Cleaning method, method of manufacturing semiconductor device, substrate processing apparatus, and program product

Abstract

The invention provides a cleaning method, a method of manufacturing a semiconductor device, a substrate processing apparatus, and a program product. This method for cleaning the inside of a processing container comprises: (a) a step of supplying a first gas containing a fluorine-based gas at a first flow rate into the processing container at a first temperature after processing a substrate and discharging the first gas to remove substances adhering to the inside of the processing container; (b) a step in which a second gas that does not chemically react with fluorine at a second temperature is supplied into the processing container at the second temperature higher than the first temperature after the step (a) at a second flow rate higher than both the first flow rate and the third flow rate, and the second gas is discharged, thereby physically removing and removing residual fluorine in the processing container; and (c) supplying a third gas, which chemically reacts with fluorine at a third temperature, at a third flow rate into the processing container at a third temperature higher than the first temperature after the step (a), and discharging the third gas to chemically remove and remove residual fluorine in the processing container.

Description

[0001] This application is a divisional application of a Chinese patent application with the original application date of September 11, 2019, application number 201910860140.9, and invention title "Cleaning Method, Manufacturing Method of Semiconductor Device, Substrate Processing Apparatus, and Recording Medium". Technical Field

[0002] The present invention relates to a cleaning method, a manufacturing method of a semiconductor device, a substrate processing apparatus, and a recording medium. Background Art

[0003] As one of the manufacturing processes of a semiconductor device, sometimes after substrate processing in which a film is formed on a substrate, a gas containing a fluorine-based gas is supplied into a processing container to perform a cleaning process on the inside of the processing container (for example, see Patent Document 1). In this case, if the next substrate processing is performed in the cleaned processing container, the productivity will decrease.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2012 - 311929 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] An object of the present invention is to provide a technique capable of performing the next substrate processing without reducing productivity after cleaning the inside of a processing container.

[0009] Means for Solving the Problems

[0010] According to one embodiment of the present invention, there is provided a cleaning method for cleaning the inside of a processing container by performing the following steps:

[0011] (a) A step of supplying a first gas containing a fluorine-based gas at a first flow rate into the processing container at a first temperature after processing the substrate and exhausting the gas to remove substances attached to the inside of the processing container.

[0012] (b) A step of supplying a second gas that does not chemically react with fluorine at a second temperature higher than the first temperature into the processing container at a second flow rate higher than both the first flow rate and a third flow rate after performing (a) and exhausting the gas to physically detach and remove residual fluorine in the processing container, and

[0013] (c) A step of supplying a third gas that chemically reacts with fluorine at the third temperature into the processing container at the third temperature higher than the first temperature after (a), exhausting the gas, and chemically removing and eliminating the residual fluorine in the processing container.

[0014] Advantages of the Invention

[0015] According to the present invention, after cleaning the inside of the processing container, the subsequent substrate processing can be performed without reducing the productivity. Description of the Drawings

[0016]

Figure 1 [[ID=13

[0017]

Figure 2 [[ID=18

[0018]

Figure 3 [[ID=25

[0019]

Figure 4 [[ID=30

[0020]

Figure 5 [[ID=35

[0021]

Figure 6 [[ID=40

[0022] Reference Signs

[0023] 200: Wafer (substrate). Detailed Description of the Invention

[0024]

[0025] Hereinafter, a preferred embodiment of the present invention will be described with reference to Figures 1 to 4 .

[0026] (1) Configuration of the substrate processing apparatus

[0027] As Figure 1 shown in the figure, the processing furnace 202 has a heater 207 as a heating mechanism (temperature adjustment unit). The heater 207 is cylindrical in shape and is vertically installed by being supported by a holding plate. The heater 207 also functions as an activation mechanism (excitation unit) that activates (excites) a gas by heat.

[0028] A reaction tube 203 is arranged 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 is formed in a cylindrical shape with the upper end closed and the lower end open. A manifold 209 is arranged 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 is formed in a cylindrical shape with both the upper end and the lower end open. The upper end portion of the manifold 209 is joined to the lower end portion of the reaction tube 203, and is configured to support the reaction tube 203. An O-ring 220a as a sealing member is provided between the manifold 209 and the reaction tube 203. The reaction tube 203 is vertically installed in the same manner as the heater 207. The processing container (reaction container) is mainly composed of the reaction tube 203 and the manifold 209. A processing chamber 201 is formed in the cylindrical hollow portion of the processing container. The processing chamber 201 is configured to be able to accommodate a wafer 200 as a substrate. The wafer 200 is processed in the processing chamber 201.

[0029] Nozzles 249a and 249b, which are respectively a first supply unit and a second supply unit, are provided in the processing chamber 201 to penetrate the side wall of the manifold 209. The nozzles 249a and 249b are also referred to as the first nozzle and the second nozzle. The nozzles 249a and 249b are made of a heat-resistant material such as quartz or SiC, for example. The nozzles 249a and 249b are respectively connected to gas supply pipes 232a and 232b. The nozzles 249a and 249b are different nozzles.

[0030] In the gas supply pipes 232a and 232b, mass flow controllers (MFCs) 241a and 241b as flow controllers (flow control units) and valves 243a and 243b as switching valves are provided in order from the upstream side of the gas flow, respectively. Gas supply pipes 232c and 232e are respectively connected to the downstream side of the valve 243a in the gas supply pipe 232a. Gas supply pipes 232d and 232f are respectively connected to the downstream side of the valve 243b in the gas supply pipe 232b. In the gas supply pipes 232c to 232f, MFCs 241c to 241f and valves 243c to 243f are provided in order from the upstream side of the gas flow, respectively. The gas supply pipes 232a to 232f are made of a metal material such as stainless steel (SUS), for example.

[0031] As Figure 2 shown, the nozzles 249a and 249b are respectively arranged to stand upright from the lower part of the inner wall of the reaction tube 203 along the upper part in a space that is annular in plan view between the inner wall of the reaction tube 203 and the wafer 200, toward the upper side in the arrangement direction of the wafers 200. That is, in the region on the side of the wafer arrangement region where the wafers 200 are arranged and horizontally surrounding the wafer arrangement region, the nozzles 249a and 249b are respectively arranged along the wafer arrangement region. Gas supply holes 250a and 250b for supplying gas are respectively provided on the side surfaces of the nozzles 249a and 249b. The gas supply holes 250a and 250b can supply gas to the wafer 200. A plurality of gas supply holes 250a and 250b are provided from the lower part to the upper part of the reaction tube 203.

[0032] For example, a halogenated silane-based gas containing Si and a halogen as a predetermined element (main element) constituting a film is supplied from the gas supply pipe 232a into the processing chamber 201 via the MFC 241a, the valve 243a, and the nozzle 249a as a raw material (raw material gas). The raw material gas refers to a raw material in a gaseous state. For example, a gas obtained by vaporizing a raw material that is in a liquid state at normal temperature and pressure, a raw material that is in a gaseous state at normal temperature and pressure, etc. A halogenated silane refers to a silane having a halogen group. The halogen group includes a chlorine group, a fluorine group, a bromine group, an iodine group, etc. That is, the halogen group contains halogens such as chlorine (Cl), fluorine (F), bromine (Br), and iodine (I). As the halogenated silane-based gas, for example, a raw material gas containing Si and Cl, that is, a chlorosilane-based gas can be used. The chlorosilane-based gas functions as a Si source. As the chlorosilane-based gas, for example, hexachlorodisilane (Si2Cl6, abbreviation: HCDS) gas can be used. The HCDS gas is a gas containing an element (Si) that becomes a solid by itself under the processing conditions described later, that is, a gas that can deposit a film by itself under the processing conditions described later.

[0033] A hydrogen nitride-based gas, such as a nitrogen (N)-containing gas, as a reaction body (reaction gas) is supplied from the gas supply pipe 232b into the processing chamber 201 via the MFC241b, the valve 243b, and the nozzle 249b. The hydrogen nitride-based gas acts as a nitriding gas, that is, an N source. For example, ammonia (NH3) gas can be used as the hydrogen nitride-based gas. The NH3 gas is a gas containing an element (N) that does not become solid alone under the processing conditions described later, that is, a gas that cannot deposit a film alone under the processing conditions described later.

[0034] A fluorine-based gas is supplied from the gas supply pipe 232c into the processing chamber 201 via the MFC241c, the valve 243c, the gas supply pipe 232a, and the nozzle 249a. For example, fluorine (F2) gas can be used as the fluorine-based gas.

