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

Abstract

The present application is a substrate processing method, a semiconductor device manufacturing method, a substrate processing apparatus, and a recording medium to improve the characteristics of a film formed on a substrate. The substrate processing method has a step of forming a film containing silicon, a predetermined element, and nitrogen on a substrate by repeating a predetermined number of cycles, the cycle including (a) a step of supplying a first gas containing silicon to the substrate to form a first layer, (b) a step of supplying a second gas containing silicon and having a different molecular structure from the first gas to the substrate to form a second layer, (c) a step of supplying a third gas containing the predetermined element to the substrate, and (d) a step of supplying a fourth gas containing nitrogen to the substrate to modify the first layer and the second layer; the predetermined element is an element capable of forming a defect in the film, and in the cycle, each of the steps (a) to (d) is performed in any one of the sequences of (a)(c)(b)(d), (c)(a)(b)(d), or (c)(a)(c)(b)(d).

Description

Technical Field

[0001] This disclosure relates to a substrate processing method, a method for manufacturing a semiconductor device, a substrate processing apparatus, and a recording medium. Background Technology

[0002] As a step in the manufacturing process of a semiconductor device, a process of forming a film on a substrate is sometimes performed (e.g., Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2021 / 053756 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] The purpose of this invention is to provide a technique that can improve the properties of films formed on a substrate.

[0008] Methods for solving problems

[0009] According to one aspect of this disclosure, a substrate processing method is provided, comprising a step of forming a film containing silicon, a predetermined element, and nitrogen on a substrate by performing cycles including (a), (b), (c), and (d) a predetermined number of times.

[0010] (a) A process of forming a first layer by supplying a first gas containing silicon to the substrate.

[0011] (b) A process of forming a second layer by supplying a second gas containing silicon and having a molecular structure different from the first gas to the substrate.

[0012] (c) The process of supplying the substrate with a third gas containing the predetermined element, and

[0013] (d) A process of supplying a fourth gas containing nitrogen to the substrate to modify the first layer and the second layer.

[0014] As the aforementioned predetermined element, an element capable of forming defects in the aforementioned film is used.

[0015] In the above cycle, each step of (a) to (d) is performed in any order of (a)(c)(b)(d), (c)(a)(b)(d), or (c)(a)(c)(b)(d).

[0016] Invention Effects

[0017] According to this disclosure, a technique is available that can improve the properties of a film formed on a substrate. Attached Figure Description

[0018] Figure 1 This is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus preferred in one embodiment of the present disclosure, and is a diagram showing the processing furnace 202 portion in a longitudinal cross-sectional view.

[0019] Figure 2 This is a schematic diagram of a vertical processing furnace of a substrate processing apparatus preferably used in one embodiment of the present disclosure. Figure 1 The AA-line cross-sectional view shows part of the processing furnace 202.

[0020] Figure 3 This is a schematic configuration diagram of the controller 121 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 121.

[0021] Figure 4 This is a diagram illustrating the processing flow in one embodiment of this disclosure.

[0022] Figure 5 This is a diagram illustrating the processing flow in a variation of this disclosure, Example 1.

[0023] Figure 6 This is a diagram illustrating the processing flow in Modification 3 of this disclosure.

[0024] Figure 7 This is a diagram illustrating a film formed in a substrate processing apparatus preferably used in one embodiment of the present disclosure.

[0025] Figure 8 This is a graph showing the measurement results in the examples.

[0026] Symbol Explanation

[0027] 200: Wafer (substrate). Detailed Implementation

[0028] <One way this disclosure>

[0029] The following is mainly based on Figures 1-4 One aspect of this disclosure will be described. Furthermore, the accompanying drawings used in the following description are schematic, and the dimensional relationships and ratios of the elements shown may not necessarily correspond to reality. Additionally, the dimensional relationships and ratios of the elements may not be consistent between different drawings.

[0030] (1) Composition of substrate processing device

[0031] like Figure 1As 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 by a retaining plate. The heater 207 also functions as an activation mechanism (activation unit) that uses heat to activate (excite) the gas.

[0032] Inside 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 is formed into a cylindrical shape that is closed at the top and open at the bottom. 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 is formed into a cylindrical shape that is open at both the top and bottom. The upper end of the manifold 209 engages with the lower end of the reaction tube 203 to support the reaction tube 203. An O-ring 220a is provided between the manifold 209 and the reaction tube 203 as a sealing component. The reaction tube 203 is installed vertically, just 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 hollow part of the cylindrical part of the processing container. The processing chamber 201 is configured to accommodate a wafer 200, which serves as a substrate. Processing of the wafer 200 is performed within the processing chamber 201.

[0033] Inside the processing chamber 201, nozzles 249a to 249c, serving as first to third supply units, are respectively installed through the side wall of the manifold 209. These nozzles are also referred to as the first to third nozzles. The nozzles 249a to 249c are made of heat-resistant materials such as quartz or SiC. Each of the nozzles 249a to 249c is connected to a gas supply pipe 232a to 232c. The nozzles 249a to 249c are different nozzles, and each nozzle 249a and 249c is arranged adjacent to nozzle 249b.

[0034] In gas supply pipes 232a to 232c, mass flow controllers (MFCs) 241a to 241c (flow controllers, flow control units) and valves 243a to 243c (on / off valves) are sequentially installed from the upstream side of the airflow. Gas supply pipes 232d and 232e are connected to gas supply pipe 232a downstream of valve 243a. Gas supply pipes 232f and 232g are connected to gas supply pipes 232b and 232c downstream of valves 243b and 243c, respectively. In gas supply pipes 232d to 232g, MFCs 241d to 241g and valves 243d to 243g are sequentially installed from the upstream side of the airflow. Gas supply pipes 232a to 232g are made of, for example, a metal material such as SUS.

[0035] like Figure 2 As shown, in the annular space between the inner wall of the reaction tube 203 and the wafer 200 from a top-view perspective, nozzles 249a to 249c are respectively arranged upright along the lower to upper part of the inner wall of the reaction tube 203, facing upwards towards the arrangement direction of the wafer 200. That is, nozzles 249a to 249c are respectively arranged in the area horizontally surrounding the wafer arrangement area on the side of the wafer arrangement area where the wafer 200 is arranged. From a top-view perspective, nozzle 249b is arranged opposite to the exhaust port 231a (described later) in a straight line across the center of the wafer 200 that has been moved into the processing chamber 201. Nozzles 249a and 249c are arranged along the inner wall of the reaction tube 203 (outer periphery of the wafer 200) from both sides, sandwiching a straight line L passing through the center of nozzle 249b and exhaust port 231a. Straight line L is also a straight line passing through the center of nozzle 249b and wafer 200. That is, nozzle 249c can also be described as being positioned on the opposite side of nozzle 249a, separated by a straight line L. Nozzles 249a and 249c are arranged linearly symmetrically about the straight line L. Gas supply holes 250a and 250c are respectively provided on the sides of nozzles 249a and 249c. These gas supply holes 250a and 250c open in a manner opposite (opposite) to exhaust port 231a when viewed from above, allowing gas to be supplied towards wafer 200. Multiple gas supply holes 250a and 250c are provided from the bottom to the top of reaction tube 203.

[0036] A first gas containing silicon (Si) is supplied into the processing chamber 201 from the gas supply pipe 232a via MFC 241a, valve 243a, and nozzle 249a. The first gas is used as a raw material gas.

[0037] A third gas containing a predetermined element is supplied into the processing chamber 201 from the gas supply pipe 232b via MFC 241b, valve 243b, and nozzle 249b. It should be noted that the predetermined element refers to an element that can form defects in the film formed on the wafer 200 through the film-forming process described later. At least one of carbon (C) or boron (B) can be used as the predetermined element.

