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

Abstract

According to the present invention, a film containing a first element and a second element is formed on a substrate by performing: a first step for forming a first layer containing the first element by performing, a first number of times, a cycle that includes (a-1) a step for supplying a first raw-material gas containing the first element to the substrate, and (a-2) a step for supplying a first reaction gas to the substrate; and a second step for forming a second layer containing the first element and the second element by performing, a second number of times, a cycle that includes (b-1) a step for supplying a second raw-material gas containing the first element and a first halogen element to the substrate, (b-2) a step for supplying a third raw-material gas containing a second halogen element and the second element, which is not contained in the first layer, to the substrate after the supply of the second raw-material gas in step (b-1) has been performed for a first period, and (b-3) a step for supplying a second reaction gas to the substrate after the supply of the third raw-material gas in (b-2) has been performed for a second period.

Description

SUBSTRATE PROCESSING METHOD, SEMICONDUCTOR DEVICE MANUFACTURING APPARATUS, PROGRAM, AND SUBSTRATE PROCESSING APPARATUS

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

[0002] 2. Description of the Related Art One step in the manufacturing process of a semiconductor device is to supply a predetermined gas to a substrate to form a film on the substrate (see, for example, Patent Document 1).

[0003] JP 2016-18907 A

[0004] The present disclosure provides a technique that allows for improved control of the composition ratio of a predetermined element added to a film.

[0005] According to one aspect of the present disclosure, there is provided a technique for forming a film containing the first element and the second element on the substrate by performing a first number of cycles including: (a-1) a step of supplying a first source gas containing a first element to a substrate; and (a-2) a step of supplying a first reactive gas to the substrate, thereby forming a first layer containing the first element; and (b-1) a step of supplying a second source gas containing the first element and a first halogen element to the substrate, and (b-2) a step of supplying a third source gas containing a second halogen element and a second element not contained in the first layer to the substrate after the supply of the second source gas has been carried out for a first period in (b-1), and (b-3) a step of supplying a second reactive gas to the substrate after the supply of the third source gas has been carried out for a second period in (b-2), thereby forming a second layer containing the first element and the second element.

[0006] According to the present disclosure, it is possible to improve the controllability of the composition ratio of a predetermined element added to a film.

[0007] FIG. 1 is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus suitable for use in one embodiment of the present disclosure, showing a processing furnace 202 portion in a vertical cross-sectional view. FIG. 2 is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus suitable for use in one embodiment of the present disclosure, showing the processing furnace 202 portion in a cross-sectional view taken along line A-A in FIG. 1. FIG. 3 is a schematic configuration diagram of a controller 121 of a substrate processing apparatus suitable for use in one embodiment of the present disclosure, showing a control system of the controller 121 in a block diagram. FIG. 4 is a diagram showing a processing sequence in one embodiment of the present disclosure. FIG. 5 is a diagram showing an example of a cross-sectional structure of a NAND memory cell. FIG. 6(a) is a diagram showing a processing sequence in a first modification of the present disclosure. FIG. 6(b) is a diagram showing a processing sequence in a second modification of the present disclosure. FIG. 7(a) is a diagram showing an example of a processing sequence in a third modification of the present disclosure. FIG. 7(b) is a diagram showing another example of a processing sequence in the third modification of the present disclosure. FIG. 8(a) is a diagram showing a processing sequence in a fourth modification of the present disclosure. Fig. 8(b) is a diagram showing a processing sequence according to Modification 5 of the present disclosure. Fig. 8(c) is a diagram showing a processing sequence according to Modification 6 of the present disclosure. Fig. 9 is a diagram illustrating a charge trap film formed by the processing sequence according to Modification 1 of the present disclosure.

[0008] <One Aspect of the Present Disclosure> One aspect of the present disclosure will be described below, mainly with reference to Figures 1 to 5. Note that all drawings used in the following description are schematic, and the dimensional relationships, ratios, etc. of elements shown in the drawings do not necessarily match those of reality. Furthermore, the dimensional relationships, ratios, etc. of elements between multiple drawings do not necessarily match.

[0009] (1) Configuration of the Substrate Processing Apparatus As shown in Fig. 1, the processing furnace 202 has a heater 207 as a temperature regulator (heating unit). The heater 207 is cylindrical and is installed vertically by being supported by a holding plate. The heater 207 also functions as an activation mechanism (excitation unit) that activates (excites) gases by heat.

[0010] A reaction tube 203 is disposed concentrically inside the heater 207. A manifold 209 is disposed concentrically below the reaction tube 203. The upper end of the manifold 209 engages with the lower end of the reaction tube 203 and is configured to support the reaction tube 203. An O-ring 220a serving as a sealing member is provided between the manifold 209 and the reaction tube 203. The reaction tube 203 and the manifold 209 mainly constitute a processing vessel (reaction vessel). A processing chamber 201 is formed in a cylindrical hollow portion of the processing vessel. The processing chamber 201 is configured to be able to accommodate wafers 200 as substrates. The wafers 200 are processed in this processing chamber 201.

[0011] Nozzles 249a and 249b serving as a first supply unit and a second supply unit are provided in the processing chamber 201 so as to penetrate the sidewall of the manifold 209, respectively. The nozzles 249a and 249b are also referred to as a first nozzle and a second nozzle, respectively. Gas supply pipes 232a and 232b are connected to the nozzles 249a and 249b, respectively. The nozzles 249a and 249b are different nozzles, and the nozzles 249a and 249b are provided adjacent to each other.

[0012] Gas supply pipes 232a and 232b are respectively provided with mass flow controllers (MFCs) 241a and 241b, which are flow rate controllers (flow rate control units), and valves 243a and 243b, which are on-off valves, in order from the upstream side of the gas flow. Gas supply pipes 232c to 232e and 232g are respectively connected to gas supply pipe 232a downstream of valve 243a. Gas supply pipes 232f and 232h are respectively connected to gas supply pipe 232b downstream of valve 243b. Gas supply pipes 232c to 232h are respectively provided with MFCs 241c to 241h and valves 243c to 243h in order from the upstream side of the gas flow.

[0013] As shown in FIG. 2 , the nozzles 249 a and 249 b are provided in a circular space between the inner wall of the reaction tube 203 and the wafers 200 in a plan view, extending from the bottom to the top of the inner wall of the reaction tube 203 and rising upward in the arrangement direction of the wafers 200. That is, the nozzles 249 a and 249 b are provided in regions horizontally surrounding the wafer arrangement region on the sides of the wafer arrangement region where the wafers 200 are arranged, extending along the wafer arrangement region. Gas supply holes 250 a and 250 b for supplying gas are provided on the side surfaces of the nozzles 249 a and 249 b, respectively. The gas supply holes 250 a and 250 b are each open toward the center of the wafer 200 in a plan view, allowing gas to be supplied toward the wafer 200. A plurality of gas supply holes 250 a and 250 b are provided from the bottom to the top of the reaction tube 203.

[0014] A first source gas containing a first element is supplied from the gas supply pipe 232a into the processing chamber 201 via the MFC 241a, the valve 243a, and the nozzle 249a.

[0015] A first reaction gas is supplied from the gas supply pipe 232b into the processing chamber 201 via an MFC 241b, a valve 243b, and a nozzle 249b.

[0016] A second source gas containing a first element and a first halogen element is supplied from the gas supply pipe 232c into the processing chamber 201 via the MFC 241c, the valve 243c, the gas supply pipe 232a, and the nozzle 249a.

[0017] A third source gas containing a second halogen element and a predetermined second element is supplied from the gas supply pipe 232d into the processing chamber 201 via the MFC 241d, the valve 243d, the gas supply pipe 232a, and the nozzle 249a.

[0018] A fourth source gas containing the first element, the third halogen element, and hydrogen (H) is supplied from the gas supply pipe 232e into the processing chamber 201 via the MFC 241e, the valve 243e, the gas supply pipe 232a, and the nozzle 249a.