[0035] A nitrogen oxide-based gas is supplied from the gas supply pipe 232d into the processing chamber 201 via the MFC241d, the valve 243d, the gas supply pipe 232b, and the nozzle 249b. The nitrogen oxide-based gas does not exert a cleaning effect alone, but reacts with the fluorine-based gas to generate active species such as, for example, fluorine radicals and nitrosyl fluoride compounds, and serves to enhance the cleaning effect of the fluorine-based gas. For example, nitric oxide (NO) gas can be used as the nitrogen oxide-based gas.

[0036] A non-reactive gas, such as nitrogen (N2) gas, is supplied from the gas supply pipes 232e and 232f into the processing chamber 201 via the MFC241e and 241f, the valves 243e and 243f, the gas supply pipes 232a and 232b, and the nozzles 249a and 249b. The N2 gas acts as a purge gas, a carrier gas, a dilution gas, or the like.

[0037] The raw material supply system mainly consists of the gas supply pipe 232a, the MFC241a, and the valve 243a. The reaction body supply system mainly consists of the gas supply pipe 232b, the MFC241b, and the valve 243b. The fluorine-based gas supply system mainly consists of the gas supply pipe 232c, the MFC241c, and the valve 243c. The nitrogen oxide-based gas supply system mainly consists of the gas supply pipe 232d, the MFC241d, and the valve 243d. The non-reactive gas supply system mainly consists of the gas supply pipes 232e and 232f, the MFC241e and 241f, and the valves 243e and 243f.

[0038] It should be noted that in the subsequent stage A, the fluorine-based gas supply system functions as a first gas supply system for supplying a first gas containing a fluorine-based gas into the processing container. In stage A, as the first gas, a fluorine-based gas and a nitrogen oxide-based gas can be mixed and used in the processing container. Therefore, it is also possible to consider including the nitrogen oxide-based gas supply system in the first gas supply system. In addition, in the subsequent stage B, the inert gas supply system functions as a second gas supply system for supplying a second gas that does not chemically react with fluorine at the second temperature described later. In addition, in the subsequent stage C, the nitrogen oxide-based gas supply system functions as a third gas supply system for supplying a third gas that chemically reacts with fluorine at the third temperature described later.

[0039] Among the above various supply systems, any one or all of the supply systems can be configured as an integrated supply system 248 formed by integrating valves 243a to 243f, MFCs 241a to 241f, etc. The integrated supply system 248 is configured to be connected to the gas supply pipes 232a to 232f respectively, and the operation of supplying various gases into the gas supply pipes 232a to 232f is controlled by a controller 121 described later, that is, the opening and closing operations of the valves 243a to 243f, the flow rate adjustment operations performed by the MFCs 241a to 241f, etc. The integrated supply system 248 is configured as a single-type or split-type integrated unit, and can be installed and disassembled with the gas supply pipes 232a to 232f, etc. in units of the integrated unit, and is configured to be able to perform maintenance, replacement, addition, etc. of the integrated supply system 248 in units of the integrated unit.

[0040] Below the side wall of the reaction tube 203, an exhaust port 231a for exhausting the atmosphere in the processing chamber 201 is provided. The exhaust port 231a can also be provided along the upper part from the lower part of the side wall of the reaction tube 203, that is, along the wafer arrangement area. The exhaust port 231a is connected to the exhaust pipe 231. The exhaust pipe 231 is made of a metal material such as SUS, for example. The exhaust pipe 231 is connected to a vacuum pump 246 as a vacuum exhaust device via a pressure sensor 245 as a pressure detector (pressure detection unit) for detecting the pressure in the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 as a pressure regulator (pressure adjustment unit). The APC valve 244 is configured to be able to perform vacuum exhaust and stop of vacuum exhaust in the processing chamber 201 by switching the valve in a state where the vacuum pump 246 is operating, and further, to be able to adjust the pressure in the processing chamber 201 by adjusting the valve opening based on the pressure information detected by the pressure sensor 245 in a state where the vacuum pump 246 is operating. The exhaust system mainly consists of the exhaust pipe 231, the APC valve 244, and the pressure sensor 245. It is also possible to consider including the vacuum pump 246 in the exhaust system.

[0041] Below the manifold 209, a sealing cap 219 is provided as a furnace port cover body that can airtightly block the lower end opening of the manifold 209. The sealing cap 219 is made of a metal such as SUS, for example, and is formed in a disc shape. On the upper surface of the sealing cap 219, an O-ring 220 as a sealing member that abuts against the lower end of the manifold 209 is provided. Below the sealing cap 219, a rotating mechanism 267 for rotating a wafer cassette 217 described later is provided. The rotating shaft 255 of the rotating mechanism 267 is made of a metal material such as SUS and penetrates the sealing cap 219 to be connected to the wafer cassette 217. The rotating mechanism 267 is configured to rotate the wafer 200 by rotating the wafer cassette 217. The sealing cap 219 is configured to be able to move up and down in the vertical direction by means of a wafer cassette elevator 115 as a lifting mechanism provided outside the reaction tube 203. The wafer cassette elevator 115 is configured to be able to carry the wafer 200 into the processing chamber 201 and carry it out (transfer) outside the processing chamber 201 by lifting and lowering the sealing cap 219. Below the manifold 209, a baffle 219s is provided as a furnace port cover body that can airtightly block the lower end opening of the manifold 209 in a state where the sealing cap 219 is lowered and the wafer cassette 217 is carried out from the processing chamber 201. The baffle 219s is made of a metal material such as SUS, for example, and is formed in a disc shape. On the upper surface of the baffle 219s, an O-ring 220c as a sealing component that abuts against the lower end of the manifold 209 is provided. The switching operation (lifting operation, rotating operation, etc.) of the baffle 219s is controlled by a baffle switching mechanism 115s.

[0042] In addition, the exhaust pipe 231, the manifold 209, the sealing cap 219, the rotating shaft 255, the baffle 219s, etc. are also made of an alloy with excellent heat resistance and corrosion resistance. As the alloy, in addition to SUS, Hastelloy (registered trademark) with improved heat resistance and corrosion resistance by adding iron (Fe), molybdenum (Mo), chromium (Cr), etc. to nickel (Ni), Inconel (registered trademark) with improved heat resistance and corrosion resistance by adding Fe, Cr, niobium (Nb), Mo, etc. to Ni, etc. can also be appropriately used.

[0043] The wafer cassette 217 as the substrate support device is configured to be able to support multiple wafers (for example, 25 to 200 wafers) in a horizontal posture and centered with each other in a vertically aligned and multi-stage manner, that is, arranged at intervals. The wafer cassette 217 is made of a heat-resistant material such as quartz or SiC, for example. At the lower part of the wafer cassette 217, a heat-insulating plate 218 made of a heat-resistant material such as quartz or SiC is supported in a horizontal posture in multiple stages.

[0044] A temperature sensor 263 as a temperature detector is provided in the reaction tube 203. Based on the temperature information detected by the temperature sensor 263, the energization condition of the heater 207 is adjusted so that the temperature in the processing chamber 201 reaches a desired temperature distribution. The temperature sensor 263 is provided along the inner wall of the reaction tube 203.

[0045] As Figure 3 shown, the controller 121 as the control unit (control device) is configured as a computer having a CPU (Central Processing Unit, central processor) 121a, a RAM (Random Access Memory, random storage) 121b, a storage device 121c, and an I / O interface 121d. The RAM 121b, the storage device 121c, and the I / O interface 121d are configured to be able to perform data exchange with the CPU 121a via an internal bus 121e. The controller 121 is connected to an input / output device 122 configured as a touch panel, for example.

[0046] The storage device 121c is composed of, for example, a flash memory, an HDD (Hard Disk Drive), etc. In the storage device 121c, a control program for controlling the operation of the substrate processing device, a process recipe that describes the steps, conditions, etc. of the substrate processing described later, a cleaning recipe that describes the steps, conditions, etc. of the cleaning processing described later, etc. are stored and can be read out. The process recipe is combined in such a way that the controller 121 executes each step in the substrate processing described later and obtains a predetermined result, and functions as a program. The cleaning recipe is combined in such a way that the controller 121 executes each step in the cleaning processing described later and obtains a predetermined result, and functions as a program. Hereinafter, the process recipe, the cleaning recipe, the control program, etc. are also simply collectively referred to as programs. In addition, the process recipe and the cleaning recipe are also simply referred to as recipes. When the term "program" is used in this specification, it includes the case of only a single recipe, the case of only a single control program, or the case of both. The RAM 121b is configured as a storage area (working area) for temporarily storing the programs, data, etc. read by the CPU 121a.

