficiency characteristic by extracting light generated inside the device to the outside with high efficiency, and a manufacturing method thereof.

[0002]

2. Description of the Related Art A compound semiconductor that constitutes a light emitting element has a very high refractive index, and many light emitting elements and the like have a problem of light loss due to reflection on a surface and an interface. Therefore, it is difficult to extract the light generated inside the element to the outside. For example, a compound such as gallium phosphide (GaP) has a refractive index of about 3.5, and due to total reflection, only 19% of light can be extracted. As a countermeasure, a single layer film having a refractive index of about 1.5 is generally formed on the surface of a light emitting element or the like as an antireflection film. However, in this light emitting device, since the difference in the refractive index between the light emitting surface and the monolayer film is relatively large, it cannot be said to be sufficient.

In order to increase the light extraction efficiency, it has been studied to provide a light emitting device with a regular structure of a nanometer size so as to allow high light transmission (Non-Patent Document 1).
reference). However, the regular structure having an antireflection effect has a value close to the limit even in the photolithography using the latest excimer laser due to its nanometer size, and therefore, it has to be formed by drawing / etching with an electron beam. Therefore, the manufacturing cost is high, the productivity is poor, and it is not practical. In addition, there is no room for the process because the regular structure has to be formed in nano size.

As a technique for roughening the light emitting surface, a technique for roughening the surface by treating the surface with hydrochloric acid, sulfuric acid, hydrogen peroxide or a mixed solution thereof is generally known (patented. Reference 1 and Patent Reference 2). However, these methods are affected by the crystallinity of the substrate, and a surface that can be roughened and a surface that cannot be roughened are generated depending on the orientation of the exposed surface. Therefore, the light emitting surface cannot always be roughened, and there is a limitation in improving the light extraction efficiency.

[0005]

[Non-Patent Document 1] Applied Physics
Letters, 142, vol78, 2001, Jp
n. J. Appl. Phys. , L735, vol3
9,2000

[Patent Document 1] Japanese Patent Laid-Open No. 2000-299494

[Patent Document 2] Japanese Patent Laid-Open No. 4-354382

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to the outermost surface of the light emitting side of the semiconductor layer constituting the light emitting device or the surface of the inorganic light transmitting layer formed on the outermost layer of the light emitting side to have a nanometer size. By forming the concavo-convex structure, the light emitting efficiency characteristics of the light emitting element and the like are improved. The present invention also realizes the production of such a device having high luminous efficiency at a low production cost and high productivity.

[0007]

A first aspect of the present invention is a luminescent element.
Surface of the outermost layer on the light emitting side of the semiconductor layer constituting the child or the light
Fine on the surface of the inorganic light-transmitting layer formed on the outermost layer on the radiation side.
Is an element with various irregularities, and the surface has the following two conditions.
A light emitting element having a surface property provided
It (1) Average turning radius <R> (where
<R> = ΣR^Twon_R/ ΣRn _R, N_RIs an arbitrary turning radius
Is 1/20 or more and 1/2 of the light wavelength.
Below, and the degree of dispersion σ of the radius of gyration_R(However, σ
_R= <R> / (ΣRn _R/ Σn_R), N_RIs any rotation
The number of convex portions having a radius) is 1.05 or more and 2 or less.
To do. (2) Average height of convex and concave portions <H> (where <H> =
ΣH^Twon_H/ ΣHn_H, N_RIs a convex part with an arbitrary height
The number is 1/10 or more and 1 or less of the light wavelength, and
Dispersion σ_H(However, σ_H= <H> / (ΣHn_H/ Σn
_H), N_RIs the number of convex portions having an arbitrary height) is 1.0
Must be 5 or more and 2 or less.

A second aspect of the present invention is a resin containing a block copolymer or a graft copolymer, which is used to form a thin film on the surface of a light emitting device by using a resin composition which self-assembles a microphase-separated structure. A method for manufacturing a light emitting device, characterized in that at least one phase of the microphase-separated structure of the thin film formed on the surface is selectively removed, and the surface of the light emitting device is etched by using the rest as an etching mask. Is.

In the second aspect of the present invention, the block copolymer or graft copolymer preferably has a number average molecular weight of 100,000 or more and 10,000,000 or less.
Moreover, in the said 2nd this invention, the said resin composition is,
It is desirable that a low molecular weight homopolymer obtained by polymerizing the monomers constituting the copolymer is added to the block copolymer or the graft copolymer. Furthermore, in order to create the necessary unevenness only by dry etching, at least two kinds of polymer chains among the plurality of polymer chains forming the block copolymer or the graft copolymer should have N / N of monomer units forming each polymer chain. is the ratio of _(N C -N _O) is 1.4 or more (where, N is the total number of atoms in the monomer units, _{N C} is the number of carbon atoms of the monomer units, _{N O} is number of oxygen atoms in the monomer units) is desirable.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The principle of the present invention will be described below.

In the present invention, as a result of studying the surface structure of the light emitting device in order to improve the light extraction efficiency of the light emitting device, the following structure was found to be optimum, and the present invention was completed. . That is, the light emitting device of the present invention is a device in which fine unevenness is applied to the light emitting side outermost layer surface of the semiconductor layer constituting the light emitting device or the inorganic light transmitting layer surface formed on the light emitting side outermost layer. And the surface has a shape satisfying the following two conditions. That is, the average turning radius <R> (where,
<R> is defined as <R> = ΣR ² n _R / ΣRn _R , where n _R is defined by the number of convex portions having an arbitrary radius of gyration) is greater than 1/20 of the light wavelength and 1/2 Smaller and the degree of dispersion of the radius of gyration of the convex portion σ _R (where σ _R is σ _R =
_{<R> / (ΣRn R /} Σn R), n R is defined by the number of protrusions having any rotation radius) is 1.05 or more 2
It is the following.

In the present invention, not only visible light but also ultraviolet light can be applied as light. Therefore, the light wavelength is 300 nm or more and 80
It is appropriate that the range is 0 nm or less, and the range of the average radius of gyration is a range of 15 nm or more and 400 nm or less. Also, the average height <H> (where,
<H> is defined as <H> = ΣH ² n _H / ΣHn _H , and n _R is defined by the number of convex portions having an arbitrary height.
Greater than 10 and less than 1, and the degree of dispersion of the height of the convex portion σ _H (where σ _H is σ _H = <H> / (ΣHn _H /
Σn _H ), n _R is defined by the number of convex portions having an arbitrary height) is 1.05 or more and 2 or less.

In the present invention, the surface on which fine irregularities are formed is the outermost surface of the semiconductor layer constituting the light emitting element on the light emitting side in order to efficiently take out the light emitting from the light emitting element to the outside. , The interface where the refractive index is greatly different (for example, different by 1.5 or more) at the joint interface of a plurality of substances that form the light transmission path, the light transmission loss becomes large, so It is to provide fine irregularities. The interface is the interface between the semiconductor layer forming the light emitting element and the air layer, or the interface between the semiconductor layer and the protective film when a protective film such as plastic for protecting the light emitting element is formed. And so on.

The present invention is intended to improve the light extraction efficiency, and in order to define the surface structure, it is necessary to treat the magnitude of light reaction as a parameter. For this purpose, it is conceived that the radius of gyration of the structure is optimum, and that the light extraction efficiency can be most appropriately expressed by defining the shape of the surface irregularities by the radius of gyration of the structure. That is, the radius of the convex portion of the surface structure of the present invention is defined by the radius of gyration. And, even if various different shapes have the same radius of gyration, the operation of the present invention becomes equal. The radius of gyration is defined by RIKEN 5th edition (Iwanami Shoten).
There is a description in.

In the present invention, the radius of gyration of the convex portion is defined as follows. That is, with respect to the uneven surface, the highest convex portion is surrounded by the lowest concave portion in a circular shape. Specifically, the concave portion is drawn around the apex of the convex portion from the concave-convex image obtained by the intermolecular force microscope.
Image processing is performed on this portion to determine the center of gravity. The radius of gyration is calculated by calculating the moment by converting the distance from the center of gravity to the concave portion, which is defined as R. The radius of gyration of these structures can be determined by a known light scattering method. That is, if the scattered vector is q, the scattered light intensity I (q) is measured, and if lnI (q) is plotted against q ² , the radius of gyration can be obtained from the inclination (Guinier plot: reference material). "Polymer Alloy" edited by The Polymer Society of Tokyo, Tokyo Kagaku Dojin, 1981 73
See page). In addition, since this scattered image measures the correlation in Fourier space, the radius of gyration can be obtained by the Fourier transform of the electron microscope image as well (see Reference: Rikagaku Dictionary 5th Edition (Iwanami Shoten)). ).

In the surface structure that causes light scattering, the larger the size of the surface structure, the greater the influence on light, and the effect is proportional to the square of the size. Therefore, the average radius of gyration <R> is 1/2 of the wavelength of the light emitted from the light emitting element.
It is preferably 0 or more. Average turning radius <R>
However, if it is smaller than this, it goes out of the Rayleigh scattering region, and the effect of the unevenness is rapidly lost. A more preferable range is about 1/10 or more of the wavelength of light. In addition, when the average radius of gyration <R> is large and is about 1/2 of the wavelength level of light, that is, when it becomes equivalent to light, the light comes to recognize the shape of the unevenness itself, and therefore the refractive index gradient (gradient index). The effect of is lost, which is not preferable. Further, the average radius of gyration <R> is preferably about 1/4 or less of the wavelength of the light, which is a size at which the light does not recognize the shape of the unevenness.

