Substrate processing method, semiconductor device manufacturing method, substrate processing apparatus, and recording medium

Abstract

The present application has a process of forming a film on a substrate by performing a cycle of (a) a process of supplying a raw material gas to the substrate provided with a recess on a surface, and (b) a process of supplying a reaction gas to the substrate, a prescribed number of times, in (a), the raw material gas is supplied to the substrate in multiple times, and the processing conditions at the time of initially supplying the raw material gas are set to processing conditions capable of suppressing self-decomposition of the raw material gas as compared to the processing conditions at the time of supplying the raw material gas from the second time onward.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a substrate processing method, a manufacturing method of a semiconductor device, a substrate processing apparatus, and a recording medium. BACKGROUND

[0002] As one of the processes of manufacturing a semiconductor device, there is a substrate processing process of supplying a raw material gas and a reaction gas to a substrate to form a film thereon (see, for example, Patent Literature 1).

[0003] PRIOR ART DOCUMENT

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2014-208883 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] An object of the present disclosure is to improve step coverage without reducing a film formation rate of a film formed on a substrate.

[0008] MEANS FOR SOLVING THE PROBLEMS

[0009] According to one embodiment of the present disclosure, there is provided a technology of forming a film on a substrate by executing a cycle of (a) a process of supplying a raw material gas to a substrate provided with a recess on a surface and (b) a process of supplying a reaction gas to the substrate a predetermined number of times,

[0010] In (a), the raw material gas is supplied to the substrate in multiple times, and a processing condition at the time of initially supplying the raw material gas is set to a processing condition capable of suppressing self-decomposition of the raw material gas as compared with a processing condition at the time of supplying the raw material gas for the second time or later.

[0011] EFFECT OF THE INVENTION

[0012] According to the present disclosure, a technology capable of improving step coverage without reducing a film formation rate of a film formed on a substrate can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0013] [ Figure 1 ] Figure 1 is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus suitable for use in one embodiment of the present disclosure, and is a diagram showing a processing furnace 202 portion in a longitudinal cross-sectional view.

[0014] [ Figure 2 ] Figure 2 ​This is a schematic diagram of a vertical processing furnace suitable for use in one embodiment of the present disclosure, and is based on... Figure 1 The AA-line sectional view shows part of the processing furnace 202.

[0015] [ Figure 3 ] Figure 3 This is a schematic configuration diagram of the controller 121 of a substrate processing apparatus suitable for use in one embodiment of this disclosure, and a block diagram showing the control system of the controller 121.

[0016] [ Figure 4 ] Figure 4 The flowchart illustrates the film-forming sequence in one embodiment of this disclosure, and is a diagram showing the timing of the supply of feed gas, reactant gas, and inactive gas, and the shift in the partial pressure of the feed gas.

[0017] [ Figure 5 ] Figure 5 (a) is a partially enlarged cross-sectional view of the surface of wafer 200 after the initial layer is formed in the recess during the initial stage of step A of the film formation sequence in one embodiment of this disclosure. Figure 5 (b) is a partially enlarged cross-sectional view of the surface of wafer 200 after the first layer is formed in the recess in step A of the film formation sequence in one embodiment of this disclosure. Detailed Implementation

[0018] <One way of publishing this text>

[0019] The following is mainly based on Figures 1-4 This disclosure will be described in one manner. It should be noted that the accompanying drawings used in the following description are schematic, and the dimensional relationships and ratios of the elements in the drawings do not necessarily correspond to the actual dimensions. Furthermore, the dimensional relationships and ratios of elements in multiple drawings are not necessarily consistent with each other.

[0020] (1) Composition of substrate processing device

[0021] like Figure 1 As shown, the processing furnace 202 has a heater 207 that functions as a temperature regulator (heating unit). The heater 207 is cylindrical and is vertically mounted by being supported on a retaining plate. The heater 207 also functions as an activation mechanism (excitation unit) that uses heat to activate (excite) the gas.

[0022] On the inner side of the heater 207, a reaction tube 203 is arranged concentrically with 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 an upper end closed and a lower end open. Below the reaction tube 203, a manifold 209 is arranged concentrically with the reaction tube 203. The manifold 209 is made of a metal material such as stainless steel (SUS), and has a cylindrical shape with upper and lower ends open. The upper end of the manifold 209 is engaged with the lower end of the reaction tube 203, and supports 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 like 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 accommodate a wafer 200 as a substrate. Processing of the wafer 200 is performed in the processing chamber 201.

[0023] In the processing chamber 201, nozzles 249a to 249c as first to third supply portions are provided so as to penetrate the side wall of the manifold 209, respectively. 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. On the nozzles 249a to 249c, gas supply pipes 232a to 232c are connected, respectively. The nozzles 249a to 249c are different nozzles from each other, and the nozzles 249b and 249c are each disposed adjacent to the nozzle 249a.

[0024] On the gas supply pipes 232a to 232c, mass flow controllers (MFCs) 241a to 241c as flow controllers (flow control portions) and valves 243a to 243c as on-off valves are provided in this order from the upstream side of the gas flow, respectively. On the gas supply pipe 232a on the downstream side from the valve 243a, a gas supply pipe 232d is connected. On the gas supply pipe 232b on the downstream side from the valve 243b, a gas supply pipe 232e is connected. On the gas supply pipes 232d and 232e, MFCs 241d and 241e and valves 243d and 243e are provided in this order from the upstream side of the gas flow, respectively. The gas supply pipes 232a to 232e are made of a metal material such as SUS.

[0025] As Figure 2As shown, the nozzles 249a to 249c are respectively provided in a space in the form of a circular ring in plan view between the inner wall of the reaction tube 203 and the wafer 200, rising from the lower portion of the inner wall of the reaction tube 203 to the upper portion thereof in a manner to stand upward in the arrangement direction of the wafer 200. That is, the nozzles 249a to 249c are respectively provided in a region horizontally surrounding the wafer arrangement region on the side of the wafer arrangement region in which the wafer 200 is arranged, in a manner to follow the wafer arrangement region. In plan view, the nozzle 249a is arranged in a manner to sandwich the center of the wafer 200 carried into the processing chamber 201 and to oppose the exhaust port 231a to be described later in a straight line. The nozzles 249b, 249c are arranged in a manner to sandwich the straight line L passing through the centers of the nozzle 249a and the exhaust port 231a from both sides, following the inner wall of the reaction tube 203 (the outer peripheral portion of the wafer 200). The straight line L is also a straight line passing through the center of the nozzle 249a and the wafer 200. That is, the nozzle 249c can also be provided on the side opposite to the nozzle 249b, sandwiching the straight line L. The nozzles 249b, 249c are arranged in a line-symmetrical manner with the straight line L as the axis of symmetry. On the side of the nozzles 249a to 249c, gas supply holes 250a to 250c for supplying gas are respectively provided. The gas supply holes 250a to 250c are respectively opened in a manner to oppose (face) the exhaust port 231a in plan view, and can supply gas toward the wafer 200. The gas supply holes 250a to 250c are provided in a plurality of numbers in the range from the lower portion to the upper portion of the reaction tube 203.

[0026] From the gas supply pipe 232a, a raw material gas is supplied into the processing chamber 201 via the MFC 241a, the valve 243a, and the nozzle 249a.

[0027] From the gas supply pipe 232b, a reaction gas is supplied into the processing chamber 201 via the MFC 241b, the valve 243b, and the nozzle 249b. Note that the reaction gas is a substance different in molecular structure (chemical structure) from the raw material gas.

[0028] From the gas supply pipes 232d, 232e, a non-reactive gas is supplied into the processing chamber 201 via the MFCs 241d, 241e, the valves 243d, 243e, the gas supply pipes 232a, 232b, and the nozzles 249a, 249b, respectively. In addition, from the gas supply pipe 232c, a non-reactive gas is supplied into the processing chamber 201 via the MFC 241c, the valve 243c, and the nozzle 249c. The non-reactive gas functions as a purge gas, a carrier gas, a dilution gas, and the like.

[0029] The raw material gas supply system is mainly composed of the gas supply pipe 232a, the MFC 241a, and the valve 243a. The reaction gas supply system is mainly composed of the gas supply pipe 232b, the MFC 241b, and the valve 243b. The non-reactive gas supply system is mainly composed of the gas supply pipes 232c to 232e, the MFCs 241c to 241e, and the valves 243c to 243e.

[0030] Note that each of the raw material gas and the reaction gas, or both of them, is also referred to as a film forming gas, and each of the raw material gas supply system and the reaction gas supply system, or both of them, is also referred to as a film forming gas supply system.