[0047] The I / O interface 121d is connected to the above-mentioned MFCs 241a to 241f, valves 243a to 243f, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotation mechanism 267, wafer cassette elevator 115, shutter switch mechanism 115s, etc.

[0048] The CPU 121a is configured to read out and execute the control program from the storage device 121c, and at the same time, in response to the input of an operation instruction from the input / output device 122, etc., read out the recipe from the storage device 121c. The CPU 121a is also configured to control the flow rate adjustment operations of various gases by the MFCs 241a to 241f, the opening and closing operations of the valves 243a to 243f, 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 operations of the wafer cassette 217 by the rotation mechanism 267, the lifting operation of the wafer cassette 217 by the wafer cassette elevator 115, the opening and closing operation of the shutter 219s by the shutter switch mechanism 115s, etc. according to the content of the read recipe.

[0049] The controller 121 can be configured by installing the above program stored in the external storage device 123 into a computer. The external storage device 123 includes, for example, magnetic disks such as HDDs, optical discs such as CDs, magneto-optical discs such as MOs, and semiconductor memories such as USB memories. The storage device 121c and the external storage device 123 are configured as computer-readable recording media. Hereinafter, these will be simply collectively referred to as recording media. In this specification, when using the term "recording medium", it includes the case of only the separate storage device 121c, the case of only the separate external storage device 123 alone, or the case including both of them. It should be noted that to provide a program to a computer, the external storage device 123 may not be used, and it can also be performed using the Internet or dedicated line communication methods.

[0050] (2) Substrate processing process

[0051] Regarding one process of the manufacturing process of a semiconductor device, an example of the substrate processing process of forming a film on a wafer 200 as a substrate using the above-described substrate processing apparatus, that is, an example of the film formation process will be described. In the following description, the operations of each part constituting the substrate processing apparatus are controlled by the controller 121.

[0052] During the film formation process of this embodiment, by taking the stage 1 of supplying HCDS gas as a raw material to the wafer 200 in the processing container and the stage 2 of supplying NH3 gas as a reactant to the wafer 200 in the processing container as one cycle, and performing this cycle a predetermined number of times, a silicon nitride film (SiN film) as a film containing Si and N is formed on the wafer 200.

[0053] In this specification, for convenience, the above-described film formation process is represented as follows. In the description of the following modification examples and the like, the same representation is also used.

[0054]

[0055] In this specification, when using the term "wafer", it includes the case meaning "the wafer itself" and the case meaning "a laminate of the wafer and a predetermined layer, film, etc. formed on its surface". In this specification, when using the term "wafer surface", it includes the case meaning "the surface of the wafer itself" and the case meaning "the surface of a predetermined layer, film, etc. formed on the wafer". In this specification, when it is described that "a predetermined layer is formed on the wafer", it includes the case of directly forming a predetermined layer on the surface of the wafer itself and the case of forming a predetermined layer on a layer or the like formed on the wafer. In this specification, the meaning of using the term "substrate" is the same as that of using the term "wafer".

[0056] (Wafer Loading and Cassette Loading)

[0057] After loading multiple wafers 200 into a cassette 217 (wafer loading), the shutter 219s is moved by the shutter switch mechanism 115s to open the lower end opening of the header 209 (open shutter). Then, as Figure 1 shown, the cassette 217 supporting multiple wafers 200 is lifted by the cassette elevator 115 and carried into the processing chamber 201 (cassette loading). In this state, the seal cap 219 is in a state where the lower end of the header 209 is sealed by the O-ring 220b.

[0058] (Pressure Adjustment and Temperature Adjustment)

[0059] Vacuum exhaust (pressure reduction exhaust) is performed by the vacuum pump 246 so that the inside of the processing chamber 201 (i.e., the space where the wafers 200 are present) reaches a desired pressure (vacuum degree). 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. In addition, heating is performed by the heater 207 so that the wafers 200 inside the processing chamber 201 reach a desired temperature. At this time, the energization of the heater 207 is feedback-controlled based on the temperature information detected by the temperature sensor 263 so that a desired temperature distribution is achieved inside the processing chamber 201. In addition, the wafer 200 is started to rotate by the rotation mechanism 267. At least during the period before the processing of the wafer 200 ends, the exhaust inside the processing chamber 201, the heating and rotation of the wafer 200 are continuously performed.

[0060] (Film Deposition Stage)

[0061] Then, the following Phase 1 and Phase 2 are sequentially implemented.

[0062] [Phase 1]

[0063] In this phase, HCDS gas is supplied to the wafers 200 inside the processing container (HCDS gas supply stage). Specifically, the valve 243a is opened, and HCDS gas flows into the gas supply pipe 232a. The flow rate of the HCDS gas is adjusted by the MFC241a, supplied into the processing chamber 201 via the nozzle 249a, and exhausted from the exhaust port 231a. At this time, HCDS gas is supplied to the wafers 200. At this time, the valves 243e and 243f can also be opened to supply N2 gas into the processing chamber 201 via the nozzles 249a and 249b.

[0064] As the processing conditions in this phase, for example:

[0065] HCDS gas supply flow rate: 0.01 - 2 slm, preferably 0.1 - 1 slm,

[0066] N2 gas supply flow rate (for each gas supply pipe): 0 - 10 slm,

[0067] Each gas supply time: 1 - 120 seconds, preferably 1 - 60 seconds,

[0068] Processing temperature: 250 - 800 °C, preferably 400 - 700 °C,

[0069] Processing pressure: 1 - 2666 Pa, preferably 67 - 1333 Pa.

[0070] It should be noted that the representation of the numerical range such as "250 - 800 °C" in this specification means that the lower limit value and the upper limit value are included in this range. For example, "250 - 800 °C" means "above 250 °C and below 800 °C". The same applies to other numerical ranges.

[0071] By supplying HCDS gas to the wafer 200 under the above conditions, a Cl-containing Si layer is formed on the outermost surface of the wafer 200 as the first layer. The Cl-containing Si layer is a substance formed by physical adsorption of HCDS, or partial decomposition of HCDS (hereinafter, represented as Si x Cl y ) through chemisorption, or deposition of Si due to thermal decomposition of HCDS, etc. The Cl-containing Si layer can be an adsorption layer (physical adsorption layer, chemisorption layer) of HCDS, Si x Cl y , or a Cl-containing Si layer (Si deposition layer). In this specification, the Cl-containing Si layer is also simply referred to as the Si layer.

[0072] After forming the first layer, close the valve 243a to stop supplying HCDS gas into the processing chamber 201. Then, evacuate the processing chamber 201 to remove the residual gas, etc. from the processing chamber 201 (purge stage). At this time, open the valves 243e, 243f to supply N2 gas into the processing chamber 201. The N2 gas acts as a purge gas.

[0073] As raw materials, in addition to HCDS gas, monochlorosilane (SiH3Cl, abbreviation: MCS) gas, dichlorosilane (SiH2Cl2, abbreviation: DCS) gas, trichlorosilane (SiHCl3, abbreviation: TCS) gas, tetrachlorosilane (SiCl4, abbreviation: STC) gas, octachlorotrisilane (Si3Cl8, abbreviation: OCTS) gas and other chlorosilane-based gases can also be used. These gases, like HCDS gas, are gases that can deposit films alone under the above processing conditions.

[0074] As an inert gas, in addition to N2 gas, inert gases such as Ar gas, He gas, Ne gas, and Xe gas can also be used. This also applies to the subsequent Stage 2 and the cleaning process.

[0075] [Stage 2]

[0076] After the end of Stage 1, NH3 gas is supplied to the wafer 200 in the processing container (i.e., the first layer formed on the wafer 200) (NH3 gas supply stage). Specifically, the valve 243b is opened, and NH3 gas flows into the gas supply pipe 232b. The flow rate of the NH3 gas is adjusted by the MFC241b, supplied into the processing chamber 201 via the nozzle 249b, and exhausted from the exhaust port 231a. At this time, NH3 gas is supplied to the wafer 200. At this time, the valves 243e and 243f can also be opened, and N2 gas is supplied into the processing chamber 201 via the nozzles 249a and 249b.

