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

Abstract

To provide a technology that can improve charge trap characteristics by controlling the amount of Si-Si-Si bonds (Si substitution) and the amount of Si-Si bonds in the film formed on the substrate.SOLUTION: It has (a) a step for supplying a substrate with a degradable process gas containing silicon to form a layer containing Si-Si-Si bonds on the substrate; and (b) a step for processing to dissociate Si-Si-Si bonds by supplying reaction gas to the substrate.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] One of the manufacturing processes for semiconductor devices is a process for forming an insulating film such as a silicon oxide film (SiO2) or a silicon nitride film (Si3N4) on a substrate (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-153795 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique capable of improving charge trap characteristics by controlling the amount of Si-Si-Si bonds (Si substitution amount) and the amount of Si-Si bonds in a film formed on a substrate. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, there is provided a technique comprising the steps of: (a) supplying a decomposable process gas containing silicon to a substrate to form a layer containing Si-Si-Si bonds on the substrate; and (b) supplying a reactive gas to the substrate to dissociate the Si-Si-Si bonds. Effect of the Invention

[0006] The present disclosure makes it possible to improve charge trap characteristics by controlling the amount of Si-Si-Si bonds (Si substitution amount) and the amount of Si-Si bonds in a film formed on a substrate. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic configuration diagram showing a substrate processing apparatus used in a substrate processing method according to an embodiment of the present disclosure. [Diagram 2] 2 is a cross-sectional view taken along line AA in FIG. 1, showing a substrate processing apparatus used in a substrate processing method according to an embodiment of the present disclosure. [Diagram 3] 1 is a block diagram for explaining a controller provided in a substrate processing apparatus used in a substrate processing method according to an embodiment of the present disclosure. [Figure 4] 1 is a diagram showing a flow of a substrate processing method (semiconductor manufacturing method) according to one embodiment of the present disclosure. [Diagram 5] FIG. 2 is a schematic diagram showing a Si-substituted and N-deficient structure according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present disclosure will be described in detail below. The present disclosure is not limited to the following embodiments, which may be modified as appropriate within the scope of the present disclosure.

[0009] In the present disclosure, a numerical range indicated using "~" indicates a range that includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in the present disclosure. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0010] In the present disclosure, the term "step" encompasses not only independent steps, but also steps that cannot be clearly distinguished from other steps as long as a desired purpose is achieved.

[0011] Hereinafter, one embodiment of the present disclosure will be described mainly with reference to Figures 1 and 2. Note that all drawings used in the following description are schematic, and the dimensional relationships, ratios, etc. of each element on the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships, ratios, etc. of each element between multiple drawings do not necessarily match.

[0012] <Substrate processing equipment> As shown in Fig. 1, the substrate processing apparatus 100 has a processing furnace 202. A heater 207 is disposed in the processing furnace 202 as a temperature control unit. The heater 207 has a cylindrical shape and is installed vertically by being supported by a holding plate. The heater 207 also functions as an activation mechanism (excitation unit) that activates (excites) gas by heat.

[0013] A reaction tube 203 constituting a reaction vessel (processing vessel) is disposed inside the heater 207 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 in a cylindrical shape with a closed upper end and an open lower end. A manifold 209 is disposed below the reaction tube 203 and concentrically with the reaction tube 203. The manifold 209 is made of a metal such as stainless steel (SUS) and is formed in a cylindrical shape with open upper and lower ends. The upper end of the manifold 209 is engaged with the lower end of the reaction tube 203 and is configured to support the reaction tube 203 . An O-ring 220a serving as a seal member is provided between the manifold 209 and the reaction tube 203. The manifold 209 is supported on a heater base, so that the reaction tube 203 is installed vertically. A processing vessel (reaction vessel) is mainly constituted by the reaction tube 203 and the manifold 209. A processing chamber 201 is formed in a cylindrical hollow portion of the processing vessel. The processing chamber 201 is configured to be capable of accommodating a plurality of wafers 200 as substrates. Processing of the wafers 200 is performed in this processing chamber 201.

[0014] Nozzles 249a and 249b extending in the vertical direction are provided in the processing chamber 201 so as to penetrate the side wall of the manifold 209. Gas supply pipes 232a and 232b are connected to the nozzles 249a and 249b, respectively. In this manner, the reaction tube 203 is provided with two nozzles 249a and 249b and two gas supply pipes 232a and 232b, and is configured to be able to supply a plurality of types of gas (two types in this case) into the processing chamber 201.

