Film forming method and film forming apparatus

Abstract

A film forming method according to one embodiment of the present disclosure comprises: preparing a substrate that has a first region in which a first silicon oxide film is provided and a second region in which a silicon film is provided; removing a natural oxide film that is formed on the surface of the silicon film by supplying a halogen-containing gas to the substrate; causing a metal catalyst-containing substance to be selectively adsorbed on the surface of the first silicon oxide film with respect to the surface of the silicon film by supplying a metal catalyst-containing gas to the substrate from which the natural oxide film has been removed; and forming a second silicon oxide film by reacting a silanol-containing gas with the metal catalyst-containing substance adsorbed on the surface of the first silicon oxide film by supplying the silanol-containing gas to the substrate on which the metal catalyst-containing substance has been adsorbed.

Description

Film deposition method and film deposition apparatus

[0001] This disclosure relates to a film deposition method and a film deposition apparatus.

[0002] Patent documents 1 and 2 disclose a technique in which an inhibitory layer that inhibits the adsorption of a metal catalyst-containing gas is selectively formed on the surface of a conductive film relative to the surface of an insulating film, and then a silicon oxide film is formed on the surface of the insulating film while the formation of a silicon oxide film on the surface of the conductive film is inhibited by the inhibitory layer.

[0003] Japanese Patent Publication No. 2023-182324 Japanese Patent Publication No. 2024-81396

[0004] This disclosure provides a technology that allows for the selective formation of a silicon oxide film on the surface of a silicon oxide film relative to the surface of a silicon film.

[0005] A film formation method according to one aspect of the present disclosure comprises: preparing a substrate having a first region on which a first silicon oxide film is provided and a second region on which a silicon film is provided; supplying a halogen-containing gas to the substrate to remove a native oxide film formed on the surface of the silicon film; supplying a metal catalyst-containing gas to the substrate from which the native oxide film has been removed to selectively adsorb a metal catalyst-containing substance onto the surface of the silicon film and the surface of the first silicon oxide film; and supplying a silanol-containing gas to the substrate on which the metal catalyst-containing substance is adsorbed to form a second silicon oxide film by reacting the silanol-containing gas with the metal catalyst-containing substance adsorbed on the surface of the first silicon oxide film.

[0006] According to this disclosure, a silicon oxide film can be selectively formed on the surface of a silicon oxide film relative to the surface of a silicon film.

[0007] This is a flowchart showing a film deposition method according to an embodiment. This is a cross-sectional view showing a film deposition method according to an embodiment. This is a cross-sectional view showing a film deposition method according to an embodiment. This is a cross-sectional view showing a film deposition method according to an embodiment. This is a cross-sectional view showing a film deposition method according to an embodiment. This is a cross-sectional view showing a film deposition method according to a modified embodiment. This is a cross-sectional view showing a film deposition method according to a modified embodiment. This is a cross-sectional view showing a film deposition method according to a modified embodiment. This is a plan view showing a film deposition apparatus according to an embodiment. This is a cross-sectional view showing an example of the first processing unit in Figure 4. This is a diagram comparing the thickness of silicon oxide films.

[0008] Hereinafter, exemplary embodiments of the present disclosure, not limited to those described herein, will be described with reference to the attached drawings. In all attached drawings, identical or corresponding members or components are denoted by the same or corresponding reference numerals, and redundant descriptions are omitted.

[0009] [Film Formation Method] The film formation method according to the embodiment will be described with reference to Figures 1 and 2A to 2D. Figure 1 is a flowchart showing the film formation method according to the embodiment. Figures 2A to 2D are cross-sectional views showing the film formation method according to the embodiment. The film formation method according to the embodiment includes steps S1 to S7 shown in Figure 1.

[0010] In step S1, the substrate 10 is prepared as shown in Figure 2A. The substrate 10 has a first region A1 on which a first silicon oxide film 11 is provided, and a second region A2 on which a silicon film 12 is provided. The first silicon oxide film 11 is, for example, a thermal oxide film. A native oxide film 13 is formed on the surface of the silicon film 12. The native oxide film 13 also includes a chemical oxide film formed in a solution or the like.

