Substrate processing method, method for manufacturing semiconductor device, program and substrate processing apparatus

Abstract

To provide a technology that makes it possible to control changes in etching resistance that occur near the interface with a substrate when forming a film on the substrate.SOLUTION: It has (a) a step for forming an intermediate layer containing carbon on a first film formed on a substrate; and (b) a step for forming a second film containing nitrogen on the intermediate layer using an activated nitrogen-containing gas, and in the step (a) the intermediate layer is formed so that the carbon content per unit area in the intermediate layer differs between the central region in the substrate plane and the outer region thereof.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a substrate processing method, a semiconductor device manufacturing method, a program, and a substrate processing apparatus. [Background technology]

[0002] 2. Description of the Related Art As one step in the manufacturing process of a semiconductor device, a process of supplying a process gas to a substrate to form a film on the substrate is performed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 199111 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a film is formed, characteristics such as etching resistance may change near the interface between the underlayer and the film. It may be necessary to suppress the occurrence of such changes in characteristics, or, even if a layer with changed characteristics (hereinafter referred to as a "transition layer") is formed, to control the distribution of the thickness of the layer within the surface of the substrate.

[0005] The present disclosure provides a technology that can suppress changes in properties such as etching resistance that occur near the interface between the base and the film when forming a film, or that can control the distribution of thickness of a transition layer within the surface of a substrate even when a transition layer is formed. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, (a) forming an intermediate layer containing carbon on a first film formed on a substrate; (b) forming a second film containing nitrogen on the intermediate layer using an activated nitrogen-containing gas; In the step (a), the intermediate layer is formed so that the carbon content per unit area contained in the intermediate layer differs between a central region and an outer region within the substrate surface. Technology is provided. Effect of the Invention

[0007] According to the present disclosure, when forming a film, it is possible to suppress changes in properties such as etching resistance that occur near the interface between the base and the film, or, even if a transition layer is formed, it is possible to control the distribution of the thickness of the transition layer within the surface of the substrate. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus suitably used in one embodiment of the present disclosure, showing a processing furnace portion in vertical cross section. [Diagram 2] FIG. 2 is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus suitably used in one embodiment of the present disclosure, showing a processing furnace portion in a cross-sectional view taken along line AA in FIG. [Diagram 3] FIG. 3 is a schematic configuration diagram of a controller of a substrate processing apparatus suitably used in one embodiment of the present disclosure, and is a block diagram showing a control system of the controller. [Figure 4] FIG. 4 is a flow diagram showing a substrate processing process suitably used in one embodiment of the present disclosure. [Diagram 5] 5(A) and 5(B) are diagrams showing an example of a cross-sectional structure of a film formed on a substrate. [Figure 6] 6(A) and 6(B) are diagrams showing the cross-sectional structure of a film formed on a substrate according to a modified example. [Figure 7] FIG. 7 is a diagram showing the results of evaluation of the etching resistance of a film formed on a substrate. [Figure 8]FIG. 8 is a diagram showing the results of evaluation of the etching resistance of a central region and an outer region within the surface of a film formed on a substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <One aspect of the present disclosure> Hereinafter, one embodiment of the present disclosure will be described mainly with reference to Figures 1 to 5. Note that all of the drawings used in the following description are schematic, and the dimensional relationships of the elements, the ratios of the elements, etc. shown in the drawings do not necessarily match the actual ones. Furthermore, the dimensional relationships of the elements, the ratios of the elements, etc. between multiple drawings do not necessarily match.

[0010] (1) Configuration of the substrate processing device 1, the process furnace 202 has a heater 207 as a heating mechanism (temperature adjustment unit). The heater 207 also functions as an activation mechanism (excitation unit) that activates (excites) gas by heat, as described later.

[0011] A reaction tube 203 constituting a reaction vessel (processing vessel) is disposed inside the heater 207 concentrically with the heater 207. The reaction tube 203 is formed in a cylindrical shape with a closed upper end and an open lower end. A processing chamber 201 is formed in a cylindrical hollow portion of the reaction tube 203. The processing chamber 201 is configured to be capable of accommodating wafers 200 as substrates in a horizontal position and aligned vertically in multiple stages using a boat 217 described later.

[0012] Nozzles 249a and 249b are provided in the processing chamber 201 so as to penetrate the lower part of the reaction tube 203. Gas supply pipes 232a and 232b are connected to the nozzles 249a and 249b, respectively. Gas supply pipe 232c is connected to the gas supply pipe 232b. In this manner, the reaction tube 203 is provided with two nozzles 249a and 249b and three gas supply pipes 232a to 232c, and is configured to be able to supply a plurality of types of gases into the processing chamber 201.

[0013] Gas supply pipes 232a-232c are provided with mass flow controllers (MFCs) 241a-241c, which are flow rate controllers (flow rate control parts), and valves 243a-243c, which are on-off valves, in order from the upstream direction. Gas supply pipe 232d, which supplies an inert gas, is connected to the downstream side of valve 243a of gas supply pipe 232a. Gas supply pipe 232e, which supplies an inert gas, is connected to the downstream side of the connection part of gas supply pipe 232b with gas supply pipe 232c. Gas supply pipes 232d and 232e are provided with MFCs 241d and 241e and valves 243d and 243e, respectively, in order from the upstream direction.

[0014] A nozzle 249a is connected to the tip of the gas supply pipe 232a. As shown in FIG. 2, the nozzle 249a is provided in a circular space between the inner wall of the reaction tube 203 and the wafers 200 in a plan view, along the inner wall of the reaction tube 203 from the lower part to the upper part, so as to rise upward in the loading direction of the wafers 200. A gas supply hole 250a for supplying gas is provided on the side of the nozzle 249a. The gas supply hole 250a opens toward the center of the reaction tube 203, and can supply gas toward the wafers 200. A plurality of gas supply holes 250a are provided from the lower part to the upper part of the reaction tube 203, each having the same opening area, and further provided at the same opening pitch.

[0015] A nozzle 249b is connected to the tip of the gas supply pipe 232b. The nozzle 249b is provided in a buffer chamber 237, which is a gas dispersion space. The buffer chamber 237 is formed between the inner wall of the reaction tube 203 and a partition wall 237a. As shown in FIG. 2, the buffer chamber 237 (partition wall 237a) is provided in a space having an annular shape in a plan view between the inner wall of the reaction tube 203 and the wafer 200, and in a portion extending from the lower part to the upper part of the inner wall of the reaction tube 203 along the loading direction of the wafer 200. A gas supply hole 250c for supplying gas is provided at an end of the surface of the partition wall 237a facing (adjacent to) the wafer 200. The gas supply hole 250c is opened to face the center of the reaction tube 203, and is capable of supplying gas toward the wafer 200. A plurality of gas supply holes 250c are provided from the lower part to the upper part of the reaction tube 203, each having the same opening area, and further provided at the same opening pitch.

[0016] The nozzle 249b is provided at the end of the buffer chamber 237 opposite to the end where the gas supply holes 250c are provided, along the inner wall of the reaction tube 203 from the lower part to the upper part, so as to rise upward in the stacking direction of the wafers 200. Gas supply holes 250b for supplying gas are provided on the side of the nozzle 249b. The gas supply holes 250b open toward the center of the buffer chamber 237. Similar to the gas supply holes 250c, a plurality of gas supply holes 250b are provided from the lower part to the upper part of the reaction tube 203. The gas ejected from the gas supply holes 250b into the buffer chamber 237 is ejected into the processing chamber 201 from the gas supply holes 250c.

[0017] In this manner, in this embodiment, the gas is transported via the nozzles 249a, 249b and the buffer chamber 237 arranged in the cylindrical space. Then, the gas is ejected into the reaction tube 203 from the gas supply holes 250a-250c in the vicinity of the wafer 200 for the first time. Then, the main flow of the gas in the reaction tube 203 is parallel to the surface of the wafer 200, that is, horizontal. The gas that has flowed over the surface of the wafer 200, that is, the remaining gas after the reaction, flows toward the exhaust port, that is, toward the exhaust pipe 231 described later.

[0018] From the gas supply pipe 232a, a source gas containing a predetermined element, for example, a source gas containing silicon (Si) and a halogen element as the predetermined element, is supplied into the processing chamber 201 via the MFC 241a and the valve 243a.

[0019] A nitrogen (N)-containing gas serving as a nitriding gas is supplied from the gas supply pipe 232b into the processing chamber 201 via the MFC 241b and the valve 243b.

[0020] As the nitriding gas, an N-containing gas activated by plasma excitation can be used. Alternatively, as the nitriding gas, an N-containing gas activated by thermal excitation without using plasma excitation (i.e., non-plasma excitation) can be used.

[0021] A gas containing carbon (C) and nitrogen (N) is supplied from the gas supply pipe 232c through the MFC 241c and the valve 243c into the processing chamber 201. The gas containing C and N can also be regarded as a C-containing gas.

[0022] Inert gas is supplied from the gas supply pipes 232d and 232e into the processing chamber 201 via the MFCs 241d and 241e and the valves 243d and 243e, respectively.

[0023] The gas supply pipe 232a, the MFC 241a, and the valve 243a mainly constitute a source gas supply system. The nozzle 249a may be included in the source gas supply system. The source gas supply system may also be referred to as a source supply system.

[0024] Furthermore, the N-containing gas supply system is mainly composed of the gas supply pipe 232b, the MFC 241b, and the valve 243b. The N-containing gas supply system may include the nozzle 249b and the buffer chamber 237. The N-containing gas supply system may also be called a nitriding gas supply system or a nitriding agent supply system.

[0025] Furthermore, a C- and N-containing gas supply system is mainly composed of the gas supply pipe 232c, the MFC 241c, and the valve 243c. The downstream side of the connection part between the gas supply pipe 232b and the gas supply pipe 232c, the nozzle 249b, and the buffer chamber 237 may be included in the C- and N-containing gas supply system. The C- and N-containing gas supply system may also be regarded as a C-containing gas supply system.

[0026] Any or all of the above-mentioned raw material gas, N-containing gas, and C and N-containing gas can be referred to as a processing gas. Any or all of the raw material gas supply system, N-containing gas supply system, and C and N-containing gas supply system can be referred to as a processing gas supply system, or simply as a supply system.