Further, various kinds of large particles are formed on the surface of the light emitting device of the present invention.
It is characterized by the presence of unevenness in the texture. I.e. the book
The surface of the light-emitting device of the invention has a completely uniform size of irregularities.
It is convenient not to do so. The reason is as follows
It That is, with a certain size of the uneven structure of the object surface
Is known to scatter light with a certain scattering angle
There is. The angle dependence of the scattered light intensity at this time is
It is described by the sel function. Φ (u) = (3 / u^Three) [Sin (u) -ucos
(U)] And is the scattered light from the aggregate the sum of these?
Therefore, from the structure that is aligned in a specific size, it can be scattered at a specific angle.
The result is a disturbance. At this time, depending on the size of the structure
Given the degree of distribution, the distribution function folds into these scatters.
Included (Convolution: see Iwanami Shoten, the dictionary of science and chemistry)
Therefore, scattering does not appear at a specific angle.
It From a different point of view, this is due to the reflection of light at the surface interface.
It also means that there is no wavelength dependence. The present invention as described above
As a condition for obtaining the structure of the surface where the effect of
Is σ _R= <R> / (ΣRn_R/ Σn_R) Defined by
Depends on the degree of dispersion. Where n _RHas a size of R
It is the number of structures. This dispersity is 1.05 or more
And convolve with the above Bessel function
If there are no scattered light valleys for the scattering angle,
Turned out to be appropriate. However, this value is 2
When it crosses over, it becomes a random structure,
It was found that the stopping power was significantly reduced.

The same argument applies to the height.
Maru The size of the structure of the present invention is smaller than the wavelength of light.
Therefore, the light does not feel the individual irregularities, but the average value.
It Therefore, the light emitting layer having a high refractive index and the medium having a low refractive index
When there is, the refractive index that light feels is uneven
Is the average value of the refractive index on a plane parallel to. This refraction
The average value of the rate decreases smoothly from the light emitting layer and reaches the outside
Is desirable. To obtain a gradient of such a refractive index
The top and bottom surfaces of the unevenness, that is, the height is
It is desirable to have some variation rather than This
As the structure of the light emitting element surface,
Uniform height <H> (where <H> = ΣH^Twon _H/ ΣH
n_H) Is larger than 1/10 of the light wavelength and smaller than 1.
The degree of dispersion σH (where σ_H= <H> /
(ΣHn_H/ Σn_H)) Is 1.05 or more and 2 or less
It is necessary. Also, add a gradient of refractive index
In order to remove the unevenness, it is desirable that the shape of the unevenness is close to a conical shape.
The average height is defined by the root mean square structure.
Is the result of weighting to react to. Average height
<H> is preferably 1/10 or more of the wavelength of light. Less than this
Otherwise, the refractive index will change over a very short distance.
Is no longer effective as a gradient index
This is the same principle as the above-mentioned turning radius,
The effect of disappears rapidly. The effect of unevenness is
Since it works with the square of the size, the average value is required to keep the effect of the present invention.
The height should be about 1/5 of the wavelength of light or more.
Yes. On the other hand, if the average height is too high, the refractive index gradient (gradient
The effect of the Student Index) disappears. So
Therefore, the average height is the height at which the light does not recognize the uneven shape.
The desired wavelength is about 1/2 or less of the wavelength of light.

As described above, a fine uneven structure in which the size of the required uneven pattern is not more than the wavelength of light and which must not be completely random while having some irregularity is artificially formed. And it is extremely difficult to form economically. As a result of studying in consideration of such a point, it was found that it can be realized by utilizing the self-organizing force existing in nature. In order to realize such a self-organizing force in the natural world, we have completed the method for producing a light-emitting device of the present invention, focusing on the fact that the method using a block copolymer developed by the present inventors can be easily achieved ( See JP-A-2000-100419). in this way,
The use of the self-assembly pattern of block copolymers makes it easy to adapt because it does not require a large capital investment such as exposure equipment using an excimer laser or electron beam lithography equipment, and the equipment and processes used for compound semiconductors can be used as they are. Is.

Embodiments of the present invention will be described below.

[Light Emitting Element] The light emitting element of the present invention is a semiconductor light emitting element such as a light emitting diode (LED) or a semiconductor laser (LD). An example of this light emitting element is shown in FIG. In the figure, 10 is an n-type GaP substrate, and this substrate 1
0, a heterostructure portion 14 including an n-type InAlP clad layer 11, an InGaP active layer 12, a p-type InAlP clad layer 13 and the like is formed, and a p-type GaP current diffusion layer 15 is formed thereon. A p-side electrode (upper electrode) 16 is formed on a part of the current diffusion layer 15, and an n-side electrode (lower electrode) 17 is formed on the back surface side of the substrate 10.
The emitted light in the active layer 12 is taken out from the surface of the current diffusion layer 15 on which the electrode 16 is not formed. The basic structure up to this point is substantially the same as that of the conventional element, but in addition to this, in the present embodiment, the current spreading layer 1
No. 5 electrode 16 is not formed on the exposed surface
Are formed. The uneven structure of this surface is a surface having the above-mentioned average radius of gyration and average height. An inorganic light transmitting layer (not shown) having a refractive index equal to that of the current diffusing layer is further formed on the exposed surface of the current diffusing layer 15 on which the electrode 16 is not formed, and fine irregularities are formed on the surface of the inorganic light transmitting layer. May be formed. It is better to form the fine irregularities directly on the exposed surface of the current diffusion layer 15 on which the electrode 16 is not formed, because of the simplicity of the process and the high light extraction efficiency.

[Method for Manufacturing Light-Emitting Element] Next, a method for manufacturing such a light-emitting element will be described. First, Fig. 2 (1)
As shown in FIG. 1, the hetero structure 1 is formed on the n-GaP substrate 10.
4 and the current diffusion layer 15 are epitaxially grown, the p-side electrode 16 is formed on a part of the current diffusion layer 15, and the n-side electrode 17 is formed on the back surface side of the substrate 10. Is the same. Then, as shown in FIG. 2 (2), a solution of a block copolymer, which is a microphase-separated structure composition, dissolved in a solvent is spin-coated on the substrate shown in FIG. Then, the mask material layer 21 is formed by evaporating the solvent.
Then, annealing is performed in a nitrogen atmosphere to perform phase separation of the block copolymer. Then, the block-copolymer of the phase-separated film is etched by performing RIE on the phase-separated substrate with the block copolymer, under an etching gas flow. At this time, the phase of any one of the polymer fragments is selectively etched due to the difference in the etching rate of the plurality of polymer fragments forming the block copolymer. Therefore, as shown in FIG.
Remains. Then, as shown in FIG. 2 (4), the pattern 2 of the polymer fragment left without being removed by etching.
RIE with 2 as a mask and the required etching gas
Then, the fine concavo-convex pattern 1 is formed on the surface of the current diffusion layer 15.
8 is formed. Not only Cl ₂ but also BCl ₃ , N ₂ or Ar gas is used as the gas to be used for etching. After that, the remaining polymer fragment is removed by an O ₂ asher to obtain the structure shown in FIG. 1 (FIG. 2 (5)).

[Micro-Phase Separation Structure-Forming Resin Composition] As described above, in the present invention, a thin film of a block copolymer or a graft copolymer is formed for micro phase separation (phase separation within the molecule of the block copolymer). Thereafter, one polymer phase is selectively removed, thereby forming a porous film having a nanometer-sized pattern. The obtained porous film can be used as a mask for etching the base and transferring the pattern. In the present invention, in order to selectively remove one polymer phase from the microphase-separated structure, a difference in dry etching rate between the two polymer phases and a difference in decomposability with respect to energy rays,
Alternatively, the difference in thermal decomposability is used. In either method, since it is not necessary to use a lithography technique, the throughput is high and the cost can be reduced.

First, the block copolymer or graft copolymer will be described. The block copolymer refers to a linear copolymer in which a plurality of homopolymer chains are linked as a block. Typical examples of block copolymers are
A polymer chain having repeating unit A and repeating unit B
A B polymer chain having a
It is an AB type diblock copolymer having a structure of (AA ... AA)-(BB ... BB)-. A block copolymer in which three or more types of polymer chains are bonded may be used. In the case of triblock copolymer, ABA type, B
Any of -AB type and ABC type may be used. A star-type block copolymer in which one or more polymer chains extend radially from the center may be used. 4 blocks
One or more block copolymers such as (AB) n type or (ABA) n type may be used. The graft copolymer has a structure in which a polymer main chain hangs from another polymer chain as a side chain. In the graft copolymer, several kinds of polymers can be hung on the side chain. Further, a combination of a block copolymer and a graft copolymer in which a C polymer chain is hung in an AB type, ABA type, BAB type block copolymer or the like may be used.

The block copolymer is easy to obtain a polymer having a narrow molecular weight distribution as compared with the graft copolymer,
It is preferable because the composition ratio can be easily controlled. In addition, although the block copolymer is often described below, the description about the block copolymer can be applied to the graft copolymer as it is. Block copolymers and graft copolymers can be synthesized by various polymerization methods. The most preferred method is the living polymerization method. In the living anionic polymerization method or the living cationic polymerization method, a block copolymer can be synthesized by initiating polymerization of one type of monomer with a polymerization initiator that generates an anion or cation and sequentially adding other monomers. . As the monomer, for example, a monomer having a double bond such as a vinyl compound or butadiene, a cyclic ether monomer such as ethylene oxide, or a cyclic oligosiloxane monomer is used. A living radical polymerization method can also be used. In the living polymerization method, the molecular weight and the copolymer ratio can be precisely controlled, and a block copolymer having a narrow molecular weight distribution can be synthesized.
When the living polymerization method is used, it is preferable to sufficiently dry the solvent with a desiccant such as sodium metal and to prevent oxygen contamination by a method such as freeze-drying or bubbling with an inert gas. The polymerization reaction is preferably carried out under an inert gas stream, preferably under a pressurized condition of 2 atm or more. The pressurizing condition is preferable because it is possible to effectively prevent mixing of water and oxygen from the outside of the reaction vessel and to carry out the reaction process at a relatively low cost.

The chemical bond connecting the polymer chains is preferably a covalent bond from the viewpoint of bond strength, particularly carbon-
More preferably, it is a carbon bond or a carbon-silicon bond. Block copolymers and graft copolymers are mainly used at the laboratory level because they require more equipment and skills than general radical polymerization methods, and their industrial application is very limited in terms of cost. .. However, in the field of manufacturing high value-added products such as the electronics industry, even block copolymers and graft copolymers can be sufficiently cost-effective.