[0019] A second reaction gas is supplied from the gas supply pipe 232f into the processing chamber 201 via the MFC 241f, the valve 243f, the gas supply pipe 232b, and the nozzle 249b.

[0020] Inert gas is supplied from the gas supply pipes 232g and 232h into the processing chamber 201 via the MFCs 241g and 241h, the valves 243g and 243h, the gas supply pipes 232a and 232b, and the nozzles 249a and 249b, respectively. The inert gas acts as a purge gas, a carrier gas, a dilution gas, etc.

[0021] The first precursor gas supply system mainly includes the gas supply pipe 232a, the MFC 241a, and the valve 243a. The first reactive gas supply system mainly includes the gas supply pipe 232b, the MFC 241b, and the valve 243b. The second precursor gas supply system mainly includes the gas supply pipe 232c, the MFC 241c, and the valve 243c. The third precursor gas supply system mainly includes the gas supply pipe 232d, the MFC 241d, and the valve 243d. The fourth precursor gas supply system mainly includes the gas supply pipe 232e, the MFC 241e, and the valve 243e. The second reactive gas supply system mainly includes the gas supply pipe 232f, the MFC 241f, and the valve 243f. An inert gas supply system is mainly composed of the gas supply pipes 232g and 232h, the MFCs 241g and 241h, and the valves 243g and 243h. A gas supply system is composed of all or at least some of the various supply systems described above. Nozzles connected to the gas supply pipes constituting the various supply systems described above may also be included in the supply systems.

[0022] Any or all of the various supply systems described above may be configured as an integrated supply system 248 in which the valves 243a to 243h, the MFCs 241a to 241h, and the like are integrated.

[0023] An exhaust port 231a for exhausting the atmosphere inside the processing chamber 201 is provided at the bottom of the sidewall of the reaction tube 203. An exhaust pipe 231 is connected to the exhaust port 231a. A vacuum pump 246 serving as a vacuum exhaust device is connected to the exhaust pipe 231 via a pressure sensor 245 serving as a pressure detector (pressure detection unit) for detecting the pressure inside the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 serving as a pressure regulator (pressure adjustment unit). The APC valve 244 can evacuate and stop the evacuation of the processing chamber 201 by opening and closing the valve while the vacuum pump 246 is operating. Furthermore, while the vacuum pump 246 is operating, the pressure inside the processing chamber 201 can be adjusted by adjusting the valve opening based on pressure information detected by the pressure sensor 245. An exhaust system is mainly composed of the exhaust pipe 231, the APC valve 244, and the pressure sensor 245. A vacuum pump 246 may be included in the exhaust system.

[0024] A seal cap 219 serving as a furnace port cover is provided below the manifold 209, and is capable of airtightly closing the lower end opening of the manifold 209 via an O-ring 220b. A rotation mechanism 267 for rotating a boat 217 (described later) is provided below the seal cap 219. A rotation shaft 255 of the rotation mechanism 267 passes through the seal cap 219 and is connected to the boat 217. The rotation mechanism 267 is configured to rotate the wafers 200 by rotating the boat 217. The seal cap 219 is configured to be raised and lowered vertically by a boat elevator 115 serving as an elevating mechanism installed outside the reaction tube 203. The boat elevator 115 is configured as a transfer device (transfer mechanism) that raises and lowers the seal cap 219 to load and unload (transfer) the wafers 200 into and out of the process chamber 201.

[0025] A shutter 219s serving as a furnace port cover is provided below the manifold 209 and capable of airtightly closing the lower end opening of the manifold 209 via an O-ring 220c when the seal cap 219 is lowered and the boat 217 is carried out of the processing chamber 201. The opening and closing operation (lifting and lowering operation, rotating operation, etc.) of the shutter 219s is controlled by a shutter opening and closing mechanism 115s.

[0026] The boat 217 as a substrate support is configured to support a plurality of wafers 200, for example, 25 to 200 wafers 200, in multiple stages, in a horizontal position, with their centers aligned in the vertical direction, i.e., arranged at intervals. Heat insulating plates 218 are supported in multiple stages at the bottom of the boat 217.

[0027] A temperature sensor 263 serving as a temperature detector is installed inside 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 inside the processing chamber 201 becomes a desired one. The temperature sensor 263 is installed along the inner wall of the reaction tube 203.

[0028] 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 exchange data with the CPU 121a via an internal bus 121e. An input / output device 122, such as a touch panel, is connected to the controller 121. An external storage device 123 can also 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 below may be performed using one control unit or multiple control units. Furthermore, the multiple control units may be configured as a control system connected to each other via a wired or wireless communication network, and the control for carrying out the processing sequence described below may be performed by the entire control system. When the term "control unit" is used in this specification, it may include not only one control unit but also multiple control units or a control system configured by multiple control units.

[0029] The storage device 121c is composed of, for example, a flash memory, a hard disk drive (HDD), a solid state drive (SSD), etc. Control programs for controlling the operation of the substrate processing apparatus, process recipes describing procedures and conditions for substrate processing (described later), etc., are readably recorded and stored in the storage device 121c. The process recipe is a combination of procedures for substrate processing (described later) that are executed by the controller 121 in the substrate processing apparatus to obtain a predetermined result, and functions as a program. Hereinafter, the process recipes, control programs, etc. are collectively referred to simply as programs. The process recipes are also simply referred to as recipes. In this specification, the term "program" may refer to a recipe alone, a control program alone, or both. The RAM 121b is configured as a memory area (work area) for temporarily storing programs, data, etc. read by the CPU 121a.

[0030] The I / O port 121d is connected to the above-mentioned MFCs 241a to 241h, valves 243a to 243h, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotation mechanism 267, boat elevator 115, shutter opening / closing mechanism 115s, etc.

[0031] The CPU 121a is configured to read and execute a control program from the storage device 121c, and to read a recipe from the storage device 121c in response to an input of an operation command from the input / output device 122. The CPU 121a is configured to control, in accordance with the contents of the read recipe, the flow rate adjustment operation of various substances (various gases) by the MFCs 241a to 241h, the opening and closing operation of the valves 243a to 243h, 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 lifting and lowering operation of the boat 217 by the boat elevator 115, the opening and closing operation of the shutter 219s by the shutter opening and closing mechanism 115s, and the like.

[0032] The controller 121 can be configured by installing the above-mentioned program recorded and stored in the external storage device 123 into a computer. The external storage device 123 includes, for example, a magnetic disk such as an HDD, an optical disk such as a CD, a magneto-optical disk such as an MO, and a semiconductor memory such as a USB memory or an SSD. The storage device 121c and the external storage device 123 are configured as computer-readable recording media. Hereinafter, these will be collectively referred to as recording media. When the term recording medium is used in this specification, it may include only the storage device 121c alone, only the external storage device 123 alone, or both. Note that 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.

[0033] (2) Substrate Processing Step An example of a processing sequence for forming a film on the surface of a wafer 200 as a substrate, as one step in the manufacturing process of a semiconductor device, using the substrate processing apparatus described above will be described mainly 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.

[0034] In the processing sequence of this aspect, a film containing the first element and the second element is formed on the wafer 200 by performing a first number of times (m times, m being an integer of 1 or 2 or more) a cycle including: Step A1 supplying a first source gas containing a first element to the wafer 200; Step A2 supplying a first reactive gas to the wafer 200; a second number of times (n times, n being an integer of 1 or 2 or more) a cycle including: Step B1 supplying a second source gas containing the first element and a first halogen element to the wafer 200; Step B2 supplying a third source gas containing the second halogen element and a second element not contained in the first layer to the wafer 200 after the supply of the second source gas has been carried out for a first period in Step B1; and Step B3 supplying a second reactive gas to the wafer 200 after the supply of the third source gas has been carried out for a second period in Step B2;

[0035] In this embodiment, an example of forming a charge trap film (charge trap film) of a nonvolatile memory cell as a film containing a first element and a second element (hereinafter, sometimes simply referred to as a "film") will be described. The charge trap film is, for example, an ONO film constituting a NAND flash memory, i.e., a SiN film among the insulating films composed of three layers of a SiO film / SiN film / SiO film (see FIG. 5). In this embodiment, as an example, a case where a SiN film is formed as the film will be described.

