JP2022065560A - Substrate processing method and substrate processing device - Google Patents

Abstract

To provide a substrate processing method and a substrate processing device that can adjust the composition of a film to be formed.SOLUTION: A substrate processing method includes the steps of: forming a film on a substrate by repeating, at least once or more, a cycle including the step of supplying a material gas containing silicon, carbon, and halogen to the substrate and the step of supplying a first reaction gas to the substrate; and exposing the substrate to plasma of a hydrogen-containing gas so as to modify the film formed on the substrate.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a substrate processing method and a substrate processing apparatus.

With the miniaturization of semiconductor devices, a method for forming an insulating film having a low dielectric constant and high wet etching resistance is known for use as a spacer for gates and contacts.

Patent Document 1 describes a step of forming a predetermined element-containing layer on the substrate by supplying a predetermined element-containing gas under the condition that a CVD reaction occurs in the processing container containing the substrate, and a step of forming the predetermined element-containing layer in the processing container. A step of forming a carbon-containing layer on the predetermined element-containing layer to form a layer containing the predetermined element and carbon by supplying a carbon-containing gas, and supplying a nitrogen-containing gas into the treatment container. A step of forming a carbonitride layer by nitriding a layer containing the predetermined element and carbon, and a step of forming a carbonitride layer having a predetermined thickness by performing this set a predetermined number of times with the set as one set, and the above-mentioned treatment. The substrate is formed by performing this cycle a predetermined number of times, with the step of forming an acid carbon dioxide layer by oxidizing the carbon dioxide layer having a predetermined thickness by supplying an oxygen-containing gas into the container as one cycle. A method for manufacturing a semiconductor device, which comprises a step of forming an acid carbon nitride film having a predetermined film thickness, is disclosed above.

Japanese Patent No. 2011-238894

In one aspect, the present disclosure provides a substrate processing method and a substrate processing apparatus capable of adjusting the composition of the produced film.

In order to solve the above problems, according to one aspect, a step of supplying a raw material gas containing silicon, carbon and halogen to the substrate and a step of supplying the first reaction gas to the substrate are included. Substrate treatment comprising a step of forming a film on the substrate by repeating a cycle at least once, and a step of exposing the substrate to plasma of a hydrogen-containing gas to modify the film formed on the substrate. The method is provided.

According to one aspect, it is possible to provide a substrate processing method and a substrate processing apparatus capable of adjusting the composition of the produced film.

An example of a schematic diagram showing a configuration example of a substrate processing apparatus. The flowchart which shows an example of the operation in the substrate processing apparatus which concerns on this Example. The flowchart which shows the other example of the operation in the substrate processing apparatus which concerns on this Example. An example of a graph showing the relationship between the frequency of the reforming process and the composition of the insulating film. An example of a graph showing the frequency of the reforming step and the relationship between the RF power and the composition of the insulating film. An example of a graph showing the relationship between the frequency of the reforming process and the relative permittivity and film density of the insulating film. An example of a graph showing the frequency of the reforming step and the relationship between the RF power and the relative permittivity and the film density of the insulating film.

Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals and duplicate explanations may be omitted.

[Board processing equipment]
The substrate processing apparatus 100 according to this embodiment will be described with reference to FIG. FIG. 1 is an example of a schematic diagram showing a configuration example of the substrate processing apparatus 100. The substrate processing apparatus 100 is an apparatus for forming an insulating film (for example, a SiCN film or a SiOCN film) on a wafer (substrate) W by an ALD (Atomic Layer Deposition) method in a processing container in a reduced pressure state.

As shown in FIG. 1, the substrate processing apparatus 100 includes a processing container 1, a mounting table 2, a shower head 3, an exhaust unit 4, a gas supply mechanism 5, an RF power supply unit 8, and a control unit 9. And have.

The processing container 1 is made of a metal such as aluminum and has a substantially cylindrical shape. The processing container 1 accommodates the wafer W. A carry-in outlet 11 for carrying in or out the wafer W is formed on the side wall of the processing container 1, and the carry-in outlet 11 is opened and closed by the gate valve 12. An annular exhaust duct 13 having a rectangular cross section is provided on the main body of the processing container 1. A slit 13a is formed in the exhaust duct 13 along the inner peripheral surface. An exhaust port 13b is formed on the outer wall of the exhaust duct 13. A top wall 14 is provided on the upper surface of the exhaust duct 13 so as to close the upper opening of the processing container 1 via the insulator member 16. The exhaust duct 13 and the insulator member 16 are hermetically sealed with a seal ring 15. When the mounting table 2 (and the cover member 22) rises to the processing position described later, the partition member 17 partitions the inside of the processing container 1 up and down.