[0077] As the processing conditions in this stage, for example:

[0078] NH3 gas supply flow rate: 0.1 - 10 slm,

[0079] N2 gas supply flow rate (for each gas supply pipe): 0 - 2 slm,

[0080] NH3 gas supply time: 1 - 120 seconds, preferably 1 - 60 seconds,

[0081] Processing pressure: 1 - 4000 Pa, preferably 1 - 3000 Pa.

[0082] Other processing conditions are the same as those in Stage 1.

[0083] By supplying NH3 gas to the wafer 200 under the above conditions, at least a part of the first layer formed on the wafer 200 is nitrided (modified). By modifying the first layer, a second layer containing Si and N, that is, a SiN layer, is formed on the wafer 200. When forming the second layer, impurities such as Cl contained in the first layer will form a gaseous substance containing at least Cl during the modification reaction of the first layer by the NH3 gas and be discharged from the processing chamber 201. Thus, the second layer becomes a layer with fewer impurities such as Cl compared to the first layer.

[0084] After forming the second layer, the valve 243b is closed, and the supply of NH3 gas to the processing chamber 201 is stopped. Then, through the same processing steps as the purge stage in Stage 1, the gas remaining in the processing chamber 201 is removed from the processing chamber 201 (purge stage).

[0085] As the reaction body, in addition to NH3 gas, hydrogen nitride-based gases such as diazene (N2H2) gas, hydrazine (N2H4) gas, and N3H8 gas can also be used.

[0086] [Execute a predetermined number of times]

[0087] By performing Stage 1 and Stage 2 non-simultaneously, that is, by performing them out of phase as one cycle, and repeating this cycle a predetermined number of times (m times, where m is an integer of 1 or more), a SiN film with a predetermined composition and a predetermined film thickness can be formed on the wafer 200. The above cycle is preferably repeated multiple times. That is, it is preferable that the thickness of the second layer formed when performing one cycle is thinner than the desired film thickness, and the above cycle is repeated multiple times until the film thickness of the SiN film formed by stacking the second layer reaches the desired film thickness.

[0088] (Post-purge and atmospheric pressure restoration)

[0089] After the film formation stage, N2 gas as a purge gas is supplied into the processing chamber 201 from the nozzles 249a and 249b respectively, and exhausted from the exhaust port 231a. Thereby, the inside of the processing chamber 201 is purged, and the gas and reaction by-products remaining in the processing chamber 201 are removed from the processing chamber 201 (post-purge). Then, the atmosphere inside the processing chamber 201 is replaced with an inert gas (inert gas replacement), and the pressure inside the processing chamber 201 is restored to atmospheric pressure (atmospheric pressure restoration).

[0090] (Wafer cassette unloading and wafer release)

[0091] The wafer cassette elevator 115 lowers the sealing cap 219 to open the lower end of the header 209. Then, the processed wafer 200 is carried out from the lower end of the header 209 to the outside of the reaction tube 203 while being supported by the wafer cassette 217 (wafer cassette unloading). After the wafer cassette unloading, the baffle 219s is moved, and the lower end opening of the header 209 is sealed by the baffle 219s through the O-ring 220c (closing the baffle). After the processed wafer 200 is carried out to the outside of the reaction tube 203, it is taken out from the wafer cassette 217 (wafer release).

[0092] (3) Cleaning process

[0093] If the above substrate processing is performed, deposits including thin films such as SiN films will accumulate on the inner wall of the processing container, for example, the inner wall of the reaction tube 203, the surfaces of the nozzles 249a and 249b, the surface of the wafer cassette 217, etc. That is, deposits including the thin film will adhere to the surfaces of components in the processing chamber 201 heated to the film formation temperature and accumulate. Here, in the present embodiment, when the amount of deposits accumulated in the processing container, that is, the accumulated film thickness reaches a predetermined amount (thickness) before the deposits are peeled off and dropped, the inside of the processing container is cleaned.

[0094] In the cleaning process of the present embodiment, the following steps are performed:

[0095] Step A: Supplying a first gas containing a fluorine-based gas to the processing container at the first temperature after processing the wafer 200 as a substrate at a first flow rate and exhausting the gas to remove the above-mentioned deposits attached to the inside of the processing container.

[0096] Step B: Supplying a second gas that does not chemically react with fluorine at the second temperature to the processing container at the second temperature higher than the first temperature after Step A at a second flow rate higher than both the first flow rate and the third flow rate described later and exhausting the gas to physically remove and separate the residual fluorine in the processing container. And

[0097] Step C: Supplying a third gas that chemically reacts with fluorine at the third temperature to the processing container at the third temperature higher than the first temperature after Step A at a third flow rate and exhausting the gas to chemically remove and separate the residual fluorine in the processing container.

[0098] Hereinafter, an example of the cleaning process in which the first gas is F2 gas and NO gas (F2 gas + NO gas), the second gas is N2 gas, and the third gas is NO gas will be described using Figure 4 In the following description, the operations of each part constituting the substrate processing apparatus are controlled by the controller 121.

[0099] (Wafer Cassette Loading)

[0100] The shutter 219s is moved by the shutter switching mechanism 115s to open the lower end opening of the header 209 (open the shutter). Then, the empty wafer cassette 217, that is, the wafer cassette 217 not loaded with the wafer 200, is lifted by the wafer cassette elevator 115 and carried into the processing chamber 201. In this state, the seal cap 219 is in a state where the lower end of the header 209 is sealed by the O-ring 220b.

[0101] (Pressure Adjustment and Temperature Adjustment)

[0102] Vacuum exhaust (pressure reduction exhaust) is performed by a vacuum pump 246 so that a desired pressure (vacuum degree) is achieved inside the processing chamber 201. In addition, heating is performed by a heater 207 so that a desired first temperature is achieved inside the processing chamber 201. At this time, components inside the processing chamber 201, that is, the inner wall of the reaction tube 203, the surfaces of the nozzles 249a, 249b, the surface of the wafer cassette 217, etc. are also heated to the first temperature. In addition, the wafer cassette 217 is rotated by a rotation mechanism 267. The operation of the vacuum pump 246, the heating inside the processing chamber 201, and the rotation of the wafer cassette 217 are continuously performed until the subsequent stages A to C are completed. The wafer cassette 217 may not be rotated.

[0103] (Stage A: Supply of F2 gas + NO gas)

[0104] After the pressure and temperature inside the processing chamber 201 are stabilized, stage A is started. In this stage, F2 gas and NO gas are supplied to the processing container at the first temperature at the first flow rate and exhausted. Specifically, valves 243c and 243d are opened, and F2 gas flows into the gas supply pipe 232c and NO gas flows into the gas supply pipe 232d, respectively. The flow rates of the F2 gas and the NO gas are adjusted by MFCs 241c and 241d, respectively, and are supplied into the processing chamber 201 via the gas supply pipes 232a, 232b and the nozzles 249a, 249b. At this time, valves 243e and 243f may be opened simultaneously to supply N2 gas into the processing chamber 201 via the nozzles 249a, 249b.

[0105] As the processing conditions in stage A, the following are exemplified:

[0106] F2 gas supply flow rate (first flow rate): 0.5 to 10 slm,

[0107] NO gas supply flow rate (first flow rate): 0.5 to 10 slm,

[0108] N2 gas supply flow rate: 0.01 to 20 slm,

[0109] Each gas supply time: 1 to 60 minutes, preferably 10 to 20 minutes,

[0110] Processing temperature (first temperature): 100 to 500 °C, preferably 250 to 350 °C,

[0111] Processing pressure (first pressure): 1333 to 40000 Pa, preferably 1333 to 16665 Pa.

[0112] By supplying F2 gas and NO gas into the processing chamber 201 under the above processing conditions, NO gas can be added to the F2 gas, and these gases can be mixed and react in the processing chamber 201. Through such a reaction, active species such as fluorine radicals (F ＊ ), nitrosyl fluoride (FNO), etc. can be generated in the processing chamber 201 (hereinafter, these are also collectively referred to as FNO, etc.). As a result, in the processing chamber 201, there is a mixed gas formed by adding FNO, etc. to the F2 gas. The mixed gas formed by adding FNO, etc. to the F2 gas will contact the components in the processing chamber 201, for example, the inner wall of the reaction tube 203, the surfaces of the nozzles 249a, 249b, the surface of the wafer cassette 217, etc. At this time, through a thermal chemical reaction (etching reaction), the deposits adhering to the components in the processing chamber 201 can be removed. FNO, etc. play a role in assisting etching, that is, promoting the etching reaction by the F2 gas and increasing the etching rate of the deposits.