[0036] 4, the first source gas, the second source gas, and the third source gas are denoted as 1, 2, and 3, respectively, and the first reactive gas and the second reactive gas are denoted as i and ii, respectively. Furthermore, P in FIG. 4 indicates that the inside of the processing chamber 201 is purged. These points are the same in FIGS. 6A to 8C.

[0037] In this specification, the term "wafer" may refer to the wafer itself or a laminate of the wafer and a predetermined layer or film formed on its surface. In this specification, the term "surface of a wafer" may refer to the surface of the wafer itself or the surface of a predetermined layer or the like formed on the wafer. In this specification, the phrase "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. In this specification, the term "substrate" is also synonymous with the term "wafer".

[0038] The term "layer" as used herein includes at least one of a continuous layer and a discontinuous layer. For example, the first layer and the second layer described below may include a continuous layer, a discontinuous layer, or both.

[0039] In this specification, when we talk about the first source gas, the second source gas, etc., adsorbing to or reacting with the surface of the wafer 200, it may include not only the case where they adsorb to or react with the wafer surface without being decomposed, but also the case where they decompose or an intermediate produced by the detachment of their ligands adsorbs to or reacts with the surface of the wafer 200.

[0040] (Wafer Charging and Boat Loading) When a plurality of wafers 200 are loaded into the boat 217, the shutter 219s is moved to open the lower end opening of the manifold 209. Thereafter, the boat 217 supporting the plurality of wafers 200 is lifted by the boat elevator 115 and carried into the processing chamber 201.

[0041] (Pressure Adjustment and Temperature Adjustment) After the boat loading is completed, the inside of the processing chamber 201, i.e., the processing space in which the wafers 200 are present, is evacuated (reduced pressure exhausted) by the vacuum pump 246 so as to reach the desired pressure (vacuum level). At this time, the pressure inside the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 244 is feedback-controlled based on this measured pressure information (pressure adjustment). Furthermore, the wafers 200 in the processing chamber 201 are heated by the heater 207 so as to reach the desired processing temperature. At this time, the power supply to the heater 207 is feedback-controlled based on temperature information detected by the temperature sensor 263 so as to achieve the desired temperature distribution inside the processing chamber 201 (temperature adjustment). Furthermore, the rotation mechanism 267 starts to rotate the wafers 200. The evacuation inside the processing chamber 201 and the heating and rotation of the wafers 200 are all continued at least until the processing of the wafers 200 is completed.

[0042] (First Step (First Processing)) Thereafter, steps A1 and A2 are executed in sequence.

[0043] [Step A1] In step A1, a first source gas is supplied to the wafer 200 in the processing chamber 201.

[0044] Specifically, the valve 243a is opened to allow a first source gas to flow into the gas supply pipe 232a. The flow rate of the first source gas is adjusted by the MFC 241a, and the first source gas is supplied into the processing chamber 201 via the nozzle 249a and exhausted from the exhaust port 231a. At this time, the first source gas is supplied to the wafers 200. At this time, the valves 243g and 243h may be opened to supply an inert gas into the processing chamber 201 via the nozzles 249a and 249b, respectively.

[0045] Examples of the processing conditions in this step include: processing temperature: 350 to 800° C., preferably 500 to 700° C. processing pressure: 10 to 1333 Pa, preferably 10 to 133 Pa first source gas supply flow rate: 0.1 to 3 slm, preferably 0.1 to 0.5 slm first source gas supply time: 1 to 180 seconds, preferably 10 to 80 seconds inert gas supply flow rate (per gas supply pipe): 0 to 20 slm

[0046] In this specification, when a numerical range such as "350 to 800°C" is expressed, both the lower limit and the upper limit are included in the range. For example, "350 to 800°C" means "350°C or higher and 800°C or lower." The same applies to other numerical ranges. In this specification, the term "processing temperature" refers to the temperature of the wafer 200 or the temperature inside the processing chamber 201, and the term "processing pressure" refers to the pressure inside the processing chamber 201, in other words, the pressure in the space in which the wafer 200 is present. Furthermore, the term "processing time" refers to the time the processing continues. Furthermore, when the supply flow rate includes 0 slm, 0 slm means that the substance (gas) is not supplied. These terms also apply to the following description.

[0047] By supplying, for example, a chlorosilane-based gas as the first source gas to the wafer 200 under the above-described processing conditions, a silicon (Si)-containing layer containing chlorine (Cl) is formed on the surface of the wafer 200. The Si-containing layer containing Cl is formed by physical adsorption or chemical adsorption of molecules of the chlorosilane-based gas, or physical adsorption or chemical adsorption of molecules of a substance formed by decomposition of a portion of the chlorosilane-based gas, on the outermost surface of the wafer 200. The Si-containing layer containing Cl may be an adsorption layer (physical adsorption layer or chemical adsorption layer) of molecules of the chlorosilane-based gas or molecules of a substance formed by decomposition of a portion of the chlorosilane-based gas. In this specification, the Si-containing layer containing Cl is also simply referred to as a Si-containing layer. The Si-containing layer formed in this step is also referred to as a first Si-containing layer.

[0048] After the first Si-containing layer is formed, the valve 243a is closed to stop the supply of the first source gas into the processing chamber 201. Then, the processing chamber 201 is evacuated to remove (purge) any gas remaining in the processing chamber 201. At this time, the valves 243g and 243h are opened, and an inert gas is supplied into the processing chamber 201 through the nozzles 249a and 249b. The inert gas acts as a purge gas.

[0049] The first source gas may be, for example, a silane-based gas containing Si as the first element, which is the main element constituting the film formed on the wafer 200. The silane-based gas may be, for example, a gas containing Si and a halogen element, i.e., a halosilane-based gas. Halogen elements include Cl, fluorine (F), bromine (Br), iodine (I), and the like. The halosilane-based gas may be, for example, the above-mentioned chlorosilane-based gas containing Si and Cl.

[0050] The first source gas is, for example, tetrachlorosilane (SiCl ４ ) gas, hexachlorodisilane gas (Si ２ Cl ６ ) gas, octachlorotrisilane (Si ３ Cl ８ ) gas or other non-H-containing chlorosilane gases can be used.

[0051] The first source gas is, for example, monochlorosilane (SiH ３ Cl) gas, dichlorosilane (SiH ２ Cl ２ ) gas, trichlorosilane (SiHCl ３ ) gas or other H-containing chlorosilane gases can be used.

[0052] The first source gas may be, for example, tetrafluorosilane (SiF ４ ) gas, hexafluorodisilane (Si ２ F ６ ) gas, or tetrabromosilane (SiBr ４ ) gas, hexabromodisilane (Si ２ Br ６ ) gas, or tetraiodosilane (SiI ４ ) gas, hexaiododisilane (Si ２ I ６ It is also possible to use a non-H-containing iodosilane gas such as silane-based silane.

[0053] The first source gas may be a chlorosilane-based gas or, for example, difluorosilane (SiH ２ F ２) gas, trifluorosilane (SiHF ３ ) and dibromosilane (SiH ２ Br ２ ) gas, tribromosilane (SiHBr ３ ) gas, diiodosilane (SiH ２ I ２ ) gas, triiodosilane (SiHI ３ It is also possible to use an H-containing iodosilane gas such as silane-based silane gas.

