Substrate processing method, semiconductor device manufacturing method, program, and substrate processing apparatus.

Abstract

To provide a technique for enabling a film formed on a substrate to be improved in properties.SOLUTION: The method of processing a substrate includes: (a) performing a predetermined number of cycles, each cycle including a step of supplying a source containing a predetermined element, carbon and hydrogen to the substrate and a step of supplying a first modifying agent containing nitrogen to the substrate, thereby forming on the substrate a first film containing the predetermined element, nitrogen, carbon, and hydrogen bonded to carbon; and (b) supplying, to the substrate on which the first film is formed, a second modifying agent that is different from the first modifying agent and is a compound comprising a nitrogen-hydrogen bond and a nitrogen-nitrogen bond per molecule or a derivative thereof, thereby modifying the first film into a second film that is lower in the content rate of the hydrogen bonded to carbon than the first film and contains the predetermined element, carbon and nitrogen.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] As one step in the manufacturing process of a semiconductor device, a process may be performed in which a plurality of types of processing gases are supplied to a substrate to form a carbonitride film on the substrate (see, for example, Patent Document 1).

Prior Art Document

Patent Document

[0007] According to this disclosure, it is possible to improve the properties of the film formed on the substrate. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram of a vertical processing furnace of a substrate processing apparatus preferably used in one embodiment of the present disclosure, and shows the processing furnace portion in a vertical cross-sectional view. [Figure 2] Figure 2 is a schematic diagram of a vertical processing furnace of a substrate processing apparatus preferably used in one embodiment of the present disclosure, and shows the processing furnace portion as a cross-sectional view along line AA in Figure 1. [Figure 3] Figure 3 is a schematic configuration diagram of a controller of a substrate processing apparatus preferably used in one embodiment of the present disclosure, and is a block diagram showing the control system of the controller. [Figure 4] Figure 4 is a flowchart showing a substrate processing process preferably used in one embodiment of the present disclosure. [Figure 5] Figure 5(A) is a diagram illustrating the surface state of a substrate when a first modifier is supplied to a substrate on which raw materials have been adsorbed. Figure 5(B) is a diagram illustrating the surface state of a substrate when a second modifier is supplied to a substrate on which raw materials have been adsorbed. [Figure 6] Figure 6 is a flowchart showing a modified example of a substrate processing step preferably used in one embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] <One aspect of this disclosure> Hereinafter, one aspect of this disclosure will be described, mainly with reference to Figures 1 to 5. Note that the drawings used in the following description are all schematic, and the dimensional relationships and ratios of the elements shown in the drawings do not necessarily correspond to reality. Furthermore, the dimensional relationships and ratios of the elements do not necessarily correspond between multiple drawings.

[0010] (1) Configuration of substrate processing apparatus As shown in Figure 1, the processing furnace 202 has a heater 207 as a heating mechanism (temperature control unit). The heater 207 is cylindrical and is mounted vertically by being supported by a holding plate. The heater 207 also functions as an activation mechanism (excitation unit) that activates (excites) the gas with heat.

[0011] 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 a closed upper end and an open lower end. A processing chamber 201 is formed in the hollow part of the reaction tube 203. The processing chamber 201 is configured to accommodate a wafer 200 as a substrate. Processing of the wafer 200 is performed in this processing chamber 201.

[0012] Inside the processing chamber 201, nozzles 249a and 249b are installed so as to penetrate the lower side wall of the reaction tube 203. Gas supply pipes 232a and 232b are connected to nozzles 249a and 249b, respectively.

[0013] In the gas supply pipes 232a and 232b, a mass flow controller (MFC) 241a and 241b, which are flow rate controllers (flow rate control units), and valves 243a and 243b, which are on-off valves, are provided in order from the upstream side of the gas flow. A gas supply pipe 232c is connected to the downstream side of the valve 243a in the gas supply pipe 232a. Gas supply pipes 232d and 232e are respectively connected to the downstream side of the valve 243b in the gas supply pipe 232b. In the gas supply pipes 232c, 232d, and 232e, MFCs 241c, 241d, and 241e and valves 243c, 243d, and 243e are respectively provided in order from the upstream side of the gas flow.

[0014] As shown in FIG. 2, the nozzles 249a and 249b are respectively provided so as to rise upward in the arrangement direction of the wafers 200 along the upper part from the lower part of the inner wall of the reaction tube 203 in an annular space in a plan view between the inner wall of the reaction tube 203 and the wafers 200. That is, the nozzles 249a and 249b are respectively provided along the wafer arrangement region on the side of the wafer arrangement region where the wafers 200 are arranged, in a region that horizontally surrounds 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 are respectively opened so as to face the center of the reaction tube 203, and it is possible to supply gas toward the wafers 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.

[0015] A raw material gas, which is a raw material containing a predetermined element, carbon (C), and hydrogen (H), is configured to be supplied into the processing chamber 201 from the gas supply pipe 232a via the MFC 241a, the valve 243a, and the nozzle 249a.

[0016] In this specification, the raw material gas refers to gaseous raw materials, for example, gases obtained by vaporizing raw materials that are in a liquid state under normal temperature and pressure, or raw materials that are in a gaseous state under normal temperature and pressure, etc. When the term "raw material" is used in this specification, it may mean "liquid raw materials in a liquid state", "raw material gas in a gaseous state", or both.

[0017] From the gas supply pipe 232b, a first reforming agent containing nitrogen (N) is configured to be supplied into the processing chamber 201 via the MFC241b, the valve 243b, and the nozzle 249b. The first reforming agent can also be referred to as the first reforming gas and the first nitriding agent.

[0018] The term "agent" used in this specification includes at least one of gaseous substances and liquid substances. The liquid substance includes mist substances. That is, the film-forming agent, the reforming agent, and the etching agent may contain gaseous substances, may contain liquid substances such as mist substances, or may contain both of them.

[0019] Inert gases are supplied into the processing chamber 201 from the gas supply pipes 232c and 232d via the MFC241c and 241d, the valves 243c and 243d, the gas supply pipes 232a and 232b, and the nozzles 249a and 249b, respectively. The inert gas acts as a purge gas, a carrier gas, a dilution gas, etc.

[0020] From the gas supply pipe 232e, a second reforming agent that is different from the first reforming agent and has a higher reactivity than the first reforming agent is supplied into the processing chamber 201 via the MFC241e, the valve 243e, the gas supply pipe 232b, and the nozzle 249b. The second reforming agent can also be referred to as the second reforming gas and the second nitriding agent.

[0021] The raw material gas supply system (raw material supply system) mainly consists of gas supply pipes 232a, MFC 241a, and valve 243a, which supply the raw material gas. The first reformer supply system (first reformed gas supply system, first nitrider supply system) mainly consists of gas supply pipes 232b, MFC 241b, and valve 243b, which supply the first reformer. The inert gas supply system mainly consists of gas supply pipes 232c, 232d, MFC 241c, 241d, and valves 243c, 243d, which supply the inert gas. The second reformer supply system (second reformed gas supply system, second nitrider supply system) mainly consists of gas supply pipes 232e, MFC 241e, and valve 243e, which supply the second reformer.

[0022] Of the various supply systems described above, one or all of them may be configured as an integrated supply system 248, which is comprised of valves 243a to 243e and MFCs 241a to 241e, etc. The integrated supply system 248 is connected to each of the gas supply pipes 232a to 232e, and the supply operation of various gases into the gas supply pipes 232a to 232e, i.e., the opening and closing operation of valves 243a to 243e and the flow rate adjustment operation by MFCs 241a to 241e, etc., is controlled by a controller 121, which will be described later. The integrated supply system 248 is configured as an integrated or segmented integrated unit, and can be attached to and detached from the gas supply pipes 232a to 232e, etc., in units of the integrated unit, and is configured so that maintenance, replacement, and expansion of the integrated supply system 248 can be performed in units of the integrated unit.