[0113] As the fluorine-based gas, in addition to F2 gas, hydrogen fluoride (HF) gas, nitrogen trifluoride (NF3) gas, chlorine trifluoride (ClF3), or a mixed gas of these can also be used. As the gas added to the fluorine-based gas, in addition to NO gas, hydrogen (H2) gas, oxygen (O2) gas, nitrous oxide (N2O) gas, isopropyl alcohol ((CH3)2CHOH, abbreviation: IPA) gas, methanol (CH3OH) gas, water vapor (H2O gas) can also be used.

[0114] (Purge and heating stage)

[0115] After a predetermined time, when the removal of the deposits from the processing container is completed, valves 243c and 243d are closed, and the supply of F2 gas and NO gas into the processing chamber 201 is stopped respectively. Then, through the same processing steps as the purge stage of stage 1, the gas remaining in the processing chamber 201, etc. is exhausted from the processing chamber 201 (purge stage).

[0116] However, even if the purging phase is carried out for a long time, it is difficult to completely remove fluorine from the processing container. This is because, at the end of phase A, fluorine is physically or chemically adsorbed on the surface of the components in the processing container. The residual fluorine adsorbed on the surface of the components in the processing container will not detach from the component surface even if the same purging phase and post-purging as in the above-mentioned phase 1 are carried out at the first temperature for a long time (e.g., 5 to 10 hours), and tends to continue to remain in the processing container. The fluorine remaining in the processing container becomes a factor that reduces the productivity of the subsequent substrate processing (batch processing) carried out after the cleaning process. Specifically, when the above-mentioned substrate processing is repeatedly carried out after the cleaning process, affected by the residual fluorine in the processing container, in at least the first few substrate processes, the film formation rate of the SiN film formed on the wafer 200 sometimes drops significantly.

[0117] In order to solve the above problems, in the present embodiment, after phase A is carried out, phase B and phase C described below are respectively carried out. By performing phase B, the residual fluorine in the processing container that is difficult to remove even if the above-mentioned purging phase is carried out for a long time can be physically detached from the surface of the components in the processing container, and thus removed from the processing container. In addition, by performing phase C, the residual fluorine in the processing container that is difficult to remove even if the above-mentioned purging phase is carried out for a long time can be chemically detached from the surface of the components in the processing container, and thus removed from the processing container. It should be noted that, as described later, in order to effectively remove the residual fluorine in the processing container, it is preferable to perform phase C after phase B. That is, it is preferable to perform phase B after phase A and perform phase C after phase B. That is, it is preferable to continuously perform them in the order of phase A, phase B, and phase C.

[0118] In phase B, in order to exert the above-mentioned function, it is necessary to raise the temperature in the processing container to a second temperature higher than the above-mentioned first temperature. In addition, in phase C, in order to exert the above-mentioned function, it is necessary to raise the temperature in the processing container to a third temperature higher than the above-mentioned first temperature. As described above, in the present embodiment, since phases A, B, and C are to be carried out in sequence, here, the output of the heater 207 is adjusted to first raise the temperature in the processing chamber 201 to the necessary temperature condition suitable for performing phase B, that is, a second temperature higher than the above-mentioned first temperature (heating-up phase). It should be noted that it is preferable to start phase B described below after the temperature in the processing chamber 201 reaches the second temperature and stabilizes. By waiting for the temperature in the processing chamber 201 to stabilize at the second temperature, the entire area in the processing container can be uniformly heated at the second temperature, and phase B described below can be carried out in this state. Therefore, the function of phase B described below, that is, the function of physically detaching and removing the residual fluorine in the processing container, can be obtained uniformly in the entire area of the processing container.

[0119] (Phase B: Large-flow N2 purging)

[0120] In this stage, N2 gas that does not chemically react with fluorine at the second temperature is supplied to the processing container at a second temperature higher than the first temperature at a second flow rate higher than both the above-mentioned first flow rate and the third flow rate described later, and exhausted. Specifically, valves 243e and 243f are opened, and N2 gas flows into gas supply pipes 232e and 232f respectively. The flow rate of the N2 gas is adjusted by MFCs 241e and 241f, and is supplied to the processing chamber 201 via gas supply pipes 232a and 232b and nozzles 249a and 249b (large-flow N2 purge). It should be noted that the second flow rate mentioned here refers to the total flow rate of the N2 gas supplied to the processing container, that is, the total flow rate of the N2 gas supplied via nozzles 249a and 249b.

[0121] Examples of the processing conditions in stage B are as follows:

[0122] N2 gas supply flow rate (second flow rate): 5 - 50 slm,

[0123] N2 gas supply time: 1 - 300 minutes, preferably 30 - 120 minutes,

[0124] Processing temperature (second temperature): 500 - 800 °C,

[0125] Processing pressure (second pressure): 13 - 1333 Pa.

[0126] By supplying N2 gas to the processing container at a second temperature higher than the first temperature and at a second flow rate higher than each of the first flow rate and the third flow rate, it is possible to impact the residual fluorine with the N2 gas supplied in a large flow rate in a state where high thermal energy is imparted to the residual fluorine in the processing container. That is, it is possible to impact the residual fluorine with decreased adsorption force due to the imparted high thermal energy by N2 gas molecules at a high flow rate and with a high probability. Thus, it is possible to physically separate and remove the residual fluorine from the processing container efficiently and effectively. The separated residual fluorine is discharged from the exhaust port 231a.

[0127] By performing this stage, most or all of the residual fluorine physically adsorbed on the surface of the components in the processing container can be physically separated and removed from the processing container. In addition, in this stage, not only can the residual fluorine physically adsorbed on the surface of the components in the processing container be physically separated and removed, but also a part of the residual fluorine chemically adsorbed on the surface of the components can be physically separated and removed. However, even if this stage is implemented for a long time, it is difficult to completely separate all the residual fluorine chemically adsorbed on the surface of the components in the processing container. Here, after the predetermined time of implementing this stage, the subsequent stage C is implemented.

[0128] As the second gas, in addition to N2 gas, inert gases such as He gas, Ar gas, Ne gas, and Xe gas can also be used.

[0129] (Stage C: NO purge)

[0130] In this stage, NO gas that undergoes a chemical reaction with fluorine at the third temperature is supplied to the processing container at the third temperature, which is higher than the first temperature, and exhausted. Specifically, valve 243d is opened, and NO gas flows into gas supply pipe 232d. The flow rate of the NO gas is adjusted by MFC241d and supplied to processing chamber 201 via gas supply pipe 232b and nozzle 249b (NO purge).

[0131] As the processing conditions in stage C, the following are exemplified:

[0132] NO gas supply flow rate (third flow rate): 0.01 - 10 slm,

[0133] NO gas supply time: 1 - 120 minutes, preferably 30 - 60 minutes,

[0134] Processing temperature (third temperature): 500 - 750 °C,

[0135] Processing pressure (third pressure): 13 - 2000 Pa.

[0136] By supplying NO gas at the third temperature, which is higher than the first temperature, NO gas can be supplied to the residual fluorine chemisorbed in the processing container, and a chemical reaction occurs with it. As a result, the residual fluorine in the processing container can be promoted to chemically desorb. The desorbed residual fluorine is discharged from exhaust port 231a.

[0137] By performing this stage, most or all of the residual fluorine chemisorbed on the surface of the components in the processing container can be removed from the processing container. In this way, in stage C, the residual fluorine that was not completely removed in stage B can be chemically desorbed and removed. It should be noted that in this stage, not only can the residual fluorine chemisorbed on the surface of the components in the processing container be desorbed, but also a part of the residual fluorine physically adsorbed on the surface of the components can be chemically desorbed and removed. However, in order to remove the residual fluorine physically adsorbed on the surface of the components in the processing container, considering the removal efficiency and gas cost, stage B is more advantageous than stage C. Therefore, it is preferable to perform stage B before stage C as in this embodiment, and in stage C, the residual fluorine that was not removed in stage B is removed.

[0138] As described above, by sequentially performing stage B for physically desorbing and removing the residual fluorine and stage C for chemically desorbing and removing the residual fluorine, the residual fluorine in the processing container can be efficiently and low - costly discharged from the processing container.

