Method for manufacturing semiconductor device, substrate processing method, recording medium, and substrate processing apparatus

Abstract

The present invention relates to a semiconductor device manufacturing method, a substrate processing method, a recording medium, and a substrate processing apparatus. When a silicon film and a silicon nitride film formed on a substrate are oxidized using a plasma-excited oxygen-containing gas, the films are selectively oxidized to form an oxide layer. The method includes (a) a step of generating reaction species by plasma-exciting a processing gas containing oxygen and hydrogen; and (b) a step of supplying the reaction species to the substrate to oxidize surfaces of the silicon film and the silicon nitride film formed on the substrate, respectively, wherein the ratio of oxygen to hydrogen contained in the processing gas is adjusted in such a manner that, in (b), the ratio of the thickness of a second oxide layer formed by oxidizing the surface of the silicon nitride film to the thickness of a first oxide layer formed by oxidizing the surface of the silicon film becomes a prescribed thickness ratio.

Description

TECHNICAL FIELD

[0001] The present application relates to a manufacturing method of a semiconductor device, a substrate processing method, a recording medium, and a substrate processing apparatus. BACKGROUND

[0002] In recent years, semiconductor devices such as flash memories have a tendency of higher integration. Along with this, pattern sizes are significantly miniaturized. In forming these patterns, as one of manufacturing processes, a process of performing a prescribed treatment such as oxidation treatment or nitridation treatment on a substrate is sometimes implemented.

[0003] For example, Patent Literature 1 and Patent Literature 2 disclose a modification treatment of a pattern surface formed on a substrate using a treatment gas excited by plasma.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: International Publication No. 2016 / 125606

[0007] Patent Literature 2: Japanese Patent Application Publication No. 2014-75579 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] It is sometimes required to selectively oxidize a silicon film and a silicon nitride film formed on a substrate to form an oxide layer.

[0010] The present application relates to a manufacturing method of a semiconductor device, a substrate processing method, a recording medium, and a substrate processing apparatus.

[0011] MEANS FOR SOLVING THE PROBLEMS

[0012] According to one embodiment of the present application, there is provided a technology including: (a) a step of generating a reaction species by plasma-exciting a treatment gas containing oxygen and hydrogen; and (b) a step of supplying the reaction species to a substrate, and oxidizing surfaces of a silicon film and a silicon nitride film respectively exposed on the substrate, wherein a ratio of oxygen to hydrogen contained in the treatment gas is adjusted in such a manner that a ratio of a thickness of a second oxide layer formed by oxidizing the surface of the silicon nitride film in (b) to a thickness of a first oxide layer formed by oxidizing the surface of the silicon film becomes a prescribed thickness ratio.

[0013] EFFECTS OF THE INVENTION

[0014] According to the present application, when oxidizing silicon film and silicon nitride film formed on a substrate using a plasma-excited oxygen-containing gas, the films can be selectively oxidized to form an oxide layer. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 A schematic configuration diagram of a substrate processing apparatus suitably used in one embodiment of the present application, and a diagram showing a processing furnace portion in a longitudinal cross-sectional view.

[0016] Figure 2 A diagram for illustrating a principle of generation of plasma in one embodiment of the present application.

[0017] Figure 3 A schematic configuration diagram of a controller of a substrate processing apparatus suitably used in one embodiment of the present application, and a diagram showing a control system of the controller in a block diagram.

[0018] Figure 4 A flowchart for showing a substrate processing procedure in one embodiment of the present application.

[0019] Figure 5 (A) of FIG. 1 is an explanatory diagram of a recessed substrate to be processed in a substrate processing procedure in one embodiment of the present application; Figure 5 (B) of FIG. 1 is an explanatory diagram of a substrate to which a substrate processing procedure in one embodiment of the present application is applied. Figure 5 (A) of FIG. 1 is an explanatory diagram of a recessed substrate to be processed in a substrate processing procedure in one embodiment of the present application;

[0020] Figure 6 A diagram for showing a modification example of a substrate processing apparatus suitably used in one embodiment of the present application.

[0021] Figure 7 A diagram for showing a relationship between a ratio of hydrogen contained in a processing gas, and an oxidation ratio of a silicon nitride film with respect to a silicon film.

[0022] REFERENCE NUMERALS

[0023] 100, 400 substrate processing apparatus

[0024] 200 wafer (substrate)

[0025] 201, 401 processing chamber

[0026] 203, 403 processing vessel

[0027] 221 controller (control section) DETAILED DESCRIPTION

[0028] <One Embodiment of the Present Invention>

[0029] One embodiment of the present application will be described below with reference to the drawings. Note that the drawings used in the following description are schematic and the dimensional relationships, the ratios of the sizes of the respective elements, and the like shown in the drawings are not necessarily the same as actual ones. In addition, even when a plurality of drawings are used, the dimensional relationships, the ratios of the sizes of the respective elements, and the like are not necessarily the same among the drawings.

[0030] [First Embodiment]

[0031] (1) Substrate processing apparatus

[0032] A substrate processing apparatus according to the first embodiment of the present application will be described below with reference to FIGS. 1A and IB. The substrate processing apparatus according to the first embodiment is configured to mainly perform oxidation treatment on a film formed on the surface of a wafer 200 serving as a substrate. Figure 1 and Figure 2 The substrate processing apparatus according to the first embodiment is configured to mainly perform oxidation treatment on a film formed on the surface of a wafer 200 serving as a substrate.

[0033] (Processing chamber)

[0034] The substrate processing apparatus 100 includes a processing furnace 202 for performing plasma treatment on the wafer 200. The processing furnace 202 includes a processing container 203 which constitutes a processing chamber 201. The processing container 203 includes an upper container 210 which is a dome-shaped first container, and a lower container 211 which is a bowl-shaped second container. The processing chamber 201 is formed by placing the upper container 210 over the lower container 211. The upper container 210 is formed of a non-metallic material such as alumina (AI2O3) or quartz (SiO2), and the lower container 211 is formed of aluminum (Al), for example.

[0035] A gate valve 244 is provided on the lower side wall of the lower container 211. The gate valve 244 is configured to allow the wafer 200 to be carried into or out of the processing chamber 201 through a carrying-in / out port 245 by a carrying mechanism (not shown) when the gate valve 244 is opened. The gate valve 244 is configured as an isolation valve which maintains the airtightness of the processing chamber 201 when closed.

[0036] The processing chamber 201 includes a plasma generation space 201a in which a resonance coil 212 is provided around, and a substrate processing space 201b which communicates with the plasma generation space 201a and in which the wafer 200 is processed. The plasma generation space 201a is a space in which plasma is generated, and is a space which is located above the lower end of the resonance coil 212 and below the upper end of the resonance coil 212 in the processing chamber. On the other hand, the substrate processing space 201b is a space in which the wafer 200 is processed using plasma, and is a space which is located below the lower end of the resonance coil 212. In the present embodiment, the plasma generation space 201a and the substrate processing space 201b are configured to have substantially the same horizontal diameter.