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

[0024] Below the reaction tube 203, a seal cap 219 is provided as a furnace opening cover capable of airtightly closing the lower end opening of the reaction tube 203. The seal cap 219 is made of a metal material such as SUS and is formed in a disc shape. An O-ring 220 is provided on the upper surface of the seal cap 219 as a sealing member that contacts the lower end of the reaction tube 203. Below the seal cap 219, a rotating mechanism 267 for rotating the boat 217, which will be described later, is installed. The rotation shaft 255 of the rotating mechanism 267 passes through the seal cap 219 and is connected to the boat 217. The rotating mechanism 267 is configured to rotate the wafer 200 by rotating the boat 217. The seal cap 219 is configured to be raised and lowered vertically by a boat elevator 115, which is installed outside the reaction tube 203 as a lifting mechanism. The boat elevator 115 is configured as a transport device (transport mechanism) that moves the wafer 200 into and out of the processing chamber 201 by raising and lowering the seal cap 219.

[0025] The boat 217, which serves as a substrate support, is configured to support multiple wafers 200, for example 25 to 200 wafers 200, in a horizontal position and aligned vertically with their centers aligned, in a multi-stage arrangement, that is, arranged with spacing between them. The boat 217 is made of a heat-resistant material such as quartz or SiC. Below the boat 217, a heat-insulating plate 218, also made of a heat-resistant material such as quartz or SiC, is supported in a multi-stage horizontal position.

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

[0027] As shown in Figure 3, the controller 121, which is the control unit (control means), is configured as a computer equipped with a CPU (Central Processing Unit) 121a, RAM (Random Access Memory) 121b, storage device 121c, and 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, configured as, for example, a touch panel, is connected to the controller 121. An external storage device 123 can also be connected to the controller 121. The board processing device may be configured to have one control unit, or it may be configured to have multiple control units. That is, the control for performing the processing sequence described later may be performed using one control unit, or it may be performed using multiple control units. Furthermore, the multiple control units may be configured as a control system connected to each other by a wired or wireless communication network, and the control for performing the processing sequence described later may be performed by the entire control system. In this specification, the term "control unit" may refer to a single control unit, a plurality of control units, or a control system composed of a plurality of control units.

[0028] The storage device 121c is composed of, for example, flash memory, an HDD (Hard Disk Drive), etc. The storage device 121c contains, in a readable format, control programs that control the operation of the substrate processing device, and process recipes that describe the procedures and conditions of the substrate processing process, which will be described later. The process recipe is a combination of steps in the substrate processing process, described later, that cause the controller 121 to execute and obtain predetermined results; it functions as a program. Hereinafter, process recipes and control programs will be collectively referred to simply as "programs." Similarly, process recipes will be referred to simply as "recipes." In this specification, the term "program" may include only recipes, only control programs, or both. The RAM 121b is configured as a memory area (work area) where programs and data read by the CPU 121a are temporarily held.

[0029] I / O port 121d is connected to the MFCs 241a to 241e, valves 243a to 243e, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotary mechanism 267, boat elevator 115, etc.

[0030] The CPU 121a is configured to read and execute a control program from the storage device 121c, and to read a recipe from the storage device 121c in response to input of operation commands from the input / output device 122. The CPU 121a is configured to control the flow rate adjustment operation of various gases by the MFCs 241a to 241e, the opening and closing operation of valves 243a to 243e, the opening and closing operation of the APC valve 244 and the pressure adjustment operation of the APC valve 244 based on the pressure sensor 245, the starting and stopping of the vacuum pump 246, the temperature adjustment operation of the heater 207 based on the temperature sensor 263, the rotation and rotation speed adjustment operation of the boat 217 by the rotating mechanism 267, and the raising and lowering operation of the boat 217 by the boat elevator 115, in accordance with the contents of the read recipe.

[0031] The controller 121 can be configured by installing the above-mentioned program stored in the external storage device 123 onto a computer. The external storage device 123 includes, for example, magnetic disks such as HDDs, optical disks such as CDs, magneto-optical disks such as MOs, and semiconductor memory such as USB memory. The storage device 121c and the external storage device 123 are configured as computer-readable recording media on which the program is recorded. Hereinafter, these will be collectively referred to simply as recording media. In this specification, the term recording media may include only the storage device 121c, only the external storage device 123, or both. Note that the program may be provided to the computer using communication means such as the Internet or a dedicated line, without using the external storage device 123.

[0032] (2) Substrate processing process Using the processing furnace 202 of the substrate processing apparatus described above, an example of performing a semiconductor device manufacturing process that includes the steps of forming a first film containing predetermined elements, N, C, and C-bonded H on a wafer 200 on which a silicon film (Si film) has been formed on its surface, and modifying the first film into a second film containing predetermined elements, C, and N, with a reduced content ratio of C-bonded H compared to the first film, will be explained mainly with reference to Figures 4 and 5. In the following explanation, the operation of each part constituting the substrate processing apparatus is configured to be controllable by the controller 121.

[0033] In this specification, the term "wafer" may refer to the wafer itself or to a laminate of a wafer and a predetermined layer or film formed on its surface. In this specification, the term "surface of the wafer" may refer to the surface of the wafer itself or to the surface of a predetermined layer formed on the wafer. In this specification, when it is stated that "a predetermined layer is formed on the wafer," it may mean that the predetermined layer is formed directly on the surface of the wafer itself or that the predetermined layer is formed on a layer already formed on the wafer. In this specification, the term "substrate" has the same meaning as when it is used with the term "wafer."

[0034] [First film formation process (also called film deposition process)] (Wafer charge and boat load, step S11) Multiple wafers 200 are loaded into the boat 217 (wafer charging). Then, as shown in Figure 1, the boat 217 supporting the multiple wafers 200 is lifted by the boat elevator 115 and moved into the processing chamber 201 (boat loading). In this state, the seal cap 219 seals the lower end of the reaction tube 203 via the O-ring 220.

[0035] (Pressure adjustment and temperature adjustment, step S12) The processing chamber 201 is evacuated (reduced pressure exhausted) by a vacuum pump 246 so that the pressure inside the processing chamber 201, i.e., the pressure in the space where the wafer 200 is located, reaches the desired pressure (vacuum level). At this time, the pressure inside the processing chamber 201 is measured by a pressure sensor 245, and the APC valve 244 is feedback controlled based on this measured pressure information. The vacuum pump 246 is kept running continuously at least until the processing of the wafer 200 is completed. The wafer 200 inside the processing chamber 201 is heated by a heater 207 so that it reaches the desired temperature. At this time, the amount of power supplied to the heater 207 is feedback controlled based on the temperature information detected by the temperature sensor 263 so that the processing chamber 201 has the desired temperature distribution. Heating inside the processing chamber 201 by the heater 207 is continued at least until the processing of the wafer 200 is completed. The boat 217 and the wafer 200 are also rotated by a rotating mechanism 267. The rotation of the boat 217 and the wafer 200 by the rotating mechanism 267 continues at least until the processing of the wafer 200 is completed.

[0036] (Pre-flow gas supply, step S13) First, a pre-flow gas is supplied to the wafer 200 in the processing chamber 201. As the pre-flow gas, a first modifier gas containing nitrogen can be used. Details of the first modifier will be described later. This step is performed as a pre-flow to facilitate the adsorption of the raw material gas onto the surface of the wafer 200 in step S15, which will be described later. Specifically, valve 243b is opened and the first modifier is flowed into the gas supply pipe 232b. The flow rate of the first modifier is adjusted by MFC 241b and supplied into the processing chamber 201 via nozzle 249b and exhausted from exhaust pipe 231. At the same time, valve 243d is opened and an inert gas is flowed into the gas supply pipe 232d. The flow rate of the inert gas is adjusted by MFC 241d and supplied into the processing chamber 201 together with the first modifier and exhausted from exhaust pipe 231.