[0139] It should be noted that the processing pressure (the third pressure) in this stage is preferably set to a pressure greater than the above-mentioned second pressure (the third pressure > the second pressure). By setting the processing pressure in this stage in this way, the reactivity of the residual fluorine and NO gas in the processing container can be improved, and their reaction can be promoted. As a result, the chemical detachment of the residual fluorine from the processing container can be further promoted, and the residual fluorine in the processing container can be removed efficiently and effectively. In addition, by setting the processing pressure (the third pressure) in this stage to a large pressure as described above, the residence time of the NO gas in the processing container can be extended, and the NO gas can reach every corner of the processing container. Thus, the residual fluorine can be removed uniformly from all areas in the processing container. That is, the function of the above-mentioned stage C, that is, the function of chemically detaching and removing the residual fluorine in the processing container, can be obtained uniformly in all areas in the processing container.

[0140] In addition, the processing temperature (the third temperature) in this stage is preferably the same as the processing temperature (the second temperature) in stage B (the third temperature = the second temperature). Further, the third temperature can also be the same as the film-forming temperature (the processing temperature when processing the wafer 200) (the third temperature = the second temperature = the film-forming temperature). By setting the processing temperature in this stage in this way, there is no need to set a stage for changing the temperature in the processing container, the time required for raising and lowering the temperature in the processing container can be saved, and the processing time can be shortened accordingly. Thus, the downtime of the substrate processing apparatus can be shortened. It should be noted that the third temperature can also be greater than the second temperature (the third temperature > the second temperature). In this case, in stage C, the reaction between the residual fluorine and NO gas in the processing container can be further promoted, and the function of chemically detaching and removing the residual fluorine can be further enhanced. In addition, the second temperature can also be greater than the third temperature (the second temperature > the third temperature). In this case, in stage B, a state where the residual fluorine in the processing container is more easily detached can be achieved, and the function of physically detaching and removing the residual fluorine can be further enhanced.

[0141] As the third gas, in addition to NO gas, nitrous oxide (N2O) gas, nitrogen dioxide (NO2) gas and other nitrogen oxide gases can also be used. It should be noted that when using H2 gas or NH3 gas as the third gas, the residual fluorine can also react with the third gas to remove the residual gas from the processing container. However, when using these gases as the third gas, HF and the like will be generated when the residual fluorine in the processing container reacts with the third gas, and sometimes the components (especially quartz components) in the processing container will be etched and damaged by the generated HF and the like. As in this embodiment, by using a hydrogen-free nitrogen oxide-based gas as the third gas, the above problems can be eliminated.

[0142] (Post-purge and atmospheric pressure restoration)

[0143] After the end of phases A to C, the inside of the processing chamber 201 is purged (post-purge) by the same processing steps as the post-purge in the above-described substrate processing process. Then, the atmosphere inside the processing chamber 201 is replaced with an inert gas (inert gas replacement), and the pressure inside the processing chamber 201 is restored to atmospheric pressure (atmospheric pressure restoration).

[0144] (Wafer cassette unloading)

[0145] The wafer cassette elevator 115 lowers the sealing cap 219 and opens the lower end of the manifold 209. Then, the empty wafer cassette 217 is carried out from the lower end of the manifold 209 to the outside of the reaction tube 203 (wafer cassette unloading). After this series of processes is completed, the above-described substrate processing process is started again.

[0146] (Pre-coating)

[0147] It should be noted that before starting the above-described substrate processing process again, it is preferable to process the wafer 200 in the processing container at the fourth temperature after phase C, that is, to perform the same processing as the film formation phase of the above-described substrate processing process, and form a pre-coating (SiN layer) containing Si and N on the surface of the components in the processing container (pre-coating). This processing is preferably performed in a state where the empty wafer cassette 217 is accommodated in the processing container after the cleaning process is performed.

[0148] The fourth temperature can be set to the same temperature as the second temperature and the third temperature. For example, the fourth temperature can be set to the same temperature as the second temperature and the third temperature (fourth temperature = third temperature = second temperature). In addition, the fourth temperature can further be set to the same temperature as the film formation temperature (the processing temperature when processing the wafer 200) (fourth temperature = third temperature = second temperature = film formation temperature). By setting the fourth temperature in this way, there is no need to provide a phase for changing the temperature inside the processing container, the time required for raising and lowering the temperature inside the processing container can be saved, and the processing time can be shortened to a corresponding extent. As a result, the downtime of the substrate processing apparatus can be shortened. It should be noted that the pre-coating is preferably performed during the period after phase C and before the above-described wafer cassette unloading.

[0149] (4) Effects of this embodiment

[0150] According to this embodiment, one or more of the following effects are obtained.

[0151] (a) After phase A is performed, phase B is performed, that is, N2 gas is supplied and exhausted at a second flow rate higher than both the first flow rate and the third flow rate into the processing container at the second temperature higher than the first temperature, so that the residual fluorine inside the processing container can be physically removed and eliminated.

[0152] In addition, after performing Stage A, Stage C is performed, that is, NO gas is supplied to the processing container at a third temperature higher than the first temperature and exhausted, so that the residual fluorine in the processing container can be chemically removed and eliminated.

[0153] By the actions of these Stages B and C, the residual fluorine that is difficult to remove from the processing container even when the same stages as the purge stage and post-purge of the above-mentioned Stage 1 are performed for a long time can be removed from the processing container. By removing the residual fluorine from the processing container and then performing the cleaning process, the substrate processing can be restarted without reducing the productivity of the substrate processing. Thus, the downtime of the substrate processing apparatus can be shortened.

[0154] (b) By starting Stage B after the temperature in the processing chamber 201 reaches the second temperature and stabilizes, the action of Stage B, that is, the action of physically removing the residual fluorine in the processing container, can be uniformly obtained in all regions of the processing container. It should be noted that if Stage B is started before the temperature in the processing chamber 201 reaches the second temperature and stabilizes, sometimes the action of Stage B, that is, the action of physically removing the residual fluorine in the processing container, cannot be uniformly obtained due to the temperature difference in the processing container.

[0155] (c) By making the pressure (third pressure) in the processing container in Stage C greater than the pressure (second pressure) in the processing container in Stage B (third pressure > second pressure), compared with the case where the third pressure ≤ second pressure is set, the chemical removal of the residual fluorine in the processing container can be promoted in Stage C. As a result, the above-mentioned downtime can be shortened.

[0156] (d) By performing Stage C after performing Stage B, the residual fluorine can be efficiently removed from the processing container. Thus, the above-mentioned downtime can be further shortened. In addition, an increase in gas cost when removing the residual fluorine from the processing container can be suppressed.

[0157] (e) By setting the processing temperature (third temperature) in Stage C to the same temperature as the processing temperature (second temperature) in Stage B (third temperature = second temperature), there is no need to provide a stage for changing the temperature in the processing container, the time required for raising and lowering the temperature in the processing container can be saved, and the processing temperature can be shortened to a certain extent. Thus, the above-mentioned downtime can be further shortened.

[0158] (f) By setting the processing temperature (third temperature) in stage C to a temperature higher than the processing temperature (second temperature) in stage B (third temperature > second temperature), chemical detachment of residual fluorine in the processing container can be promoted in stage C as compared with the case where the third temperature ≤ second temperature is set. Further, by setting the processing temperature (second temperature) in stage B to a temperature higher than the processing temperature (third temperature) in stage C (second temperature > third temperature), physical detachment of residual fluorine in the processing container can be promoted in stage B as compared with the case where the second temperature ≤ third temperature is set.

[0159] (g) By performing pre - coating after stage C and before the substrate processing step, the film - forming rate and the quality of substrate processing can be stabilized when the subsequent film - forming process is carried out.

[0160] (h) By carrying out stages A, B, and C in a non - plasma atmosphere, that is, by applying heat energy without applying plasma energy in the atmosphere inside the processing container to carry out these stages, damage to the components inside the processing container caused by plasma can be avoided.

[0161] (i) Even when using a first gas other than F2 gas + NO gas in stage A, a second gas other than N2 gas in stage B, and a third gas other than NO gas in stage C, the same effects as the above - mentioned effects can be obtained.

[0162] (5) Variation

[0163] The cleaning process is not limited to the above - described embodiments and can be changed to the following variations. These variations can be combined arbitrarily. Unless otherwise specified, the processing steps and processing conditions in each stage of each variation can be the same as those in each stage shown in the above - described embodiments.