[0011] In step S2, hydrogen fluoride (HF) gas and ammonia (NH) gas are applied to the substrate 10. ３ ) Gas is supplied. As a result, the native oxide film 13 is altered by reacting with hydrogen fluoride gas and ammonia gas, and the reaction product is ammonium silicofluoride [(NH ４ ) ２ SiF ６] is generated. Hydrogen fluoride gas is an example of a fluorine-containing gas, and ammonia gas is an example of a basic gas. The temperature of the substrate 10 in step S2 may be 10°C or more and 150°C or less, for example, 30°C.

[0012] In step S3, the reaction products generated in step S2 are sublimated. This removes the native oxide film 13 formed on the surface of the silicon film 12, as shown in Figure 2B. For example, the reaction products are sublimated by a heat treatment in which the substrate 10 is heated and hydrogen gas is supplied to the substrate 10. Argon gas or nitrogen gas may be used instead of hydrogen gas. The reaction products are also sublimated by a plasma treatment in which the substrate 10 is heated and plasma generated from hydrogen gas is supplied to the substrate 10. Plasma generated from argon gas or plasma generated from nitrogen gas may be used instead of plasma generated from hydrogen gas. The temperature of the substrate 10 in step S3 may be 100°C or more and 200°C or less, for example, 150°C.

[0013] In step S4, trimethylaluminum (TMA) gas is supplied to the substrate 10 from which the native oxide film 13 has been removed. Trimethylaluminum gas is an example of a metal catalyst-containing gas, and trimethylaluminum is an example of a metal catalyst-containing substance. After steps S2 and S3, most of the surface of the silicon film 12 is terminated with Si-H groups and Si-F groups. In contrast, after steps S2 and S3, most of the surface of the first silicon oxide film 11 is terminated with hydroxyl groups (OH groups). Trimethylaluminum is less likely to adsorb to surfaces terminated with Si-H groups and Si-F groups, but is more likely to adsorb to surfaces terminated with OH groups. Therefore, when trimethylaluminum gas is supplied to the substrate 10 from which the native oxide film 13 has been removed, trimethylaluminum 14 is selectively adsorbed to the surface of the first silicon oxide film 11 relative to the surface of the silicon film 12, as shown in Figure 2C. The temperature of the substrate 10 in step S4 may be 100°C or higher and 200°C or lower, for example, 150°C.

[0014] In step S5, TPSOL (Tris(tert-pentoxy)silanol) gas is supplied to the substrate 10 on which trimethylaluminum 14 is adsorbed, thereby forming a second silicon oxide film 15 from the TPSOL gas. TPSOL gas is an example of a silanol-containing gas that includes a silanol group (Si-OH). The reaction for forming the second silicon oxide film 15 from the TPSOL gas (e.g., dehydration reaction of the silanol group) is promoted by trimethylaluminum 14. Trimethylaluminum 14 is selectively adsorbed on the surface of the first silicon oxide film 11 relative to the surface of the silicon film 12. Therefore, as shown in Figure 2D, the second silicon oxide film 15 can be selectively formed on the surface of the first silicon oxide film 11. The temperature of the substrate 10 in step S5 may be 100°C or more and 200°C or less, for example, 150°C.

[0015] In step S6, it is determined whether steps S4 and S5 have been performed a first time. If the number of times performed has not reached the first time (NO in step S6), the process returns to step S4 and steps S4 and S5 are performed again. If TPSOL gas is continuously supplied in step S5, the trimethylaluminum 14 adsorbed on the surface of the first silicon oxide film 11 will be depleted. Therefore, by repeating steps S4 and S5, the trimethylaluminum 14 adsorbed on the surface of the first silicon oxide film 11 is replenished, and the formation of the second silicon oxide film 15 on the surface of the first silicon oxide film 11 is promoted. As a result, the second silicon oxide film 15 can be made thicker. If the number of times performed has reached the first time (YES in step S6), the process proceeds to step S7.

[0016] In step S7, it is determined whether steps S2 to S6 have been performed a second time. If the number of executions has not reached the second time (NO in step S7), the process returns to step S2, and steps S2 to S6 are performed again. In step S4, a small amount of trimethylaluminum 14 may be adsorbed on the surface of the silicon film 12. In this case, a silicon oxyoxide film 15 is formed on the surface of the silicon film 12 in step S5. Therefore, by performing steps S2 and S3 again, the trimethylaluminum 14 adsorbed on the surface of the silicon film 12 and the silicon oxyoxide film 15 formed on the surface of the silicon film 12 can be removed. After that, steps S4 and S5 are performed, allowing the silicon oxyoxide film 15 to be formed on the surface of the first silicon oxide film 11. In this way, the formation of the silicon oxyoxide film 15 on the surface of the first silicon oxide film 11 can be inhibited while the silicon oxyoxide film 15 formed on the surface of the silicon film 12 can be made thicker. If the number of executions has reached the second time (YES in step S7), the process is terminated.