[0037] Furthermore, to prevent the first reforming agent from entering the nozzle 249a, valve 243c is opened and inert gas is flowed into the gas supply pipe 232c. The inert gas is supplied into the processing chamber 201 via the gas supply pipe 232a and nozzle 249a, and exhausted from the exhaust pipe 231.

[0038] By supplying a gas containing, for example, a hydrogen nitride-based compound as a preflow gas to the wafer 200, the native oxide layer on the wafer 200 is nitrided, forming NH terminations on the wafer 200. This increases the density of NH terminations on the wafer 200 surface, which serve as adsorption sites for raw materials, forming a uniform adsorption surface and improving the film deposition rate. Preferred examples of preflow gases used in this step will be described later.

[0039] In addition to nitrogen (N2) gas, noble gases such as argon (Ar), helium (He), neon (Ne), and xenon (Xe) gas can be used as inert gases. One or more of these can be used as the inert gas.

[0040] (Removal of residual gas, step S14) Next, residual gas in the processing chamber 201 is removed. Specifically, after NH terminations are formed on the surface of the wafer 200, valve 243b is closed to stop the supply of the first modifier. At this time, APC valve 244 is left open, and the processing chamber 201 is evacuated using vacuum pump 246 to remove any unreacted or by-products of the first modifier that have contributed to the formation of NH terminations from the processing chamber 201. At this time, valves 243c and 243d are left open to maintain the supply of inert gas to the processing chamber 201. The inert gas acts as a purge gas.

[0041] Then, the next steps S15 to S19 are executed sequentially.

[0042] (Raw material gas supply, step S15) In this step, the raw material gas is supplied into the processing chamber 201. Specifically, with the APC valve 244 open to a predetermined degree, valve 243a is opened and the raw material gas flows into the gas supply pipe 232a. The flow rate of the raw material gas is regulated by the MFC 241a and supplied into the processing chamber 201 from the gas supply hole 250a, and exhausted from the exhaust pipe 231. At this time, the raw material gas is supplied to the wafer 200. Simultaneously, with valve 243c left open, inert gas is supplied into the gas supply pipe 232c. The flow rate of the inert gas is regulated by the MFC 241c and supplied into the processing chamber 201 together with the raw material gas, and exhausted from the exhaust pipe 231.

[0043] Furthermore, to prevent raw material gas from entering the nozzle 249b, the valve 243d is kept open and inert gas is flowed into the gas supply pipe 232d. The inert gas is supplied into the processing chamber 201 via the gas supply pipe 232b and nozzle 249b, and exhausted through the exhaust pipe 231.

[0044] The processing conditions when supplying the raw material gas in this step are as follows: Processing temperature: 150-800°C, preferably 180-700°C, more preferably 400-700°C Processing pressure: 1 to 2666 Pa, preferably 67 to 1333 Pa Raw material gas supply flow rate: 1 to 2000 sccm, preferably 10 to 1000 sccm Raw material gas supply time: 1 to 120 seconds, preferably 1 to 60 seconds Inert gas supply flow rate: 100~10000 sccm Examples include the following. Furthermore, from the viewpoint of improving processing speed, it is particularly preferable to keep the processing temperature substantially the same at every step of the first film formation process.

[0045] In this disclosure, numerical ranges such as "150~800℃" mean that the lower and upper limits are included within that range. For example, "150~800℃" means "150℃ or more and 800℃ or less." The same applies to other numerical ranges. In this disclosure, processing temperature means the temperature of the wafer 200 or the temperature inside the processing chamber 201, and processing pressure means the pressure inside the processing chamber 201. Processing time means the time during which the processing is continued. These terms are also used in the following explanation.

[0046] If the temperature of wafer 200 falls below 150°C, the raw materials become less likely to chemically adsorb onto the wafer 200, and a practical film deposition rate may not be obtainable. This can be resolved by raising the temperature of wafer 200 to 150°C or higher. Raising the temperature of wafer 200 to 180°C or higher allows for sufficient adsorption of the raw materials onto the wafer 200, resulting in a sufficient film deposition rate. Raising the temperature of wafer 200 to 400°C or higher allows for even more sufficient adsorption of the raw materials onto the wafer 200, resulting in an even more sufficient film deposition rate.

[0047] When the temperature of wafer 200 exceeds 800°C, the CVD reaction becomes stronger (gas-phase reaction becomes dominant), which tends to worsen film thickness uniformity and makes it difficult to control. By keeping the temperature of wafer 200 below 800°C, the deterioration of film thickness uniformity can be suppressed and controlled. By keeping the temperature of wafer 200 below 700°C, surface reactions become dominant, making it easier to ensure film thickness uniformity and to control it.

[0048] In other words, by setting the temperature of the wafer 200 in this process to, for example, 150 to 800°C, the raw material can be adsorbed onto the wafer 200, improving the film deposition rate while also improving the uniformity of the film thickness. Furthermore, excessive gas-phase reactions can be suppressed, thereby reducing the generation of particles.

[0049] By supplying a raw material gas to the wafer 200, a first layer is formed on the wafer 200, which has NH terminations formed on its surface. This first layer contains predetermined elements, C, and H, and has a thickness ranging from less than one atomic layer to several atomic layers. That is, when a gas containing Si, C, and H as predetermined elements is used as the raw material gas, the first layer contains H derived from the raw material in addition to Si-C bonds. The H in the first layer constitutes bonds such as CH bonds and Si-H bonds. The Si-containing layer containing C and H becomes a layer containing Si-C bonds, Si-H bonds, and CH bonds. The Si-containing layer containing C and H may be a Si layer containing C and H, an adsorption layer of the raw material gas, or both.

[0050] The term "Si layer containing C and H" is a general term that includes not only continuous Si layers containing C and H, but also discontinuous Si layers and Si thin films containing C and H formed by the overlapping of these layers. Sometimes, a continuous Si layer containing C and H is simply referred to as a Si thin film containing C and H. The Si particles constituting the Si layer containing C and H include those whose bonds with C and H are not completely broken, as well as those whose bonds with C and H are completely broken.

[0051] The adsorption layer of the raw material gas includes not only a continuous adsorption layer of raw material gas molecules but also discontinuous adsorption layers. In other words, the adsorption layer of the raw material gas includes an adsorption layer with a thickness of one molecular layer or less than one molecular layer, composed of the molecules that make up the raw material gas.

[0052] Here, a layer with a thickness of less than one atomic layer refers to an atomic layer that is formed discontinuously, while a layer with a thickness of one atomic layer refers to an atomic layer that is formed continuously. A layer with a thickness of less than one molecular layer refers to a molecular layer that is formed discontinuously, while a layer with a thickness of one molecular layer refers to a molecular layer that is formed continuously.

[0053] Under conditions where the source gas self-decomposes (e.g., through thermal decomposition), a Si layer containing C and H is formed on the wafer 200 by the deposition of, for example, Si. Under conditions where the source gas does not self-decompose, an adsorption layer of the source gas is formed on the wafer 200 by the adsorption of the source gas. Under both conditions, at least some of the bonds in the source gas, such as Si-C bonds, Si-H bonds, and CH bonds, are retained (maintained) without being broken and are incorporated into the Si-containing layer containing C and H.

[0054] As the raw material gas, a gas containing a specified element, C, and H can be used. As a gas containing a specified element, C, and H, for example, a gas containing Si, C, and H as the specified element can be used. As a gas containing Si, C, and H, for example, a gas containing hydrocarbon groups, i.e., compounds containing CH bonds, such as alkylsilane gas or alkylenesilane gas can be used.