Flory-Haggins
According to the theory of Ggins), generally, the free energy Δ of mixing is required for phase separation of A polymer and B polymer.
G must be positive. It is difficult for the A polymer and the B polymer to be compatible with each other, and when the repulsive force between the two polymer chains is strong, phase separation is likely to occur. Further, since the larger the degree of polymerization of the block copolymer is, the more easily microphase separation occurs, the molecular weight has a lower limit value. However, the polymers of each phase forming the phase-separated structure do not necessarily have to be mutually incompatible. If the precursor polymers of these polymers are incompatible with each other, a microphase-separated structure can be formed.
After forming a phase-separated structure using a precursor polymer, it can be converted into a target polymer by reacting by heating, light irradiation, catalyst addition, or the like. At this time, if the reaction conditions are appropriately selected, the phase-separated structure formed by the precursor polymer is not destroyed. Phase separation is most likely to occur when the composition ratio of the A polymer and the B polymer is 50:50. This means that the microphase-separated structure that is most easily formed is the lamella structure. Conversely, it may be difficult to make the composition of one polymer very high to form a sea-island structure containing small islands of the other polymer. Therefore, the molecular weight of the block copolymer is an important factor in obtaining the desired microphase-separated structure.

In the present invention, in order to pattern the size of a nanometer-sized structure, one having a higher molecular weight than a usual block polymer is used. Therefore, the necessary molecular weight is such that the number average molecular weight is 100,000 or more and 10 million or less. This means that the block copolymer or graft copolymer of claim 3 has a number average molecular weight of 100,000 or more 1
It is a manufacturing method characterized by using a block copolymer or a graft copolymer characterized by being 10 million or less. At this time, if the molecular weight is less than 100,000, the size required by the method of the present invention will not be sufficiently reached. If it is more than 10 million, the viscosity will be so high that it will be impossible to form a structure in a self-organizing manner.
Therefore, a desired pattern cannot be obtained. In the present invention, after obtaining the self-assembled pattern, the substrate is processed by using etching. Since it is difficult to obtain a pattern in which the self-assembled pattern is larger in the vertical direction than in the horizontal direction with respect to the substrate, if the molecular weight is small and the self-assembled structure is small, the film thickness of the polymer film becomes thin accordingly. I will end up. Therefore, if the pattern formed by self-organization is small, it is necessary to use a thin etching mask, which makes the etching process difficult. Therefore, when the molecular weight is larger than 400,000, etching becomes easier. Further, the polymer of the present invention is generally synthesized by the living anion polymerization method. For this reason, they dislike water and oxygen very much. However, the monomer contains some water and oxygen, and it is very difficult to completely remove it. Therefore, it is very difficult to polymerize a polymer having a molecular weight of 3,000,000 or more.
Further, if the molecular weight exceeds 3,000,000, the viscosity of the polymer when it is made into a solution is so high that the concentration of the solvent cannot be sufficiently increased. Therefore, uneven coating may appear during application and drying.

However, it is very difficult to polymerize the block copolymer by strictly controlling the molecular weight. Therefore, the molecular weight of the synthesized block copolymer was measured,
One of the homopolymers may be blended so that the desired composition ratio is obtained, and the composition ratio may be adjusted. The amount of the homopolymer added is 100 with respect to 100 parts by weight of the block copolymer.
The amount is set to not more than 50 parts by weight, preferably not more than 50 parts by weight, more preferably not more than 10 parts by weight. If the amount of the homopolymer added is too large, the microphase-separated structure may be disturbed.

If the two polymers constituting the block copolymer have too large a difference in solubility, phase separation between the AB block copolymer and the A homopolymer may occur.
In order to avoid this phase separation as much as possible, it is preferable to lower the molecular weight of the A homopolymer. This is because when a homopolymer having a small molecular weight is blended, the negative value of the entropy term in the Flory-Huggins equation becomes large,
This is because it becomes easy to mix the AB block copolymer and the A homopolymer. The molecular weight of the A homopolymer is thermodynamically stable when it is smaller than that of the A block in the block copolymer. Considering thermodynamic stability, the molecular weight of the A homopolymer is more preferably smaller than 2/3 of the molecular weight of the A polymer forming the AB block copolymer. On the other hand, if the molecular weight of the A homopolymer is less than 1000, it may be dissolved in the B polymer of the AB block copolymer, which is not preferable. Further, considering the glass transition temperature, the molecular weight of A homopolymer is more preferably 3000 or more. Details of the technique relating to the adjustment of the composition ratio of these block copolymers and the prevention of phase separation will be described later.

Examples of the microphase structure-forming resin composition used in the present invention will be described below. First, a microphase structure-forming resin composition composed of a block copolymer or a graft copolymer containing two or more kinds of polymer chains having a large difference in dry etching rate will be described. The microphase structure-forming resin composition of the present invention has a value of N / (Nc-No) of each monomer unit (where N is the total number of atoms of the monomer unit, Nc is the number of carbon atoms of the monomer unit, No. Contains a block or graft copolymer having two polymer chains with a ratio of the number of oxygen atoms in the monomer units of 1.4 or more. The requirement that the ratio of the N / (Nc-No) values for the two polymer chains is 1.4 or more means that the etching selectivity of each polymer chain forming the microphase-separated structure is large. That is, when the microphase-structure-forming resin composition satisfying the above requirements is microphase-separated and then dry-etched, one polymer phase is selectively etched and the other polymer phase remains.

Below, the parameter N / (Nc-No)
Will be described in more detail. N is the polymer
Total number of atoms per segment (equivalent to monomer units),
Nc is the number of carbon atoms, and No is the number of oxygen atoms. This para
The meter is a finger indicating the dry etching resistance of the polymer.
The larger the value, the more dry etching
Higher etching rate (dry etching resistance
descend). That is, the etching rate Vetch and the above
Between the parameters Vetch∝N / (Nc-No) There is a relationship. This tendency is due to Ar, O_Two, CF_Four,
H_TwoAlmost depends on the type of various etching gas such as
No (J. Electrochem. Soc., 13
0,143 (1983)). As the etching gas,
Ar, O described in the above documents_Two, CF_Four, H_Two
Besides, C_TwoF₆, CHF_Three, CH_TwoF _Two, CF_Three
Br, N_Two, NF_Three, Cl_Two, CCl_Four, HBr, SF
₆Etc. can be used. Note that this parameter
And etching of inorganic materials such as silicon, glass and metal
Has nothing to do with. Refer to the chemical formula below for specific parameters.
Calculate the meter value. Polystyrene (PS) monomer
ー Unit is C₈H₈Therefore, 16 / (8-0) = 2.
It The monomer unit of polyisoprene (PI) is C₅H₈
Therefore, 13 / (5-0) = 2.6. Polymeta
The monomer unit of methyl acrylate (PMMA) is C₅O_Two
H₈Therefore, 15 / (5-2) = 5. According to
In the block copolymer of PS-PMMA,
High etching resistance, only PMMA is etched
It can be expected to be easy. For example, CF_Four30 scc
Flow at a flow rate of m, and pressure is 1.33 Pa (0.01 Tor
r), traveling wave 150W, reflected wave 30W
When reactive ion etching (RIE) is performed in
PMMA shows several times faster etching rate than PS
It has been confirmed that

Thus, a nanostructure-forming composition containing a block or graft copolymer suitable for use in the present invention, forming a microphase-separated structure, which constitutes said block or graft copolymer. for at least two polymer chains of the plurality of polymer chains, the ratio is 1.4 or more N / monomer units constituting each polymer chain (N C _{-N O)} (however, N is the total of the monomeric units The number of atoms, N _C is the number of carbon atoms in the monomer unit, and N _O is the number of oxygen atoms in the monomer unit.) A microphase-separation-forming resin composition can be obtained. Further, using this, at least one phase of the micro phase separation structure formed in the molded body by dry or wet etching is selectively removed, and the porous structure having the micro phase separation structure is retained. Can be formed.

[Improved Micro-Phase Separation Structure-Forming Resin Composition] Using the above-mentioned micro-phase separation structure-forming resin composition, the above-mentioned method for producing a light-emitting device can be found in Examples described later. It becomes clear that it is possible to manufacture a device having such an excellent emission light rate. However, the molecular weight of the block copolymer used in the resin composition capable of forming a microphase-separated structure is very high. Therefore, it takes a long annealing time to form the microphase-separated structure (intramolecular phase-separated structure) of the block copolymer. I need. Further, it cannot be said that the microphase-separated structure after the annealing has a sufficiently regular structure, and there is room for further improvement.

The inventors of the present invention have conducted various studies in order to solve these problems, and as a result, the addition of a low molecular weight homopolymer to an ultrahigh molecular weight block copolymer dramatically shortens the annealing time. Found. It was also confirmed that the regularity of the structure after annealing was improved.

That is, the improved resin composition capable of forming a microphase-separated structure is a composition obtained by adding a low molecular weight homopolymer to the block copolymer or the graft copolymer. This low molecular weight homopolymer is preferably one homopolymer of a plurality of monomers constituting the block copolymer or the graft copolymer. The desirable low molecular weight homopolymer has a molecular weight of 1,000 or more and 30,000 or less. If the molecular weight of this low molecular weight homopolymer is below 15,000,
The desired phase separation pattern cannot be obtained due to the phenomenon of phase separation due to the difference in solubility between the above-mentioned two polymers. Due to the phenomenon of macroscopic phase separation between polymers, the desired effect is not exerted either.

As the low molecular weight homopolymer, PS copolymers such as block copolymers or graft copolymers can be used.
When a PMMA copolymer is used, any one of PS homopolymer and PMMA homopolymer, or a mixture thereof can be used. Similarly PS
When the -PI copolymer is used, any one of PS homopolymer and PI homopolymer, or a mixture thereof can be used.

