Processing method, method of manufacturing semiconductor device, processing apparatus, and program

Abstract

To provide a technique capable of improving productivity by efficiently etching the surface of a substrate.SOLUTION: (a) a step of arranging a product substrate and a nitrogen-containing substance in a processing container; and (b) a step of etching a surface of the product substrate by using a substance X generated by causing a chemical reaction between the nitrogen-containing substance and the product substrate by supplying a fluorine-containing substance into the processing container in a state where the product substrate and the nitrogen-containing substance are arranged.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] BACKGROUND ART As one step in the manufacturing process of a semiconductor device, a process of etching the surface of a substrate is sometimes performed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-137735 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that enables efficient etching of the surface of a substrate and increases productivity. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, (a) placing a product substrate and a nitrogen-containing material in a processing chamber; (b) supplying a fluorine-containing substance into the processing vessel in which the product substrate and the nitrogen-containing substance are placed, thereby causing a chemical reaction between the nitrogen-containing substance and the fluorine-containing substance to generate substance X, and etching the surface of the product substrate using the generated substance X; The present invention provides a technique having the following. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to efficiently etch the surface of a substrate and increase productivity. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic configuration diagram of a vertical processing furnace of a processing apparatus suitably used in the first embodiment of the present disclosure, showing a processing furnace 202 portion in vertical cross section. [Figure 2] FIG. 2 is a schematic configuration diagram of a vertical processing furnace of a processing apparatus suitably used in the first embodiment of the present disclosure, and is a cross-sectional view of the processing furnace 202 portion taken along line AA in FIG. [Figure 3] FIG. 3 is a schematic configuration diagram of the controller 121 of the processing device suitably used in the first embodiment of the present disclosure, and is a block diagram showing the control system of the controller 121. [Figure 4] FIG. 4 is a diagram showing a process flow according to the first embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram showing a process flow according to the second embodiment of the present disclosure. [Figure 6] Fig. 6(a) is a schematic diagram showing the state inside the processing vessel after performing step A in the first embodiment of the present disclosure. Fig. 6(b) is a schematic diagram showing the state inside the processing vessel after performing step A in the second embodiment of the present disclosure. [Figure 7] 4 is a schematic cross-sectional view showing the surface portion of the substrate after a film has been formed by performing a cycle including steps A to D multiple times. FIG. [Figure 8] FIG. 10 is a diagram showing the measurement results of the etching amount of a native oxide film on the surface of a substrate. DETAILED DESCRIPTION OF THE INVENTION

[0008] <First Aspect of the Present Disclosure> The first embodiment of the present disclosure will be described below mainly with reference to Figures 1 to 3, 4, and 6(a). Note that the drawings used in the following description are all schematic, and the dimensional relationships between elements, the ratios of elements, etc. shown in the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships between elements, the ratios of elements, etc. do not necessarily match between multiple drawings.

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

[0010] A reaction tube 203 is disposed concentrically with the heater 207 inside the heater 207. The reaction tube 203 is made of a heat-resistant material such as quartz (SiO2) or silicon carbide (SiC) and has a cylindrical shape with a closed upper end and an open lower end. A manifold 209 is disposed concentrically with the reaction tube 203 below the reaction tube 203. The manifold 209 is made of a metal material such as stainless steel (SUS) and has a cylindrical shape with open upper and lower ends. The upper end of the manifold 209 engages with the lower end of the reaction tube 203 and is configured to support the reaction tube 203. An O-ring 220a is provided between the manifold 209 and the reaction tube 203 as a sealing member. The reaction tube 203 is installed vertically, similar to the heater 207. The reaction tube 203 and the manifold 209 mainly constitute a processing vessel (reaction vessel). A processing chamber 201 is formed in the cylindrical hollow portion of the processing vessel. The processing chamber 201 is configured to be able to accommodate wafers 200 as product substrates. In the processing chamber 201, processing of the wafers 200 is performed.

[0011] Nozzles 249a to 249c serving as first to third supply units are respectively provided in the processing chamber 201 so as to penetrate the sidewall of the manifold 209. The nozzles 249a to 249c are also referred to as first to third nozzles, respectively. The nozzles 249a to 249c are made of a heat-resistant material such as quartz or SiC. Gas supply pipes 232a to 232c are connected to the nozzles 249a to 249c, respectively. The nozzles 249a to 249c are different nozzles, and each of the nozzles 249a and 249c is provided adjacent to the nozzle 249b.

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

[0013] As shown in FIG. 2, the nozzles 249a to 249c are respectively provided in an annular space between the inner wall of the reaction tube 203 and the wafers 200 in a plan view, extending from the lower part to the upper part of the inner wall of the reaction tube 203 and rising upward in the arrangement direction of the wafers 200. That is, the nozzles 249a to 249c are respectively provided in regions horizontally surrounding the wafer arrangement region on the sides of the wafer arrangement region where the wafers 200 are arranged, and extending along the wafer arrangement region. In a plan view, the nozzle 249b is disposed so as to face an exhaust port 231a (described later) on a straight line across the center of the wafer 200 in the processing chamber 201. The nozzles 249a and 249c are disposed so as to sandwich a line L passing through the nozzle 249b and the center of the exhaust port 231a along the inner wall of the reaction tube 203 (the outer periphery of the wafers 200) from both sides. The line L also passes through the nozzle 249b and the center of the wafer 200. In other words, the nozzle 249c can be said to be provided on the opposite side of the nozzle 249a across the line L. The nozzles 249a and 249c are arranged symmetrically with respect to the line L as the axis of symmetry. Gas supply holes 250a to 250c for supplying gas are provided on the side surfaces of the nozzles 249a to 249c, respectively. Each of the gas supply holes 250a to 250c opens to face (face) the exhaust port 231a in a plan view, and is able to supply gas toward the wafers 200. A plurality of the gas supply holes 250a to 250c are provided from the bottom to the top of the reaction tube 203.

[0014] A fluorine (F)-containing substance is supplied from the gas supply pipe 232a into the processing chamber 201 via the MFC 241a, the valve 243a, and the nozzle 249a.

[0015] From the gas supply pipe 232b, a raw material is supplied through the MFC 241b, the valve 243b, and the nozzle 249b into the processing chamber 201. The raw material is used as one of the film forming agents.

[0016] A dopant agent is supplied from the gas supply pipe 232c through the MFC 241c, the valve 243c, and the nozzle 249c into the processing chamber 201. The dopant agent is used as one of the film forming agents.

[0017] A reducing agent is supplied from the gas supply pipe 232d into the processing chamber 201 via the MFC 241d, the valve 243d, the gas supply pipe 232a, and the nozzle 249a.

[0018] A reactant is supplied from the gas supply pipe 232e through the MFC 241e, the valve 243e, the gas supply pipe 232b, and the nozzle 249b into the processing chamber 201. The reactant is used as one of the film forming agents.

[0019] Inert gas is supplied from the gas supply pipes 232f to 232h through the MFCs 241f to 241h, the valves 243f to 243h, the gas supply pipes 232a to 232c, and the nozzles 249a to 249c into the processing chamber 201. The inert gas acts as a purge gas, a carrier gas, a dilution gas, etc.

[0020] A fluorine-containing material supply system is mainly composed of the gas supply pipe 232a, MFC 241a, and valve 243a. A raw material supply system is mainly composed of the gas supply pipe 232b, MFC 241b, and valve 243b. A dopant agent supply system is mainly composed of the gas supply pipe 232c, MFC 241c, and valve 243c. A reducing agent supply system is mainly composed of the gas supply pipe 232d, MFC 241d, and valve 243d. A reactant supply system is mainly composed of the gas supply pipe 232e, MFC 241e, and valve 243e. An inert gas supply system is mainly composed of the gas supply pipes 232f-232h, MFCs 241f-241h, and valves 243f-243h. Some or all of the raw material supply system, dopant agent supply system, and reactant supply system are also referred to as film-forming agent supply systems. Either or both of the raw material supply system and the reactant supply system are also referred to as a coating agent (pre-coat agent) supply system.