[0015] Gas supply pipe 232a is provided with mass flow controller (MFC) 241a, which is a flow rate controller (flow rate control section), valve 243a, which is an on-off valve, reservoir (gas reservoir) 240a, which is configured to temporarily store gas, and valve 242a, in this order from the upstream side of the gas flow. In addition, an inert gas supply pipe 232c is connected to the downstream side of valve 243a of gas supply pipe 232a. In this inert gas supply pipe 232c, mass flow controller 241c, which is a flow rate controller (flow rate control section), and valve 243c, which is an on-off valve, are provided in this order from the upstream side of the gas flow.

[0016] The nozzle 249a described above is connected to the tip of the gas supply pipe 232a. The nozzle 249a is provided in an arc-shaped space between the inner wall of the reaction tube 203 and the wafers 200, along the inner wall of the reaction tube 203 from the lower part to the upper part, so as to rise upward in the loading direction of the wafers 200. The nozzle 249a is configured as an L-shaped long nozzle. Gas supply holes 250a for supplying gas are provided on the side of the nozzle 249a. The gas supply holes 250a open toward the center of the reaction tube 203. A plurality of gas supply holes 250a are provided from the lower part to the upper part of the reaction tube 203, each having the same opening area, and further provided at the same opening pitch.

[0017] The storage section 240a is configured as, for example, a gas tank or a spiral pipe having a larger gas capacity than a normal pipe. By opening and closing the valve 243a upstream of the storage section 240a and the valve 242a downstream of the storage section 240a, the gas supplied from the gas supply pipe 232a can be filled into the storage section 240a, and the gas filled in the storage section 240a can be supplied into the processing chamber 201. By closing the valve 242a and opening the valve 243a, the gas whose flow rate is adjusted by the MFC 241a can be filled into the storage section 240a. When a predetermined amount of gas is filled into the storage section 240a and the pressure in the storage section 240a reaches a predetermined pressure, the valve 243a is closed and the valve 242a is opened, so that the high-pressure gas filled in the storage section 240a can be supplied (flush-supplied) into the processing chamber 201 at once (in a short time) through the gas supply pipe 232a and the nozzle 249a. During flush supply, the valve 243a may be open. Furthermore, when supplying the processing gas into the processing chamber 201, the processing gas may be directly supplied into the processing chamber 201 without filling the storage portion 240a with the processing gas (non-flush supply).

[0018] A mass flow controller (MFC) 241b, which is a flow rate controller (flow rate control section), and a valve 243b, which is an on-off valve, are provided in the supply pipe 232b in this order from the upstream side of the gas flow. An inert gas supply pipe 232d is connected to the gas supply pipe 232b downstream of the valve 243b. The inert gas supply pipe 232d is provided with an MFC 241d and a valve 243d in this order from the upstream side of the gas flow.

[0019] A nozzle 249b is connected to the tip of the gas supply pipe 232b. The nozzle 249b is provided in a buffer chamber 237 which is a gas dispersion space.

[0020] 2, the buffer chamber 237 is provided in an arc-shaped space between the inner wall of the reaction tube 203 and the wafers 200, from the lower part to the upper part of the inner wall of the reaction tube 203, along the loading direction of the wafers 200. Gas supply holes 250c for supplying gas are provided at the end of the wall of the buffer chamber 237 adjacent to the wafers 200. The gas supply holes 250c open toward the center of the reaction tube 203. A plurality of gas supply holes 250c are provided from the lower part to the upper part of the reaction tube 203, each having the same opening area, and further provided at the same opening pitch.

[0021] The nozzle 249b is provided at the end opposite to the end where the gas supply holes 250c of the buffer chamber 237 are provided, along the inner wall of the reaction tube 203 from the lower part to the upper part, so as to rise upward in the loading direction of the wafers 200. The nozzle 249b is configured as an L-shaped long nozzle. Gas supply holes 250b for supplying gas are provided on the side of the nozzle 249b. The gas supply holes 250b open toward the center of the buffer chamber 237. Similar to the gas supply holes 250c of the buffer chamber 237, a plurality of gas supply holes 250b are provided from the lower part to the upper part of the reaction tube 203. When the pressure difference between the buffer chamber 237 and the processing chamber 201 is small, the opening area of ​​each of the multiple gas supply holes 250b may be the same from the upstream side (lower part) to the downstream side (upper part) with the same opening pitch. When the pressure difference is large, the opening area may be increased or the opening pitch may be decreased from the upstream side to the downstream side.