The details of the improved microphase-separated structure-forming resin composition will be described below. In the graded index (GI) processing for processing the LED surface using the block copolymer of the present invention into a shape such that the average turning radius and average height of the surface irregularities of the present invention are in the optimum range, the annealing time of the block copolymer is changed. Length is a problem. This is because a dot pattern with a diameter of about 100 nm is convenient for GI processing, but this requires the use of a block copolymer having a very high molecular weight. For example, in order to form a concavo-convex pattern having a diameter of about 110 nm, an ultra high molecular weight block copolymer having a molecular weight of polystyrene (PS) of about 300,000 and a molecular weight of polymethylmethacrylate (PMMA) of about 800,000 was required. As described above, when the molecular weight of the entire polymer exceeds 1,000,000, the annealing time required for self-assembly is extremely long. This is because the polymer main chain moves because the microphase-separated structure is generated by self-assembly.
This is because the polymer needs to be aggregated with the A polymer and the B polymer with the B polymer to form a domain. However, an increase in the molecular weight of the polymer means an increase in the molecular chain, that is, an increase in the probability of entanglement of the polymer chains. A physical verification of the effect of this entanglement is given in P. de Genenes
No Scaling Concept in Polymer
r Physics (CornellUnivers
ty Press 1979) (Japanese translation: Physics of polymers by De Jean, Yoshioka Shoten). This is because, basically, by increasing the molecular weight, the entanglement points of the chains rapidly increase, and accordingly, the polymer chains are bound to each other and cannot move, and the progress of self-assembly during annealing remarkably slows down. This was a problem peculiar to ultra-high molecular weight compounds such as block copolymers designed for making GI. In addition, since it is an intrinsic problem of the molecule, it seems that long annealing time cannot be avoided.

However, the inventors thought that the viscosity could be lowered by reducing the number of entanglement points. However, it is impossible to reduce the molecular weight in order to reduce the entanglement points, because the size of the phase separation structure becomes small. Therefore, in the present invention, a phase-separated structure formed by an AB block copolymer in which one polymer has a spherical structure is used. At this time, in the AB block copolymer, A
If the B polymer is shorter than the lengths of the polymer and the B polymer, the B polymer becomes a minor phase and forms a spherical domain. The size of the spherical structure formed by this minority phase B polymer is important. Therefore, the entanglement points are reduced by reducing only the molecular weight of the A polymer without changing the molecular weight of the B polymer. However, in this method, the shape of the structure formed by the B polymer is changed, and this can be solved by adding the A homopolymer.
As a result, a pattern having a diameter of 100 nm or more can be formed without synthesizing an ultrahigh molecular weight block copolymer. However, it is difficult to synthesize a high molecular weight polymer by the living polymerization method. Therefore, the B homopolymer can be added in addition to the A homopolymer. At this time, if the ratio of the A component and the B component among the A-B block copolymer, the A homopolymer, and the B homopolymer is always kept constant, the pattern having the same shape can be obtained. In this case, however, the addition of the minority phase A homopolymer deteriorates the regularity of the pattern. Therefore, the addition amount is preferably 10% or less of the total polymer amount by weight.

However, there is a problem peculiar to the present technology caused by using the ultra-high molecular weight block copolymer. According to the theory of Flory Haggins, the entropy decreases at high molecular weight, so the repulsive force becomes relatively strong. Therefore, repulsive force acts between the A-B block copolymer and the A homopolymer or B homopolymer, causing macroscopic phase separation of about several μm. In such a case, a salami-like structure such as that found in SBS rubber appears. For this reason, the micro image separation structure of the size of about 100 nm that we need cannot be formed.

In order to solve this, it has been found that it is necessary to reduce the molecular weight of the A homopolymer to such an extent that the repulsive force does not act on the AB block copolymer. By taking such a measure, the A homopolymer dissolves in the A phase of the AB block copolymer for the first time, and it is as if
-A Miku phase-separated structure, which the B block copolymer alone forms, is generated.

Recently, block copolymers can be synthesized by the living radical polymerization method. This polymerization method is easier to synthesize than the living anion method, but has a drawback that the molecular weight distribution is wide.
As a result of examining the polymer synthesized by this polymerization method, we were able to obtain an unexpected finding regarding the molecular weight distribution.

Polymerization by the living anion method makes it possible to obtain a polymer having a narrow molecular weight distribution. When a low molecular weight homopolymer is added to the block copolymer polymerized by this method, the molecular weight peak naturally becomes 2 as shown in FIG.
Become one When the molecular weight distribution is measured as if it were one kind of polymer, Mw / Mn which is the standard of the molecular weight distribution
The value of (weight average molecular weight / number average molecular weight) becomes large.
However, if the molecular weight of the homopolymer is small enough, A
Microphase separation occurs between B and B, resulting in domains of fairly uniform size.

On the other hand, the polymer prepared by the living radical method has a wide molecular weight distribution and a large value of Mw / Mn. When this was made into a thin film and observed by patterning, it was found that domains of various sizes were formed and a circular pattern of uniform diameter could not be formed. this is,
Although the polymers with various molecular weights are mixed, it is considered that the distribution of the sizes of the generated domains was possible because the molecular weights were different depending on the locations because they were not mixed uniformly.

As described above, it was found that even with a polymer having a large Mw / Mn, there is a large difference in the results between the block polymer prepared by the radical polymerization method and the composition of the present invention. From the above results, it was found that the present invention exhibits its effect only under the following conditions. That is, it is a composition in which a multi-phase A or B homopolymer having a sufficiently low molecular weight is mixed with an ultrahigh molecular weight AB block copolymer in which the molecular weight of A is larger than B.

Here, the average molecular weight of the AB block copolymer is very large, specifically, 300,000 or more. The molecular weight distribution is narrow, and Mw / Mn is 1.2 or less. The molecular weight of the homopolymer added to this should be 1/10 or less of that of the AB block copolymer.
This homopolymer need not be a narrow dispersion polymerized by the living anion method, but may be one polymerized by the radical method.

The inventors have found the following facts during further study. In general, if you want to create a flawless structure, you obviously need to create one. Also in the present technology, in order to obtain a pattern of the block copolymer having the highest regularity, Mw
Polymers with a uniform molecular weight of / Mn close to 1 have been synthesized. In fact, in the block copolymer for a hard disk disclosed by the inventors in JP 2001-151834 A, a highly regular pattern can be obtained by using a block polymer having a narrow molecular weight distribution.

However, the ultra-high molecular weight polymer has many entanglement points, and it is impossible to obtain a perfect ordered structure in a finite time. For this reason, the structure to which the low molecular weight homopolymer is added is formed earlier, for example, 10
It was found that the regularity was improved when the annealing time was realistic. Therefore, the present invention is also effective for enhancing the regularity of the phase separation structure formed by the ultra-high molecular weight block copolymer having a molecular weight of 300,000 or more.

[Formation of Micro-Phase Separation Structure-Forming Composition Thin Film] To form a thin film of the micro-phase structure-forming resin composition of the present invention, a uniform solution of the above resin composition is applied to the surface of the light emitting device. Is preferred. If a uniform solution is used, it is possible to prevent the history of film formation from remaining. If the coating solution is non-uniform due to the formation of micelles with a relatively large particle size in the solution, an irregular phase separation structure mixes in, making it difficult to form a regular pattern or creating a regular pattern. It is not preferable because it takes time to form.

The solvent for dissolving the block copolymer which is the resin composition for forming a microphase structure of the present invention is preferably a good solvent for the two kinds of polymers constituting the block copolymer. The repulsive force between polymer chains is proportional to the square of the difference in solubility parameter between two polymer chains.
Therefore, if a good solvent for two types of polymers is used,
The difference in the solubility parameter of the polymer chains of the seed becomes small, and the free energy of the system becomes small, which is advantageous for phase separation. When making a thin film of block copolymer,
So that a homogeneous solution can be prepared
Ethyl cellosolve acetate (ECA), propylene glycol monomethyl ether acetate (PGME
It is preferable to use a solvent having a high boiling point such as A) or ethyl lactate (EL). The thickness of the formed microphase-separated structure-forming composition thin film is preferably in the range of 2 to 3 times the radius of gyration of the target surface irregularities. If this film thickness deviates from this range, it is difficult to obtain an uneven structure having a desired average radius.

[Formation of Micro Phase Separation Structure] The micro phase separation structure of the block copolymer or graft copolymer can be prepared by the following method. For example, a block copolymer or a graft copolymer is dissolved in a suitable solvent to prepare a coating solution, and the coating solution is coated on a substrate and dried to form a film. A good phase separation structure can be formed by annealing this film at a temperature not lower than the glass transition temperature of the polymer. The copolymer may be put in a molten state, annealed at a temperature of not less than the glass transition temperature and not more than the phase transition temperature to cause microphase separation, and then the microphase separation structure may be fixed at room temperature. It is also possible to form a microphase-separated structure by slowly casting a solution of the copolymer. By melting the copolymer, by hot pressing, injection molding, transfer molding, etc.
After being formed into a desired shape, it can be annealed to form a microphase-separated structure. Means for forming a nanometer-sized structure using the microphase-separated structure thus formed is described in detail in Japanese Patent Application Laid-Open No. 2000-100419 filed by the present inventors. Therefore, this means can also be adopted in the present invention.

The pattern transfer method is also an effective method in the present invention. The details are described in Japanese Patent Application Laid-Open No. 2000-100419 filed by the present inventors, and this means can also be adopted in the present invention. Specifically, a layer having a different etching resistance (pattern transfer layer) is applied on a substrate of a compound semiconductor, and then the block copolymer layer of the present invention is applied. At this time, the pattern transfer layer may include SOG.
(Spin-on-glass) and JP-A-2000-1004
Materials such as those shown in No. 19 can be used. The block copolymer layer is dry or wet etched to selectively remove only one phase of the block copolymer to form an uneven pattern. Next, the pattern transfer layer is etched using the organic polymer pattern as a mask. For example, when a fluorine-based gas, a chlorine-based gas, or a bromine-based gas is used, the pattern transfer layer such as SOG can be etched using the organic material as a mask. Such a microphase separation pattern of the resulting block copolymer can be transferred to the pattern transfer layer. Next, the substrate is etched using the pattern transfer layer to which this pattern is transferred as a mask. Such a method
It is effective for etching a compound containing a metal that cannot have an etching selection ratio with a carbon-based polymer material.
Further, by using a plurality of pattern transfer layers,
It is also possible to stack materials having different etching resistances to obtain a pattern having a high aspect ratio.