[0027] Furthermore, an inert gas supply system is mainly composed of the gas supply pipes 232d and 232e, the MFCs 241d and 241e, and the valves 243d and 243e. The inert gas supply system may also be called a purge gas supply system or a carrier gas supply system.

[0028] As shown in FIG. 2, in the buffer chamber 237, two rod-shaped electrodes 269, 270 made of a conductor and having an elongated structure are arranged from the lower part to the upper part of the reaction tube 203 along the arrangement direction of the wafers 200. Each of the rod-shaped electrodes 269, 270 is provided in parallel with the nozzle 249b. Each of the rod-shaped electrodes 269, 270 is protected by being covered from the upper part to the lower part by an electrode protection tube 275. One of the rod-shaped electrodes 269, 270 is connected to a high-frequency power source 273 via a matching unit 272, and the other is connected to earth, which is a reference potential. By applying high-frequency (RF) power from the high-frequency power source 273 between the rod-shaped electrodes 269, 270, plasma is generated in the plasma generation region 224 between the rod-shaped electrodes 269, 270. The rod-shaped electrodes 269, 270 and the electrode protection tube 275 mainly constitute a plasma source as a plasma generator (plasma generating unit). The plasma source may include the matching box 272 and the high frequency power supply 273. As described below, the plasma source functions as a plasma excitation unit (activation mechanism) that excites a gas into a plasma state, that is, excites (activates) the gas into a plasma state.

[0029] The reaction tube 203 is provided with an exhaust pipe 231 for exhausting the atmosphere in the processing chamber 201. A vacuum pump 246 as a vacuum exhaust device is connected to the exhaust pipe 231 via a pressure sensor 245 as a pressure detector (pressure detection unit) for detecting the pressure in the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 as a pressure regulator (pressure adjustment unit). The APC valve 244 is a valve configured to be able to perform evacuation and stop evacuation in the processing chamber 201 by opening and closing the valve while the vacuum pump 246 is in operation, and further, to adjust the pressure in the processing chamber 201 by adjusting the valve opening based on pressure information detected by the pressure sensor 245 while the vacuum pump 246 is in operation. An exhaust system is mainly configured by the exhaust pipe 231, the APC valve 244, and the pressure sensor 245. The vacuum pump 246 may be included in the exhaust system.

[0030] A seal cap 219 is provided below the reaction tube 203 as a furnace port cover capable of airtightly closing the lower end opening of the reaction tube 203. A rotation mechanism 267 for rotating a boat 217, which will be described later, is provided on the opposite side of the seal cap 219 from the processing chamber 201. A rotation shaft 255 of the rotation mechanism 267 is connected to the boat 217, and is configured to rotate the wafers 200 by rotating the boat 217. A boat elevator 115 as a lifting mechanism vertically installed outside the reaction tube 203 is configured to lift and lower the seal cap 219 to load and unload the boat 217 into and out of the processing chamber 201.

[0031] The boat 217 as a substrate support is configured to support a plurality of wafers 200, for example 25 to 200, in multiple stages in a horizontal position and aligned vertically with their centers aligned, i.e., arranged at intervals. At the bottom of the boat 217, heat insulating plates 218 are supported in multiple stages in a horizontal position.

[0032] A temperature sensor 263 serving as a temperature detector is installed in the reaction tube 203. By adjusting the power supply to the heater 207 based on temperature information detected by the temperature sensor 263, the temperature distribution in the processing chamber 201 is configured to be as desired.

[0033] As shown in FIG. 3, the controller 121, which is a control unit (control means), is configured as a computer including a CPU (Central Processing Unit) 121a, a RAM (Random Access Memory) 121b, a storage device 121c, and an I / O port 121d. The RAM 121b, the storage device 121c, and the I / O port 121d are configured to be able to exchange data with the CPU 121a via an internal bus 121e. An input / output device 122 configured as, for example, a touch panel is connected to the controller 121. An external storage device 123 can be connected to the controller 121. The substrate processing apparatus may be configured to include one control unit or multiple control units. That is, the control for performing the processing sequence described later may be performed using one control unit or multiple control units. The multiple control units may be configured as a control system connected to each other by a wired or wireless communication network, and the control for performing the processing sequence described later may be performed by the entire control system. In this specification, when the term "control section" is used, it may include one control section, or may include multiple control sections, or may include a control system made up of multiple control sections.

[0034] The storage device 121c is composed of, for example, a flash memory, an HDD (Hard Disk Drive), etc. A control program for controlling the operation of the substrate processing apparatus, a process recipe in which the procedures and conditions of the substrate processing described later are described, etc. are readably stored in the storage device 121c. The process recipe is a combination of procedures in the substrate processing step described later that are executed by the controller 121 to obtain a predetermined result, and functions as a program. Hereinafter, the process recipe and the control program are collectively referred to simply as a program. In addition, the process recipe is also simply referred to as a recipe. In this specification, when the word program is used, it may include only a recipe, only a control program, or both. The RAM 121b is configured as a memory area (work area) in which the programs and data read by the CPU 121a are temporarily stored.

[0035] The I / O port 121d is connected to the above-mentioned MFCs 241a to 241e, valves 243a to 243e, pressure sensor 245, APC valve 244, vacuum pump 246, heater 207, temperature sensor 263, rotation mechanism 267, boat elevator 115, matching box 272, high frequency power supply 273, and the like.

[0036] The CPU 121a is configured to read and execute a control program from the storage device 121c, and also to read a process recipe from the storage device 121c in response to an input of an operation command from the input / output device 122, etc. The CPU 121a is configured to control the flow rate adjustment operation of various gases by the MFCs 241a-241e, the opening and closing operation of the valves 243a-243e, the opening and closing operation of the APC valve 244 and the pressure adjustment operation by the APC valve 244 based on the pressure sensor 245, the start and stop of the vacuum pump 246, the temperature adjustment operation of the heater 207 based on the temperature sensor 263, the rotation and rotation speed adjustment operation of the boat 217 by the rotation mechanism 267, the raising and lowering operation of the boat 217 by the boat elevator 115, the impedance adjustment operation by the matching device 272, the power supply to the high frequency power source 273, etc., in accordance with the contents of the read process recipe.

[0037] The controller 121 can be configured by installing the above-mentioned program stored in an external storage device (for example, a magnetic tape, a magnetic disk such as a flexible disk or a hard disk, an optical disk such as a CD or a DVD, a magneto-optical disk such as an MO, or a semiconductor memory such as a USB memory or a memory card) 123 into a computer. The storage device 121c and the external storage device 123 are configured as computer-readable recording media. Hereinafter, these are collectively referred to simply as recording media. When the term recording media is used in this specification, it may include only the storage device 121c alone, only the external storage device 123 alone, or both. The program may be provided to the computer using a communication means such as the Internet or a dedicated line, without using the external storage device 123.

[0038] (2) Substrate processing An example of a sequence for forming a second film on a wafer 200 having a first film formed thereon as a base, using the above-mentioned substrate processing apparatus, as one step in a manufacturing process for a semiconductor device, will be described with reference to Fig. 4. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by a controller 121.

[0039] The substrate processing sequence shown in FIG. (a) a step of forming an intermediate layer containing carbon (C) and nitrogen (N) or an intermediate layer containing C without containing N on a first film formed on a wafer 200 as a substrate (an intermediate layer forming step); (b) forming a second film containing N on the intermediate layer using an activated N-containing gas (second film forming step). In this specification, the intermediate layer containing C and N and the intermediate layer containing C but not containing N may be collectively referred to as an intermediate layer containing C.

[0040] In this specification, the substrate processing sequence shown in FIG. 4 may be conveniently indicated as follows. In this specification, the N-containing gas activated by plasma excitation is conveniently referred to as N-containing gas. * The same notation will be used in the following explanation of the modified examples.

[0041] (raw material gas → C and N-containing gas) × m → (raw material gas → N-containing gas) * )×n ⇒ 2nd film / middle layer

[0042] The term "wafer" used in this specification may mean the wafer itself or a laminate of the wafer and a predetermined layer or film formed on its surface. The term "surface of a wafer" used in this specification may mean the surface of the wafer itself or the surface of a predetermined layer or the like formed on the wafer. When described in this specification, "forming a predetermined layer on a wafer" may mean forming a predetermined layer directly on the surface of the wafer itself or forming a predetermined layer on a layer or the like formed on the wafer. When used in this specification, the term "substrate" is synonymous with the term "wafer".

[0043] (Wafer charge and boat load) A plurality of wafers 200 are loaded (wafer charge) into the boat 217. Then, as shown in Fig. 1, the boat 217 supporting the plurality of wafers 200 is lifted by the boat elevator 115 and carried (boat load) into the processing chamber 201. In this state, the seal cap 219 seals the lower end of the reaction tube 203.

[0044] An oxide film as a first film is formed in advance on at least a part of the surface of the wafer 200. This film will be at least a part of the base film when forming an intermediate layer in the intermediate layer forming step described later. The oxide film may be formed so as to cover the entire surface of the wafer 200, or may be formed so as to cover only a part of it. As the oxide film, for example, a Si-containing film such as a silicon oxide film (SiO film), a silicon oxynitride film (SiON film), a silicon oxycarbide film (SiOC film), or a silicon oxycarbonitride film (SiOCN film), or a metal oxide film such as an aluminum oxide film (AlO film), a hafnium oxide film (HfO film), a zirconium oxide film (ZrO film), or a titanium oxide film (TiO film), i.e., a high dielectric constant insulating film (High-k film), may be formed. The oxide film (or oxynitride film, oxycarbonate film, or oxycarbonitride film) referred to here may include an oxide film intentionally formed by performing a predetermined process such as a CVD process, a plasma CVD process, a thermal oxidation process, or a plasma oxidation process, as well as a natural oxide film formed naturally when the wafer 200 is exposed to the atmosphere during transportation of the wafer 200. However, the first film is not limited to an oxide film, and may be another film that may form a transition layer between the first film and a second film described later. In addition, the first film is not limited to a film formed on the surface of the wafer 200, and the surface of the wafer 200 itself may constitute the first film as a base film.