The mounting table 2 horizontally supports the wafer W in the processing container 1. The mounting table 2 is formed in a disk shape having a size corresponding to the wafer W, and is supported by the support member 23. The mounting table 2 is made of a ceramic material such as AlN or a metal material such as aluminum or nickel alloy, and a heater 21 for heating the wafer W is embedded therein. The heater 21 is supplied with power from a heater power supply (not shown) to generate heat. Then, the wafer W is controlled to a predetermined temperature by controlling the output of the heater 21 by the temperature signal of the thermocouple (not shown) provided near the upper surface of the mounting table 2. The mounting table 2 is provided with a cover member 22 formed of ceramics such as alumina so as to cover the outer peripheral region of the upper surface and the side surface.

A support member 23 for supporting the mounting table 2 is provided on the bottom surface of the mounting table 2. The support member 23 extends from the center of the bottom surface of the mounting table 2 to the lower side of the processing container 1 through a hole formed in the bottom wall of the processing container 1, and its lower end is connected to the elevating mechanism 24. The elevating mechanism 24 causes the mounting table 2 to move up and down via the support member 23 between the processing position shown in FIG. 1 and the transfer position below which the wafer W can be transferred, which is indicated by the alternate long and short dash line. A flange portion 25 is attached below the processing container 1 of the support member 23, and the atmosphere inside the processing container 1 is partitioned from the outside air between the bottom surface of the processing container 1 and the flange portion 25, and the mounting table 2 is used. A bellows 26 that expands and contracts as the vehicle moves up and down is provided.

In the vicinity of the bottom surface of the processing container 1, three wafer support pins 27 (only two are shown) are provided so as to project upward from the elevating plate 27a. The wafer support pin 27 is moved up and down via the raising and lowering plate 27a by the raising and lowering mechanism 28 provided below the processing container 1. The wafer support pin 27 is inserted into a through hole 2a provided in the mounting table 2 at the transport position so that the wafer support pin 27 can be recessed with respect to the upper surface of the mounting table 2. By raising and lowering the wafer support pin 27, the wafer W is transferred between the transfer mechanism (not shown) and the mounting table 2.

The shower head 3 supplies the processing gas into the processing container 1 in the form of a shower. The shower head 3 is made of metal, is provided so as to face the mounting table 2, and has substantially the same diameter as the mounting table 2. The shower head 3 has a main body portion 31 fixed to the top wall 14 of the processing container 1 and a shower plate 32 connected under the main body portion 31. A gas diffusion space 33 is formed between the main body 31 and the shower plate 32, and the gas introduction hole 36 is formed in the gas diffusion space 33 so as to penetrate the top wall 14 of the processing container 1 and the center of the main body 31. Is provided. An annular protrusion 34 projecting downward is formed on the peripheral edge of the shower plate 32. A gas discharge hole 35 is formed on the flat surface inside the annular protrusion 34. When the mounting table 2 is present at the processing position, a processing space 38 is formed between the mounting table 2 and the shower plate 32, and the upper surface of the cover member 22 and the annular protrusion 34 are close to each other to form an annular gap 39. Will be done.

The exhaust unit 4 exhausts the inside of the processing container 1. The exhaust unit 4 has an exhaust pipe 41 connected to the exhaust port 13b, and an exhaust mechanism 42 having a vacuum pump, a pressure control valve, and the like connected to the exhaust pipe 41. At the time of processing, the gas in the processing container 1 reaches the exhaust duct 13 through the slit 13a, and is exhausted from the exhaust duct 13 through the exhaust pipe 41 by the exhaust mechanism 42.

The gas supply mechanism 5 supplies the processing gas into the processing container 1. The gas supply mechanism 5 has a precursor gas supply source 51a, a first reaction gas supply source 52a, a second reaction gas supply source 53a, and a hydrogen gas supply source 54a.

The precursor gas supply source 51a supplies the precursor gas (raw material gas) into the processing container 1 via the gas supply line 51b. As the precursor gas, a silicon precursor having at least a halogen group is used. Further, as the precursor gas, a precursor containing silicon, carbon, and halogen is used. Further, as the precursor gas, a silicon precursor having at least a halogen group and an alkyl group is used. The halogen of the silicon precursor may contain, for example, at least one of Cl, F, Br and I. For example, in the example shown in FIG. 1, 1,1,3,3-tetrachloro-1,3-disilacyclobutane (C ₂ H ₄ Cl ₄ Si ₂ ) represented by the following structural formula is used.

A flow rate controller 51c and a valve 51d are interposed in the gas supply line 51b from the upstream side. The downstream side of the valve 51d of the gas supply line 51b is connected to the gas introduction hole 36 via the gas supply line 57. The precursor gas supplied from the precursor gas supply source 51a is supplied into the processing container 1. The supply and stop of the precursor gas from the precursor gas supply source 51a to the processing container 1 is performed by opening and closing the valve 51d.