[0053]

EXAMPLES (Reference Example) The following reference experiment was conducted in order to verify the relationship between the condition of the uneven structure of the light emitting surface of the present invention and the luminance effect. That is, in order to explore the effect of shape, various patterns were prepared on the light emitting surface of the GaP substrate. Since it is very difficult to synthesize block copolymers according to each pattern, electron beam drawing was used instead. In this experiment, an electron beam resist (FEP-301 manufactured by Fuji Film) was used as a model system, and a nanometer-order pattern was generated by an electron beam exposure apparatus equipped with a pattern generator and having an acceleration voltage of 50 kV. Since an arbitrary pattern can be obtained by using this exposure apparatus, a desired pattern can be obtained in terms of size and size distribution. Further, the electron beam resist used here uses polyhydroxystyrene as a base polymer, and since the resistance to dry etching is close to that of polystyrene, almost the same etching shape as the pattern using the block copolymer can be reproduced. The substrate was etched under the same conditions as in Example 3. In addition,
The emission wavelength of this device was 650 nm.

The effect on brightness due to the difference in pattern size was measured. The value is compared with the reference value 1 as a value in which no unevenness is formed on the light emitting layer surface. The size of the pattern is represented by 2 <R>, which is twice the average value of the radius gyrations. The results are shown in Table 1.

[0055]

[Table 1]

As is clear from the results shown in Table 1, the luminance effect increases as 2 <R> increases. This is because the light responds to the size of the pattern. However, it was observed that the scattered light increased as the pattern became larger from the wavelength range. In particular, it was observed that the amount of light emitted vertically from the surface of the device decreased and the brightness decreased. From the above results, wavelength 650n
The average radius of gyration <R> which is preferable in the present invention when light of m is
It was found to be 25 nm or more and 250 nm or less (diameter is 50 nm or more and 500 nm or less).

Next, the effect on the brightness due to the difference in the pattern size distribution was measured. The pattern size is 11
Those of 0 nm and 200 nm were used. The value of the brightness effect is
The light emission value of a sample having no unevenness size distribution on the surface of the light emitting layer was used as a reference value 1 for comparison. The results are shown in Table 2.

[0058]

[Table 2]

As is clear from the results shown in Table 2, the effect of luminance increases as the distribution increases even if the pattern size is the same. However, when the distribution became too large, the brightness decreased.

Next, the effect on the brightness due to the difference in pattern height was measured. The value of the brightness effect is compared by using the value in which no unevenness is formed on the surface of the light emitting layer as the reference value 1. The results are shown in Table 3.

[0061]

[Table 3]

As is clear from the results in Table 3, the effect on luminance increases as <H> increases. This is because the gradient of the refractive index is being created as the value increases. However, when the height of the pattern became larger than the wavelength, it was observed that the surface of the light emitting layer became cloudy. Because of this, scattering was occurring strongly. In particular, it was observed that the light emitted vertically from the device surface became very small.

Next, the effect on the brightness due to the difference in the distribution of the pattern heights was measured. The light emission value of the sample having no unevenness height distribution on the light emitting layer surface was used as the reference value 1 for comparison. The results are shown in Table 4.

[0064]

[Table 4]

As is clear from the results shown in Table 4, the effect of luminance increases as the distribution increases even if the pattern height is the same. It is considered that this is because the heights of the patterns are not uniform and, conversely, a gradient of the refractive index can be formed. But if the distribution is too large,
There was a tendency that the amount of scattering suddenly increased and the brightness decreased.

The present invention will be further described below with reference to examples. In this embodiment, the diameter is twice the radius of gyration. (Embodiment 1) An embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 2A, a GaAs or GaP compound semiconductor substrate 10 having an electrode 17 on one surface (lower surface), a light emitting layer 14, and a current diffusion layer 15 on this substrate.
Are formed by Evita cal growth and the electrode 1 is formed on the current spreading layer.
There is a semiconductor light emitting element substrate having a structure having 6 and a wiring electrode pattern 19. This compound semiconductor substrate is n-GaAs
Alternatively, n-GaP or p-GaP is used, and an n-InAlP or p-InAlP clad layer, an InGaAlP active layer, and a light emitting layer are formed on the light emitting layer in a multi-layered structure, and p-InAlP is formed on the light emitting layer. Alternatively, p-GaP or n-InGaAlP current diffusion layer 1
5 are stacked.

A solution of a block copolymer dissolved in a solvent was spin-coated on this light-emitting device substrate, and the substrate was rotated at a rotation speed of 2
After coating at 500 rpm, the solvent was vaporized by prebaking at 110 ° C. for 90 seconds. This block copolymer is made of polystyrene (PS) and polymethylmethacrylate (PMM).
A). The molecular weight of PS is 154800 and the molecular weight of PMMA is 392300. Mw / M
n is 1.08. Next, in a nitrogen atmosphere, at 210 ° C,
After annealing for 4 hours, PS of block copolymer 8
And PMMA were phase-separated (Fig. 2 (2)).

This phase-separated substrate with block copolymer was treated with CF _{4 of} 30 sccm and pressure of 1.33 Pa (10 mT).
oror), power = 100 W, by RIE,
The PS and PMMA of the phase-separated film were etched. At this time, due to the difference in etching rate between PS and PMMA, PMM
A is selectively etched, leaving a PS pattern (FIG. 2C). Using this PS pattern as a mask,
Cl ₂ = 100 sccm, 0.65 Pa (5 mTorr
r), when power = 300 W and RIE for about 30 sec,
A fine pattern was formed on the current spreading layer 15. Not only Cl ₂ but also BCl ₃ or Ar gas is used as a gas to be used for etching (FIG. 2 (4)). After that, the remaining PS was removed by an O ₂ asher. As a result, on the surface of the compound semiconductor substrate 4 other than the electrodes and the wiring pattern, the diameter (2 <R>) of the protrusion is about 50 to 70 nm, σ _R is 1.3, and the period is about 100 nm. Fine irregularities having (<H>) of about 60 to 150 nm and σ _H of 1.7 were formed (FIG. 2 (5)). When this was device-processed and compared with a light-emitting diode which was not surface-processed, a brightness improvement of 21% was observed on the average of ten.

(Example 2) Further, the same method as in Example 1
The phase-separated substrate with block copolymer prepared in
_Two30 sccm, pressure 13.3 Pa (100 mTorr
r), power = 100 W, RIE
Etch the separated PS and PMMA. O _TwoEtch
CF is CF_FourCan't scrape the board compared to
However, instead, the PMMA may be selectively etched.
You can Then, the same process as in Example 1 is performed.
It was As a result, a pattern similar to that of the example can be obtained.
Came. The diameter of the protrusion (2 <R>) is about 60 nm, σ_RBut
1.2, distribution with a period of about 100 nm, height (<H>)
Is about 110 nm, σ_HBut with a minute unevenness of 1.4
Came. This is an element processed, and light emission without surface processing
25% brighter on average when compared to 10 diodes
The improvement was seen.

(Example 3) The light emitting diode used in Example 1
PS: 315000 on the surface of the GaP light emitting layer
PMMA: Block copolymer with a molecular weight of 785,000
GaP substrate by spin coating method
After applying 3000 rpm to the
It was rebaked to vaporize the solvent and obtain a film thickness of 150 nm. Next
And anneal at 210 ° C for 4 hours in a nitrogen atmosphere.
Phase separation of PS and PMMA
A dot pattern of PS was formed. This phase separated professional
GaP substrate with a block copolymer_Two30 sccm,
Pressure 13.3Pa (100mTorr), Power = 10
By RIE under the condition of 0 W, phase-separated PS
And etch PMMA. O_TwoEtched
Can not cut the GaP substrate, but instead PM
The MA can be selectively etched. PS and P
Since the etching rate ratio of MMA is 1: 4, P
MMA is selectively etched, leaving PS pattern
The thickness was about 130 nm. this
Capacitively coupled plasma (I
CP: Inductive Coupled Plas
ma) with BCl_Three/ Cl _Two= 5 / 20scc
m, 0.266 Pa (2 mTorr), incident power / by
When ass power = 100 / 100W for 2 minutes, width 10
A pattern of 0 nm and a height of 300 nm was formed. That
After O_TwoThe remaining PS was removed by an asher. This conclusion
As a result, on the surface of the GaP light emitting layer, as shown in the photograph of FIG.
I got the pattern. Diameter of convex part (2 <R>)
Is 110 nm, σ_RIs 1.1 and the height (<H>) is 300
nm, σ_HWas 1.2. This is processed into an element, and the surface
Compared with the unprocessed light emitting diode,
A 10% average brightness improvement of 55% was observed.

Example 4 In addition, a substrate with a block copolymer prepared in the same manner as in Example 3 and phase-separated was
Cl ₃ / Cl ₂ = 5 / 20sccm, 0.266Pa
(2 mTorr), incident power / bias power = 100 /
By RIE at 100W, phase-separated PS and P
The MMA was etched. Since the etching rate ratio of PS and PMMA is 1: 4, PMMA is selectively etched and the PS pattern remains. Then, the same process as in Example 1 was performed. As a result, the diameter (2 <R>) of the protrusion is 1 on the surface of the compound semiconductor light emitting layer.
10 nm, σ _R is 1.1, and height (<H>) is 380 n
An unevenness of 1.6 was obtained for m and σ _H. In this process, PMMA was removed at once by RIE of BCl ₃ / Cl ₂ and irregularities were formed on the surface of the compound semiconductor light emitting layer. When this was device-processed and compared with a light-emitting diode which was not surface-processed, an improvement in luminance of 50% was observed on average for ten LEDs.