[0021] Any or all of the various supply systems described above may be configured as an integrated supply system 248 in which the valves 243a-243h, MFCs 241a-241h, etc. are integrated. The integrated supply system 248 is connected to each of the gas supply pipes 232a-232h, and is configured so that the supply operation of various substances (various gases) into the gas supply pipes 232a-232h, i.e., the opening and closing operation of the valves 243a-243h and the flow rate adjustment operation by the MFCs 241a-241h, etc., are controlled by a controller 121, which will be described later. The integrated supply system 248 is configured as an integrated or separate integrated unit, and can be attached and detached to and from the gas supply pipes 232a-232h, etc., so that maintenance, replacement, expansion, etc. of the integrated supply system 248 can be performed on an integrated unit basis.

[0022] An exhaust port 231a for exhausting the atmosphere inside the processing chamber 201 is provided at the bottom of the sidewall of the reaction tube 203. As shown in FIG. 2, the exhaust port 231a is provided at a position facing (opposite) the nozzles 249a-249c (gas supply holes 250a-250c) across the wafer 200 in a plan view. The exhaust port 231a may be provided along the sidewall of the reaction tube 203 from the bottom to the top, i.e., along the wafer arrangement area. An exhaust pipe 231 is connected to the exhaust port 231a. A vacuum pump 246 serving as a vacuum exhaust device is connected to the exhaust pipe 231 via a pressure sensor 245 serving as a pressure detector (pressure detection unit) for detecting the pressure inside the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 serving as a pressure regulator (pressure adjustment unit). The APC valve 244 is configured to be able to evacuate and stop the evacuation of the processing chamber 201 by opening and closing the valve while the vacuum pump 246 is operating, and further, to be able to adjust the pressure inside the processing chamber 201 by adjusting the valve opening based on pressure information detected by the pressure sensor 245 while the vacuum pump 246 is operating. An exhaust system is mainly configured by the exhaust pipe 231, the APC valve 244, and the pressure sensor 245. The vacuum pump 246 may be included in the exhaust system.

[0023] Below the manifold 209, a seal cap 219 is provided as a furnace port cover capable of airtightly closing the lower end opening of the manifold 209. The seal cap 219 is made of a metal material such as SUS and is formed in a disk shape. An O-ring 220b is provided on the upper surface of the seal cap 219 as a sealing member that abuts against the lower end of the manifold 209. Below the seal cap 219, a rotation mechanism 267 is provided to rotate the boat 217 (described later). A rotation shaft 255 of the rotation mechanism 267 penetrates the seal cap 219 and is connected to the boat 217. The rotation mechanism 267 is configured to rotate the boat 217, thereby rotating the wafers 200. The seal cap 219 is configured to be vertically raised and lowered by a boat elevator 115 as a lifting mechanism installed outside the reaction tube 203. The boat elevator 115 is configured as a transfer device (transfer mechanism) that transfers (transports) the wafers 200 into and out of the processing chamber 201 by raising and lowering the seal cap 219, and functions as a device (preparation device) that places the product substrate and the nitrogen-containing material in the processing vessel. When the nitrogen-containing material is placed in the processing vessel by forming a nitride film (pre-coat film) in the processing vessel, as in the second embodiment described below, each part of the processing apparatus used in the process of forming the nitride film (such as a pre-coat agent supply system) and the boat elevator 115 that places the product substrate in the processing vessel function as the preparation device.

[0024] A shutter 219s is provided below the manifold 209 as a furnace port cover that can airtightly close the lower end opening of the manifold 209 when the seal cap 219 is lowered and the boat 217 is removed from the processing chamber 201. The shutter 219s is made of a metal material such as SUS and has a disk shape. An O-ring 220c is provided on the upper surface of the shutter 219s as a sealing member that abuts against the lower end of the manifold 209. The opening and closing operation (lifting and lowering operation, rotating operation, etc.) of the shutter 219s is controlled by a shutter opening and closing mechanism 115s.

[0025] The boat 217, serving as a substrate support, is configured to support multiple wafers (e.g., 25 to 200 wafers 200) in a horizontal position, aligned vertically with their centers aligned, and arranged in multiple stages, i.e., spaced apart. The boat 217 is also configured to support a predetermined number (one or more) of dummy wafers (non-product substrates) containing nitrogen and having a nitride film formed on their surfaces, similar to the wafers 200 serving as product substrates, in multiple stages. The boat 217 is also configured to support side dummy wafers and fill dummy wafers. The boat 217 is made of a heat-resistant material such as quartz or SiC. A heat insulating plate 218 made of a heat-resistant material such as quartz or SiC is supported in multiple stages at the bottom of the boat 217.

[0026] A temperature sensor 263 serving as a temperature detector is installed inside the reaction tube 203. By adjusting the power supply to the heater 207 based on the temperature information detected by the temperature sensor 263, the temperature inside the processing chamber 201 can be adjusted to a desired temperature distribution. The temperature sensor 263 is installed along the inner wall of the reaction tube 203.

[0027] As shown in FIG. 3, the controller 121, which is a control unit (control means), is configured as a computer including a CPU (Central Processing Unit) 121a, a RAM (Random Access Memory) 121b, a storage device 121c, and an I / O port 121d. The RAM 121b, the storage device 121c, and the I / O port 121d are configured to be able to exchange data with the CPU 121a via an internal bus 121e. An input / output device 122, such as a touch panel, is connected to the controller 121. An external storage device 123 can also be connected to the controller 121. The processing device may be configured to include one or more control units. That is, control for performing the processing sequence described below may be performed using one control unit or multiple control units. The multiple control units may be configured as a control system connected to each other via a wired or wireless communication network, and control for performing the processing sequence described below may be performed by the entire control system. In this specification, when the term "control section" is used, it may include one control section, multiple control sections, or a control system configured by multiple control sections.

[0028] The storage device 121c is configured with, for example, a flash memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), etc. Control programs for controlling the operation of the processing device, process recipes describing procedures and conditions for substrate processing (described later), etc., are readably recorded and stored in the storage device 121c. The process recipe is a combination of procedures for substrate processing (described later) that are executed by the controller 121 in the processing device to obtain a predetermined result, and functions as a program. Hereinafter, the process recipe, control program, etc. are collectively referred to simply as a program (program product). The process recipe is also simply referred to as a recipe. In this specification, the term "program" may refer to a recipe alone, a control program alone, or both. The RAM 121b is configured as a memory area (work area) for temporarily storing programs, data, etc. read by the CPU 121a.

[0029] The I / O port 121d is connected to the above-mentioned MFCs 241a to 241h, valves 243a to 243h, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotation mechanism 267, boat elevator 115, shutter opening / closing mechanism 115s, and the like.

[0030] The CPU 121a is configured to read and execute a control program from the storage device 121c, and to read a recipe from the storage device 121c in response to input of an operation command from the input / output device 122. The CPU 121a is configured to control, in accordance with the contents of the read recipe, the flow rate adjustment operation of various substances (various gases) by the MFCs 241a to 241h, the opening and closing operation of the valves 243a to 243h, the opening and closing operation of the APC valve 244 and the pressure adjustment operation by the APC valve 244 based on the pressure sensor 245, the start and stop of the vacuum pump 246, the temperature adjustment operation of the heater 207 based on the temperature sensor 263, the rotation and rotation speed adjustment operation of the boat 217 by the rotation mechanism 267, the lifting and lowering operation of the boat 217 by the boat elevator 115, the opening and closing operation of the shutter 219s by the shutter opening and closing mechanism 115s, and the like.

[0031] The controller 121 can be configured by installing the above-mentioned program recorded and stored in the external storage device 123 into a computer. The external storage device 123 includes, for example, a magnetic disk such as an HDD, an optical disk such as a CD, or a semiconductor memory such as a USB memory or an SSD. The storage device 121c and the external storage device 123 are configured as computer-readable recording media. Hereinafter, these will be collectively referred to as recording media. When the term recording media is used in this specification, it may include only the storage device 121c alone, only the external storage device 123 alone, or both. Note that the program may be provided to the computer using a communication means such as the Internet or a dedicated line, without using the external storage device 123.