[0054] The first source gas may be, for example, tetrakis(dimethylamino)silane (Si[N(CH ３ ) ２ ] ４ ) gas, tris(dimethylamino)silane (Si[N(CH ３ ) ２ ] ３ H) gas, bis(diethylamino)silane (Si[N(C ２ H ５ ) ２ ] ２ H ２ ) gas, bis(tert-butylamino)silane (SiH ２ [NH(C ４ H ９ )] ２ ) gas, (diisopropylamino)silane (SiH ３ [N(C ３ H ７ ) ２ An aminosilane-based gas such as tetraethoxysilane (Si(OC)] can also be used as the first source gas. ２ H ５ ) ４ Alternatively, organic silane gases not containing amino groups, such as silane gases, may be used.

[0055] As the first source gas, one or more of these can be used.

[0056] The inert gas is nitrogen (N ２Inert gases that can be used include rare gases such as argon (Ar) gas, helium (He) gas, neon (Ne) gas, and xenon (Xe) gas. One or more of these gases can be used as the inert gas. This also applies to the steps described below.

[0057] [Step A2] After step A1 is completed, a first reaction gas is supplied to the wafers 200 in the processing chamber 201, that is, to the first Si-containing layer formed on the wafers 200.

[0058] Specifically, valve 243b is opened to allow a first reaction gas to flow into gas supply pipe 232b. The flow rate of the first reaction gas is adjusted by MFC 241b, and the first reaction gas is supplied into processing chamber 201 via nozzle 249b and exhausted from exhaust port 231a. At this time, the first reaction gas is supplied to wafer 200. At this time, valves 243g and 243h may be opened to supply an inert gas into processing chamber 201 via nozzles 249a and 249b, respectively.

[0059] Examples of processing conditions in this step include: processing pressure: 10 to 3750 Pa, preferably 10 to 1333 Pa; first reactant gas supply flow rate: 1 to 10 slm, preferably 3 to 6 slm; first reactant gas supply time: 1 to 180 seconds, preferably 10 to 60 seconds. Other processing conditions can be the same as those in step A1.

[0060] Supplying the first reactive gas to the wafer 200 under the above-described conditions modifies at least a portion of the first Si-containing layer formed on the wafer 200. When, for example, a hydrogen nitride gas containing nitrogen (N) and H as a third element is used as the first reactive gas, at least a portion of the first Si-containing layer formed on the wafer 200 is nitrided, and a silicon nitride layer (SiN layer) containing Si and N as a third element is formed on the outermost surface of the wafer 200.

[0061] After the SiN layer is formed, the valve 243b is closed to stop the supply of the first reaction gas into the processing chamber 201. Then, gases remaining in the processing chamber 201 are removed from the processing chamber 201 by a processing procedure similar to the purging in step A1.

[0062] The first reaction gas may be, for example, a nitriding gas (nitriding agent). For example, ammonia (NH ３ ) gas, diazene (N ２ H ２ ) gas, hydrazine (N ２ H ４ ) gas, N ３ H ８ The first reactive gas may be one or more of these gases.

[0063] [Performance Predetermined Number of Times] By performing a cycle of the above-described steps A1 and A2 asynchronously, i.e., without synchronization, a first number of times (m times, where m is an integer of 1 or 2 or more, preferably an integer of 1 to 10), a SiN layer can be formed as a first layer on the surface of wafer 200. The above-described cycle is preferably repeated multiple times. That is, it is preferable to make the thickness of the SiN layer formed per cycle thinner than the desired film thickness, and to repeat the above-described cycle multiple times until the film thickness of the first layer formed by stacking SiN layers reaches the desired film thickness.

[0064] (Second Step (Second Processing)) After that, steps B1 to B3 are executed in sequence.

[0065] [Step B1] In step B1, a second source gas containing a first element and a first halogen element is supplied to the wafer 200 in the processing chamber 201, that is, to the first layer formed on the wafer 200.

[0066] Specifically, the valve 243c is opened to allow the second source gas to flow into the gas supply pipe 232c. The flow rate of the second source gas is adjusted by the MFC 241c, and the second source gas is supplied into the processing chamber 201 via the nozzle 249a and exhausted from the exhaust port 231a. At this time, the second source gas is supplied to the wafers 200. At this time, the valves 243g and 243h may be opened to supply an inert gas into the processing chamber 201 via the nozzles 249a and 249b, respectively.

[0067] Examples of processing conditions for this step include: second source gas supply flow rate: 0.1 to 3 slm, preferably 0.1 to 0.5 slm; and second source gas supply time (first period): 1 to 180 seconds, preferably 10 to 30 seconds. Other processing conditions can be the same as those for step A1. However, in order to adjust the composition ratio of the second element contained (doped) in the second layer formed in this process, the processing conditions for this step may be different from those for step A1. For example, the composition ratio of the second element may be increased by making the supply flow rate of the second source gas smaller than the supply flow rate of the first source gas. Alternatively, the composition ratio of the second element may be increased by making the supply time of the second source gas shorter than the supply time of the first source gas.

[0068] By supplying the wafer 200 with a second source gas containing, for example, Si as a first element and a first halogen element under the above-described processing conditions, a Si-containing layer containing Si and having a surface terminated with the first halogen element can be formed on the SiN layer as the first layer formed on the wafer 200. In this specification, the termination of the first halogen element is also referred to as a first halogen termination. The Si-containing layer formed in this step is also referred to as a second Si-containing layer.

[0069] After the second source gas is supplied for a first period and a second Si-containing layer is formed, the valve 243c is closed to stop the supply of the second source gas into the processing chamber 201. Then, gases remaining in the processing chamber 201 are removed from the processing chamber 201 by a procedure similar to the purging in step A1. However, the purging step of the processing chamber 201 between step B1 and step B2 can be omitted. That is, step B1 and step B2 can be performed consecutively.

[0070] The second source gas may be, for example, a halosilane-based gas containing Si as a first element, which is a main element constituting the film formed on the wafer 200, and a first halogen element. The first halogen element includes Cl, F, Br, I, etc. The halosilane-based gas may be, for example, a chlorosilane-based gas containing Si and Cl.

[0071] The second source gas may be, for example, a gas containing one or more of the halosilane gases listed as examples of the first source gas. The second source gas is preferably the same as the first source gas, but may be a gas different from the first source gas. However, the second source gas is preferably a non-H-containing gas.

[0072] [Step B2] In step B2, a third source gas containing a second halogen element and a second element not contained in the first layer is supplied to the wafer 200 in the processing chamber 201, i.e., the second Si-containing layer on the wafer 200.

[0073] Specifically, the valve 243d is opened to allow the third source gas to flow into the gas supply pipe 232d. The flow rate of the third source gas is adjusted by the MFC 241d, and the third source gas is supplied into the processing chamber 201 via the nozzle 249a and exhausted from the exhaust port 231a. At this time, the third source gas is supplied to the wafers 200. At this time, the valves 243g and 243h may be opened to supply an inert gas into the processing chamber 201 via the nozzles 249a and 249b, respectively.

[0074] Examples of processing conditions in this step include: supply flow rate of third source gas: 0.05 to 6 slm, preferably 0.5 to 2 slm supply time of third source gas (second period): 2 to 60 seconds, preferably 4 to 30 seconds Other processing conditions can be the same as those in step A1.

[0075] By supplying the wafer 200 with a third source gas containing a second halogen element and a predetermined second element under the above-described processing conditions, titanium (Ti) as the second element can be adsorbed to regions (adsorption sites) on the second Si-containing layer where the first halogen termination is not formed, thereby forming a termination of the second halogen element. In this manner, the second Si-containing layer can be doped with, for example, Ti. This allows the second Si-containing layer formed on the wafer 200 in step B1 to be converted into a Ti-doped second Si-containing layer. In this specification, the termination of the second halogen element is also referred to as a second halogen termination.

[0076] The third source gas is supplied for a second period, and after a second Si-containing layer doped with Ti is formed, the valve 243d is closed to stop the supply of the third source gas into the processing chamber 201. Then, gases remaining in the processing chamber 201 are removed from the processing chamber 201 by a processing procedure similar to the purging in step A1.