(Example 5) Further, a substrate with a block copolymer prepared in the same manner as in Example 1 and subjected to phase separation was prepared.
The main chain of PMMA was cut by irradiating the entire surface with an electron beam with an output of 2 MeV. Develop with a developing solution (methyl isobutyl ketone-isopropyl alcohol mixed solution), rinse, and
Only MMA was removed by dissolution, leaving a PS pattern. Then, etching was performed at 60 ° C. in phosphoric acid. As a result,
The diameter (2 <R>) of the convex portion is 80 nm, σ _R is 1.4, the average distance between vertices is 180 nm, and the height (<H>) is 120 n.
m and σ _H were 1.3. The improvement in brightness was about 10%. However, this material and this process can be used in a wet process, which shows that they are sufficiently effective.

Example 6 Polystyrene (PS) -polyisoprene (PI) was used as a block copolymer.
Was used. The molecular weight of PS was 450,000, the molecular weight of PI was 1230000, and Mw / Mn was 1.07. In the same manner as in Example 3, a phase-separated substrate having a block copolymer was prepared. Among the PS-PI block copolymers phase-separated with ozone, PI was selectively removed by ozone oxidation. Using this PS pattern as a mask, capacitively coupled plasma (ICP: Inductive Couple)
dPlasma), BCl ₃ / Cl ₂ = 5/2
A pattern was formed when 0 sccm, 0.266 Pa (2 mTorr) and incident power / bias power = 100/100 W were performed for 2 minutes. After that, the remaining PS was removed by an O ₂ asher. As a result, a pattern as shown in FIG. 4 could be obtained on the surface of the GaP light emitting layer. The diameter of the convex portion (2 <R>) is 140 nm, and σ _R is 1.
1, the height (<H>) was 500 nm, and σ _H was 1.3. When this was device-processed and compared with a light-emitting diode which was not surface-processed, an improvement in luminance of 75% was observed on average for ten LEDs.

In this method, since the PI monomer does not easily absorb water, a polymer having a high molecular weight is more likely to polymerize than PMMA during the polymerization. Therefore, it is easy to make the pattern large. In this method, the film must be as thick as the size of the pattern made by the block copolymer. Therefore, if the pattern is large, the height of the pattern transferred to the compound semiconductor can be increased. In addition, almost the same structure was obtained by using polybutadiene (PB) instead of PI.

(Embodiment 7) As shown in FIG.
A three-layer resist 31 (NISSAN CHEMICAL A
RCXHRiC-11) was applied to form a 500 nm thick film. This was baked in an oven at 300 ° C. for 1 minute. Then spin on glass (SOG) 3
2 (Tokyo Ohka OCD T-7) was spin-coated at 110 nm, and then on a hot plate at 200 ° C. for 60 seconds, and further 30 seconds.
It was baked at 0 ° C. for 60 seconds. Further, a solution prepared by dissolving the same block copolymer as in Example 3 in a solvent was applied to the substrate by spin coating at a rotation speed of 2500 rpm, and then 110 ° C., 9
The solvent was vaporized by pre-baking at 0 seconds. Next, in a nitrogen atmosphere, annealing was performed at 210 ° C. for 4 hours to perform phase separation of PS and PMMA of the block copolymer 8 (FIG. 3).
(2)).

This phase-separated substrate with block copolymer was treated with O _{2 at} 30 sccm and a pressure of 13.3 Pa (100 mT).
oror), power = 100 W, by RIE,
The PS and PMMA of the phase-separated film were etched (Fig. 3
(3)). At this time, the PMMA is selectively etched due to the difference in etching rate between PS and PMMA, and the PS pattern remains. Next, using this PS pattern as a mask, CF ₄ 30 sccm, pressure 1.33 Pa (10 mT
orr), and SOG was etched with power = 100 W. Further, O ₂ 30 sccm, pressure 1.33 Pa (10
When RIE was performed at mTorr) and power = 100 W, the lower resist film was etched, and a columnar pattern having a height of 500 nm could be obtained. Then BCl ₃ / N ₂ =
23: 7 sccm, 0.200 Pa (1.5 mTorr
r) and power = 500 W for etching (FIG. 3).
(4)). Finally, ashing was performed with oxygen to remove the polymer (FIG. 3 (5)). In addition, SOG is BC before that
With l ₃ / N ₂ etching, there was no problem as it was removed by scraping. As a result, etching of InGaAlP, which is difficult with the ordinary etching method, could be performed. The shape after etching has a convex portion with a diameter (2 <R>) of 1
10 nm, σ _R is 1.1, and height (<H>) is 320 n
m and σ _H were 1.4.

(Embodiment 8) In having the same structure as that of Embodiment 1
A spin-on-glass (SOG) 32 (Tokyo Oka OCD) is formed on a light-emitting element substrate having GaAlP formed on the light-emitting surface.
T-7) was spin-coated at 110 nm and baked on a hot plate at 200 ° C. for 60 seconds and further at 300 ° C. for 60 seconds. Further, a solution prepared by dissolving the same block copolymer as in Example 3 in a solvent was spin-coated on the substrate at a rotation speed of 2500.
After applying at rpm, the solvent was vaporized by prebaking at 110 ° C. for 90 seconds. Next, in a nitrogen atmosphere, 210 ° C., 4
Annealing was performed for a period of time to carry out phase separation of PS and PMMA of the block copolymer 8 (FIG. 3 (2)). The phase-separated substrate with block copolymer was treated with O ₂ 30 sccm,
Pressure 13.3Pa (100mTorr), Power = 10
By performing RIE at 0 W, the PS and P of the phase-separated film were
The MMA was etched (FIG. 3 (3)). At this time, PS
PMMA is selectively etched due to the difference in etching rate between PMMA and PMMA, and the PS pattern remains. Next, using this PS pattern as a mask, CF ₄ 30 sccm,
Pressure 1.33Pa (10mTorr), Power = 100
The SOG was etched with W. Next, BCl ₃ / N ₂ = 2
3: 7 sccm, 0.200 Pa (1.5 mTorr
r) and power = 500 W for etching (FIG. 3).
(4)). Finally, ashing was performed with oxygen to remove the polymer (FIG. 3 (5)). As a result, the shape after etching has a diameter of the convex portion (2 <R>) of 120 nm and a σ _R of 1.
1, a height (<H>) of 300 nm and a σ _H of 1.3, a conical pattern as shown in the photograph of FIG. 5 was obtained.
Such a shape is advantageous for providing a gradient of refractive index. When the luminous efficiency of this sample and the sample without the pattern were compared, it was confirmed that the luminance was improved by 80%.

(Example 9) A diblock copolymer composed of polystyrene (PS) and polymethylmethacrylate (PMMA) was synthesized by the living anion polymerization method. In living anionic polymerization, s-butyllithium was used as an initiator to polymerize PS in an inert gas atmosphere at -78 ° C, and then PMMA was polymerized. P
The molecular weight of S was 300,000 and the molecular weight of PMMA was 420,000. This molecular weight was measured by RI and UV by gel permeation chromatography (GPC) after extracting a small amount during the polymerization. Although most of the final products were PS-PMMA block copolymers, a few% homopolymer of PS was observed from the UV profile of GPC. This is because the active sites are deactivated when MMA is added after the PS has been polymerized in the process of synthesis, and therefore the PS homopolymer remains (Sample 1).

Sample 1 was dissolved in THF to prepare a 10% solution. To this, n-hexane was added with stirring until the weight ratio of THF and hexane was about 1: 1 so that a part of the polymer was precipitated. After stirring this for about 1 hour, the solid content was taken out by filtration. As a result, a PS-PMMA diblock polymer having a narrow molecular weight distribution could be obtained (Sample 2).

Similarly, PS-PMMA diblock copolymers having different molecular weights were synthesized by the living anion polymerization method. The molecular weight of PS was 315,000 and the molecular weight of PMMA was 785,000. Similar to sample 1, P
Since the homopolymer of S was contained in several%, it was purified by the same method to obtain a PS-PMMA diblock polymer having a narrow molecular weight distribution (Sample 3).

As a comparative sample, a PS-PMMA diblock copolymer was synthesized by the living radical polymerization method. In this sample, since PMMA is polymerized and then PS is polymerized, a homopolymer of PMMA is mixed as an impurity. Therefore, in order to remove PMMA, the homopolymer of PMMA was removed in the same manner as in Sample 2 by utilizing the difference in solubility due to the difference in molecular weight. The molecular weight of PS of this sample was 330000, the molecular weight of PMMA was 750000, and Mw / Mn was 2.

The PMMA to be added was prepared by two polymerization methods, an anionic polymerization method and a radical polymerization method.

As the substrate, gallium phosphide (GaP) and gallium arsenide (Ga) used as the substrate for the light emitting element are used.
As) was used. Sample 1 prepared as a sample
Each of the four block copolymers was dissolved in propylene glycol monomethyl ether acetate (PGMEA). The concentration of each polymer was 3% by weight. This solution was spin-coated on a substrate at a rotation speed of 2500 rpm, and then baked on a hot plate at 110 ° C. for 90 seconds to vaporize the solvent. Next, using an oven,
Annealing was performed for 0 hours in a nitrogen atmosphere to perform phase separation of PS and PMMA of the block copolymer in the film.

As a result, the sample 1 has 1 to 10
A phase separation pattern having a period of about μm was observed. This pattern was observed in the phase mode of an intermolecular force microscope (AFM). As a result, two different types of domains were observed in the phase separation pattern with a period of about 1 to 10 μm. 1
A pattern having a size of about 100 to 200 nm was observed in one domain. Nothing was observed in the other domain. Domains of about 1 to 10 μm were formed by these two and were mixed on the substrate. Further observation of this structure revealed the following. 1
Patterns of about 100 to 200 nm are PS and PM
The domain formed by the block copolymer of MA, in which nothing was observed, was a domain composed of homo PS. It is considered that this is because the PS-PMMA block copolymer and the PS homopolymer were macrophase-separated, and the PS-PMMA block copolymer was microphase-separated.

In the sample 2, a pattern having a size of about 100 to 200 nm was observed on the entire surface. The shape was a striped to spherical pattern. It is considered that this is because the PS homopolymer was removed by the purification and only the block copolymer was formed, so that macroscopic phase separation did not occur.

In the sample 3, a spherical pattern having a diameter of about 100 to 200 nm was observed on the entire surface (FIG. 6).