The first reaction gas supply source 52a supplies the first reaction gas into the processing container 1 via the gas supply line 52b. Nitriding gas (nitrogen-containing gas) is used as the first reaction gas. As the nitriding gas, for example, ammonia NH ₃ , hydrazine N ₂ H ₄ , monomethylhydrazine CH ₃ (NH) NH ₂ and the like can be used. In the example shown in FIG. 1, NH ₃ is used as the first reaction gas (nitriding gas).

A flow rate controller 52c and a valve 52d are interposed in the gas supply line 52b from the upstream side. The downstream side of the valve 52d of the gas supply line 52b is connected to the gas introduction hole 36 via the gas supply line 57. The first reaction gas supplied from the first reaction gas supply source 52a is supplied into the processing container 1. The supply and stop of the first reaction gas from the first reaction gas supply source 52a to the processing container 1 is performed by opening and closing the valve 52d.

The second reaction gas supply source 53a supplies the second reaction gas into the processing container 1 via the gas supply line 53b. Oxidation gas (oxygen-containing gas) is used as the second reaction gas. As the oxidizing gas, for example, _H2O , _O2 , _H2O2 , IPA ₍ isopropyl alcohol) and the like can be used. In the example shown in FIG. 1, _H2O is used as the second reaction gas (oxidizing gas).

A flow rate controller 53c and a valve 53d are interposed in the gas supply line 53b from the upstream side. The downstream side of the valve 53d of the gas supply line 53b is connected to the gas introduction hole 36 via the gas supply line 57. The second reaction gas supplied from the second reaction gas supply source 53a is supplied into the processing container 1. The supply and stop of the second reaction gas from the second reaction gas supply source 53a to the processing container 1 is performed by opening and closing the valve 53d.

The hydrogen gas supply source 54a supplies the hydrogen-containing gas into the processing container 1 via the gas supply line 54b. In the example shown in FIG. 1, H ₂ is used as the hydrogen-containing gas.

A flow rate controller 54c and a valve 54d are interposed in the gas supply line 54b from the upstream side. The downstream side of the valve 54d of the gas supply line 54b is connected to the gas introduction hole 36 via the gas supply line 57. The hydrogen-containing gas supplied from the hydrogen gas supply source 54a is supplied into the processing container 1. The supply and stop of the hydrogen-containing gas from the hydrogen gas supply source 54a to the processing container 1 is performed by opening and closing the valve 54d.

The carrier gas / purge gas supply sources 55a and 56a supply the carrier gas / purge gas into the processing container 1 via the gas supply lines 55b and 56b. As the carrier gas / purge gas, for example, He, Ne, Ar, Kr, Xe, N ₂ and the like can be used. In the example shown in FIG. 1, Ar is used as the carrier gas / purge gas.

Flow controllers 55c and 56c and valves 55d and 56d are interposed in the gas supply lines 55b and 56b from the upstream side. The downstream sides of the valves 55d and 56d of the gas supply lines 55b and 56b are connected to the gas introduction hole 36 via the gas supply line 57. The carrier gas / purge gas supplied from the carrier gas / purge gas supply sources 55a and 56a is supplied into the processing container 1. The supply and stop of the carrier gas / purge gas from the carrier gas / purge gas supply sources 55a and 56a to the processing container 1 are performed by opening and closing the valves 55d and 56d.

Further, the substrate processing device 100 is a capacitively coupled plasma device, in which the mounting table 2 serves as a lower electrode and the shower head 3 serves as an upper electrode. The mounting table 2 serving as the lower electrode is grounded via a capacitor (not shown).

High frequency power (hereinafter, also referred to as “RF power”) is applied to the shower head 3 serving as the upper electrode by the RF power supply unit 8. The RF power supply unit 8 includes a power supply line 81, a matching unit 82, and a high frequency power supply 83. The high frequency power supply 83 is a power supply that generates high frequency power. High frequency power has a frequency suitable for plasma generation. The frequency of the high frequency power is, for example, a frequency in the range of 450 KHz to 100 MHz. The high frequency power supply 83 is connected to the main body 31 of the shower head 3 via the matching unit 82 and the feeding line 81. The matching device 82 has a circuit for matching the output reactance of the high frequency power supply 83 and the reactance of the load (upper electrode). Although the RF power supply unit 8 has been described as applying high frequency power to the shower head 3 serving as the upper electrode, the present invention is not limited to this. High frequency power may be applied to the mounting table 2 serving as the lower electrode.