[0032] (2) Treatment process An example of a method of processing a substrate (processing method) as one step in a semiconductor device manufacturing process (manufacturing method) using the processing apparatus described above, i.e., a processing sequence in which a processing sequence for etching the surface of a wafer 200 as a product substrate and a processing sequence for growing a film on the wafer 200 after etching are performed consecutively a predetermined number of times, will be described mainly with reference to FIG. 4. In the following description, the operation of each part constituting the processing apparatus is controlled by a controller 121. Note that the processing apparatus will also be referred to as a substrate processing apparatus, etching processing apparatus, etching apparatus, film formation processing apparatus, or film formation apparatus depending on the processing content. Also, the processing method will also be referred to as a substrate processing method, etching processing method, etching method, film formation processing method, or film formation method depending on the processing content.

[0033] In the processing sequence of this embodiment, (a) Step A in which a wafer 200 as a product substrate and a nitrogen (N)-containing material are placed in a processing chamber; (b) Step B of etching the surface of the wafer 200 by using a substance X generated by supplying an F-containing substance into a processing vessel in which the wafer 200 and the N-containing substance are placed, and causing a chemical reaction between the N-containing substance and the F-containing substance; Do the following.

[0034] In the following example, A case will be described in which the N-containing material placed in the processing chamber includes a dummy wafer as a non-product substrate having a nitride film formed on its surface.

[0035] Also, in the following example, after step B, (c) A case will be described in which step C is further performed in which a film is formed on the wafer 200 by supplying a film forming agent into the processing vessel in which the wafer 200 with its surface etched is placed.

[0036] Also, in the following example: Steps A to C are performed in a state where the wafer 200 is supported by a boat 217 as a support. (d) Step D is further performed outside the processing chamber, in which the wafers 200 are separated from the boat 217 to prevent the wafers 200 from sticking to the boat 217 due to the film formed in Step C; A case where a cycle including steps A to D is performed multiple times will be described.

[0037] The term "wafer" used in this specification may refer to the wafer itself or to a laminate of the wafer and a predetermined layer or film formed on its surface. The term "surface of a wafer" used in this specification may refer to the surface of the wafer itself or to the surface of a predetermined film or the like formed on the wafer. When described in this specification, "forming a predetermined film on the surface of a wafer" may mean forming a predetermined film directly on the surface of the wafer itself or forming a predetermined film on a film or the like formed on the wafer. When used in this specification, the term "substrate" is synonymous with the term "wafer".

[0038] The terms "agent" and "substance" used in this specification include at least one of a gaseous substance and a liquid substance. A liquid substance includes a mist substance. That is, each of the F-containing substance, the reducing agent, and the film-forming agent (raw material, dopant agent, reactant, etc.) may contain a gaseous substance, a liquid substance such as a mist substance, or both.

[0039] (Step A) First, a plurality of wafers 200 and dummy wafers having nitride films formed on their surfaces are loaded into the boat 217 (wafer charge).

[0040] Oxides may be formed on the surface of the wafer 200. Oxides are silicon oxide films (SiO xThe oxide may include at least one of a silicon oxide film (SiO2 film, where x is a real number less than 2) and a silicon oxide film (SiO2 film) of a stoichiometric composition. The oxide may also include at least one of a natural oxide film and a chemical oxide film. x The film and the SiO2 film are hereinafter also referred to collectively as the SiO film.

[0041] As the dummy wafer having a nitride film formed on its surface, a substrate having a film containing nitride such as silicon nitride (Si3N4, hereinafter also referred to as SiN) formed on its surface, i.e., a nitride film such as a silicon nitride film (SiN film), can be used. It is preferable that a predetermined number of dummy wafers are arranged between each wafer 200, i.e., every other product substrate, or every several product substrates. Hereinafter, for convenience, a dummy wafer having a SiN film formed on its surface will also be referred to as a SiN wafer.

[0042] After wafer charging is completed, the shutter 219s is moved by the shutter opening / closing mechanism 115s to open the lower end opening of the manifold 209 (shutter open). Thereafter, as shown in Fig. 1, the boat 217 supporting the wafers 200 and SiN wafers is lifted by the boat elevator 115 and loaded into the processing chamber 201 (boat loading). In this state, the seal cap 219 seals the lower end of the manifold 209 via the O-ring 220b.

[0043] 6(a), the wafer 200 as the product substrate and a non-product substrate (SiN wafer) having a nitride film formed on its surface as an N-containing material are placed in the process chamber 201. The SiN wafer as the non-product substrate is placed at a position adjacent to the wafer 200, but away from the wafer 200 as the product substrate.

[0044] (pressure and temperature regulation) After the boat loading is completed, the processing chamber 201, i.e., the space in which the wafers 200 are present, is evacuated (reduced pressure exhausted) by the vacuum pump 246 so that the interior of the processing chamber 201 is at a desired pressure (vacuum level). At this time, the pressure inside the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 244 is feedback-controlled based on the measured pressure information. Furthermore, the wafers 200 inside the processing chamber 201 are heated by the heater 207 so that the processing temperature is at a desired processing temperature. At this time, the power supply to the heater 207 is feedback-controlled based on temperature information detected by the temperature sensor 263 so that the processing chamber 201 has a desired temperature distribution. Furthermore, the rotation mechanism 267 starts to rotate the wafers 200. The evacuation inside the processing chamber 201 and the heating and rotation of the wafers 200 are all continued at least until the processing of the wafers 200 is completed.

[0045] (Step B) Thereafter, an F-containing substance is supplied into the processing chamber 201 in which the wafer 200 as the product substrate and the SiN wafer as the N-containing substance are placed.

[0046] Specifically, the valve 243a is opened to allow the F-containing substance to flow into the gas supply pipe 232a. The F-containing substance has a flow rate adjusted by the MFC 241a, is supplied into the processing chamber 201 via the nozzle 249a, and is exhausted from the exhaust port 231a. At this time, the F-containing substance is supplied to the wafer 200 and the N-containing material from the side of the wafer 200 and the N-containing material, and the wafer 200 and the N-containing material are exposed to the F-containing substance (F-containing substance supply, exposure). At this time, the valves 243f to 243h may be opened to supply an inert gas into the processing chamber 201 via the nozzles 249a to 249c, respectively.

[0047] By supplying an F-containing substance into the processing chamber 201 in which the wafer 200 and the N-containing material are placed under processing conditions described below, the N-containing material and the F-containing material are chemically reacted to generate a substance X. The substance X includes a substance generated in the process of etching the N-containing material placed in the processing chamber 201 with the F-containing substance, for example, a substance generated by decomposition of a reaction product generated in the process of etching the N-containing material with the F-containing substance. The substance X includes a substance containing nitrogen (N) and hydrogen (H). By generating the substance X in the processing chamber 201 to which the F-containing substance is supplied, it becomes possible to etch the surface of the wafer 200, i.e., oxides on the surface of the wafer 200, using the substance X.

[0048] For example, when the oxide on the surface of the wafer 200 placed in the processing chamber 201 includes silicon oxide (SiO), the N-containing material placed in the processing chamber 201 includes silicon nitride (SiN), and the F-containing material supplied into the processing chamber 201 includes hydrogen fluoride (HF), the reaction shown in the following formula can be caused to proceed under the conditions described below.

