Substrate processing methods, semiconductor device manufacturing methods, processes, and substrate processing apparatus

Abstract

The objective of this invention is to provide a substrate processing method that can precisely form films on a substrate. The substrate processing method comprises: (a) in a substrate having surfaces of a first material, a second material, and a third material sequentially adjacent to each other, selectively forming a first sacrificial film on the surface of the first material and a second sacrificial film on the surface of the third material, respectively, with respect to the surface of the second material; (b) forming a separation film within a recess with the first and second sacrificial films as sidewalls; and (c) selectively removing the first and second sacrificial films with respect to the separation film, the first material, and the third material, thereby forming a first recess with one sidewall of the separation film as a sidewall and the surface of the first material as a bottom surface, and a second recess with the other sidewall of the separation film as a sidewall and the surface of the second material as a bottom surface.

Description

Substrate processing methods, semiconductor device manufacturing methods, processes, and substrate processing apparatus This invention relates to a substrate processing method, a method for manufacturing a semiconductor device, a process, and a substrate processing apparatus. As a step in the manufacturing of semiconductor devices, a process is sometimes performed to form a film on the surface of a substrate (see, for example, Patent Document 1). [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Publication No. 2021-136349 (Problem to be solved by the invention) This invention provides a technique for precisely forming films on a substrate. (Technical means to solve the problem) According to one aspect of the present invention, a technique is provided comprising the following steps (a), (b), and (c): (a) in a substrate having a structure in which the surfaces of a first material, a second material, and a third material are sequentially adjacent, a first sacrificial film is selectively formed on the surface of the first material and a second sacrificial film is formed on the surface of the third material, respectively, with respect to the surface of the second material; (b) a separation film is formed in a recess with the first and second sacrificial films as sidewalls; (c) the first and second sacrificial films are selectively removed with respect to the separation film, the first material, and the third material, thereby forming a first recess with one side of the separation film as a sidewall and the surface of the first material as a bottom surface, and a second recess with the other side of the separation film as a sidewall and the surface of the second material as a bottom surface. (Effects compared to prior art) According to the present invention, a film can be precisely formed on a substrate. <One Embodiment of the Invention> One embodiment of the invention will be described below with reference to Figures 1 to 3, 4(a) to 4(e), and 5(a) to 5(d). Furthermore, the figures used in the following description are illustrative, and the dimensional relationships and ratios of the components shown in the figures may not necessarily correspond to actual dimensions. Also, the dimensional relationships and ratios of the components in the multiple figures may not necessarily be consistent with each other. (1) The structure of the substrate processing apparatus is shown in Figure 1. The processing furnace 202 of the substrate processing apparatus has a reaction tube 203. A manifold 209 is provided below the reaction tube 203. The processing container is mainly composed of the reaction tube 203 and the manifold 209. A processing chamber 201 is formed inside the processing container. The processing chamber 201 is configured to accommodate a wafer 200, which serves as a substrate. A heater 207 is provided outside the reaction tube 203 to heat the wafer 200 inside the processing chamber 201. The heater 207 also functions as an activation mechanism that uses heat to activate the gas inside the processing chamber 201. A temperature sensor 263 is provided inside the reaction tube 203. Nozzles 249a-249c are installed inside the processing chamber 201. As shown in Figure 2, the nozzles 249a-249c are arranged vertically along the inner wall of the reaction tube 203 and upwards towards the arrangement direction of the wafers 200. Multiple gas supply holes 250a-250c are provided on the sides of the nozzles 249a-249c from the bottom to the top of the reaction tube 203. Gas supply pipes 232a-232c are connected to nozzles 249a-249c. Mass flow controllers (MFCs) 241a-241c and valves 243a-243c are installed in gas supply pipes 232a-232c. Gas supply pipes 232d, 232e, and 232g are connected downstream of valve 243a from gas supply pipe 232a. Gas supply pipes 232f and 232h are connected downstream of valve 243b from gas supply pipe 232b. Gas supply pipe 232i is connected downstream of valve 243c from gas supply pipe 232c. MFCs 241d-241i and valves 241d-241i are installed in gas supply pipes 232d-232i. The first raw material is supplied to the processing chamber 201 via gas supply pipe 232a through MFC 241a, valve 243a, and nozzle 249a. The gas supply pipe 232b supplies the reactants (oxidant and nitriding agent) to the processing chamber 201 via MFC 241b, valve 243b, and nozzle 249b. The modifier is supplied to the processing chamber 201 via gas supply pipe 232c, MFC 241c, valve 243c, and nozzle 249c. The second raw material is supplied to the processing chamber 201 via gas supply pipe 232d, MFC 241d, valve 243d, gas supply pipe 232a, and nozzle 249a. The third raw material is supplied to the processing chamber 201 via gas supply pipe 232e, MFC 241e, valve 243e, gas supply pipe 232a, and nozzle 249a. The catalyst is supplied to the processing chamber 201 via gas supply pipe 232f, MFC 241f, valve 243f, gas supply pipe 232b, and nozzle 249b. Inert gas is supplied to the treatment chamber 201 via gas supply pipes 232g~232i, MFC 241g~241i, valves 243g~243i, gas supply pipes 232a~232c, and nozzles 249a~249c. The inert gas serves as a flushing gas, carrier gas, and dilution gas. The system comprises: a first raw material supply system consisting of gas supply pipe 232a, MFC 241a, and valve 243a; a reactant (oxidizing agent and nitriding agent) supply system consisting of gas supply pipe 232b, MFC 241b, and valve 243b; a modifier supply system consisting of gas supply pipe 232c, MFC 241c, and valve 243c; a second raw material supply system consisting of gas supply pipe 232d, MFC 241d, and valve 243d; a third raw material supply system consisting of gas supply pipe 232e, MFC 241e, and valve 243e; a catalyst supply system consisting of gas supply pipes 232g-232i, MFC 241g-241i, and valves 243g-243i; and an inert gas supply system consisting of gas supply pipes 232g-232i, MFC 241g-241i, and valves 243g-243i. Any or all of the aforementioned supply systems can also be configured as an aggregated supply system 248 composed of valves 243a~243i, MFCs 241a~241i, etc. Furthermore, when different reactants are used in the subsequent processing steps (steps A, B, D, E), a separate reactant supply system is provided for each different reactant to supply the reactant to nozzle 249c. An exhaust port 231a is provided below the reaction tube 203. The exhaust pipe 231 is connected to the vacuum pump 246 via a pressure sensor 245 and an APC (Auto Pressure Controller) valve 244. The exhaust system mainly consists of the exhaust pipe 231, the APC valve 244, and the pressure sensor 245. Alternatively, the vacuum pump 246 can be included in the exhaust system. A sealing cover 219 is provided below the manifold 209. A rotation mechanism 267 is provided on the sealing cover 219 to rotate the wafer boat 217 (described later). The sealing cover 219 is raised and lowered by a wafer boat lift 115. The wafer boat lift 115 functions as a transport mechanism to move the wafer 200 inside and outside the processing chamber 201. A baffle 219s is provided below the manifold 209 to airtightly seal the lower opening of the manifold 209. The opening and closing action of the baffle 219s is controlled by the baffle opening and closing mechanism 115s. The crystal boat 217, which serves as a substrate support, is configured to support multiple wafers 200, for example, 25 to 200 wafers 200, arranged horizontally and aligned with their centers in a vertical direction. The lower part of the crystal boat 217 is supported by multiple sections of heat insulation plates 218. Furthermore, the substrate processing apparatus may also include a first etching unit (first etching apparatus) that performs at least one of the following steps: B2 (separation film formation) and D2 (formation of the first dielectric film and the second dielectric film). This unit may include, for example, an etching gas supply system for supplying etching gas into a processing container housing the wafer 200, a plasma generation unit for plasma-excited etching gas within the processing container by means of electrodes (antennas) supplied with high-frequency power, and a bias adjustment unit for adjusting the potential (bias) of the wafer 200. In at least one of steps B2 and D2, this unit can be used to perform anisotropic plasma etching on the wafer 200. Furthermore, the substrate processing apparatus may also include a second etching unit (second etching apparatus) for performing step C (formation of the first and second recesses) described later. This unit may, for example, include an etchant supply system that supplies etchant (etching solution or etching gas) to the wafer 200 contained in a processing container, or an immersion container configured to immerse the wafer 200 in an etching solution. In step C, this unit can be used to perform wet etching or dry etching on the wafer 200. Moreover, the substrate processing apparatus including at least one of the first and second etching units may also be configured as a processing system interconnected via a communication network. As shown in Figure 3, the control unit, i.e., the controller 121, is configured to include a CPU 121a, RAM (Random Access Memory) 121b, a memory device 121c, and an I / O port 121d. The RAM 121b, memory device 121c, and 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. The controller 121 can be connected to an external memory device 123. The memory device 121c is composed of, for example, flash memory, HDD (Hard Disk Drive), SSD, etc. The memory device 121c contains readable and stored control programs that control the operation of the processing device, or process recipes that record the procedures or conditions for the substrate processing described later. The process recipe functions as a program, and it is a combination of various programs in the substrate processing described later, executed by the controller 121, to obtain a predetermined result. Hereinafter, the process recipe and control program are collectively referred to as a program. Furthermore, the process recipe is also simply referred to as a recipe. In this specification, when the term "program" is used, it refers to the case containing only the recipe unit, the case containing only the control program unit, or the case containing both. I / O port 121d is connected to the aforementioned MFCs 241a-241i, valves 243a-243i, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotating mechanism 267, crystal boat lift 115, baffle opening and closing mechanism 115s, etc. I / O port 121d can also be connected to the first etching unit and