The control unit 9 is, for example, a computer, and includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an auxiliary storage device, and the like. The CPU operates based on a program stored in the ROM or the auxiliary storage device, and controls the operation of the board processing device 100. The control unit 9 may be provided inside the substrate processing device 100 or may be provided outside. When the control unit 9 is provided outside the board processing device 100, the control unit 9 can control the board processing device 100 by a communication means such as wired or wireless.

[Film film processing using a substrate processing device]
An example of the operation of the substrate processing apparatus 100 will be described with reference to FIG. FIG. 2 is a flowchart showing an example of the operation in the substrate processing apparatus 100 according to the present embodiment. Here, the substrate processing apparatus 100 forms a SiOCN film on the wafer W.

In step S101, the wafer W is prepared. First, the wafer W is carried into the processing container 1 of the substrate processing apparatus 100 shown in FIG. Specifically, the gate valve 12 is opened with the mounting table 2 lowered to the transport position. Subsequently, the wafer W is carried into the processing container 1 through the carry-in outlet 11 by a transport arm (not shown), and the mounting table 2 is heated to a predetermined temperature (for example, 200 ° C. to 500 ° C.) by the heater 21. Place on top. Subsequently, the mounting table 2 is raised to the processing position, and the inside of the processing container 1 is depressurized to a predetermined degree of vacuum by the exhaust mechanism 42. After depressurization, the control unit 9 opens the valves 55d and 56d. Ar gas is supplied from the carrier gas / purge gas supply sources 55a and 56a. As a result, the inside of the processing container 1 is stabilized at a predetermined pressure.

Next, the control unit 9 performs a film forming step (S102 to S106) for forming a SiOCN film on the wafer W.

In step S102, the precursor gas is supplied to the wafer W while maintaining the supply of Ar gas. The control unit 9 opens the valve 51d. The precursor gas is supplied into the processing space 38 from the precursor gas supply source 51a. As a result, the precursor is adsorbed on the surface of the wafer W, and the adsorption layer of the precursor is formed on the surface of the wafer W. After a lapse of a predetermined time, the control unit 9 closes the valve 51d. As a result, the excess precursor gas or the like in the processing space 38 is purged with Ar gas. When the predetermined purge time has elapsed, the process of the control unit 9 proceeds to step S103.

In step S103, the first reaction gas (nitriding gas) is supplied to the wafer W while maintaining the supply of Ar gas. The control unit 9 opens the valve 52d. The first reaction gas (nitriding gas) is supplied into the processing space 38 from the first reaction gas supply source 52a. As a result, the adsorbed adsorption layer on the surface of the wafer W is nitrided. That is, the halogen group (Cl) of the adsorbed precursor on the surface of the wafer W is replaced with the amino group (NH ₂ ) of the nitride gas (NH ₃ ). After a lapse of a predetermined time, the control unit 9 closes the valve 52d. As a result, the surplus first reaction gas or the like in the processing space 38 is purged with Ar gas. When the predetermined purge time has elapsed, the process of the control unit 9 proceeds to step S104.

In step S104, the control unit 9 determines whether or not the number of cycles has reached a predetermined number of repetitions X, with the process shown in steps S102 to S103 as one cycle. When the number of repetitions X has not been reached (S104 / No), the process of the control unit 9 returns to step S102, and the cycle of step S102 to step S103 is repeated. When the number of repetitions X is reached (S104 · Yes), the counter in step S104 is reset, and the processing of the control unit 9 proceeds to step S105.

In step S105, the second reaction gas (oxidizing gas) is supplied to the wafer W while maintaining the supply of Ar gas. The control unit 9 opens the valve 53d. The second reaction gas (oxidizing gas) is supplied into the processing space 38 from the second reaction gas supply source 53a. As a result, the adsorption layer on the surface of the wafer W is oxidized. That is, the halogen group (Cl) of the adsorbed precursor on the surface of the wafer W is replaced with the hydroxy group (OH) of the oxidizing gas ( _H2O ). When the predetermined time elapses, the control unit 9 closes the valve 53d. As a result, the excess second reaction gas or the like in the processing space 38 is purged with Ar gas. When the predetermined purge time has elapsed, the process of the control unit 9 proceeds to step S106.

In step S106, the control unit 9 determines whether or not the number of cycles has reached the predetermined number of repetitions Y, with the process shown in steps S102 to S105 as one cycle. When the number of repetitions Y has not been reached (S106, No), the process of the control unit 9 returns to step S102, and the cycle of step S102 to step S105 is repeated. When the number of repetitions Y is reached (S106 · Yes), the counter in step S106 is reset, and the processing of the control unit 9 proceeds to step S107.