[0055] Furthermore, as the gas containing the specified element, C, and H, a gas containing the specified element, C, H, and halogen elements can be used. As the gas containing the specified element, C, H, and halogen elements, for example, a gas containing Si, C, H as the specified element, and chlorine (Cl) as the halogen element can be used. As the gas containing Si, C, H, and Cl, for example, an alkylene halosilane gas containing Si, an alkylene group, and a halogen group, having a chemical bond between Si and C (Si-C bond), or an alkyl halosilane gas containing Si, an alkyl group, and a halogen group, having a Si-C bond can be used.

[0056] Here, an alkylene group is defined as having the general formula C n H 2n+2 It is a functional group obtained by removing two hydrogen atoms from a chain-like saturated hydrocarbon (alkane) represented by the general formula C n H 2n It is an aggregate of atoms represented by the formula C. Alkylene groups include methylene, ethylene, propylene, and butylene groups. Furthermore, alkyl groups are generally defined by the formula C. n H 2n+2A functional group obtained by removing one H from a chain-like saturated hydrocarbon represented by the general formula C n H 2n+1 It is an aggregate of atoms represented by . Alkyl groups include methyl, ethyl, propyl, and butyl groups. Halogen groups include chloro, fluoro, and bromo groups. In other words, halogen groups include halogen elements such as chlorine (Cl), fluorine (F), and bromine (Br).

[0057] As the alkylene halosilane gas, for example, a gas containing Si, a methylene group (-CH2-) as an alkylene group, and a chloro group (Cl) as a halogen group, i.e., a chlorosilane gas containing a methylene group, or a gas containing Si, an ethylene group (-C2H4-) as an alkylene group, and a chloro group (Cl) as a halogen group, i.e., a chlorosilane gas containing an ethylene group can be used. As the chlorosilane gas containing a methylene group, for example, methylenebis(trichlorosilane) gas, i.e., bis(trichlorosilyl)methane ((SiCl3)2CH2, abbreviated as BTCSM) gas can be used. As the chlorosilane gas containing an ethylene group, for example, ethylenebis(trichlorosilane) gas, i.e., 1,2-bis(trichlorosilyl)ethane ((SiCl3)2C2H4, abbreviated as BTCSE) gas can be used.

[0058] As the alkylhalosilane gas, for example, a gas containing Si, a methyl group (-CH3) as an alkyl group, and a chloro group (Cl) as a halogen group, that is, a chlorosilane gas containing a methyl group can be used. As a chlorosilane gas containing a methyl group, for example, 1,1,2,2-tetrachloro-1,2-dimethyldisilane ((CH3)2Si2Cl4, abbreviation: TCDMDS) gas, 1,2-dichloro-1,1,2,2-tetramethyldisilane ((CH3)4Si2Cl2, abbreviation: DCTMDS) gas, 1-monochloro-1,1,2,2,2-pentamethyldisilane ((CH3)5Si2Cl, abbreviation: MCPMDS) gas, etc. can be used. Alkylhalosilane gases such as TCDMDS gas, DCTMDS gas, and MCPMDS gas differ from alkylenehalosilane gases such as BTCSE gas and BTCSM gas in that they are gases containing Si-Si bonds, meaning they contain specific elements and halogen elements, and are also source gases that have chemical bonds between specific elements.

[0059] Alkylene halosilane gases such as BTCSM gas and BTCSE gas, and alkylhalosilane gases such as TCDMDS gas, DCTMDS gas, and MCPMDS gas, can be described as feedstock gases containing at least two Si molecules, further containing Cl, and possessing Si-C bonds and CH bonds. These gases act as both Si sources and C sources in this process. BTCSM gas and BTCSE gas can also be referred to as alkylene chlorosilane gases. TCDMDS gas, DCTMDS gas, and MCPMDS gas can also be referred to as alkylchlorosilane gases.

[0060] When a gas containing a specified element, C, H, and halogen elements is used as the raw material gas, the first layer may contain halogen elements originating from the raw material gas as impurities, in addition to the specified element, C, and H. For example, if Cl is included as a halogen element in the raw material gas, the first layer will also contain bonds such as Si-Cl bonds.

[0061] (Removal of residual gas, step S16) Next, residual gas in the processing chamber 201 is removed. Specifically, after the first layer is formed, valve 243a is closed to stop the supply of raw material gas. At this time, APC valve 244 is left open, and the processing chamber 201 is evacuated using vacuum pump 246 to remove any unreacted raw material gas or by-products that have contributed to the formation of the first layer remaining in the processing chamber 201. At this time, valves 243c and 243d are left open to maintain the supply of inert gas to the processing chamber 201. The inert gas acts as a purge gas.

[0062] (First modifier supply, step S17) Next, the first modifier is supplied to the wafer 200 in the processing chamber 201. Specifically, similar to step S13 described above, valve 243b is opened and the first reformer is flowed into the gas supply pipe 232b. The flow rate of the first reformer is regulated by MFC 241b and supplied into the processing chamber 201 via nozzle 249b, and exhausted through exhaust pipe 231. At the same time, valve 243d is kept open and inert gas is flowed into the gas supply pipe 232d. The flow rate of the inert gas is regulated by MFC 241d and supplied into the processing chamber 201 together with the first reformer, and exhausted through exhaust pipe 231.

[0063] Furthermore, to prevent the first reforming agent from entering the nozzle 249a, the valve 243c is kept open and inert gas is flowed into the gas supply pipe 232c. The inert gas is supplied into the processing chamber 201 via the gas supply pipe 232a and nozzle 249a, and exhausted from the exhaust pipe 231.

[0064] The processing conditions when supplying the first modifier in this step are as follows: Processing pressure: 1 to 4000 Pa, preferably 10 to 1000 Pa First modifier supply flow rate: 0.1 to 20 slm, preferably 1 to 10 slm First modifier supply time: 1 to 120 seconds, preferably 10 to 60 seconds Inert gas supply flow rate: 0-10 slm Examples are given. Other processing conditions can be the same as the processing conditions when supplying the raw material gas in the raw material gas supply step.

[0065] As the first reforming agent, an N-containing gas can be used. Examples of N-containing gases include nitrogen (N2) gas, ammonia (NH3) gas, diazene (N2H2) gas, hydrazine (N2H4) gas, N3H5 gas, and other hydrogen nitride-based gases. One or more of these N-containing gases can be used.

[0066] As will be described later, in this step, it is preferable to use a gas containing a hydrogen nitride-based compound that contains N and does not contain an NN bond (a bond between two N atoms) in a single molecule as the first modifier. Examples of gases containing a hydrogen nitride-based compound that contains N and does not contain an NN bond (a bond between two N atoms) in a single molecule include NH3 gas.

[0067] Furthermore, the first reformer used in the pre-flow gas supply step S13 described above may be different from the first reformer used in this step. For example, in the pre-flow gas supply step, a gas containing a hydrogen nitride-based compound that contains N and an NN bond (a bond between N atoms) in one molecule may be used, while in this step, a gas containing a hydrogen nitride-based compound that contains N and does not contain an NN bond (a bond between N atoms) in one molecule may be used. For example, in the pre-flow gas supply step, the second reformer described later may be supplied as the pre-flow gas.

[0068] By supplying a first modifier containing N to wafer 200, at least a portion of the first layer formed on wafer 200 is nitrided (modified). This modification of the first layer forms a second layer containing, for example, Si-C bonds, Si-N bonds, CN bonds, as well as impurities such as H and Cl remaining in the first layer. The H in the second layer constitutes bonds such as CH bonds, Si-H bonds, and NH bonds. In other words, by using the first modifier, the first layer containing predetermined elements, C, and H is modified into a second layer containing predetermined elements, C, H, and N, forming, for example, a silicon carbonitride layer (SiCN layer).

[0069] Here, while some of the H and Cl in the first layer are removed by supplying the first modifier, H and Cl in concentrations exceeding the desired level remain in the second layer. This retention of impurities such as H and Cl in excess of the desired level in the film can reduce the film density and decrease the ashing resistance.