[0022] By adjusting the opening area and opening pitch of each of the gas supply holes 250b of the nozzle 249b from the upstream side to the downstream side as described above, gas is first ejected from each of the gas supply holes 250b at approximately the same flow rate, although there is a difference in flow velocity. Then, the gas ejected from each of the gas supply holes 250b is temporarily introduced into the buffer chamber 237, whereby the difference in gas flow velocity can be equalized. The gas ejected into the buffer chamber 237 from each of the gas supply holes 250b of the nozzle 249b has its particle speed reduced in the buffer chamber 237, and then ejected into the processing chamber 201 from the gas supply holes 250c of the buffer chamber 237. As a result, the gas ejected into the buffer chamber 237 from each of the gas supply holes 250b of the second nozzle 249b becomes a gas with a uniform flow rate and flow velocity when ejected into the processing chamber 201 from each of the gas supply holes 250c of the buffer chamber 237.

[0023] In this manner, in this embodiment, gas is transported via nozzles 249a, 249b and buffer chamber 237 arranged within a circular, vertically elongated space defined by the inner wall of reaction tube 203 and the ends of the multiple wafers 200 loaded thereon, i.e., within a cylindrical space.

[0024] Then, gas is ejected into the processing chamber 201 for the first time near the wafer 200 from the gas supply holes 250a-250c that are respectively opened in the nozzles 249a, 249b and the buffer chamber 237. The main flow of gas in the processing chamber 201 is parallel to the surface of the wafer 200, i.e., horizontal. Residual gas after reaction that has flowed over the surface of the wafer 200 flows toward the exhaust pipe 231, which will be described later. However, the flow direction of this residual gas is appropriately specified depending on the position of the exhaust port.

[0025] From the gas supply pipe 232a, (processing gas), for example, a gas containing silicon (Si) (silicon-containing gas), is supplied into the processing chamber 201 via the MFC 241a, the valve 243a, the storage unit 240a, the valve 242a, and the nozzle 249a.

[0026] From the gas supply pipe 232b, a (reactive gas), for example, a gas containing nitrogen (N) (nitrogen-containing gas), is supplied into the processing chamber 201 via the MFC 241b, the valve 243b, and the nozzle 249b. Note that the reactive gas is a substance whose molecular structure (chemical structure) is different from that of the processing gas.

[0027] From the gas supply pipes 232c and 232d, an inert gas is supplied into the processing chamber 201 via the MFCs 241c and 241d, the valves 243c and 243d, the gas supply pipes 232a and 232b, and the nozzles 249a and 249b. The inert gas acts as a purge gas, a carrier gas, a dilution gas, etc.

[0028] The gas supply pipe 232a, the MFC 241a, the valve 243a, the reservoir 240a, and the valve 242a constitute a process gas supply system. The gas supply pipe 232b, the MFC 241b, and the valve 243b constitute a reactive gas supply system. The gas supply pipes 232c and 232d, the MFCs 241c and 241d, and the valves 243c and 243d constitute an inert gas supply system.

[0029] As shown in FIG. 2, in the buffer chamber 237, two rod-shaped electrodes 269, 270 having an elongated structure are arranged from the lower part to the upper part of the reaction tube 203 along the stacking direction of the wafers 200. Each of the rod-shaped electrodes 269, 270 is provided in parallel with the nozzle 249b. Each of the rod-shaped electrodes 269, 270 is protected by being covered from the upper part to the lower part by an electrode protection tube 275. One of the rod-shaped electrodes 269, 270 is connected to a high-frequency power source 273 via a matching device 272, and the other is connected to earth, which is a reference potential. By applying high-frequency (RF) power from the high-frequency power source 273 between the rod-shaped electrodes 269, 270 via the matching device 272, plasma is generated in the plasma generation region 224 between the rod-shaped electrodes 269, 270. The rod-shaped electrodes 269, 270 and the electrode protection tube 275 mainly constitute a plasma source as a plasma generator (plasma generating unit). The matching box 272 and the high frequency power supply 273 may be considered to be included in the plasma source. The plasma source functions as an activation mechanism (excitation unit) that activates (excites) the gas into a plasma state, as described below. Note that, if the gas is not activated into a plasma state, the plasma generation unit does not need to be provided.