[0031] Any one or all of the above-described gas supply systems can also be configured as an integrated gas supply system 248 in which the valves 243a to 243e, the MFCs 241a to 241e, and the like are integrated. The integrated gas supply system 248 is configured in such a manner that each of the gas supply pipes 232a to 232e is connected, and the supply operation of the various gases into the gas supply pipes 232a to 232e, i.e., the opening and closing operation of the valves 243a to 243e, the flow rate adjustment operation by the MFCs 241a to 241e, and the like are controlled by the controller 121 described later. The integrated gas supply system 248 is configured as an integrated unit of a unitary type or a split type, and is configured in such a manner that it can be attached to and detached from the gas supply pipes 232a to 232e and the like as an integrated unit, and maintenance, replacement, addition, and the like of the integrated gas supply system 248 can be performed as an integrated unit.

[0032] Under the side wall of the reaction pipe 203, an exhaust port 231a for exhausting the atmosphere in the processing chamber 201 is provided. As shown in FIG. 1, the exhaust port 231a is connected to an exhaust system (not shown) via a pipe 231b. Figure 2As shown, the exhaust port 231a is provided at a position sandwiching the wafer 200 and opposing (facing) the nozzles 249a to 249c (gas supply holes 250a to 250c) in plan view. The exhaust port 231a can also be provided along the upper portion of the side wall of the reaction tube 203, that is, along the wafer arrangement region, from the lower portion. An exhaust pipe 231 is connected to the exhaust port 231a. The exhaust pipe 231 is composed of a metal material such as SUS. To the exhaust pipe 231, a vacuum pump 246 as a vacuum exhaust device is connected via a pressure sensor 245 as a pressure detector (pressure detection portion) that detects the pressure in the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 as a pressure regulator (pressure regulation portion). The APC valve 244 is configured in such a manner that, by opening and closing the valve in a state in which the vacuum pump 246 is operating, vacuum exhaust and vacuum exhaust stop in the processing chamber 201 can be performed, and, by adjusting the valve opening degree based on the pressure information detected by the pressure sensor 245 in a state in which the vacuum pump 246 is operating, the pressure in the processing chamber 201 can be adjusted. The exhaust system is mainly composed of the exhaust pipe 231, the APC valve 244, and the pressure sensor 245. It can be considered that the vacuum pump 246 is included in the exhaust system.

[0033] Below the manifold 209, a seal cover 219 as a furnace port cover is provided that airtightly seals the lower end opening of the manifold 209. The seal cover 219 is composed of a metal material such as SUS and is formed in a disc shape. An O-ring 220b as a seal member is provided on the upper surface of the seal cover 219 that abuts against the lower end of the manifold 209. Below the seal cover 219, a rotation mechanism 267 that rotates the wafer boat 217 described later is provided. A rotation shaft 255 of the rotation mechanism 267 is composed of a metal material such as SUS and penetrates the seal cover 219 to be connected to the wafer boat 217. The rotation mechanism 267 is configured to rotate the wafer 200 by rotating the wafer boat 217. The seal cover 219 is configured to be raised and lowered in the vertical direction by a wafer boat elevator 115 as a lifting mechanism provided outside the reaction tube 203. The wafer boat elevator 115 is configured as a conveyance device (conveyance mechanism) that carries the wafer 200 into and out of (conveys) the processing chamber 201 by raising and lowering the seal cover 219.

[0034] Below the manifold 209 is a gate 219s serving as a furnace opening cover. This gate 219s can airtightly seal the lower opening of the manifold 209 after the sealing cover 219 has been lowered and the crystal boat 217 has been removed from the processing chamber 201. The gate 219s is made of a metal material such as SUS and is formed in a disc shape. An O-ring 220c, serving as a sealing component, is provided on the upper surface of the gate 219s, abutting against the lower end of the manifold 209. The opening and closing actions (lifting, rotating, etc.) of the gate 219s are controlled by a gate opening and closing mechanism 115s.

[0035] The crystal boat 217, serving as a substrate support, is configured to hold multiple (e.g., 25 to 200) wafers 200 arranged horizontally with their centers aligned in the vertical direction and supported in a multi-layered manner, i.e., spaced apart. The crystal boat 217 is made of a heat-resistant material such as quartz or SiC. A heat-insulating plate 218, also made of a heat-resistant material such as quartz or SiC, is supported in multiple layers at the bottom of the crystal boat 217.

[0036] A temperature sensor 263, serving as a temperature detector, is installed inside the reaction tube 203. The energizing of the heater 207 is adjusted based on the temperature information detected by the temperature sensor 263, thereby achieving the desired temperature distribution within the processing chamber 201. The temperature sensor 263 is disposed along the inner wall of the reaction tube 203.

[0037] like Figure 3 As shown, the controller 121, which serves as the control unit (control means), is configured as a computer equipped with a CPU (Central Processing Unit) 121a, RAM (Random Access Memory) 121b, a storage device 121c, and an I / O port 121d. The RAM 121b, storage device 121c, and I / O port 121d are configured to exchange data with the CPU 121a via an internal bus 121e. An input / output device 122, such as a touch panel, is connected to the controller 121.

[0038] The storage device 121c is configured from, for example, a flash memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), or the like. In the storage device 121c, a control program that controls the operation of the substrate processing apparatus, a process recipe in which steps, conditions, and the like of the substrate processing described later are recorded, and the like are stored in a readable manner. The process recipe is a combination of modes in which the controller 121 executes each step in the substrate processing described later and can obtain a prescribed result, and functions as a program. Hereinafter, the process recipe, the control program, and the like are simply referred to as a program. In addition, the process recipe is simply referred to as a recipe. In this specification, the case where the term program is used includes the case where only the recipe is included, the case where only the control program is included, or the case where both are included. The RAM 121b is configured as a memory area (work area) that temporarily holds a program, data, and the like read by the CPU 121a.

[0039] The I / O port 121d is connected to the MFCs 241a to 241e, the valves 243a to 243e, the pressure sensor 245, the APC valve 244, the vacuum pump 246, the temperature sensor 263, the heater 207, the rotation mechanism 267, the boat elevator 115, the gate opening / closing mechanism 115s, and the like described above.

[0040] The CPU 121a is configured to read and execute the control program from the storage device 121c and read the recipe from the storage device 121c in accordance with the input of an operation command from the input / output device 122 or the like. The CPU 121a is configured to be able to control the following operations in accordance with the content of the recipe read: the flow rate adjustment operation of each gas by the MFCs 241a to 241e, the opening / closing operation of the valves 243a to 243e, the opening / closing operation of the APC valve 244, the pressure adjustment operation using 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 using the rotation mechanism 267, the raising and lowering operation of the boat 217 using the boat elevator 115, the opening / closing operation of the gate 219s using the gate opening / closing mechanism 115s, and the like.

[0041] The controller 121 is configured to install the aforementioned program stored in the external storage device 123 into a computer. The external storage device 123 includes, for example, a hard disk such as an HDD, an optical disk such as a CD, an optical disk such as an MO, a USB memory, and a semiconductor memory such as an SSD. The storage device 121c and the external storage device 123 are configured in the form of a computer-readable recording medium. Hereinafter, they will also be referred to collectively as recording media. In this specification, the term "recording medium" includes cases where only the storage device 121c is included, cases where only the external storage device 123 is included, or cases where both are included. It should be noted that the program can also be provided to the computer without using the external storage device 123, but using communication means such as the Internet or a dedicated line.

[0042] (2) Substrate processing process

[0043] Main use Figure 4 The following sequence example will be explained: This is an example of processing a wafer 200, which serves as a substrate, using the aforementioned substrate processing apparatus as a step in the manufacturing process of a semiconductor device; specifically, a film formation sequence example where a film is formed on the wafer 200. It should be noted that in this embodiment, the example of using a silicon substrate (silicon wafer) with recesses such as trenches and holes on its surface as the wafer 200 will be described. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 121.

[0044] In the film formation sequence of this method, a film is formed on the wafer 200 by performing step A (supplying raw material gas to the wafer 200 with recesses on its surface) and step B (supplying reaction gas to the wafer 200) alternately a predetermined number of times (n times, where n is an integer greater than or equal to 1).

[0045] It should be noted that in the film formation sequence of this method,

[0046] In step A, the raw material gas is supplied to the wafer 200 in multiple batches (m times, where m is an integer greater than or equal to 2), and the processing conditions during the initial supply of the raw material gas are set to suppress the self-decomposition of the raw material gas compared to the processing conditions during subsequent supply batches. It should be noted that, as an example, Figure 4 This illustrates the case where the raw material gas is intermittently supplied to the wafer 200 in three separate steps during step A (m=3).

[0047] For convenience, the film-forming sequence described above is sometimes shown as follows in this specification. The same wording is also used in the following variations and other descriptions.