[0070] Furthermore, in this step, if a gas containing a highly reactive hydrogen nitride compound or its derivative, such as the second modifier described in detail later, is used, excessive carbon may be eliminated from the first layer while the nitriding reaction is progressing until the nitrogen concentration in the first layer reaches the desired concentration. In other words, it may not be possible to maintain the carbon concentration in the second layer at the desired concentration. Therefore, it is preferable to use a gas containing a less reactive hydrogen nitride compound as the first modifier in this step. As a gas containing a less reactive hydrogen nitride compound, a gas containing a hydrogen nitride compound that contains nitrogen and does not contain an NN bond (a bond between nitrogen atoms) in a single molecule can be used.

[0071] Furthermore, supplying the first reforming agent after activating it with heat in a non-plasma state allows the above-mentioned reaction to proceed more gently, facilitating the formation of the second layer. When forming the second layer, impurities such as Cl contained in the first layer form a gaseous substance containing at least Cl during the reforming reaction of the first layer by the first reforming agent, and are discharged from the processing chamber 201. In other words, impurities such as Cl in the first layer are separated from the first layer by being extracted or desorbed. As a result, the second layer contains fewer impurities such as Cl compared to the first layer.

[0072] (Removal of residual gas, step S18) Next, residual gas in the processing chamber 201 is removed. Specifically, after the second layer is formed, valve 243b is closed to stop the supply of the first reformer. At this time, APC valve 244 is left open, and the processing chamber 201 is evacuated using vacuum pump 246 to remove any unreacted or remaining first reformer and by-products that have contributed to the formation of the second layer from the processing chamber 201. At this time, valves 243c and 243d are left open to maintain the supply of inert gas to the processing chamber 201. The inert gas acts as a purge gas.

[0073] (The first predetermined number of times is performed, step S19) The above steps S15 to S18 are performed non-simultaneously for a first predetermined number of times (n times, where n is an integer of 1 or more). This allows a first film containing predetermined elements, N, C, and H bonded to C (i.e., CH bonds) to be formed on the wafer 200. Preferably, the above cycle is performed multiple times until the first film reaches a desired thickness. As the first film, for example, a silicon carbonitride film (SiCN film) containing Si, N, C, and CH bonds can be formed.

[0074] In this case, the thickness of the first film is set to, for example, 10 to 200 Å, preferably 10 to 100 Å. If the thickness of the first film is less than 10 Å, it may not be possible to obtain a film with the desired properties. By setting the thickness of the first film to 10 Å or more, it becomes possible to obtain a film with the desired properties. Furthermore, if the thickness of the first film exceeds 200 Å, the modification effect by the modification process described later may not be sufficiently extended throughout the entire thickness direction of the first film. By setting the thickness of the first film to 200 Å or less, the modification effect by the modification process described later can be extended throughout the entire thickness direction of the first film. By setting the thickness of the first film to 100 Å or less, the modification effect by the modification process described later can be more reliably extended throughout the entire thickness direction of the first film.

[0075] In this configuration, the first film contains Si-C bonds, Si-N bonds, and CN bonds, as well as impurities such as H and Cl remaining from the first layer. The H in the first film constitutes bonds such as CH bonds, Si-H bonds, and NH bonds. When CH bonds, Si-H bonds, and NH bonds remain in the film, the ashing resistance deteriorates. However, if plasma treatment is performed on the first film to remove impurities such as H and Cl in order to improve this ashing resistance, not only H and Cl but also C may be removed from the film. Therefore, in this embodiment, in order to reduce impurities such as H and Cl while suppressing the removal of C from the film, the following modification step is performed after the above-described film formation step.

[0076] In this embodiment, after forming the first film by performing the film formation process (steps S12 to S19) described above, the next modification process (steps S20 to S22) is performed without exposing the wafer 200 to an oxygen-containing atmosphere. If the wafer 200 is exposed to an oxygen-containing atmosphere after the first film has been formed, an oxide layer may form on the surface of the first film. If an oxide layer is formed on the surface of the first film, the modification effect in the depth direction of the first film in step S21, described later, which is the reduction effect of H and the like, may be inhibited, and the modification effect may not be obtained sufficiently. In other words, by performing the next second film formation process without exposing the wafer 200 to an oxygen-containing atmosphere after the first film formation process, the modification effect in step S21 can be improved. That is, the next second film formation process is performed while no oxide layer has been formed on the surface of the first film.

[0077] The second film formation process is performed after the supply of the first modifier in step S17 of the first film formation process, and after the removal of residual gas in step S18, which purges (also called inert gas purging) the space where the wafer 200 is located. In other words, the space where the wafer 200 is located is purged after the film formation process and before the modification process. This allows for the removal of impurities such as Cl to some extent before the modification process.

[0078] [Second film formation process (also called modification process)] (Pressure adjustment and temperature adjustment, step S20) The processing chamber 201 is evacuated by a vacuum pump 246 so that the pressure inside reaches the desired pressure. Additionally, the wafer 200 inside the processing chamber 201 is heated by a heater 207 so that it reaches the desired temperature.

[0079] (Second modifier supply, step S21) Next, the second modifier is supplied to the wafer 200 on which the first film has been formed. Specifically, valve 243e is opened, and the second modifier is allowed to flow into the gas supply pipe 232b. The flow rate of the second modifier is regulated by MFC 241e and supplied into the processing chamber 201 via nozzle 249b, and exhausted through exhaust pipe 231. At the same time, valve 243d is kept open, and inert gas is allowed to flow into the gas supply pipe 232d. The flow rate of the inert gas is regulated by MFC 241d and supplied into the processing chamber 201 together with the second modifier, and exhausted through exhaust pipe 231.

[0080] Furthermore, to prevent the second reforming agent from entering the nozzle 249a, the valve 243c is kept open and inert gas is flowed into the gas supply pipe 232c. The inert gas is supplied into the processing chamber 201 via the gas supply pipe 232a and nozzle 249a, and exhausted from the exhaust pipe 231.

[0081] The processing conditions when supplying the second modifier in this step are as follows: Processing temperature: Room temperature to 700°C, preferably 150 to 700°C, more preferably 150 to 400°C Processing pressure: 1 to 2666 Pa, preferably 67 to 1333 Pa Second modifier supply flow rate: 1 to 2000 sccm, preferably 10 to 1000 sccm Second modifier supply time: 1 to 120 seconds, preferably 1 to 60 seconds Inert gas supply flow rate: 0-10000 sccm Examples include the following. However, from the viewpoint of improving processing speed, it is preferable that the processing temperature in this step be substantially the same as the processing temperature in the first film formation step.

[0082] If the temperature of wafer 200 is below room temperature, the second modifier is hardly activated, and a sufficient modification effect may not be obtained when modifying the first film. By raising the temperature of wafer 200 to room temperature or higher, the second modifier can be activated, and the modification effect can be exerted throughout the entire thickness direction of the first film. Furthermore, by raising the temperature of wafer 200 to 150°C or higher, the activation of the second modifier can be further promoted, and the modification effect can be more reliably exerted throughout the entire thickness direction of the first film.

[0083] If the temperature of wafer 200 exceeds 700°C, the thermal decomposition of the second modifier may proceed excessively, potentially resulting in a loss of the modification effect on the first film. For example, if N2H4 is used as the second modifier, excessive thermal decomposition may lead to the generation of less reactive NH3 instead of the highly reactive intermediate NH2, potentially resulting in a loss of the modification effect on the first film. Similarly, if the temperature of wafer 200 exceeds 400°C, the thermal decomposition of the second modifier may proceed partially, reducing the modification effect on the first film for the same reason. The modification effect can be obtained by keeping the wafer temperature below 700°C. Furthermore, the modification effect can be more reliably obtained by keeping the wafer temperature below 400°C.

[0084] By setting the temperature of the wafer 200 in this process to room temperature to 700°C, the second modifier or its intermediate reacts with H bonded to C, H bonded to Si, Cl bonded to Si, etc. in the first film, making it easy to control the reactivity of the second modifier so as to suppress the desorption of C while desorbing H, Cl, etc.