[0037] (holder)

[0038] In the center of the bottom side of the processing chamber 201, a holder 217 that is a substrate mounting portion on which the wafer 200 is mounted is provided. The holder 217 is formed of a non-metallic material such as aluminum nitride (AIN), ceramic, quartz, or the like, and is configured to reduce metal contamination to a film or the like formed on the wafer 200.

[0039] A heater 217b that is a heating mechanism is integrally built in the inside of the holder 217. The heater 217b is configured to heat the surface of the wafer 200 to, for example, about 25°C to 750°C when power is supplied.

[0040] The holder 217 is electrically insulated from the lower vessel 211. In order to further improve the uniformity of the density of the plasma generated on the wafer 200 mounted on the holder 217, an impedance adjustment electrode 217c is provided in the inside of the holder 217 and grounded through an impedance variable mechanism 275 that is an impedance adjustment portion. The impedance variable mechanism 275 is configured of a coil and a variable capacitor, and is configured to be able to change the impedance in a range from about 0Ω to the parasitic impedance value of the processing chamber 201 by controlling the inductance and resistance of the coil and the capacitance value of the variable capacitor. Thus, the potential (bias voltage) of the wafer 200 can be controlled by the impedance adjustment electrode 217c and the holder 217.

[0041] The holder 217 is provided with a holder lifting mechanism 268 that has a driving mechanism that lifts the holder. In addition, the holder 217 is provided with a penetration hole 217a, and the wafer lifting pin 266 is provided on the bottom surface of the lower vessel 211. The penetration hole 217a and the wafer lifting pin 266 are each provided with at least three at positions opposite to each other. When the holder 217 is lowered by the holder lifting mechanism 268, the wafer lifting pin 266 is configured to pass through the penetration hole 217a in a state of not contacting the holder 217. The substrate mounting portion according to the present embodiment is mainly configured of the holder 217, the heater 217b, and the impedance electrode 217c.

[0042] (gas supply portion)

[0043] A gas supply head 236 is provided above the processing chamber 201, that is, in the upper portion of the upper vessel 210. The gas supply head 236 is configured to have a cover body 233 that is a cover, a gas introduction port 234, a buffer chamber 237, an opening 238, a shielding plate 240, and a gas blowout port 239, and is capable of supplying a processing gas into the processing chamber 201. The buffer chamber 237 has a function as a dispersion space that disperses the processing gas introduced through the gas introduction port 234.

[0044] The downstream end of the oxygen-containing gas supply pipe 232a that supplies the oxygen (O) -containing gas, the downstream end of the hydrogen-containing gas supply pipe 232b that supplies the hydrogen (H) -containing gas, and the non-active gas supply pipe 232c that supplies the non-active gas are connected to the gas introduction port 234 in a manner that they join together. The oxygen-containing gas supply pipe 232a is provided with, in order from the upstream side, an O-containing gas supply source 250a, a mass flow controller (MFC) 252a as a flow control device, and a valve 253a as an on-off valve. The hydrogen-containing gas supply pipe 232b is provided with, in order from the upstream side, an H-containing gas supply source 250b, an MFC 252b, and a valve 253b. The non-active gas supply pipe 232c is provided with, in order from the upstream side, a non-active gas supply source 250c, an MFC 252c, and a valve 253c. On the downstream side of the oxygen-containing gas supply pipe 232a, the hydrogen-containing gas supply pipe 232b, and the non-active gas supply pipe 232c where they join together, a valve 243a is provided that is connected to the upstream end of the gas introduction port 234. The valves 253a, 253b, 253c, and 243a are opened and closed so that the flow rates of the respective gases can be adjusted by the MFCs 252a, 252b, and 252c, and the O-containing gas, the H-containing gas, the non-active gas, and the like are supplied into the processing chamber 201 through the gas supply pipes 232a, 232b, and 232c.

[0045] The processing gas supply portion (processing gas supply system) according to the present embodiment is mainly composed of the gas supply head 236 (the cover 233, the gas introduction port 234, the buffer chamber 237, the opening 238, the shielding plate 240, and the gas blowout port 239), the oxygen-containing gas supply pipe 232a, the hydrogen-containing gas supply pipe 232b, the non-active gas supply pipe 232c, the MFCs 252a, 252b, and 252c, the valves 253a, 253b, and 253c, and the valve 243a.

[0046] In addition, the oxygen-containing gas supply system according to the present embodiment is composed of the gas supply head 236, the oxygen-containing gas supply pipe 232a, the MFC 252a, the valve 253a, and the valve 243a. Furthermore, the hydrogen-containing gas supply system according to the present embodiment is composed of the gas supply head 236, the hydrogen-containing gas supply pipe 232b, the MFC 252b, the valve 253b, and the valve 243a. Furthermore, the non-active gas supply system according to the present embodiment is composed of the gas supply head 236, the non-active gas supply pipe 232c, the MFC 252c, the valve 253c, and the valve 243a.

[0047] (Exhaust portion)

[0048] On the side wall of the lower container 211, a gas exhaust port 235 for exhausting the processing gas from the processing chamber 201 is provided. On the gas exhaust port 235, an upstream end of a gas exhaust pipe 231 is connected. On the gas exhaust pipe 231, an APC (Auto Pressure Controller) valve 242 as a pressure regulator (pressure regulating portion), a valve 243b as an on-off valve, and a vacuum pump 246 as a vacuum exhaust device are provided in this order from the upstream side. The exhaust portion according to the present embodiment is mainly constituted by the gas exhaust port 235, the gas exhaust pipe 231, the APC valve 242, and the valve 243b. Note that the vacuum pump 246 can also be included in the exhaust portion.

[0049] (plasma generating portion)

[0050] On the outer side of the side wall of the upper container 210, i.e., the outer periphery of the processing chamber 201, a spiral-shaped resonance coil 212 as a first electrode is provided in a manner of surrounding the processing chamber 201. On the resonance coil 212, an RF sensor 272, a high-frequency power source 273, and a matcher 274 for matching the impedance and the output frequency of the high-frequency power source 273 are connected.

[0051] The high-frequency power source 273 is a component that supplies high-frequency electric power (RF electric power) to the resonance coil 212. The RF sensor 272 is provided on the output side of the high-frequency power source 273, and is a component that monitors the information of the forward wave and the reflected wave of the supplied high-frequency. The reflected wave electric power monitored by the RF sensor 272 is input to the matcher 274, which is a component that controls the impedance of the high-frequency power source 273 and the frequency of the output high-frequency electric power in such a manner that the reflected wave becomes minimum, based on the information of the reflected wave input from the RF sensor 272.

[0052] The high-frequency power source 273 has a power source control means (control circuit) including a high-frequency oscillation circuit for specifying the oscillation frequency and the output, and a preamplifier, and an amplifier (output circuit) for amplifying to a specified output. The power source control means controls the amplifier based on the output conditions related to the frequency and the electric power set in advance through an operation panel. The amplifier supplies a certain high-frequency electric power to the resonance coil 212 via a transmission line.