the second etching unit. CPU 121a is configured to read and execute the control program from memory device 121c, and to read the recipe from memory device 121c in conjunction with the input of operation instructions from input / output device 122. CPU 121a is configured to control, according to the read recipe, the flow rate adjustment of various substances using MFC 241a~241i, the opening and closing of valves 243a~243i, the opening and closing of APC valve 244 and the pressure adjustment using APC valve 244 based on pressure sensor 245, the start and stop of vacuum pump 246, the temperature adjustment of heater 207 based on temperature sensor 263, the rotation and speed adjustment of crystal boat 217 by rotating mechanism 267, the lifting and lowering of crystal boat 217 by crystal boat elevator 115, and the opening and closing of baffle 219s by baffle opening and closing mechanism 115s. CPU 121a can also be configured to control the first etching unit and the second etching unit. The controller 121 is configured to install the aforementioned program, recorded and stored in the external memory device 123, into a computer. The external storage device 123 includes magnetic disks such as HDDs, optical disks such as CDs, magneto-optical disks such as MO drives, USB memory, semiconductor memory such as SSDs, etc. The memory device 121c and the external memory device 123 constitute a recording medium that can be read by a computer. Hereinafter, these are collectively referred to as recording media. In this specification, the term "recording media" refers to the case containing only the memory device 121c, the case containing only the external memory device 123, or the case containing both. Furthermore, the program can also be provided to the computer using communication means such as a network. (2) The substrate processing step is one of the manufacturing steps (manufacturing method) of the semiconductor device using the above-described substrate processing apparatus. Specifically, it is an example of the processing sequence for forming a film on the surface of the wafer 200, which serves as the substrate. It will be mainly described using Figures 4(a) to 4(e) and Figures 5(a) to 5(d). Some steps (steps A1, A2, B1, D1, E) in the series of processing sequences shown below are performed by the above-described substrate processing apparatus. At this time, the operation of each part constituting the substrate processing apparatus is controlled by the controller 121. In the processing sequence of this sample, the following steps are performed: (a) In a wafer 200 having a structure in which the surfaces of a first material, a second material, and a third material are sequentially adjacent, step A is performed to selectively form a first sacrificial film on the surface of the first material and a second sacrificial film on the surface of the third material, respectively, relative to the surface of the second material; (b) Step B is performed to form a separation film in a recess with the first and second sacrificial films as sidewalls; (c) Step C is performed to selectively remove the first and second sacrificial films relative to the separation film, the first material, and the third material, thereby forming a first recess with one side of the separation film as a sidewall and the surface of the first material as the bottom surface, and a second recess with the other side of the separation film as a sidewall and the surface of the second material as the bottom surface. Furthermore, in the following examples, the following situations will be explained. As shown in Figures 4(a) and 4(b), in step A: (a-1) step A1, which selectively forms a first adsorption barrier layer on the surface of the second material to prevent the adsorption of the first raw material relative to the respective surfaces of the first and third materials; and (a-2) step A2, which forms a first sacrificial film on the surface of the first material and a second sacrificial film on the surface of the third material by supplying the first raw material to the wafer 200. Furthermore, in the following examples, the following situation will be explained. As shown in Figures 4(c) and 4(d), in step B, the following steps are performed: (b-1) forming an embedded membrane that is embedded in the recess and covers at least a portion of the upper surface of the first sacrificial membrane and the second sacrificial membrane respectively, step B1; and (b-2) retaining the portion of the embedded membrane formed in the recess as a separation membrane and removing the other portion, step B2. Furthermore, in the following example, the following situation will be explained. After performing step C above and forming the first recess and the second recess on the surface of wafer 200 as shown in FIG4(e), the following step D is further performed: (d) forming the first dielectric film in the first recess and forming the second dielectric film in the second recess respectively. Specifically, the following situation will be described. In step D, as shown in Figures 5(a) and 5(b), the following steps are performed: (d-1) forming a dielectric film embedded in the first recess and the second recess and covering at least a portion of the upper surface of the separation membrane; and (d-2) retaining the portions of the dielectric film embedded in the first recess and the second recess as the first dielectric film and the second dielectric film, respectively, and removing the other portions, in step D2. Furthermore, in the following example, the following situation will be explained. After step D is performed, step E is further performed, as shown in FIG5(c): By supplying an oxidant to wafer 200, a portion of the first material in contact with the interface of the first material and the first dielectric film is modified to the first replacement oxide film through the first dielectric film, and a portion of the third material in contact with the interface of the third material and the second dielectric film is modified to the second replacement oxide film through the second dielectric film. Furthermore, in the following example, the following situation will be explained. After step E is performed, step F is further performed, as shown in Figure 5(d): On the surface of wafer 200, that is, on the respective surfaces of the separation film, the first dielectric film and the second dielectric film formed on wafer 200, a tunnel oxide film and a channel film are sequentially deposited. In this specification, the term "wafer" is used to refer to the wafer itself, as well as to a laminate of a wafer and a predetermined layer or film formed on its surface. The term "wafer surface" is used to refer to the surface of the wafer itself, as well as the surface of a predetermined layer formed on the wafer. The phrase "forming a predetermined layer on the wafer surface" is used to refer to forming the predetermined layer directly on the surface of the wafer itself, as well as forming the predetermined layer on top of layers formed on the wafer. The term "substrate" has the same meaning as "wafer." In this specification, the terms "agent" and "substance" are used to include at least one of gaseous and liquid substances. Liquid substances include atomized substances. That is, the modifier, the first to third raw materials, and the reactants (oxidizing agent and nitriding agent) described later may each include gaseous substances, atomized substances or other liquid substances, or both. The following is a detailed explanation of the processing timing in this sample. After multiple wafers 200 are loaded (wafer filling) into the crystal boat 217, the baffle 219s is moved, and the lower opening of the manifold 209 is opened (baffle opening). Then, the crystal boat 217 supporting the multiple wafers 200 is lifted and moved into the processing chamber 201 by the crystal boat elevator 115 (crystal boat loading). As shown in Figure 4(a), the wafer 200 of the processed object has a structure on its surface in which the surfaces of a first material, a second material, and a third material are sequentially adjacent (hereinafter also referred to as an adjacent structure). On the surface of the wafer 200, three-dimensional structures such as trenches and holes are sometimes provided, and the aforementioned adjacent structure is sometimes provided on the three-dimensional portions such as the sidewalls of the trenches and holes. Furthermore, the aforementioned adjacent structure is sometimes also provided on the flat portions of the surface of the wafer 200. The second material can be an oxide, and the first and third materials can each be at least one of oxides or non-oxides in which the oxygen content ratio (i.e., the oxygen ratio or oxygen concentration in the material composition) is smaller than that of the second material. For example, the first and third materials can each be nitrides such as silicon nitride (SiN), and the second material can be an oxide such as silicon oxide (SiO). Furthermore, the first and third materials can each be materials in which at least a portion of the surface of a nitride such as SiN is naturally oxidized. Even under these conditions, the oxygen content of the naturally oxidized surface is lower than that of the second material. After the wafer boat is loaded, vacuum pump 246 is used to exhaust the vacuum (pressure reduction exhaust) to bring the processing chamber 201 to the desired pressure (vacuum level). Then, heater 207 is used to heat the wafer 200 within the processing chamber 201 to the desired processing temperature. Finally, rotation mechanism 267 begins rotating the wafer 200. The exhaust from the processing chamber 201, the heating of the wafer 200, and the rotation all continue at least until the processing of the wafer 200 is completed. (Step A) Next, the wafer 200 prepared in the processing chamber 201 is subjected to the following steps A1 and A2. [Step A1: Formation of the first adsorption barrier layer] In this step, valve 243c is opened to supply a modifier (inhibitor) to wafer 200. At this time, valves 243g to 243i can also be opened to supply inert gas into processing chamber 201. By performing step A1 under the conditions described later, as shown in FIG4(a), a first adsorption barrier layer (first inhibitor layer) that hinders the adsorption of the first raw material can be selectively formed on the surface of the second material relative to the surfaces of the first and third materials, respectively. The first adsorption barrier layer contains at least a portion of the molecular structure constituting the molecules of the modifier. In this invention, "selectively forming the first adsorption barrier layer on the surface of the second material" does not mean "forming the first adsorption barrier layer only on the surface of the second material," but rather means "the first adsorption barrier layer is preferentially formed on the surface of the second material, which is on the surfaces of the first, second, and third materials, respectively." That is, the above description does not completely exclude the formation of the first adsorption barrier layer on the surface of the first material or on the surface of the third material. The term "selectively" is used in substantially the same sense in the following steps. After selectively forming a first adsorption barrier layer on the surface of the second material, valve 243c is closed to stop supplying the modifier to the wafer 200. Then, a vacuum is vented from the processing chamber 201 to remove any gaseous substances remaining there. Next, valves 243g to 243i are opened to supply inert gas into the processing chamber 201 for cleaning. As a modifier, for example, (dimethylamino)trimethylsilane ((CH) can be used. 3) 2NSi(CH 3) 3) (Diethylamino)triethylsilane ((C 2H 5) 2NSi(C 2H 5) 3) (Dimethylamino)triethylsilane ((CH 3) 2NSi(C 2H 5) 3) (Diethylamino)trimethylsilane ((C 2H 5) 2NSi(CH 3) 3) (Dipropylamino)trimethylsilane ((C 3H 7) 2NSi(CH 3) 3) Alkylaminosilanes, etc. Furthermore, as a modifier, tetrakis(dimethylamino)silane (Si[N(CH)) can be used, for example. 