In the sample 4, spherical patterns having completely different diameters were observed on the entire surface (FIG. 7). Since the sample 4 has a wide molecular weight distribution, it is considered that there is considerable variation in the size of the generated microphase-separated structure. This is considered to be the cause of the generation of microphase-separated structures having different sizes. The experimental results obtained so far have been quite similar to the GaAs substrate. Further, the Si substrate tended to have a slightly larger shape, but almost the same results were obtained.

Example 10 Sample 2 had a low molecular weight P
The MMA homopolymer was mixed to form a spherical pattern. The PMMA used is as shown in Table 5 below.

[0089]

[Table 5]

Sample 2 and PMMA homopolymer were mixed in a weight ratio of 6: 4, each containing 3 wt% of P.
It was adjusted to be a GMEA solution. This solution was spin-coated on a gallium phosphide (GaP) substrate at a rotation speed of 2500.
After applying at rpm, the solvent was vaporized by prebaking at 110 ° C. for 90 seconds. Then, in a nitrogen atmosphere at 210 ° C for 4
Annealing was performed for 0 hours to perform phase separation of PS and PMMA of the block copolymer. This result was observed in the phase mode of AFM. As a result, PMMA1-4,
Regarding PMMA 7 to 9, a pattern in which PS islands having a diameter of about 110 nm were uniformly dispersed was obtained. On the other hand, PMMAs 5, 6, 11, and 12 are 1 to 10
Two different domains were observed in the pattern resulting from macroscopic phase separation with a period of about μm. In one domain, PS with a size of about 100 to 200 nm
-PMMA pattern was observed. Nothing was observed in the other domain, and the phase image revealed that it was the domain of PMMA. Figure 8 shows sample 2 and PMMA3
Is a phase image of. In addition, with respect to PMMA9, some macroscopic phase separation was observed. From the above results, if the molecular weight of the homopolymer to be added is too large, PS-PMMA
It was confirmed that the PMMA homopolymer did not dissolve in the block PMMA and phase separation occurred.

(Example 11) Using PMMA1 to 4 and PMMA7 to 9 each having the pattern formed in Example 10, the same composition as in Example 10 was mixed with Sample 2, and the same process was used. A thin film was formed on GaP. This solution was applied to a gallium arsenide (GaAs) substrate by spin coating at a rotation speed of 2500 rpm, and then 110 ° C., 90
The solvent was vaporized by pre-baking in seconds. Next, annealing is performed in a nitrogen atmosphere at 210 ° C. for 1, 2, 4, 8, 16, 40, and 100 hours to obtain PS and PM of the block copolymer.
Phase separation of MA was performed. This result was observed in the phase mode of AFM. The sample annealed for 40 hours was that of Example 10. PM with phase separation pattern
The diameter of MA was measured and the σ value from the average was calculated. The results are summarized in Table 6.

[0092]

[Table 6]

From the above results, the molecular weight is 10,000 to 2
It was found that the addition of PMMA during about 0000 was effective in enhancing the regularity of the phase separation pattern. With PMMA having a molecular weight of more than 30,000, the block copolymer and the homopolymer undergo macroscopic phase separation, and the desired ordered pattern cannot be obtained. Further, the effect of the molecular weight distribution of the added homopolymer was hardly visible.

Example 12 Using the PMMA3 and PMMA8 having the pattern formed in Example 10, the same composition as in Example 10 was mixed with Sample 2. In addition, Sample 3 in which a spherical pattern can be formed only by the block copolymer was also a 3 wt% PGMEA solution. This solution was spin-coated on a gallium arsenide (GaAs) substrate at a rotation speed of 2500 rpm, and then prebaked at 110 ° C. for 90 seconds to vaporize the solvent. These were annealed at 240 ° C. for 8 and 100 hours in a nitrogen atmosphere containing 3% hydrogen to perform phase separation of PS and PMMA of the block copolymer. Also, annealing was performed at 210 ° C. for 8,100 hours. This result was observed in the phase mode of AFM. The diameter of PMMA in the phase separation pattern was measured, and the σ value from the average was calculated. The results are summarized in Table 7.

[0095]

[Table 7]

From the above results, it was found that the samples obtained by adding the low molecular weight homopolymer to the block copolymer had higher regularity than the block copolymer alone, as long as the patterns of the same size could be formed. It was It was thought that a block copolymer with a single spherical domain would have a narrower molecular weight distribution and a more uniform pattern, but in reality, the addition of a low molecular weight homopolymer resulted in a more uniform structure. . It is considered that the patterns will be aligned if the annealing is continued for an infinite period of time, but if the annealing time is finite, the fluidity of the polymer will greatly increase. In other words, it is considered that the viscosity was reduced and the structure formation did not take time as much as the molecular weight decreased.

(Embodiment 13) An embodiment of the present invention will be described with reference to FIG. As shown in FIG. 2A, GaAs or GaP having an electrode 17 on one surface (lower surface).
The compound semiconductor substrate 10 of FIG.
There is a semiconductor light emitting element substrate having a structure in which the current diffusion layer 15 is formed by Ebita Cal growth and the electrode 16 and the wiring electrode pattern 19 are provided on the current diffusion layer. This compound semiconductor substrate is made of n-GaAs, n-GaP or p-Ga.
P is used, on which n-InAlP or p-In
An AlP clad layer, an InGaAlP active layer, and a light emitting layer are formed in a multi-layered structure having a hetero structure, and p-In is formed on the light emitting layer.
AlP or p-GaP or n-InGaAlP
Current diffusion layer 15 is laminated.

Sample 2 and PM were used as the phase-separated polymer.
The MA3 homopolymer was mixed at a weight ratio of 6: 4 and adjusted so as to be a 3 wt% PGMEA solution. Similarly, Sample 2 and PMMA8 were similarly prepared. Further, as a comparative example, Sample 3 was also adjusted to be a 3 wt% PGMEA solution.

After applying these solutions to the light emitting element substrate by spin coating at a rotation speed of 2500 rpm, 11
The solvent was vaporized by pre-baking at 0 ° C. for 90 seconds. Next, annealing was performed at 210 ° C. for 8 hours in a nitrogen atmosphere to perform phase separation of PS and PMMA of the block copolymer 8.

This phase-separated substrate with block copolymer was treated with CF ₄ = 30 sccm and pressure 1.33 Pa (10 m).
Torr) and power = 100 W were used to etch PS and PMMA of the phase-separated film by RIE.
At this time, due to the difference in etching rate between PS and PMMA, P
The MMA is selectively etched, leaving a pattern of PS. Cl ₂ = 10 using this PS pattern as a mask
0 sccm, 0.65 Pa (5 mTorr), power =
RIE at 300 W for about 30 sec, current diffusion layer 15
A fine pattern was formed. The gas used is Cl ₂
Not only that, etching can be performed by adding BCl ₃ or Ar gas. After that, the remaining PS was removed by an O ₂ asher. As a result, the diameter of the protrusion is 50 to 7 on the surface of the compound semiconductor substrate 4 other than the electrodes and the wiring pattern.
Fine irregularities having a distribution of about 0 nm, σR of 1.3 and a period of about 100 nm, a height of about 60 to 150 nm and a σH of 1.7 could be formed. When this was subjected to element processing and compared with a light emitting diode not subjected to surface processing, the average luminance of 10 pieces was compared. The results are shown in Table 8.

[0101]

[Table 8]

It is considered that these results indicate that the PS-PMMA pattern has a high degree of regularity to some extent, and thus the effect of the created graded index structure is high and the brightness is increased.

(Example 14) Next, as a phase-separated polymer, PS (polystyrene) -PI (polyisoprene) diblock copolymer (molecular weight (Mw) PS: 230,000, P
I: 400,000 Mw / Mn: 1.06) and a low molecular weight homopolymer (molecular weight Mw: 2000, Mw / Mn:
An example using a PI polymer is shown as 1.45). That is, a PS-PI diblock polymer was prepared by the living anion polymerization method in the same manner as in Example 9, and a low molecular weight homopolymer of PI prepared by a general radical polymerization method was added to the PS-PI diblock polymer to prepare PGEMEA. It was dissolved and made into a solution. In the same manner as in Example 13, a mixture of PS-PI diblock copolymer and PI homopolymer was formed into a thin film on a compound semiconductor substrate, and a microphase-separated structure was formed by thermal annealing, and then PI was removed by an ozone oxidation method. A PS etching mask was formed on the substrate. After that, a light emitting device was produced in the same manner as in Example 13.
As a result, the brightness was improved by about 40% as compared with the sample in which the light emitting surface was not processed.

Example 15 A diblock copolymer of polystyrene (PS) and polymethylmethacrylate (PMMA) was polymerized by the same method as the living anion polymerization method of Example 9. Further, unreacted components such as PS were removed in heated cyclohexane. The molecular weight of PS is 240,000,
PMMA is 730,000, Mw / Mn of all polymers is 1.08
Met. A sample obtained by adding PMMA of Mw 15000 and homopolymer of PS of molecular weight 9000 to this is G
A thin film was formed on the aAs substrate. The mixing ratio of PS-PMMA block copolymer, PMMA homopolymer, and PS homopolymer, and the P of the resulting microphase separation pattern
The diameter of S is as follows.

[0105]

[Table 9]

As a result, it can be seen that the spherical pattern of PS is increased by adding PS. In the pattern forming method used in the present invention, the film thickness needs to be set to the same extent as the diameter of the PS sphere. Therefore, the concentration of the polymer and the rotation number of spin coating were adjusted so that the film thickness was almost the same as the obtained diameter, and the polymer thin film was applied onto the GaP substrate on which the electrode was formed. This was annealed by the same method to generate a phase separation structure in the film. This phase-separated substrate with a block copolymer was O ₂ 30 sccm, pressure 1.33 Pa (10 mTorr), power = 100 W.
By RIE with P, the phase-separated polymer film P
The MMA was removed. Using the remaining PS pattern as a mask, Cl ₂ 100 sccm, 0.65 Pa (5 mTorr)
r), RIE with power = 300 W formed a fine pattern on the current diffusion layer. After that, the remaining PS was removed by an O ₂ asher. As a result, an uneven pattern was formed on the surface of the compound semiconductor substrate other than the electrodes and the wiring pattern. The shape of the concavo-convex pattern and the improvement in brightness as compared with the sample in which the concavo-convex pattern is not formed are shown in Table 10 below.