[0053] For the resonance coil 212, in order to form a standing wave of a specified wavelength, the winding diameter, the winding pitch, and the number of windings are set so as to resonate with a certain wavelength. That is, the electric length of the resonance coil 212 is set to a length corresponding to an integral multiple (1 times, 2 times,...) of the wavelength in the specified frequency of the high-frequency electric power supplied from the high-frequency power source 273.

[0054] The both ends of the resonance coil 212 are electrically grounded, and in order to finely adjust the electrical length of the resonance coil 212 at the time of initial setting of the apparatus or at the time of changing the processing conditions, at least one of the both ends is grounded via a movable tap 213. Figure 1 The mark 214 in the drawing indicates the fixed ground on the other side. The movable tap 213 adjusts the position in such a manner that the resonance characteristics of the resonance coil 212 are substantially equal to the high-frequency power source 273. Further, in order to finely adjust the impedance of the resonance coil 212 at the time of initial setting of the apparatus or at the time of changing the processing conditions, a power supply section is formed by a movable tap 215 between the both ends of the resonance coil 212 to which the ground is applied. By providing the resonance coil 212 with a variable ground section and a variable power supply section, as described later, it is possible to more easily adjust the resonance frequency and the load impedance of the processing chamber 201 during adjustment.

[0055] A shield plate 223 is provided in order to shield the electric field outside the resonance coil 212 and form the necessary capacitive component (C component) between the resonance coil 212 for constituting a resonance circuit. The shield plate 223 is generally formed in a cylindrical shape using an electrically conductive material such as an aluminum alloy.

[0056] The plasma generating section (plasma generating mechanism) according to the present embodiment is mainly constituted by the resonance coil 212, the RF sensor 272, and the matcher 274. Note that the high-frequency power source 273 can also be included as the plasma generating section.

[0057] Here, the plasma generating principle of the apparatus according to the present embodiment and the properties of the generated plasma are described. Figure 2 The plasma generating principle of the apparatus according to the present embodiment and the properties of the generated plasma are described.

[0058] The plasma generating circuit constituted by the resonance coil 212 is constituted by a parallel resonance circuit of RLC. In the case where the wavelength of the high-frequency power supplied from the high-frequency power source 273 is the same as the electrical length of the resonance coil 212, the resonance condition of the resonance coil 212 is a condition in which the reactance component formed by the capacitive component and the inductive component of the resonance coil 212 is canceled out and becomes a pure resistance. However, in the above-described plasma generating circuit, in the case where plasma is generated, the actual resonance frequency slightly varies due to variations in the capacitive coupling between the voltage section of the resonance coil 212 and the plasma, variations in the inductive coupling between the plasma generating space 201a and the plasma, the excitation state of the plasma, and the like.

[0059] Therefore, in this embodiment, the following functions are provided: in order to compensate for the resonant offset in the resonant coil 212 during plasma generation on the power supply side, the reflected wave power from the resonant coil 212 during plasma generation is detected in the RF sensor 272, and the matching unit 274 corrects the output of the high-frequency power supply 273 based on the detected reflected wave power.

[0060] Specifically, based on the reflected wave power from the resonant coil 212 detected in the RF sensor 272 during plasma generation, the matching unit 274 increases or decreases the impedance or output frequency of the high-frequency power supply 273 in a manner that minimizes the reflected wave power. When controlling the impedance, the matching unit 274 is configured with a variable capacitor control circuit that corrects for a preset impedance; when controlling the frequency, the matching unit 274 is configured with a frequency control circuit that corrects for a preset oscillation frequency of the high-frequency power supply 273. It should be noted that the high-frequency power supply 273 and the matching unit 274 can also be configured as a single unit.

[0061] Using the above structure, such as Figure 2 As shown, in the resonant coil 212 of this embodiment, since high-frequency power is supplied based on the actual resonant frequency of the resonant coil containing plasma (or, in a manner matching the actual impedance of the resonant coil containing plasma), a standing wave is formed in which the phase voltage and anti-phase voltage always cancel each other out. When the electrical length of the resonant coil 212 is the same as the wavelength of the high-frequency power, the highest phase current is generated at the electrical midpoint of the coil (the node where the voltage is zero). Therefore, near the electrical midpoint, there is almost no capacitive coupling with the processing chamber wall and the liner 217, forming an annular induced plasma with extremely low potential.

[0062] (Control Department)

[0063] The controller 221, as the control unit, is configured to control APC valves 242 and 243b and vacuum pump 246 via signal line A, the support lifting mechanism 268 via signal line B, the heater power regulating mechanism 276 and impedance variable mechanism 275 via signal line C, the gate valve 244 via signal line D, the RF sensor 272, high-frequency power supply 273 and matching device 274 via signal line E, and the MFCs 252a to 252c and valves 253a to 253c and 243a via signal line F.

[0064] like Figure 3As shown, the controller 221 as a control unit (control means) is configured in the form of a computer having a CPU (Central Processing Unit) 221a, a RAM (Random Access Memory) 221b, a storage device 221c, and an I / O port 221d. The RAM 221b, the storage device 221c, and the I / O port 221d are configured to be capable of exchanging data with the CPU 221a via an internal bus 221e. On the controller 221, an input / output device 225 configured in the form of a touch panel, a display, or the like is connected.

[0065] The storage device 221c is configured by, for example, a flash memory, an HDD (Hard Disk Drive), or the like. In the storage device 221c, a control program for controlling the operation of the substrate processing apparatus, a program recipe in which steps, conditions, and the like of the substrate processing described later are recorded, and the like are stored in a readable manner. The process recipe is composed in a manner that enables the controller 221 to execute each step in the substrate processing sequence described later and obtain a prescribed result, and functions as a program. Hereinafter, the process recipe, the control program, and the like are collectively and simply referred to as a program. Note that, in the present specification, when the term program is used, the case of the process recipe alone, the case of the control program alone, or both are included. Further, the RAM 221b is configured in the form of a storage area (work area) that temporarily holds a program, data, or the like read by the CPU 221a.

[0066] The I / O port 221d is connected to the above-described MFCs 252a to 252c, the valves 253a to 253c, 243a, 243b, the gate valve 244, the APC valve 242, the vacuum pump 246, the RF sensor 272, the high-frequency power source 273, the matcher 274, the susceptor lifting mechanism 268, the impedance variable mechanism 275, the heater power adjustment mechanism 276, and the like.

[0067] CPU 221a can be configured to read and execute control programs from storage device 221c, and read process data from storage device 221c based on inputs such as operation commands from input / output device 225. Furthermore, CPU221a is configured to control the opening adjustment of APC valve 242, the opening and closing of valve 243b, and the start / stop of vacuum pump 246 via I / O port 221d and signal line A, based on the read process information; control the lifting and lowering of liner lifting mechanism 268 via signal line B; control the power supply adjustment (temperature adjustment) to heater 217b via heater power adjustment mechanism 276 and impedance adjustment via impedance variable mechanism 275 via signal line C; control the opening and closing of gate valve 244 via signal line D; control the operation of RF sensor 272, matching device 274, and high-frequency power supply 273 via signal line E; and control the flow rate adjustment of various gases via MFCs 252a-252c and the opening and closing of valves 253a-253c and 243a via signal line F; and so on.