3) 2] 4) Tris(dimethylamino)silane (Si[N(CH)) 3) 2] 3H), bis(diethylamino)silane (Si[N(C)) 2H 5) 2] 2H 2) Bis(tert-butylamino)silane (SiH) 2[NH(C 4H 9)] 2) (Diisopropylamino)silane (SiH) 3[N(C 3H 7) 2) etc. aminosilanes. As a modifier, one or more of these silicon (Si)-containing substances can be used. Examples of processing conditions for supplying Si-containing substances as modifiers in step A1 include: Processing temperature: room temperature (25°C) to 500°C, preferably room temperature to 250°C; Processing pressure: 5 to 1000 Pa; Processing time: 1 second to 120 minutes, preferably 30 seconds to 60 minutes; Modifier supply flow rate: 0.001 to 3 slm, preferably 0.001 to 0.5 slm; Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm. Furthermore, when numerical ranges are expressed as "25 to 500°C" in this specification, both the lower and upper limits are included within that range. Therefore, for example, "0 to 500°C" means "above 0°C and below 500°C". The same applies to other numerical ranges. Also, the processing temperature in this specification refers to the temperature of the wafer 200 or the temperature inside the processing chamber 201, and the processing pressure refers to the pressure inside the processing chamber 201. Furthermore, the processing time refers to the duration of the processing. Also, when the supply flow rate includes 0 slm, 0 slm means that the substance is not supplied. The same applies in the following description. Furthermore, fluorine (F) can be used as a modifier. 2) Nitrogen fluoride (NF) 3) Chlorine fluoride (ClF) 3) Hydrogen fluoride (HF), etc. One or more of these fluorine-containing (F) substances can be used as a modifier. Examples of processing conditions for supplying substance F as a modifier in step A1 include: Processing temperature: room temperature (25°C) to 300°C, preferably room temperature to 200°C; Processing pressure: 1 to 2000 Pa, preferably 1 to 1000 Pa; Processing time: 1 second to 60 minutes; Modifier supply flow rate: 0.001 to 2 slm, preferably 0.001 to 0.5 slm; Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm. Furthermore, in step A1, step A1(Si) of supplying Si-containing material as a modifier to wafer 200 and step A1(F) of supplying F-containing material as a modifier can be performed sequentially. [Step A2: Formation of the first sacrificial film and the second sacrificial film] In this step, the wafer 200 after the formation of the first adsorption barrier layer on the surface of the second material is subjected to the following steps (first raw material supply, reactant supply). As the reactant, for example, a nitriding agent can be used. [First Raw Material Supply] In this step, valve 243a is opened to supply the first raw material to wafer 200. At this time, valves 243g to 243i can also be opened to supply inert gas into processing chamber 201. By performing this step (first raw material supply) under the processing conditions described later, an adsorption layer of the first raw material can be selectively formed on the respective surfaces of the first material and the third material relative to the surface of the second material. The adsorption layer of the first raw material contains at least a portion of the molecular structure constituting the molecules of the first raw material. After the adsorption layer of the first raw material is formed, valve 243a is closed to stop the supply of the first raw material to wafer 200. Then, through the above procedure, gaseous substances and the like remaining in the processing chamber 201 are removed from the processing chamber 201, and the processing chamber 201 is cleaned using inert gas. [Reactant Supply] In this step, valve 243b is opened to supply reactant to wafer 200. At this time, valves 243g to 243i can also be opened to supply inert gas into processing chamber 201. By performing this step (reactant supply) under the processing conditions described later, the adsorption layer of the first raw material selectively formed on the respective surfaces of the first and third materials can be modified. When a nitriding agent is used as the reactant, the adsorption layer of the first raw material can be nitrided, forming a nitride layer containing the constituent elements of the first raw material on the respective surfaces of the first and third materials. After modifying the adsorption layer of the first raw material, valve 243b is closed to stop supplying the reactant to the wafer 200. Then, through the above procedure, gaseous substances remaining in the processing chamber 201 are removed from the processing chamber 201, and the processing chamber 201 is cleaned with inert gas. [Perform a predetermined number of times] Then, the cycle including the supply of the first raw material and the supply of the reactant will be performed a predetermined number of times (n). A Next, n A(Integers of 1 or 2 or higher). Therefore, as shown in FIG4(b), a first sacrificial film can be selectively formed on the surface of the first material and a second sacrificial film can be formed on the surface of the third material, respectively, relative to the surface of the second material. When using a Si-containing material as the first raw material and a nitriding agent as the reactant, nitriding films, such as silicon nitride films (SiN films), can be formed as the first and second sacrificial films. Furthermore, by forming the first and second sacrificial films, a recess is formed on the surface of the wafer 200, with the first and second sacrificial films as sidewalls and the surface of the second material as the bottom. Furthermore, the statement "selectively forming a first sacrificial film on the surface of the first material and a second sacrificial film on the surface of the third material, respectively, relative to the surface of the second material" does not completely exclude the formation of the first and second sacrificial films on the surface of the second material. Therefore, for example, by the partial detachment of the adsorption barrier layer in step A2, a discontinuous nitride layer may sometimes form on a portion of the surface of the second material. Also, for example, as shown in FIG4(b), in step A2, the first sacrificial film may be formed to protrude (exceed, cover, cross the boundary) towards one side of the surface of the second material relative to the boundary between the surfaces of the second and first materials. This is because, in the process of repeatedly forming the first sacrificial film, the first sacrificial film itself can be used as a substrate, growing in a manner where the first sacrificial film protrudes above the second material. Also, for example, in step A2, similarly to the first sacrificial film, the second sacrificial film may be formed to protrude (exceed, cover, cross the boundary) towards one side of the surface of the second material relative to the boundary between the surfaces of the second and third materials. Furthermore, if the aforementioned discontinuous nitride layer is formed on the surface of the second material, it is preferable to modify (oxidize) it into an oxide equivalent to the second material in step B1 described later. Furthermore, the thickness of the separation membrane described later is determined by the thicknesses of the first sacrificial membrane and the second sacrificial membrane. Therefore, in step A2, the first sacrificial membrane and the second sacrificial membrane are formed until they reach a predetermined thickness corresponding to the desired thickness of the separation membrane. Specifically, for example, in step A2, the first sacrificial membrane and the second sacrificial membrane are formed until they reach a thickness equal to the desired thickness of the separation membrane. Moreover, the thickness of the first sacrificial membrane and the second sacrificial membrane is greater than the thickness of the first adsorption barrier layer. As a first raw material, for example, the aforementioned alkylaminosilanes and aminosilanes can be used. Also, as a first raw material, dichlorosilane (SiH) can be used. 2Cl 2) Tetrachlorosilane (SiCl) 4) Hexachlorosilane (Si) 2Cl 6) Octachloropropane (Si) 3Cl 8) Isochlorosilanes. One or more of these Si-containing substances may be used as the first raw material. As a reactant (nitriding agent), ammonia (NH4+) can be used, for example. 3) Diazide (N 2H 2) Hydrazine (N 2H 4) N 3H 8. Hydrogen nitride. One or more of these nitrogen-containing (N) substances may be used as reactants. Examples of processing conditions for supplying the first raw material in step A2 include: Processing temperature: room temperature (25°C) to 500°C, preferably room temperature to 400°C; Processing pressure: 1 to 2000 Pa, preferably 1 to 1333 Pa; Processing time: 1 to 180 seconds, preferably 10 to 120 seconds; First raw material supply flow rate: 0.001 to 2 slm, preferably 0.01 to 1 slm; Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm. Examples of processing conditions for supplying the reactant in step A2 include: processing pressure: 1~4000 Pa, preferably 1~1333 Pa; reactant supply flow rate: 0.01~20 slm, preferably 0.01~10 slm; other processing conditions may be the same as those for supplying the first raw material. As shown, the first sacrificial film and the second sacrificial film are formed under relatively low temperature processing conditions. Therefore, the first and second sacrificial films are composed of nitrides with lower density compared to the first and third materials serving as substrates. More specifically, it is preferable that the processing temperature of the first and second sacrificial films is lower than the processing temperature at which the first and third materials serving as substrates are formed. Furthermore, by appropriately selecting the first raw material and reactant as the first and second sacrificial films, silicon carbonitride films (SiCN films), silicon carbide films (SiC films), silicon oxycarbonitrile films (SiOCN films), silicon oxycarbonitrile films (SiOC films), and silicon oxynitride films (SiON films) can also be formed. That is, the first and second sacrificial films can each contain at least one of predetermined elements such as Si and nitrogen and carbon, and can also be films composed of different compositions from the first and third materials used as substrates. (Step B) Next, the wafer 200 after the first sacrificial film and the second sacrificial film are formed on the surface is subjected to the following steps B1 and B2. [Step B1: Formation of Embedded Film] In this step, the wafer 200 undergoes the following steps (second raw material supply, reactant supply). An oxidant may be used as the reactant, for example. A catalyst may be supplied to the wafer 200 in at least one of the second raw material supply and reactant supply steps. The supply of the catalyst in both the second raw material supply and reactant supply steps will be explained below. [Second Raw Material Supply] In this step, valves 243d and 243f are opened to supply the second raw material and catalyst to wafer 200. At this time, valves 243g to 243i can also be opened to supply inert gas into processing chamber 201. By performing this step (supply of the second raw material) under the processing conditions described