[0164] (Variation 1)

[0165] In stage B, the following stages can also be repeatedly alternated multiple times: the stage of supplying N2 gas into the processing container and the stage of evacuating (vacuum - evacuating, pumping) the inside of the processing container in a state where the supply of N2 gas into the processing container is stopped. That is, in stage B, a large flow rate of N2 gas can also be intermittently supplied into the processing container to perform cyclic purging of the inside of the processing container.

[0166] As the processing conditions in stage B at this time, the following are exemplified:

[0167] N2 gas supply time: 10 - 300 seconds / cycle, preferably 60 - 120 seconds / cycle,

[0168] Vacuum exhaust time: 10 to 300 seconds / cycle, preferably 60 to 120 seconds / cycle,

[0169] Number of cycles: 1 to 300 times, preferably 30 to 120 times,

[0170] Minimum pressure: 13 to 30 Pa,

[0171] Maximum pressure: 30 to 1333 Pa.

[0172] Other processing conditions can be the same as those in Stage B of the above-described embodiment.

[0173] In this modification example, the same effects as those of the above-described cleaning process can also be obtained by using Figure 4 As described above. In addition, according to this modification example, in Stage B, the physical detachment of the residual fluorine in the processing container can be further promoted, and the residual fluorine can be more effectively removed from the processing container. As a result, the above-described downtime can be further shortened.

[0174] (Modification Example 2)

[0175] Stages B and C can also be repeatedly alternated multiple times. In this modification example, the same effects as those of the above-described cleaning process can be obtained by using Figure 4 As described above. In addition, according to this modification example, the residual fluorine in the processing container can be removed more effectively, and as a result, the above-described downtime can be further shortened.

[0176] (Modification Example 3)

[0177] Stages B and C can also be repeatedly alternated multiple times while changing the ratio of the implementation time of Stage C to the implementation time of Stage B when repeatedly alternating these stages. For example, when repeatedly alternating Stages B and C multiple times, the implementation time T C of Stage C can be gradually increased relative to the implementation time T B of Stage B (T C / T B ). That is, when repeatedly alternating Stages B and C multiple times, the ratio of chemically detaching and removing the residual fluorine can be gradually increased.

[0178] In this modification example, the same effects as those of the above-described cleaning process can also be obtained by using Figure 4 As described above. In addition, according to this modification example, the residual fluorine that was not completely removed in Stage B can be removed more efficiently and effectively. As a result, the above-described downtime can be further shortened. In addition, the amount of N2 gas that is exhausted from the exhaust pipe 231 without contributing to the detachment of the residual fluorine in the processing container can be appropriately reduced, and the gas cost can be reduced.

[0179] (Modification Example 4)

[0180] Stage B can also be carried out after stage C. That is, stages A, C, and B can be carried out continuously in sequence. The same effect as that of the above-described cleaning process can also be obtained in this modification. However, as described above, if stages A, B, and C are carried out in sequence, the efficiency of removing residual fluorine from the processing container is high, and in addition, an increase in gas cost can be suppressed, which is therefore advantageous. Figure 4 The same effect as that of the above-described cleaning process can also be obtained in this modification. However, as described above, if stages A, B, and C are carried out in sequence, the efficiency of removing residual fluorine from the processing container is high, and in addition, an increase in gas cost can be suppressed, which is therefore advantageous.

[0181] <Other Embodiments>

[0182] 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 the gist thereof.

[0183] In the above-described embodiments, an example of cleaning the inside of the processing container after forming a SiN film on the wafer in the processing container has been described. However, the present invention is not limited to such an embodiment. For example, the above-described cleaning process is also suitably applicable to the case of cleaning the inside of the processing container after forming a silicon film (Si film), a silicon oxide film (SiO film), a silicon oxynitride carbon film (SiOCN film), a silicon oxycarbon film (SiOC film), a silicon oxynitride film (SiON film), a silicon carbonitride film (SiCN film), a silicon boron carbonitride film (SiBCN film), a silicon boron nitride film (SiBN film), etc. on the wafer in the processing container. In addition, as the film formation method, it is not limited to the method of alternately supplying a raw material and a reactant to the wafer 200, and it may also be a method of simultaneously and continuously supplying a raw material and a reactant to the wafer 200, a method of simultaneously and intermittently supplying a raw material and a reactant. In addition, a method of continuously supplying one of the raw material and the reactant while intermittently supplying the other may also be employed. In these cases, the same effect as that of the above-described embodiments can be obtained.

[0184] The formulations used in the substrate processing and the cleaning processing are preferably prepared respectively corresponding to the processing contents and stored in the storage device 121c via a telecommunication line and an external storage device 123. Moreover, preferably, when starting the substrate processing and the cleaning processing, the CPU 121a appropriately selects an appropriate formulation from among a plurality of formulations stored in the storage device 121c corresponding to the contents of the substrate processing and the cleaning processing. Thereby, it is possible to reproducibly form films of various film species, composition ratios, film qualities, and film thicknesses with a single substrate processing apparatus. In addition, appropriate cleaning processing can be performed corresponding to the deposits containing various films adhering to the inside of the processing container (processing chamber 201). In addition, the burden on the operator can be reduced, operation errors can be avoided, and the processing can be started quickly.

[0185] The above-described recipe is not limited to a newly established recipe. For example, it can also be prepared by modifying an existing recipe already installed in the substrate processing apparatus. When modifying the recipe, the modified recipe can also be installed in the substrate processing apparatus via a telecommunication line or a recording medium on which the recipe is recorded. In addition, the input / output device 122 provided in the existing substrate processing apparatus can also be operated to directly modify the existing recipe installed in the substrate processing apparatus.

[0186] In the above-described embodiment, an example of forming a film and cleaning the inside of the processing container using a batch-type substrate processing apparatus that processes multiple substrates at once has been described. The present invention is not limited to the above-described embodiment. For example, it is also suitable for use in the case of forming a film and cleaning the inside of the processing container using a single-wafer type substrate processing apparatus that processes one or a few substrates at once. In addition, in the above-described embodiment, an example of forming a film and cleaning the inside of the processing container using a substrate processing apparatus having a hot-wall type processing furnace has been described. However, the present invention is not limited to the above-described embodiment, and it is also suitable for use in the case of forming a film and cleaning the inside of the processing container using a substrate processing apparatus having a cold-wall type processing furnace.

[0187] Even when using these substrate processing apparatuses, substrate processing and cleaning processing can still be performed in the same processes and processing conditions as in the above-described embodiment and modified example, and the same effects as in the above-described embodiment and modified example can be obtained.

[0188] In addition, the above-described embodiment and modified example can be used in appropriate combination. The processing steps and processing conditions at this time can be the same as, for example, the processing steps and processing conditions of the above-described embodiment.

[0189] Examples

[0190] Hereinafter, Figure 5 and Figure 6 will be used to describe examples and comparative examples.

[0191] Using Figure 1 the substrate processing apparatus shown, substrate processing for forming a SiN film on a wafer is performed, that is, batch processing (BAT) for simultaneously forming a SiN film on multiple wafers is performed a predetermined number of times. After that, as a comparative example, a stage of removing deposits in the processing container using F2 gas + NO gas (F2 + NO_CLN) and a stage of performing post-purge on the inside of the processing container (After_PRG) (cleaning X) are sequentially implemented. Then, after pre-coating (Pre_CT) inside the processing container, BAT is repeatedly performed. The implementation times of After_PRG, Pre_CT, and each BAT are 2 hours, 2 hours, and 4 hours, respectively. Other processing conditions are the same as those in each stage of the examples described later.

[0192] After cleaning X, the above BAT is repeatedly performed. Then, as an example, the following steps are sequentially performed: the step of removing deposits in the processing container using F2 gas + NO gas (F2+NO_CLN), the temperature increase step (Ramp_Up), the step of physically removing residual fluorine by circulating and purging the inside of the processing container with a large flow rate of N2 gas (N2_cycle_PRG), the step of chemically removing residual fluorine by purging the inside of the processing container with NO gas (NO_PRG), and the step of performing post-purging on the inside of the processing container (After_PRG) (cleaning Y). Then, after pre-coating (Pre_CT) inside the processing container, BAT is repeatedly performed. The implementation times of Ramp_Up, N2_cycle_PRG, and NO_PRG are 0.5 hours, 1 hour, and 0.5 hours, respectively. The implementation times of After_PRG, Pre_CT, and each BAT are the same as those in the comparative example, which are 2 hours, 2 hours, and 4 hours, respectively. Other processing conditions are set to predetermined conditions within the processing conditions described in the above embodiment.