[0068] The controller 221 can be configured to install the aforementioned program stored in an external storage device (e.g., magnetic tape; floppy disk, hard disk, etc.; optical disc, CD, DVD, etc.; optical disk, MO, etc.; semiconductor memory, USB memory, memory card, etc.) 226 into a computer. The storage device 221c and the external storage device 226 are configured in the form of a computer-readable recording medium. Hereinafter, they will be collectively referred to simply as recording media. In this specification, when the term "recording medium" is used, sometimes only the storage device 221c is included, sometimes only the external storage device 226 is included, or sometimes both are included. It should be noted that providing the program to the computer can also be implemented without using the external storage device 226, via communication means such as a network or dedicated line.

[0069] (2) Substrate processing process

[0070] Next, we will mainly use Figure 4 The substrate processing step in one embodiment of the present invention will be described. Figure 4 This is a flowchart illustrating a substrate processing step in one embodiment of the present invention. As a step in the manufacturing process of semiconductor devices such as flash memory, the substrate processing step in one embodiment of the present invention is performed using the aforementioned substrate processing apparatus 100. In the following description, the operation of each component constituting the substrate processing apparatus 100 is controlled by a controller 221.

[0071] It should be noted that, for example, Figure 5In the substrate processing step of one embodiment of the present application, as shown in (A), a recess 301 in which a silicon (Si) film 302 and a silicon nitride (SiN) film 303 are formed on at least a surface is formed in advance in a wafer 200 processed in the substrate processing step. That is, for the wafer 200 processed in the substrate processing step, the Si film 302 and the SiN film 303 are exposed on the inner side of the recess 301 formed in the wafer 200, and the Si film 302 forms a bottom of the recess 301. The recess 301 is, for example, a trench or a hole, and the aspect ratio of the recess 301 is greater than or equal to 20. In the substrate processing step, for the recess 301, oxidation treatment is performed as a treatment using plasma. The Si film 302 is formed using at least any of single crystal silicon (c-Si), amorphous silicon (a-Si), and polycrystal silicon (Poly-Si).

[0072] (Substrate carrying-in step S110)

[0073] First, the wafer 200 is carried into the processing chamber 201. Specifically, the susceptor lifting mechanism 268 lowers the susceptor 217 to a carrying position of the wafer 200, and the wafer lift pins 266 are inserted through the through-holes 217a of the susceptor 217. As a result, the wafer lift pins 266 are in a state where they protrude from the surface of the susceptor 217 by a prescribed height.

[0074] Next, the gate valve 244 is opened, and the wafer 200 is carried into the processing chamber 201 from a vacuum carrying chamber adjacent to the processing chamber 201 using a wafer carrying mechanism (not shown). The carried-in wafer 200 is supported in a horizontal attitude on the wafer lift pins 266 protruding from the surface of the susceptor 217. After the wafer 200 is carried into the processing chamber 201, the wafer carrying mechanism is retracted outside the processing chamber 201, and the gate valve 244 is closed to seal the processing chamber 201. In addition, the susceptor lifting mechanism 268 raises the susceptor 217, and thus the wafer 200 is supported on the upper surface of the susceptor 217.

[0075] (Warming-up and vacuum exhaust step S120)

[0076] Next, the temperature of the wafer 200 carried into the processing chamber 201 is raised. The heater 217b is preheated, and the wafer 200 is held on the susceptor 217 in which the heater 217b is built, so that the wafer 200 is heated to a prescribed temperature in the range of, for example, 150 to 700°C. Here, the heating is performed in such a manner that the temperature of the wafer 200 becomes 700°C. In addition, during the temperature raising of the wafer 200, the processing chamber 201 is vacuum-exhausted by the vacuum pump 246 via the gas exhaust pipe 231, so that the pressure in the processing chamber 201 becomes a prescribed value. The vacuum pump 246 is operated until at least the end of the substrate carrying-out process S160 described later. Note that the expression of the numerical range such as "150 to 700°C" in this specification means that the lower limit value and the upper limit value are included in the range. Therefore, for example, "150 to 700°C" means "150°C or higher and 700°C or lower". The same applies to other numerical ranges.

[0077] (Process gas supply process S130)

[0078] Next, as the process gas, a mixed gas of the O-containing gas and the H-containing gas is started to be supplied. That is, the mixed gas of the O-containing gas and the H-containing gas as the process gas is supplied into the processing chamber 201 in which the wafer 200 is housed. Specifically, the valves 253a and 253b are opened, and the O-containing gas and the H-containing gas are started to be supplied into the processing chamber 201 while the flow rates are controlled by the MFCs 252a and 252b. At this time, the flow rate of the O-containing gas is made a prescribed value in the range of, for example, 10 to 50,000 seem, preferably 10 to 5,000 seem. In addition, the flow rate of the H-containing gas is set to a prescribed value in the range of, for example, 10 to 50,000 seem, preferably 10 to 5,000 seem.

[0079] The ratio of O to H contained in the mixed gas of the O-containing gas and the H-containing gas as the process gas can be adjusted by controlling the flow rate ratio of the O-containing gas to the H-containing gas. Thus, the ratio of O to H contained in the process gas can be easily controlled. In addition, the ratio of O to H means the ratio of the number of O atoms to the number of H atoms contained in the process gas, and, for example, in the case where a mixed gas of oxygen gas (O2 gas) and hydrogen gas (H2 gas) is used as the mixed gas of the O-containing gas and the H-containing gas, the flow rate ratio of the O-containing gas to the H-containing gas directly becomes the ratio of O to H.

[0080] At this time, the ratio of the thickness of the SiO layer 304b as the second oxide layer formed by oxidizing the surface of the SiN film 303 to the thickness of the SiO layer 304a as the first oxide layer formed by oxidizing the surface of the Si film 302 in the next plasma processing step (S140) is adjusted to a prescribed thickness ratio (for example, to about 0.7) in such a manner that the ratio of O to H contained in the processing gas is adjusted. Note that, in the case of the SiO layer 304b as the second oxide layer formed by oxidizing the surface of the SiN film 303, a Si oxide layer in which nitrogen is contained at a prescribed concentration (i.e., a SiON layer) can be considered.

[0081] For example, by adjusting the ratio of H to O contained in the processing gas in such a manner that the ratio of H to O is increased, the ratio of the thickness of the SiO layer 304b to the thickness of the SiO layer 304a can be decreased.

[0082] In addition, the flow rate ratio of the O-containing gas to the H-containing gas supplied as the processing gas can be adjusted to a value corresponding to the prescribed thickness ratio that is obtained in advance and stored in the storage device 221c or the external storage device 226. In this way, by obtaining in advance and storing in the storage device 221c or the external storage device 226, the operation of adjusting the flow rate ratio of the O-containing gas to the H-containing gas in such a manner that the thickness ratio of the oxide film formed on the Si film 302 and the SiN film 303 becomes the prescribed thickness ratio becomes easy.