[0085] Furthermore, by setting the temperature of the wafer 200 in this process lower than the temperature of the wafer 200 in the first film formation process described above, it becomes easier to adjust the degree of thermal decomposition and activation of the second modifier and control the reactivity of the second modifier and / or its intermediates. Therefore, it becomes easier to control the reactivity of the second modifier so as to desorb H bonded to C while suppressing the desorption of C from the first film. In addition, by performing this process at a lower temperature, the influence of thermal history on the wafer 200 that occurs during this process can be reduced. On the other hand, by setting the processing temperature to substantially the same temperature as the processing temperature in the first film formation process, the processing speed for the wafer 200 can be improved.

[0086] At this time, the partial pressure of the second modifier is made smaller than the partial pressure of the first modifier in step S17 described above. Alternatively, the flow rate of the second modifier may be made smaller than the flow rate of the first modifier in step S17 described above. This makes it easier to control the reaction rate of the second modifier, which is more reactive than the first modifier.

[0087] In this case, when the first film is modified using a plasma-excited second modifier, the radicals generated by the plasma excitation have excessively high reactivity, causing not only H bonded to C in the film but also C bonded to predetermined elements and N to be desorbed by these radicals. In this disclosure, a second modifier, which is more reactive than the first modifier, is supplied to the wafer 200 in a non-plasma state. This makes it possible to selectively desorb H bonded to C while suppressing the desorption of C.

[0088] As the second modifier, a gas containing a hydrogen nitride-based compound or a derivative thereof, which contains both an N-H bond (i.e., an NH bond) and an N-N bond (i.e., an NN bond) in one molecule, can be used.

[0089] As a second modifier, for example, a gas containing at least one compound from among diazene (N2H2), hydrazine (N2H4), triazene (N3H3), triazane (N3H5), etc., which are hydrogen nitride compounds containing both NH and NN bonds in one molecule, can be used. Alternatively, as a second modifier, a gas containing derivatives of hydrogen nitride compounds containing both NH and NN bonds in one molecule, such as monomethylhydrazine (CH3(NH)NH2), 1,1-dimethylhydrazine (unsymmetric dimethylhydrazine) ((CH3)2-N-NH2), 1,2-dimethylhydrazine (tetramethylhydrazine) (N2(CH3)4), etc., can be used. One or more of these can be used as the second modifier.

[0090] (Removal of residual gas, step S22) Next, residual gas in the processing chamber 201 is removed. Specifically, after the first membrane is reformed and the second membrane is formed, valve 243e is closed to stop the supply of the second reformer. At this time, APC valve 244 is left open, and the processing chamber 201 is evacuated using vacuum pump 246 to remove any unreacted or partially reformed second reformer and by-products that have contributed to the reforming of the first membrane from the processing chamber 201. At this time, valves 243c and 243d are left open to maintain the supply of inert gas to the processing chamber 201. The inert gas acts as a purge gas.

[0091] By supplying the second modifier to the wafer 200 in a non-plasma manner, at least a portion of the first film formed on the wafer 200 is nitrided (modified) and densified. This modification of the first film results in the formation of a second film on the wafer 200, for example, a SiCN film containing Si, C, and N. Activating the second modifier by heat in a non-plasma manner allows the above reaction to proceed more smoothly, facilitating the formation of the second film. During the formation of the second film, impurities such as H and Cl contained in the first film form a gaseous substance containing at least H and Cl in this process and are discharged from the processing chamber 201. In other words, the first film is modified using a second modifier that is more reactive to CH bonds, Si-H bonds, NH bonds, etc., in the first film compared to the first modifier. This causes the intermediate of the second modifier to react with H and Cl in the CH bonds, Si-H bonds, NH bonds, etc., in the first film, thereby removing H and Cl from the first film. In other words, impurities such as H and Cl are removed while maintaining the C concentration in the first film within a desired range. To put it another way, the first film on the wafer 200 can be modified into a second film containing a predetermined element, C, and N, in which the proportion of H bonded to C is reduced compared to the first film.

[0092] By reducing impurities such as H and Cl in the film in this way, the ashing resistance of the film can be improved. Furthermore, by maintaining the C concentration in the film within a desired range, the etching resistance of the film can be improved. In other words, by modifying the film using the second modifier as described above, the first film can be modified into a second film that exhibits both ashing resistance and etching resistance.

[0093] (The second predetermined number of times is performed, step S23) In this step, if the number of cycles in which steps S15 to S22 are performed non-simultaneously is less than a second predetermined number of times (m times, where m is an integer of 1 or more), the pressure in the processing chamber 201 and the wafer 200 in the processing chamber 201 are adjusted to the desired pressure and temperature in the first film formation process described above (step S24) by the same procedure as in step S12 described above, and the process returns to step S15 described above. By performing the cycle including steps S15 to S22 a second predetermined number of times, a film containing predetermined elements, C, and N with a desired film thickness can be formed on the wafer 200. That is, in this embodiment, a film containing predetermined elements, C, and N with a desired film thickness is formed on the wafer 200 by executing the cycle including the film formation process (excluding the pre-flow gas supply step) and the modification process a second predetermined number of times. Note that the pre-flow gas supply step may be performed not only once before this cycle as in this embodiment, but also with each cycle.

[0094] By performing steps S20 to S22 once for every multiple cycles in which steps S15 to S18 described above are performed non-simultaneously, the number of times steps S20 to S22 are performed can be reduced, thereby improving throughput.

[0095] In this modification process (second film formation process), the first film is modified into the second film such that the reduction in the H content of the first film is greater than the reduction in the C content of the first film. In other words, in this process, the first film is modified into the second film in such a way that the reduction in the H content is reduced while minimizing the reduction in the C content of the first film.

[0096] Figure 5(A) shows the state of the wafer surface 200 when NH3 gas is supplied to the first film formed on the wafer 200, and Figure 5(B) shows the state of the wafer surface 200 when N2H4 gas is supplied to the first film formed on the wafer 200.

[0097] As shown in Figure 5(A), NH3 is composed only of NH bonds, which have relatively high activation energies, making it less susceptible to thermal decomposition into highly reactive intermediates. Furthermore, because NH3 requires high activation energies to react with the CH bonds, Si-H bonds, and Si-Cl bonds remaining in the first film, it is less likely to cause reactions that cleave these bonds. In other words, NH3 has a weak effect in removing these bonds in the first film. For example, the activation energy (Ea(H)) required to react NH3 with the Si-H bonds in the first film to remove H is 1.95, and the activation energy (Ea(Cl)) required to react NH3 with the Si-Cl bonds to remove Cl is 1.33.

[0098] On the other hand, as shown in Figure 5(B), N2H4 contains an NN bond with a relatively low activation energy, making it readily thermally decomposed into the highly reactive intermediate NH2. Furthermore, because the intermediate NH2 contains N with an unbonded bond, the activation energy required to cause a reaction with the CH bond, Si-H bond, and Si-Cl bond remaining in the first film is low, making it easy to cause reactions that cleave these bonds. In other words, N2H4 (and its intermediate NH2) has a strong effect in removing these bonds in the first film. According to an example of molecular simulation calculation results performed by the discloser, the activation energy (Ea(H)) required to react NH2 with the Si-H bond in the first film to remove H is 0.01, and the activation energy (Ea(Cl)) required to react NH2 with the Si-Cl bond to remove Cl is 0.16.

[0099] In other words, the activation energy required to react and remove H atoms bonded to C atoms in the first membrane with NH2, an intermediate produced by the decomposition of N2H4 as a second modifier, is lower than the activation energy required to remove H atoms bonded to C atoms in the first membrane with NH3, a first modifier. That is, by reacting NH2, an intermediate of N2H4 that is more reactive than NH3, with H atoms bonded to C atoms in the first membrane, H atoms can be removed from the first membrane.