[0017] Referring to Figures 3A to 3D, a film-forming method according to a modified embodiment will be described. Figures 3A to 3D are cross-sectional views showing a film-forming method according to a modified embodiment. The film-forming method according to a modified embodiment includes steps S1 to S7 shown in Figure 1.

[0018] The film-forming method according to the modified embodiment differs from the film-forming method according to the embodiment in that the substrate 10 has a first region A1 on which a first silicon oxide film 11 is provided, a second region A2 on which a silicon film 12 is provided, and a third region A3 on which a silicon nitride film 16 is formed. The processing conditions for each step in the film-forming method according to the modified embodiment are the same as, for example, the processing conditions for each step in the film-forming method according to the embodiment. The following will mainly describe the differences from the film-forming method according to the embodiment.

[0019] In step S1, the substrate 10 is prepared as shown in Figure 3A. The substrate 10 has a first region A1 on which a first silicon oxide film 11 is provided, a second region A2 on which a silicon film 12 is provided, and a third region A3 on which a silicon nitride film 16 is provided. A native oxide film 13 is formed on the surface of the silicon film 12. A native oxide film 17 is formed on the surface of the silicon nitride film 16. The native oxide films 13 and 17 also include chemical oxide films formed in a solution or the like.

[0020] In step S2, hydrogen fluoride gas and ammonia gas are supplied to the substrate 10. As a result, the native oxide film 13 and the native oxide film 17 are altered by reacting with the hydrogen fluoride gas and ammonia gas, and ammonium silicofluoride, which is the reaction product, is generated.

[0021] In step S3, the reaction products generated in step S2 are sublimated. This removes the native oxide film 13 and the native oxide film 17, as shown in Figure 3B. For example, the reaction products are sublimated by a heat treatment in which the substrate 10 is heated and hydrogen gas is supplied to the substrate 10. Alternatively, the reaction products may be sublimated by a plasma treatment in which the substrate 10 is heated and plasma generated from hydrogen gas is supplied to the substrate 10.

[0022] In step S4, trimethylaluminum gas is supplied to the substrate 10 from which the native oxide films 13 and 17 have been removed. After steps S2 and S3, most of the surfaces of the silicon film 12 and silicon nitride film 16 are terminated with Si-H groups and Si-F groups. In contrast, after steps S2 and S3, most of the surface of the first silicon oxide film 11 is terminated with OH groups. Trimethylaluminum is less likely to adsorb to surfaces terminated with Si-H groups and Si-F groups, but more likely to adsorb to surfaces terminated with OH groups. Therefore, when trimethylaluminum gas is supplied to the substrate 10 from which the native oxide films 13 and 17 have been removed, trimethylaluminum 14 is selectively adsorbed to the surface of the first silicon oxide film 11, as shown in Figure 3C.

[0023] In step S5, TPSOL gas is supplied to the substrate 10 on which trimethylaluminum 14 is adsorbed, thereby forming a second silicon oxide film 15 from the TPSOL gas. The reaction for forming the second silicon oxide film 15 from the TPSOL gas (e.g., dehydration reaction of silanol groups) is promoted by trimethylaluminum 14. Trimethylaluminum 14 is selectively adsorbed on the surface of the first silicon oxide film 11 relative to the surface of the silicon film 12 and the surface of the silicon nitride film 16. Therefore, as shown in Figure 3D, the second silicon oxide film 15 can be selectively formed on the surface of the first silicon oxide film 11.

[0024] In step S6, it is determined whether steps S4 and S5 have been performed a first time. If the number of times performed has not reached the first time (NO in step S6), the process returns to step S4 and steps S4 and S5 are performed again. If TPSOL gas is continuously supplied in step S5, the trimethylaluminum 14 adsorbed on the surface of the first silicon oxide film 11 will be depleted. Therefore, by repeating steps S4 and S5, the trimethylaluminum 14 adsorbed on the surface of the first silicon oxide film 11 is replenished, and the formation of the second silicon oxide film 15 on the surface of the first silicon oxide film 11 is promoted. As a result, the second silicon oxide film 15 can be made thicker. If the number of times performed has reached the first time (YES in step S6), the process proceeds to step S7.