[0083] At this time, the opening degree of the APC valve 242 is adjusted to control the exhaust in the processing chamber 201 so that the pressure in the processing chamber 201 becomes a prescribed pressure in the range of, for example, 1 to 250 Pa, preferably 50 to 200 Pa, and more preferably about 150 Pa. In this way, the O-containing gas and the H-containing gas are continuously supplied while the exhaust in the processing chamber 201 is moderately performed until the end of the plasma processing step S140 described later.

[0084] (Plasma processing step S140)

[0085] After the pressure in the processing chamber 201 is stabilized, the high-frequency power is started to be applied to the resonance coil 212 from the high-frequency power source 273 via the RF sensor 272. In the present embodiment, the high-frequency power of 13.54 to 27.12 MHz is supplied from the high-frequency power source 273 to the resonance coil 212. The high-frequency power supplied to the resonance coil 212 is a prescribed power in the range of, for example, 100 to 5000 W, preferably 100 to 3500 W, and more preferably about 3500 W. In the case where the power is lower than 100 W, it is difficult to stably generate plasma discharge.

[0086] Thus, a high-frequency electric field is formed in the plasma generation space 201a to which the O-containing gas and the H-containing gas are supplied, and using this electric field, a doughnut-shaped induced plasma having the highest plasma density is generated at a height position of the plasma generation space corresponding to the electric center point of the resonance coil 212. The O-containing gas and the H-containing gas in the plasma state are dissociated, thereby generating reactive species such as oxygen active species, hydrogen active species, and the like.

[0087] That is, the processing gas, which is a mixed gas of the O-containing gas and the H-containing gas supplied into the processing chamber 201, is plasma-excited to generate reactive species such as oxygen active species and hydrogen active species. Here, by generating reactive species having an oxidizing action such as oxygen active species, and reactive species having an oxidation-inhibiting action such as hydrogen active species, oxidation selectivity to Si films and SiN films can be obtained.

[0088] In addition, by using active species generated by an induced plasma (ICP) having an extremely low potential to perform oxidation, an oxidation layer can be formed with good uniformity on a film formed on the surface of the recess 301 having a high aspect ratio of 20 or more. In addition, even in a case where the recess 301 is formed on a surface formed vertically with respect to the surface direction of the wafer 200, or in a case where the recess 301 is formed non-vertically with respect to the surface direction of the wafer 200, an oxidation layer can be formed with good uniformity with respect to a film formed on the surface thereof.

[0089] At this time, the ratio of the amount of reactive species having an oxidizing action to the amount of reactive species having an oxidation-inhibiting action generated by plasma excitation is adjusted so as to correspond to the ratio of the thickness of the prescribed oxidation layer. For example, by controlling the ratio of oxygen active species (more specifically, for example, O radicals) as reactive species having an oxidizing action, and hydrogen active species (more specifically, for example, H radicals) as reactive species having an oxidation-inhibiting action, the ratio of the thickness of the SiO layer 304b with respect to the SiO layer 304a can be adjusted.

[0090] Further, by supplying reactive species having an oxidizing action such as oxygen active species, and reactive species having an oxidation-inhibiting action such as hydrogen active species to the wafer 200, the surfaces of the Si film 302 and the SiN film 303 formed in the recess 301 on the wafer 200 so as to be exposed, respectively, are oxidized, and the SiO layer 304a and the SiO layer 304b are formed, respectively. That is, as shown in FIG. 4, the SiO layer 304a and the SiO layer 304b are formed in the recess 301 on the wafer 200. Figure 5As shown in (B), a uniformly thick SiO layer 304a is formed on the entire exposed surface of the Si film 302 constituting the bottom of the recess 301, and a uniformly thick SiO layer 304b is formed on the entire exposed surface of the SiN layer 303 constituting the sidewall of the recess 301. Furthermore, a thicker SiO layer 304a is formed on the exposed surface of the Si film 302 constituting the bottom of the recess 301 compared to the SiO layer 304b formed on the exposed surface of the SiN film 303. That is, the surface of the Si film 304 can be selectively oxidized relative to the surface of the SiN film 303 to form the SiO layer 304a as an oxide layer.

[0091] Based on the research of the inventors of this application, such as Figure 5 As shown in (A), when plasma excitation is performed on wafer 200 using O2 gas containing only oxygen as the processing gas to perform oxidation treatment, a selectivity of approximately 93% (ratio of the thickness of the oxide layer formed on the Si film to the thickness of the oxide layer formed on the SiN film) can only be obtained, exceeding 90%. In contrast, according to the inventors' research, by using a mixture of O and H gases (i.e., a mixture of O2 and H2 gases) as the processing gas and adjusting the ratio of O to H in the mixture, it was confirmed that the ratio of the thickness of the oxide layer formed on the Si film to the thickness of the oxide layer formed on the SiN film can be set to 90% or less. That is, it was confirmed that it is possible to control the ratio of the thickness of the oxide layer on the SiN film to the thickness of the oxide layer on the Si film when using a mixture of O and H gases as the processing gas to be a smaller value than when using only O2 gas as the processing gas.

[0092] In other words, compared to using only O2 gas as the processing gas, using a mixture of O and H gases as the processing gas and adjusting the ratio of O to H in the processing gas allows control over the ratio of the oxide layer thickness on the SiN film to the oxide layer thickness on the Si film. That is, the selectivity of the oxide layer thickness formed on the Si and SiN films can be controlled.

[0093] Specifically, the ratio of the number of H atoms to the total of the number of O atoms and the number of H atoms contained in the processing gas is adjusted to be 5% or more, whereby the ratio of the thickness of the SiO layer 304b to the thickness of the SiO layer 304a can be made to be 90% or less. Further, the ratio of the O-containing gas to the H-containing gas contained in the processing gas is adjusted in such a manner that the ratio of the number of H atoms to the total of the number of O atoms and the number of H atoms contained in the processing gas is 10% or more, whereby the ratio of the thickness of the SiO layer 304b to the thickness of the SiO layer 304a can be made to be 80% or less. Further, the ratio of the O-containing gas to the H-containing gas contained in the processing gas is adjusted in such a manner that the ratio of the number of H atoms to the total of the number of O atoms and the number of H atoms contained in the processing gas is 20% or more, whereby the ratio of the thickness of the SiO layer 304b to the thickness of the SiO layer 304a can be made to be 70% or less.

[0094] Note that in a case where the ratio of the number of H atoms contained in the processing gas is made to exceed 80%, for example, a practical oxidation rate with respect to the Si film cannot be obtained. With respect to the ratio of the O-containing gas to the H-containing gas contained in the processing gas, by setting it to a value such that the ratio of the number of H atoms to the total of the number of O atoms and the number of H atoms contained in the processing gas is 80% or less, the selectivity of the thickness of the oxidation layer can be obtained while maintaining a practical oxidation rate with respect to the Si film. Note that in a case where a mixed gas of O2 gas and H2 gas is used as the processing gas, the ratio of the number of O atoms to the number of H atoms contained in the processing gas is directly set to the ratio of the supply amounts of the O2 gas and the H2 gas.