[0045] (Pressure and temperature regulation) The vacuum pump 246 evacuates (reduced pressure exhausts) the processing chamber 201 so that the pressure in the space in which the wafers 200 are present becomes a desired pressure (vacuum level). At this time, the pressure in the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 244 is feedback-controlled based on the measured pressure information. The vacuum pump 246 is kept in a constantly operating state at least until the processing of the wafers 200 is completed. In addition, the wafers 200 in the processing chamber 201 are heated by the heater 207 so that the temperature of the wafers 200 becomes a desired temperature. In addition, the rotation mechanism 267 starts to rotate the boat 217 and the wafers 200. The rotation mechanism 267 continues to rotate the boat 217 and the wafers 200 at least until the processing of the wafers 200 is completed.

[0046] (Intermediate layer formation step) After that, the following two steps, namely, step S1a and step S1b, are executed.

[0047] [Step S1a] In this step, a source gas is supplied to the wafer 200 in the processing chamber 201 .

[0048] Specifically, the valve 243a is opened to allow the source gas to flow into the gas supply pipe 232a. The flow rate of the source gas is adjusted by the MFC 241a, supplied into the processing chamber 201 via the nozzle 249a, and exhausted from the exhaust pipe 231. At this time, the source gas is supplied to the wafer 200. At the same time, the valve 243d is opened to allow the inert gas to flow into the gas supply pipe 232d. The flow rate of the inert gas is adjusted by the MFC 241d, supplied into the processing chamber 201 together with the source gas, and exhausted from the exhaust pipe 231.

[0049] That is, in this step, the source gas is supplied toward the central region within the substrate surface, and the inert gas is supplied toward the central region of the wafer 200 together with the source gas.

[0050] The processing conditions for supplying the raw material gas in this step are as follows: Treatment temperature: 250 to 700°C, preferably 300 to 650°C, more preferably 350 to 600°C Treatment pressure: 1 to 2666 Pa, preferably 67 to 1333 Pa Raw material gas supply flow rate: 1 to 2000 sccm, preferably 10 to 1000 sccm Raw material gas supply time: 1 to 120 seconds, preferably 1 to 60 seconds Inert gas supply flow rate (each nozzle): 100 to 10,000 sccm From the viewpoint of increasing the processing speed, it is particularly preferable to set the processing temperature to be substantially the same in each step of the intermediate layer formation step.

[0051] In this disclosure, the expression of a numerical range such as "250 to 700°C" means that the lower limit and the upper limit are included in the range. Therefore, for example, "250 to 700°C" means "250°C or more and 700°C or less". The same applies to other numerical ranges. In this disclosure, the processing temperature means the temperature of the wafer 200 or the temperature in the processing chamber 201, and the processing pressure means the pressure in the processing chamber 201. Furthermore, the processing time means the time the processing continues. These also apply in the following explanations.

[0052] By supplying the source gas to the wafer 200 under the above-mentioned conditions, a first layer containing a predetermined element, for example, having a thickness of less than one atomic layer to several atomic layers, is formed on the wafer 200 (underlying film including the first film on the surface). For example, when a gas containing Si and Cl is used as the source gas, a Si-containing layer containing Cl is formed as the first layer. Note that O contained in the underlying first film may be incorporated into the first layer. In this specification, the first layer that has come to contain Cl or O (Si-containing layer containing O and Cl) may also be referred to simply as a Si-containing layer for convenience.

[0053] After the first layer is formed, the valve 243a is closed to stop the supply of the source gas. At this time, the APC valve 244 is left open, and the inside of the processing chamber 201 is evacuated by the vacuum pump 246 to remove the source gas remaining in the processing chamber 201 that has not reacted or that has contributed to the formation of the first layer from the inside of the processing chamber 201. At this time, the valves 243d and 243e are left open to maintain the supply of the inert gas into the processing chamber 201. The inert gas acts as a purge gas.

[0054] As the source gas, for example, an inorganic halosilane source gas such as hexachlorodisilane (Si2Cl6) gas, monochlorosilane (SiH3Cl) gas, dichlorosilane (SiH2Cl2) gas, trichlorosilane (SiHCl3) gas, tetrachlorosilane (SiCl4) gas, or octachlorotrisilane (Si3Cl8) gas can be used.

[0055] Also, as the source gas, an alkylenehalosilane source gas such as ethylenebis(trichlorosilane) gas, that is, 1,2-bis(trichlorosilyl)ethane ((SiCl3)2C2H4) gas, bis(trichlorosilyl)methane ((SiCl3)2CH2) gas, etc. can be used.

[0056] In addition, alkylhalosilane source gases such as 1,1,2,2-tetrachloro-1,2-dimethyldisilane ((CH3)2Si2Cl4) gas, 1,2-dichloro-1,1,2,2-tetramethyldisilane ((CH3)4Si2Cl2) gas, and 1-monochloro-1,1,2,2,2-pentamethyldisilane ((CH3)5Si2Cl) gas can also be used as the source gas.

[0057] As the source gas, inorganic source gas such as monosilane (SiH4) gas, disilane (Si2H6) gas, trisilane (Si3H8) gas, etc. can be used.

[0058] As the raw material gas, for example, aminosilane raw material gases such as tetrakisdimethylaminosilane (Si[N(CH3)2]4) gas, trisdimethylaminosilane (Si[N(CH3)2]3H) gas, bisdiethylaminosilane (Si[N(C2H5)2]2H2) gas, and bistertiarybutylaminosilane (SiH2[NH(C4H9)]2) gas can be used.

[0059] As the source gas, one or more of the above-mentioned gases can be used.

[0060] As the inert gas, for example, in addition to nitrogen (N2) gas, rare gases such as argon (Ar) gas, helium (He) gas, neon (Ne) gas, and xenon (Xe) gas can be used. As the inert gas, one or more of these can be used. The same applies to the inert gas in the following description.

[0061] [Step S1b] After step S1a is completed, a C and N containing gas is supplied to the wafer 200 in the processing chamber 201, that is, to the first layer formed on the first film 300.

[0062] Specifically, the valve 243c is opened to allow the C- and N-containing gas to flow into the gas supply pipe 232c. The C- and N-containing gas is adjusted in flow rate by the MFC 241c, supplied into the processing chamber 201 via the gas supply pipe 232b, the nozzle 249b, and the buffer chamber 237, and exhausted from the exhaust pipe 231. At this time, the C- and N-containing gas is supplied to the wafer 200. At the same time, the valve 243e is opened to allow the inert gas to flow into the gas supply pipe 232e. The inert gas is adjusted in flow rate by the MFC 241e and supplied into the processing chamber 201 together with the C- and N-containing gas.

[0063] That is, in this step, a C- and N-containing gas is supplied toward the central region of the substrate surface, and an inert gas is supplied toward the central region of the wafer 200 together with the C- and N-containing gas.

[0064] The processing conditions for supplying the C and N-containing gas in this step are as follows: Treatment pressure: 1 to 5000 Pa, preferably 1 to 4000 Pa C and N containing gas supply flow rate: 100 to 10,000 sccm C- and N-containing gas supply time: 1 to 200 seconds, preferably 1 to 120 seconds, more preferably 1 to 60 seconds Other processing conditions may be the same as those used when supplying the source gas.

[0065] By supplying the C- and N-containing gas to the wafer 200 under the above-mentioned conditions, the first layer formed on the wafer 200 in step S1a can be reacted with the C- and N-containing gas. Specifically, for example, Cl (chloro group), which is a halogen element (halogen group) contained in the first layer, can be reacted with the C-containing ligand contained in the C- and N-containing gas. As a result, at least a part of Cl contained in the first layer can be extracted (separated) from the first layer, and at least a part of the C-containing ligand contained in the C- and N-containing gas can be separated from the C- and N-containing gas. The C-containing ligand is, for example, an alkyl group such as an ethyl group or a methyl group composed of C and hydrogen (H). Then, N of the C- and N-containing gas from which at least a part of the C-containing ligand is separated can be bonded to Si contained in the first layer to form a Si-N bond. At this time, it is also possible to bond C contained in the C-containing ligand separated from the C- and N-containing gas to Si contained in the first layer to form a Si-C bond. As a result, Cl is released from the first layer, and N is newly incorporated into the first layer. At the same time, C is also newly incorporated into the first layer.

[0066] By supplying the C- and N-containing gas under the above-mentioned conditions, the first layer can be properly reacted with the C- and N-containing gas, and the above-mentioned series of reactions can be caused. This series of reactions causes the N component and the C component to be newly incorporated into the first layer, and the first layer is changed (modified) into a layer containing a predetermined element, C, and N. Specifically, for example, the second layer is changed into a silicon carbonitride layer (SiCN layer). This layer can also be called a SiN layer containing C. The second layer is a layer with a thickness of less than one atomic layer to several atomic layers. In addition, the second layer is a layer with a relatively high ratio of Si component and C component, that is, a layer that is Si-rich and C-rich.

[0067] After the second layer is formed, the valve 243c is closed to stop the supply of the C- and N-containing gas. Then, by a process procedure similar to that of step S1a, the C- and N-containing gas and reaction by-products remaining in the process chamber 201 that have not reacted or that have contributed to the formation of the second layer are removed from the process chamber 201.

[0068] As the C- and N-containing gas, for example, an organic hydrazine-based gas or an amine-based gas can be used.

[0069] As the organic hydrazine gas, a methylhydrazine gas such as monomethylhydrazine ((CH3)HN2H2) gas, dimethylhydrazine ((CH3)2N2H2) gas, trimethylhydrazine ((CH3)2N2(CH3)H) gas, etc. can be used. Also, as the organic hydrazine gas, an ethylhydrazine gas such as ethylhydrazine ((C2H5)HN2H2) gas can be used.