[0025] In step S7, it is determined whether steps S2 to S6 have been performed a second time. If the number of executions has not reached the second time (NO in step S7), the process returns to step S2, and steps S2 to S6 are performed again. In step S4, a small amount of trimethylaluminum 14 may be adsorbed on the surface of the silicon film 12 and the silicon nitride film 16. In this case, in step S5, a second silicon oxide film 15 is formed on the surface of the silicon film 12 and the silicon nitride film 16. Therefore, by performing steps S2 and S3 again, the trimethylaluminum 14 adsorbed on the surface of the silicon film 12 and the silicon nitride film 16, as well as the second silicon oxide film 15 on the surface of the silicon film 12 and the silicon nitride film 16, can be removed. After that, steps S4 and S5 are performed to form a second silicon oxide film 15 on the surface of the first silicon oxide film 11. Therefore, the formation of the second silicon oxide film 15 on the surface of the first silicon oxide film 11 can be thickened while inhibiting the formation of the second silicon oxide film 15 on the surface of the silicon film 12 and the silicon nitride film 16. If the number of operations has reached the second operation (YES in step S7), the process is terminated.

[0026] [Film Deposition Apparatus] A film deposition apparatus 100 for carrying out the above film deposition method will be described with reference to Figure 4. Figure 4 is a plan view showing the film deposition apparatus 100 according to the embodiment.

[0027] As shown in Figure 4, the film deposition apparatus 100 includes a first processing unit 200A, a second processing unit 200B, a third processing unit 200C, a fourth processing unit 200D, a transport unit 400, and a control unit 500. The first processing unit 200A performs step S2 in Figure 1. The second processing unit 200B performs step S3 in Figure 1. The third processing unit 200C performs step S4 in Figure 1. The fourth processing unit 200D performs step S5 in Figure 1. The first processing unit 200A, the second processing unit 200B, the third processing unit 200C, and the fourth processing unit 200D may have the same structure or different structures. Two or more steps, S2, S3, S4, and S5, may be performed in the same processing unit.

[0028] The transport unit 400 transports the substrate 10 to the first processing unit 200A, the second processing unit 200B, the third processing unit 200C, and the fourth processing unit 200D. The control unit 500 controls the first processing unit 200A, the second processing unit 200B, the third processing unit 200C, the fourth processing unit 200D, and the transport unit 400.

[0029] The transport unit 400 includes a first transport chamber 401 and a first transport mechanism 402. The internal atmosphere of the first transport chamber 401 is an atmospheric atmosphere. The first transport mechanism 402 is provided inside the first transport chamber 401. The first transport mechanism 402 includes an arm 403 for holding the substrate 10 and travels along a rail 404. The rail 404 extends in the direction of the arrangement of the carriers C.

[0030] The transport unit 400 includes a second transport chamber 411 and a second transport mechanism 412. The internal atmosphere of the second transport chamber 411 is a vacuum atmosphere. The second transport mechanism 412 is provided inside the second transport chamber 411. The second transport mechanism 412 includes an arm 413 for holding the substrate 10, and the arm 413 is arranged to be movable in the vertical and horizontal directions and rotatable about a vertical axis. The first processing unit 200A, the second processing unit 200B, the third processing unit 200C, and the fourth processing unit 200D are connected to the second transport chamber 411 via different gate valves G.

[0031] The conveying section 400 has a load lock chamber 421 between the first conveying chamber 401 and the second conveying chamber 411. The internal atmosphere of the load lock chamber 421 is switched between a vacuum atmosphere and an atmospheric atmosphere by a pressure regulating mechanism (not shown). This allows the inside of the second conveying chamber 411 to always be maintained in a vacuum atmosphere. It also prevents gas from flowing from the first conveying chamber 401 into the second conveying chamber 411. Gate valves G are provided between the first conveying chamber 401 and the load lock chamber 421, and between the second conveying chamber 411 and the load lock chamber 421.