[0095] After a prescribed processing time, for example, 10 to 300 seconds elapses, the output of electric power from the high-frequency power source 273 is stopped, and the plasma discharge in the processing chamber 201 is stopped. Further, the valves 253a and 253b are closed, and the supply of the O-containing gas and the H-containing gas into the processing chamber 201 is stopped. With the above operation, the plasma processing step S140 is ended.

[0096] (Vacuum Exhaust Step S150)

[0097] After the supply of the O-containing gas and the H-containing gas is stopped, the inside of the processing chamber 201 is vacuum-exhausted via the gas exhaust pipe 231. Thus, the O-containing gas, the H-containing gas, exhaust gas generated by the reaction of these gases, and the like in the processing chamber 201 are exhausted to the outside of the processing chamber 201. Thereafter, the opening degree of the APC valve 242 is adjusted, and the pressure in the processing chamber 201 is adjusted to be the same as the pressure in a vacuum transfer chamber (a wafer 200 unillustrated is carried out to) adjacent to the processing chamber 201.

[0098] (Substrate unloading step S160)

[0099] After the prescribed pressure is reached in the processing chamber 201, the susceptor 217 is lowered to a wafer 200 unloading position, and the wafer 200 is supported on the wafer elevation pins 266. In addition, the gate valve 244 is opened, and the wafer 200 is unloaded outside the processing chamber 201 using a wafer unloading mechanism. With the above operation, the substrate processing step according to the present embodiment is completed.

[0100] As the O-containing gas, for example, an O2 gas, an ozone (O3) gas, a water vapor (H2O gas), a hydrogen peroxide (H2O2) gas, a nitric oxide (NO) gas, a dinitrogen oxide (N2O) gas, or the like can be used. In addition, as the O-containing gas, a gas containing at least any one of the above can be used.

[0101] In addition, as the H-containing gas, for example, an H2 gas, an H2O gas, an H2O2 gas, a deuterium (D2) gas, or the like can be used. In addition, as the H-containing gas, a gas containing at least any one of the above can be used.

[0102] Note that, for the O-containing gas and the H-containing gas, different gases from each other are used. For example, for the O-containing gas and the H-containing gas, gases different from each other in the ratio of the number of O atoms to the number of H atoms contained in each unit flow rate of the respective gases are used. In addition, for the O-containing gas and the H-containing gas, gases different from each other in the ratio of the number of O atoms to the number of H atoms contained in the composition (molecular structure) of the respective gases are used.

[0103] (4) Other Embodiments

[0104] [2nd Embodiment]

[0105] Next, the 2nd embodiment of the present application will be described using Figure 6 Here, the description will be mainly given to the aspects different from the above 1st embodiment, and the description will be omitted for other aspects. In the 2nd embodiment, the configuration of the substrate processing apparatus is different from that of the 1st embodiment. The other aspects are the same as those of the 1st embodiment. In the 2nd embodiment, the description will be given to the configuration of the substrate processing apparatus.

[0106] The substrate processing apparatus 400 is provided with a processing furnace 402 that performs plasma processing on the wafer 200. In the processing furnace 402, a processing container 403 that constitutes the processing chamber 401 is provided.

[0107] In the center of the bottom side of the processing chamber 401, a susceptor 217 is provided as a substrate mounting portion on which the wafer 200 is mounted. Inside the susceptor 217, a heater 217b is integrally built as a heating mechanism. The heater 217b is configured to heat the surface of the wafer 200, for example, from 25°C to about 750°C, when power is supplied thereto.

[0108] On the susceptor 217, a susceptor lift mechanism 268 is provided, which has a drive mechanism that lifts the susceptor.

[0109] Above the processing chamber 401, a gas introduction port 434a and a gas introduction port 434b are provided.

[0110] On the gas introduction port 434a, a downstream end of a supply pipe 406a that supplies an oxygen active species or the like, which is a reaction species having an oxidizing action, into the processing chamber 401 is connected. On an upstream end of the supply pipe 406a, a first plasma excitation chamber 404a is connected. On the first plasma excitation chamber 404a, a downstream end of an oxygen-containing gas supply pipe 232a that supplies an oxygen-containing gas is connected. On the oxygen-containing gas supply pipe 232a, an oxygen-containing gas supply source 250a, an MFC 252a, and a valve 253a are provided in this order from the upstream side. On the first plasma excitation chamber 404a, a high-frequency power source 273a is connected.

[0111] On the gas introduction port 434b, a downstream end of a supply pipe 406b that supplies a hydrogen active species or the like, which is a reaction species having an oxidation-inhibiting action, into the processing chamber 401 is connected. On an upstream end of the supply pipe 406b, a second plasma excitation chamber 404b is connected. On the second plasma excitation chamber 404b, a downstream end of a hydrogen-containing gas supply pipe 232b that supplies a hydrogen-containing gas is connected. On the hydrogen-containing gas supply pipe 232b, a hydrogen-containing gas supply source 250b, an MFC 252b, and a valve 253b are provided in this order from the upstream side. On the second plasma excitation chamber 404b, a high-frequency power source 273b is connected.

[0112] Note that, on the first plasma excitation chamber 404a and the second plasma excitation chamber 404b, for example, a coil to which high-frequency power is supplied from the high-frequency power source 273a or the high-frequency power source 273b is wound, respectively, and the gas introduced into the first plasma excitation chamber 404a and the second plasma excitation chamber 404b is plasma-excited by the electromagnetic field generated by the coil. Thus, the oxygen-containing gas introduced into the first plasma excitation chamber 404a is plasma-excited to generate an oxygen active species therefrom, and the hydrogen-containing gas introduced into the second plasma excitation chamber 404b is plasma-excited to generate a hydrogen active species therefrom. Note that the plasma excitation means of the gas is not limited to the coil, and other plasma excitation means such as a microwave supply device can also be used.

[0113] The oxygen-containing gas supply system according to the present embodiment is mainly composed of the oxygen-containing gas supply pipe 232a, the MFC 252a, the valve 253a, the first plasma excitation chamber 404a, and the supply pipe 406a. The hydrogen-containing gas supply system according to the present embodiment is mainly composed of the hydrogen-containing gas supply pipe 232b, the MFC 252b, the valve 253b, the second plasma excitation chamber 404b, and the supply pipe 406b. In addition, the processing gas supply system is composed of the oxygen-containing gas supply system and the hydrogen-containing gas supply system.

[0114] In the first plasma excitation chamber 404a, the O-containing gas supplied from the oxygen-containing gas supply pipe 232a is plasma-excited to generate oxygen active species. In addition, in the second plasma excitation chamber 404b, the H-containing gas supplied from the hydrogen-containing gas supply pipe 232b is plasma-excited to generate hydrogen active species. The first plasma excitation chamber 404a and the second plasma excitation chamber 404b are mainly used to configure the plasma generation section (plasma generation mechanism) according to the present embodiment. Note that, as the plasma generation section, the high-frequency power sources 273a and 273b can also be included.

[0115] That is, the valves 253a and 253b are opened, respectively, and the flow rates of the gases are adjusted by the MFCs 252a and 252b, respectively, and the gases are supplied to the first plasma excitation chamber 404a and the second plasma excitation chamber 404b, respectively. Furthermore, the oxygen active species and the hydrogen active species are supplied to the processing chamber 401 via the supply pipes 406a and 406b by plasma-exciting the respective gases in the first plasma excitation chamber 404a and the second plasma excitation chamber 404b.