[0049] Si3N4+16HF → 3(NH4)2SiF6+2H2 (NH4)2SiF6 → SiF4+2HF+2NH3 SiO2+4HF+4NH3→ SiF4+2H2O+4NH3

[0050] That is, in the process chamber 201, a chemical reaction between an N-containing material (Si3N4) and an F-containing material (HF) can be caused to occur, generating a solid reaction product such as ammonium silicofluoride, i.e., ammonium hexafluorosilicate ((NH4)2SiF6). Furthermore, in the process chamber 201, this solid reaction product can be decomposed (e.g., thermally decomposed) to generate hydrogen nitride such as ammonia (NH3) as a substance X. By generating a substance X containing N and H, such as NH3, in the presence of an F-containing material (HF), an etching reaction of oxides (SiO2) present on the surfaces of the wafers 200 can be promoted in the process chamber 201, thereby removing the oxides from the surfaces of the wafers 200. Note that during the process of removing oxides using the F-containing material and the substance X, solid reaction products such as (NH4)2SiF6 may be generated again. However, in this reaction system, the solid reaction product is immediately decomposed once it is generated, resulting in the chain reaction described above. That is, in this reaction system, a chain reaction of reaction, generation of a solid reaction product, decomposition of the solid reaction product, and etching occurs repeatedly, making it possible to prevent the solid reaction product from remaining as a solid on the outermost surface of the oxide to be etched.

[0051] According to the present disclosure, as described above, it is possible to start the etching reaction without using the reaction between the F-containing substance (HF) and water (HO) as a trigger. That is, according to the present disclosure, it is possible to start the etching reaction and etch oxides on the surface of the wafer 200 without having HO present in the process chamber 201 at the start of step B.

[0052] After etching the surface of the wafer 200, the valve 243a is closed to stop the supply of the F-containing substance into the processing chamber 201. Then, the processing chamber 201 is evacuated to remove gaseous substances remaining in the processing chamber 201. At this time, the valves 243f to 243h are opened to supply an inert gas into the processing chamber 201 through the nozzles 249a to 249c. The inert gas supplied from the nozzles 249a to 249c acts as a purge gas, thereby purging the processing chamber 201 (purging). Note that the processing temperature during purging in this step is preferably the same as the processing temperature during supply of the F-containing substance.

[0053] At this time, the valve 243d may be opened to supply a reducing agent into the processing chamber 201 instead of or together with the inert gas. Also, at this time, cycle purging may be performed using the inert gas and / or the reducing agent. When cycle purging is performed, purging of the processing chamber 201 by supplying at least one of the inert gas and the reducing agent into the processing chamber 201 and evacuation (vacuum evacuation) of the processing chamber 201 may be alternately performed a predetermined number of times, preferably multiple times. Furthermore, in this case, while the processing chamber 201 is evacuated, supply of the reducing agent into the processing chamber 201 and supply of the inert gas into the processing chamber 201 may be alternately performed a predetermined number of times, preferably multiple times. Furthermore, in this case, while one of the inert gas and the reducing agent is continuously supplied into the processing chamber 201, supply of the other of the inert gas and the reducing agent into the processing chamber 201 and evacuation of the processing chamber 201 may be alternately performed a predetermined number of times, preferably multiple times. As a result, substances remaining in the processing chamber 201 can be efficiently and effectively exhausted and removed from the processing chamber 201. When an inert gas is used as the purge gas, the processing chamber 201 is purged mainly by a physical action. On the other hand, when a reducing agent is used as the purge gas, not only a physical action but also a chemical action can be generated, thereby further enhancing the purge effect. When performing cycle purging, the opening and closing of the valves 243f to 243h and the valve 243d is appropriately controlled in accordance with the supply timing of the inert gas and the reducing agent.

[0054] The processing conditions for supplying the F-containing substance in step B are as follows: Treatment temperature: room temperature (25°C) to 200°C, preferably 50 to 175°C, more preferably 100 to 150°C, and even more preferably 120 to 150°C Treatment pressure: 10 to 3000 Pa, preferably 10 to 2000 Pa Treatment time: 1 to 120 minutes, preferably 1 to 100 minutes F-containing substance supply flow rate: 0.5 to 3 slm, preferably 1 to 2 slm Inert gas supply flow rate (per gas supply pipe): 0 to 10 slm, preferably 1 to 5 slm is exemplified.

[0055] In this specification, when a numerical range such as "25 to 200°C" is expressed, it means that the lower limit and the upper limit are included in the range. Therefore, for example, "25 to 200°C" means "25°C or higher and 200°C or lower." The same applies to other numerical ranges. In this specification, the processing temperature means the temperature of the wafer 200 or the temperature inside the processing chamber 201, and the processing pressure means the pressure inside the processing chamber 201. The processing time means the time the processing continues. In addition, when the supply flow rate includes 0 slm, 0 slm means that the substance (gas) is not supplied. These also apply to the following explanations.

[0056] Here, if the processing temperature when supplying the F-containing substance in step B is set to be lower than room temperature (25°C), the etching rate can be increased. However, if other processing such as a film formation process is performed at least either before or after the etching process, the time required to change the processing temperature between the etching process and the other processing (temperature increase time and / or temperature decrease time) may become too long, which may result in a decrease in productivity.

[0057] By setting the processing temperature at or above room temperature (25°C), it is possible to maintain a high etching rate while shortening the time required to change the processing temperature between other processes, thereby suppressing a decrease in productivity. By setting the processing temperature at or above 50°C, it is possible to maintain a high etching rate while further shortening the time required to change the processing temperature between other processes, thereby suppressing a decrease in productivity. By setting the processing temperature at or above 100°C, it is possible to maintain a high etching rate while significantly shortening the time required to change the processing temperature between other processes, thereby significantly improving productivity. By setting the processing temperature at or above 120°C, it is possible to maintain a high etching rate while further significantly shortening the time required to change the processing temperature between other processes, thereby further significantly improving productivity.

[0058] Furthermore, if the processing temperature is set to a temperature higher than 200°C, the time required to change the processing temperature between other processes can be significantly reduced, but the etching rate may become too low, resulting in reduced productivity.

[0059] By setting the processing temperature at 200°C or less, it is possible to suppress a decrease in etching rate while maintaining a significant reduction in the time required for changing the processing temperature between other processes, thereby suppressing a decrease in productivity. By setting the processing temperature at 175°C or less, it is possible to further suppress a decrease in etching rate while maintaining a significant reduction in the time required for changing the processing temperature between other processes, thereby suppressing a decrease in productivity. By setting the processing temperature at 150°C or less, it is possible to significantly suppress a decrease in etching rate while maintaining a significant reduction in the time required for changing the processing temperature between other processes, thereby suppressing a decrease in productivity.

[0060] For the above reasons, the treatment temperature is preferably from room temperature (25°C) to 200°C, more preferably from 50°C to 175°C, more preferably from 100°C to 150°C, and even more preferably from 120°C to 150°C.

[0061] As the F-containing substance, for example, a substance containing hydrogen (H) such as hydrogen fluoride (HF) can be used. Also, as the F-containing substance, for example, fluorine (F2), nitrogen trifluoride (NF3), chlorine trifluoride (ClF3), chlorine fluoride (ClF), etc. can be used. As the F-containing substance, one or more of these can be used.

[0062] As the inert gas, nitrogen (N2) gas or a rare gas such as argon (Ar) gas, helium (He) gas, neon (Ne) gas, or xenon (Xe) gas can be used. One or more of these can be used as the inert gas. This also applies to each step described below.

[0063] As the reducing agent, for example, H-containing substances such as hydrogen (H2) and deuterium (D2) or deuterium (D)-containing substances can be used, and one or more of these can be used as the reducing agent.

[0064] After step B is completed, a bake process is performed in a reducing agent atmosphere as needed. Specifically, the output of the heater 207 is adjusted so that the temperature of the wafer 200 is maintained at the processing temperature of the bake process. Then, the valve 243d is opened to allow a reducing agent to flow into the gas supply pipe 232d. The reducing agent has its flow rate adjusted by the MFC 241d, is supplied into the processing chamber 201 via the gas supply pipe 232a and the nozzle 249a, and is exhausted from the exhaust port 231a. At this time, the reducing agent is supplied to the wafer 200 from the side of the wafer 200, and the wafer 200 is exposed to the reducing agent.

[0065] The processing conditions for the baking treatment are as follows: Treatment temperature: 700 to 1000°C, preferably 800 to 900°C Treatment pressure: 30 to 2000 Pa, preferably 30 to 1000 Pa Processing time: 30 to 120 minutes, preferably 30 to 90 minutes Reducing agent supply flow rate: 1 to 10 slm, preferably 1 to 5 slm Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm, preferably 1 to 10 slm is exemplified.