In step S107, the insulating film (SiOCN film) formed on the wafer W is modified with hydrogen plasma while maintaining the supply of Ar gas. The control unit 9 opens the valve 54d. Hydrogen gas is supplied into the processing space 38 from the hydrogen gas supply source 54a. Further, the control unit 9 applies high frequency power (RF) to the upper electrode by the high frequency power supply 83 to generate plasma in the processing space 38. The power (RF power) applied from the high frequency power supply 83 to the upper electrode is, for example, 10 W to 2000 W, and the application time (RF time) is, for example, 0.1 sec to 10.0 sec. By exposing the wafer W to plasma of a hydrogen-containing gas, the SiOCN film formed on the wafer W is modified. After a lapse of a predetermined time, the control unit 9 stops applying RF to the upper electrode and closes the valve 54d. As a result, the excess hydrogen gas or the like in the processing space 38 is purged with Ar gas. When the predetermined purge time elapses, the process of the control unit 9 proceeds to step S108.

In the reforming step, the insulating film (SiOCN film) formed on the surface of the wafer W is exposed to hydrogen plasma to break weak bonds such as CH ₃ and NH ₂ in the insulating film, and CH _x and NH. The unbonded hands formed by the reaction of H of _x with hydrogen radicals and removal as H ₂ form new bonds such as Si—O-Si, Si—C—Si, and Si—N—Si. As a result, the film quality can be made stronger. In other words, the wet etching resistance of the insulating film (SiOCN film) can be improved.

In step S108, the control unit 9 determines whether or not the number of cycles has reached a predetermined number of repetitions Z, with the process shown in steps S102 to S107 as one cycle. When the number of repetitions Z has not been reached (S108 / No), the process of the control unit 9 returns to step S102, and the cycle of step S102 to step S107 is repeated. When the number of repetitions Z is reached (S108 · Yes), the counter in step S108 is reset to end the processing of the control unit 9 shown in FIG.

According to the insulating film forming method shown in FIG. 2, the halogen group (Cl) of the silicon precursor (C ₂ H ₄ Cl ₄ Si ₂ ) is replaced with the amino group (NH ₂ ) of the nitride gas (NH ₃ ). As a result, film formation progresses. As a result, C of the alkyl group of the silicon precursor is incorporated into the insulating film. In addition, nitriding does not require plasma due to the nitrogen-containing gas. Therefore, it is possible to suppress the desorption of C by plasma during nitriding. Therefore, an insulating film (SiOCN film) containing a high concentration of C can be formed. Further, since the film is formed by the ALD method, the film can be formed with good coverage.

Another example of the operation of the substrate processing apparatus 100 will be described with reference to FIG. FIG. 3 is a flowchart showing another example of the operation in the substrate processing apparatus 100 according to the present embodiment. Here, the substrate processing apparatus 100 forms a SiCN film on the wafer W.

In step S201, the wafer W is prepared. First, the wafer W is carried into the processing container 1 of the substrate processing apparatus 100 shown in FIG. Specifically, the gate valve 12 is opened with the mounting table 2 lowered to the transport position. Subsequently, the wafer W is carried into the processing container 1 through the carry-in outlet 11 by a transport arm (not shown), and the mounting table 2 is heated to a predetermined temperature (for example, 200 ° C. to 500 ° C.) by the heater 21. Place on top. Subsequently, the mounting table 2 is raised to the processing position, and the inside of the processing container 1 is depressurized to a predetermined degree of vacuum by the exhaust mechanism 42. After depressurization, the control unit 9 opens the valves 55d and 56d. Ar gas is supplied from the carrier gas / purge gas supply sources 55a and 56a. As a result, the inside of the processing container 1 is stabilized at a predetermined pressure.

Next, the control unit 9 performs a film forming step (S202 to S204) for forming a SiCN film on the wafer W.

In step S202, the precursor gas is supplied to the wafer W while maintaining the supply of Ar gas. The control unit 9 opens the valve 51d. The precursor gas is supplied into the processing space 38 from the precursor gas supply source 51a. As a result, the precursor is adsorbed on the surface of the wafer W, and the adsorption layer of the precursor is formed on the surface of the wafer W. After a lapse of a predetermined time, the control unit 9 closes the valve 51d. As a result, the excess precursor gas or the like in the processing space 38 is purged with Ar gas. When the predetermined purge time has elapsed, the process of the control unit 9 proceeds to step S203.

In step S203, the first reaction gas (nitriding gas) is supplied to the wafer W while maintaining the supply of Ar gas. The control unit 9 opens the valve 52d. The first reaction gas (nitriding gas) is supplied into the processing space 38 from the first reaction gas supply source 52a. As a result, the adsorbed adsorption layer on the surface of the wafer W is nitrided. That is, the halogen group (Cl) of the adsorbed precursor on the surface of the wafer W is replaced with the amino group (NH ₂ ) of the nitride gas (NH ₃ ). After a lapse of a predetermined time, the control unit 9 closes the valve 52d. As a result, the surplus first reaction gas or the like in the processing space 38 is purged with Ar gas. When the predetermined purge time has elapsed, the process of the control unit 9 proceeds to step S204.