[0107]

[Table 10]

As described above, by adding a homopolymer to both the majority phase and the minority phase of the block copolymer, it is possible to increase the phase separation pattern of the block copolymer, and as a result, it becomes a mask for etching the compound semiconductor. Since the height of PS can be increased, the compound semiconductor can be etched deeply. As a result, it was found that unevenness having a high height can be obtained and the brightness is further improved. In addition, this method is effective when it is difficult to increase the molecular weight, and it is effective in reducing variation between lots.

(Example 16) First, a SiNx pattern was used as an etching mask to form a single crystal Al as follows.
_It is formed on ₂ O ₃ . Plasma C on single crystal Al ₂ O ₃
A 200 nm SiNx film is formed by the VD method, and PS:
315000, PMMA: A solution obtained by dissolving a block copolymer having a molecular weight of 785000 in PGMEA was applied to a single crystal Al ₂ O ₃ at 3000 rpm by a spin coating method, and then prebaked at 110 ° C. for 90 seconds to evaporate the solvent to 150 nm. The film thickness was obtained. Then 180 in a nitrogen atmosphere
Annealing was performed at 4 ° C. for 4 hours to perform phase separation between PS and PMMA to form a polystyrene dot pattern having a diameter of about 110 nm. This phase-separated single crystal Al ₂ O ₃ substrate with a block copolymer was O ₂ 30 sccm, pressure 13.3 Pa (100 mTorr), power = 100 W.
The phase-separated PS-P by RIE under the conditions
PMMA of MMA was selectively etched. As a result, the aggregated polystyrene having a size of about 0.1 μm remains at intervals of about 0.1 μm and becomes a mask for forming the SiNx pattern.

For this sample, Ar / CHF ₃ = 185
Etching was carried out for 6.5 minutes under the conditions of / 15 sccm, 40 mTorr and 100 W to form a SiNx pattern as an etching mask. Next, using the SiNx pattern as an etching mask, the single crystal Al ₂ O ₃ was added to the B
Cl ₃ / Ar = 80/20 sccm, 30 mTorr,
Etching was performed for 20 minutes under the condition of 100W. As a result, a concavo-convex shape having an average diameter of 110 nm and an average height of 200 nm could be formed on the surface of the single crystal Al ₂ O ₃ .
After that, n-Al (0.4) Ga is formed by a CVD process.
(0.6) N (contact layer), n-Al (0.35)
Ga (0.65) N (clad), n-Al (0.2
8) Ga (0.72) N / n-Al (0.24) Ga
(0.76) N (SL active layer), p-Al (0.4) G
a (0.6) N / p-Al (0.3) Ga (0.7) N
(SL clad layer) and p-GaN (contact layer) were sequentially stacked. After forming the electrode, it was cut into chips to obtain a light emitting device. FIG. 9 shows a block diagram of the device thus prepared. The emission intensity of ultraviolet light (λ = 300 nm) was compared with that of a light-emitting element that did not have the uneven structure of the present invention. As a result, the brightness of the one having the concavo-convex structure was improved by about 30% as compared with the one not subjected to the concavo-convex processing. Thus, it was confirmed that the structure obtained according to the present invention is effective even with UV light.

(Example 17) White light was emitted by placing a phosphor on the UV-LED in which unevenness was formed on the light emitting surface in Example 16. The phosphors used are as shown in Table 11 below.

[0112]

[Table 11]

A thin film of this phosphor was formed on the light emitting surface of the LED and sealed with an epoxy resin. Using the same phosphor, L
The brightness of white light was compared with that of an LED having no uneven structure on the ED surface. As a result, the brightness of the LED with unevenness was higher by about 25%. As a result, it was confirmed that the structure obtained by the present invention is also effective for a white LED using a phosphor.

[0114]

According to the present invention, the average diameter of the unevenness is smaller than the emission wavelength, the pitch of the unevenness has a distribution, and the height of the unevenness and the position of the bottom surface have a smooth slope of the refractive index. A nano concavo-convex structure characterized by having a width from the average value at a wavelength or less is formed on the surface. Thereby,
Achieve high luminous efficiency characteristics of light emitting devices and the like. In addition, a nanostructure-forming composition containing a block copolymer or a graft copolymer and forming a microphase-separated structure for self-assembling the microphase-separated structure is used, and at least one of the phase-separated structures formed on the surface is used. By selectively removing the phase and using the rest as an etching mask,
This is a manufacturing method that realizes high productivity without using an exposure apparatus, at low cost.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a light emitting device of the present invention.

FIG. 2 is a schematic view showing a manufacturing process of the light emitting device of the present invention.

FIG. 3 is a schematic view showing another example of the manufacturing process of the light emitting device of the present invention.

FIG. 4 is a photograph of observing the surface of a light emitting device obtained according to an example of the present invention.

FIG. 5 is a photograph of a surface of a light emitting device obtained according to another embodiment of the present invention.

FIG. 6 is a photograph showing a microphase-separated structure obtained in still another example of the present invention.

FIG. 7 is a photograph showing a microphase-separated structure obtained in still another example of the present invention.

FIG. 8 is a photograph showing a microphase-separated structure obtained in still another example of the present invention.

FIG. 9 is a sectional view of a light emitting device showing still another embodiment of the present invention.

FIG. 10 is a graph showing the molecular weight distribution of the resin composition used in the examples of the present invention.

[Explanation of symbols]

11 ... Substrate 12 ... Active layer 13 ... Clad layer 14 ... Heterostructure part 15 ... Current spreading layer 16 ... Upper electrode 17 ... Lower electrode 18 ... Micro unevenness 21 ... Microstructure-forming resin composition thin film 22 ... Pattern 31 ... First resist film 32 ... Second resist film

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hitoshi Sugiyama             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Ceremony Company Toshiba Microelectronics Sen             Inside (72) Inventor Kenichi Ohashi             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Ceremony Company Toshiba Microelectronics Sen             Inside (72) Inventor Junichi Tonoya             33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa             Inside the Toshiba Production Technology Center (72) Inventor Hiroyuki Suzuki             33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa             Inside the Toshiba Production Technology Center F-term (reference) 5F004 BB13 DA01 DA04 DA11 DA23                       DA26 DB23 EA28 EA37 EA38                       EA40                 5F041 AA03 CA04 CA12 CA34 CA35                       CA37 CA74 CA77 CB36

Claims (12)

[Claims] 1. A light emitting side of a semiconductor layer constituting a light emitting device.
Inorganic light formed on the surface of the outer layer or on the outermost layer on the light emitting side
It is an element in which the surface of the transparent layer is provided with fine irregularities.
The surface has a surface property satisfying the following two conditions.
Light emitting element. (1) Average turning radius <R> (where
<R> = ΣR^Twon_R/ ΣRn _R, N_RIs an arbitrary turning radius
Is 1/20 or more and 1/2 of the light wavelength.
Below, and the degree of dispersion σ of the radius of gyration_R(However, σ
_R= <R> / (ΣRn _R/ Σn_R), N_RIs any rotation
The number of convex portions having a radius) is 1.05 or more and 2 or less.
To do. (2) Average height of convex and concave portions <H> (where <H> =
ΣH^Twon_H/ ΣHn_H, N_RIs a convex part with an arbitrary height
The number is 1/10 or more and 1 or less of the light wavelength, and
Dispersion σ_H(However, σ_H= <H> / (ΣHn_H/ Σn
_H), N_RIs the number of convex portions having an arbitrary height) is 1.0
Must be 5 or more and 2 or less. 2. A thin film is formed on the surface of a light emitting device using a resin composition containing a block copolymer or a graft copolymer and forming a microphase-separated structure in a self-assembled manner.
Manufacturing of a light emitting device, characterized in that at least one phase of the microphase-separated structure of the thin film formed on the surface is selectively removed and the surface of the light emitting device is etched using the remaining phase as an etching mask. Method. 3. A thin film is formed on the surface of a substrate by using a resin composition containing a block copolymer or a graft copolymer and self-organizing a microphase-separated structure, and the microphase of the thin film formed on the surface. A light emitting device material is formed on a substrate having a structure formed by selectively removing at least one phase of the separation structure and etching the surface of the substrate using the remaining phase as an etching mask. And a method for manufacturing a light emitting device. 4. The method for producing a light emitting device according to claim 2, wherein the block copolymer or graft copolymer has a number average molecular weight of 100,000 or more and 10,000,000 or less. 5. The method for producing a light emitting device according to claim 4, wherein the ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight of the block copolymer is 1.2 or less. 6. The method for producing a light emitting device according to claim 4, wherein the block copolymer or the graft copolymer is produced by living anion polymerization. For 7. At least two polymer chains of the plurality of polymer chains constituting the block copolymer or graft copolymer, the ratio of N / (N C _{-N O)} of the monomer units constituting each polymer chain 1 7 or more (where N is the total number of atoms in the monomer unit, N _C is the number of carbon atoms in the monomer unit, and N 2 _O is the number of oxygen atoms in the monomer unit). A method for manufacturing a light-emitting device according to any one of claims 8. The method for manufacturing a light emitting device according to claim 6, wherein the block copolymer or the graft copolymer is a copolymer of styrene and methyl methacrylate. 9. The method for producing a light-emitting element according to claim 2, wherein the resin composition is the block copolymer or the graft copolymer to which a low molecular weight homopolymer is added. 10. The light emission according to claim 2, wherein the low molecular weight homopolymer is one homopolymer of a plurality of monomers constituting the block copolymer or the graft copolymer. Device manufacturing method. 11. The molecular weight of the low molecular weight homopolymer (M
11. The method for manufacturing a light emitting device according to claim 10, wherein w) is 1,000 or more and 30,000 or less. 12. The method for producing a light emitting device according to claim 9, wherein the low molecular weight homopolymer is polymethylmethacrylate and / or polystyrene.