[0032] The control unit 500 is, for example, a computer and includes a CPU (Central Processing Unit) 501 and a storage medium 502 such as memory. The storage medium 502 stores programs that control various processes performed in the film deposition apparatus 100. The control unit 500 controls the operation of the film deposition apparatus 100 by causing the CPU 501 to execute the programs stored in the storage medium 502. The control unit 500 controls the first processing unit 200A, the second processing unit 200B, the third processing unit 200C, the fourth processing unit 200D, and the transport unit 400 to carry out the above-described film deposition method.

[0033] Next, the operation of the film deposition apparatus 100 will be described. First, the first transport mechanism 402 removes the substrate 10 from the carrier C, transports the removed substrate 10 to the load lock chamber 421, and exits the load lock chamber 421. Next, the internal atmosphere of the load lock chamber 421 is switched from an atmospheric atmosphere to a vacuum atmosphere. After that, the second transport mechanism 412 removes the substrate 10 from the load lock chamber 421 and transports the removed substrate 10 to the first processing unit 200A.

[0034] Next, the first processing unit 200A performs step S2. After that, the second transport mechanism 412 removes the substrate 10 from the first processing unit 200A and transports the removed substrate 10 to the second processing unit 200B. During this time, the surrounding atmosphere of the substrate 10 can be maintained in a vacuum atmosphere, and unintended oxidation of the substrate 10 can be suppressed.

[0035] Next, the second processing unit 200B performs step S3. After that, the second transport mechanism 412 removes the substrate 10 from the second processing unit 200B and transports the removed substrate 10 to the third processing unit 200C. During this time, the surrounding atmosphere of the substrate 10 can be maintained in a vacuum atmosphere, and unintended oxidation of the substrate 10 can be suppressed.

[0036] Next, the third processing unit 200C performs step S4. After that, the second transport mechanism 412 removes the substrate 10 from the third processing unit 200C and transports the removed substrate 10 to the fourth processing unit 200D. During this time, the surrounding atmosphere of the substrate 10 can be maintained in a vacuum atmosphere, and unintended oxidation of the substrate 10 can be suppressed.

[0037] Next, the fourth processing unit 200D performs step S5. Subsequently, the control unit 500 determines whether steps S4 and S5 have been performed the first number of times. If the number of executions has not reached the first number of times, the second transfer mechanism 412 takes out the substrate 10 from the fourth processing unit and transfers the taken-out substrate 10 to the third processing unit 200C. Thereafter, the control unit 500 controls the third processing unit 和 the fourth processing unit 200D and the transfer unit 400 to perform steps S4 and S5 again.

[0038] On the other hand, if the number of executions has reached the first number of times, the control unit 500 determines whether steps S2 to S6 have been performed the second number of times. If the number of executions has not reached the second number of times, the second transfer mechanism 412 takes out the substrate 10 from the fourth processing unit 200D and transfers the taken-out substrate 10 to the first processing unit 200A. Thereafter, the control unit 500 controls the first processing unit 200A, the second processing unit 200B, the third processing unit 200C, the fourth processing unit 200D, and the transfer unit 400 to perform steps S2 to S6 again.

[0039] On the other hand, if the number of executions has reached the second number of times, the second transfer mechanism 412 takes out the substrate 10 from the fourth processing unit 200D, transfers the taken-out substrate 10 to the load lock chamber 421, and exits from the load lock chamber 421. Subsequently, the internal atmosphere of the load lock chamber 421 is switched from a vacuum atmosphere to an atmospheric atmosphere. Thereafter, the first transfer mechanism 402 takes out the substrate 10 from the load lock chamber 421 and accommodates the taken-out substrate 10 in the carrier C. Then, the processing of the substrate 10 is completed.

[0040] Referring to FIG. 5, the first processing unit 200A will be described. FIG. 5 is a cross-sectional view showing an example of the first processing unit 200A in FIG. 4. Since the second processing unit 200B, the third processing unit 200C, and the fourth processing unit 200D are configured in the same manner as the first processing unit 200A, illustration and description thereof are omitted.

[0041] The first processing unit 200A includes an airtight processing container 210 having a substantially cylindrical shape. An exhaust chamber 211 is provided at the center of the bottom wall of the processing container 210. The exhaust chamber 211 has, for example, a substantially cylindrical shape protruding downward. An exhaust pipe 212 is connected to the exhaust chamber 211, for example, on the side surface of the exhaust chamber 211.