In step S204, the control unit 9 determines whether or not the number of cycles has reached a predetermined number of repetitions X, with the process shown in steps S202 to S203 as one cycle. When the number of repetitions X has not been reached (S204 / No), the process of the control unit 9 returns to step S202, and the cycle of step S202 to step S203 is repeated. When the number of repetitions X is reached (S204 · Yes), the counter in step S204 is reset, and the processing of the control unit 9 proceeds to step S205.

In step S205, the SiCN film formed on the wafer W is modified with hydrogen plasma while maintaining the supply of Ar gas. The control unit 9 opens the valve 54d. Hydrogen gas is supplied into the processing space 38 from the hydrogen gas supply source 54a. Further, the control unit 9 applies high frequency power (RF) to the upper electrode by the high frequency power supply 83 to generate plasma in the processing space 38. The power (RF power) applied from the high frequency power supply 83 to the upper electrode is, for example, 10 W to 2000 W, and the application time (RF time) is, for example, 0.1 sec to 10.0 sec. By exposing the wafer W to plasma of a hydrogen-containing gas, the SiCN film formed on the wafer W is modified. After a lapse of a predetermined time, the control unit 9 stops applying RF to the upper electrode and closes the valve 54d. As a result, the excess hydrogen gas or the like in the processing space 38 is purged with Ar gas. When the predetermined purge time has elapsed, the process of the control unit 9 proceeds to step S206.

In the reforming step, the insulating film (SiCN film) formed on the surface of the wafer W is exposed to hydrogen plasma to break weak bonds such as CH ₃ and NH ₂ in the insulating film, and CH _x and NH. The unbonded hands formed by the reaction of H of _x with hydrogen radicals and removal as H ₂ form new bonds such as Si—C—Si and Si—N—Si. As a result, the film quality can be made stronger. In other words, the wet etching resistance of the insulating film (SiCN film) can be improved.

In step S206, the control unit 9 determines whether or not the number of cycles has reached a predetermined number of repetitions Z, with the process shown in steps S202 to S205 as one cycle. When the number of repetitions Z has not been reached (S206, No), the process of the control unit 9 returns to step S202, and the cycle of step S202 to step S205 is repeated. When the number of repetitions Z is reached (S206 · Yes), the counter in step S206 is reset to end the processing of the control unit 9 shown in FIG.

According to the insulating film forming method shown in FIG. 3, the halogen group (Cl) of the silicon precursor (C ₂ H ₄ Cl ₄ Si ₂ ) is replaced with the amino group (NH ₂ ) of the nitride gas (NH ₃ ). As a result, film formation progresses. As a result, C of the alkyl group of the silicon precursor is incorporated into the insulating film. In addition, nitriding does not require plasma due to the nitrogen-containing gas. Therefore, it is possible to suppress the desorption of C by plasma during nitriding. Therefore, an insulating film (SiCN film) containing a high concentration of C can be formed. Further, since the film is formed by the ALD method, the film can be formed with good coverage.

Next, the relationship between the frequency of the reforming step and the composition of the insulating film will be described with reference to FIG. FIG. 4 is an example of a graph showing the relationship between the frequency of the reforming step and the composition of the insulating film. Here, C ₂ H ₄ Cl ₄ Si ₂ as the precursor gas, NH ₃ as the nitride gas, H ₂ O as the oxidation gas, H ₂ as the hydrogen gas, and Ar as the carrier gas / purge gas, and the temperature is 450 according to the flow shown in FIG. The film composition at the time of forming an insulating film (SiOCN film) until a desired film thickness is obtained at ° C. is shown.

In the flow shown in FIG. 2, for the number of repetitions X, the step of supplying the precursor (S102) and the step of supplying the nitriding gas (S103) are set as one cycle, and the step of supplying the oxidation gas is performed in each X cycle (S105). It is shown that. That is, X indicates the frequency of the step (S105) of supplying the oxidizing gas. Further, the product XY of the number of repetitions X and the number of repetitions Y is a reforming step (S107) for each XY cycle, with the step of supplying the precursor (S102) and the step of supplying the nitride gas (S103) as one cycle. ) Is performed. That is, XY indicates the frequency of the reforming step (S107).