[0116] That is, the oxygen active species and the hydrogen active species supplied from the gas introduction ports 434a and 434b into the processing chamber 401 are supplied to the wafer 200, and the SiO layer 304a and the SiO layer 304b having a predetermined film thickness ratio are formed in the recessed portion 301 in which the Si film 302 and the SiN film 303 are exposed as shown in (A) of FIG. 6, and the SiO layer 304a and the SiO layer 304b are formed as shown in (B) of FIG. 6. Figure 5 Figure 5

[0117] ​​According to the substrate processing apparatus 400, the supply amounts of the oxygen active species and the hydrogen active species can be controlled individually. That is, the ratio of the amount of the oxygen active species generated in the first plasma generation chamber 404a to the amount of the hydrogen active species generated in the second plasma generation chamber 404b can be adjusted so as to become a ratio of active species corresponding to a prescribed thickness ratio of the oxidation layer. That is, by controlling the ratio of the amounts of the oxygen active species and the hydrogen active species supplied to the wafer 200, the thickness ratio of the SiO layer 304b with respect to the SiO layer 304a can be adjusted. Note that the ratio of the amounts of the oxygen active species and the hydrogen active species supplied to the wafer 200 is adjusted by controlling at least one of the flow rate ratio of the O-containing gas supplied to the first plasma generation chamber 404a to the H-containing gas supplied to the second plasma generation chamber 404b or the power ratio of the high-frequency power for exciting the O-containing gas supplied to the first plasma generation chamber 404a to the high-frequency power for exciting the H-containing gas supplied to the second plasma generation chamber 404b.

[0118] That is, by controlling the flow rate ratio of the O-containing gas and the H-containing gas by controlling the MFCs 252a and 252b individually or by controlling the power ratio of the high-frequency power applied to the first plasma generation chamber and the second plasma generation chamber by controlling the high-frequency power sources 273a and 273b individually, the amounts of the oxygen active species and the hydrogen active species supplied to the wafer 200 in the processing chamber 401 can be adjusted individually. That is, by adjusting the ratio of the amounts of the oxygen active species and the hydrogen active species supplied to the wafer 200, the ratio of the thickness of the SiO layer 304b formed by oxidizing the surface of the SiN film 303 with respect to the thickness of the SiO layer 304a formed by oxidizing the surface of the Si film 302 can be adjusted to a prescribed thickness ratio. Note that the ratio of the supply amounts of the oxygen active species and the hydrogen active species can also be achieved by adjusting the ratio between the specific kinds of the oxygen active species and the hydrogen active species (the ratio of the supply amounts of O radicals and H radicals, etc.).

[0119] In the case of using the above-described substrate processing apparatus 400, the film can be formed by the same substrate processing procedure and processing conditions as those of the above-described first embodiment, and the same effects as those of the above-described first embodiment can be obtained. That is, in the case of using the substrate processing apparatus 400, the oxidation layer can also be selectively and uniformly formed on the exposed surface of the Si film constituting the bottom of the recess in which the Si film and the SiN film are exposed.

[0120] As the O-containing gas and the H-containing gas, the same gases as those of the O-containing gas and the H-containing gas in the above-described first embodiment can be used. In addition, the same as in the first embodiment, different gases can be used as the O-containing gas and the H-containing gas.

[0121] Note that in the second embodiment, a gas not containing H (e.g., O2 gas, O3 gas, NO gas, N2O gas, or the like) can be used as the O-containing gas, and a gas not containing O (e.g., H2 gas, D2 gas, or the like) can be used as the H-containing gas. By being provided as such a combination of the O-containing gas and the H-containing gas, it is possible to more easily adjust the ratio of the amounts of the oxygen active species and the hydrogen active species supplied from the oxygen-containing gas supply system and the hydrogen-containing gas supply system, using at least either the control of the flow rate ratio of the O-containing gas and the H-containing gas or the control of the high-frequency power sources 273a and 273b.

[0122] The above describes various typical embodiments of the present application, but the present application is not limited to the above-described embodiments and can be used in appropriate combinations.

[0123] Example 1

[0124] Using Figure 1 the substrate processing apparatus shown in Figure 4 the substrate processing sequence shown in FIG. 6, the ratio of H with respect to the total of O and H contained in the mixed gas of the O-containing gas and the H-containing gas as the processing gas was changed from 5% to 20%, and the Si film and the SiN film formed on the wafer were oxidized. Then, the ratio of the thickness of the oxide film formed on the SiN film with respect to the thickness of the oxide layer formed on the Si film (oxidation selectivity) was evaluated.

[0125] As Figure 7 shown in FIG. 7, when the ratio of H with respect to the total of O and H contained in the mixed gas as the processing gas was set to 5%, the oxidation ratio of the SiN film with respect to the Si film, i.e., the oxidation selectivity was 87%. Thus, it was confirmed that by adjusting the ratio of H with respect to the total of O and H contained in the mixed gas to 5% or more, the oxidation selectivity can be adjusted to 90% or less.

[0126] In addition, when the ratio of H with respect to the total of O and H contained in the mixed gas as the processing gas was set to 10%, the oxidation selectivity of the SiN film with respect to the Si film was 77%. Thus, it was confirmed that by adjusting the ratio of H with respect to the total of O and H contained in the mixed gas to 10% or more, the oxidation selectivity can be adjusted to 80% or less.

[0127] Furthermore, when the ratio of H relative to the total O and H contained in the mixed gas used as the processing gas is set to 20%, the oxidation selectivity of the SiN film relative to the Si film is 67%. Therefore, it has been confirmed that by adjusting the ratio of H relative to the total O and H contained in the mixed gas to 20% or more, the oxidation selectivity can be adjusted to 70% or less.

[0128] Furthermore, when the ratio of H to the total O and H contained in the mixed gas containing O and H is greater than 20%, it is speculated that the oxidation selectivity of the SiN film relative to the Si film will further decrease. In other words, by adjusting the ratio to increase the ratio of H to the total O and H contained in the process gas, it was confirmed that the oxidation selectivity of the SiN film relative to the Si film can be reduced, and the oxidation selectivity can be improved.

[0129] It should be noted that the use Figure 1 The substrate processing apparatus shown is in Figure 4 In the substrate processing steps shown, for two experimental examples with different magnitudes of high-frequency electric current for exciting the mixed gas, the ratio of oxide film thickness formed on the Si film and on the SiN film of the wafer was evaluated. Under all conditions, the oxidation selectivity was approximately 0.87, and oxidation selectivity was not confirmed. Additionally, using... Figure 1 The substrate processing apparatus shown is in Figure 4 In the substrate processing steps shown, for two experimental examples with different pressures within the processing chamber, the ratio of oxide film thickness formed on the Si film and on the SiN film of the wafer was evaluated. In both cases, the oxidation selectivity was approximately 0.87, and no oxidation selectivity was confirmed. Additionally, using... Figure 1 The substrate processing apparatus shown is in Figure 4 In the substrate processing steps shown, for two experimental examples with different wafer temperatures, the ratio of oxide film thickness formed on the Si film and on the SiN film of the wafer was evaluated. The oxidation selectivity ratios were 0.87 and 0.88, respectively, showing a slight difference, and oxidation selectivity was not confirmed. Additionally, using... Figure 1 The substrate processing apparatus shown is in Figure 4 In the substrate processing steps shown, for two experimental examples with different wafer heights relative to the plasma source, the ratio of the thickness of the oxide film formed on the Si film and the SiN film on the wafer was evaluated. In both cases, the oxidation selectivity was about 0.87, and no oxidation selectivity was confirmed.