[0038] A fourth gas containing nitrogen (N) is supplied into the processing chamber 201 from the gas supply pipe 232c via MFC 241c, valve 243c, and nozzle 249c. The fourth gas is used as a reaction gas.

[0039] A second gas containing Si is supplied into the processing chamber 201 through gas supply pipe 232d, MFC 241d, valve 243d, gas supply pipe 232a, and nozzle 249a. It should be noted that the second gas is a gas with a molecular structure different from the first gas and is used as a raw material gas.

[0040] Inactive gases are supplied to the treatment chamber 201 from gas supply pipes 232e-232g via MFCs 241e-241g, valves 243e-243g, gas supply pipes 232a-232c, and nozzles 249a-249c. These inactive gases function as purge gas, carrier gas, and dilution gas.

[0041] The first gas supply system mainly consists of gas supply pipe 232a, MFC 241a, and valve 243a. The third gas supply system mainly consists of gas supply pipe 232b, MFC 241b, and valve 243b. The fourth gas supply system mainly consists of gas supply pipe 232c, MFC 241c, and valve 243c. The second gas supply system mainly consists of gas supply pipe 232d, MFC 241d, and valve 243d. The inactive gas supply system mainly consists of gas supply pipes 232e-232g, MFC 241e-241g, and valves 243e-243g.

[0042] Any or all of the aforementioned supply systems can be configured as an integrated supply system 248, comprising valves 243a-243g, MFCs 241a-241g, etc. The integrated supply system 248 is connected to gas supply pipes 232a-232g, and is configured to control the supply of various substances (various gases) into the gas supply pipes 232a-232g (i.e., the opening and closing of valves 243a-243g) and the flow regulation using MFCs 241a-241g, etc., via the controller 121 described later. The integrated supply system 248 can be configured as a single unit or a segmented integrated unit, allowing for installation and removal of the integrated supply system 248 relative to the gas supply pipes 232a-232g, etc., and enabling maintenance, replacement, and addition of the integrated supply system 248 on a unit-by-unit basis.

[0043] An exhaust port 231a is provided below the side wall of the reaction tube 203 for exhausting the atmosphere inside the processing chamber 201. For example... Figure 2As shown, the exhaust port 231a, viewed from above, is positioned opposite (opposite to) the nozzles 249a-249c (gas supply ports 250a-250c) across the wafer 200. The exhaust port 231a may also be positioned along the lower to upper part of the sidewall of the reaction tube 203 (i.e., along the wafer arrangement area). The exhaust port 231a is connected to the exhaust pipe 231. In the exhaust pipe 231, a vacuum pump 246, serving as a vacuum exhaust device, is connected via a pressure sensor 245 (which acts as a pressure detector, or pressure detection unit) and an APC (Auto Pressure Controller) valve 244 (which acts as a pressure regulator, or pressure adjustment unit). By opening and closing the APC valve 244 while the vacuum pump 246 is operating, vacuum exhaust and vacuum exhaust stopping can be performed within the processing chamber 201. The APC valve 244 is also configured to adjust its opening based on pressure information detected by the pressure sensor 245 when the vacuum pump 246 is operating, thereby adjusting the pressure within the processing chamber 201. The exhaust system mainly consists of the exhaust pipe 231, the APC valve 244, and the pressure sensor 245. Integrating the vacuum pump 246 into the exhaust system is also an option.

[0044] Below the manifold 209, a sealing cap 219, serving as a furnace opening cover, is provided to airtightly seal the lower opening of the manifold 209. The sealing cap 219 is made of a metal material such as SUS and is formed in a disc shape. An O-ring 220b, serving as a sealing component, is provided on the upper surface of the sealing cap 219 and abuts against the lower end of the manifold 209. Below the sealing cap 219, a rotation mechanism 267 is provided to rotate the wafer cassette 217 (described later). The rotation shaft 255 of the rotation mechanism 267 passes through the sealing cap 219 and is connected to the wafer cassette 217. The rotation mechanism 267 is configured to rotate the wafer 200 by rotating the wafer cassette 217. The sealing cap 219 is configured to move vertically via a wafer cassette lift 115, which is a lifting mechanism located outside the reaction tube 203. The wafer cassette lift 115 is configured as a conveying device (conveyor) that moves the wafer 200 into and out of the processing chamber 201 by raising and lowering the sealing cap 219. The conveying device functions as a supply device for providing wafers 200 into the processing chamber 201.

[0045] Below the manifold 209, there is a baffle 219s, which acts as a furnace opening cover, capable of sealing the lower opening of the manifold 209 hermetically when the sealing cap 219 is lowered and the wafer cassette 217 is removed from the processing chamber 201. The baffle 219s is made of a metal material such as SUS and is formed in a disc shape. An O-ring 220c, which abuts against the lower end of the manifold 209, is provided on the upper surface of the baffle 219s as a sealing component. The opening and closing action (lifting action, rotating action, etc.) of the baffle 219s is controlled by the baffle opening and closing mechanism 115s.

[0046] The wafer cassette 217, serving as a substrate support, is configured to support multiple wafers (e.g., 25 to 200 wafers) 200 arranged horizontally and aligned with each other at their centers in a vertical direction, i.e., arranged at intervals. The wafer cassette 217 is made of heat-resistant materials such as quartz or SiC. At the bottom of the wafer cassette 217, multiple layers of heat-insulating plates 218, such as those made of heat-resistant materials like quartz or SiC, are supported.

[0047] A temperature sensor 263, serving as a temperature detector, is installed inside the reaction tube 203. By adjusting the electrical current supplied to the heater 207 based on the temperature information detected by the temperature sensor 263, the temperature within the processing chamber 201 is adjusted to achieve the desired temperature distribution. The temperature sensor 263 is disposed along the inner wall of the reaction tube 203.

[0048] like Figure 3 As shown, the controller 121, serving as the control unit (control unit), 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 interface 121d. The RAM 121b, storage device 121c, and I / O interface 121d are configured to exchange data with the CPU 121a via an internal bus 121e. The controller 121 is connected to an input / output device 122, such as a touch panel. Furthermore, an external storage device 123 can be connected to the controller 121.

[0049] Storage device 121c is configured such as flash memory, HDD (Hard Disk Drive), SSD (Solid State Drive), etc. Storage device 121c stores, in a readable manner, a control program that controls the operation of the substrate processing apparatus, and a process recipe that describes the substrate processing process and conditions, as described later. The process recipe is a combination of processes that, by having the substrate processing apparatus execute each process in the substrate processing described later via controller 121, can obtain a predetermined result, and functions as a program. Hereinafter, process recipe, control program, etc., will be collectively referred to as a program. Additionally, process recipe will be simply referred to as recipe. When using the term "program" in this specification, sometimes only recipe is included, sometimes only control program is included, or sometimes both are included. RAM 121b is configured as a storage area (working area) that temporarily holds programs, data, etc., read by CPU 121a.

[0050] I / O interface 121d is connected to the aforementioned MFC241a~241g, valves 243a~243g, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotating mechanism 267, wafer box elevator 115, baffle switch mechanism 115s, etc.

[0051] CPU 121a is configured to read and execute control programs from storage device 121c, and to read recipes from storage device 121c based on input commands from input / output device 122. CPU 121a is configured to control the following actions according to the read recipe: flow rate adjustment of various substances (various gases) by MFCs 241a to 241g, opening and closing of valves 243a to 243g, opening and closing of APC valve 244, pressure adjustment by APC valve 244 based on pressure sensor 245, start and stop of vacuum pump 246, temperature adjustment by heater 207 based on temperature sensor 263, rotation and speed adjustment of wafer cassette 217 by rotation mechanism 267, lifting and lowering of wafer cassette 217 by wafer cassette elevator 115, and opening and closing of baffle 219s by baffle switch mechanism 115s.