[0100] Furthermore, the activation energy required for NH2 to react with and remove Cl bonded to Si in the first film is lower than the activation energy required for NH3 to remove Cl bonded to Si in the first film. In other words, by reacting NH2, an intermediate of N2H4 that is more reactive than NH3, with Cl bonded to Si in the first film, Cl can be removed from the first film.

[0101] In other words, in this modification process, the first film is modified using a second modifier to reduce the content ratio of H bonded to predetermined elements in the first film, such as H bonded to C and H bonded to N, thereby modifying the first film into a second film. That is, the content ratio (concentration) of H bonded to Si, H bonded to C, and H bonded to N in the first film is reduced. Specifically, by supplying the second modifier, the aforementioned intermediate generated from the second modifier reacts with, for example, Si-H bonds, CH bonds, NH bonds, etc., contained in the first film, thereby removing H from the first film. By reducing the content ratio of H in the film, film properties such as ashing resistance can be improved.

[0102] Furthermore, in this process, the first film is modified into the second film in such a way that halogen elements, such as Cl, contained in the first film are removed. In other words, the content ratio of Cl bonded to C, Cl bonded to Si, Cl bonded to N, etc., remaining in the first film is reduced. Specifically, by supplying a second modifier, the aforementioned intermediate generated from the second modifier reacts with the C-Cl bonds, Si-Cl bonds, N-Cl bonds, etc., contained in the first film, thereby removing Cl from the first film. By reducing the content ratio of halogen elements such as Cl in the film, film properties such as ashing resistance can be improved.

[0103] Furthermore, the H concentration in the first film before the modification process is, for example, 20-30 atomic%, and the H concentration in the second film after the modification process is, for example, 0-10 atomic%. If the H concentration in the second film exceeds 10 atomic%, it may not be possible to obtain a practical range of ashing resistance. By keeping the H concentration in the second film below 10 atomic%, the ashing resistance of the second film in plasma ashing using oxygen (O2) plasma, etc., can be improved to a practical range.

[0104] Here, the C concentration in the second film after the modification process is maintained within a desired range that maintains etching resistance, for example, 5 to 30 atomic%, preferably 10 to 30 atomic%, etc.

[0105] If the carbon concentration in the second film is less than 5 atomic%, the etching resistance may decrease significantly. By increasing the carbon concentration in the second film to 5 atomic% or higher, the etching resistance can be improved when wet etching is performed on the second film using, for example, a diluted aqueous solution of hydrogen fluoride (HF). Furthermore, by increasing the carbon concentration in the second film to 10 atomic% or higher, the etching resistance of the second film can be improved to a practical level.

[0106] Furthermore, if the carbon concentration in the second film exceeds 30 atomic%, practical etching resistance may not be achieved. By keeping the carbon concentration in the second film below 30 atomic%, the etching resistance of the second film can be improved to a practical level.

[0107] In other words, according to this embodiment, both the C concentration and H concentration in the film can be modified to fall within the desired ranges described above, thereby forming a film that exhibits both ashing resistance and etching resistance.

[0108] (Purge and return to atmospheric pressure, step S25) Valves 243c and 243d are opened, and inert gas is supplied into the processing chamber 201 from gas supply pipes 232c and 232d, respectively, and exhausted through exhaust pipe 231. The inert gas acts as a purge gas. This purges the processing chamber 201, removing any remaining gases and by-products from the processing chamber 201 (purging). Subsequently, the atmosphere inside the processing chamber 201 is replaced with the inert gas (inert gas replacement), and the pressure inside the processing chamber 201 is returned to atmospheric pressure (restoration to atmospheric pressure).

[0109] (Boat unloading and wafer discharge, step S26) The seal cap 219 is lowered by the boat elevator 115, opening the lower end of the reaction tube 203. Then, the processed wafer 200, supported by the boat 217, is unloaded from the lower end of the reaction tube 203 to the outside of the reaction tube 203 (boat unloading). The processed wafer 200 is removed from the boat 217 (wafer discharge).

[0110] (3) Effects of this embodiment According to this embodiment, one or more of the following effects can be obtained.

[0111] (a) Impurities such as H and Cl contained in the film are reduced, and a film with high film density and excellent ashing resistance can be formed. (b) While maintaining the C concentration in the film within a desired range, impurities such as H and Cl are reduced, and a film with excellent etching resistance can be formed. (c) In other words, the film formed on the wafer 200 can be modified to a film that has both ashing resistance and etching resistance. (d) The effects described above can be similarly obtained when forming and modifying CN-containing films other than SiCN films.

[0112] <Other aspects of this disclosure> The aspects of this disclosure have been specifically described above. However, this disclosure is not limited to the aspects described above and can be modified in various ways without departing from its essence.

[0113] (modified version) Next, a modified example of the substrate processing process described above will be explained using Figure 6.

[0114] In this modified example, a modification step is included within the film formation step described above. That is, after steps S31 to S38, which perform the same processing as steps S11 to S18 described above, steps S39 and S40, which perform the same processing as steps S21 and S22 in the modification step described above, are performed. Then, as step S41, the cycle of performing steps S35 to S40 is repeated a third predetermined number of times (p times, where p is an integer of 1 or more).

[0115] By performing the second cycle a predetermined number of times, a third film of a desired thickness can be formed, similar to the second film described above, in which impurities such as H and Cl are reduced while the C concentration is maintained within the desired range. In other words, the same effects as in the above-described embodiment can be obtained in this modified example as well. Furthermore, in this modified example, by performing a modification treatment to remove H, Cl, etc., while depositing the first film formed on the surface of the wafer 200, the density of NH terminations on the surface of the wafer 200, which serve as adsorption sites for raw materials, can be increased, thereby improving the deposition rate, which is the formation rate of the first film. In addition, the processing time can be shortened, and throughput can be improved.

[0116] (Other aspects) For example, the above-described embodiment was explained using the case where the predetermined element contained in the raw material gas is Si. However, this disclosure is not limited to such embodiments. For example, the predetermined element may be a metallic element such as titanium (Ti), zirconium (Zr), hafnium (Hf), tantalum (Ta), niobium (Nb), aluminum (Al), molybdenum (Mo), tungsten (W), or germanium (Ge). In these cases, metallic carbonitride films such as titanium carbonitride (TiCN film), zirconium carbonitride (ZrCN film), hafnium carbonitride (HfCN film), tantalum carbonitride (TaCN film), niobium carbonitride (NbCN film), aluminum carbonitride (AlCN film), molybdenum carbonitride (MoCN film), tungsten carbonitride (WCN film), or germanium carbonitride (GeCN film) are formed. In these cases as well, the same effects as in the above-described embodiment can be obtained.

[0117] Furthermore, although the above embodiment was described using a case in which a first film containing predetermined elements, N, C, and C-bonded H is formed on a wafer 200 on which a Si film is formed on the surface during the film formation process, the present disclosure is not limited thereto, and can also be suitably used in cases where an oxide film such as a silicon oxide film (SiO film) or a nitride film such as a silicon nitride film (SiN film) is formed on the surface of the wafer 200, or when the first film is formed on the surface of the wafer 200 itself.

[0118] Furthermore, the above embodiment was described using the case in which the first film formation step and the modification step are carried out continuously (in-situ) in the same processing chamber 201. This disclosure is not limited thereto, and the first film formation step and the modification step may be carried out separately (ex-situ) in different processing chambers (processing containers). In this case as well, the same effects as in the above embodiment can be obtained. When these steps are carried out in-situ, contamination of the substrate and changes in the surface condition of the substrate that may occur due to the removal of the substrate from the processing chamber or the loading of the substrate from outside the processing chamber between steps can be suppressed. Also, when these processes are carried out in-situ, the transition time between steps can be shortened. On the other hand, when these steps are carried out ex-situ, each step can be carried out in parallel in different processing chambers, thereby increasing productivity.