[0048] (raw material gas × m → reactant gas) × n

[0049] It should be noted that, asFigure 4 As shown, it is preferable to insert a step of purging the processing chamber 201 between the step A and the step B when they are alternately performed n times (n is an integer of 1 or more). In addition, as shown, it is also preferable to insert a step of purging the processing chamber 201 between the m times of intermittently supplying the source gas. The film formation sequence in this case can be shown as follows. Figure 4

[0050] [(source gas → purge) x m → reactive gas → purge] x n

[0051] Note that, Figure 4 In the present embodiment, as an example of the film formation sequence in the present embodiment, an example of the timing of supplying each of the source gas, the reactive gas, and the non-reactive gas, and an example of the change in the partial pressure of the source gas accompanying this are shown.

[0052] In the present specification, the case where the term "wafer" is used includes the case where the wafer itself is indicated, and the case where a laminate of the wafer and a prescribed layer or film formed on the surface thereof is indicated. In the present specification, the case where the term "surface of the wafer" is used includes the case where the surface of the wafer itself is indicated, and the case where the surface of a prescribed layer or the like formed on the wafer is indicated. In the present specification, the case where it is described that a prescribed layer is formed on the wafer includes the case where the prescribed layer is formed directly on the surface of the wafer itself, and the case where the prescribed layer is formed on a layer or the like formed on the wafer. In the present specification, the case where the term "substrate" is used has the same meaning as the case where the term "wafer" is used.

[0053] (Wafer filling and boat loading)

[0054] After the plurality of wafers 200 are filled into the boat 217 (wafer filling), the gate 219s is moved by the gate opening / closing mechanism 115s so as to open the lower end opening of the manifold 209 (gate opening). Thereafter, as shown, Figure 1 The boat 217 on which the plurality of wafers 200 are supported is lifted by the boat elevator 115 and carried into the processing chamber 201 (boat loading). In this state, the seal cap 219 is in a state of sealing the lower end of the manifold 209 with the O-ring 220b.

[0055] (Pressure adjustment and temperature adjustment)

[0056] ​After the end of the boat loading, vacuum evacuation (reduced pressure evacuation) is performed using the vacuum pump 246 to bring the inside of the processing chamber 201, i.e., the space in which the wafer 200 is present, to a desired pressure (degree of vacuum). At this time, the pressure in the processing chamber 201 is measured by the pressure sensor 245, and feedback control (pressure adjustment) is performed on the APC valve 244 based on the measured pressure information. In addition, heating is performed using the heater 207 to bring the wafer 200 in the processing chamber 201 to a desired processing temperature. At this time, feedback control (temperature adjustment) is performed on the energization of the heater 207 based on the temperature information detected by the temperature sensor 263 to bring the inside of the processing chamber 201 to a desired temperature distribution. In addition, the rotation of the wafer 200 using the rotation mechanism 267 is started. The evacuation of the inside of the processing chamber 201, the heating, and the rotation of the wafer 200 are all continued at least until the processing of the wafer 200 ends.

[0057] (Film formation processing)

[0058] After that, the following steps A and B are sequentially performed.

[0059] [Step A]

[0060] In this step, the wafer 200 in the processing chamber 201 is supplied with a raw material gas in multiple stages. Specifically, the step al of supplying the wafer 200 with a raw material gas and the step a2 of purging the inside of the processing chamber 201, which is the space in which the wafer 200 is present, are alternately repeated multiple times (m times, m is an integer of 2 or more).

[0061] In the step al, the valve 243a is opened, and a raw material gas is caused to flow into the gas supply pipe 232a. The raw material gas is flow-adjusted by the MFC 241a, supplied into the processing chamber 201 via the nozzle 249a, and exhausted from the exhaust port 231a. At this time, the wafer 200 is supplied with the raw material gas (raw material gas supply). At this time, the valves 243c to 243e are opened, and a non-reactive gas is supplied into the processing chamber 201 via the nozzles 249a to 249c, respectively. Note that in the several methods shown below, the supply of the non-reactive gas into the processing chamber 201 can not be performed.

[0062] In the step a2, the valve 243a is closed, and the supply of the raw material gas into the processing chamber 201 is stopped. Then, the inside of the processing chamber 201 is vacuum-evacuated, and the gas or the like remaining in the processing chamber 201 is exhausted from the processing chamber 201. At this time, the valves 243c to 243e are opened, and a non-reactive gas is supplied into the processing chamber 201 as a purge gas, and is exhausted from the exhaust port 231a, whereby the inside of the processing chamber 201 is purged with the non-reactive gas (purging).

[0063] In a case where, for example, a chlorosilane gas described later is used as the source gas, a SiCl-containing layer is formed on the wafer 200 by repeating steps al and a2 alternately a predetermined number of times under the processing conditions described later. The SiCl-containing layer is formed by physical adsorption and chemical adsorption of molecules of the chlorosilane gas to the surface of the wafer 200, physical adsorption and chemical adsorption of molecules of a substance obtained by partial decomposition of the chlorosilane gas to the surface of the wafer 200, and deposition of Si on the surface of the wafer 200 due to thermal decomposition of the chlorosilane gas, and the like. The SiCl-containing layer can be an adsorption layer (a physical adsorption layer, a chemical adsorption layer) of molecules of the chlorosilane gas or molecules of a substance obtained by partial decomposition of the chlorosilane gas, or can be a deposition layer of Si containing Cl. In a case where the chemical adsorption layer described above or the deposition layer described above is formed on the surface of the wafer 200, Si contained in the chlorosilane gas is adsorbed to the surface of the wafer 200. In this specification, the SiCl-containing layer is also referred to simply as a Si-containing layer.

[0064] As the source gas, for example, a silane-based gas containing Si as a main element constituting a film formed on the wafer 200 can be used. As the silane-based gas, for example, a gas containing Si and a halogen, that is, a halosilane gas can be used. The halogen includes chlorine (Cl), fluorine (F), bromine (Br), iodine (I), and the like. As the halosilane gas, for example, a chlorosilane gas containing Si and Cl can be used.

[0065] As the source gas, for example, a monochlorosilane (SiH3Cl, abbreviated as: MCS) gas, a dichlorosilane (SiH2Cl2, abbreviated as: DCS) gas, a trichlorosilane (SiHCl3, abbreviated as: TCS) gas, a tetrachlorosilane (SiCl4, abbreviated as: STC) gas, a hexachlorodisilane (Si2Cl6, abbreviated as: HCDS) gas, an octachloropropylsilane (Si3Cl8, abbreviated as: OCTS) gas, or the like can be used. As the source gas, one or more of these can be used.

[0066] As the source gas, in addition to the chlorosilane gas, for example, a tetrafluorosilane (SiF4) gas, a difluorosilane (SiH2F2) gas, or the like can be used as a fluorosilane gas, a tetrabromosilane (SiBr4) gas, a dibromosilane (SiH2Br2) gas, or the like can be used as a bromosilane gas, a tetraiodosilane (SiI4) gas, a diiodosilane (SiH2I2) gas, or the like can be used as an iodosilane gas. As the source gas, one or more of these can be used.

[0067] As the source gas, in addition to these, for example, a gas containing Si and an amino group, that is, an amino silane gas can also be used. The amino group is a monovalent functional group obtained by removing a hydrogen (H) from ammonia, a primary amine, or a secondary amine, and can be represented as -NH2, -NHR, -NR2. Note that R represents an alkyl group, and the two R's in -NR2may be the same or different.

[0068] As the source gas, for example, a tetra(dimethylamino)silane (Si[N(CH3)2]4, abbreviated as 4DMAS) gas, a tri(dimethylamino)silane (Si[N(CH3)2]3H, abbreviated as 3DMAS) gas, a bis(diethylamino)silane (Si[N(C2H5)2]2H2, abbreviated as BDEAS) gas, a bis(tert-butylamino)silane (SiH2[NH(C4H9)]2, abbreviated as BTBAS) gas, a (diisopropylamino)silane (SiH3[N(C3H7)2], abbreviated as DIPAS) gas, or the like amino silane gas can also be used. As the source gas, one or more of these can be used.

[0069] As the non-active gas, for example, a nitrogen (N2) gas, an argon (Ar) gas, a helium (He) gas, a neon (Ne) gas, a xenon (Xe) gas, or the like noble gas can be used. As the non-active gas, one or more of these can be used. This is also the same in each of the steps described later.

[0070] [Step B]

[0071] After the end of Step A, a reaction gas is supplied to the wafer 200 in the processing chamber 201, that is, to the Si-containing layer as the first layer formed on the wafer 200.

[0072] Specifically, the valve 243b is opened, and a reaction gas is caused to flow into the gas supply pipe 232b. The reaction gas is flow-regulated by the MFC 241b, supplied into the processing chamber 201 via the nozzle 249b, and exhausted from the exhaust port 231a. At this time, the reaction gas is supplied to the wafer 200 (reaction gas supply). At this time, the valves 243c to 243e are opened, and a non-active gas is supplied into the processing chamber 201 via the nozzles 249a to 249c, respectively. Note that in several methods shown below, the supply of the non-active gas into the processing chamber 201 can not be performed.