[0052] The controller 121 is configured to install the aforementioned program stored in the external storage device 123 onto 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 constitute a computer-readable recording medium. Hereinafter, they will also be collectively referred to as a recording medium. When the term "recording medium" is used in this specification, sometimes only the storage device 121c is included, sometimes only the external storage device 123 is included, or sometimes both are included. Furthermore, providing the program to the computer may also be done without using the external storage device 123, but rather using communication methods such as the Internet or a dedicated line.

[0053] (2) Substrate processing process

[0054] Regarding the example of using the aforementioned substrate processing apparatus as a step in the manufacturing process of a semiconductor device to process the wafer 200, which serves as a substrate, specifically a film formation process example where a film is formed on the wafer 200, the main method used is... Figure 4 The following description will explain the operation of each component constituting the substrate processing apparatus, which is controlled by the controller 121.

[0055] In this film formation process, a silicon carbonitride film (SiCN film or C-doped SiN film) is formed on a wafer 200 by performing the following cycle a predetermined number of times (n times, where n is an integer greater than or equal to 1) as a film containing Si, C, and N. The cycle includes: step a, supplying a first gas containing Si to the wafer 200 to form a first layer; step b, supplying a second gas containing Si and having a molecular structure different from the first gas to the wafer 200 to form a second layer; step c, supplying a third gas containing, for example, C as a predetermined element to the wafer 200; and step d, supplying a fourth gas containing N to the wafer 200 to modify the first and second layers.

[0056] It should be noted that in the above cycle, steps a through d are performed non-simultaneously in any of the following orders: a, c, b, d; c, a, b, d; or c, a, c, b, d. Additionally, in Figure 4 The example shown illustrates steps a through d performed non-simultaneously in the order a, c, b, d. Additionally, in... Figure 4 In the diagram, the implementation periods of steps a, b, c, and d are represented as a, b, c, and d, respectively.

[0057] In the following description, an example of a charge trapping (charge capture) film formed of SiCN film will be explained.

[0058] In this specification, for convenience, the above-described processing flow is sometimes represented as follows. The same notation is also used in the following descriptions of variations, other methods, etc.

[0059] (First gas → Third gas → Second gas → Fourth gas) × n → SiCN

[0060] As used in this specification, the term "wafer" sometimes refers to the wafer itself, and sometimes to a laminate of the wafer and a predetermined layer or film formed on its surface. The term "surface of the wafer" sometimes refers to the surface of the wafer itself, and sometimes to the surface of a predetermined layer or the like formed on the wafer. In this specification, when it is described as "forming a predetermined layer on the wafer," it sometimes means that the predetermined layer is formed directly on the surface of the wafer itself, and sometimes it means that the predetermined layer is formed on a layer or the like formed on the wafer. The term "substrate" is used in the same way as the term "wafer."

[0061] (Wafer loading and wafer cassette mounting)

[0062] When multiple wafers 200 are loaded (wafer loading) into the wafer cassette 217, the baffle 219s is moved by the baffle switching mechanism, thereby opening the lower opening of the manifold 209 (baffle opening). Afterwards, as... Figure 1 As shown, a wafer cassette 217 supporting multiple wafers 200 is lifted by a wafer cassette lifter 115 and moved into the processing chamber 201 (wafer cassette loading). In this state, the sealing cap 219 seals the lower end of the manifold 209 via an O-ring 220b. Thus, the wafers 200 are supplied into the processing chamber 201.

[0063] (Pressure and temperature adjustment)

[0064] After the wafer cassette is assembled, vacuum pump 246 is used to perform vacuum venting (pressure reduction venting) to bring the processing chamber 201, the space containing the wafer 200, to the desired pressure (vacuum level). At this time, the pressure within the processing chamber 201 is measured by pressure sensor 245, and the APC valve 244 is controlled based on this measured pressure information. Additionally, heating is performed by heater 207 to bring the wafer 200 within the processing chamber 201 to the desired processing temperature. At this time, the electrical current supplied to heater 207 is controlled based on temperature information detected by temperature sensor 263 to achieve the desired temperature distribution within the processing chamber 201. Furthermore, rotation of the wafer 200 is initiated using rotation mechanism 267. Venting of the processing chamber 201, heating of the wafer 200, and rotation are all performed continuously, at least until the processing of the wafer 200 is completed.

[0065] (Film-forming treatment)

[0066] Then, perform the following steps a through d in the order of a, c, b, d.

[0067] [Step a]

[0068] In step a, a first gas is supplied to the wafer 200 in the processing chamber 201.

[0069] Specifically, valve 243a is opened, allowing the first gas to flow into gas supply pipe 232a. The first gas, with its flow rate regulated by MFC 241a, is supplied into processing chamber 201 via nozzle 249a and discharged from exhaust port 231a. At this time, the first gas is supplied to wafer 200 from the side (first gas supply). Then, valves 243e to 243g are opened, supplying inactive gas into processing chamber 201 via nozzles 249a to 249c, respectively. It should be noted that, for the methods described below, the supply of inactive gas may not be necessary.

[0070] The processing conditions for supplying the first gas in this step are exemplified below:

[0071] Processing temperature: 450–750℃, preferably 650–700℃.

[0072] Processing pressure: 20–133 Pa, preferably 40–70 Pa.

[0073] The first gas supply flow rate is 0.01–2 slm, preferably 0.1–1 slm.

[0074] First gas supply time: 6–60 seconds, preferably 10–30 seconds.

[0075] Inactive gas supply flow rate (per gas supply pipe): 0–20 slm.

[0076] By setting the pressure below 133 Pa, although it is also related to other factors such as temperature, the decomposition of the gas can be prevented.

[0077] It should be noted that the numerical ranges expressed in this specification, such as "450~750℃", refer to the lower and upper limits being included within this range. Therefore, for example, "450~750℃" means "above 450℃ and below 750℃". The same applies to other numerical ranges. Furthermore, the processing temperature in this specification refers to the temperature of the wafer 200 or the temperature inside the processing chamber 201, and the processing pressure refers to the pressure inside the processing chamber 201. Additionally, when the supply flow rate includes 0slm, 0slm means that the gas is not supplied. These same principles apply in the following descriptions.

[0078] By supplying a chlorosilane-based gas as the first gas to the wafer 200 under the aforementioned processing conditions, a first layer (containing a Si layer) is formed on the outermost surface of the wafer 200, which serves as a substrate. The first layer is formed through the physical and chemical adsorption of molecules of the chlorosilane-based gas onto the outermost surface of the wafer 200, and the physical and chemical adsorption of molecules of substances derived from the decomposition of a portion of the chlorosilane-based gas onto the outermost surface of the wafer 200. The first layer can also be an adsorption layer (physical adsorption layer, chemical adsorption layer) of molecules of the chlorosilane-based gas and molecules of substances derived from the decomposition of a portion of the chlorosilane-based gas.

[0079] If the processing temperature is below 450°C, Si is difficult to adsorb onto wafer 200, and sometimes it is difficult to form the first layer. By increasing the processing temperature to above 450°C, the first layer can be formed on wafer 200. By increasing the processing temperature to above 650°C, the first layer can be formed more fully on wafer 200.