[0077] The third source gas may be, for example, a halide (titanium halide) gas containing a second halogen element and Ti as the second element. The second halogen element includes Cl, F, Br, I, etc. The second halogen element may be the same element as the first halogen element or a different element. The second element is an element different from the first element. The third source gas is a gas different from the first source gas and the second source gas.

[0078] The third source gas may be, for example, titanium tetrachloride (TiCl ４ ) gas, titanium tetrafluoride (TiF ４ ) gas, tetrabromotitanium (TiBr ４ ) gas, titanium tetraiodide (TiI ４ ) gas, or other H-free titanium halide gases can be used.

[0079] The third source gas may be, for example, titanium monochloride (TiH ３ Cl) gas, titanium dioxide (TiH ２ F ２ ) gas, dibromotitanium (TiH ２ Br２ ) gas, titanium diiodide (TiH ２ I ２ ) gas or other H-containing titanium halide gas can be used.

[0080] The third source gas may be one or more of these. The third source gas is preferably a non-H-containing gas.

[0081] [Step B3] In step B3, a second reaction gas is supplied to the wafers 200 in the processing chamber 201, that is, to the second Si-containing layer doped with Ti on the wafers 200.

[0082] Specifically, the valve 243f is opened to allow the second reactive gas to flow into the gas supply pipe 232f. The flow rate of the second reactive gas is adjusted by the MFC 241f, and the second reactive gas is supplied into the processing chamber 201 via the nozzle 249b and exhausted from the exhaust port 231a. At this time, the second reactive gas is supplied to the wafer 200. At this time, the valves 243g and 243h may be opened to supply an inert gas into the processing chamber 201 via the nozzles 249a and 249b, respectively.

[0083] Examples of processing conditions in this step include: processing pressure: 10 to 3750 Pa, preferably 10 to 1333 Pa; second reactant gas supply flow rate: 1 to 10 slm, preferably 3 to 6 slm; second reactant gas supply time: 1 to 180 seconds, preferably 10 to 60 seconds. Other processing conditions can be the same as those in step A1.

[0084] Supplying the second reactive gas to the wafer 200 under the above-described conditions modifies at least a portion of the Ti-doped second Si-containing layer formed on the wafer 200. When, for example, a hydrogen nitride gas containing N and H as a third element is used as the second reactive gas, as with the first reactive gas, at least a portion of the Ti-doped second Si-containing layer formed on the wafer 200 is nitrided, and a Ti-doped SiN layer containing Si and N as a third element is formed.

[0085] After the Ti-doped SiN layer is formed, the valve 243f is closed to stop the supply of the second reaction gas into the processing chamber 201. Then, gases remaining in the processing chamber 201 are removed from the processing chamber 201 by a processing procedure similar to the purging in step A1.

[0086] The second reactive gas may be, for example, a gas containing one or more of the gases listed as examples of the first reactive gas. The second reactive gas is preferably the same as the first reactive gas, but may also be a gas different from the first reactive gas. The second reactive gas is preferably a gas that reacts with the first halogen termination and the second halogen termination.

[0087] [Performance Predetermined Number of Times] By performing the above-described cycle of steps B1 to B3 asynchronously, i.e., without synchronization, a second number of times (n times, where n is an integer of 1 or 2 or more, preferably an integer of 1 to 10), it is possible to form, for example, a Ti-doped SiN layer as a second layer on a SiN layer as a first layer. The above-described cycle is preferably repeated multiple times. That is, it is preferable to make the thickness of the Ti-doped SiN layer formed per cycle thinner than the desired film thickness, and to repeat the above-described cycle multiple times until the film thickness of the second layer formed by stacking the Ti-doped SiN layers reaches the desired film thickness.

[0088] By performing a cycle including the above-described first and second steps a predetermined number of times (p times, where p is an integer of 1 or 2 or greater, preferably a third number of times equal to an integer of 2 or greater), a Ti-doped SiN film (hereinafter also simply referred to as a "SiN film") can be formed on the wafer 200. The Ti-doped SiN film can also be referred to as a film containing a first element and a third element doped with a second element. In this embodiment, it is preferable to make the thickness of the SiN film formed per cycle thinner than the desired film thickness, and to repeat the above-described cycle multiple times until the thickness of the SiN film formed by stacking the SiN films reaches the desired thickness.

[0089] It is preferable that the ratio (i.e., n / m) of the second number of times (n times) in the second step to the first number of times (m times) in the first step be set (i.e., selected) so that the composition ratio of Ti in the SiN film becomes a predetermined ratio.

[0090] The supply amount of the second source gas in step B1 is preferably set so that the Ti composition ratio in the Ti-doped SiN layer is a predetermined ratio. Specifically, at least one of the supply flow rate of the second source gas and the supply time of the second source gas in step B1 is preferably set so that the Ti composition ratio in the Ti-doped SiN layer is a predetermined ratio.

[0091] The thickness of the SiN layer as the first layer is preferably a thickness (less than or equal to the thickness) that allows the Ti contained in the Ti-doped SiN layer as the second layer to diffuse throughout the entire thickness direction of the adjacent SiN layer.

[0092] (After-Purge and Return to Atmospheric Pressure) After step B3 is completed, an inert gas serving as a purge gas is supplied into the processing chamber 201 from each of the nozzles 249a and 249b, and is exhausted from the exhaust port 231a. This purges the processing chamber 201, and gases and reaction by-products remaining in the processing chamber 201 are removed from the processing chamber 201. 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 atmospheric pressure.

[0093] (Boat Unloading and Wafer Discharge) Thereafter, the seal cap 219 is lowered by the boat elevator 115, and the lower end of the manifold 209 is opened. Then, the processed wafers 200, supported by the boat 217, are unloaded from the lower end of the manifold 209 to the outside of the reaction tube 203. After the boat unloading, the opening at the lower end of the manifold 209 is sealed by the shutter 219s. After being unloaded to the outside of the reaction tube 203, the processed wafers 200 are taken out of the boat 217.

[0094] (3) Effects of this Aspect According to this aspect, one or more of the following effects can be obtained.

[0095] (a) By performing a cycle including a first process that does not include a step of supplying a gas containing a second element and a second process that includes a step of supplying a gas containing a second element, it is possible to improve the controllability of the composition ratio of the second element doped into the film (i.e., the composition ratio of the second element to all elements constituting the film). In particular, in a region where the composition ratio of the doped second element is low (e.g., less than 5 atomic %, preferably less than 1 atomic %), it is possible to easily finely adjust the composition ratio of the second element. This makes it easier to obtain desired film characteristics, such as desired charge trap characteristics.

[0096] (b) By performing a cycle including the first and second steps two or more times, it is possible to further improve the controllability of the composition ratio of the second element added to the film.

[0097] (c) In step B1, by supplying the second source gas, which is a non-H-containing gas, it is possible to reduce H terminations (adsorption sites) on the surface of the second Si-containing layer before the supply of the third source gas, where the third source gas can be adsorbed. This makes it possible to suppress the second element contained in the third source gas from being adsorbed onto the second Si-containing layer. As a result, it is possible to control the composition ratio of the second element in the film to be low.

[0098] (d) In step B2, by supplying a third source gas that is a non-H-containing gas, i.e., a gas that does not react with halogen termination, it is possible to suppress desorption of the first halogen element from the second Si-containing layer on which the first halogen termination is formed after supplying the second source gas. This suppresses the second element contained in the third source gas from being adsorbed (doped) into the second Si-containing layer. As a result, it is possible to control the composition ratio of the second element in the film to be low.