[0073] In a case where, for example, a nitriding gas described later is used as the reaction gas, at least a part of the Si-containing layer formed on the wafer 200 is nitrided (modified) by supplying the nitriding gas to the wafer 200 under the processing conditions described later. As a result, on the surface of the wafer 200 as the base, as the second layer, a layer in which the Si-containing layer is nitrided, that is, a silicon nitride layer (SiN layer) as a layer containing Si and N is formed. At the time of forming the SiN layer, the impurities such as Cl included in the Si-containing layer become a gaseous substance containing at least Cl in the course of the modification reaction of the Si-containing layer by the nitriding gas, and are exhausted from the processing chamber 201. Thus, the SiN layer becomes a layer having less impurities such as Cl than the Si-containing layer formed in Step A.

[0074] After the SiN layer as the second layer is formed, the valve 243b is closed, and the supply of the nitriding gas into the processing chamber 201 is stopped. Then, by the same processing step as the purge in Step A, the gas and the like remaining in the processing chamber 201 is exhausted (purged) from the processing chamber 201.

[0075] As the reaction gas, for example, a gas containing nitrogen (N) and hydrogen (H) as a nitriding gas (nitriding agent) can be used. The gas containing N and H is also a gas containing N and also a gas containing H. The gas containing N and H preferably has an N-H bond.

[0076] As the reaction gas, for example, a nitriding hydrogen-based gas such as ammonia (NH3) gas, diazene (N2H2) gas, hydrazine (N2H4) gas, N3H8 gas, or the like can be used. As the reaction gas, one or more of them can be used.

[0077] As the reaction gas, in addition to these, for example, a gas containing nitrogen (N), carbon (C), and hydrogen (H) can be used. As the gas containing N, C, and H, for example, an amine-based gas, an organic hydrazine-based gas can be used. The gas containing N, C, and H is also a gas containing N, also a gas containing C, also a gas containing H, and also a gas containing N and C.

[0078] As the reaction gas, for example, ethylamine-based gas such as monomethylamine (C2H5NH2, abbreviated as: MEA) gas, dimethylamine ((C2H5)2NH, abbreviated as: DEA) gas, trimethylamine ((C2H5)3N, abbreviated as: TEA) gas, methylamine-based gas such as monomethylamine (CH3NH2, abbreviated as: MMA) gas, dimethylamine ((CH3)2NH, abbreviated as: DMA) gas, trimethylamine ((CH3)3N, abbreviated as: TMA) gas, organic hydrazine-based gas such as monomethylhydrazine ((CH3)HN2H2, abbreviated as: MMH) gas, dimethylhydrazine ((CH3)2N2H2, abbreviated as: DMH) gas, trimethylhydrazine ((CH3)2N2(CH3)H, abbreviated as: TMH) gas, or the like can be used. One or more of them can be used as the reaction gas.

[0079] [Prescribed number of times]

[0080] By performing the above-described cycles of steps A and B non-simultaneously, that is, asynchronously, for a prescribed number of times (n times, n is an integer of 1 or more), it is possible to form, for example, a silicon nitride film (SiN film) as a film on the surface of the wafer 200. The above-described cycles are preferably repeated a plurality of times. That is, it is preferable to make the thickness of the SiN layer formed in each cycle thinner than the desired film thickness, to repeat the above-described cycles a plurality of times until the thickness of the SiN film formed by laminating the SiN layers becomes the desired thickness. Note that, in the case where a gas containing N, C, and H is used as the reaction gas, it is also possible to form, for example, a silicon carbon nitride layer (SiCN layer) as the second layer, and by performing the above-described cycles for a prescribed number of times, it is also possible to form, for example, a silicon carbon nitride film (SiCN film) as a film on the surface of the wafer 200.

[0081] Note that, as described above, in the present mode, it is preferable to supply the source gas in multiple stages (m stages, m is an integer of 2 or more) in step A. At this time, when the source gas is intermittently pulsed in multiple stages in step A, it is preferable to set the processing conditions at the time of the initial supply of the source gas to processing conditions that can suppress self-decomposition (gas-phase decomposition) of the source gas as compared to the processing conditions at the time of the second or subsequent supply of the source gas.

[0082] For example, in step A, the source gas is supplied in multiple stages, at which time it is preferable to set the processing conditions at the time of the initial supply of the source gas to processing conditions that can suppress the generation of intermediates of the source gas as compared to the processing conditions at the time of the second or subsequent supply of the source gas.

[0083] For example, in step A, the raw material gas is supplied in multiple stages, and in this case, it is preferable that the processing conditions at the time of initial supply of the raw material gas be set to processing conditions that can suppress the self-decomposition of the raw material gas, and the processing conditions at the time of supply of the raw material gas after the second time be set to processing conditions that allow the self-decomposition of the raw material gas.

[0084] For example, in step A, the raw material gas is supplied in multiple stages, and in this case, it is preferable that the processing conditions at the time of initial supply of the raw material gas be set to processing conditions that can suppress the generation of intermediates of the raw material gas, and the processing conditions at the time of supply of the raw material gas after the second time be set to processing conditions that allow the generation of intermediates of the raw material gas.

[0085] For example, in step A, the raw material gas is supplied in multiple stages, and in this case, it is preferable that the duration of supply of the raw material gas at the time of initial supply of the raw material gas be shorter than the duration of supply of the raw material gas at the time of supply of the raw material gas after the second time.

[0086] For example, in step A, the raw material gas is supplied in multiple stages, and in this case, it is preferable that the flow rate of supply of the raw material gas at the time of initial supply of the raw material gas be lower than the flow rate of supply of the raw material gas at the time of supply of the raw material gas after the second time.

[0087] For example, in step A, the raw material gas is supplied in multiple stages, and in this case, it is preferable that a non-reactive gas be supplied as a carrier gas at the time of supply of the raw material gas to the wafer 200, and the flow rate of supply of the carrier gas at the time of initial supply of the raw material gas be higher than the flow rate of supply of the carrier gas at the time of supply of the raw material gas after the second time.

[0088] For example, in step A, the raw material gas is supplied in multiple stages, and in this case, it is preferable that the partial pressure of the raw material gas at the time of initial supply of the raw material gas be lower than the partial pressure of the raw material gas at the time of supply of the raw material gas after the second time.

[0089] For example, in step A, the raw material gas is supplied in multiple stages, and in this case, it is preferable that the pressure of the space in which the wafer 200 is present, i.e., the pressure in the processing chamber 201, at the time of initial supply of the raw material gas be lower than the pressure in the processing chamber 201 at the time of supply of the raw material gas after the second time.

[0090] Note that, in step A, the raw material gas is supplied in multiple stages, and in this case, the pressure in the processing chamber 201 at the time of initial supply of the raw material gas can also be set to a pressure that is higher than the pressure in the processing chamber 201 at the time of supply of the raw material gas after the second time. However, in this case, it is preferable that the flow rate of supply of the non-reactive gas supplied into the processing chamber 201 at the time of initial supply of the raw material gas be higher than the flow rate of supply of the non-reactive gas supplied into the processing chamber 201 at the time of supply of the raw material gas after the second time, so that the partial pressure of the raw material gas at the time of initial supply of the raw material gas is lower than the partial pressure of the raw material gas at the time of supply of the raw material gas after the second time.

[0091] As described above, in the step A, the source gas is supplied in multiple (m times, m is an integer of 2 or more) stages, at this time, by setting the processing conditions at the time of the initial supply of the source gas to processing conditions that can suppress self-decomposition of the source gas compared to the processing conditions at the time of the second or later supply of the source gas, it is possible to suppress the self-decomposition of the source gas at the initial stage of the step A, that is, at the initial stage of the supply of the source gas, and to uniformly adsorb the atoms or molecules contained in the source gas to the entire region inside the recess provided on the surface of the wafer 200. That is, it is possible to uniformly adsorb the atoms or molecules contained in the source gas to the entire region of the initial adsorption sites on the surface of the recess at the initial stage of the supply of the source gas. As a result, as shown in (a) of FIG. 10, it is possible to form a Si-containing layer having a uniform thickness, that is, a Si-containing layer having a high step coverage, as an initial layer on the entire region inside the recess on the surface of the wafer 200. This layer sometimes becomes a continuous layer, and sometimes becomes a discontinuous layer. In either case, it becomes a layer having a high step coverage. Figure 5

[0092] Thus, by forming a Si-containing layer having high uniformity and a high step coverage as an initial layer on the region inside the recess that is in contact with the surface, even in the case where the processing conditions are changed later, the Si-containing layer formed later also has a tendency to inherit the high uniformity and the high step coverage of the initial layer, and then becomes a layer having high uniformity and a high step coverage.