[0080] If the processing temperature exceeds 750°C, the first gas, such as a chlorosilane-based gas, will thermally decompose, resulting in multiple Si deposits on the wafer 200. This can sometimes make it difficult to form a first layer with a generally uniform thickness of less than one atomic layer. By setting the processing temperature below 750°C, a first layer with a generally uniform thickness of less than one atomic layer can be formed, improving the step coverage characteristics and on-plane thickness uniformity of the first layer. By setting the processing temperature below 700°C, the step coverage characteristics and on-plane thickness uniformity of the first layer can be further improved. Here, a layer with a thickness of less than one atomic layer refers to a discontinuously formed atomic layer, while a layer with a thickness of one atomic layer refers to a continuously formed atomic layer. Furthermore, a layer with a thickness of less than one atomic layer and a generally uniform thickness means that atoms are adsorbed at a generally uniform density on the surface of the wafer 200.

[0081] In this step, the processing temperature is set to a temperature below or lower than the temperature at which the first gas undergoes thermal decomposition (gas-phase decomposition) when the first gas, such as a chlorosilane-based gas, exists alone in the processing chamber 201. As a result, on the outermost surface of the wafer 200, physico-adsorption and chemi-adsorption of molecules of the chlorosilane-based gas and molecules of substances derived from the decomposition of a portion of the chlorosilane-based gas are dominantly (preferably) generated, while Si deposition caused by the thermal decomposition of the chlorosilane-based gas is minimally or almost non-existent. That is, under the above processing conditions, a first adsorption layer (physico-adsorption layer, chemi-adsorption layer) overwhelmingly contains a large number of molecules of the chlorosilane-based gas and molecules of substances derived from the decomposition of a portion of the chlorosilane-based gas, while a deposition layer containing little or almost no Cl-containing Si is formed.

[0082] After the first layer is formed, valve 243a is closed to stop the supply of the first gas to the processing chamber 201. Then, a vacuum is applied to the processing chamber 201 to remove any gaseous substances remaining in the processing chamber 201. At this time, valves 243e to 243g are kept open to maintain the supply of inactive gas to the processing chamber 201. The inactive gas supplied through nozzles 249a to 249c functions as a purge gas, thereby purging the processing chamber 201.

[0083] As an example of the processing conditions for purging in this step, the following are examples:

[0084] Inactive gas supply flow rate (per gas supply pipe): 0.5–20 slm.

[0085] Inactive gas supply time: 1 to 60 seconds, preferably 2 to 20 seconds.

[0086] Other processing conditions are the same as those when the first gas was supplied in this step.

[0087] As the first gas, a silane-based gas containing silicon (Si), which is the main element constituting the film formed on wafer 200, can be used. As a silane-based gas, for example, a gas containing Si and a halogen, i.e., a halosilane-based gas, can be used. Halogens include chlorine (Cl), fluorine (F), bromine (Br), iodine (I), etc. As a halosilane-based gas, for example, the aforementioned chlorosilane-based gas containing Si and Cl can be used.

[0088] As the first gas, tetrachlorosilane (SiCl4, abbreviated as STC), dichlorosilane (SiH2Cl2, abbreviated as DCS), trichlorosilane (SiHCl3, abbreviated as TCS), and other chlorosilane-based gases can be used. One or more of these can be used as the first gas.

[0089] Of these gases, silane-based gases that do not contain Si-Si bonds are preferred as the first gas.

[0090] Inert gases such as nitrogen (N2), argon (Ar), helium (He), neon (Ne), and xenon (Xe) can be used as inert gases. More than one of these can be used as an inert gas. This also applies to the steps described later.

[0091] [Step c]

[0092] In step c, a third gas is supplied to the wafer 200 in the processing chamber 201, that is, to the first layer formed on the wafer 200.

[0093] Specifically, valve 243b is opened, allowing the third gas to flow into gas supply pipe 232b. The flow rate of the third gas is regulated by MFC 241b, and it is supplied into processing chamber 201 via nozzle 249b and discharged from exhaust port 231a. At this time, the third gas is supplied to wafer 200 from the side (third gas supply). Meanwhile, valves 243e to 243g are kept open, and inactive gases are supplied into processing chamber 201 via nozzles 249a to 249c, respectively.

[0094] The processing conditions for supplying the third gas in this step are exemplified below:

[0095] Processing pressure: 10–50 Pa, preferably 15–30 Pa.

[0096] The third gas supply flow rate is 0.05–6 slm, preferably 0.5–2 slm.

[0097] The third gas supply time is 2 to 60 seconds, preferably 4 to 30 seconds.

[0098] The other processing conditions are the same as those when the first gas is supplied in step a.

[0099] By supplying a third gas, for example containing C as a predetermined element, to the first layer formed on the wafer 200 under the above-described processing conditions, C can be adsorbed onto the first layer formed on the wafer 200. By adsorbing C onto the first layer, defects (crystal defects) that trap charge can be formed (introduced) in the nitrided layer formed by cycling, and further in the SiCN film finally formed on the wafer 200.

[0100] After C is adsorbed on the first layer to form a C-containing layer, valve 243b is closed to stop the supply of the third gas to the treatment chamber 201. Then, through the same treatment process and conditions as the purging described above, the gaseous substances remaining in the treatment chamber 201 are removed from the treatment chamber 201 (purging). It should be noted that the treatment temperature during purging in this step is preferably set to the same temperature as the treatment temperature during the supply of the third gas.

[0101] As a third gas, a carbon-containing gas can be used, for example. As a carbon-containing gas, examples include propylene (C3H6), ethylene (C2H4), acetylene (C2H2), and other hydrocarbon gases mentioned above. One or more of these can be used as the third gas.

[0102] In addition to hydrocarbon gases, amine gases such as triethylamine ((C2H5)3N, abbreviated as TEA) and diethylamine ((C2H5)2NH, abbreviated as DEA) can also be used as the third gas. More than one of these gases can be used as the third gas.

[0103] In addition to the above, alkylsilanes such as trimethylsilane (SiH(CH3)3, abbreviated as TMS), dimethylsilane (SiH2(CH3)2, abbreviated as DMS), triethylsilane (SiH(C2H5)3, abbreviated as TES), and diethylsilane (SiH2(C2H5)2, abbreviated as DES) can also be used as the third gas. One or more of these can be used as the third gas.

[0104] [Step b]

[0105] In step b, a second gas is supplied to the wafer 200 in the processing chamber 201, that is, to the first layer on the wafer 200 on which C is adsorbed (or also referred to as the first layer containing C or the first layer containing C formed on the surface).

[0106] Specifically, valve 243d is opened, allowing the second gas to flow into gas supply pipe 232a. The flow rate of the second gas is regulated by MFC 241d, and it is supplied into processing chamber 201 via nozzle 249a and discharged from exhaust port 231a. At this time, the second gas is supplied to wafer 200 from the side (second gas supply). Meanwhile, valves 243e to 243g are kept open, and inactive gases are supplied into processing chamber 201 via nozzles 249a to 249c, respectively.

[0107] The processing conditions for supplying the second gas in this step are exemplified below:

[0108] Processing pressure: 20–133 Pa, preferably 40–70 Pa.

[0109] The second gas supply flow rate is 0.01–1.5 slm, preferably 0.1–0.8 slm.

[0110] Second gas supply time: 6 to 30 seconds, preferably 10 to 20 seconds.

[0111] The other processing conditions are the same as those when the first gas is supplied in step a.

[0112] By supplying a chlorosilane-based gas with a molecular structure different from the first gas as a second gas to the wafer 200 under the above processing conditions, a Si-containing layer is mainly formed on the first layer adsorbed with C as a second layer. The second layer is mainly formed by the deposition of Si onto the first layer adsorbed with C caused by the thermal decomposition of the chlorosilane-based gas.

[0113] More specifically, in this step, the processing temperature is set to a temperature above, or higher than, the temperature at which the second gas, such as a chlorosilane-based gas, undergoes thermal decomposition (gas-phase decomposition) when it exists alone in the processing chamber 201. As a result, most of the molecular structure of the second gas is thermally decomposed, forming a Si-containing layer with multiple Si stacks on top of the first layer containing adsorbed C, as the second layer.