[0099] (e) In step B3, by supplying a second reactive gas that reacts with both the first and second halogen terminations, the first and second halogen elements bonded to the first element can be desorbed from the second Si-containing layer doped with the second element. As a result, impurities such as the first and second halogen elements in the film can be reduced. Furthermore, by desorbing the first and second halogen elements bonded to the first element from the second Si-containing layer doped with the second element and forming dangling bonds of the first element, adsorption of the second source gas can be promoted in step B1 of the next cycle. As a result, film formation can be promoted.

[0100] (f) By using the same first and second source gases, the composition of the first layer and the composition of the second layer can be made closer to each other except for the second element, i.e., the film characteristics can be made closer to uniformity in the thickness direction except for the second element.

[0101] (g) By using the same first and second reactant gases, the composition of the first layer and the composition of the second layer can be made closer to each other except for the second element, i.e., the film characteristics can be made closer to uniformity in the thickness direction except for the second element.

[0102] (h) The ratio of the second number of times in the second step to the first number of times in the first step is set so that the composition ratio of the second element in the film is a predetermined ratio. By adjusting the ratio of the number of stacked first layers not containing the second element to the number of stacked second layers containing the second element, the composition ratio of the second element in the film can be controlled to a desired value.

[0103] (i) The supply amount of the second source gas in step B1 is set so that the composition ratio of the second element in the second layer is a predetermined ratio. For example, by adjusting the supply amount of the second source gas in step B1, the ratio of adsorption sites on the wafer 200 surface that can adsorb the third source gas (specifically, the second element) (i.e., not terminated with the first halogen) can be adjusted. This allows the composition ratio of the second element in the second layer to be controlled. Specifically, for example, in step B1, the ratio of adsorption sites for the second element on the wafer 200 surface can be increased by at least one of reducing the supply flow rate of the second source gas or shortening the supply time of the second source gas. This increases the amount of adsorption of the second element and increases the composition ratio of the second element in the film. Also, for example, in step B1, the ratio of adsorption sites for the second element on the wafer 200 surface can be reduced by at least one of increasing the supply flow rate of the second source gas or lengthening the supply time of the second source gas. This reduces the amount of the second element adsorbed, and makes it possible to reduce the composition ratio of the second element in the film.

[0104] (j) The thickness of the first layer is set to a thickness (or less) that allows the second element contained in the second layer to diffuse throughout the entire thickness of the adjacent first layer, thereby allowing the second element to diffuse throughout the entire film (the entire thickness of the film), thereby controlling the distribution of the composition ratio in the thickness direction of the film.

[0105] (k) By setting the first number (m times) and the second number (n times) to be 1 or more and 10 or less, the second element can be diffused throughout the thickness direction of the film, and the composition ratio of the second element can be made substantially uniform. If the first number and the second number exceed 10, the diffusion of the second element cannot reach the thickness direction of the film, and the composition ratio of the second element may become uneven.

[0106] (4) Modifications The substrate processing sequence in this embodiment can be modified as shown in the following modifications. These modifications can be combined as desired. Unless otherwise specified, the processing procedures and processing conditions in each step of each modification can be the same as the processing procedures and processing conditions in each step of the substrate processing sequence described above.

[0107] (Variation 1) As shown in FIG. 6( a), in addition to the step of performing a first cycle including the first and second steps, a step of performing a second cycle including the first and second steps may be further included. In this case, the ratio of the second number of times (n times) to the first number of times (m times) in the first cycle may be different from the ratio of the second number of times (n' times) to the first number of times (m' times) in the second cycle. That is, the ratio of the second number of times to the first number of times may be changed depending on the number of times the cycle including the first and second steps has been performed. In this case, the number of times the first cycle is performed (p times) and the number of times the second cycle is performed (p' times) may be the same or different. m, m', n, n', p, and p' are all integers of 1 or greater.

[0108] Specifically, for example, the step of performing the second cycle may be performed after the step of performing the first cycle, and the ratio (n / m) of the second number of times to the first number of times in the first cycle may be larger than the ratio (n' / m') of the second number of times to the first number of times in the second cycle. That is, the composition ratio of the second element in the film formed in the preceding cycle (first cycle) may be larger than the composition ratio of the second element in the film formed in the subsequent cycle (second cycle). Also, for example, the number of times the second cycle is performed (p' times) may be larger than the number of times the first cycle is performed (p times).

[0109] Furthermore, in addition to the first and second cycles, the method may further include a step of performing a third cycle including steps 1 and 2. In this case, the ratio of the second number of times to the first number of times in the first cycle, the second cycle, and the third cycle may be different from each other.

[0110] This modification provides the same effects as those obtained by the above-described embodiment. Furthermore, this modification allows for the formation of multiple layers each having a different composition ratio of the second element. This allows for the composition ratio of the second element to be varied in the thickness direction of the film, creating a gradient in the composition ratio.

[0111] Furthermore, in this modification, by making the ratio (n / m) of the second number of times to the first number of times in the first cycle larger than the ratio (n' / m') of the second number of times to the first number of times in the second cycle, for example, in a process for forming a charge trap film on a blocking film as one of the manufacturing processes for a nonvolatile memory cell such as a NAND flash memory, it is possible to form a layer with a high composition ratio of the second element and a high charge trap density on the side closer to the blocking film, and a layer with a low composition ratio of the second element and a low charge trap density on the side farther from the blocking film (see FIG. 9 ), thereby improving the electrical characteristics of the charge trap film.

[0112] Furthermore, in this modified example, by performing the second cycle a number of times (p' times) greater than the number of times (p times) the first cycle is performed, the thickness of the layer having a small composition ratio of the second element can be made greater than the thickness of the layer having a large composition ratio of the second element (see Figure 9).

[0113] Furthermore, in this modified example, by changing the ratio of the second number of times to the first number of times in the first cycle, the second cycle, and the third cycle, the composition ratio of the second element can be changed stepwise in the thickness direction of the film.

[0114] (Variation 2) As shown in FIG. 6(b), step B1 may further include a period after the first period in which the supply of the second source gas is continued while the supply of the third source gas is continued. That is, step B1 and step B2 may each include a period in which the second source gas and the third source gas are simultaneously supplied. Note that the notation 2+3 shown in FIG. 6(b) indicates an overlapping period between the supply period of the second source gas (the execution period of step B1) and the supply period of the third source gas (the execution period of step B2). This also applies to the notation 2+4 shown in FIG. 7(b).

[0115] In this modified example, the supply amount of the second source gas in the first period (specifically, at least one of the length of the first period in step B1 and the supply flow rate of the second source gas in the first period) may be set so that the composition ratio of the second element in the second layer becomes a predetermined ratio.

[0116] According to this modification, the same effects as those obtained by the above-described embodiment can be obtained.

[0117] (Variation 3) A non-H-containing gas may be used as the second source gas, and the cycle including the above-described steps B1, B2, and B3 may further include step B4 of supplying a fourth source gas containing the first element, the third halogen element, and H before supplying the third source gas (see FIG. 7(a)). Note that in FIG. 7(a), the fourth source gas is denoted as 4. This also applies to FIGS. 7(b) and 8(b) described below.

[0118] In this modification, the second source gas may be, for example, one or more of the non-H-containing halosilane gases listed in the above embodiment.

[0119] The fourth source gas may be, for example, an H-containing halosilane gas containing Si as the first element, a third halogen element, and H. The third halogen element includes Cl, F, Br, I, etc. The third halogen element may be the same element as the first halogen element and the second halogen element, or may be a different element. The fourth source gas may be, for example, one or more of the H-containing halosilane gases listed in the above embodiments.

[0120] In this modification, the composition ratio of the second element contained in the second layer may be adjusted by adjusting the ratio between the supply amount of the second source gas and the supply amount of the fourth source gas. Specifically, the composition ratio of the second element contained in the second layer may be adjusted by adjusting at least one of the supply flow rate and the supply time of either the second source gas or the fourth source gas.

[0121] In this modified example, the ratio of the supply amount of the second source gas to the supply amount of the fourth source gas may be changed depending on the number of times a cycle including the first step and the second step has been executed (i.e., depending on the number of times the cycle has been executed).