[0066] By supplying the reducing agent to the wafer 200 under the above-described processing conditions, substances, including by-products such as organic matter and moisture, remaining on the surface of the wafer 200 and in the processing chamber 201 can be reacted with the reducing agent and removed. At this time, if any substances that were not completely removed by the purging in step B remain on the surface of the wafer 200 or in the processing chamber 201, these substances can also be reacted with the reducing agent and removed. That is, this step can clean the surface of the wafer 200 and the inside of the processing chamber 201, and this clean state can be maintained until step C is performed. Note that if the surface of the wafer 200 and the inside of the processing chamber 201 can be kept clean after step B is performed and before step C is performed, the bake process may be omitted. FIG. 4 shows an example in which the bake process is omitted.

[0067] (Step C) After step B is completed or after the baking process is completed, the output of the heater 207 is adjusted so as to maintain the temperature of the wafer 200 at a predetermined processing temperature, which will be described later. Then, a raw material as a film forming agent and a reducing agent are supplied to the wafer 200.

[0068] Specifically, valves 243b and 243d are opened to allow the raw material and reducing agent to flow into gas supply pipes 232b and 232d, respectively. The raw material and reducing agent have their flow rates adjusted by MFCs 241b and 241d, are supplied into the processing chamber 201 via nozzles 249b and 249a, and are exhausted from the exhaust port 231a. At this time, the raw material and reducing agent are supplied to the wafer 200 from the side of the wafer 200, and the wafer 200 is exposed to the raw material and reducing agent (raw material + reducing agent supply, exposure). At this time, valves 243f to 243h may be opened to supply an inert gas into the processing chamber 201 via nozzles 249a to 249c, respectively.

[0069] By exposing the wafer 200 to a source material and a reducing agent under processing conditions described below, it is possible to form a predetermined film on the surface of the wafer 200 from which oxides have been removed. When the surface of the wafer 200 is made of single-crystal Si and when the source material and reducing agent described below are used, it is possible to grow and form an epitaxial Si film on the surface of the wafer 200. At this time, the action of the reducing agent can maintain the surface of the wafer 200 and the inside of the processing chamber 201 in a clean state, allowing epitaxial growth to proceed appropriately and forming a highly pure epitaxial Si film.

[0070] After forming a predetermined film on the surface of the wafer 200, the valves 243b and 243d are closed to stop the supply of the raw material and reducing agent into the processing chamber 201. Then, gaseous substances remaining in the processing chamber 201 are removed (purged) from the processing chamber 201 using the same processing procedure and conditions as those used for purging in step B. Note that the processing temperature during purging in this step is preferably the same as the processing temperature during the supply of the raw material and reducing agent.

[0071] The processing conditions for supplying the raw material and reducing agent in step C are as follows: Treatment temperature: 500 to 650°C, preferably 550 to 600°C Treatment pressure: 4 to 200 Pa, preferably 1 to 120 Pa Processing time: 10 to 120 minutes, preferably 20 to 60 minutes Raw material supply flow rate: 0.1 to 5 slm, preferably 0.2 to 3 slm Reducing agent supply flow rate: 1 to 20 slm, preferably 1 to 10 slm Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm, preferably 0.1 to 10 slm is exemplified.

[0072] The raw materials include, for example, monosilane (SiH4), disilane (Si2H6), trisilane (Si3H8), and tetrasilane (Si4H 10 Silicon hydrides such as tetrahydrofuran and tetrahydrofuran can be used.

[0073] As the reducing agent, for example, H-containing substances such as H2 and D2, or D-containing substances can be used. One or more of these can be used as the reducing agent.

[0074] (After purging and atmospheric pressure recovery) After step C is completed, an inert gas is supplied as a purge gas from each of the nozzles 249a to 249c into the processing chamber 201 and exhausted from the exhaust port 231a. This purges the processing chamber 201, and gases and reaction by-products remaining in the processing chamber 201 are removed from the processing chamber 201 (after-purge). Thereafter, the atmosphere in the processing chamber 201 is replaced with the inert gas (inert gas replacement), and the pressure in the processing chamber 201 is returned to normal pressure (atmospheric pressure return).

[0075] (Boat unloading) Thereafter, the seal cap 219 is lowered by the boat elevator 115, and the lower end of the manifold 209 is opened. Then, the processed wafers 200, supported by the boat 217, are carried out from the lower end of the manifold 209 to the outside of the reaction tube 203 (boat unloading). After the boat unloading, the shutter 219s is moved, and the lower end opening of the manifold 209 is sealed by the shutter 219s via the O-ring 220c (shutter closing).

[0076] (Step D) After the boat is unloaded, a process is performed outside the process chamber 201 to remove the wafers 200 from the boat 217 due to the film formed in step C. This process can be performed, for example, by temporarily separating (picking up) the wafers 200 from the boat 217. For example, this process can be performed by performing the reverse operation of loading the wafers 200 into the boat 217 during wafer charging. At this time, if the SiN wafers stick to the boat 217, the same process is performed on the SiN wafers. For example, the SiN wafers can be removed from the boat 217 by temporarily separating the SiN wafers from the boat 217 together with the wafers 200.

[0077] [Perform the specified number of times] A film of a desired thickness can be formed on the wafer 200 by performing a cycle including the above-described steps A to D a predetermined number of times (n times, where n is an integer of 1 or 2 or greater). This cycle is preferably performed multiple times. That is, as illustrated in FIG. 7, it is preferable to make the thickness of the film (each of the first and second films) formed by performing a cycle including steps A to D once thinner than the desired film thickness, and to repeat the above-described cycle multiple times until the thickness of the film stacked on the wafer 200 reaches the desired thickness. FIG. 7 shows an example in which this cycle was performed twice. In FIG. 7, the first film indicates the film formed in the first cycle, and the second film indicates the film formed in the second cycle. The dashed lines indicate the surface after oxides have been removed by etching in step B of each cycle. The dashed line between the wafer and the first film indicates the surface after oxides formed on the wafer surface have been removed by etching in step B of the first cycle. In addition, the dashed line between the first film and the second film indicates the surface after the oxide formed on the surface of the first film by removing the wafer 200 from the processing chamber 201 in step D of the first cycle has been removed by etching in step B of the second cycle.

[0078] When multiple cycles are performed, in wafer charging from the second cycle onward, the wafers 200 or SiN wafers temporarily removed from the boat 217 in step D are reloaded into the boat 217. When multiple cycles are performed, if the surface of a non-product substrate (SiN wafer) as an N-containing material loaded in the boat 217 after a certain cycle is covered with a film, it is preferable to replace this non-product substrate with a new non-product substrate (SiN wafer) having an exposed nitride film on its surface before starting the next cycle. When multiple cycles are performed, the non-product substrate can continue to be used as an N-containing material as long as the nitride film is exposed on at least a portion of its surface.

[0079] (wafer discharge) After a film of a desired thickness is formed on the wafer 200, the processed wafer 200 and the non-product substrate (SiN wafer) are removed from the boat 217 (wafer discharge).

[0080] This completes the processing steps in one aspect of the present disclosure.

[0081] It is preferable to perform the above-mentioned steps B and C in the same processing chamber (in-situ). If the series of processes is performed in-situ, the wafer 200 is not exposed to the atmosphere during the process, and stable processing can be performed consistently while the wafer 200 is kept under vacuum.

[0082] (3) Effects of this mode According to this aspect, one or more of the following effects can be obtained.

[0083] (a) In step A, a product substrate and an N-containing material are placed in a processing vessel, and in step B, an F-containing material is supplied into the processing vessel. This allows the surface of the product substrate to be etched using substance X, which is generated by chemically reacting the N-containing material with the F-containing material. The action of this substance X promotes the etching reaction, enabling efficient etching.