In FIG. 4, the frequency (XY) of the reforming step (S107) and the composition of the insulating film are shown with X = 1. “Non-plasma” shows the composition of the insulating film when not modified by hydrogen plasma. "Low P-H2" shows the composition of the insulating film when the modification with hydrogen plasma is performed once every 64 cycles. "Mid P-H2" shows the composition of the insulating film when the modification with hydrogen plasma is performed once every 16 cycles. "High P-H2" shows the composition of the insulating film when the modification with hydrogen plasma is performed once every four cycles. "HH P-H2" shows the composition of the insulating film when the modification with hydrogen plasma is performed once per cycle.

As shown in FIG. 4, the composition of the insulating film can be adjusted by adjusting the frequency of modification by hydrogen plasma. For example, by increasing the frequency of modification by hydrogen plasma (decreasing XY), the proportion of C can be decreased and the proportion of O can be increased. Further, by reducing the frequency of modification by hydrogen plasma (increasing XY), the proportion of C can be increased and the proportion of O can be decreased. In "non-plasma", the ratio of O is higher than that in "Low P-H2". This is because the insulating film that has not been modified by hydrogen plasma is a coarse film, and the insulating film is naturally oxidized when the wafer W is carried out and exposed to the atmospheric space in the processing container 1. Is.

Next, the relationship between the RF power of the reforming step and the composition of the insulating film will be described with reference to FIG. FIG. 5 is an example of a graph showing the frequency of the reforming step and the relationship between the RF power and the composition of the insulating film. In FIG. 5, "non-plasma", "Low P-H2", "Mid P-H2", "High P-H2", and "HH P-H2" are the same as in FIG. Further, "Low P-H2" shows the composition of the insulating film when the RF power is 200 W and 500 W. "Mid P-H2" shows the composition of the insulating film when the RF power is 100 W, 200 W and 500 W. "High P-H2" shows the composition of the insulating film when the RF power is 100 W and 200 W. "HH P-H2" shows the composition of the insulating film when the RF power is 200 W.

In this way, the composition of the insulating film can be adjusted by adjusting the RF power in the reforming process using hydrogen plasma. For example, by increasing the RF power, the proportion of C can be decreased and the proportion of O can be increased. Further, by lowering the RF power, the proportion of C can be increased and the proportion of O can be decreased.

Further, the composition of the insulating film can be adjusted by adjusting the processing time in the reforming step using hydrogen plasma. For example, by lengthening the processing time, the proportion of C can be decreased and the proportion of O can be increased. Further, by shortening the processing time, the proportion of C can be increased and the proportion of O can be decreased.

Next, the relationship between the dielectric constant and the film density will be described with reference to FIGS. 6 and 7. FIG. 6 is an example of a graph showing the relationship between the frequency of the reforming step, the relative permittivity of the insulating film, and the film density. FIG. 7 is an example of a graph showing the frequency of the reforming step and the relationship between the RF power and the relative permittivity and the film density of the insulating film. The value of the relative permittivity k is indicated by a black circle, and the film density is indicated by a bar graph. In addition, in FIGS. 6 and 7, "non-plasma", "Low P-H2", "Mid P-H2", "High P-H2", and "HH P-H2" are the same as in FIG. Is. In FIG. 7, the RF power is the same as in FIG.

As shown in FIGS. 6 and 7, the effect of controlling the dielectric constant can be seen by the reforming step using hydrogen plasma. In addition, the effect of improving the film density can be seen by the reforming process using hydrogen plasma. Therefore, according to the disclosure according to the present invention, an insulating film having high wet etching resistance is formed by increasing the film density while controlling the dielectric constant by adjusting the composition of the produced film. can do.

Although the case where the SiOCN film shown in FIG. 2 is formed has been described as an example, the same applies to the case where the SiCN film shown in FIG. 3 is formed.

Although the substrate processing method by the substrate processing apparatus 100 has been described above, the present disclosure is not limited to the above-described embodiment and the like, and various modifications are made within the scope of the gist of the present disclosure described in the claims. , Improvement is possible.

Although the substrate processing apparatus 100 has been described as generating capacitively coupled plasma, the plasma generation mechanism is not limited to this. For example, it may be a remote plasma.

Further, the correlation between the frequency of the reforming step and the composition of the insulating film formed on the wafer W is obtained in advance, and the frequency of the reforming step is determined based on the required composition and correlation of the insulating film. You may choose. Further, the correlation between the RF power (plasma output) of the reforming process and the composition of the insulating film formed on the wafer W is obtained in advance, and the modification is made based on the required insulating film composition and correlation. The RF power (plasma output) of the quality process may be selected. Further, the correlation between the processing time (plasma processing time) of the reforming step and the composition of the insulating film formed on the wafer W is obtained in advance, and the correlation is based on the required insulating film composition and correlation. The processing time (plasma processing time) of the reforming step may be selected.