[0122] According to this modification, the same effect as that obtained by the above-described embodiment can be obtained. In this modification, a fourth source gas capable of forming H termination, which serves as an adsorption site for the third source gas (specifically, the second element), is further supplied to the surface of the wafer 200 before the supply of the third source gas, thereby increasing the composition ratio of the second element in the film.

[0123] Furthermore, in this modification, the ratio between the supply amounts of the second source gas and the fourth source gas can be adjusted to adjust the composition ratio of the second element contained in the second layer.

[0124] Furthermore, in this modified example, the composition ratio of the second element in the thickness direction of the film can be changed by changing the ratio between the supply amount of the second source gas and the supply amount of the fourth source gas depending on the number of times the cycle is performed.

[0125] In addition, in this modification, an example in which purging is performed between step B1 and step B4 has been described, but as shown in Fig. 7(b), the execution period of step B1 and the execution period of step B4 may be at least partially overlapped. In this modification, the same effects as those of the above modification can be obtained.

[0126] 8A , the method may further include a third step of forming a third layer containing the first element and the second element by performing a cycle including: step C1 of supplying a second source gas to the wafer 200; step C2 of supplying a second reactive gas after the supply of the second source gas has been performed for a third period in step C1; and step C3 of supplying a third source gas after the supply of the second reactive gas has been performed for a fourth period in step C2. The cycle including the first step, second step, and third step may be performed a predetermined number of times (p times) to form a film containing the first element and the second element, which is composed of the first layer, the second layer, and the third layer, on the wafer 200. r and p are integers of 1 or greater.

[0127] In this modification, the ratios of the first number (m times), the second number (n times), and the third number (r times) may be set so that the composition ratio of the second element in the film is a predetermined ratio. The first number (m times) may be set to zero depending on the desired composition ratio of the second element.

[0128] This modification provides the same effects as those provided by the above-described embodiment. Furthermore, in the third step, the halogen termination formed on the outermost surface of the wafer 200 by the supply of the second source gas is desorbed by the reactive gas, thereby increasing the number of adsorption sites (e.g., N—H terminations) on which the third source gas can be adsorbed. Therefore, in the third step, the adsorption probability of the third source gas is increased compared to the second step, and the composition ratio of the second element contained in the third layer can be increased compared to the second layer.

[0129] Furthermore, according to this modification, by adjusting the ratio of the number of stacked layers between the first layer not containing the second element and the second and third layers containing the second element at different composition ratios, the composition ratio of the second element in the film can be controlled to a desired value.

[0130] 8(b), the method may further include a third step of forming a third layer containing the first element and the second element by performing a cycle including: Step D1 of supplying a fourth source gas containing a first element, a third halogen element, and H; Step D2 of supplying a third source gas after the supply of the fourth source gas has been performed for a first period in Step D1; and Step D3 of supplying a second reactant gas after the supply of the third source gas has been performed for a second period in Step D2; and by performing a cycle including the first step, the second step, and the third step, a film containing the first element and the second element and composed of the first layer, the second layer, and the third layer may be formed on the wafer 200. As the fourth source gas, for example, one or more of the H-containing halosilane gases listed in the above embodiments may be used.

[0131] In this modification, the ratios of the first number (m times), the second number (n times), and the third number (r times) may be set so that the composition ratio of the second element in the film is a predetermined ratio. The first number (m times) may be set to zero depending on the desired composition ratio of the second element.

[0132] According to this modification, the same effects as those obtained by the above-described embodiment can be obtained. Furthermore, in this modification, in the third step, before the third source gas is supplied, an H termination capable of adsorbing the third source gas can be formed on the surface of the wafer 200, so that the adsorption rate of the third source gas can be increased compared to the second step, and the composition ratio of the second element contained in the third layer can be increased compared to the second layer.

[0133] Furthermore, according to this modification, by adjusting the ratio of the number of stacked layers between the first layer not containing the second element and the second and third layers containing the second element at different composition ratios, the composition ratio of the second element in the film can be controlled to a desired value.

[0134] 8( c), the method may include a third step of forming a third layer containing the first element by performing a cycle including Step A1 and Step A2 a third number (s times), and a fourth step of forming a fourth layer containing the first element and the second element by performing a fourth number (t times) of cycles including: Step C1 of supplying a second source gas; Step C2 of supplying a second reactive gas after the supply of the second source gas has been performed for a third period in Step C1; and Step C3 of supplying a third source gas after the supply of the second reactive gas has been performed for a fourth period in Step C2. A film containing the first element and the second element, consisting of a first layer, a second layer, a third layer, and a fourth layer, may be formed on the wafer 200 by performing a first cycle including the first and second steps and a second cycle including the third and fourth steps. s and t are integers of 1 or greater.

[0135] This modification provides the same effects as those obtained by the above-described embodiment. Furthermore, in this modification, in the fourth step, similar to the third step in the fourth modification, the adsorption probability of the third source gas is increased compared to the second step, and the composition ratio of the second element contained in the fourth layer can be increased compared to the second layer. Therefore, by further performing the second cycle in which the fourth step is performed, the composition ratio of the second element can be changed in the thickness direction of the film.

[0136] Other Aspects of the Present Disclosure The above describes specific aspects of the present disclosure. However, the present disclosure is not limited to the above aspects and can be modified in various ways without departing from the spirit and scope of the present disclosure.

[0137] In the present disclosure, for example, the first reactive gas and the second reactive gas may be oxygen (O ２ ) gas, ozone (O ３ ) gas, water vapor (H ２ O gas), nitric oxide (NO) gas, nitrous oxide (N ２ O) gas, hydrogen peroxide (H ２ O ２ ) gas, hydrogen (H ２ ) gas + oxygen (O ２ ) Gas, H ２ Gas + ozone (O３ ) gas (i.e., gas containing oxygen (O) as a third element), NH ３ Gas, hydrogen (H ２ ) Gas, H ２ Gas + O ２ The H-containing gas may partially overlap with the oxidizing gas or the hydrogen nitride gas. ２ Gas + O ２ In the case of a combination of two gases, such as "gas," ２ Gas and O ２ In this embodiment, the same effects as those in the above embodiment can be obtained.

[0138] In the present disclosure, for example, at least one of the first element and the second element is preferably a metal element or a metalloid element. In this specification, the term "metalloid element" refers to boron (B), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te), in addition to Si. Examples of metal elements that can be used include zirconium (Zr), hafnium (Hf), tantalum (Ta), niobium (Nb), aluminum (Al), molybdenum (Mo), and tungsten (W), in addition to Ti. Gases containing halides of the above-mentioned metal elements or metalloid elements can be used as the first source gas, the second source gas, and the third source gas. One or more of these can be used as the first source gas, the second source gas, and the third source gas. However, the first element and the second element are different metal elements or metalloid elements. This embodiment also achieves the same effects as the above-described embodiment.

[0139] In the present disclosure, the film to be formed can be, for example, a metalloid nitride film doped with the above-mentioned metal element (e.g., a SiN film doped with the above-mentioned metal element). The film to be formed may be a metal nitride film doped with the above-mentioned metalloid element (e.g., a titanium nitride film (TiN film) doped with the above-mentioned metalloid element). The film to be formed may be a metal nitride film doped with the metal element (e.g., a TiN film doped with the above-mentioned metal element). The film to be formed may be a metalloid nitride film doped with the above-mentioned metalloid element (e.g., a SiN film doped with the above-mentioned metalloid element). Furthermore, an oxide film may be formed instead of a nitride film. In this embodiment, the same effects as those in the above-mentioned embodiment can be obtained.

[0140] In the present disclosure, for example, the first number (m times) and the second number (n times) may be equal to or greater than 11. By setting the first number and the second number to be equal to or greater than 11, a bias may be generated in the composition ratio of the second element in the thickness direction of the film, and layers with different composition ratios of the second element may be formed.