later, an adsorption layer of the second raw material can be formed in the recess with the first and second sacrificial membranes as sidewalls, and in at least a portion of the upper surfaces of the first and second sacrificial membranes respectively. The adsorption layer of the second raw material includes at least a portion of the molecular structure constituting the molecules of the second raw material. After the adsorption layer of the second raw material is formed, valves 243d and 243f are closed to stop the supply of the second raw material and catalyst to wafer 200. Then, through the above procedure, gaseous substances remaining in processing chamber 201 are removed from processing chamber 201, and inert gas is used to clean (clean) processing chamber 201. [Reactant Supply] In this step, valves 243b and 243f are opened to supply reactants and catalyst to wafer 200. At this time, valves 243g to 243i can also be opened to supply inert gas into processing chamber 201. By performing this step (reactant supply) under the processing conditions described later, the adsorption layer of the second raw material formed in the recess with the first and second sacrificial films as sidewalls, and at least a portion of the adsorption layer of the second raw material formed on the upper surfaces of the first and second sacrificial films respectively, can be modified. When an oxidant is used as the reactant, the adsorption layer of the second raw material can be oxidized, and an oxide layer containing the constituent elements of the second raw material can be formed in the recess with the first and second sacrificial films as sidewalls, and on at least a portion of the upper surfaces of the first and second sacrificial films respectively. After modifying the adsorption layer of the second raw material, valves 243b and 243f are closed to stop supplying reactants and catalysts to wafer 200. Then, through the above procedure, gaseous substances remaining in processing chamber 201 are removed from processing chamber 201, and processing chamber 201 is cleaned with inert gas. [Perform a predetermined number of times] Then, the cycle including the supply of the second raw material and the supply of the reactant will be performed a predetermined number of times (n). B Next, n B(Integers of 1 or 2 or higher). Thus, as shown in FIG4(c), an embedded film can be formed within the recess with the first and second sacrificial films as sidewalls, and on at least a portion of the upper surfaces of the first and second sacrificial films respectively. This cycle is performed until the recess is filled by the embedded film. When using a Si-containing material as the second raw material and an oxidant as the reactant, an oxide film, such as a silicon oxide film (SiO film), can be formed as the embedded film. As a second raw material, for example, the aforementioned alkylaminosilane, aminosilane, chlorosilane, and other Si-containing substances can be used. One or more of these can be used as the second raw material. As a reactant (oxidizing agent), oxygen (O2) can be used, for example. 2) Ozone (O 3) Water vapor (H 2O), nitrous oxide (N) 2O), nitric oxide (NO), nitrogen dioxide (NO) 2) Carbon dioxide (CO) 2) Carbon monoxide (CO), etc. One or more of these oxygen-containing (O) substances can be used as the reactant. Furthermore, in order to prevent the first and second sacrificial films from being substantially modified (oxidized) into oxide films by the reactant, it is preferable to use a reactant with weaker oxidizing power. For example, a reactant with weaker oxidizing power than the oxidant used in step E described later can be used. However, in cases where a reactant with strong oxidizing power can be used, such as when using a first and second sacrificial film with a composition that is difficult to oxidize, an oxidant with strong oxidizing power exemplified in step E described later can also be used. As a catalyst, pyridine (C) can be used, for example. 5H 5N), methylpyridine (C 6H 7N), dimethylpyridine (C 7H 9N), triethylamine ((C) 2H 5) 3N), etc. One or more of these amines can be used as catalysts. Examples of processing conditions for supplying the second raw material and catalyst in step B1 include: Processing temperature: room temperature (25°C) to 200°C, preferably room temperature to 150°C; Processing pressure: 1 to 2000 Pa, preferably 1 to 1333 Pa; Processing time: 1 to 180 seconds, preferably 10 to 120 seconds; Second raw material supply flow rate: 0.001 to 2 slm, preferably 0.01 to 1 slm; Catalyst supply flow rate: 0.001 to 2 slm, preferably 0.01 to 1 slm. Examples of processing conditions for supplying the reactants and catalyst in step B1 include: processing pressure: 1~4000 Pa, preferably 1~1333 Pa; reactant supply flow rate: 0.001~2 slm, preferably 0.01~1 slm; catalyst supply flow rate: 0.001~2 slm, preferably 0.01~1 slm; other processing conditions can be the same as those for supplying the second raw material and catalyst. After the formation of the embedded film on the surface of wafer 200 is completed, the processing chamber 201 is cleaned to remove any residual gases and reaction byproducts (post-cleaning). Then, the environment inside the processing chamber 201 is replaced with an inert gas (inert gas replacement) to restore the pressure inside the processing chamber 201 to atmospheric pressure (atmospheric pressure recovery). Afterward, the processed wafer 200 is moved outside the reaction tube 203 (crystal boat unloading) and removed from the crystal boat 217 (wafer release). Furthermore, after the crystal boat unloading, the lower opening of the manifold 209 is sealed using a baffle 219s (baffle closure). [Step B2: Separation film formation] Next, step B2 is performed on the wafer 200 after wafer release, that is, on the wafer 200 on which the embedded film has been formed on the surface. In step B2, the portion of the embedded film already formed on the surface of wafer 200, specifically the portion formed within the recess, is retained as a separation film, while the remaining portion is removed to expose at least a portion of the first and second sacrificial films. The removal of the embedded film portion can be performed, for example, by anisotropic etching using a plasma-excited etching gas, such as a fluorocarbon (CF)-based gas. Anisotropic etching can be performed, for example, using a first etching unit as a plasma etching apparatus, with known processing procedures and conditions. As a CF-based gas, for example, CF4200 can be used. 4. Gas, C 4F 6. Gas, C 4F 8 gases, CH 2F 2. Gases and CHF One or more of the following: gases, etc. Furthermore, the removal of the embedded film is not limited to the case where it is performed by anisotropic etching. In the case where the above-described adjacent structure is provided on a flat portion of the surface of wafer 200, the embedded film can also be partially removed by, for example, CMP (chemical mechanical polishing). By performing step B2, as shown in Figure 4(d), the surface of wafer 200 becomes a state where the first sacrificial film, the separation film, and the second sacrificial film are sequentially adjacent and exposed. The first sacrificial film and the second sacrificial film are physically separated (isolated) by the separation film. When the buried film is partially removed by anisotropic etching or CMP as described above, the exposed surfaces of the first sacrificial film, the separation film, and the second sacrificial film can become smooth surfaces (flat or curved surfaces) that are adjacent to each other without any step difference. Furthermore, as described above, the first and second sacrificial films are, for example, composed of nitrides such as SiN, and the separation film is, for example, composed of oxides such as SiO. Also, as described above, the first and second sacrificial films are formed under relatively low-temperature processing conditions, and are composed of nitrides with lower density compared to the first and third materials serving as substrates. That is, the first and second sacrificial films are composed of substances with different compositions from the components (separation film, first material, and third material) present around these films, or substances with the same composition but lower density, thus exhibiting a predetermined etching selectivity towards the surrounding components under given etching conditions, as described later. (Step C: Forming the first and second recesses) Next, step C is performed on the wafer 200 after a separation film is formed between the first and second sacrificial films. In step C, the first sacrificial film and the second sacrificial film are selectively removed relative to the separation membrane, the first material, and the third material. The selective removal of the first and second sacrificial films can be carried out by a known etching method that preferentially (selectively) etches the nitrides such as SiN constituting the first and second sacrificial films compared to the various substances constituting the separation membrane, the first material, and the third material. As an example of this method, hot phosphoric acid (H₂) can be used... 3PO 4. Wet etching using solutions of 70~90℃ and hydrogen fluoride as etchants; wet etching using nitrogen fluoride (NF) as an etchant. 3) Gases, fluorinated carbon (CF) 4) Dry etching using gas as the etchant. Such methods can be performed, for example, using a second etching unit as an etching apparatus. When the etch resistance of the first sacrificial film to the etchant is lower than that of the separation film and the first material to the etchant, and the etch resistance of the second sacrificial film to the etchant is lower than that of the separation film and the third material to the etchant, the first sacrificial film and the second sacrificial film can be selectively removed relative to the separation film, the first material, and the third material. By performing step C, as shown in FIG4(e), a first recess with one side of the separation film as a sidewall and the surface of the first material as a bottom surface, and a second recess with the other side of the separation film as a sidewall and the surface of the second material as a bottom surface, can be formed on the surface of wafer 200. In step D1 described later, the first and second recesses formed on the surface of wafer 200, i.e., the separation films constituting the sides of these recesses, can be suitably used as frames (molds for controlling the shape and size of the films formed inside the recesses) when forming films inside the recesses. Furthermore, the first and second recesses, i.e., the separation films constituting the sides of these recesses, can also be suitably used as separators (partitions) that physically and electrically separate the films formed inside the recesses from each other. Furthermore, in step A2, by forming the first sacrificial film to protrude towards one side of the surface of the second material from the boundary between the surface of the second material and the surface of the first material, the first recess can be formed in step C to protrude towards one side of the surface of the second material from the aforementioned boundary. Also, in step A2, by forming the second sacrificial film to protrude towards one side of the surface of the second material from the boundary between the surface of the second material and the surface of the third material, the second recess can be formed in step C to protrude towards one side of the surface of the second material from the aforementioned boundary. That is, in this embodiment, the first and second recesses can be formed such that