[0114] If the processing temperature is below 450°C, the second gas is difficult to thermally decompose, sometimes making it difficult to form a second layer. By setting the processing temperature to 450°C or higher, the second gas is thermally decomposed, allowing a layer, for example, composed of multiple Si layers, to be formed on the first layer containing adsorbed C. This increases the film formation rate of the SiCN film. By setting the processing temperature to 650°C or higher, the second gas is thermally decomposed more fully, for example, allowing for more complete formation of a layer composed of multiple Si layers. This further increases the film formation rate of the SiCN film.

[0115] If the processing temperature exceeds 750°C, excessive thermal decomposition of the second gas occurs, sometimes making it difficult to form a second layer. By keeping the processing temperature below 750°C, excessive thermal decomposition of the second gas can be suppressed, allowing the second layer to form. By setting the processing temperature below 700°C, excessive thermal decomposition of the second gas can be suppressed more fully, resulting in more complete formation of the second layer.

[0116] As described above, defects in the layer are formed by carbon adsorption onto the first layer. Therefore, as will be explained later, a large number of defects will be formed in the first layer portion where the carbon is adsorbed during the final formation of the SiCN film.

[0117] If the thickness of the layer formed on wafer 200 through steps a to c exceeds several atomic layers, the modification effect in step d described later may not be able to extend to the entire Si-containing layer. Therefore, the thickness of the second layer is preferably approximately several atomic layers in total with the thickness of the layers formed through steps a and c.

[0118] Furthermore, in this method, the processing temperatures in steps a through c are substantially the same. Therefore, there is no need for temperature changes in the wafer 200 between steps a and c, i.e., no temperature changes are required within the processing chamber 201. Thus, the standby time before the wafer 200 temperature stabilizes between steps is unnecessary, thereby improving the productivity of the film deposition process.

[0119] Furthermore, in order to prevent (i.e. suppress) the thermal decomposition of the first gas in step a and to promote (i.e. promote) the thermal decomposition of the second gas in step b, for example, in step a, it is preferable to use a gas with a thermal decomposition temperature higher than that of the second gas as the first gas.

[0120] After the second layer is formed on wafer 200, valve 243d is closed to stop the supply of the second gas to the processing chamber 201. Then, through the same processing process and conditions as the purging described above, the gaseous substances remaining in the processing chamber 201 are removed from the processing chamber 201 (purging). It should be noted that the processing temperature during purging in this step is preferably set to the same temperature as the processing temperature when the second gas is supplied.

[0121] As a second gas, for example, a silane-based gas containing Si, which is the main element constituting the film formed on wafer 200, and whose molecular structure is different from that of the first gas can be used.

[0122] As the second gas, inorganic chlorosilane feedstock gases such as hexachlorosilane (Si2Cl6, abbreviated as HCDS) and octachlorotrisilane (Si3Cl8, abbreviated as OCTS) can be used. These gases can be considered feedstock gases containing at least two Si atoms and having Si-Si bonds in one molecule. In addition to these gases, chlorosilane gases such as tetrachlorosilane (SiCl4, abbreviated as STC), hydride-based gases such as monosilane (SiH4, abbreviated as MS), aminosilane gases such as tris(dimethylamino)silane (SiN[(CH3)2]3H, abbreviated as 3DMAS), and bis(diethylamino)silane (SiH2[N(C2H5)2]2, abbreviated as BDEAS) can also be used. One or more of these can be used as the second gas. By using a halogen-free gas as the second gas, halogens can be prevented from mixing into the SiCN film ultimately formed on wafer 200.

[0123] Of these gases, the aforementioned gases and other silane-based gases containing Si-Si bonds are preferred as the second gas.

[0124] [Step d]

[0125] In step d, a fourth gas is supplied to the wafer 200 in the processing chamber 201.

[0126] Specifically, valve 243c is opened, allowing the fourth gas to flow into gas supply pipe 232c. The flow rate of the fourth gas is regulated by MFC 241c, and it is supplied into processing chamber 201 via nozzle 249c and discharged from exhaust port 231a. At this time, the fourth gas is supplied to wafer 200 from the side (fourth gas supply). Meanwhile, valves 243e to 243g are kept open, and inactive gases are supplied into processing chamber 201 via nozzles 249a to 249c, respectively.

[0127] The processing conditions for supplying the fourth gas in this step are exemplified below:

[0128] Processing pressure: 133–1330 Pa, preferably 650–950 Pa.

[0129] The fourth gas supply flow rate is 1.0–9 slm, preferably 3.0–7 slm.

[0130] The fourth gas supply time is 10 to 60 seconds, preferably 20 to 50 seconds.

[0131] The other processing conditions are the same as those when the first gas is supplied in step a.

[0132] By supplying a fourth gas containing nitrogen (N) to the wafer 200 under the aforementioned processing conditions, at least a portion of the first layer and at least a portion of the second layer can be modified (nitrided). As a result, a silicon carbonitride layer (SiCN layer) containing Si, C, and N is formed on the wafer 200, that is, a layer formed by stacking a first layer containing C nitrided and a second layer containing C or containing C at a concentration lower than that of the first layer.

[0133] After the SiCN layer is formed, valve 243c is closed to stop the supply of the fourth gas to the processing chamber 201. Then, through the same processing procedure and conditions as the purging described above, the gaseous substances remaining in the processing chamber 201 are removed from the processing chamber 201 (purging). It should be noted that the processing temperature during purging in this step is preferably set to the same temperature as the processing temperature when the fourth gas is supplied.

[0134] As a fourth gas, a nitrogen-containing (N) and hydrogen-containing (H) gas can be used as a nitriding gas (nitriding agent). The gas containing N and H is both a nitrogen-containing gas and a hydrogen-containing gas.

[0135] As the fourth gas, hydrogen nitride gases such as ammonia (NH3), diazepine (N2H2), hydrazine (N2H4), and N3H8 can be used. One or more of these gases can be used as the fourth gas.

[0136] In addition to the fourth gas, gases containing nitrogen (N), carbon (C), and hydrogen (H) can also be used. For example, amine gases and organic hydrazine gases can be used as gases containing N, C, and H. A gas containing N, C, and H is a gas containing N, a gas containing C, a gas containing H, and a gas containing both N and C.

[0137] Examples of fourth gases include: ethylamine (C2H5NH2, abbreviated as MEA), diethylamine ((C2H5)2NH, abbreviated as DEA), triethylamine ((C2H5)3N, abbreviated as TEA), etc.; methylamine (CH3NH2, abbreviated as MMA), dimethylamine ((CH3)2NH, abbreviated as DMA), trimethylamine ((CH3)3N, abbreviated as TMA), etc.; and organic hydrazine ((CH3)HN2H2, abbreviated as MMH), dimethylhydrazine ((CH3)2N2H2, abbreviated as DMH), trimethylhydrazine ((CH3)2N2(CH3)H, abbreviated as TMH), etc. One or more of these can be used as the fourth gas.

[0138] [Number of scheduled implementations]

[0139] By performing steps a through d a predetermined number of times (n times, where n is an integer greater than or equal to 1) at different times (i.e., asynchronously), thus, as Figure 7 As shown, on wafer 200, the SiCN layers formed in each cycle can be stacked in a predetermined number to form a SiCN film. More specifically, a SiCN film containing Si, N, and C as its components can be formed on wafer 200, and defects are formed in the film by adding C. In the SiCN film, the density of defects formed in the first nitrided layer is higher than the density of defects formed in the second nitrided layer. The above cycle is preferably repeated multiple times. That is, preferably, the thickness of the SiCN layer formed in each cycle is thinner than the desired film thickness, and the above cycle is repeated multiple times until the film thickness of the SiCN film formed by stacking SiCN layers reaches the desired film thickness.