[0084] Furthermore, in step A, the product substrate and the N-containing material are placed in the processing vessel, and in step B, the F-containing material is supplied into the processing vessel. This allows the processing temperature for etching to be increased, and when other processes such as film formation processes are performed at least before or after the etching process, the processing temperature for etching can be made closer to the processing temperature for the other processes. This allows the time required to change the processing temperature between the etching process and the other processes, i.e., at least one of the temperature rise time and temperature fall time, to be shortened, thereby increasing productivity.

[0085] Furthermore, by increasing the etching temperature, solid reaction products generated during the reaction can be decomposed and removed while the F-containing substance is being supplied. This prevents the solid reaction products generated during the reaction from remaining on the outermost surface of the oxide to be etched, i.e., remaining solid, and preventing the reaction from proceeding further. This also eliminates the need to raise the processing temperature after stopping the supply of the F-containing substance and perform a separate process to sublimate the solid reaction products, thereby improving productivity.

[0086] (b) In steps A and B, the N-containing material is disposed at a position adjacent to the product substrate but away from the product substrate, thereby optimizing the location where substance X is generated so that it is not too close or too far from the product substrate and is a location where the etching reaction can be effectively caused, thereby making it possible to effectively obtain the above-mentioned effects.

[0087] (c) The above-mentioned effects can be obtained effectively when the N-containing material contains Si and the F-containing material contains H. Furthermore, the above-mentioned effects can be obtained even more effectively when the N-containing material contains SiN and the F-containing material contains HF.

[0088] (d) When substance X contains N and H, the above-mentioned effect can be obtained effectively. Furthermore, when substance X is a substance produced in the process of etching an N-containing material with an F-containing material, the above-mentioned effect can be obtained more effectively. Furthermore, when substance X is a substance produced by decomposition of a reaction product produced in the process of etching an N-containing material with an F-containing material, the above-mentioned effect can be obtained more effectively.

[0089] (e) In step B, the oxide on the surface of the product substrate is etched, thereby making it possible to effectively achieve the above-mentioned effects. Furthermore, if the oxide contains a silicon oxide film of a non-stoichiometric composition, the above-mentioned effects can be more effectively achieved. Furthermore, if the oxide contains at least one of a native oxide film and a chemical oxide film, the above-mentioned effects can be more effectively achieved.

[0090] (f) By setting the processing temperature in step B to 100°C or higher, it is possible to significantly shorten the time required to change the processing temperature between other processes while maintaining a high etching rate, thereby significantly improving productivity. In addition, by setting the processing temperature in step B to 100°C or higher, it is possible to effectively prevent solid reaction products generated during the etching reaction from remaining on the outermost surface of the oxide to be etched and preventing the reaction from proceeding further.

[0091] By setting the processing temperature in step B to 120°C or higher, it is possible to further significantly shorten the time required to change the processing temperature between other processes while maintaining a high etching rate, thereby further significantly improving productivity. In addition, by setting the processing temperature in step B to 120°C or higher, it is possible to more effectively prevent solid reaction products generated during the etching reaction from remaining on the outermost surface of the oxide to be etched and preventing the reaction from proceeding further.

[0092] (g) In step B, it is no longer necessary to use the reaction between the F-containing substance and HO as an etching trigger, and it is no longer necessary to adjust the processing vessel to have a trace amount of HO present at least at the start of step B. Furthermore, since it is no longer necessary to have a trace amount of HO present in the processing vessel at the start of step B, it is possible to increase the processing temperature in etching and also to maintain the inside of the processing vessel in a clean state.

[0093] (h) The above-mentioned effect can be effectively achieved by the N-containing material including a non-product substrate having a nitride film formed on its surface, and by placing the non-product substrate in the processing vessel one or more times every other product substrate in steps A and B. Furthermore, the N-containing material (non-product substrate having a nitride film formed on its surface) can be supported in the same manner as the product substrate by the support that supports the product substrate. This eliminates the need to provide a separate member for placing the N-containing material in the processing vessel. Furthermore, the N-containing material (non-product substrate having a nitride film formed on its surface) can be transported to the support using the same transport device as the product substrate, eliminating the need to provide a separate transport device for transporting the N-containing material.

[0094] (i) In step C, a film-forming agent is supplied into a processing vessel in which a product substrate with an etched surface is placed, and a film is formed on the product substrate, thereby making it possible to reduce the impurity concentration (oxygen concentration, etc.) at the interface between the product substrate and the film.

[0095] (j) By performing a cycle including steps A to D multiple times, it is possible to reduce the impurity concentration (oxygen concentration, etc.) at the interface between the product substrate and the film, and also to reduce the impurity concentration (oxygen concentration, etc.) at the interface between the film formed in the first cycle and the film formed in the second cycle.

[0096] (k) In step B, the N-containing material and the F-containing material are chemically reacted in the processing vessel to generate the substance X, so there is no need to install a separate supply line for supplying the substance X into the processing vessel, which reduces the cost of the equipment. In addition, the supply system can be simplified because the supply line for supplying the substance X can be omitted, which reduces the labor and cost required for maintaining the supply system.

[0097] (l) The above-mentioned effects can be similarly obtained when a predetermined substance is arbitrarily selected from the above-mentioned various F-containing substances, various film-forming agents, various reducing agents, and various inert gases.

[0098] <Second Aspect of the Present Disclosure> Next, the second embodiment of the present disclosure will be described mainly with reference to FIG. 5 and FIG. 6(b).

[0099] In this embodiment, the N-containing material placed in the processing chamber in steps A and B includes a nitride film formed in the processing chamber. In this respect, this embodiment differs from the first embodiment. Hereinafter, a processing sequence including step A (steps A1, A2, and A3) and step B in this embodiment will be described.

[0100] First, in a state where no wafer 200 is accommodated in the processing chamber 201, the pressure and temperature in the processing chamber 201 are adjusted as in the first embodiment described above, and then a process of forming a nitride film as a pre-coating film in the processing chamber 201, i.e., pre-coating, is performed (step A1). In step A1, a step of supplying a raw material as a pre-coating agent into the processing chamber 201 (raw material supply) and a step of supplying a reactant as a pre-coating agent into the processing chamber 201 (reactant supply) are sequentially performed a predetermined number of times.

[0101] To supply raw materials, valve 243b is opened to allow raw materials to flow into gas supply pipe 232b. The raw materials have their flow rate adjusted by MFC 241b, are supplied into processing chamber 201 through nozzle 249b, and are exhausted from exhaust port 231a. At this time, the surfaces of components in processing chamber 201 are exposed to the raw materials (raw material supply, exposure). At this time, valves 243f to 243h may be opened to supply an inert gas into processing chamber 201 through nozzles 249a to 249c, respectively.

[0102] After the raw material is supplied into the processing chamber 201 for a predetermined time, the valve 243b is closed to stop the supply of the raw material into the processing chamber 201. Then, gaseous substances remaining in the processing chamber 201 are removed from the processing chamber 201 (purged) using the same processing procedures and conditions as those for purging in step B of the first aspect described above.

[0103] To supply the reactant, valve 243e is opened to allow the reactant to flow into gas supply pipe 232e. The reactant has its flow rate adjusted by MFC 241e, is supplied into processing chamber 201 via nozzle 249b, and is exhausted from exhaust port 231a. At this time, the surfaces of components in processing chamber 201 are exposed to the reactant (reactant supply, exposure). At this time, valves 243f to 243h may be opened to supply an inert gas into processing chamber 201 via nozzles 249a to 249c, respectively.

[0104] After the reactant is supplied into the processing chamber 201 for a predetermined time, the valve 243e is closed to stop the supply of the reactant into the processing chamber 201. Then, gaseous substances remaining in the processing chamber 201 are removed from the processing chamber 201 (purged) using the same processing procedure and processing conditions as those for purging in step B of the first embodiment described above.