the surfaces of the first and third materials are not covered by the separation film. (Step D) Next, the wafer 200 on which the first and second recesses have been formed on the surface is subjected to the following steps D1 and D2. The above-described loading procedure (wafer loading and wafer boat mounting ~ pressure adjustment and temperature adjustment) is performed again, and the wafer 200, which is an intermediate product obtained by performing steps A to C, is loaded into the processing chamber 201 again. After the pressure adjustment and temperature adjustment in the processing chamber 201 are completed, step D1 is started. [Step D1: Formation of dielectric film] In this step, the wafer 200 undergoes the following steps (third raw material supply, reactant supply). As a reactant, for example, an oxidant can be used. [Third Material Supply] In this step, valve 243e is opened to supply the third material to wafer 200. At this time, valves 243g to 243i can also be opened to supply inert gas into processing chamber 201. By performing this step (third material supply) under the processing conditions described later, an adsorption layer of the third material can be formed in at least a portion of the first and second recesses formed on the surface of the wafer 200 and on the upper surface of the separation film formed on the surface of the wafer 200. The adsorption layer of the third material contains at least a portion of the molecular structure constituting the molecules of the third material. After the adsorption layer of the third raw material is formed, valve 243e is closed to stop the supply of the third raw material to wafer 200. Then, through the above procedure, gaseous substances remaining in processing chamber 201 are removed from processing chamber 201, and inert gas is used to clean (clean) processing chamber 201. [Reactant Supply] In this step, valve 243b is opened to supply reactant to wafer 200. At this time, valves 243g to 243i can also be opened to supply inert gas into processing chamber 201. By performing this step (reactant supply) under the processing conditions described later, the adsorption layers of the third raw material formed in the first and second recesses, as well as the adsorption layers of the third raw material formed on at least a portion of the upper surface of the separation film formed on the surface of the wafer 200, can be modified respectively. When an oxidant is used as the reactant, the adsorption layers of the third raw material can be oxidized, and an oxide layer containing the constituent elements of the third raw material can be formed in at least a portion of the upper surface of the separation film formed in the first and second recesses and on the surface of the wafer 200. After modifying the adsorption layer of the third raw material, valve 243b is closed to stop supplying the reactant to wafer 200. Then, through the above procedure, gaseous substances remaining in processing chamber 201 are removed from processing chamber 201, and processing chamber 201 is cleaned with inert gas. [Perform a predetermined number of times] Then, the cycle including the supply of the third raw material and the supply of the reactant will be performed a predetermined number of times (n). D Next, n D (Integers of 1 or 2 or higher). Thus, as shown in FIG5(a), a membrane can be formed that is embedded in the first and second recesses and covers at least a portion of the upper surface of the separation membrane. This cycle continues until the dielectric membrane is embedded in the recesses. When using a metal-containing substance as the third raw material and an oxidant as the reactant, the membrane can be, for example, an oxide film such as an alumina film (AlO film), a titanium oxide film (TiO film), a hafnium oxide film (HfO film), or a zirconium oxide film (ZrO film), i.e., a dielectric film of a metal oxide film having a higher electron trap density than a SiN film. Furthermore, the dielectric film in this invention is not limited to an oxide film; a nitride film containing the same metal element can also be used as the dielectric film. However, when further implementing step E described later, it is preferable to use an oxide film as the dielectric film. As a third raw material, aluminum trichloride (AlCl3) can be used, for example. 3) Trimethylaluminum (Al(CH) 3) 3) Titanium tetrachloride (TiCl) 4) Hafnium tetrafluoride (HfF) 4) Tetra(ethylmethylamino)hafnium (Hf[N(CH)) 3)(CH 2CH 3)] 4) Zirconium tetrafluoride (ZrF) 4) Tetra(ethylmethylamino)zirconium (Zr[N(CH) 3)Cp] 4) etc. As a third raw material, such substances can be used, that is, substances (organometallic or metal halide) containing metallic elements such as aluminum (Al), titanium (Ti), hafnium (Hf), zirconium (Zr) can be used. As a reactant (oxidizing agent), one or more of the above-mentioned O-containing substances can be used. Examples of processing conditions for supplying the third raw material in step D1 include: Processing temperature: room temperature (25°C) to 700°C, preferably 350 to 550°C; Processing pressure: 1 to 2000 Pa, preferably 1 to 1333 Pa; Processing time: 1 to 180 seconds, preferably 10 to 120 seconds; Third raw material supply flow rate: 0.001 to 2 slm, preferably 0.01 to 1 slm; Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm. Examples of processing conditions for supplying the reactant in step D1 include: processing pressure: 1~4000 Pa, preferably 1~1333 Pa; reactant supply flow rate: 0.01~20 slm, preferably 0.01~10 slm; other processing conditions can be the same as those for supplying the third raw material. Furthermore, a nitriding agent can also be used as the reactant. One or more of the aforementioned nitrogen-containing substances can be used as the reactant. When using a silicon-containing substance as the third raw material and a nitriding agent as the reactant, a SiN film can be formed as a dielectric film. After step D1 is completed, the above removal procedure (post-cleaning ~ wafer release) is performed again, and the wafer 200 with a dielectric film formed on its surface is removed from the processing chamber 201 and taken out from the crystal boat 217. [Step D2: Forming the first dielectric film and the second dielectric film] Next, step D2 is performed on the wafer 200 after wafer release, that is, on the intermediate wafer 200 on which a dielectric film has been formed on the surface by step D1. In step D2, portions of the dielectric film formed on the surface of wafer 200 embedded in the first and second recesses are retained as the first and second dielectric films, respectively, while the remaining portions are removed. The partial removal of the dielectric film can be performed by various methods illustrated in step B2, such as anisotropic etching based on plasma-excited CF-based gas, CMP, etc. These methods can be performed, for example, using a first etching unit as a plasma etching apparatus. By performing step D2, as shown in Figure 5(b), the surface of wafer 200 becomes a state where the first dielectric film, the separation film, and the second dielectric film are sequentially adjacent and exposed. The first dielectric film and the second dielectric film are physically separated and electrically separated (isolated) by the separation film. When the dielectric films are partially removed by anisotropic etching and CMP as described above, the exposed surfaces of the first dielectric film, the separation film, and the second dielectric film can become smooth surfaces (flat or curved) that are adjacent to each other without any step difference. Furthermore, the electron trap density of the first dielectric film and the second dielectric film, which are composed of metal oxide films such as AlO films, is greater than that of a SiN film with the same thickness. Furthermore, in step C, by forming the first recess to protrude towards one side of the surface of the second material from the boundary between the surface of the second material and the surface of the first material, in step D2, the first dielectric film can be formed to protrude towards one side of the surface of the second material from the aforementioned boundary. Also, in step C, by forming the second recess to protrude towards one side of the surface of the second material from the boundary between the surface of the second material and the surface of the third material, in step D2, the second dielectric film can be formed to protrude towards one side of the surface of the second material from the aforementioned boundary. (Step E: Formation of the first and second displacement oxide films) Next, step E is performed on the wafer 200 after the first and second dielectric films have been formed on its surface. The above-described loading procedure (wafer loading and boat mounting ~ pressure adjustment and temperature adjustment) is performed again, and the wafer 200, which is an intermediate product obtained by performing steps A to D2, is loaded back into the processing chamber 201. After the pressure adjustment and temperature adjustment in the processing chamber 201 are completed, step E begins. In this step, valve 243b is opened to supply an oxygen-containing reactant (i.e., an oxidant) to wafer 200. At this time, valves 243g to 243i can also be opened to supply an inert gas into processing chamber 201. By performing step E under the processing conditions described later, a portion of the first material, which is in contact with the interface between the first material and the first dielectric film, can be modified (oxidized) towards the first substitution oxide film through the first dielectric film, and a portion of the third material, which is in contact with the interface between the third material and the second dielectric film, can be modified (oxidized) towards the second substitution oxide film through the second dielectric film. The first substitution oxide film and the second substitution oxide film are, for example, configured as SiO films and SiON films. Furthermore, in step E, the properties of the separation film, the first dielectric film, and the second dielectric film as oxide films can be further improved without impairing their characteristics. For example, the separation film, the first dielectric film, and the second dielectric film can be re-oxidized (additionally oxidized) to remove impurities from these films, thereby densifying the films and improving their insulation. After the above-mentioned modification is completed, valve 243b is closed to stop the supply of oxidant to the treatment chamber 201. Then, through the above procedure, gaseous substances remaining in the treatment chamber 201 are removed from the treatment chamber 201, and the treatment chamber 201 is cleaned with inert gas. As an oxidant, ozone (O2) can be used, for example. 