[0141] The present disclosure can be suitably applied, for example, to a case where a film is formed using a single-wafer substrate processing apparatus that processes one or several substrates at a time. The present disclosure can also be suitably applied to a case where a film is formed using a substrate processing apparatus having a cold-wall processing furnace. The present disclosure can also be suitably applied, for example, to a case where a gas is activated by plasma generated inside or outside the processing chamber 201, or a case where a gas is activated by irradiating the gas with electromagnetic waves using a lamp or the like.

[0142] When using these substrate processing apparatuses, each process can be performed using the same processing procedures and conditions as in the above-described embodiments and modifications, and the same effects as in the above-described embodiments and modifications can be obtained.

[0143] The above-described embodiments and modifications may be used in combination as appropriate. The processing procedures and processing conditions in such a case may be the same as those of the above-described embodiments and modifications, for example.

[0144] 200 wafers (substrates)

Claims

1. A substrate processing method comprising: a first step of forming a first layer containing a first element by performing a first cycle a first number of times, the first step including: (a-1) supplying a first source gas containing a first element to a substrate; and (a-2) supplying a first reactive gas to the substrate; and a second step of forming a second layer containing the first element and the second element by performing a second cycle a second number of times, the second step including: (b-1) supplying a second source gas containing the first element and a first halogen element to the substrate; (b-2) after the supply of the second source gas has been carried out for a first period in (b-1), supplying a third source gas containing a second halogen element and a second element not contained in the first layer to the substrate; and (b-3) supplying a second reactive gas to the substrate after the supply of the third source gas has been carried out for a second period in (b-2).

2. The substrate processing method according to claim 1, wherein the third source gas does not contain hydrogen.

3. The substrate processing method according to claim 1, wherein the second source gas does not contain hydrogen.

4. The substrate processing method according to claim 1, wherein the first source gas and the second source gas are the same gas.

5. The substrate processing method according to claim 1, wherein the first reactive gas and the second reactive gas are the same gas.

6. The substrate processing method according to claim 1, wherein the first reactive gas and the second reactive gas are gases containing a third element, and the film is a film containing the third element.

7. The substrate processing method according to claim 1, wherein the ratio of the second number of times to the first number of times is set so that the composition ratio of the second element in the film becomes a predetermined ratio.

8. The substrate processing method according to claim 1, wherein at least one of the supply flow rate and supply time of the second source gas in (b-1) is set so that the composition ratio of the second element in the second layer becomes a predetermined ratio.

9. The substrate processing method according to claim 1, wherein the film is formed by repeating a cycle including the first step and the second step a third number of times, the third number being two or more.

10. The substrate processing method according to claim 1, wherein the film is a charge trap film of a nonvolatile memory cell.

11. The substrate processing method according to claim 1, wherein the thickness of the first layer is such that the second element contained in the second layer can diffuse throughout the entire thickness direction of the adjacent first layer.

12. The substrate processing method of claim 1, comprising: a step of performing a first cycle including the first step and the second step; and a step of performing a second cycle including the first step and the second step, wherein a ratio of the second number of times to the first number of times in the first cycle is different from a ratio of the second number of times to the first number of times in the second cycle.

13. The substrate processing method according to claim 1, wherein (b-1) further includes a period after the first period in which the supply of the second source gas is continued while the supply of the third source gas is continued.

14. The substrate processing method of claim 1, wherein the second source gas is a gas that does not contain hydrogen, and the cycle including (b-1), (b-2), and (b-3) further includes: (b-4) a step of supplying a fourth source gas containing the first element, a third halogen element, and hydrogen to the substrate before supplying the third source gas to the substrate.

15. The substrate processing method of claim 1, further comprising a third step of forming a third layer containing the first element and the second element by performing a cycle including: (c-1) a step of supplying the second source gas to the substrate; (c-2) a step of supplying the second reactive gas to the substrate after the supply of the second source gas has been carried out for a third period in (c-1); and (c-3) a step of supplying the third source gas to the substrate after the supply of the second reactive gas has been carried out for a fourth period in (c-2), wherein a film containing the first element and the second element is formed on the substrate by performing a cycle including the first step, the second step, and the third step.

16. The substrate processing method of claim 1, further comprising a third step of forming a third layer containing the first element and the second element by performing a cycle including: (d-1) a step of supplying a fourth source gas containing the first element, a third halogen element, and hydrogen to the substrate; (d-2) a step of supplying the third source gas to the substrate after the supply of the fourth source gas has been completed for a first period in (d-1); and (d-3) a step of supplying the second reactive gas to the substrate after the supply of the third source gas has been completed for a second period in (d-2); wherein a film containing the first element and the second element is formed on the substrate by performing a cycle including the first step, the second step, and the third step.

17. The substrate processing method of claim 1, comprising: a third step of forming a third layer containing the first element by performing a cycle including (a-1) and (a-2) a third time; and a fourth step of forming a fourth layer containing the first element and the second element by performing a fourth number of cycles including: (c-1) a step of supplying the second source gas to the substrate; (c-2) a step of supplying the second reactive gas to the substrate after the supply of the second source gas has been performed for a third period in (c-1); and (c-3) a step of supplying the third source gas to the substrate after the supply of the second reactive gas has been performed for a fourth period in (c-2), wherein a film containing the first element and the second element is formed on the substrate by performing a first cycle including the first step and the second step; and a second cycle including the third step and the fourth step.

18. A method for manufacturing a semiconductor device, comprising: a first step of forming a first layer containing the first element by performing a first number of cycles including: (a-1) a step of supplying a first source gas containing a first element to a substrate; and (a-2) a step of supplying a first reactive gas to the substrate; and a second step of forming a second layer containing the first element and the second element by performing a second number of cycles including: (b-1) a step of supplying a second source gas containing the first element and a first halogen element to the substrate; (b-2) a step of supplying a third source gas containing a second halogen element and a second element not contained in the first layer to the substrate after the supply of the second source gas has been carried out for a first period in (b-1); and (b-3) a step of supplying a second reactive gas to the substrate after the supply of the third source gas has been carried out for a second period in (b-2).

19. A program for causing a substrate processing apparatus to execute, by a computer, a procedure for forming a film containing the first element and the second element on the substrate by performing the following: a first procedure for forming a first layer containing the first element by performing a first cycle a first time, the cycle including: (a-1) a procedure for supplying a first source gas containing a first element to a substrate; and (a-2) a procedure for supplying a first reactive gas to the substrate; and a second procedure for forming a second layer containing the first element and the second element by performing a second cycle a second time, the cycle including: (b-1) a procedure for supplying a second source gas containing the first element and a first halogen element to the substrate; (b-2) a procedure for supplying a third source gas containing a second halogen element and a second element not contained in the first layer to the substrate after the supply of the second source gas has been completed for a first period in (b-1); and (b-3) a procedure for supplying a second reactive gas to the substrate after the supply of the third source gas has been completed for a second period in (b-2).

20. A gas supply system that supplies a first source gas containing a first element, a second source gas containing the first element and a first halogen element, a third source gas containing a second halogen element and a second element, a first reactive gas, and a second reactive gas to a substrate; a first process that forms a first layer containing the first element by performing a first cycle including: (a-1) a process of supplying the first source gas to the substrate; and (a-2) a process of supplying the first reactive gas to the substrate; and a second process that forms a second layer containing the first element and the second element by performing a second cycle including: (b-1) a process of supplying the second source gas to the substrate; (b-2) a process of supplying the third source gas containing the second element not contained in the first layer to the substrate after the supply of the second source gas has been performed for a first period in (b-1); and (b-3) a process of supplying the second reactive gas to the substrate after the supply of the third source gas has been performed for a second period in (b-2). a control unit configured to be able to control the gas supply system so as to perform a process of forming a film containing the first element and the second element on the substrate by performing the process above.

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