[0105] Then, by performing a cycle including the supply of raw materials and the supply of reactants a predetermined number of times (n times, where n is an integer of 1 or greater), a nitride film (pre-coated film) of a desired thickness is formed on the surfaces of components in the processing chamber 201, such as the inner wall of the reaction tube 203. The pre-coating may be performed with an empty boat 217 accommodated in the processing chamber 201. In this case, a nitride film (pre-coated film) of a desired thickness is formed on the surfaces of components in the processing chamber 201, such as the inner wall of the reaction tube 203 and the surface of the boat 217. When materials described below are used as the raw materials and the reactants, a silicon nitride film (SiN film) is formed as the nitride film on the surfaces of the components in the processing chamber 201.

[0106] The processing conditions when supplying the raw material in step A1 are as follows: Treatment temperature: 300 to 800°C, preferably 400 to 650°C Treatment pressure: 1 to 2000 Pa, preferably 1 to 1333 Pa Treatment time: 1 to 180 seconds, preferably 10 to 120 seconds 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, preferably 0.1 to 10 slm is exemplified.

[0107] The process conditions for supplying the reactants in step A1 are as follows: Treatment temperature: 300 to 800°C, preferably 400 to 650°C Treatment pressure: 1 to 4000 Pa, preferably 1 to 1333 Pa Treatment time: 1 to 180 seconds, preferably 10 to 120 seconds Reactant supply flow rate: 0.01 to 20 slm, preferably 0.01 to 10 slm Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm, preferably 0.1 to 10 slm is exemplified.

[0108] Examples of raw materials that can be used include chlorosilanes such as monochlorosilane (SiH3Cl), dichlorosilane (SiH2Cl2), trichlorosilane (SiHCl3), tetrachlorosilane (SiCl4), and hexachlorodisilane (Si2Cl6), as well as silicon hydrides exemplified as raw materials in step C of the first embodiment. One or more of these can be used as raw materials.

[0109] The reactant can be, for example, ammonia (NH), diazene (N2H2), hydrazine (N2H4), hydrogen nitride such as N3H8, etc. One or more of these can be used as the reactant.

[0110] After a nitride film of a desired thickness is formed on the surface of the components inside the processing chamber 201, after-purging and atmospheric pressure recovery are performed according to the same processing procedure as in the first embodiment described above.

[0111] Thereafter, a plurality of wafers 200 as product substrates are loaded (wafer charge) into the boat 217 (step A2) using the same processing procedure as in the first embodiment described above. Note that, unlike the first embodiment, in this embodiment, non-product substrates (SiN wafers) having nitride films formed on their surfaces are not loaded into the boat 217. Therefore, in this embodiment, the number of product substrates that can be processed at one time can be increased accordingly, thereby improving productivity.

[0112] After the wafer charging is completed, the boat 217 supporting the wafers 200 is loaded into the processing chamber 201 (boat loading) using the same processing procedure as in the first embodiment described above, and the wafers 200 are placed in the processing chamber 201 on which the nitride film has been formed (step A3). Upon completion of the boat loading, the processing chamber 201 is now in a state in which the wafers 200 as product substrates and the N-containing material (the nitride film formed on the surface of the component in the processing chamber 201) are placed, as shown in FIG. 6(b). As in the first embodiment described above, the N-containing material is placed at a position adjacent to the wafers 200, but away from the wafers 200.

[0113] The processing procedures and processing conditions in each step thereafter can be the same as those in the first embodiment. In step B, the surface of the product substrate can be etched using substance X generated by chemically reacting the nitride film formed on the surface of a member in the processing chamber 201, i.e., the inner wall of the reaction tube 203, with the F-containing substance. The action of this substance X promotes the etching reaction, enabling efficient etching, as in the first embodiment.

[0114] In this embodiment, a film of a desired thickness can be formed on the wafer 200 by performing a cycle including steps A to D a predetermined number of times (n times, where n is an integer of 1 or greater). If the nitride film formed on the surface of the component in the processing chamber 201 in step A1 is covered with a film after one cycle, a nitride film must be formed again (pre-coated) on the surface of the component in the processing chamber 201 before the next cycle. Therefore, a cycle including steps A (A1, A2, A3) to D must be performed a predetermined number of times. FIG. 6 shows an example in which pre-coating is performed every cycle. However, if the nitride film formed on the surface of the component in the processing chamber 201 is not entirely covered with a film after one cycle, but at least a portion of the nitride film is exposed, pre-coating is not necessary again. Alternatively, a cycle including steps A (A2, A3) to D may be performed a predetermined number of times. When performing multiple cycles, the nitride film formed on the surface of the component in the processing chamber 201 can be used as an N-containing material as long as at least a portion of the nitride film is exposed.

[0115] This embodiment also achieves the same effects as the first embodiment. Furthermore, according to this embodiment, the N-containing material can be formed on the surface of a component within the processing vessel, eliminating the need for a separate component for disposing the N-containing material within the processing vessel. Furthermore, according to this embodiment, it is not necessary to use non-product substrates with nitride films formed on their surfaces. This allows the support to be fully loaded with product substrates, increasing the number of product substrates processed at one time and improving productivity. Furthermore, according to this embodiment, the N-containing material can be conformally and uniformly formed on the surface of a component within the processing vessel, for example, the entire inner wall of the reaction tube 203. This allows substance X to be generated uniformly throughout the entire processing vessel, thereby improving the uniformity of the etching process.

[0116] <Other Aspects of the Present Disclosure> Although the embodiments of the present disclosure have been specifically described above, the present disclosure is not limited to the above embodiments and can be modified in various ways without departing from the spirit and scope of the present disclosure.

[0117] For example, in step B of the first and second aspects described above, the F-containing gas may be supplied intermittently, i.e., in a pulsed manner, into the processing vessel. For example, the supply of the F-containing gas into the processing vessel and the purging and / or evacuation of the processing vessel may be alternately performed a predetermined number of times (m times, where m is an integer of 1 or 2 or more). In this case, the same effects as those of the first and second aspects described above can be obtained. Furthermore, according to this aspect, by temporarily removing reaction products and residual gases from the processing vessel during etching to reset the reaction, it is possible to prevent excessive etching reactions and improve the controllability of the etching amount.

[0118] Furthermore, for example, in step C of the first and second aspects described above, a dopant agent may be supplied to the product substrate as a film-forming agent in addition to the raw materials and the reducing agent. The dopant agent can be supplied from the dopant agent supply system described above. The dopant agent can be a substance containing any of Group 15 elements such as phosphorus (P) and arsenic (As) and Group 13 elements such as boron (B). Examples of the dopant agent that can be used include phosphine (PH), arsine (AsH), diborane (BH), and trichloroborane (BCl). One or more of these can be used as the dopant agent. This aspect also achieves the same effects as the first and second aspects described above. Furthermore, this aspect enables the formation of a film doped with a dopant (P, As, B, etc.) on the product substrate.

[0119] Furthermore, for example, in step C of the first and second aspects described above, a semiconductor element-containing film may be formed on the product substrate using a substance containing a semiconductor element other than Si. For example, a germanium (Ge)-containing substance such as monogermane (GeH4) may be used as a raw material to form a Ge-containing film on the product substrate. Furthermore, for example, a Si-containing substance and a Ge-containing substance may be used as raw materials to form a Si- and Ge-containing film on the product substrate. Furthermore, for example, a substance containing a metal element such as tungsten (W), molybdenum (Mo), aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), or tantalum (Ta) may be used as a raw material to form a metal element-containing film on the product substrate. In these cases, the same effects as those of the first and second aspects described above can be obtained.

[0120] Furthermore, for example, in step C of the first and second aspects described above, an amorphous film, a polycrystalline film, or a mixed crystal film thereof may be formed on the product substrate in addition to an epitaxial film. In these cases, the same effects as those of the first and second aspects described above can be obtained.

[0121] Furthermore, for example, in the pre-coating (step A1) in step A of the second aspect described above, the raw material and the reactant may be simultaneously supplied into the processing vessel. In this aspect, the same effects as those in the first and second aspects described above can be obtained.