3) O 2+hydrogen(H) 2) O 2+deuterium(D) 2) O 3+H 2. O 3+D 2. Hydrogen peroxide (H) 2O 2) O excited into a plasma state 2. O 3. Oxygen-containing substances. One or more of these substances can be used as oxidizing agents. Here, "O" is used. 2+H 2 」 The simultaneous recording of these two substances refers to O 2 and H A mixture of two substances. When supplying the mixture, the two substances can be mixed (premixed) in the supply pipe before being supplied to the processing chamber 201, or the two substances can be supplied separately to the processing chamber 201 from different supply pipes and mixed (postmixed) in the processing chamber 201. Furthermore, by adjusting the processing conditions, etc., if a first displacement oxide film and a second displacement oxide film separated by the first dielectric film and the second dielectric film can be formed, an oxidant with weaker oxidizing power, as exemplified in step B above, can also be used. Examples of processing conditions for supplying the oxidant in step E include: Processing temperature: room temperature 350–1000°C, preferably 400–650°C; Processing pressure: 1–105000 Pa, preferably 10–10000 Pa; Processing time: 1–10000 seconds, preferably 5–3600 seconds; Oxidant supply flow rate: 0.01–10 slm, preferably 0.1–5 slm; Inert gas supply flow rate (per gas supply pipe): 0–20 slm. (Step F: Forming tunnel oxide film and channel film) Next, step F is performed on the wafer 200 after the formation of the first substitution oxide film and the second substitution oxide film. In this step, a tunnel oxide film and a channel film are sequentially deposited on the surfaces of the separation film, the first dielectric film, and the second dielectric film formed on the wafer 200. The formation of the tunnel oxide film and the channel film can be performed using conventional and known methods as part of the manufacturing steps of the storage cells in flash memory. Furthermore, step F can be performed in the aforementioned processing chamber 201 where step E was performed (in situ), or it can be performed in the processing chamber of other substrate processing apparatus (not in situ). By performing steps A to F above, the laminated structure shown in Figure 5(d) is manufactured. This multilayer structure can preferably be used as part of the constituent elements of a flash memory cell. That is, the first and second dielectric films formed by the above method, being metal oxide films, have a higher electron trapping density than SiN films, and are precisely formed with high dimensional accuracy in an appropriate shape, thus they can be appropriately used as charge trapping layers in the memory cell. Furthermore, the separation film is composed of an oxide film such as SiO, and therefore can be appropriately used as a separation layer to insulate adjacent charge trapping layers in the flash memory cell. Also, the first and second displacement oxide films are composed of oxide films (SiO film and SiON film), and therefore can be appropriately used as barrier layers to suppress leakage from the charge trapping layers. (3) Effects of the original sample: Based on the original sample, one or more of the following effects can be obtained. (a) By performing steps A to C above, in a substrate having a structure in which the surfaces of the first to third materials are sequentially adjacent, recesses (first recess, second recess) can be selectively formed on the surface of a substrate made of specific materials (first material, third material). These recesses can be suitably used, for example, as frames (molds) for forming films inside them, or as separators (partitions) that physically and electrically separate the films formed inside them from each other. This allows for precise film formation on the substrate. Furthermore, if these recesses are used as frames and dielectric films are formed inside them, the films formed within the recesses can be suitably used as charge trapping layers for storage cells in flash memory. (b) By using at least one of the following: the second material is an oxide, and the first and third materials are oxides or non-oxides with a lower oxygen content than the second material, the aforementioned effect can be obtained more accurately. For example, the first and third materials are nitrides such as SiN, and the second material is an oxide such as SiO. This allows for the selective formation of OH terminals (hydroxyl terminals) on the surface of the second material (which is an oxide) to the selective formation of the first and second sacrificial films on the surfaces of the first and third materials, respectively. Furthermore, by using the aforementioned materials for the first to third materials, these sequentially adjacent structures can be appropriately used as part of the constituent elements of a storage cell, such as a flash memory. (c) By using an oxide film such as a SiO film as the separation membrane, the above-mentioned effects can be obtained more accurately. Furthermore, by using an oxide film such as a SiO film as the separation membrane, the membrane can be appropriately used as a separation layer for example, insulating adjacent charge trapping layers in the storage cells of flash memory. (d) In step A, by performing steps A1 and A2 as described above, the first sacrificial film and the second sacrificial film can be selectively formed on the surface of the second material efficiently. As a result, in the subsequent step C, the first recess and the second recess can be formed efficiently with high dimensional accuracy. (e) In step A, by forming the first sacrificial film to protrude from the boundary between the surface of the second material and the surface of the first material toward one side of the surface of the second material, and by forming the second sacrificial film to protrude from the boundary between the surface of the second material and the surface of the third material toward one side of the surface of the second material, the shape and size of the first and second recesses formed in step C can be appropriately adjusted. For example, by forming the first and second sacrificial films in step A as described above, the surfaces of the first and third materials are not covered by the separation film, and the first and second recesses can be formed. Therefore, the shape and size of the first dielectric film formed in the first recess and the second dielectric film formed in the second recess in step D can be set to a suitable shape and size when these films are used as charge trapping layers of a storage cell. (f) When performing steps B1 and B2 in step B, the separation membrane is formed using a recess with the first and second sacrificial membranes as sidewalls as a frame, allowing for high dimensional accuracy with good controllability. Furthermore, by covering at least a portion of the upper surface of each of the first and second sacrificial membranes with an embedded membrane in step B1 and removing unwanted portions of the embedded membrane in step B2, the separation membrane can be made into a gapless membrane embedded within the recess. This allows the separation membrane to be appropriately used, for example, as a separation layer that insulates adjacent charge-capturing layers. Furthermore, by constructing an embedded membrane from an oxide film such as a SiO film, the membrane obtained by processing the film can be appropriately used as a separation membrane, for example, a charge trapping layer. Furthermore, in step B1, by performing the cycle including the supply of the second raw material and the supply of the reactant a predetermined number of times, the embedded membrane can be formed in a well-controlled manner with a good step coverage. This improves the quality of the separation membrane, allowing the membrane obtained by processing it to be appropriately used as a separation membrane, for example, as a charge trapping layer. (g) In step D, by forming a first dielectric film in the first recess and a second dielectric film in the second recess, the first and second recesses can function as frames (molds) for forming the first and second dielectric films, respectively. This allows the shapes and sizes of the resulting first and second dielectric films to be tailored to, for example, the shape and size of a charge-trapping layer for a storage cell. Furthermore, a separation membrane, acting as an isolator (separator), can be formed between the first and second dielectric films to separate them. This allows, for example, when the first and second dielectric films are used as charge-trapping layers for a storage cell, electrical interference between the charge-trapping layers to be suppressed by the separation membrane. Furthermore, the first dielectric film and the second dielectric film each have a larger electron trap density than the silicon nitride film, thereby allowing these films to be appropriately used as charge trapping layers, for example, in storage cells. (h) In step D, by forming the first dielectric film and the second dielectric film according to the procedures of steps D1 and D2, the first dielectric film can be seamlessly embedded in the first recess and the second dielectric film can be seamlessly embedded in the second recess. As a result, these films can be appropriately used as, for example, charge trapping layers of a storage cell. (i) Since the first dielectric film and the second dielectric film are respectively oxide films such as metal oxide films, the first dielectric film and the second dielectric film can be appropriately used as charge trapping layers for example, storage cells. Furthermore, since the first dielectric film and the second dielectric film are respectively metal oxide films or other oxide films, when the first substitution oxide film and the second substitution oxide film are formed in step E, even if a portion of the first material and a portion of the third material are oxidized (modified) through the first dielectric film and the second dielectric film, the characteristics of these films as oxide films can be directly maintained. In contrast, for example, if the first dielectric film and the second dielectric film are nitride films, if a portion of the first material and a portion of the third material are oxidized through the first dielectric film and the second dielectric film, at least a portion of the nitrogen in the film may detach, making it difficult to maintain the characteristics of these films as nitride films. (j) After step D, by performing step E of supplying oxidant to wafer 200, a first substitutional oxide film and a second substitutional oxide film, which are oxide films with high insulation properties, can be formed in an adjacent manner to the first dielectric film and the second dielectric film. Furthermore, by modifying (oxidizing) the first dielectric film and the second dielectric film through the first dielectric film and the second dielectric film, the film quality of the first dielectric film and the second dielectric film can be improved, making these films, for example, more suitable as charge trapping layers for storage cells. (k) If the first dielectric film and the second dielectric film formed by the method of the present invention are used as, for example, films constituting the charge trapping layer of a storage cell, the performance of the flash memory device can be improved. (l) The first sacrificial film has lower etch resistance to the etchant used in step C than the first material has lower etch resistance to the etchant, and the second sacrificial film has lower etch resistance to the etchant than the third material has lower etch resistance to the etchant. In this way, in step C, etching of the surfaces of the first material and the third material can be suppressed, and the first recess and the second recess can be formed with high dimensional accuracy in a well-controlled manner. Furthermore, the first sacrificial film and the second sacrificial film are respectively composed of films containing predetermined elements such as Si, and at least one of nitrogen and carbon, thereby appropriately reducing the etch resistance of these films and effectively achieving the above-mentioned effects. (m) The above-mentioned effects can also be obtained by arbitrarily selecting a predetermined substance from the above-mentioned various modifiers, various first to third raw materials, various reactants (oxidizing agents, nitriding agents), and various inert gases. <Other Embodiments of the Invention> The embodiments of the present invention have been specifically described above. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from its spirit. For example, water vapor (H2O) can be supplied to the wafer 200 in the processing chamber 201 after step A2 (forming the first and second sacrificial films) and before starting step B1 (forming the embedded film). 2O), oxygen (O) 2) Oxidizing agents. In this case, the processing procedure and conditions can be set to be the same as those in the reaction body supply in step B1. Alternatively, after step A2 is performed and before step B1 is started, the wafer 200 can be removed from the processing chamber 201 and exposed to the atmosphere. Under these circumstances, the same effect as described above can be obtained. Furthermore, in such cases, before starting step B, the first adsorption barrier layer remaining on the surface of wafer 200 can be removed and / or rendered ineffective, allowing for efficient and high-quality formation of the embedded film in the subsequent step B1. Alternatively, for example, in step D, the wafer 200 after the first and second recesses are formed on its surface may also be subjected to: (d-1) step D1' of selectively forming a second adsorption barrier layer (second inhibitor layer) on the surface of the separation film relative to the respective surfaces of the first and third materials to prevent the adsorption of the third raw material gas, and (d-2) step D2' of forming a first dielectric film on the surface of the first material and a second dielectric film on the surface of the third material respectively by supplying the third raw material gas to the wafer 200. The processing procedures and conditions in step D1' can be the same as those in step A1 (forming the first adsorption barrier layer) described above. The processing procedures and conditions in step D2' can be the same as those in step D1 (forming the dielectric film) described above. In this case, the same effect as described above can be obtained. Furthermore, when proceeding in this manner, the first and second dielectric films can be formed selectively and efficiently relative to the surface of the separation membrane. Moreover, after forming the first and second dielectric films, step D2 for removing unwanted dielectric films can be omitted, thereby improving device productivity. Furthermore, in step D, if steps D1' and D2' are performed, it is preferable that step D2' is performed until the first dielectric film is embedded in the first recess and the second dielectric film is embedded in the second recess. By seamlessly embedding the first dielectric film in the first recess and the second dielectric film in the second recess, the first dielectric film and the second dielectric film can be appropriately used as charge trapping layers, for example, in a storage cell. Furthermore, for example, in the above-described embodiment, an example of using an O-containing substance as the reactant (oxidant) in step B1 was described as the reactant used in step D1. The present invention is not limited to this; an O-containing substance with strong oxidizing power, as exemplified as the oxidant in step E1, can be used as the reactant used in step D1. In this case, in step D1, the first material and the third material can be modified (oxidized) in parallel with the formation of the dielectric film to form the first substitution oxide film and the second substitution oxide film. That is, step E1 can be omitted or the processing time required for step E1 can be shortened. However, as in the above-described embodiment, when steps D1 and E1 are performed as separate steps, the thickness adjustment of the first substitution oxide film and the second substitution oxide film can be controlled effectively in step E1. The formulations used in each process are preferably prepared individually according to the processing requirements and recorded and stored in storage device 121c via telecommunication lines and external storage device 123. Furthermore, at the start of each process, the CPU 121a preferably selects a suitable formulation from the plurality of formulations recorded and stored in storage device 121c according to the processing requirements. This allows for the reproducible formation of membranes of various types, compositions, qualities, and thicknesses within the processing apparatus. It also reduces the operator's workload, avoids operational errors, and allows for the rapid initiation of each process. The above-mentioned recipes are not limited to newly made products; for example, they can also be prepared by modifying existing recipes already installed on the processing device. In the case of modifying a recipe, the modified recipe can also be installed on the processing device via a telecommunication line or a program containing the recipe. Alternatively, existing recipes already installed on the processing device can be directly modified by operating the input / output device 122 of the existing processing device. In the above examples, an example of film deposition processing using a batch processing apparatus that processes multiple substrates at a time has been described. The present invention is not limited to the above examples; for example, it can also be appropriately applied when performing film deposition processing using a monolithic processing apparatus that processes one or several substrates at a time. Furthermore, in the above examples, an example of film deposition processing using a processing apparatus with a hot-wall type furnace has been described. The present invention is not limited to the above examples; it can also be appropriately applied when performing film deposition processing using a processing apparatus with a cold-wall type furnace. Furthermore, the above-described example illustrates a series of processing steps up to A1, A2, and B1 performed continuously (in situ) within the same processing chamber of the same processing device, followed by steps D1 and E performed within the same processing chamber of the same processing device. The present invention is not limited to the above-described example. Any one of steps A1, A2, B1, D1, and E, and any other step, can be performed in different processing chambers (not in situ) of different processing devices, or separately in different processing chambers of the same processing device. When using such processing apparatus, each processing can be performed according to the same processing procedure and processing conditions as the above-described state and modified examples, and the same effect as the above-described state and modified examples can be obtained. The above-mentioned states and variations can be used in appropriate combinations. In this case, the processing procedures and conditions can be set to be the same as those in the above-mentioned states and variations. 115: Crystal boat elevator; 115s: Baffle opening and closing mechanism; 121: Controller; 121a: CPU; 121b: RAM; 121c: Memory device; 121d: I / O port; 121e: Internal bus; 122: Input / output device; 123: External memory device; 200: Wafer (substrate) 201: Processing Chamber; 202: Processing Furnace; 203: Reaction Tube; 207: Heater; 209: Manifold; 217: Crystal Boat; 218: Insulation Plate; 219: Sealing Cover; 219s: Baffle; 231: Exhaust Pipe; 231a: Exhaust Port; 232a, 232b, 232c, 232d, 232e, 232f, 232g, 232h, 232i: Gas Supply Pipes; 241a, 241b, 241c, 241d, 241e, 241f, 241g, 241h, 241i: Mass Flow Controller (MFC) 243a, 243b, 243c, 243d, 243e, 243f, 243g, 243h, 243i: Valve; 244: APC valve; 245: Pressure sensor; 246: Vacuum pump; 248: Accumulating supply system; 249a, 249b, 249c: Nozzle; 250a, 250b, 250c: Gas supply port; 263: Temperature sensor; 267: Rotary mechanism Figure 1 is a schematic diagram of the longitudinal processing furnace of a substrate processing apparatus applicable to one aspect of the present invention, that is, a longitudinal cross-sectional view showing a portion of the processing furnace 202. Figure 2 is a schematic diagram of the longitudinal processing furnace of a substrate processing apparatus applicable to one aspect of the present invention, that is, a cross-sectional view along line AA in Figure 1 showing a portion of the processing furnace 202. Figure 3 is a schematic diagram of the controller 121 of a substrate processing apparatus applicable to one aspect of the present invention, which is a block diagram showing the control system of the controller 121. Figure 4(a) shows a partial cross-sectional enlarged view of the surface portion of the wafer 200 in the first state of the present invention after step A1 of forming the first adsorption barrier layer on the surface of the second material; Figure 4(b) shows a partial cross-sectional enlarged view of the surface portion of the wafer 200 in the first state of the present invention after step A2 of forming the first sacrificial film on the surface of the first material and the second sacrificial film on the surface of the third material, respectively, from the state of Figure 4(a); Figure 4(c) shows the wafer 200 after step B1 of forming an embedded film on the wafer 200, from the state of Figure 4(b). Figure 4(d) shows a partial cross-sectional enlarged view of the surface portion of the wafer 200 in one embodiment of the present invention after step B2, which involves removing a portion of the embedded film to form a separation film on the wafer 200, starting from the state shown in Figure 4(c); Figure 4(e) shows a partial cross-sectional enlarged view of the surface portion of the wafer 200 in one embodiment of the present invention after step C, which involves removing the first sacrificial film and the second sacrificial film to form the first recess and the second recess on the wafer 200, starting from the state shown in Figure 4(d). Figure 5(a) shows a partial enlarged cross-sectional view of the surface portion of the wafer 200 in a sample of the present invention after step D1 of forming a dielectric film on the wafer 200, starting from the state shown in Figure 4(e); Figure 5(b) shows a partial enlarged cross-sectional view of the surface portion of the wafer 200 in a sample of the present invention after step D2 of removing a portion of the dielectric film and forming a first dielectric film in a first recess and a second dielectric film in a second recess, starting from the state shown in Figure 5(a); Figure 5(c) shows a partial enlarged cross-sectional view of the surface portion of the wafer 200 in a sample of the present invention after step E of modifying a portion of the first material to the first replacement oxide film and modifying a portion of the third material to the second replacement oxide film, starting from the state shown in Figure 5(b); Figure 5(d) shows a partial enlarged cross-sectional view of the surface portion of the wafer 200 in a sample of the present invention after step F of sequentially depositing a tunnel oxide film and a channel film on the wafer 200, starting from the state shown in Figure 5(b). 115: Crystal Boat Elevator 115s: Baffle opening and closing mechanism 121: Controller 200: Wafer (substrate) 201: Processing Room 202: Processing Furnace 203: Reaction tube 207: Heater 209: Manifold 217: Crystal Boat 218: Insulation board 219: Sealing Cap 219s: baffle 231: Exhaust pipe 231a: Exhaust port 232a, 232b, 232c, 232d, 232e, 232f, 232g, 232h, 232i: Gas supply pipes 241a, 241b, 241c, 241d, 241e, 241f, 241g, 241h, 241i: Mass Flow Controller (MFC) 243a, 243b, 243c, 243d, 243e, 243f, 243g, 243h, 243i: Valves 244: APC valve 245: Pressure sensor 246: Vacuum pump 248: Aggregated Supply System 249a, 249b, 249c: Nozzles 250a, 250b, 250c: Gas supply ports 263: Temperature sensor 267: Rotating mechanism