[0070] As the amine-based gas, for example, an ethylamine-based gas such as triethylamine ((C2H5)3N) gas, diethylamine ((C2H5)2NH) gas, or monoethylamine (C2H5NH2) gas can be used. As the amine-based gas, a methylamine-based gas such as trimethylamine ((CH3)3N) gas, dimethylamine ((CH3)2NH) gas, or monomethylamine (CH3NH2) gas can be used. As the amine-based gas, a propylamine-based gas such as tripropylamine ((C3H7)3N) gas, dipropylamine ((C3H7)2NH) gas, or monopropylamine (C3H7NH2) gas can be used. As the amine-based gas, an isopropylamine-based gas such as triisopropylamine ([(CH3)2CH]3N) gas, diisopropylamine ([(CH3)2CH]2NH) gas, or monoisopropylamine ((CH3)2CHNH2) gas can be used. As the amine gas, a butylamine gas such as tributylamine ((C4H9)3N) gas, dibutylamine ((C4H9)2NH) gas, monobutylamine (C4H9NH2) gas, etc., can also be used. As the amine gas, an isobutylamine gas such as triisobutylamine ([(CH3)2CHCH2]3N) gas, diisobutylamine ([(CH3)2CHCH2]2NH) gas, monoisobutylamine ((CH3)2CHCH2NH2) gas, etc. can also be used.

[0071] That is, the amine gas is, for example, (C2H5) x NH 3-x , (CH3) x NH 3-x , (C3H7) x NH 3-x , [(CH3)2CH] x NH 3-x , (C4H9) x NH 3-x , [(CH3)2CHCH2] x NH 3-x (wherein x is an integer of 1 to 3) can be used.

[0072] As the C and N-containing gas, one or more of the above-mentioned gases can be used.

[0073] (Performed a set number of times) By performing the above-mentioned steps S1a and S1b non-simultaneously, i.e., without synchronization, a cycle m times or more (m is an integer of 1 or 2 or more), an intermediate layer 400 containing predetermined elements, C and N can be formed on the first film 300 formed on the wafer 200 as shown in FIG. 5(A). That is, the intermediate layer 400 contains predetermined elements other than C and N. As the intermediate layer 400, for example, a SiCN layer containing Si, C and N as the predetermined elements can be formed. The intermediate layer 400 can also be referred to as a seed layer. Note that in step S1b, a C-containing gas not containing N may be used instead of the C- and N-containing gas, thereby forming a layer containing C not containing N (for example, a SiC layer) as the intermediate layer 400.

[0074] Here, in order to explain the effect of forming the intermediate layer 400 between the first film 300 and the second film 600, a case in which a nitride film as the second film 600 is directly formed on an oxide film as the first film 300 will first be described.

[0075] When the second film 600 is formed directly on the first film 300, oxygen (O), which is an element contained in the first film 300, may diffuse into the second film 600, which does not substantially contain O. Due to this diffusion of O, a layer (O diffusion layer) containing O in addition to the predetermined element and N is formed at the interface of the second film 600 with the first film 300. Due to the inclusion of O, this O diffusion layer has a different etching rate (i.e., different etching resistance) with respect to the second film 600. In other words, a transition layer is formed in the vicinity of the interface of the second film 600 with the first film 300 in the thickness direction from the second film 600 toward the first film 300, in which the magnitude of the etching rate transitions (changes) according to the diffusion concentration of O, etc.

[0076] The transition layer has a gradient of O concentration such that the closer to the first film 300 the O concentration is, the higher the O concentration is, and the further away from the first film 300 the O concentration is, the lower the O concentration is, and the etching rate of the transition layer also transitions according to the gradient of O concentration. More specifically, for example, when an etchant (e.g., hydrogen fluoride (HF) gas, diluted HF aqueous solution, etc.) having a high etching rate for an oxide film as the first film 300 and a low etching rate for a nitride film as the second film 600 is used, a layer in which the etching rate transitions to increase is formed in a part of the second film 600 in the thickness direction toward the first film 300.

[0077] For example, when it is desired to selectively remove only the first film 300 with respect to the second film 600 by etching, such a transition layer may cause etching not only of the first film 300, which is the etching target, but also of at least a part of the transition layer, which has a higher etching rate (lower etching resistance) than the second film 600, thereby reducing the controllability of the etching. Therefore, when forming the second film 600, it may be necessary to suppress the formation of such a transition layer or reduce the thickness of the transition layer that is formed.

[0078] In the disclosed technique, the intermediate layer 400 containing C is formed on the first film 300 in advance. When the second film 600 is formed on the intermediate layer 400, at least a part of the C contained in the intermediate layer 400 diffuses near the interface of the second film 600. Specifically, as shown in FIG. 5(B), a diffusion layer 500 containing C is formed near the interface between the intermediate layer 400 and the second film 600 by diffusing C into the second film 600 when the second film 600 is formed. The diffusion layer 500 has a gradient of the C concentration such that the C concentration is higher closer to the first film 300 and the C concentration is lower farther from the first film 300. Here, the C element contained in the intermediate layer 400 acts to reduce the etching rate (increase the etching resistance) of the part of the second film 600 where C is diffused. Therefore, C in the diffusion layer 500 acts to reduce the etching rate to a greater extent as it is closer to the first film 300, and to a lesser extent as it is farther away from the first film 300.

[0079] Here, as described above, the increase in the etching rate caused by O diffused from the first film 300 tends to be larger closer to the first film 300 and smaller farther from the first film 300 according to the gradient of the O concentration. Therefore, when forming the second film 600, by forming the diffusion layer 500 having a gradient of the C concentration similar to the O concentration, the formation of a transition layer caused by the diffusion of O can be suppressed or the thickness of the transition layer formed can be reduced. In FIG. 5(B), the transition layer whose thickness is reduced by forming the diffusion layer 500 is shown as the transition layer 700. The thickness of the transition layer 700 varies depending on the concentration distribution of C (in the thickness direction) and the concentration distribution of O in the diffusion layer 500. For example, the thickness of the transition layer 700 can be reduced or substantially eliminated (made zero) by adjusting the C content per unit area of ​​the intermediate layer 400 as described later.

[0080] The transition layer 700 can also be said to be a layer whose etching rate has changed due to diffusion of O into the second film 600, and whose etching rate is different from that of either the first film 300 or the second film 600.

[0081] Furthermore, the intermediate layer 400 containing C also functions as a block layer (diffusion barrier layer) that suppresses the diffusion of O from the underlying first film 300 to the second film 600 in the second film formation step, thereby achieving the effect of further reducing the thickness of the transition layer 700.

[0082] Furthermore, in the second film forming step described later, the N-containing gas is activated by plasma excitation, and the activated N-containing gas is used to form the second film 600, which is an N-containing film. At this time, radicals and the like contained in the activated N-containing gas have excessively high reactivity, and at least a part of the C contained in the intermediate layer 400 may be desorbed from the intermediate layer 400 by these radicals and the like without diffusing into the second film 600. In addition, since the activated N-containing gas is supplied from the outer edge (i.e., the outer region) of the wafer 200 toward the central region, more C is desorbed from the intermediate layer 400 in the outer region than in the central region in the substrate plane. In other words, the amount of C desorbed per unit area from the intermediate layer 400 differs between the central region and the outer region in the substrate plane, and the amount of C diffused per unit area into the second film 600 is less in the outer region than in the central region in the substrate plane.

[0083] More specifically, at least one of the thickness of the diffusion layer 500 and the C content (C concentration) per unit area in the diffusion layer 500 differs between the outer region and the central region. For example, in this case, the thickness of the diffusion layer 500 may be smaller in the outer region and larger in the inner region. Also, in this case, the C content (C concentration) in the diffusion layer 500 may be smaller in the outer region and larger in the central region.

[0084] Furthermore, at least one of the thickness of the diffusion layer 500 and the C content (C concentration) per unit area in the diffusion layer 500 is different between the central region and the outer region in the substrate plane, so that the thickness of the transition layer 700, which has a different etching rate, is different between the central region and the outer region in the substrate plane. More specifically, the thickness of the transition layer 700 in the outer region is larger than the thickness of the transition layer 700 in the central region depending on at least one of the thickness of the diffusion layer 500 and the C content (C concentration) per unit area in the diffusion layer 500. If the thickness of the transition layer 700 in the substrate plane becomes non-uniform in this way, at least a part of the transition layer 700 is etched together with the first film 300 during the etching process for the first film 300, so that the thickness of the remaining second film 600 in the substrate plane may become non-uniform. For this reason, it is desirable that the thickness of the transition layer 700 is as thin as possible and uniform in the substrate plane.

[0085] Therefore, in the disclosed technique, in the above-mentioned intermediate layer forming step, the intermediate layer 400 is formed so that the amount of C contained per unit area in the intermediate layer 400 is different between the central region and the outer region in the substrate plane. For example, the intermediate layer 400 is formed so that the amount of C contained per unit area in the intermediate layer 400 is different between the center and the outer edge (periphery) in the substrate plane. Specifically, the intermediate layer 400 is formed so that the C content per unit area contained in the intermediate layer 400 is greater in the outer region than in the central region. By forming the intermediate layer 400 in this manner, even under conditions in which the C in the intermediate layer 400 in the outer region of the wafer 200 is more likely to be desorbed than the C in the intermediate layer 400 in the central region of the wafer 200 in the second film forming step, the amount of C per unit area diffused in the second film 600 (i.e., the C content of the diffusion layer 500 per unit area) can be distributed in the substrate plane as desired in the second film forming step. This also allows the thickness of the transition layer 700 to be distributed in the substrate plane as desired, for example, uniformly. That is, by adjusting the in-plane distribution of the C content of intermediate layer 400, it is possible to reduce the variation in the thickness distribution of transition layer 700 and make it closer to uniform.

[0086] The distribution of the C content per unit area contained in the intermediate layer 400 is adjusted in the intermediate layer formation step described above, for example, by adjusting the thickness of the intermediate layer 400 within the substrate surface or the C concentration contained in the intermediate layer 400.

[0087] For example, in this step, the intermediate layer 400 is formed so that the thickness of the intermediate layer 400 is different between the central region and the outer region in the substrate plane. Specifically, the intermediate layer 400 is formed so that the thickness of the intermediate layer 400 is greater in the outer region than in the central region in the substrate plane. By adjusting the thickness of the intermediate layer 400, the distribution of the C content per unit area in the substrate plane can be controlled.