[0140] By supplying the first to fourth gases to the wafer 200 under the above processing conditions, the concentration of C in the SiCN film can be made to be 5 atomic% or less. The concentration of C in the SiCN film is preferably 1 atomic% or more and 5 atomic% or less, more preferably 1.5 atomic% or more and 4 atomic% or less, and even more preferably 2 atomic% or more and 3 atomic% or less.

[0141] If the C concentration in the SiCN film exceeds 5 atomic%, although it increases the amount of defects formed in the SiCN film, it also leads to a decrease in film density and a reduction in the SiCN film's leak resistance. By keeping the C concentration in the SiCN film below 5 atomic%, this reduction in leak resistance can be avoided. By keeping the C concentration in the SiCN film below 4 atomic%, this reduction in leak resistance can be avoided even more effectively. By keeping the C concentration in the SiCN film below 3 atomic%, this reduction in leak resistance can be avoided even more effectively.

[0142] If the concentration of carbon (C) in the SiCN film is less than 1 atomic%, sufficient defects may not be formed, thus reducing the charge trapping properties of the SiCN film. By increasing the C concentration in the SiCN film to 1 atomic% or more, sufficient defects can be formed, improving the charge trapping properties. Increasing the C concentration in the SiCN film to 1.5 atomic% or more further enhances the charge trapping properties. Increasing the C concentration in the SiCN film to 2 atomic% or more further enhances the charge trapping properties.

[0143] (Post-purging and atmospheric pressure restoration)

[0144] After the film-forming process described above is completed, inert gases are supplied as purge gases into the treatment chamber 201 through nozzles 249a to 249c, and exhaust gases are discharged through exhaust port 231a. This purges the treatment chamber 201, removing residual gases and reaction byproducts (post-purge). Subsequently, the atmosphere in the treatment chamber 201 is replaced with an inert gas (inert gas replacement), and the pressure in the treatment chamber 201 is restored to atmospheric pressure (atmospheric pressure restoration).

[0145] (Wafer box unloading and wafer release)

[0146] Next, the sealing cap 219 is lowered by the wafer cassette lifter 115, opening the lower end of the manifold 209. Then, the processed wafer 200, supported by the wafer cassette 217, is moved from the lower end of the manifold 209 to the outside of the reaction tube 203 (wafer cassette unloading). After the wafer cassette is unloaded, the baffle 219s moves, and the lower opening of the manifold 209 is sealed by the baffle 219s via the O-ring 220c (baffle closing). After the processed wafer 200 is moved to the outside of the reaction tube 203, it is removed from the wafer cassette 217 (wafer release).

[0147] (3) The effect of this method

[0148] According to this method, one or more of the following effects can be obtained.

[0149] (a) By performing each step a to d in the order of steps a, c, b, d but not simultaneously, specifically by performing step c immediately after step a, it is possible to make the concentration of C in the first nitrided layer higher than the concentration of C in the second nitrided layer.

[0150] Furthermore, when the C concentration on the surface of the first layer and the surface of the second layer are the same, for example, measurements based on the Photo Luminescence (PL) method confirmed that the number of defects formed in the nitrided first layer is greater than the number of defects formed in the nitrided second layer. This is believed to be because the nitrided first layer tends to have a composition closer to its stoichiometric composition than the nitrided second layer, and therefore, the first layer is more susceptible to the effects of C adsorption compared to the second layer.

[0151] As described above, by performing step c immediately after step a, the adsorption of C on the first layer is prioritized over the adsorption of C on the second layer, thereby suppressing the overall C content in the SiCN film and enabling efficient defect formation in the SiCN film. As a result, the SiCN film can be made into a film with excellent leakage characteristics and excellent charge trapping characteristics.

[0152] (b) By making the density of defects formed in the first modified layer higher than the density of defects formed in the second modified layer, the overall C content in the SiCN film can be suppressed, and defects can be formed efficiently in the SiCN film. As a result, the SiCN film can be made into a film with excellent leakage characteristics and excellent charge trapping characteristics.

[0153] (c) By using a gas with a thermal decomposition temperature that is higher than that of the second gas as the first gas, it is possible to improve the step coverage characteristics, the uniformity of the in-plane film thickness of the SiCN film formed on the wafer 200, and the film formation rate of the SiCN film.

[0154] (d) By using a gas without Si-Si bonds as the first gas and a gas containing Si-Si bonds as the second gas, the step coverage characteristics and in-plane film thickness uniformity of the SiCN film formed on wafer 200 can be further improved, and the film formation rate of the SiCN film can be further improved.

[0155] (e) In step a, the processing temperature is set below the temperature of the first gas thermal decomposition, and in step b, the processing temperature is set above the temperature of the second gas thermal decomposition. This sufficiently improves the step coverage characteristics and in-plane film thickness uniformity of the SiCN film formed on wafer 200, and also sufficiently improves the SiCN film deposition rate. Furthermore, it is preferable that in step a, the processing temperature is set below the temperature of the first gas thermal decomposition, and in step b, the processing temperature is set above the temperature of the second gas thermal decomposition, thereby obtaining these effects more reliably.

[0156] (4) Variations

[0157] The film-forming process in this method can be modified as shown in the following variations. These variations can be combined arbitrarily. Unless otherwise specified, the processing procedures and conditions in each step of each variation can be the same as those in each step of the above-described film-forming process.

[0158] (Variation Example 1)

[0159] It can also be like Figure 5 Similar to the film-forming process shown below, steps a through d are performed non-simultaneously in the order of steps c, a, b, and d. Specifically, step c can also be performed before step a. Figure 5 In the diagram, the implementation periods of steps a, b, c, and d are represented as a, b, c, and d, respectively.

[0160] (Third gas → First gas → Second gas → Fourth gas) × n → SiCN

[0161] In variation example 1, the same effect as described above can also be obtained.

[0162] (Variation Example 2)

[0163] Alternatively, steps a through d can be performed non-simultaneously in the order of steps c, a, c, b, d, as shown in the film-forming process below. Specifically, step c can be performed immediately before step a or immediately after step a.

[0164] (Third gas → First gas → Third gas → Second gas → Fourth gas) × n → SiCN

[0165] In Modified Example 2, the adsorption amount of C into the first layer can be increased, thus enabling more efficient defect formation in the SiCN film.

[0166] (Variation Example 3)

[0167] In the above description, an example was given where the implementation period of step a does not overlap with the implementation period of step c, but this disclosure is not limited thereto. For example, step c can be started while the supply of the first gas continues in step a, and the supply of the second gas can begin, so that at least a portion of the implementation period of step a overlaps with at least a portion of the implementation period of step c. Therefore, in addition to the effects described above, the cycle time can be shortened and the productivity of the film-forming process can be improved.

[0168] In this variation, it is preferable that the implementation period of step c does not overlap with the implementation period of step b. That is, it is preferable to perform purging after performing step c, followed by step b. This allows for the suppression of particle generation based on the third gas.

[0169] In this modified example, it is preferable that the implementation period of step c does not overlap with the implementation period of step d. Therefore, in addition to the effects described above, it is also possible to suppress the generation of particles caused by the reaction between the third and fourth gases, thus preventing a decrease in the quality of the SiCN film.

[0170] (Variation Example 4)

[0171] It can also be like Figure 6 Similar to the film-forming process shown below, at least a portion of the execution period of step a overlaps with the execution period of step c, and steps a, b, and d are performed sequentially. Figure 6 In the diagram, the implementation periods of steps a, b, and d are represented as a, b, and d, respectively.