Claims

1. A substrate processing method comprising: (a) in a substrate having surfaces of a first material, a second material, and a third material sequentially adjacent to each other, selectively forming a first sacrificial film on the surface of the first material and a second sacrificial film on the surface of the third material, respectively, with respect to the surface of the second material; (b) forming a separation film in a recess having the first and second sacrificial films as sidewalls; and (c) selectively removing the first and second sacrificial films with respect to the separation film, the first material, and the third material, thereby forming a first recess having one sidewall of the separation film as a sidewall and the surface of the first material as a bottom surface, and a second recess having the other sidewall of the separation film as a sidewall and the surface of the second material as a bottom surface.

2. The substrate processing method as described in claim 1, wherein, The second material is an oxide, and the first material and the third material are at least one of oxides or non-oxides in which the oxygen content is lower than that of the second material.

3. The substrate processing method as described in claim 1, wherein, The first material and the third material are nitrides, and the second material is an oxide.

4. The substrate processing method as described in claim 1, wherein, The first material and the third material mentioned above are silicon nitride, and the second material mentioned above is silicon oxide.

5. The substrate processing method as described in any of claims 2 to 4, wherein, The separation membrane described above is an oxide membrane.

6. The substrate processing method as described in any of claims 2 to 4, wherein, The separation membrane mentioned above is a silicon oxide membrane.

7. The substrate processing method as described in claim 1, wherein, (a) has the steps of: (a-1) selectively forming a first adsorption barrier layer on the surface of the second material relative to the respective surfaces of the first material and the third material to prevent the adsorption of the first raw material; and (a-2) forming a first sacrificial film on the surface of the first material and a second sacrificial film on the surface of the third material by supplying the first raw material to the substrate.

8. The substrate processing method as described in claim 1, wherein, In (a), the first sacrificial film is formed such that the boundary between the surface of the second material and the surface of the first material protrudes to one side of the surface of the second material.

9. The substrate processing method as described in claim 1, wherein, (b) has the following steps: (b-1) forming an embedded membrane that is embedded in the recess and covers at least a portion of the upper surfaces of the first sacrificial membrane and the second sacrificial membrane; and (b-2) retaining the portion of the embedded membrane formed in the recess as the separation membrane and removing the other portion.

10. The substrate processing method as described in claim 1, wherein, It has the steps of (d) forming a first dielectric film in the first recess and forming a second dielectric film in the second recess.

11. The substrate processing method as described in claim 10, wherein, (d) includes: (d-1) the step of forming a dielectric film embedded in the first recess and the second recess and covering at least a portion of the upper surface of the separation membrane; and (d-2) the step of retaining the portions of the dielectric film embedded in the first recess and the second recess as the first dielectric film and the second dielectric film respectively, and removing the other portions.

12. The substrate processing method as described in claim 10, wherein, (d) includes: (d-1) the step of selectively forming a second adsorption barrier layer on the surface of the separation membrane to prevent the adsorption of the third raw material relative to the respective surfaces of the first material and the third material; and (d-2) the step of forming the first dielectric film on the surface of the first material and the second dielectric film on the surface of the third material respectively by supplying the third raw material to the substrate.

13. The substrate processing method as described in claim 10, wherein, The first dielectric film and the second dielectric film mentioned above are both oxide films.

14. The substrate processing method as described in claim 13, wherein, (e) After (d), by supplying an oxidant to the substrate, a portion of the first material in contact with the interface between the first material and the first dielectric film is modified to the first displacement oxide film through the first dielectric film.

15. The substrate processing method as described in claim 10, wherein, The first dielectric film and the second dielectric film mentioned above are respectively the charge trapping layer that constitutes the storage cell.

16. The substrate processing method as described in claim 1, wherein, The etch resistance of the etchant used in the first sacrificial film (c) is lower than that of the first material to the etchant, and the etch resistance of the second sacrificial film to the etchant is lower than that of the third material to the etchant.

17. A method for manufacturing a semiconductor device, comprising: (a) in a substrate having surfaces of a first material, a second material, and a third material sequentially adjacent to each other, selectively forming a first sacrificial film on the surface of the first material and a second sacrificial film on the surface of the third material, respectively, with respect to the surface of the second material; (b) forming a separation film in a recess having the first and second sacrificial films as sidewalls; and (c) selectively removing the first and second sacrificial films with respect to the separation film, the first material, and the third material, thereby forming a first recess having one sidewall of the separation film as a sidewall and the surface of the first material as a bottom surface, and a second recess having the other sidewall of the separation film as a sidewall and the surface of the second material as a bottom surface.

18. A program by which a computer causes a substrate processing apparatus to execute a predetermined program, the program being: (a) in a substrate having a structure in which the surfaces of a first material, a second material, and a third material are sequentially adjacent, a program selectively forming a first sacrificial film on the surface of the first material and a second sacrificial film on the surface of the third material, respectively, with respect to the surface of the second material; (b) a program forming a separation film in a recess with the first and second sacrificial films as sidewalls; (c) selectively removing the first and second sacrificial films with respect to the separation film, the first material, and the third material, thereby forming a first recess with one side of the separation film as a sidewall and the surface of the first material as a bottom surface, and a second recess with the other side of the separation film as a sidewall and the surface of the second material as a bottom surface.

19. A program for executing a predetermined program by means of a computer on a substrate processing apparatus used in the substrate processing method described in claim 1, wherein the program is: by supplying a first material to the substrate, a first sacrificial film is formed on the surface of the first material and a second sacrificial film is formed on the surface of the third material.

20. A substrate processing apparatus comprising: a modifier supply system configured to supply a modifier to a substrate having surfaces of a first material, a second material, and a third material sequentially adjacent to each other; a first raw material supply system configured to supply a first raw material to the substrate; a first reactant supply system configured to supply a first reactant to the substrate; a second raw material supply system configured to supply a second raw material to the substrate; a second reactant supply system configured to supply a second reactant to the substrate; an etchant supply system configured to supply an etchant to the substrate; and a control unit configured to control the modifier supply system, the first raw material supply system, the first reactant supply system, the second raw material supply system, the second reactant supply system, and the etchant supply system to perform: (a) By supplying the modifier to the substrate, a first adsorption barrier layer is selectively formed on the surfaces of the first material and the third material respectively, thereby hindering the adsorption of the first raw material. Then, by supplying the first raw material and the first reactant to the substrate, a first sacrificial film is selectively formed on the surface of the first material and a second sacrificial film is formed on the surface of the third material respectively, relative to the surface of the second material. (b) By supplying the second raw material and the second reactant to the substrate, a separation film is formed in a recess with the first sacrificial film and the second sacrificial film as sidewalls. (c) By supplying the etchant to the substrate, the first sacrificial film and the second sacrificial film are selectively removed relative to the separation film, the first material, and the third material, thereby forming a first recess with one side of the separation film as a sidewall and the surface of the first material as a bottom surface, and a second recess with the other side of the separation film as a sidewall and the surface of the second material as a bottom surface.

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