[0042] An exhaust source 272 is connected to the exhaust pipe 212 via a pressure controller 271. The pressure controller 271 includes a pressure adjustment valve such as a butterfly valve. The exhaust pipe 212 is configured to be able to decompress the inside of the processing container 210 by the exhaust source 272. The pressure controller 271 and the exhaust source 272 constitute a gas discharge mechanism 270 for discharging the gas inside the processing container 210.

[0043] A transfer port 215 is provided on the side surface of the processing container 210. The transfer port 215 is opened and closed by a gate valve G. The loading and unloading of the substrate 10 between the inside of the processing container 210 and the second transfer chamber 411 (see FIG. 4) is performed via the transfer port 215.

[0044] Inside the processing container 210, a stage 220, which is a holding unit for holding the substrate 10, is provided. The stage 220 holds the substrate 10 horizontally with the substrate surface 10a facing upward. The stage 220 is formed in a substantially circular shape in plan view and is supported by a support member 221. On the surface of the stage 220, a substantially circular recess 222 for placing a substrate 10 having a diameter of, for example, 300 mm is formed. The recess 222 has an inner diameter slightly larger than the diameter of the substrate 10. The depth of the recess 222 is configured to be substantially the same as the thickness of the substrate 10, for example. The stage 220 is formed of a ceramic material such as aluminum nitride (AlN), for example. The stage 220 may be formed of a metal material such as nickel (Ni). Instead of the recess 222, a guide ring for guiding the substrate 10 may be provided at the peripheral edge of the surface of the stage 220.

[0045] A lower electrode 223, for example, grounded, is embedded in the stage 220. A heating mechanism 224 is embedded below the lower electrode 223. The heating mechanism 224 is powered by a power supply unit (not shown) based on a control signal from the control unit 500 (see Figure 4), and heats the substrate 10 placed on the stage 220 to a set temperature. If the entire stage 220 is made of metal, the entire stage 220 functions as the lower electrode, so the lower electrode 223 does not need to be embedded in the stage 220. The stage 220 is provided with a plurality (for example, three) of lifting pins 231 for holding and raising / lowering the substrate 10 placed on the stage 220. The material of the lifting pins 231 is, for example, alumina (Al ２ O ３ The material may be ceramics such as quartz or other similar materials. The lower end of the lifting pin 231 is attached to the support plate 232. The support plate 232 is connected to a lifting mechanism 234 provided outside the processing container 210 via a lifting shaft 233.

[0046] The lifting mechanism 234 is installed, for example, at the bottom of the exhaust chamber 211. The bellows 235 is provided between the opening 219 for the lifting shaft 233 formed on the lower surface of the exhaust chamber 211 and the lifting mechanism 234. The shape of the support plate 232 may be such that it can move up and down without interfering with the support member 221 of the stage 220. The lifting pin 231 is configured to move up and down between the upper surface of the stage 220 and the lower surface of the stage 220 by the lifting mechanism 234.

[0047] A gas supply unit 240 is provided on the top wall 217 of the processing container 210 via an insulating member 218. The gas supply unit 240 forms the upper electrode and faces the lower electrode 223. A high-frequency power supply 252 is connected to the gas supply unit 240 via a matching unit 251. By supplying high-frequency power of 450 kHz to 100 MHz from the high-frequency power supply 252 to the upper electrode (gas supply unit 240), a high-frequency electric field is generated between the upper electrode (gas supply unit 240) and the lower electrode 223, and a capacitively coupled plasma is generated. The plasma generation unit 250 that generates the plasma includes a matching unit 251 and a high-frequency power supply 252. The plasma generation unit 250 is not limited to generating capacitively coupled plasma, but may generate other plasmas such as inductively coupled plasma. In steps that do not generate plasma (for example, steps S2, S4, and S5), it is not necessary for the gas supply unit 240 to form the upper electrode, and the lower electrode 223 is also unnecessary.

[0048] The gas supply unit 240 includes a hollow gas supply chamber 241. On the lower surface of the gas supply chamber 241, numerous holes 242 are evenly arranged, for example, to distribute and supply the processing gas into the processing container 210. Above the gas supply chamber 241 in the gas supply unit 240, for example, a heating mechanism 243 is embedded. The heating mechanism 243 is heated to a set temperature by being powered from a power supply unit (not shown) based on a control signal from the control unit 500.