[0093] Further, in the step A, the source gas is supplied in multiple (m times, m is an integer of 2 or more) stages, at this time, by setting the processing conditions at the time of the second or later supply of the source gas to processing conditions that allow self-decomposition of the source gas compared to the processing conditions at the time of the initial supply of the source gas, it is possible to relax the degree of suppression of the self-decomposition of the source gas at the time of the second or later supply of the source gas, for example, to allow self-decomposition of the source gas, and to effectively adsorb the atoms or molecules contained in the source gas to the entire region inside the recess. That is, it is possible to form a Si-containing layer at a higher formation rate on the surface of the recess in which the initial layer is formed. As for the Si-containing layer formed at this time, since it is obtained after the Si-containing layer having a high step coverage is formed as an initial layer, it has a tendency to inherit the characteristics and the state of the initial layer, and then has a high step coverage.

[0094] As a result, as shown in (b) of FIG. 11, it is possible to form a uniform and conformal first layer (Si-containing layer) on the entire region inside the recess provided on the surface of the wafer 200 without reducing the formation rate of the Si-containing layer. As a result, it is possible to improve the step coverage without reducing the film formation rate of the film formed on the wafer 200, and to form a uniform and conformal film on the entire region inside the recess provided on the surface of the wafer 200. Figure 5 As a result, as shown in (b) of FIG. 11, it is possible to form a uniform and conformal first layer (Si-containing layer) on the entire region inside the recess provided on the surface of the wafer 200 without reducing the formation rate of the Si-containing layer. As a result, it is possible to improve the step coverage without reducing the film formation rate of the film formed on the wafer 200, and to form a uniform and conformal film on the entire region inside the recess provided on the surface of the wafer 200.​

[0095] Note that the reason will be described later, in the case where the raw material gas is supplied in multiple stages (m times, m is an integer of 2 or more) in Step A, it is preferable that the time of the step a2 of purging the inside of the processing chamber 201 performed after the step al of supplying the raw material gas for the first time (first time) be shorter than the time of the step a2 of purging the inside of the processing chamber 201 performed after the step al of supplying the raw material gas for the last time (mth time).

[0096] In addition, in the case where the raw material gas is supplied in multiple stages (m times, m is an integer of 2 or more) in Step A, it is preferable that the time of the step a2 of purging the inside of the processing chamber 201 performed after the step al of supplying the raw material gas for the second time be shorter than the time of the step a2 of purging the inside of the processing chamber 201 performed after the step al of supplying the raw material gas for the last time (mth time). Note that in this case, it is preferable that the time of the step a2 of purging the inside of the processing chamber 201 performed after the step al of supplying the raw material gas for each of the first to (m-1)th times be shorter than the time of the step a2 of purging the inside of the processing chamber 201 performed after the step al of supplying the raw material gas for the last time (mth time).

[0097] In addition, in the case where the raw material gas is supplied in multiple stages (m times, m is an integer of 2 or more) in Step A, it is preferable that the time of the step a2 of purging the inside of the processing chamber 201 performed after the step al of supplying the raw material gas for the last time (mth time) be the longest among the times of the step a2 of purging the inside of the processing chamber 201 performed after the step al of supplying the raw material gas for each of the multiple times.

[0098] The following examples are the processing conditions of each of the above steps in the case where, for example, a chlorosilane gas is used as the raw material gas and, for example, a gas containing N and H is used as the reaction gas. Note that the expression of a numerical range such as "1 to 100 Pa" in this specification means that the lower limit value and the upper limit value are included in the range. Therefore, for example, "1 to 100 Pa" means "1 Pa or more and 100 Pa or less". The same applies to other numerical ranges. In addition, the processing temperature in this specification means the temperature of the wafer 200, and the processing pressure means the pressure in the processing chamber 201. In addition, the gas supply flow rate: 0 sccm means the case where the gas is not supplied. The same applies to these in the following description.

[0099] As the processing conditions when the step al is performed for the first time in Step A, for example, the following can be exemplified:

[0100] Chlorosilane gas supply flow rate: 1 to 500 sccm, preferably 1 to 200 sccm

[0101] Chlorosilane gas supply duration: 1 to 20 seconds, preferably 1 to 10 seconds

[0102] Non-active gas supply flow rate: 500 to 30,000 seem, preferably 1,000 to 20,000 seem

[0103] Treatment temperature: 250 to 800°C, preferably 600 to 700°C

[0104] Treatment pressure: 1 to 2,666 Pa, preferably 1 to 1,333 Pa, more preferably 1 to 100 Pa

[0105] Chlorosilane gas partial pressure: 0.00003 to 1,333 Pa, preferably 0.00005 to 222 Pa, more preferably 0.00005 to 17 Pa.

[0106] As the treatment conditions when step a2 is performed for the first time to the (m-1)th time in step A, for example, the following can be given:

[0107] Chlorosilane gas supply flow rate: 1 to 2,000 seem, preferably 10 to 1,000 seem

[0108] Chlorosilane gas supply duration: 5 to 40 seconds, preferably 10 to 30 seconds Non-active gas supply flow rate: 0 to 20,000 seem, preferably 500 to 10,000 seem

[0109] Treatment pressure: 1 to 2,666 Pa, preferably 67 to 1,333 Pa

[0110] Chlorosilane gas partial pressure: 0.00005 to 2,666 Pa, preferably 0.06 to 889 Pa.

[0111] The other treatment conditions can be set to the same treatment conditions as those when step a1 is performed for the first time in step A.

[0112] As the treatment conditions when step a2 is performed for the first time to the (m-1)th time in step A, for example, the following can be given:

[0113] Non-active gas supply flow rate: 1,000 to 20,000 seem

[0114] Non-active gas supply duration: 1 to 20 seconds, preferably 1 to 10 seconds.

[0115] The other treatment conditions can be set to the same treatment conditions as those when step a1 is performed for the first time in step A.

[0116] As the treatment conditions when step a2 is performed for the first time to the (m-1)th time in step A, for example, the following can be given:

[0117] Non-active gas supply flow rate: 1,000 to 20,000 seem

[0118] Non-reactive gas supply duration: 5 to 60 seconds, preferably 10 to 30 seconds

[0119] The other processing conditions can be set to be the same as the processing conditions at the time of the first step al in Step A.

[0120] Note that, at the time of the last (mth) step a2 in Step A, the non-reactive gas supply into the processing chamber 201 and the exhaust of the processing chamber 201 in the state where the non-reactive gas supply into the processing chamber 201 is stopped can be repeated plural times. That is, at the time of the last (mth) step a2 in Step A, the cyclic purge can be performed.

[0121] As the processing conditions of Step B, for example, the following can be shown:

[0122] N and H-containing gas supply flow rate: 1 to 20,000 seem, preferably 1,000 to 10,000 seem

[0123] N and H-containing gas supply duration: 1 to 120 seconds, preferably 1 to 60 seconds Non-reactive gas supply flow rate: 0 to 20,000 seem, preferably 500 to 10,000 seem

[0124] Processing pressure: 1 to 4,000 Pa, preferably 1 to 3,000 Pa.

[0125] The other processing conditions can be set to be the same as the processing conditions at the time of the first step al in Step A.

[0126] (Post-purge and atmospheric pressure recovery)

[0127] After the formation of the film of the desired thickness onto the wafer 200 is completed, the non-reactive gas as the purge gas is supplied from each of the nozzles 249a to 249c into the processing chamber 201, and is exhausted from the exhaust port 231a. Thereby, the processing chamber 201 is purged, and the gas, reaction by-products, and the like remaining in the processing chamber 201 are removed from the processing chamber 201 (post-purge). Then, the atmosphere in the processing chamber 201 is replaced with the non-reactive gas (non-reactive gas replacement), and the pressure in the processing chamber 201 is recovered to the normal pressure (atmospheric pressure recovery).

[0128] (Carrier unloading and wafer extraction)

[0129] Then, the seal cap 219 is lowered by the boat lifter 115, and the lower end of the manifold 209 is opened. Then, the processed wafer 200 is carried out from the lower end of the manifold 209 to the outside of the reaction tube 203 in a state of being supported by the boat 217 (boat unloading). After the boat unloading, the gate 219s is moved, and the lower end of the manifold 209 is sealed by the O-ring 220c by the gate 219s (gate closing). The processed wafer 200 is taken out from the boat 217 after being carried out to the outside of the reaction tube 203 (wafer taking out).

[0130] (3) Effects brought by the present embodiment

[0131] According to the present embodiment, one or more of the following effects can be obtained.