[0193] After performing cleanings X and Y, each time the above BAT is performed, the in-plane average film thickness of the SiN film formed on the wafer (hereinafter referred to as the in-plane average film thickness) is measured. Figure 5 shows the measurement results of the in-plane average film thickness of the SiN film. Figure 5 The horizontal axis of shows the number of substrate processes after performing cleanings X and Y, that is, the number of batch processes (number of BATs), Figure 5 The vertical axis of shows the in-plane average film thickness of the SiN film formed on the wafer The white hollow bars in the figure show the in-plane average film thickness of the SiN film formed on the wafers arranged in the upper part (Top) of the wafer arrangement area, and the grid bars show the in-plane average film thickness of the SiN film formed on the wafers arranged in the lower part (Btm) of the wafer arrangement area.

[0194] As Figure 5 shown, compared with the BATs after cleaning X (the 1st to 3rd times) and the subsequent BATs (after the 4th time), the in-plane average film thickness of the SiN film formed on the wafer becomes thinner, and in the BATs after the cleaning process, the film formation rate temporarily decreases. In contrast, in the BATs after cleaning Y, there is no difference in the in-plane average film thickness of the SiN film formed on the wafer between the initial BAT (the 1st time) and the subsequent BATs (the 2nd time and after), and there is no temporary decrease in the film formation rate in the BATs after the cleaning process.

[0195] As Figure 6 shown, in the comparative example, from F2+NO _After CLN, until it becomes possible to start substrate processing on the product wafers, that is, until it becomes possible to start batch processing (product BAT) for simultaneously forming SiN films on multiple product wafers, it is necessary to perform 3 test BATs with a low and unstable film formation rate, resulting in a downtime of about 16 hours. In contrast, in the embodiment, from F2 + NO _ After CLN, the first BAT performed can be a product BAT with a high and stable film formation rate (no test BAT is required). As a result, the downtime can be suppressed to about 6 hours. In this way, in the embodiment, after cleaning the inside of the processing container, the subsequent substrate processing can be performed without reducing the productivity, and the downtime of the substrate processing apparatus can be significantly shortened.

Claims

1. A cleaning method, which is a cleaning method for a processing container, comprises the following steps: (a) A step of supplying a first gas containing a fluorine-based gas and a nitrogen oxide-based gas to the processing container at a first temperature after processing the substrate at a first flow rate and exhausting the gas to remove substances attached to the inside of the processing container; (b) A step of supplying a second gas containing an inert gas that does not chemically react with fluorine at a second temperature higher than the first temperature to the processing container at a second flow rate higher than both the first flow rate and a third flow rate after performing (a) and exhausting the gas to physically separate and remove residual fluorine in the processing container; (c) A step of supplying a third gas containing a nitrogen oxide-based gas that chemically reacts with fluorine at a third temperature higher than the first temperature to the processing container at the third flow rate after performing (a) and exhausting the gas to chemically separate and remove residual fluorine in the processing container, and A step of making the pressure in the processing container in (c) greater than the pressure in the processing container in (b); (b) starts after the temperature in the processing container reaches the second temperature and stabilizes.

2. The cleaning method according to claim 1, wherein (c) is performed after (b).

3. The cleaning method according to claim 2, wherein, (c) is performed after the temperature in the processing container stabilizes at the third temperature.

4. The cleaning method according to claim 1, wherein In (c), residual fluorine not completely removed in (b) is separated and removed.

5. The cleaning method according to claim 1, wherein, The second temperature and the third temperature are the same temperature.

6. The cleaning method according to claim 1, wherein, It further has (d) a step of performing the same processing as the processing of the substrate on the processing container at a fourth temperature after performing (c), and making the second temperature, the third temperature, and the fourth temperature the same temperature.

7. The cleaning method according to claim 1, wherein, In (b), the steps of supplying the second gas to the processing container and exhausting the gas from the processing container are repeatedly alternated multiple times.

8. The cleaning method according to claim 1, wherein, The nitrogen oxide-based gas contains nitrogen monoxide gas.

9. The cleaning method according to claim 1, wherein, (b) and (c) are repeatedly alternated multiple times.

10. The cleaning method according to claim 9, wherein, When (b) and (c) are repeatedly alternated multiple times, the ratio of the implementation time of (c) to the implementation time of (b) is changed.

11. The cleaning method according to claim 1, wherein, (a), (b), and (c) are performed in a non-plasma atmosphere.

12. The cleaning method according to claim 1, wherein, (a), (b), and (c) are performed by applying heat energy without applying plasma energy to the atmosphere in the processing container.

13. A method for manufacturing a semiconductor device, which has a step of processing a substrate in a processing container and a step of cleaning the inside of the processing container, The step of cleaning the inside of the processing container comprises: (a) A step of supplying a first gas containing a fluorine-based gas and a nitrogen oxide-based gas to the processing container at a first temperature after processing the substrate at a first flow rate and exhausting the gas to remove substances attached to the inside of the processing container; (b) A step of supplying a second gas containing an inert gas that does not chemically react with fluorine at the second temperature into the processing container at a second temperature higher than the first temperature after (a), exhausting the gas, and physically separating and removing the residual fluorine in the processing container. (c) A step of supplying a third gas containing a nitrogen oxide-based gas that chemically reacts with fluorine at the third temperature into the processing container at a third temperature higher than the first temperature after (a), exhausting the gas, and chemically separating and removing the residual fluorine in the processing container, and A step of making the pressure in the processing container in (c) greater than the pressure in the processing container in (b). The step (b) starts after the temperature in the processing container reaches the second temperature and stabilizes.

14. A substrate processing apparatus having: A processing container for processing a substrate. A heater for heating the inside of the processing container. A first gas supply system for supplying a first gas into the processing container. A second gas supply system for supplying a second gas into the processing container. A third gas supply system for supplying a third gas into the processing container. An exhaust system for exhausting gas from the processing container, and A control unit configured to be able to control the heater, the first gas supply system, the second gas supply system, the third gas supply system, and the exhaust system so as to clean the inside of the processing container by performing the following processing: (a) A process of supplying the first gas containing a fluorine-based gas and a nitrogen oxide-based gas into the processing container at the first temperature after processing the substrate at a first flow rate and exhausting the gas to remove substances adhering to the inside of the processing container. (b) A process of supplying the second gas containing an inert gas that does not chemically react with fluorine at the second temperature into the processing container at a second temperature higher than the first temperature after (a), exhausting the gas at a second flow rate higher than both the first flow rate and the third flow rate, and physically separating and removing the residual fluorine in the processing container. (c) A process of supplying the third gas containing a nitrogen oxide-based gas that chemically reacts with fluorine at the third temperature into the processing container at a third temperature higher than the first temperature after (a), exhausting the gas at the third flow rate, and chemically separating and removing the residual fluorine in the processing container, and A process of making the pressure in the processing container in (c) greater than the pressure in the processing container in (b). The step (b) starts after the temperature in the processing container reaches the second temperature and stabilizes.

15. A computer-readable program product recording a program for causing a computer to execute steps for cleaning the inside of a processing container by performing the following steps: (a) A step of supplying a first gas containing a fluorine-based gas and a nitrogen oxide-based gas at a first flow rate into a processing container of the substrate processing apparatus at a first temperature after processing the substrate, and exhausting the gas to remove substances adhering to the inside of the processing container. (b) A step of supplying a second gas containing an inert gas that does not chemically react with fluorine at a second temperature, which is higher than the first temperature, into the processing container after step (a) at a second flow rate that is higher than both the first flow rate and a third flow rate, and exhausting the gas to physically separate and remove residual fluorine in the processing container. (c) A step of supplying a third gas containing a nitrogen oxide-based gas that chemically reacts with fluorine at a third temperature, which is higher than the first temperature, into the processing container after step (a) at the third flow rate, and exhausting the gas to chemically separate and remove residual fluorine in the processing container, and A step of making the pressure in the processing container in (c) greater than the pressure in the processing container in (b). Step (b) starts after the temperature in the processing container reaches the second temperature and stabilizes.

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