[0088] More specifically, in the above-mentioned step S1a, the pressure of the processing space (i.e., processing chamber 201) in which the wafer 200 is processed is set to be higher than the pressure at which the thickness of the intermediate layer 400 becomes uniform within the substrate surface. By increasing the pressure of the processing space, the mean free path in the processing space is reduced, and the source gas is promoted to be adsorbed in the outer region within the substrate surface. By adsorbing more source gas in the outer region within the substrate surface than in the central region, the thickness of the intermediate layer 400 in the outer region within the substrate surface can be adjusted to be larger than the thickness of the intermediate layer 400 in the central region. In other words, the thickness of the intermediate layer 400 can be adjusted to have a concave distribution within the substrate surface.

[0089] In addition, in the above-mentioned step S1a, the time for supplying the raw material gas is set to be shorter than the time for the thickness of the intermediate layer 400 to become uniform within the substrate surface. By shortening the supply time of the raw material gas, the amount of raw material gas that reaches the central region of the wafer 200 is reduced. As a result, the thickness of the intermediate layer 400 in the outer region within the substrate surface can be adjusted to be larger than the thickness of the intermediate layer 400 in the central region. In other words, the thickness of the intermediate layer 400 can be adjusted to have a concave distribution within the substrate surface.

[0090] Furthermore, in the above-mentioned step S1a, the flow rate of the inert gas supplied from nozzle 249a simultaneously with the raw material gas and the flow rate of the inert gas supplied from nozzle 249b are set to be greater than the flow rate of the inert gas at which the thickness of intermediate layer 400 becomes uniform within the substrate surface. By increasing the flow rate of the inert gas supplied toward the central region of wafer 200, the partial pressure of the raw material gas supplied to the central region is reduced, and the partial pressure of the raw material gas supplied to the outer region is relatively increased. This makes it possible to adjust the thickness of intermediate layer 400 in the outer region within the substrate surface to be greater than the thickness of intermediate layer 400 in the central region. In other words, the thickness of intermediate layer 400 is adjusted to be greater than the thickness of intermediate layer 400 in the central region within the substrate surface. It can be adjusted to have a concave distribution.

[0091] The average thickness of the intermediate layer 400 within the substrate surface is, for example, within a range of 7 to 35 Å, preferably 23 to 30 Å.

[0092] If the average thickness of the intermediate layer 400 in the substrate plane is less than 7 Å, it may be difficult to obtain the effect of reducing the thickness of the transition layer 700 formed in the second film formation step. By making the average thickness of the intermediate layer 400 in the substrate plane 7 Å or more, the effect of reducing the thickness of the transition layer 700 can be obtained. By making the average thickness of the intermediate layer 400 in the substrate plane 23 Å or more, the effect of reducing the thickness of the transition layer 700 can be obtained more reliably.

[0093] If the average thickness of the intermediate layer 400 in the substrate plane exceeds 35 Å, the amount of C per unit area diffused into the second film 600 becomes too large, and it may be difficult to obtain desired characteristics such as electrical characteristics for the second film 600. By setting the average thickness of the intermediate layer 400 in the substrate plane to 35 Å or less, it becomes easier to obtain desired characteristics for the second film 600. By setting the average thickness of the intermediate layer 400 in the substrate plane to 30 Å or less, it becomes easier to obtain desired characteristics for the second film 600.

[0094] Moreover, it is desirable that the difference (also called deviation) in thickness between the center and the outer periphery (outer edge) of the substrate surface in the central region and outer region of the intermediate layer 400 is, for example, 4 to 10 Å, and preferably 5 to 8 Å. The magnitude of the deviation can be selected according to the magnitude of the deviation in the amount of C desorbed from the intermediate layer 400 in the second film formation step within the substrate surface.

[0095] As described above, when the thickness of the intermediate layer 400 in the outer region within the substrate surface in step S1a is adjusted to be larger than the thickness of the intermediate layer 400 in the central region, it is preferable that the thickness of the second film 600 formed in the second film forming step described below is larger in the central region than in the outer region within the surface of the wafer 200. This allows the total thickness of the film formed by stacking the intermediate layer 400 and the second film 600 to be closer to uniform within the surface of the wafer 200.

[0096] Also, for example, in this step, the intermediate layer 400 is formed so that the C concentration in the intermediate layer 400 is different between the central region and the outer region within the substrate surface. In other words, the intermediate layer 400 is formed so that the C concentration in the intermediate layer 400 is higher in the outer region than in the central region within the substrate surface. By adjusting the C concentration in the intermediate layer 400, the distribution of the C content per unit area within the substrate surface can be controlled.

[0097] Specifically, in the above-mentioned step S1b, the pressure of the processing space in which the wafer 200 is processed is set to be higher than the pressure at which the thickness of the C concentration contained in the intermediate layer 400 becomes uniform within the substrate surface. By adjusting the pressure of the processing space during the supply of the C- and N-containing gas to increase the pressure of the processing space, the mean free path in the processing space is reduced, and the C- and N-containing gas is promoted to be adsorbed to the outer region within the substrate surface. As a result, the C concentration in the intermediate layer 400 in the outer region can be adjusted to be higher than the C concentration in the intermediate layer 400 in the central region.

[0098] In step S1b described above, the supply time of the C- and N-containing gas is set shorter than the time required for the C concentration in the intermediate layer 400 to become uniform across the substrate surface. By adjusting the supply time of the C- and N-containing gas to shorten the supply time of the C- and N-containing gas, the amount of the C- and N-containing gas that reaches the central region of the wafer 200 is reduced, and as a result, the C concentration in the intermediate layer 400 in the outer regions can be adjusted to be higher than the C concentration in the intermediate layer 400 in the central region.

[0099] In step S1b, the flow rates of the inert gas supplied from nozzle 249b simultaneously with the C- and N-containing gas and the inert gas supplied from nozzle 249a are set to be greater than the flow rate of the inert gas that makes the C concentration in intermediate layer 400 uniform within the substrate surface. By increasing the flow rate of the inert gas supplied toward the central region, the partial pressure of the C- and N-containing gas supplied to the central region is reduced, and the partial pressure of the C- and N-containing gas supplied to the outer region is relatively increased. This allows the C concentration of the intermediate layer in the outer region within the substrate surface to be adjusted to be greater than the C concentration in intermediate layer 400 in the central region.

[0100] The average C concentration in the substrate surface of the intermediate layer 400 is, for example, 3 to 15%, and preferably 5 to 7%.

[0101] If the average C concentration in the substrate surface of the intermediate layer 400 is less than 3%, it may be difficult to obtain the effect of reducing the thickness of the transition layer 700 formed in the second film formation step. By making the average C concentration in the substrate surface of the intermediate layer 400 3% or more, the effect of reducing the thickness of the transition layer 700 can be obtained. By making the average C concentration in the substrate surface of the intermediate layer 400 5% or more, the effect of reducing the thickness of the transition layer 700 can be obtained more reliably.

[0102] If the average C concentration in the substrate surface of the intermediate layer 400 exceeds 15%, the C content per unit area of ​​the intermediate layer 400 becomes too high, which may make it difficult to obtain desired characteristics such as electrical characteristics for the second film 600. By setting the average C concentration in the substrate surface of the intermediate layer 400 to 15% or less, it becomes easier to obtain desired characteristics for the second film 600. By setting the average C concentration in the substrate surface of the intermediate layer 400 to 7% or less, it becomes easier to obtain desired characteristics.

[0103] The difference (also called deviation) in concentration between the center and the outer periphery (edge) of the substrate surface in the central region and outer region of the intermediate layer 400 is, for example, 0.3 to 2.2%, preferably 0.7 to 1.8%. The magnitude of the deviation can be selected according to the magnitude of the bias in the amount of C desorbed from the intermediate layer 400 in the second film formation step within the substrate surface.

[0104] Furthermore, by adjusting the distribution of the C concentration contained in the intermediate layer 400 while making the distribution of the thickness of the intermediate layer 400 uniform in the in-plane direction of the substrate, it becomes easy to make the thickness of the film formed by stacking the intermediate layer 400 and the second film 600 closer to uniform in the plane of the wafer 200.

[0105] After the intermediate layer forming step is performed, a second film forming step is performed in which a C-free N-containing layer is formed by using a plasma-excited N-containing gas. In this embodiment, the step of forming a C-free N-containing layer (i.e., a C-free N-containing layer) on the intermediate layer 400 without using plasma excitation is not performed. In other words, after the intermediate layer forming step is performed and before the second film forming step is started, the step of forming a C-free N-containing layer on the intermediate layer 400 without using plasma excitation is not performed. This makes it possible to omit the step of forming a C-free N-containing layer without using plasma excitation and improve productivity.

[0106] In addition, when the N-containing layer is formed without using plasma excitation in the second film formation step, it may be necessary to perform substrate processing at a processing temperature higher than both the intermediate layer formation step and the second film formation step. That is, in order to form the N-containing layer using thermally excited N-containing gas, the N-containing layer may be formed at a higher temperature than when the N-containing layer is formed using plasma excitation. By not performing such a process of forming the N-containing layer using thermal excitation, it is possible to suppress the deterioration of device characteristics due to thermal history. In addition, by not performing such a process of forming the N-containing layer using thermal excitation, it is possible to maintain the temperature of the wafer 200 at a temperature that does not exceed at least one of the temperature of the wafer 200 in the intermediate layer formation step and the temperature of the wafer 200 in the second film formation step from the start of the intermediate layer formation step to the end of the second film formation step.

[0107] In this step, the distribution of the C content per unit area contained in the intermediate layer 400 is set so that after the next second film formation step is performed, the thickness of the transition layer 700 has a predetermined distribution, for example uniform, within the substrate surface.

[0108] (Second film formation step) After the formation of the intermediate layer 400 is completed, the next two steps, namely, steps S2a and S2b, are performed. That is, a second film 600 containing N is formed on the intermediate layer 400 using an N-containing gas activated by plasma excitation.