[0049] A gas supply mechanism 260 is connected to the gas supply chamber 241 via a gas supply passage 261. The gas supply mechanism 260 supplies the gas used in at least one of steps S2 to S5 in Figure 1 to the gas supply chamber 241 via the gas supply passage 261. Although not shown, the gas supply mechanism 260 includes individual piping for each type of gas, an on / off valve installed in the middle of the individual piping, and a flow controller installed in the middle of the individual piping. When the on / off valve opens the individual piping, gas is supplied from the supply source to the gas supply passage 261. The amount of gas supplied is controlled by the flow controller. On the other hand, when the on / off valve closes the individual piping, the supply of gas from the supply source to the gas supply passage 261 is stopped.

[0050] [Experimental Results] A substrate having a silicon film and a silicon oxide film on its surface was prepared using the film formation method according to the embodiment described above, and a silicon oxide film was formed on the prepared substrate. Subsequently, the thickness of the silicon oxide film formed on the substrate was measured using an ellipsometer.

[0051] In this experiment, the method for sublimating the reaction product in step S3 of the film formation method according to the embodiment, and the type of gas supplied when sublimating the reaction product were changed. The method for sublimating the reaction product is thermal sublimation or plasma sublimation. Thermal sublimation is a method of sublimating the reaction product by heat treatment, in which the substrate is heated and gas is supplied to the substrate. Plasma sublimation is a method of sublimating the reaction product by plasma treatment, in which the substrate is heated and plasma generated from gas is supplied to the substrate. In this experiment, the native oxide film 13 was removed under the following six conditions P1 to P6.

[0052] (Condition P1) Sublimation method: Heat sublimation; Gas type: Hydrogen gas (Condition P2) Sublimation method: Heat sublimation; Gas type: Argon gas (Condition P3) Sublimation method: Heat sublimation; Gas type: Nitrogen gas (Condition P4) Sublimation method: Plasma sublimation; Gas type: Hydrogen gas (Condition P5) Sublimation method: Plasma sublimation; Gas type: Argon gas (Condition P6) Sublimation method: Plasma sublimation; Gas type: Nitrogen gas

[0053] Figure 6 shows a comparison of the thickness of silicon oxide films. In Figure 6, the results for conditions P1, P2, P3, P4, P5, and P6 are shown from left to right. In each condition in Figure 6, the bar graph represented by a downward-sloping diagonal line shows the thickness of the silicon oxide film formed on the surface of the silicon oxide film, and the bar graph represented by an upward-sloping diagonal line shows the thickness of the silicon oxide film formed on the surface of the silicon film. In Figure 6, for each condition, the thickness of the silicon oxide film is shown as a relative value with the thickness of the silicon oxide film formed on the surface of the silicon oxide film set to 1.

[0054] As shown in FIG. 6, it can be seen that under any conditions, the thickness of the silicon oxide film formed on the surface of the silicon oxide film is thicker than the thickness of the silicon oxide film formed on the surface of the silicon film. From this result, it can be said that under any conditions, a silicon oxide film can be selectively formed on the surface of the silicon oxide film with respect to the surface of the silicon film.

[0055] As shown in FIG. 6, in the case of condition P4, the thickness of the silicon oxide film formed on the surface of the silicon film is the thinnest. From this result, it can be said that by heating the substrate and supplying plasma generated from hydrogen gas to the substrate to sublime the reaction product, the selectivity of forming a silicon oxide film on the surface of the silicon oxide film with respect to the surface of the silicon film can be enhanced.

[0056] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The above embodiments may be omitted, substituted, or changed in various forms without departing from the scope and spirit of the appended claims.

[0057] In the above embodiment, the case where the native oxide film 13 is removed by supplying hydrogen fluoride gas and ammonia gas to the substrate 10 to alter the native oxide film 13 to generate a reaction product and subliming the generated reaction product has been described, but the present disclosure is not limited thereto. For example, the native oxide film 13 may be removed by supplying a halogen-containing gas to the substrate 10. The halogen-containing gas is, for example, hydrogen fluoride (HF) gas, fluorine (F ２ ) gas, nitrogen trifluoride (NF ３ ) gas, chlorine trifluoride (ClF ３ ) gas, methane tetrafluoride (CF ４ ) gas.