Claims

1. A method for manufacturing a semiconductor device, comprising the steps of: (a) a step of generating reactive species by plasma-exciting a processing gas containing oxygen and hydrogen; and (b) a step of supplying the reactive species to a substrate to oxidize surfaces of a silicon film and a silicon nitride film respectively formed on the substrate, the ratio of oxygen to hydrogen contained in the processing gas being adjusted in such a manner that the ratio of hydrogen to the total of oxygen and hydrogen contained in the processing gas is 5% or more and 20% or less, and the ratio of the thickness of a second oxide layer formed by oxidizing the surface of the silicon nitride film in (b) to the thickness of a first oxide layer formed by oxidizing the surface of the silicon film is a prescribed thickness ratio of 67% or more and 90% or less. (c) a step of adjusting the ratio of oxygen to hydrogen contained in the processing gas in such a manner that the ratio of the thickness of the second oxide layer to the thickness of the first oxide layer is the prescribed thickness ratio. In (c), the ratio of hydrogen to oxygen contained in the processing gas is adjusted in such a manner that the ratio of the thickness of the second oxide layer to the thickness of the first oxide layer becomes smaller. wherein The ratio of oxygen to hydrogen contained in the processing gas is adjusted to a value corresponding to the prescribed thickness ratio that is obtained in advance.

2. The method of manufacturing a semiconductor device according to Claim 1, further comprising: In (a), at least an oxygen active species and a hydrogen active species are generated as the reactive species.

3. The method for manufacturing a semiconductor device according to Claim 2, wherein The ratio of oxygen to hydrogen contained in the processing gas is adjusted in such a manner that the ratio of the amount of the oxygen active species to the amount of the hydrogen active species supplied to the substrate in (b) is an active species ratio corresponding to the prescribed thickness ratio.

4. The method for manufacturing a semiconductor device according to Claim 1, wherein 7. The method for manufacturing a semiconductor device according to claim 1, the prescribed thickness ratio being a smaller value than the ratio of the thickness of the second oxide layer to the thickness of the first oxide layer in a case where a gas containing only oxygen is used as the processing gas in (a) and (b).

5. The method for manufacturing a semiconductor device according to Claim 1, wherein The ratio of oxygen to hydrogen contained in the processing gas is adjusted in such a manner that the ratio of the thickness of the second oxide layer to the thickness of the first oxide layer is 80% or less.

6. The method for manufacturing a semiconductor device according to Claim 5, wherein The ratio of oxygen to hydrogen contained in the processing gas is adjusted in such a manner that the ratio of hydrogen to the total of oxygen and hydrogen contained in the processing gas is 10% or more. The ratio of oxygen to hydrogen contained in the processing gas is adjusted in such a manner that the ratio of the thickness of the second oxide layer to the thickness of the first oxide layer is 70% or less.

8. The method for manufacturing a semiconductor device according to Claim 1, wherein The processing gas is a mixed gas of an oxygen-containing gas and a hydrogen-containing gas.

9. The method of manufacturing a semiconductor device according to Claim 1, wherein The oxygen-containing gas is an oxygen gas, and the hydrogen-containing gas is a hydrogen gas.

10. The method of manufacturing a semiconductor device according to Claim 1, wherein The ratio of oxygen to hydrogen contained in the processing gas is adjusted by controlling the flow rate ratio of the oxygen-containing gas to the hydrogen-containing gas.

11. The method of manufacturing a semiconductor device according to Claim 1, wherein The silicon film is composed of at least any one of single crystal silicon, amorphous silicon, and polycrystal silicon.

12. The method of manufacturing a semiconductor device according to Claim 11, wherein ​ 13. The method of manufacturing a semiconductor device according to Claim 11 or 12, wherein ​ 14. The method of manufacturing a semiconductor device according to Claim 1, wherein ​ 15. The method of manufacturing a semiconductor device according to Claim 1, wherein The silicon film and the silicon nitride film are exposed on the inner side of a recess formed in the substrate, the recess has an aspect ratio of 20 or more, the silicon film constitutes a bottom of the recess, (b) in which a uniform thickness of the first oxide layer is formed on the entire exposed surface of the silicon film constituting the bottom of the recess.

16. The method of manufacturing a semiconductor device according to Claim 1, wherein (a) in which the processing gas is supplied into a processing chamber in which the substrate is accommodated, and the processing gas supplied into the processing chamber is plasma-excited by supplying high-frequency power to a resonance coil provided in a manner of surrounding the outer periphery of the processing chamber.

17. A substrate processing method comprising the following steps: (a) a step of generating reaction species by plasma-exciting a processing gas containing oxygen and hydrogen; and (b) a step of oxidizing surfaces of a silicon film and a silicon nitride film respectively exposed on a substrate by supplying the reaction species to the substrate, wherein the ratio of oxygen to hydrogen contained in the processing gas is adjusted in such a manner that the ratio of hydrogen contained in the processing gas to the total of oxygen and hydrogen is 5% or more and 20% or less, and the ratio of the thickness of a second oxide layer formed by oxidizing the surface of the silicon nitride film in (b) to the thickness of a first oxide layer formed by oxidizing the surface of the silicon film is a prescribed thickness ratio of 67% or more and 90% or less.

18. A computer-readable recording medium recording a program for causing a substrate processing apparatus to execute the following steps by using a computer: (a) a step of generating reaction species by plasma-exciting a processing gas containing oxygen and hydrogen; and (b) a step of oxidizing surfaces of a silicon film and a silicon nitride film respectively exposed on a substrate by supplying the reaction species to the substrate, and a step of adjusting the ratio of oxygen to hydrogen contained in the processing gas in such a manner that the ratio of hydrogen contained in the processing gas to the total of oxygen and hydrogen is 5% or more and 20% or less, and the ratio of the thickness of a second oxide layer formed by oxidizing the surface of the silicon nitride film in (b) to the thickness of a first oxide layer formed by oxidizing the surface of the silicon film is a prescribed thickness ratio of 67% or more and 90% or less.

19. A substrate processing apparatus comprising: a processing chamber in which a substrate is accommodated; a processing gas supply system that supplies a processing gas containing oxygen and hydrogen into the processing chamber; a plasma generation mechanism that plasma-excites the processing gas supplied into the processing chamber; and a control section configured to control the processing gas supply system and the plasma generation mechanism in a manner capable of performing each of the steps in claim 1 in the processing chamber.

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