[0109] [Step S2a] In this step, a source gas is supplied to the wafer 200 in the processing chamber 201, that is, to the intermediate layer 400 formed on the first film 300. The processing procedure of this step is the same as the processing procedure of step S1a. The processing conditions for supplying the raw material gas in this step are as follows: Treatment temperature: room temperature (25°C) to 550°C, preferably 400 to 500°C Examples include: Other process conditions may be the same as those in step S1a when supplying the source gas. In order to increase the deposition rate per film formation cycle of the second film 600, at least one of the process conditions in step S2a, such as the supply flow rate and the supply time of the source gas, may be set to be greater than those in step S1a.

[0110] By performing step S2a, a Si-containing layer is formed on intermediate layer 400 as a third layer.

[0111] [Step S2b] After step S2a is completed, the N-containing gas activated by plasma excitation is supplied to the wafer 200 in the processing chamber 201, that is, to the third layer formed on the intermediate layer 400.

[0112] Specifically, the valve 243b is opened to allow the N-containing gas to flow into the gas supply pipe 232b. The N-containing gas is adjusted in flow rate by the MFC 241b, and is supplied to the processing chamber 201 through the gas supply pipe 232b and the nozzle 249b after being plasma-excited in the buffer chamber 237, and is exhausted from the exhaust pipe 231. At this time, the N-containing gas activated by plasma excitation is supplied to the wafer 200. At the same time, the valve 243e is opened to allow the inert gas to flow into the gas supply pipe 232e. The inert gas is adjusted in flow rate by the MFC 241e, and is supplied to the processing chamber 201 together with the N-containing gas.

[0113] The processing conditions for supplying the N-containing gas in this step are as follows: Processing pressure: 1~100Pa N-containing gas supply flow rate: 100 to 10,000 sccm N-containing gas supply time (irradiation time): 1 to 120 seconds, preferably 1 to 60 seconds High frequency power: 50~1000W Other process conditions may be the same as those in step S2a when the source gas is supplied. Note that the process temperature in this step is preferably lower than that in step S2c in a modified example described later.

[0114] By supplying the N-containing gas activated by plasma excitation to the wafer 200 under the above-mentioned conditions, the formation speed of the second film 600 can be increased and the productivity can be improved compared to the case where the N-containing gas activated only by thermal excitation is used. In addition, it may become easier to improve the film quality of the second film 600 and suppress the processing temperature.

[0115] By supplying the activated N-containing gas to the wafer 200 under the above-mentioned conditions, at least a part of the third layer is nitrided (modified). By modifying the third layer, a fourth layer, i.e., a layer containing a predetermined element and N and substantially free of O and C (i.e., an O- and C-free N-containing layer), is formed on the wafer 200, i.e., on the intermediate layer 400. When the fourth layer is formed, impurities such as Cl contained in the third layer constitute a gaseous substance containing at least Cl during the process of the modification reaction by the N-containing gas, and are discharged from the processing chamber 201.

[0116] After the fourth layer is formed, the valve 243b is closed to stop the supply of the N-containing gas, and the N-containing gas and reaction by-products remaining in the process chamber 201 that have not reacted or that have contributed to the formation of the fourth layer are removed from the process chamber 201 by a process procedure similar to that of step S1a.

[0117] As the N-containing gas, for example, ammonia (NH3) gas, diazane (N2H2) gas, hydrazine (N2H4) gas, N3H8 gas, or other hydrogen nitride gas can be used. One or more of these can be used as the N-containing gas.

[0118] (Performed a set number of times) By performing the above-mentioned steps S2a and S2b non-simultaneously, i.e., without synchronization, a cycle is performed n times (n is an integer of 1 or 2 or more), a second film 600 containing a predetermined element and N can be formed on the intermediate layer 400. As the second film 600, for example, a SiN film containing Si and N as the predetermined elements can be formed.

[0119] The second film 600 has a higher etching resistance and a lower etching rate than the first film 300. The thickness of the second film 600 is greater than the thickness of the intermediate layer 400. By making the thickness of the second film 600 greater than the thickness of the intermediate layer 400, it is possible to form the second film 600 that does not include the diffusion layer 500 and does not contain C even after the second film formation step. The thickness of the second film 600 can be, for example, 15 to 500 Å, preferably 20 to 200 Å, and more preferably 30 to 100 Å.

[0120] As shown in FIG. 5(B), in the second film formation step, the C element contained in the intermediate layer 400 diffuses into the second film 600, and the intermediate layer 400 and a part of the second film 600 containing the diffused C form a diffusion layer 500 containing C.

[0121] In this step, at least a portion of the C contained in the intermediate layer 400 is desorbed so that the distribution of the C content per unit area contained in the diffusion layer 500 after carrying out this step becomes closer to uniform within the substrate surface.

[0122] As described above, in the second film formation step, at least a portion of the C contained in the intermediate layer 400 is desorbed so that the thickness of the transition layer 700 has a predetermined distribution within the substrate surface, for example, approaches uniformity.

[0123] That is, in the intermediate layer forming step, the intermediate layer 400 is formed so that the C content per unit area contained in the intermediate layer 400 is greater in the outer region than in the central region, and in the second film forming step, C is desorbed from the intermediate layer 400 so that the amount of C desorbed per unit area from the intermediate layer 400 is greater in the outer region than in the central region. In this case, the distribution of the C content per unit area contained in the intermediate layer 400 formed in the intermediate layer forming step is set according to the difference between the amount of C desorbed per unit area from the intermediate layer 400 in the central region of the substrate surface in the second film forming step and the amount of C desorbed per unit area from the intermediate layer 400 in the outer region of the substrate surface in the second film forming step. This makes it possible to make the C content per unit area contained in the diffusion layer 500 after the second film forming step closer to uniform in the substrate surface, and to make the thickness of the transition layer 700 closer to uniform in the substrate surface.

[0124] (Purge step / atmospheric pressure return step) After the formation of the second film 600 is completed, an inert gas is supplied into the processing chamber 201 from each of the gas supply pipes 232d and 232e, and exhausted from the exhaust pipe 231. The inert gas acts as a purge gas. This purges the processing chamber 201, and the gas and reaction by-products remaining in the processing chamber 201 are removed from the processing chamber 201 (purging). Thereafter, the atmosphere in the processing chamber 201 is replaced with the inert gas, and the pressure in the processing chamber 201 is returned to normal pressure.

[0125] (Exit step) Thereafter, the processed wafers 200 are transferred from the lower end of the reaction tube 203 to the outside of the reaction tube 203 while being supported by the boat 217 (boat unloading) by the boat elevator 115. After being transferred to the outside of the reaction tube 203, the processed wafers 200 are taken out of the boat 217 (wafer discharging).

[0126] (3) Etching process After the wafer 200 is unloaded from the processing chamber 201, further film formation processing, resist pattern formation processing, etc. are performed on the wafer 200 after the substrate processing. Then, the wafer 200 after these processing is loaded into a reaction vessel equipped in an etching device. Then, in a state in which the inside of the reaction vessel is controlled to have a predetermined processing pressure and processing temperature, an etching agent is supplied to the wafer 200 in the reaction vessel, thereby performing an etching process on the first film 300 formed on the surface of the wafer 200, etc.

[0127] An etching gas can be used as the etching agent. For example, hydrogen fluoride (HF) gas diluted with N2 gas, fluorine gas such as fluorine (F2) gas, or chlorine gas such as hydrogen chloride (HCl) gas can be used as the etching gas. One or more of these can be used. It is also possible to use a mixture of these gases, to add H-containing gas (reducing gas) such as H2 gas to these gases, or to activate these gases with plasma. In addition, it is also possible to use an etching liquid such as an HF aqueous solution or an HCl aqueous solution, instead of a gas, as the etching agent.

[0128] (4) Variations The substrate processing sequence in this embodiment is not limited to the embodiment shown in FIG. 4, and can be modified as in the following modified examples.

[0129] (Variation 1) In this modification, step S2c described below is executed instead of step S2b of the second film formation step described above. That is, in the second film formation step described above, the N-containing gas is thermally activated by thermal excitation in a non-plasma state and supplied. The substrate processing sequence of this modification can also be shown as follows.

[0130] (raw material gas → C- and N-containing gas) × m → (raw material gas → N-containing gas) × n → second film / intermediate layer

[0131] In this modification, the process procedure and process conditions in the intermediate layer forming step and the second film forming step S2a are the same as those in the intermediate layer forming step and the second film forming step S2a in the substrate processing sequence shown in Fig. 4. The process procedure and process conditions in step S2c are the same as those in step S2b, except for the points described below. However, it is more preferable that at least the process temperature among the process conditions in step S2a is the same as in step S2c.

[0132] [Step S2c] After step S2a is completed, a nitrogen-containing gas that is activated by heating (that is, thermally excited) is supplied to the wafer 200 in the processing chamber 201, that is, to the third layer formed on the intermediate layer 400.

[0133] Specifically, the valve 243b is opened to allow the N-containing gas to flow into the gas supply pipe 232b. The N-containing gas is adjusted in flow rate by the MFC 241b, supplied into the processing chamber 201 through the nozzle 249b, and exhausted from the exhaust pipe 231. At the same time, the valve 243e is opened to allow the inert gas to flow into the gas supply pipe 232e. The inert gas is adjusted in flow rate by the MFC 241e, and supplied into the processing chamber 201 together with the N-containing gas.

[0134] The processing conditions for supplying the N-containing gas in this step are as follows: Treatment temperature: 250 to 700°C, preferably 300 to 650°C, more preferably 350 to 600°C Treatment pressure: 1 to 4000 Pa, preferably 1 to 3000 Pa N-containing gas supply flow rate: 100 to 10,000 sccm N-containing gas supply time: 1 to 120 seconds, preferably 1 to 60 seconds Other processing conditions can be the same as those in the supply of the raw material gas in the intermediate layer forming step. Note that the processing temperature in this step is preferably higher than that in step S2b in the above embodiment.

[0135] By setting the pressure inside the processing chamber 201 to such a relatively high pressure zone, it becomes possible to thermally activate the N-containing gas without plasma.

[0136] In this modification, the same effect as that of the above-mentioned embodiment can be obtained. In addition, in this modification, by using the N-containing gas activated only by thermal excitation, it may be easier to reduce the amount of C desorbed from the intermediate layer 400 in the second film formation step and reduce the bias of the amount of C desorbed in the substrate surface, compared to the case of using the N-containing gas activated by plasma excitation.