[0132] (a) In step A, the raw material gas is supplied in multiple stages, and at this time, by setting the processing conditions at the time of initial supply of the raw material gas to processing conditions that can suppress the self-decomposition of the raw material gas as compared to the processing conditions at the time of the second or later supply of the raw material gas, the self-decomposition of the raw material gas can be suppressed at the initial stage of the supply of the raw material gas, and the atoms or molecules contained in the raw material gas can be uniformly adsorbed to the entire region inside the recess. Thereafter, the degree of suppression of the self-decomposition of the raw material gas can be relaxed as compared to before, for example, the self-decomposition of the raw material gas is permitted, and the atoms or molecules contained in the raw material gas can be effectively adsorbed to the entire region inside the recess. As a result, the step coverage can be improved without reducing the film formation rate of the film formed on the wafer 200. In addition, the wafer-in-plane film thickness uniformity of the film formed on the wafer 200 can be improved, for example, the deviation in film thickness is reduced among the upper side surface, the middle side surface, the lower side surface, and the bottom of the recess.

[0133] (b) In step A, the raw material gas is supplied in multiple stages, and at this time, by setting the processing conditions at the time of initial supply of the raw material gas to processing conditions that can suppress the generation of intermediates of the raw material gas as compared to the processing conditions at the time of the second or later supply of the raw material gas, the generation of intermediates of the raw material gas can be suppressed at the initial stage of the supply of the raw material gas, and the atoms or molecules contained in the raw material gas can be uniformly adsorbed to the entire region inside the recess. Thereafter, the degree of suppression of the generation of intermediates of the raw material gas can be relaxed as compared to before, for example, the generation of intermediates of the raw material gas is permitted, and the atoms or molecules contained in the raw material gas can be effectively adsorbed to the entire region inside the recess. As a result, the step coverage can be improved without reducing the film formation rate of the film formed on the wafer 200. In addition, the wafer-in-plane film thickness uniformity of the film formed on the wafer 200 can be improved.

[0134] (c) In step A, the raw material gas is supplied in multiple stages, and at this time, by setting the processing conditions at the time of initial supply of the raw material gas to processing conditions capable of suppressing self-decomposition of the raw material gas, and setting the processing conditions at the time of supply of the raw material gas after the second time to processing conditions in which the raw material gas self-decomposes, the generation of intermediates of the raw material gas can be suppressed at the initial stage of supply of the raw material gas, and the atoms or molecules contained in the raw material gas can be uniformly adsorbed to the entire region inside the recess. Thereafter, the raw material gas can self-decompose, and the atoms or molecules contained in the raw material gas can be effectively adsorbed to the entire region inside the recess. As a result, the step coverage can be improved without reducing the film formation rate of the film formed on the wafer 200. In addition, the film thickness uniformity in the wafer surface of the film formed on the wafer 200 can be improved. Note that according to this method, the adsorption efficiency of the atoms or molecules contained in the raw material gas into the recess at the time of supply of the raw material gas after the second time can be improved, and the film formation rate can be further improved.

[0135] (d) In step A, the raw material gas is supplied in multiple stages, and at this time, by setting the processing conditions at the time of initial supply of the raw material gas to processing conditions capable of suppressing the generation of intermediates of the raw material gas, and setting the processing conditions at the time of supply of the raw material gas after the second time to processing conditions in which intermediates of the raw material gas are generated, the generation of intermediates of the raw material gas can be suppressed at the initial stage of supply of the raw material gas, and the atoms or molecules contained in the raw material gas can be uniformly adsorbed to the entire region inside the recess. Thereafter, intermediates of the raw material gas can be generated, and the atoms or molecules contained in the raw material gas can be effectively adsorbed to the entire region inside the recess. As a result, the step coverage can be improved without reducing the film formation rate of the film formed on the wafer 200. In addition, the film thickness uniformity in the wafer surface of the film formed on the wafer 200 can be improved. Note that according to this method, the adsorption efficiency of the atoms or molecules contained in the raw material gas into the recess at the time of supply of the raw material gas after the second time can be improved, and the film formation rate can be further improved.

[0136] (e) In step A, the raw material gas is supplied in multiple stages, and at this time, by making the supply duration of the raw material gas at the time of initial supply of the raw material gas shorter than the supply duration of the raw material gas at the time of supply of the raw material gas after the second time, the self-decomposition of the raw material gas can be suppressed at the initial stage of supply of the raw material gas. Thereafter, the degree of suppression of the self-decomposition of the raw material gas can be relaxed, and the time for adsorbing the atoms or molecules contained in the raw material gas into the recess can be relatively extended. As a result, the step coverage can be improved without reducing the film formation rate of the film formed on the wafer 200. In addition, the film thickness uniformity in the wafer surface of the film formed on the wafer 200 can be improved.

[0137] (f) In step A, the source gas is supplied in multiple stages, and at this time, by making the supply flow rate of the source gas when the source gas is first supplied smaller than the supply flow rate of the source gas when the source gas is supplied for the second time or later, the self-decomposition of the source gas can be suppressed at the initial stage of the source gas supply. Thereafter, the degree of suppression of the self-decomposition of the source gas can be eased, and the supply flow rate of the carrier gas when the atoms or molecules contained in the source gas are adsorbed in the recesses can be relatively increased. As a result, the step coverage can be improved without reducing the film formation rate of the film formed on the wafer 200. In addition, the film thickness uniformity in the wafer surface of the film formed on the wafer 200 can be improved.

[0138] (g) In step A, the source gas is supplied in multiple stages, and at this time, by supplying a non-reactive gas as a carrier gas when the source gas is supplied to the wafer 200, and making the supply flow rate of the carrier gas when the source gas is first supplied larger than the supply flow rate of the carrier gas when the source gas is supplied for the second time or later, the self-decomposition of the source gas can be suppressed at the initial stage of the source gas supply. Thereafter, the degree of suppression of the self-decomposition of the source gas can be eased, and the supply flow rate of the carrier gas when the atoms or molecules contained in the source gas are adsorbed in the recesses can be relatively decreased, thereby causing the atoms or molecules contained in the source gas to be effectively adsorbed in the entire area of the recesses. As a result, the step coverage can be improved without reducing the film formation rate of the film formed on the wafer 200. In addition, the film thickness uniformity in the wafer surface of the film formed on the wafer 200 can be improved.

[0139] (h) In step A, the source gas is supplied in multiple stages, and at this time, by making the partial pressure of the source gas when the source gas is first supplied lower than the partial pressure of the source gas when the source gas is supplied for the second time or later, the self-decomposition of the source gas can be suppressed at the initial stage of the source gas supply. Thereafter, the degree of suppression of the self-decomposition of the source gas can be eased, and the partial pressure of the source gas when the atoms or molecules contained in the source gas are adsorbed in the recesses can be relatively increased, thereby causing the atoms or molecules contained in the source gas to be effectively adsorbed in the entire area of the recesses. As a result, the step coverage can be improved without reducing the film formation rate of the film formed on the wafer 200. In addition, the film thickness uniformity in the wafer surface of the film formed on the wafer 200 can be improved.

[0140] (i) In step A, the source gas is supplied in multiple stages, and in this case, by making the pressure of the space in which the wafer 200 is present (the pressure in the processing chamber 201) at the time of initial supply of the source gas lower than the pressure in the processing chamber 201 at the time of the second or later supply of the source gas, it is possible to suppress the self-decomposition of the source gas at the initial stage of source gas supply. Thereafter, the degree of suppression of the self-decomposition of the source gas can be relaxed, and the pressure in the processing chamber 201 when the atoms or molecules contained in the source gas are adsorbed in the recesses is relatively increased, whereby the atoms or molecules contained in the source gas are effectively adsorbed in the entire region of the recesses. As a result, it is possible to increase the step coverage without reducing the film formation rate of the film formed on the wafer 200. In addition, it is possible to increase the film thickness uniformity in the wafer surface of the film formed on the wafer 200.

[0141] Note that, in step A, the source gas is supplied in multiple stages, and in this case, the pressure in the processing chamber 201 at the time of initial supply of the source gas can also be set to a pressure higher than the pressure in the processing chamber 201 at the time of the second or later supply of the source gas. In this case, by making the supply flow rate of the inactive gas supplied into the processing chamber 201 at the time of initial supply of the source gas greater than the supply flow rate of the inactive gas supplied into the processing chamber 201 at the time of the second or later supply of the source gas, it is possible to make the partial pressure of the source gas at the time of initial supply of the source gas lower than the partial pressure of the source gas at the time of the second or later supply of the source gas, and it is possible to obtain the same effects as the above.

[0142] (j) In step A, by repeating steps al and a2 alternately a plurality of times, even in the case where an intermediate is generated midway through the source gas supply, it is possible to efficiently remove the intermediate and adsorb the atoms or molecules contained in the source gas in the recesses. That is, it is possible to suppress the film formation inhibition caused by the generation of excess intermediate. As a result, it is possible to increase the step coverage without reducing the film formation rate of the film formed on the wafer 200. In addition, it is possible to increase the film thickness uniformity in the wafer surface of the film formed on the wafer 200.