[0119] Furthermore, it is preferable that the recipes used for substrate processing be prepared individually according to the processing content and stored in the storage device 121c via a telecommunications line or external storage device 123. When starting substrate processing, it is preferable that the CPU 121a appropriately selects the appropriate recipe from among the multiple recipes stored in the storage device 121c according to the processing content. This makes it possible to form films of various film types, composition ratios, film quality, and film thickness with good reproducibility using a single substrate processing device. In addition, it is possible to reduce the burden on the operator and start substrate processing quickly while avoiding operational errors.

[0120] The above-mentioned recipes are not limited to newly created ones; they may also be prepared, for example, by modifying existing recipes already installed in the board processing device. When modifying a recipe, the modified recipe may be installed in the board processing device via a telecommunications line or a recording medium containing the recipe. Alternatively, existing recipes already installed in the board processing device may be directly modified by operating the input / output device 122 provided in the existing board processing device.

[0121] The above-described embodiments illustrate an example of processing a film using a batch-type substrate processing apparatus that processes multiple substrates at once. This disclosure is not limited to the above-described embodiments and can be suitably applied, for example, to processing a film using a single-wafer substrate processing apparatus that processes one or several substrates at once. Furthermore, the above-described embodiments illustrate an example of processing a film using a substrate processing apparatus having a hot-wall type processing furnace. This disclosure is not limited to the above-described embodiments and can be suitably applied to processing a film using a substrate processing apparatus having a cold-wall type processing furnace.

[0122] Even when using these substrate processing devices, film deposition can be performed using the same processing procedures and conditions as described above, and the same effects as described above can be obtained.

[0123] Furthermore, the above-described embodiments and modifications can be used in combination as appropriate. The processing procedure and processing conditions in this case can be the same as, for example, the processing procedure and processing conditions of the above-described embodiments and modifications. [Explanation of Symbols]

[0124] 200 wafers (substrates)

Claims

1. (a) A step of forming a first film on the substrate containing the predetermined element, nitrogen, carbon, and carbon-bonded hydrogen by performing a cycle that includes the steps of supplying a raw material containing a predetermined element, carbon, and hydrogen to the substrate and supplying a first modifier containing nitrogen to the substrate a predetermined number of times, (b) A step of modifying the first film to a second film containing the predetermined element, carbon, and nitrogen, in which the content ratio of hydrogen bonded to carbon is reduced compared to the first film, by supplying a second modifier, which is a compound or derivative thereof, different from the first modifier, and containing a nitrogen-hydrogen bond and a nitrogen-to-nitrogen bond in one molecule. A substrate processing method having the following characteristics.

2. The substrate processing method according to claim 1, wherein after (a), (b) is started without exposing the substrate to an oxygen-containing atmosphere.

3. (b) The substrate processing method according to claim 1, wherein the first film is modified so as to reduce the content ratio of carbon-hydrogen bonds over the entire thickness direction of the first film.

4. (b) The substrate processing method according to claim 1, wherein the first film is modified into the second film such that the reduction in the hydrogen content ratio contained in the first film is greater than the reduction in the carbon content ratio contained in the first film.

5. The substrate processing method according to claim 1, wherein the cycle is performed multiple times until the first film reaches a desired thickness.

6. (b) The substrate processing method according to claim 1, wherein the second modifier is supplied to the substrate in a non-plasma state.

7. The substrate treatment method according to claim 1, wherein the first modifier does not contain nitrogen-to-nitrogen bonds in a single molecule.

8. The substrate treatment method according to claim 7, wherein the first modifier is a hydrogen nitride-based compound.

9. (b) The substrate treatment method according to claim 1, wherein an intermediate containing nitrogen having an unbonded bond in one molecule, generated from the second modifier, is reacted with hydrogen bonded to the carbon contained in the first film, thereby removing the hydrogen from the first film.

10. The substrate processing method according to claim 1, wherein the activation energy of the intermediate produced by the decomposition of the second modifier, which removes hydrogen bonded to the carbon contained in the first film, is smaller than the activation energy of the first modifier, which removes hydrogen bonded to the carbon contained in the first film.

11. The substrate treatment method according to any one of claims 1 to 10, wherein the second modifier comprises at least one compound or derivative from diazene, hydrazine, triazene, triazane, monomethylhydrazine, 1,1-dimethylhydrazine, and 1,2-dimethylhydrazine.

12. The substrate processing method according to any one of claims 1 to 10, wherein the raw material comprises a compound containing the predetermined element, carbon, hydrogen, and a halogen element in one molecule, and in (b), the first film is modified into the second film so as to remove the halogen element contained in the first film.

13. (b) The substrate processing method according to any one of claims 1 to 10, wherein the first film is modified into the second film in such a way that the content ratio of hydrogen bonded to the predetermined element contained in the first film is reduced.

14. The substrate processing method according to any one of claims 1 to 10, wherein the partial pressure of the second modifier in (b) is smaller than the partial pressure of the first modifier in (a).

15. The substrate processing method according to any one of claims 1 to 10, wherein the temperature of the substrate in (b) is lower than the temperature of the substrate in (a).

16. A substrate processing method according to any one of claims 1 to 10, further comprising the step of purging the space in which the substrate exists after (a) and before (b).

17. The predetermined number of times is set to one, A substrate processing method according to any one of claims 1 to 10, comprising performing a second cycle including (a) and (b) multiple times.

18. (a) A step of forming a first film on the substrate containing the predetermined element, nitrogen, carbon, and carbon-bonded hydrogen by performing a cycle that includes the steps of supplying a raw material containing a predetermined element, carbon, and hydrogen to the substrate and supplying a first modifier containing nitrogen to the substrate a predetermined number of times, (b) A step of modifying the first film to a second film containing the predetermined element, carbon, and nitrogen, in which the content ratio of hydrogen bonded to carbon is reduced compared to the first film, by supplying a second modifier, which is a compound or derivative thereof, different from the first modifier, and containing a nitrogen-hydrogen bond and a nitrogen-to-nitrogen bond in one molecule. A method for manufacturing a semiconductor device having [a certain feature].

19. (a) A procedure to form a first film on the substrate containing the predetermined element, nitrogen, carbon, and carbon-bonded hydrogen by performing a cycle a predetermined number of times, which includes the steps of supplying a raw material containing a predetermined element, carbon, and hydrogen to the substrate, and supplying a first modifier containing nitrogen to the substrate. (b) A procedure for modifying the first film to a second film containing the predetermined element, carbon, and nitrogen, in which the content ratio of hydrogen bonded to carbon is reduced compared to the first film, by supplying a second modifier, which is a compound or derivative thereof, different from the first modifier, and which contains a nitrogen-hydrogen bond and a nitrogen-to-nitrogen bond in one molecule. A program that causes a circuit board processing device to execute commands via a computer.

20. A raw material supply system that supplies raw materials containing predetermined elements, carbon, and hydrogen to a substrate, A first modifier supply system that supplies a first modifier containing nitrogen to the substrate, A second modifier supply system supplies a second modifier to the substrate, which is a compound or derivative thereof containing a nitrogen-hydrogen bond and a nitrogen-to-nitrogen bond in one molecule, different from the first modifier. (a) A process of forming a first film on the substrate containing the predetermined element, nitrogen, carbon, and carbon-bonded hydrogen by performing a cycle including the process of supplying the raw material to the substrate and the process of supplying the first modifier to the substrate a predetermined number of times, (b) A control unit configured to control the raw material supply system, the first modifier supply system, and the second modifier supply system to perform a process of supplying the second modifier to the substrate on which the first film is formed, thereby modifying the first film into a second film containing the predetermined element, carbon, and nitrogen, in which the content ratio of hydrogen bonded to the carbon is reduced compared to the first film. A substrate processing apparatus.

Images