[0137] Furthermore, by reducing the C content per unit area contained in the intermediate layer 400 formed in the intermediate layer formation step, or by reducing the deviation within the substrate surface of the C content per unit area contained in the intermediate layer 400 formed in the intermediate layer formation step, it becomes easy to obtain the desired thickness and distribution variation of the transition layer 700 after the second film formation step is performed.

[0138] (Variation 2) In this modification, as shown in Fig. 6(A), a first intermediate layer 400a containing C and N is formed on a first film 300, and then a second intermediate layer 400b containing N, which is a cap layer and a thermally nitrided layer, is formed on the first intermediate layer 400a. The second intermediate layer 400b is, for example, a thermally nitrided SiN film. Then, a second film 600 is formed on the second intermediate layer 400b.

[0139] That is, after the first intermediate layer formation step is performed similarly to the intermediate layer formation step of the substrate processing sequence shown in FIG. 4 described above, a second intermediate layer formation step is performed in which the N-containing gas is thermally activated. That is, between the intermediate layer formation step and the second film formation step in the substrate processing sequence shown in FIG. 4 described above, a step similar to the second film formation step in the above-mentioned modified example 1 is performed as the second intermediate layer formation step (however, the number of times the cycle including steps S2a and S2c is performed is different). That is, a second intermediate layer 400b containing N, which has a lower C concentration than the C concentration contained in the first intermediate layer 400a or is substantially free of C, is formed on the first intermediate layer 400a using an N-containing gas thermally activated without using plasma excitation. The substrate processing sequence of this modified example can also be shown as follows.

[0140] (raw material gas → C- and N-containing gas) × m → (raw material gas → N-containing gas) × p → (raw material gas → N-containing gas) * ) ⇒ 2nd membrane / 2nd intermediate layer / 1st intermediate layer

[0141] The process procedure and process conditions of the first intermediate layer formation step for forming the first intermediate layer 400a are the same as the process procedure and process conditions of the intermediate layer formation step in the substrate processing sequence shown in Fig. 4. The process procedure and process conditions of the second intermediate layer formation step for forming the second intermediate layer 400b are the same as the process procedure and process conditions of the second film formation step (i.e., the thermal nitridation second film formation step) in the above-mentioned modification 1. The second film formation step for forming the second film 600 is the same as the process procedure and process conditions of the second film formation step (i.e., the plasma nitridation second film formation step) in the above-mentioned substrate processing sequence shown in Fig. 4.

[0142] This modification also provides the same effect as the above-mentioned embodiment. Moreover, in this modification, the amount of C desorbed from the first intermediate layer 400a can be reduced in the second film formation step. That is, the second intermediate layer 400b can function as a cap layer that reduces or prevents desorption of C from the first intermediate layer 400a. By forming the second film 600 on the second intermediate layer 400b, a part of C contained in the first intermediate layer 400a may diffuse into the second intermediate layer 400b. Specifically, as shown in FIG. 6B, for example, in the first intermediate layer 400a and the second intermediate layer 400b, a diffusion layer 500 containing C may be formed by diffusing C into the second intermediate layer 400b when the second film 600 is formed. Moreover, even if the content of C per unit area contained in the first intermediate layer 400a formed in the first intermediate layer formation step is reduced, it is easy to make the thickness of the transition layer 700 after the second film formation step is performed to be the desired thickness.

[0143] Furthermore, in the second intermediate layer formation step in this modification, the second intermediate layer 400b is formed so that, for example, the thickness of the second intermediate layer 400b is greater in the outer region than in the central region in the substrate surface. In this way, by increasing the effect of reducing or preventing C desorption in the outer region in the second film formation step compared to that in the central region, for example, even if the first intermediate layer 400a is formed so that the C content contained in the first intermediate layer 400a is uniform in the substrate surface, the transition layer 700 can be made uniform. That is, in the second film formation step, when the amount of C desorbed in the outer region is greater than that in the central region, the amount of C desorbed from the first intermediate layer 400a can be adjusted to be closer to uniform in the substrate surface.

[0144] The thickness of the second intermediate layer 400b is smaller than that of the second film 600, and is, for example, 5 Å or more, preferably 10 Å or more, more preferably 15 Å or more, and even more preferably 20 Å or more.

[0145] If the thickness of the second intermediate layer 400b is less than 5 Å, it may be difficult to obtain the effect of reducing the desorption of C from the first intermediate layer 400a in the second film formation step using plasma excitation. By making the thickness of the second intermediate layer 400b 5 Å or more, the effect of reducing the desorption of C from the first intermediate layer 400a can be obtained. Furthermore, by making the thickness 10 Å or more, the effect of reducing the desorption of C from the first intermediate layer 400a can be obtained more reliably. Furthermore, by making the thickness 15 Å or more, the desorption of C from the first intermediate layer 400a can be substantially prevented. Furthermore, by making the thickness 20 Å or more, the effect of preventing the desorption of C from the first intermediate layer 400a can be obtained more remarkably.

[0146] In the first intermediate layer forming step, the first intermediate layer 400a may be formed so that the thickness of the first intermediate layer 400a is greater in the outer region than in the central region in the substrate plane, and in the second intermediate layer forming step, the second intermediate layer 400b may be formed so that the thickness of the second intermediate layer 400b is greater in the central region than in the outer region in the substrate plane. In this way, when the first intermediate layer 400a is concave, the second intermediate layer 400b can be formed convex to improve the film thickness uniformity in the substrate plane. The total film thickness of the first intermediate layer 400a and the second intermediate layer 400b can be made closer to uniform in the substrate plane.

[0147] (Variation 3) In this modification, in the intermediate layer forming step, a cycle of supplying a raw material gas to the wafer 200, supplying a C-containing gas to the wafer 200, and supplying an N-containing gas to the wafer 200 is performed a predetermined number of times (m1 times) to form the intermediate layer 400 on the first film 300. That is, instead of the step of supplying a C- and N-containing gas in the above-mentioned step S1b, a C-containing gas and an N-containing gas are supplied separately to form a film containing a predetermined element, C, and N. In this case, by using a C-containing gas supply system and an N-containing gas supply system instead of the C- and N-containing gas supply system, each gas can be supplied separately. Also, in this case, the N-containing gas supply system used in step S2b can be used as the N-containing gas supply system used in the intermediate layer forming step. The substrate processing sequence of this modification can also be shown as follows.

[0148] (raw material gas → C-containing gas → N-containing gas) × m1 → (raw material gas → N-containing gas * )×n1 ⇒ 2nd film / middle layer

[0149] In the step of supplying the C-containing gas, the supply flow rate of the C-containing gas is, for example, within a range of 100 to 10000 sccm. The pressure inside the processing chamber 201 is, for example, within a range of 1 to 5000 Pa, preferably within a range of 1 to 4000 Pa. The time for supplying the C-containing gas to the wafer 200 is, for example, within a range of 1 to 200 seconds, preferably within a range of 1 to 120 seconds, more preferably within a range of 1 to 60 seconds. Other processing conditions are, for example, the same as the processing conditions in the intermediate layer forming step in the above-mentioned embodiment.

[0150] In this modification, for example, a hydrocarbon gas can be used as the C-containing gas. The hydrocarbon gas can be said to be a substance composed of only two elements, C and H. For example, a propylene (C3H6) gas can be used as the hydrocarbon gas. In addition, as in the above embodiment, for example, a C- and N-containing gas can be used as the C-containing gas in this modification.

[0151] The process procedure and process conditions of the step of supplying the N-containing gas in the intermediate layer forming step are the same as those of step S2c in the above-mentioned modified example 1. In addition, the process procedure and process conditions of the step of supplying the source gas in the intermediate layer forming step and the second film forming step are the same as those of the corresponding steps in the above-mentioned embodiment.

[0152] In this modification, the same effects as those of the above-mentioned embodiment can be obtained. In addition, in the intermediate layer forming step, the C-containing gas as a C source and the N-containing gas as an N source can be supplied to the wafer 200 as separate gases, so that it becomes easier to control the amount (concentration) of C and N contained in the intermediate layer by adjusting the supply conditions (e.g., supply flow rate, supply time, supply pressure, etc.) of the C-containing gas and the N-containing gas.

[0153] (Variation 4) In this modification, different source gases are used in the intermediate layer forming step and the second film forming step of the above-mentioned substrate processing sequence. The substrate processing sequence of this modification can be expressed as follows.

[0154] (First source gas → C and N-containing gas) × m → (Second source gas → N-containing gas * )×n ⇒ 2nd film / middle layer (First source gas → C- and N-containing gas) × m → (Second source gas → N-containing gas) × n → Second film / intermediate layer (First source gas → C-containing gas → N-containing gas) × m1 → (Second source gas → N-containing gas * )×n1 ⇒ 2nd film / middle layer

[0155] Furthermore, in this modification, different source gases are used in the first intermediate layer formation step, the second intermediate layer formation step, and the second film formation step of the above-mentioned substrate processing sequence. The substrate processing sequence of this modification can be shown as follows. Any two of the first to third source gases may be the same gas.

[0156] (First source gas → C and N-containing gas) × m → (Second source gas → N-containing gas) × p → (Third source gas → N-containing gas * ) ⇒ 2nd membrane / 2nd intermediate layer / 1st intermediate layer

[0157] In this modified example as well, the same effects as those of the above embodiment can be obtained.

[0158] <Other aspects> Although one embodiment of the present disclosure has been specifically described above, the present disclosure is not limited to the above embodiment and can be modified in various ways without departing from the spirit and scope of the present disclosure.

[0159] For example, in the above embodiment, the intermediate layer forming step and the second film forming step are performed consecutively (in-situ) in the same processing chamber 201. The present disclosure is not limited to this, and the intermediate layer forming step and the second film forming step may be performed separately (ex-situ) in different processing chambers (processing vessels). In this case, the same effects as those of the above embodiment can be obtained.