[0122] It is preferable that the recipes used for each process are individually prepared according to the process content and recorded and stored in the storage device 121c via an electric communication line or an external storage device 123. Then, when starting each process, it is preferable that the CPU 121a appropriately selects an appropriate recipe according to the process content from the multiple recipes recorded and stored in the storage device 121c. This enables the processing device to perform various processes with good reproducibility on films of various film types, composition ratios, film qualities, and film thicknesses. It also reduces the burden on the operator, prevents operational errors, and enables each process to be started quickly.

[0123] The above-mentioned recipes do not necessarily have to be newly created, but may be prepared by modifying an existing recipe that has already been installed in the processing device. When modifying a recipe, the modified recipe may be installed in the processing device via an electric communication line or a recording medium on which the recipe has been recorded. Alternatively, an existing recipe that has already been installed in the processing device may be directly modified by operating the input / output device 122 provided in the existing processing device.

[0124] In the above-described embodiment, an example of processing using a batch processing apparatus that processes multiple substrates at a time has been described. The present disclosure is not limited to the above-described embodiment and can be applied, for example, to processing using a single-wafer processing apparatus that processes one or several substrates at a time. Furthermore, in the above-described embodiment, an example of processing using a processing apparatus having a hot-wall processing furnace has been described. The present disclosure is not limited to the above-described embodiment and can be applied to processing using a processing apparatus having a cold-wall processing furnace.

[0125] In the above-described embodiment, the processing sequence is performed in the same processing chamber of the same processing apparatus (in-situ). The present disclosure is not limited to the above-described embodiment, and for example, one step and another step of the processing sequence may be performed in different processing chambers of different processing apparatuses (ex-situ), or may be performed in different processing chambers of the same processing apparatus.

[0126] When using these processing devices, each process can be performed using the same processing procedures and conditions as in the above-described embodiments and modifications, and the same effects as in the above-described embodiments and modifications can be obtained.

[0127] The above-described embodiments and modifications may be used in combination as appropriate. The processing procedures and processing conditions in such a case may be the same as those of the above-described embodiments and modifications, for example. [Example]

[0128] As an example, a Si wafer with a native oxide film formed on its surface and a Si wafer with a SiN film formed on its surface (hereinafter referred to as SiN wafer) were placed in a processing vessel with no nitride film formed inside, and HF gas was supplied into the processing vessel to etch the surface of the Si wafer. The etching amount was measured when the processing temperature during HF gas supply was set to 30, 50, 100, 150, and 200°C. Other processing conditions during HF gas supply were set to predetermined conditions within the processing condition range of step B of the above-mentioned embodiment.

[0129] As a comparative example, a Si wafer with a native oxide film formed on its surface was placed in a processing chamber without a nitride film formed inside, and HF gas was supplied into the processing chamber to etch the surface of the Si wafer. The etching amount was measured at processing temperatures of 30, 55, 75, and 100°C during HF gas supply. Other processing conditions during HF gas supply were the same as those in the example.

[0130] Figure 8 shows the results of measuring the etching depth of the native oxide film on the surface of a Si wafer. The horizontal axis of Figure 8 represents the processing temperature (°C) during HF gas supply, and the vertical axis represents the etching depth (au) of the native oxide film. The solid line in Figure 8 represents the measurement results of the etching depth of the native oxide film in the example, and the dashed line represents the measurement results of the etching depth of the native oxide film in the comparative example. As shown in Figure 8, the etching depth of the native oxide film in the example does not decrease at all until the processing temperature reaches 100°C. The decrease is slight even in the range of 100°C to 150°C. It can be seen that a sufficiently practical etching depth is obtained even in the range of 150°C to 175°C. In contrast, the etching depth of the native oxide film in the comparative example decreases significantly at temperatures above 55°C. In other words, according to the example, the etching of the native oxide film on the surface of a Si wafer can be efficiently performed at relatively high temperatures, significantly improving productivity. [Explanation of symbols]

[0131] 200 wafers (product substrates)

Claims

1. (a) placing a product substrate and a nitrogen-containing material in a processing chamber; (b) supplying a fluorine-containing substance into the processing vessel in which the product substrate and the nitrogen-containing substance are placed, thereby causing a chemical reaction between the nitrogen-containing substance and the fluorine-containing substance to generate substance X, and etching the surface of the product substrate using the generated substance X; A processing method comprising:

2. The method of claim 1 , wherein the nitrogen-containing material is disposed at a location adjacent to the product substrate but away from the product substrate.

3. The method of claim 1 , wherein the nitrogen-containing material comprises silicon and the fluorine-containing material comprises hydrogen.

4. 2. The method of claim 1, wherein the nitrogen-containing material comprises silicon nitride and the fluorine-containing material comprises hydrogen fluoride.

5. 5. The method of claim 4, wherein the substance X comprises nitrogen and hydrogen.

6. 2. The processing method according to claim 1, wherein the substance X is generated during etching of the nitrogen-containing substance by the fluorine-containing substance.

7. 2. The processing method according to claim 1, wherein the substance X is generated by decomposition of a reaction product produced in the process of etching the nitrogen-containing substance with the fluorine-containing substance.

8. 10. The method of claim 1, wherein step (b) etches oxide on the surface of the product substrate.

9. 9. The method of claim 8, wherein the oxide comprises a non-stoichiometric silicon oxide film.

10. The processing method according to claim 8 , wherein the oxide includes at least one of a natural oxide film and a chemical oxide film.

11. 2. The method according to claim 1, wherein the treatment temperature in step (b) is 100° C. or higher.

12. 2. The method according to claim 1, wherein the treatment temperature in step (b) is 120° C. or higher.

13. The fluorine-containing material and H ２ 2. The method of claim 1, wherein (b) is carried out under conditions that initiate etching without triggering a reaction with O.

14. The processing method according to any one of claims 1 to 13, wherein the nitrogen-containing material includes a non-product substrate having a nitride film formed on its surface.

15. 15. The processing method according to claim 14, wherein in steps (a) and (b), the non-product substrates are arranged in the processing vessel every other or every several product substrates.

16. The processing method according to any one of claims 1 to 13, wherein the nitrogen-containing material includes a nitride film formed in the processing vessel.

17. (a) is (a1) forming the nitride film in the processing chamber; (a2) placing the product substrate in the processing chamber on which the nitride film is formed; 17. The method of claim 16, comprising:

18. (c) supplying a film-forming agent into the processing vessel in a state in which the product substrate, the surface of which has been etched, is placed therein, thereby forming a film on the product substrate.

19. (a), (b), and (c) are performed in a state where the product substrate is supported by a support; (d) removing the product substrate from the support outside the processing chamber to prevent the film from adhering to the support; 20. The method of claim 18, wherein the cycle comprising (a), (b), (c), and (d) is performed multiple times.

20. (a) placing a product substrate and a nitrogen-containing material in a processing chamber; (b) supplying a fluorine-containing substance into the processing vessel in which the product substrate and the nitrogen-containing substance are placed, thereby causing a chemical reaction between the nitrogen-containing substance and the fluorine-containing substance to generate substance X, and etching the surface of the product substrate using the generated substance X; A method for manufacturing a semiconductor device having the above structure.

21. A processing vessel; an apparatus for placing a product substrate and a nitrogen-containing material in the processing vessel; a fluorine-containing material supply system for supplying a fluorine-containing material into the processing vessel; a control unit configured to be able to control the device and the fluorine-containing material supply system to perform the following processes: (a) a process of placing the product substrate and the nitrogen-containing material in the processing vessel; and (b) a process of supplying the fluorine-containing material into the processing vessel in which the product substrate and the nitrogen-containing material are placed, thereby causing a chemical reaction between the nitrogen-containing material and the fluorine-containing material to generate substance X, and etching the surface of the product substrate using the generated substance X; A processing device having:

22. (a) placing a product substrate and a nitrogen-containing material in a processing chamber; (b) supplying a fluorine-containing substance into the processing vessel in which the product substrate and the nitrogen-containing substance are placed, thereby causing a chemical reaction between the nitrogen-containing substance and the fluorine-containing substance to generate a substance X, and then etching the surface of the product substrate using the substance X; A program that causes a processing device to execute the above by a computer.

Images