[0143] (k) As described above, according to the present mode, it is possible to increase the step coverage of the film formed on the wafer 200. For example, according to the present mode, it is possible to obtain a step coverage of at least 70%. In addition, for example, according to any of the above methods in the present mode, it is possible to obtain a step coverage of 80% or more. In addition, for example, according to any of the above methods in the present mode, it is possible to obtain a step coverage of 85% or more. Furthermore, for example, according to any of the above methods in the present mode, it is possible to obtain a step coverage of 90% or more.

[0144] (l) In step A, the source gas is supplied in multiple (m times, m is an integer of 2 or more) stages, and at this time, by making the time of step a2 performed first (first time) shorter than the time of step a2 performed last (mth time), the total purge time can be shortened, and the decrease in film formation rate can be suppressed.

[0145] (m) In step A, the source gas is supplied in multiple (m times, m is an integer of 2 or more) stages, and at this time, in the case where m > 3, by making the time of step a2 performed second (second time) shorter than the time of step a2 performed last (mth time), the total purge time can be shortened, and the decrease in film formation rate can be suppressed. In this case, the time of step a2 performed in each of the first to (m-1)th times can also be made shorter than the time of step a2 performed last (mth time), whereby the total purge time can be shortened, and the decrease in film formation rate can be suppressed.

[0146] (n) In step A, the source gas is supplied in multiple (m times, m is an integer of 2 or more) stages, and at this time, by making the time of step a2 performed last (mth time) in the multiple times of step a2 the longest, the total purge time can be shortened, and the decrease in film formation rate can be suppressed. In addition, in step A, the residual of the source gas in the processing chamber 201 after the end of step a1 performed last (mth time) in the multiple times of step a1 can be sufficiently suppressed. As a result, when step B is performed thereafter, the mixing of the source gas and the reaction gas in the processing chamber 201 can be avoided, and the generation of particles can be suppressed. Thus, the film quality of the film formed on the wafer 200 can be improved.

[0147] Note that, in step A, when the source gas is supplied in multiple (m times, m is an integer of 2 or more) stages, the reaction gas is supplied to the processing chamber 201 immediately after the end of step a2 performed last (mth time). Therefore, in order to avoid the generation of particles due to the mixing of the source gas remaining in the processing chamber 201 and the reaction gas supplied to the processing chamber 201, step a2 performed last (mth time) needs to be performed sufficiently. In contrast, the source gas is supplied to the processing chamber 201 immediately after the end of step a2 performed in each of the first to (m-1)th times. Therefore, although there is a possibility that the source gas remaining in the processing chamber 201 and the source gas supplied to the processing chamber 201 mix, even in the case where they mix, since they are the same substance as each other, particles are not generated. Therefore, as for step a2 performed in each of the first to (m-1)th times, the purge time can be shortened as compared with step a2 performed last (mth time).

[0148] (o) In the case where the above-described various source gases, the above-described reaction gas, and the above-described various non-reactive gases are used, the above-described effects can be similarly obtained. Among them, the above-described effects can be remarkably obtained in the case where a halogenated silane gas is used as the source gas. In addition, the above-described effects can be particularly remarkably obtained in the case where a chlorosilane gas is used as the source gas.

[0149] <Other modes of the present disclosure>

[0150] The above describes the modes of the present disclosure in detail. However, the present disclosure is not limited to the above-described modes, and various modifications can be made within the scope of the gist thereof.

[0151] For example, as the reaction gas, in addition to the above-described gas containing N and H, the gas containing N, C, and H, for example, a carbon (C) containing gas such as ethylene (C2H4) gas, acetylene (C2H2) gas, propylene (C3H6) gas, and the like, a boron (B) containing gas such as diborane (B2H6) gas, trichloroborane (BC13) gas, and the like, an oxygen (O) containing gas such as oxygen (O2) gas, ozone (O3) gas, plasma-excited O2 gas (O2*), O2 gas + hydrogen (H2) gas, water vapor (H2O gas), hydrogen peroxide (H2O2) gas, nitrous oxide (N2O) gas, nitric oxide (NO) gas, nitrogen dioxide (NO2) gas, carbon monoxide (CO) gas, carbon dioxide (CO2) gas, and the like can be used. Note that the juxtaposition of two kinds of gases such as "O2 gas + H2 gas" in this specification means a mixed gas of H2 gas and O2 gas. In the case where a mixed gas is supplied, the two kinds of gases can be mixed (pre-mixed) in a supply pipe before being supplied into the processing chamber 201, or the two kinds of gases can be supplied from different supply pipes into the processing chamber 201 and mixed (post-mixed) in the processing chamber 201. One or more of these gases can be used as the reaction gas. Note that these gases are different in molecular structure (chemical structure), and can be used as the first reaction gas, the second reaction gas, and the third reaction gas described later.

[0152] Further, the present disclosure can also be applied to the case where, by the film formation sequence shown below, a film containing Si such as a silicon oxynitride film (SiON film), a silicon oxycarbide film (SiOC film), a silicon oxycarbide nitride film (SiOCN film), a silicon borocarbide nitride film (SiBCN film), a silicon boron nitride film (SiBN film), a silicon oxide film (SiO film), and the like is formed on a substrate in addition to a SiN film and a SiCN film. The processing steps and the processing conditions at the time of supplying the source gas and the reaction gas can be set to be the same as in each step of the above-described mode, for example. In these cases, the same effects as in the above-described mode can be obtained.

[0153] [(raw material gas → purge) x m → reaction gas → purge] x n

[0154] [(raw material gas → purge) x m → 1st reaction gas → purge → 2nd reaction gas → purge] x n

[0155] [(raw material gas → purge) x m → 1st reaction gas → purge → 2nd reaction gas → purge → 3rd reaction gas → purge] x n

[0156] In addition, for example, the present disclosure can be applied to a case where, as the raw material gas, a raw material gas containing a metal element such as aluminum (Al), titanium (Ti), hafnium (Hf), zirconium (Zr), tantalum (Ta), molybdenum (Mo), tungsten (W), or the like is used, and a film containing a metal element such as an aluminum nitride film (AlN film), a titanium nitride film (TiN film), a hafnium nitride film (HfN film), a zirconium nitride film (ZrN film), a tantalum nitride film (TaN film), a molybdenum nitride film (MoN), a tungsten nitride film (WN), an aluminum oxide film (AlO film), a titanium oxide film (TiO film), a hafnium oxide film (HfO film), a zirconium oxide film (ZrO film), a tantalum oxide film (TaO film), a molybdenum oxide film (MoO), a tungsten oxide film (WO), a titanium oxynitride film (TiON film), a titanium aluminum carbonitride film (TiAlCN film), a titanium aluminum carbide film (TiAlC film), a titanium carbonitride film (TiCN film), or the like is formed on a substrate by the above-described film formation sequence. Note that these raw material gases are gases that differ in molecular structure (chemical structure) from each other, and in addition to functioning as the above-described raw material gas, sometimes function as the above-described 1st reaction gas, 2nd reaction gas, 3rd reaction gas. The processing steps and processing conditions at the time of supplying the raw material gas and the reaction gas can be set to be the same as in each step of the above-described mode. In these cases, the same effects as in the above-described mode can be obtained.

[0157] The recipes used in each process are preferably prepared separately in accordance with the process content and stored in advance in the storage device 121c via an electric communication line or an external storage device 123. Also, preferably, at the start of each process, the CPU 121a appropriately selects a suitable recipe from among the plurality of recipes stored in the storage device 121c in accordance with the process content. Thus, various kinds of films, composition ratios, film qualities, and film thicknesses can be formed with good reproducibility in one substrate processing apparatus. In addition, the burden on the operator can be reduced, and the operator can be prevented from making an operation mistake and can quickly start each process.

[0158] The above process is not limited to a case of creation anew, and for example, can also be prepared by changing an existing process that has been installed in the substrate processing apparatus. In the case of changing the process, the changed process can be installed in the substrate processing apparatus via an electric communication line, a recording medium on which the corresponding process is recorded. Alternatively, the input / output device 122 provided in the existing substrate processing apparatus can be operated to directly change the existing process that has been installed in the substrate processing apparatus.

[0159] In the above-described manner, an example in which a film is formed using a batch-type substrate processing apparatus that processes a plurality of substrates at a time is described. The present disclosure is not limited to the above-described manner, and for example, can also be appropriately applied to a case in which a film is formed using a single-wafer-type substrate processing apparatus that processes one or a few substrates at a time. In the above-described manner, an example in which a film is formed using a substrate processing apparatus having a heat-wall-type processing furnace is described. The present disclosure is not limited to the above-described manner, and can also be appropriately applied to a case in which a film is formed using a substrate processing apparatus having a cold-wall-type processing furnace.