[0058] The above embodiments describe a case where the metal catalyst-containing gas is trimethylaluminum gas, but the disclosure is not limited thereto. The metal catalyst-containing gas is preferably an organometallic compound gas. Specifically, examples include organoaluminum compound gases, organoboron compound gases, organogallium compound gases, and organotitanium compound gases. Examples of organoaluminum compound gases include trimethylaluminum gas, triethylaluminum (TEA) gas, dimethylaluminum chloride gas, or dimethylaluminum isopropoxide (DMAI) gas. Examples of organoboron compound gases include trimethylborane (TMB) gas, triethylborane (TEB) gas, trimethylborate gas, or triethylborate gas. Examples of organogallium compound gases include trimethylgallium (TMGa) gas or triethylgallium (TEGa) gas. Examples of organotitanium compound gases include tetrakisdimethylaminotitanium (TDMAT) gas.

[0059] In the embodiments described above, the case in which the silanol-containing gas is TPSOL gas was explained, but the disclosure is not limited thereto. The silanol-containing gas may also be triethylsilanol gas, methylbis(tert-pentoxy)silanol gas, or tris(tert-butoxy)silanol (TBSOL) gas.

[0060] This international application claims priority based on Japanese Patent Application No. 2024-158212, filed on 12 September 2024, and the entire contents of said application are incorporated herein by reference.

[0061] 10 Substrate 11 Silicon oxide film 12 Silicon film 13 Native oxide film 14 Trimethylaluminum 15 Silicon oxide film A1 First region A2 Second region

Claims

1. A film formation method comprising: preparing a substrate having a first region on which a first silicon oxide film is provided and a second region on which a silicon film is provided; supplying a halogen-containing gas to the substrate to remove a native oxide film formed on the surface of the silicon film; supplying a metal catalyst-containing gas to the substrate from which the native oxide film has been removed to selectively adsorb a metal catalyst-containing substance onto the surface of the silicon film and the surface of the first silicon oxide film; and supplying a silanol-containing gas to the substrate on which the metal catalyst-containing substance has been adsorbed to form a second silicon oxide film by reacting the silanol-containing gas with the metal catalyst-containing substance adsorbed on the surface of the first silicon oxide film.

2. The method for forming a film according to claim 1, wherein removing the native oxide film comprises: supplying a fluorine-containing gas and a basic gas to the substrate to convert the native oxide film into a reaction product; and removing the reaction product by sublimation.

3. The film formation method according to claim 2, wherein removing the reaction product by sublimation includes supplying hydrogen gas to the substrate while heating the substrate.

4. The film formation method according to claim 2, wherein removing the reaction product by sublimation includes supplying plasma generated from hydrogen gas to the substrate.

5. The film formation method according to claim 1, comprising repeatedly adsorbing the metal catalyst-containing substance and forming the second silicon oxide film in this order.

6. A film formation method according to any one of claims 1 to 5, comprising repeatedly removing the native oxide film, adsorbing the metal catalyst-containing material, and forming the second silicon oxide film in this order.

7. The method for forming a film according to any one of claims 1 to 5, wherein the substrate further has a third region on which a silicon nitride film is provided, removing the native oxide film includes removing the native oxide film formed on the surface of the silicon nitride film, adsorbing the metal catalyst-containing substance includes selectively adsorbing the metal catalyst-containing substance onto the surface of the first silicon oxide film relative to the surface of the silicon nitride film, and forming the second silicon oxide film includes reacting the silanol-containing gas with the metal catalyst-containing substance adsorbed on the surface of the first silicon oxide film to form the second silicon oxide film.

8. A film deposition apparatus comprising: a processing container for housing a substrate; a gas supply unit for supplying gas into the processing container; and a control unit, wherein the control unit is configured to control the gas supply unit to perform the following: preparing a substrate having a first region on which a first silicon oxide film is provided and a second region on which a silicon film is provided; supplying a halogen-containing gas to the substrate to remove a native oxide film formed on the surface of the silicon film; supplying a metal catalyst-containing gas to the substrate from which the native oxide film has been removed to selectively adsorb a metal catalyst-containing substance onto the surface of the silicon film and the surface of the first silicon oxide film; and supplying a silanol-containing gas to the substrate on which the metal catalyst-containing substance has been adsorbed to form a second silicon oxide film by reacting the silanol-containing gas with the metal catalyst-containing substance adsorbed on the surface of the first silicon oxide film.

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