[0172] (First gas + Third gas → Second gas → Fourth gas) × n → SiCN

[0173] In variation 4, in addition to the effects mentioned above, the cycle time can be shortened and the productivity of the film-forming process can be improved.

[0174] (Variation Example 5)

[0175] Alternatively, as shown in the film-forming process below, at least a portion of the implementation period of step a may overlap with the implementation period of step c, and the steps a through d may be performed in the order of steps a, c, b, and d.

[0176] (First gas + Third gas → Third gas → Second gas → Fourth gas) × n → SiCN

[0177] In Modified Example 5, the amount of C adsorbed into the first layer can be increased, thus enabling more efficient defect formation in the SiCN film.

[0178] (Variation Example 6)

[0179] Alternatively, as shown in the film-forming process below, at least a portion of the implementation period of step a may overlap with the implementation period of step c, and the steps a through d may be performed in the order of steps c, a, b, and d.

[0180] (Third gas → First gas + Third gas → Second gas → Fourth gas) × n → SiCN

[0181] In Modified Example 6, the adsorption amount of C into the first layer can be increased, thus enabling more efficient defect formation in the SiCN film.

[0182] (Variation Example 7)

[0183] Alternatively, as shown in the film-forming process below, at least a portion of the implementation period of step a may overlap with the implementation period of step c, and each step of steps a to d may be performed in the order of steps c, a, c, b, d.

[0184] (Third gas → First gas + Third gas → Third gas → Second gas → Fourth gas) × n → SiCN

[0185] In Modified Example 7, the amount of C adsorbed into the first layer can be increased, thus enabling more efficient defect formation in the SiCN film.

[0186] <Other methods of this disclosure>

[0187] The foregoing has detailed the manner in which this disclosure is made. However, this disclosure is not limited to the manner described above, and various modifications can be made without departing from its spirit.

[0188] For example, the above-described method illustrates the use of a third gas containing C as a predetermined element. However, this disclosure is not limited to this; for example, a third gas containing boron (B) as a predetermined element may also be used.

[0189] In this case, as a third gas, for example, monoborane (BH3), diborane (B2H6), or tetraborane (B4H) can be used. 10 Boron hydride gases, such as hydride-based gases, can be used as a third gas. One or more of these gases may be used.

[0190] In addition to boron hydride-based gases, boron chloride-based gases such as boron trichloride (BCl3) and diboron tetrachloride (B2Cl4) can also be used as the third gas. More than one of these can be used. It should be noted that, considering the ability to achieve a lower processing temperature, boron chloride-based gases are preferred over boron hydride-based gases as the third gas.

[0191] When using a gas containing boron as the third gas, a silicon boron nitride film (SiBN film) containing Si, N, and B can be formed on wafer 200. By adding boron to the film, defects (crystal defects) that trap charges can be formed in the film. In this case, the same effect as described above can be obtained.

[0192] In the above-described method, examples of using either a third gas containing C or a third gas containing B have been described. However, this disclosure is not limited thereto. For example, both a third gas containing C and a third gas containing B may be supplied. It should be noted that one of these two different third gases (e.g., the third gas containing B) may also be specifically referred to as a fifth gas containing a second predetermined element.

[0193] Specifically, a third gas containing C (a third gas containing a predetermined element) and a third gas containing B (a fifth gas containing a second predetermined element) can be supplied simultaneously.

[0194] Alternatively, a third gas containing C and a third gas containing B can be supplied continuously. In this case, the supply of the third gas of the other party can begin immediately after the supply of the third gas of either party ends. Alternatively, the supply of the third gas of the other party can begin while the supply of the third gas of either party is continuing, so that a portion of the supply period of the third gas of one party overlaps with a portion of the supply period of the third gas of the other party.

[0195] Alternatively, the third gas containing C and the third gas containing B can be supplied intermittently. For example, the supply of the third gas from the other party can begin after the supply of the third gas from either party has ended and a predetermined time has elapsed.

[0196] In these cases, the same effect as described above can be obtained. It should be noted that when both a third gas containing C and a third gas containing B are supplied simultaneously, the most defects can be formed in the membrane.

[0197] The formulations used in each process are preferably prepared separately according to the processing requirements and pre-stored in the storage device 121c via a telecommunication line and external storage device 123. Furthermore, when starting each process, the CPU 121a preferably selects a suitable formulation from the multiple formulations stored in the storage device 121c according to the processing requirements. This allows for the reproducible formation of films of various types, compositions, qualities, and thicknesses using a single substrate processing apparatus. Additionally, it reduces operator workload, avoids operational errors, and enables rapid initiation of each process.

[0198] The aforementioned formula is not limited to newly manufactured cases. For example, it can also be prepared by modifying an existing formula already installed in the substrate processing apparatus. In the case of changing the formula, the modified formula can also be installed in the substrate processing apparatus via a telecommunication line or a recording medium containing the formula. Alternatively, an existing formula already installed in the substrate processing apparatus can be directly modified by operating the input / output device 122 of an existing substrate processing apparatus.

[0199] In the above-described method, an example of forming a film using a batch-type substrate processing apparatus that processes multiple substrates at a time has been explained. This disclosure is not limited to the above-described method; for example, it can also be appropriately applied to the case of forming a film using a single-sheet substrate processing apparatus that processes one or more substrates at a time. Furthermore, in the above-described method, an example of forming a film using a substrate processing apparatus equipped with a hot-wall type furnace has been explained. This disclosure is not limited to the above-described method; it can also be appropriately applied to the case of forming a film using a substrate processing apparatus equipped with a cold-wall type furnace.

[0200] When using these substrate processing devices, each process can be performed under the same processing procedures and conditions as described above, and the same effects as described above can be obtained.

[0201] The above methods can be used in appropriate combinations. The processing procedures and conditions can be set to be the same as those in the methods described above. In the above methods, examples of steps not being performed simultaneously have been given; however, as long as it does not affect the membrane properties, periods in which the steps are performed simultaneously are also possible.

[0202] Example

[0203] Using the substrate processing apparatus described above, the following film formation process is performed to form a SiCN film on a wafer, thereby producing samples 1 to 4.

[0204] Sample 1: (First gas → Third gas → Second gas → Fourth gas) × n

[0205] Sample 2: (Third gas → First gas → Second gas → Fourth gas) × n

[0206] Sample 3: (First gas → Second gas → Fourth gas) × n

[0207] Sample 4: (First gas → Second gas → Third gas → Fourth gas) × n

[0208] STC gas is used as the first gas, HCDS gas is used as the second gas, C3H6 gas is used as the third gas, and NH3 gas is used as the fourth gas. The processing conditions are set to predetermined conditions within the range of processing conditions shown in the above-described steps.

[0209] After preparing samples 1 to 4, the C concentration in the SiCN film, the density of defects formed in the SiCN film, and the leakage resistance of the SiCN film were measured for samples 1 to 4 respectively.

[0210] The C concentration in the SiCN film was determined using photoelectron spectroscopy (XPS). Figure 8 As shown, the C concentrations (atomic C concentrations) in the SiCN films of samples 1-4 were 1.81 atomic%, 2.74 atomic%, 0 atomic%, and 1.09 atomic%, respectively. It was confirmed that the film of sample 3, which did not undergo step c, contained no C or substantially no C. It was confirmed that the C concentrations of samples 1, 2, and 4 were all good results of 5 atomic% or less, with sample 2 having the best value, being between 2 and 3 atomic%. Furthermore, it was confirmed that sample 1 had a value between 1.5 and 4 atomic%, which was the second best.