In the flow shown in FIG. 2, it has been described that the first reaction gas is a nitride gas and the second reaction gas is an oxidation gas, but the present invention is not limited to this. The first reaction gas may be an oxidation gas and the second reaction gas may be a nitride gas. Further, the first reaction gas and the second reaction gas may be other gases. Further, in the flow shown in FIG. 3, it has been described that the first reaction gas is a nitride gas, but the present invention is not limited to this. The first reaction gas may be an oxidizing gas. Further, the first reaction gas may be another gas.

Further, in the flow shown in FIGS. 2 and 3, the frequency of modification by hydrogen plasma (XY in FIG. 2 and X in FIG. 3) has been described as being constant, but the present invention is not limited to this. For example, the frequency of modification by hydrogen plasma may be gradually reduced. Further, the frequency of modification by hydrogen plasma may be gradually increased. Further, the RF power and / or the RF time may be gradually reduced (shortened) for each cycle without changing the modification frequency with hydrogen plasma. Further, the RF power and / or the RF time may be gradually increased (longer) for each cycle without changing the modification frequency with hydrogen plasma. Further, the modification frequency may be changed and the RF power and / or RF time may be changed for each cycle.

This makes it possible to adjust the composition of the produced film in the film thickness direction. For example, the vicinity of the surface of the formed film is densified to improve the wet etching resistance, and the inside of the film can be controlled to have a low dielectric constant.

1 Processing container 2 Mounting table 3 Shower head 4 Exhaust unit 5 Gas supply mechanism 8 RF power supply unit 9 Control unit 51a Pre-cassor gas supply source 52a First reaction gas supply source 53a Second reaction gas supply source 54a Hydrogen gas supply source 55a, 56a Carrier gas / purge gas supply source 100 Substrate processing device W Wafer (substrate)

Claims (10)

A film is formed on the substrate by repeating a cycle including a step of supplying a raw material gas containing silicon, carbon, and halogen to the substrate and a step of supplying the first reaction gas to the substrate at least once. Process and
A substrate processing method comprising a step of exposing the substrate to plasma of a hydrogen-containing gas to modify the film formed on the substrate. The cycle including the step of forming the film on the substrate and the step of modifying the film is repeated at least once.
The substrate processing method according to claim 1. The step of forming a film on the substrate is
A step of repeating the cycle including the step of supplying the raw material gas to the substrate and the step of supplying the first reaction gas to the substrate at least once.
It comprises a step of supplying a second reaction gas different from the first reaction gas to the substrate.
The substrate processing method according to claim 1 or 2. The step of forming a film on the substrate is
A step of repeating the cycle including the step of supplying the raw material gas to the substrate and the step of supplying the first reaction gas to the substrate at least once.
The cycle including the step of supplying the second reaction gas different from the first reaction gas to the substrate is repeated at least once.
The substrate processing method according to claim 3. The first reaction gas is a nitrogen-containing gas and is
The second reaction gas is an oxygen-containing gas.
The substrate processing method according to claim 3 or 4. The plasma in the step of modifying the film includes a remote plasma.
The substrate processing method according to any one of claims 1 to 5. The step of modifying the membrane is a step of modifying the membrane with respect to the number of times the cycle including the step of supplying the raw material gas and the step of supplying the first reaction gas in the step of forming the membrane on the substrate is repeated. The frequency is selected based on the correlation between the frequency of the film and the composition of the film formed on the substrate.
The substrate processing method according to any one of claims 1 to 6. In the step of modifying the film, the plasma output is selected based on the correlation between the plasma output in the step of modifying the film and the composition of the film formed on the substrate.
The substrate processing method according to any one of claims 1 to 7. In the step of modifying the film, the plasma processing time is selected based on the correlation between the plasma processing time in the step of modifying the film and the composition of the film formed on the substrate.
The substrate processing method according to any one of claims 1 to 8. With the processing container
A mounting portion provided in the processing container on which the substrate is mounted, and a mounting portion.
A gas supply unit that supplies gas into the processing container,
A high frequency power supply for generating plasma,
With a control unit,
The control unit
A step of supplying a raw material gas containing silicon, carbon, and halogen from the gas supply unit to the substrate placed on the above-mentioned mounting unit, and a first reaction gas from the gas supply unit to the substrate. A step of forming a film on the substrate by repeating a cycle including a step of supplying at least once, and a step of forming a film.
The hydrogen-containing gas supplied from the gas supply unit and the high-frequency power source are used to generate plasma of the hydrogen-containing gas, the substrate is exposed to the plasma of the hydrogen-containing gas, and the film formed on the substrate is exposed. A substrate processing device that executes the reforming process.

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