[0160] In a case in which the above-described substrate processing apparatus is used, each processing can also be performed using the same processing steps and processing conditions as those in the above-described manner and modified example, and the same effects as those of the above-described manner and modified example can be obtained.

[0161] The above-described manner and modified example can be used in combination as appropriate. At this time, the processing steps and processing conditions can be set to be the same as those in the above-described manner and modified example, for example.

[0162] Embodiment

[0163] As an embodiment, using the above-described substrate processing apparatus, by Figure 4 A first evaluation sample was produced in which a SiN film was formed as a film on a wafer on which a recessed portion was provided on a surface, using the film formation sequence shown in FIG. 6. In production of the first evaluation sample, an HCDS gas was used as a source gas, and an NH3 gas was used as a reaction gas. The processing conditions were set to be prescribed conditions within the range of the processing conditions described in the above-described manner.

[0164] As a comparative example, using the substrate processing apparatus described above, the cycle in which the step of supplying the HCDS gas and the step of supplying the NH3gas are not performed at the same time was executed a plurality of times, whereby on the wafer on which the recessed portion was provided on the surface, the SiN film was formed as a film, and the second evaluation sample was produced. At the time of production of the second evaluation sample, in the step of supplying the HCDS gas, the HCDS gas supply duration time of each cycle was set to the same time as the total time of the HCDS gas supply duration time of each cycle in the example. The other processing conditions were set to be the same as the processing conditions in the step of supplying the HCDS gas a second time in the step of supplying the HCDS gas a plurality of times in the example described above. The other processing conditions including the processing conditions in the step of supplying the NH3gas were set to be the same as the processing conditions in the example.

[0165] Then, the step coverage of the SiN film in the recessed portion of the first evaluation sample of the example and the step coverage of the SiN film in the recessed portion of the second evaluation sample of the comparative example were measured, respectively. As a result, the step coverage of the SiN film in the second evaluation sample of the comparative example was less than 90%, and, in contrast to this, the step coverage of the SiN film in the first evaluation sample of the example was 90% or more, and it was confirmed that it exceeded the step coverage of the SiN film in the second evaluation sample of the comparative example.

[0166] Explanation of Reference Numerals

[0167] 200 wafer (substrate)

Claims

1. A substrate processing method having a step of forming a film on a substrate by performing a cycle of (a) a step of supplying a raw material gas to a substrate provided with a recess on a surface, and (b) a step of supplying a reaction gas to the substrate, a prescribed number of times. In (a), the raw material gas is supplied to the substrate in multiple stages, and the processing conditions at the time of initial supply of the raw material gas are set to be processing conditions under which the self-decomposition of the raw material gas is suppressed as compared to the processing conditions at the time of supply of the raw material gas after the second time. wherein In (a), the supply flow rate of the raw material gas at the time of initial supply of the raw material gas is made smaller than the supply flow rate of the raw material gas at the time of supply of the raw material gas after the second time.

2. The substrate processing method as recited in claim 1, wherein, In (a), the processing conditions at the time of initial supply of the raw material gas are set to be processing conditions under which the generation of intermediates of the raw material gas is suppressed as compared to the processing conditions at the time of supply of the raw material gas after the second time.

3. The substrate processing method as recited in claim 1, wherein, In (a), the processing conditions at the time of initial supply of the raw material gas are set to be processing conditions under which the self-decomposition of the raw material gas is suppressed, and the processing conditions at the time of supply of the raw material gas after the second time are set to be processing conditions under which the raw material gas self-decomposes.

4. The substrate processing method as recited in claim 1, wherein, In (a), the processing conditions at the time of initial supply of the raw material gas are set to be processing conditions under which the generation of intermediates of the raw material gas is suppressed, and the processing conditions at the time of supply of the raw material gas after the second time are set to be processing conditions under which intermediates of the raw material gas are generated.

5. The substrate processing method as recited in claim 1, wherein, In (a), the supply duration of the raw material gas at the time of initial supply of the raw material gas is made shorter than the supply duration of the raw material gas at the time of supply of the raw material gas after the second time.

6. The substrate processing method as recited in claim 1, wherein, In (a), a carrier gas is also supplied, and the supply flow rate of the carrier gas at the time of initial supply of the raw material gas is made larger than the supply flow rate of the carrier gas at the time of supply of the raw material gas after the second time.

7. The substrate processing method as recited in claim 1, wherein, In (a), the partial pressure of the raw material gas at the time of initial supply of the raw material gas is made lower than the partial pressure of the raw material gas at the time of supply of the raw material gas after the second time.

8. The substrate processing method as recited in claim 1, wherein, In (a), the pressure of the space in which the substrate is present at the time of initial supply of the raw material gas is made lower than the pressure of the space in which the substrate is present at the time of supply of the raw material gas after the second time.

9. The substrate processing method as recited in claim 1, wherein, In (a), the step of supplying the raw material gas to the substrate and the step of purging the space in which the substrate is present are alternately repeated a plurality of times.

10. The substrate processing method as recited in claim 9, wherein, In (a), the time of the step of purging the space in which the substrate is present after the step of initial supply of the raw material gas is made shorter than the time of the step of purging the space in which the substrate is present after the step of final supply of the raw material gas.

11. The substrate processing method as recited in claim 9, wherein, In (a), the time of the step of purging the space in which the substrate is present after the step of second supply of the raw material gas is made shorter than the time of the step of purging the space in which the substrate is present after the step of final supply of the raw material gas.

12. The substrate processing method as recited in claim 9, wherein, In (a), the time of the process of purging the space in which the substrate is present after the process of supplying the raw material gas last time is longest.

13. The substrate processing method as set forth in claim 1, wherein, The raw material gas contains a halosilane gas.

14. The substrate processing method as set forth in claim 1, wherein, The raw material gas contains a chlorosilane gas.

15. The substrate processing method as set forth in claim 1, wherein, In the process of forming a film on the substrate, the cycle of (a) and (b) is performed a prescribed number of times in a manner to obtain a step coverage of 80% or more.

16. The substrate processing method as set forth in claim 1, wherein, In the process of forming a film on the substrate, the cycle of (a) and (b) is performed a prescribed number of times in a manner to obtain a step coverage of 85% or more.

17. The substrate processing method as set forth in claim 1, wherein, In the process of forming a film on the substrate, the cycle of (a) and (b) is performed a prescribed number of times in a manner to obtain a step coverage of 90% or more.

18. A method of manufacturing a semiconductor device, comprising a process of forming a film on a substrate by performing a cycle of (a) a process of supplying a raw material gas to the substrate provided with a recess on a surface, and (b) a process of supplying a reaction gas to the substrate, a prescribed number of times, In (a), the raw material gas is supplied to the substrate in multiple stages, and the processing conditions at the time of initially supplying the raw material gas are set to be processing conditions capable of inhibiting self-decomposition of the raw material gas as compared with the processing conditions at the time of supplying the raw material gas for the second time or more, wherein, In (a), the supply flow rate of the raw material gas at the time of initially supplying the raw material gas is made smaller than the supply flow rate of the raw material gas at the time of supplying the raw material gas for the second time or more.

19. A substrate processing apparatus, comprising: a raw material gas supply system that supplies a raw material gas to a substrate; a reaction gas supply system that supplies a reaction gas to the substrate; a heater that heats the substrate; and a control unit configured to control the raw material gas supply system, the reaction gas supply system, and the heater in such a manner as to perform a process of forming a film on a substrate having a recess on a surface, the process including (a) a process of supplying the raw material gas to the substrate and (b) a process of supplying a reaction gas to the substrate, wherein In (a), the raw material gas is supplied to the substrate in multiple stages, and the processing conditions at the time of initially supplying the raw material gas are set to be processing conditions capable of inhibiting self-decomposition of the raw material gas as compared with the processing conditions at the time of supplying the raw material gas for the second time or more, and, in (a), the supply flow rate of the raw material gas at the time of initially supplying the raw material gas is made smaller than the supply flow rate of the raw material gas at the time of supplying the raw material gas for the second time or more.

20. A recording medium readable by a computer, which records a program for causing a substrate processing apparatus to execute the following steps by using the computer: a process of forming a film on a substrate by performing a cycle of (a) a process of supplying a raw material gas to the substrate provided with a recess on a surface, and (b) a process of supplying a reaction gas to the substrate, a prescribed number of times; in (a), the raw material gas is supplied to the substrate in multiple stages, and the processing conditions at the time of initially supplying the raw material gas are set to be processing conditions capable of inhibiting self-decomposition of the raw material gas as compared with the processing conditions at the time of supplying the raw material gas for the second time or more; and in (a), the supply flow rate of the raw material gas at the time of initially supplying the raw material gas is made smaller than the supply flow rate of the raw material gas at the time of supplying the raw material gas for the second time or more.

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