[0160] In the above-mentioned embodiment, an example of processing a film using a batch-type substrate processing apparatus that processes multiple substrates at a time has been described. The present disclosure is not limited to the above-mentioned embodiment, and can be suitably applied to, for example, a case where a film is processed using a single-wafer type substrate processing apparatus that processes one or several substrates at a time. In addition, in the above-mentioned embodiment, an example of processing a film using a substrate processing apparatus having a hot-wall type processing furnace has been described. The present disclosure is not limited to the above-mentioned embodiment, and can be suitably applied to, for example, a case where a film is processed using a substrate processing apparatus having a cold-wall type processing furnace.

[0161] When using these substrate processing apparatuses, each process can be performed according to the same process procedures and under the same process conditions as in the above-mentioned aspects and modifications, and the same effects as in the above-mentioned aspects and modifications can be obtained.

[0162] The above-mentioned aspects and modifications may be used in appropriate combination. The processing procedures and processing conditions in this case may be the same as those of the above-mentioned aspects and modifications. EXAMPLES

[0163] The following describes experimental results that support the effects of the above-mentioned aspects and modifications. The processing conditions in each step of preparing the evaluation samples were set to be within the range of processing conditions in each step of the above-mentioned aspects.

[0164] FIG. 7 shows the results of evaluation of the etching resistance (processing resistance) of evaluation samples 1 to 5, each having an intermediate layer 400 with a different thickness.

[0165] In the evaluation samples 1 to 4, a SiCN layer was formed as an intermediate layer on the SiO film formed on the substrate surface by using the substrate processing apparatus in the above-described embodiment, and a plasma nitrided SiN film was formed on the SiCN layer by the substrate processing sequence shown in Fig. 4. In the evaluation samples 1 to 4, the thicknesses of the SiCN layer were set to 2 Å, 4 Å, 6 Å, and 7 Å, respectively.

[0166] For evaluation sample 5, the substrate processing apparatus in the above-described embodiment was used, and the intermediate layer formation step of the substrate processing sequence shown in FIG. 4 was not performed. Instead, a thermally nitrided SiN layer having a thickness of 23 Å was formed on the first film, and then a second film formation step was performed to form a plasma nitrided SiN film on the SiO film formed on the substrate surface.

[0167] Then, the etching resistance (processing resistance) of each of the films of evaluation samples 1 to 5 was measured. FIG. 7 shows the depth profile of the wet etching rate (WER) when the film of each evaluation sample was etched using a 1% HF aqueous solution. The vertical axis of FIG. 7 indicates the WER (Å / min) of each film (layer). The horizontal axis of FIG. 7 indicates the total thickness (Å) of each film (layer). The interface between the SiO film and the SiCN layer is located within the range of 20 to 25 (Å) on the horizontal axis.

[0168] 7, it can be seen that the change in WER (change in etching resistance) of the films of evaluation samples 3 and 4 is smaller than the change in WER (change in etching resistance) of the films of evaluation samples 1, 2, and 5. In other words, it can be seen that the width (thickness) of the transition layer of evaluation samples 3 and 4 is smaller than the width (thickness) of the transition layer of evaluation samples 1, 2, and 5. In other words, it was confirmed that the thickness of the transition layer can be made smaller by making the thickness of the intermediate layer relatively large, and that the thickness of the transition layer can be adjusted by adjusting the thickness of intermediate layer 400.

[0169] FIG. 8 shows the evaluation results of the etching resistance (processing resistance) of the films of evaluation samples 6 and 7 on the center side and the outer periphery side of the substrate.

[0170] In evaluation sample 6, a SiCN layer was formed as an intermediate layer on the SiO film formed on the substrate surface by using the substrate processing apparatus in the above-described embodiment, and a SiN film was formed on the SiCN layer by the substrate processing sequence shown in Fig. 4. In evaluation sample 6, the SiCN layer was formed so that the thickness of the SiCN layer was thicker in the outer region than in the central region within the substrate surface.

[0171] In the evaluation sample 7, the substrate processing apparatus according to the above embodiment was used to form a SiCN layer as an intermediate layer on the SiO film formed on the substrate surface, and a SiN film was formed on the SiCN layer by the substrate processing sequence shown in Fig. 4. In the evaluation sample 7, the SiCN layer was formed so that its thickness was uniform within the substrate surface.

[0172] Then, the etching resistance (resistance to processing) of the substrate surface on the central side of the film of Evaluation Sample 6 and Evaluation Sample 7 and the etching resistance (resistance to processing) of the substrate surface on the outer periphery side were measured.

[0173] Fig. 8 is a diagram showing the WER when the films of evaluation samples 6 and 7 were etched using a 1% HF aqueous solution. The vertical axis of Fig. 8 indicates the WER (Å / min) of the film. The horizontal axis of Fig. 8 indicates the total thickness (Å) of each film (layer). The interface with the SiO film exists at a position in the range of 20 to 25 (Å) on the horizontal axis.

[0174] As shown in Fig. 8, the WER of the film with different in-plane thickness distribution in evaluation sample 6 has a smaller difference in WER between the center and outer periphery of the substrate than the WER of the film with uniform in-plane thickness distribution in evaluation sample 7. In other words, it was confirmed that forming an intermediate layer with different in-plane thickness distribution can reduce the difference in WER between the center and outer periphery of the substrate compared to forming an intermediate layer with a uniform in-plane thickness distribution. [Explanation of symbols]

[0175] 200 wafers (substrates)

Claims

1. (a) forming an intermediate layer containing carbon on a first film formed on a substrate; (b) forming a second film containing nitrogen on the intermediate layer using an activated nitrogen-containing gas; In the step (a), the intermediate layer is formed so that the carbon content per unit area contained in the intermediate layer is different between a central region and an outer region within the substrate surface. A method for processing a substrate.

2. 2. The substrate processing method according to claim 1, wherein in (a), the intermediate layer is formed such that a carbon content per unit area of ​​the intermediate layer is greater in the outer region than in the central region.

3. 2. The substrate processing method according to claim 1, wherein in (a), the intermediate layer is formed so that a thickness of the intermediate layer differs between the central region and the outer region.

4. 2. The substrate processing method of claim 1, wherein in (a), the intermediate layer is formed such that a thickness of the intermediate layer is greater in the outer region than in the central region.

5. 5. The substrate processing method of claim 4, wherein in (b), the second film is formed such that a thickness of the second film is greater in the central region than in the outer region.

6. 2. The substrate processing method according to claim 1, wherein in (a), the intermediate layer is formed so that a concentration of carbon contained in the intermediate layer differs between the central region and the outer region.

7. 2. The substrate processing method according to claim 1, wherein in (a), the intermediate layer is formed such that a concentration of carbon contained in the intermediate layer is greater in the outer region than in the central region.

8. The substrate processing method according to claim 1 , wherein in (b), at least a portion of carbon contained in the intermediate layer is desorbed from the intermediate layer.

9. 2. The substrate processing method according to claim 1, wherein in (b), carbon is desorbed from the intermediate layer such that an amount of carbon desorbed per unit area from the intermediate layer differs between the central region and the outer region.

10. In (a), the intermediate layer is formed so that a carbon content per unit area contained in the intermediate layer is greater in the outer region than in the central region; (b) desorbing carbon from the intermediate layer such that an amount of carbon desorbed per unit area from the intermediate layer is greater in the outer region than in the central region; The method for processing a substrate according to claim 1 .

11. After performing (b), a transition layer is formed between the first film and the second film, the transition layer having an etching resistance different from that of either the first film or the second film; 2. The substrate processing method of claim 1, wherein in (a), a distribution of carbon content per unit area contained in the intermediate layer is set so that the thickness of the transition layer has a predetermined distribution within the substrate surface.

12. 2. The substrate processing method of claim 1, wherein in (b), the activated nitrogen-containing gas is supplied from the outer region toward the central region.

13. 2. The substrate processing method according to claim 1, wherein in (b), the nitrogen-containing gas is activated by plasma excitation.

14. 2. The method of claim 1, wherein in (b), the nitrogen-containing gas is thermally activated by heating.

15. 2. The substrate processing method according to claim 1, wherein after (a) is performed, a step of forming a carbon-free nitrogen-containing layer on the intermediate layer without using plasma excitation is not performed until (b) is started.

16. In (b), the nitrogen-containing gas activated by plasma excitation is used; 2. The substrate processing method of claim 1, further comprising: (c) between (a) and (b), a step of forming a nitrogen-containing second intermediate layer on the intermediate layer using a nitrogen-containing gas thermally activated without using plasma excitation, the second intermediate layer having a lower carbon concentration than the carbon concentration contained in the intermediate layer, or being carbon-free.

17. 17. The substrate processing method of claim 16, wherein in (c), the second intermediate layer is formed such that a thickness of the second intermediate layer is greater in the outer region than in the central region.

18. (a) forming an intermediate layer containing carbon on a first film formed on a substrate; (b) forming a second film containing nitrogen on the intermediate layer using an activated nitrogen-containing gas; In the step (a), the intermediate layer is formed so that the carbon content per unit area contained in the intermediate layer is different between a central region and an outer region within the substrate surface. A method for manufacturing a semiconductor device.

19. (a) forming an intermediate layer containing carbon on a first film formed on a substrate; (b) forming a second film containing nitrogen on the intermediate layer using an activated nitrogen-containing gas; (a) forming the intermediate layer such that the carbon content per unit area contained in the intermediate layer differs between a central region and an outer region within the substrate surface; A program for causing a computer to execute the above in a substrate processing apparatus.

20. a carbon-containing gas supply system for supplying a carbon-containing gas to the substrate; a nitrogen-containing gas supply system for supplying a nitrogen-containing gas to the substrate; an activation mechanism for activating the nitrogen-containing gas; (a) supplying the carbon-containing gas to the substrate to form an intermediate layer containing carbon on a first film formed on the substrate; (b) supplying the activated nitrogen-containing gas to the substrate to form a second film containing nitrogen on the intermediate layer; (a) A control unit configured to be able to control the carbon-containing gas supply system, the nitrogen-containing gas supply system, and the activation mechanism so as to form the intermediate layer such that a carbon content per unit area contained in the intermediate layer is different between a central region and an outer region within the substrate surface; The substrate processing apparatus includes:

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