[0211] The density of defects formed in SiCN films is determined by measuring the total peak area of ​​the SiCN film using the PL method. A larger total peak area indicates a higher density of defects in the film. Figure 8 As shown, the total peak areas of samples 1-4 are 26261.9, 27719.2, 9733.4, and 21586.2, respectively. Therefore, sample 2 has the highest defect density, and sample 1 has the second highest defect density. Furthermore, the defect densities of samples 1 and 2 are higher than that of sample 4. This is attributed to the higher C concentrations in samples 1 and 2 compared to sample 4. This is because experiments have shown that STC gas absorbs C more readily than HCDS gas. Therefore, it is believed that if C is supplied immediately before or after the supply of STC gas, C is absorbed efficiently, resulting in a higher C concentration and consequently, more defects.

[0212] The leakage resistance of SiCN membranes is determined by measuring the leakage current (A / cm) flowing through the SiCN membrane when an electric field of 6 MV / cm is applied. 2 The results showed that sample 1 had the lowest leakage current and the best leakage resistance.

[0213] As can be seen from the above, the C concentration in the SiCN film of sample 1, the density of defects formed in the SiCN film, and the leakage resistance of the SiCN film are all suitable, while the C concentration in the SiCN film of sample 2 and the density of defects formed in the SiCN film are particularly good.

Claims

1. A substrate processing method comprising a step of forming a film containing silicon, a predetermined element, and nitrogen on a substrate by performing cycles including (a), (b), (c), and (d) a predetermined number of times. (a) A process of forming a first layer by supplying a first gas containing silicon and halogens but without Si-Si bonds to the substrate. (b) A process of forming a carbon-free second layer by supplying a second gas, which is an inorganic gas containing Si-Si bonds, to the substrate. (c) A process of supplying the substrate with a third gas containing carbon as the predetermined element, and (d) A process of supplying a fourth gas containing nitrogen to the substrate to modify the first layer and the second layer; As the predetermined element, an element capable of forming defects in the film is used. In the cycle, steps (a) through (d) are performed in any order of (a)(c)(b)(d), (c)(a)(b)(d), or (c)(a)(c)(b)(d). In (d), the density of the defects formed in the first nitrided layer is higher than the density of the defects formed in the second nitrided layer in (d).

2. The substrate processing method according to claim 1, wherein, At least a portion of the implementation period of (a) overlaps with at least a portion of the implementation period of (c).

3. The substrate processing method according to claim 2, wherein, The implementation period of (c) shall not overlap with the implementation period of (b).

4. The substrate processing method according to claim 2, wherein, The implementation period of (c) shall not overlap with the implementation period of (d).

5. The substrate processing method according to claim 1, wherein, In the cycle, each step (a) to (d) is performed in the order of (a), (c), (b), and (d).

6. The substrate processing method according to claim 1, wherein, In the cycle, each step (a) to (d) is performed in the order of (c)(a)(b)(d).

7. The substrate processing method according to claim 1, wherein, In the cycle, each step (a) to (d) is performed in the order of (c)(a)(c)(b)(d).

8. The substrate processing method according to claim 1, wherein, The third gas is selected from at least one gas chosen from the group consisting of hydrocarbon gases and amine gases.

9. The substrate processing method according to claim 1, wherein, The concentration of the predetermined element in the membrane is made to be less than 5 atomic percent.

10. The substrate processing method according to claim 9, wherein, The concentration of the predetermined element in the membrane is made to be 1 atom% or more.

11. The substrate processing method according to claim 1, wherein, The membrane is a charge trapping membrane for a non-volatile storage cell.

12. The substrate processing method according to claim 1, wherein, The cycle further includes (e) a step of supplying the substrate with a fifth gas containing a second predetermined element. At least a portion of the implementation period of (c) overlaps with at least a portion of the implementation period of (e).

13. The substrate processing method according to claim 1, wherein, The cycle further includes (e) a step of supplying the substrate with a fifth gas containing a second predetermined element. Make the implementation period of (c) continuous with the implementation period of (e).

14. The substrate processing method according to claim 1, wherein, The temperature of the substrate in (a) is either below the thermal decomposition temperature of the first gas when the first gas is present alone in the space where the substrate exists, or a temperature lower than the thermal decomposition temperature of the first gas. The temperature of the substrate in (b) is: a temperature above the thermal decomposition temperature of the second gas when the second gas exists alone in the space where the substrate exists, or a temperature higher than the thermal decomposition temperature of the second gas.

15. The substrate processing method according to claim 14, wherein, The temperature of the substrate in (a) and (b) is above 450°C and below 750°C.

16. A method for manufacturing a semiconductor device, comprising a step of forming a film containing silicon, a predetermined element, and nitrogen on a substrate by performing cycles including (a), (b), (c), and (d) a predetermined number of times. (a) A process of forming a first layer by supplying a first gas containing silicon and halogens but without Si-Si bonds to the substrate. (b) A process of forming a carbon-free second layer by supplying a second gas, which is an inorganic gas containing Si-Si bonds, to the substrate. (c) A process of supplying the substrate with a third gas containing carbon as the predetermined element, and (d) A process of supplying a fourth gas containing nitrogen to the substrate to modify the first layer and the second layer; As the predetermined element, an element capable of forming defects in the film is used. In the cycle, steps (a) through (d) are performed in any order of (a)(c)(b)(d), (c)(a)(b)(d), or (c)(a)(c)(b)(d). In (d), the density of the defects formed in the first nitrided layer is higher than the density of the defects formed in the second nitrided layer in (d).

17. A substrate processing apparatus comprising: A first gas supply system supplies a first gas containing silicon and halogens but without Si-Si bonds to the substrate. The second gas supply system supplies the substrate with a second gas, which is an inorganic gas containing Si-Si bonds. A third gas supply system supplies the substrate with a third gas containing carbon, a predetermined element capable of forming defects in the film. A fourth gas supply system supplies a fourth gas containing nitrogen to the substrate, and The control unit is configured to control the first gas supply system, the second gas supply system, the third gas supply system, and the fourth gas supply system, such that a process of forming a film containing silicon, the predetermined element, and nitrogen on the substrate is performed by performing a predetermined number of cycles. The cycle includes (a) a process of supplying the first gas to the substrate to form a first layer, (b) a process of supplying the second gas to the substrate to form a carbon-free second layer, (c) a process of supplying the third gas to the substrate, and (d) a process of supplying the fourth gas to the substrate to modify the first and second layers. In the cycle, each of the processes (a) to (d) is performed in any order of (a)(c)(b)(d), (c)(a)(b)(d), or (c)(a)(c)(b)(d). In (d), the density of defects formed in the layer formed by nitriding the first layer is higher than the density of defects formed in the layer formed by nitriding the second layer in (d).

18. A computer-readable recording medium having a program recorded thereon that causes a substrate processing apparatus to perform the following processes via a computer: The process of forming a film containing silicon, a predetermined element, and nitrogen on a substrate by performing cycles including (a), (b), (c), and (d) a predetermined number of times. (a) A process of forming a first layer by supplying a first gas containing silicon and halogens but without Si-Si bonds to the substrate. (b) A process of forming a carbon-free second layer by supplying a second gas, which is an inorganic gas containing Si-Si bonds, to the substrate. (c) A process of supplying the substrate with a third gas containing carbon, which is the predetermined element, capable of forming defects in the film. (d) The process of supplying a fourth gas containing nitrogen to the substrate to modify the first layer and the second layer; In the cycle, processes (a) through (d) are performed in any order of (a)(c)(b)(d), (c)(a)(b)(d), or (c)(a)(c)(b)(d), wherein the density of the defects formed in the first nitrided layer in (d) is higher than the density of the defects formed in the second nitrided layer in (d).

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