[0030] The electrode protection tube 275 has a structure that allows each of the rod-shaped electrodes 269, 270 to be inserted into the buffer chamber 237 while being isolated from the atmosphere in the buffer chamber 237. If the oxygen concentration inside the electrode protection tube 275 is approximately the same as the oxygen concentration in the outside air (atmosphere), the rod-shaped electrodes 269, 270 inserted into the electrode protection tube 275 will be oxidized by the heat from the heater 207. The oxygen concentration inside the electrode protection tube 275 can be reduced and the oxidation of the rod-shaped electrodes 269, 270 can be prevented by filling the inside of the electrode protection tube 275 with an inert gas such as nitrogen (N2) gas or by purging the inside of the electrode protection tube 275 with an inert gas such as nitrogen (N2) gas using an inert gas purge mechanism.

[0031] An exhaust pipe 231 for exhausting the atmosphere in the processing chamber 201 is connected to the reaction tube 203. One end of the exhaust pipe 231 is connected to an exhaust port at the lower end of the processing chamber 201. A vacuum pump 246 as an exhaust device is connected to the exhaust pipe 231 via a pressure sensor 245 as a pressure detector (pressure detection unit) for detecting the pressure in the processing chamber 201, an APC (Auto Pressure Controller) as an exhaust valve (pressure adjustment unit), and a valve 244. The APC valve 244 is a valve configured to be able to exhaust and stop exhausting the processing chamber 201 by opening and closing the valve while the vacuum pump 246 is in operation, and to adjust the pressure in the processing chamber 201 by adjusting the valve opening based on pressure information detected by the pressure sensor 245 while the vacuum pump 246 is in operation. An exhaust system is mainly configured by the exhaust pipe 231, the APC valve 244, and the pressure sensor 245. The vacuum pump 246 may be included in the exhaust system. The exhaust pipe 231 is not limited to being provided in the reaction tube 203, but may be provided in the manifold 209 similarly to the nozzles 249a and 294b.

[0032] Below the manifold 209, a seal cap 219 is provided as a furnace port cover capable of air-tightly closing the lower end opening of the manifold 209. The seal cap 219 is configured to abut against the lower end of the manifold 209 from below in the vertical direction. An O-ring 220b is provided on the upper surface of the seal cap 219 as a seal member that abuts against the lower end of the manifold 209. A rotation shaft 255 of the rotation mechanism 267 penetrates the seal cap 219 and is connected to a boat 217 described later. The rotation mechanism 267 is configured to rotate the wafers 200 by rotating the boat 217. The seal cap 219 is configured to be raised and lowered in the vertical direction by a boat elevator 115 as a lifting mechanism vertically installed outside the reaction tube 203. The boat elevator 115 is configured to lift and lower the seal cap 219 to load and unload the boat 217 into and out of the processing chamber 201. The boat elevator 115 is configured as a transfer device (transfer mechanism) that transfers the boat 217 and the wafers 200 supported by the boat 217 into and out of the processing chamber 201.

[0033] The boat 217 as a substrate holder is configured to support a plurality of wafers 200, for example, 25 to 200, in multiple stages in a horizontal position and aligned vertically with their centers aligned. The boat 217 is made of a heat-resistant material such as quartz or SiC. A heat insulating member 218 made of a heat-resistant material such as quartz or SiC is provided at the bottom of the boat 217, and is configured to prevent heat from the heater 207 from being transmitted to the seal cap 219.

[0034] A temperature sensor 263 serving as a temperature detector is provided in the processing chamber 201. The temperature distribution in the processing chamber 201 is configured to be a desired temperature distribution by adjusting the power supply to the heater 207 based on temperature information detected by the temperature sensor 263. The temperature sensor 263 is configured in an L-shape similar to the nozzles 249a and 249b, and is provided along the inner wall of the reaction tube 203.

[0035] 3, the controller 121, which is a control unit (control means), is configured as a computer including a CPU (Central Processing Unit) 121a, a RAM (Random Access Memory) 121b, a storage device 121c, and an I / O port 121d. The RAM 121b, the storage device 121c, and the I / O port 121d are configured to be able to exchange data with the CPU 121a via an internal bus 121e. An input / output device 122 configured as, for example, a touch panel, is connected to the controller 121.

[0036] The storage device 121c is composed of, for example, a flash memory, a HDD (Hard Disk Drive), etc. A control program for controlling the operation of the substrate processing apparatus, a process recipe describing the procedure and conditions of substrate processing such as film formation described later, etc. are readably stored in the storage device 121c. The RAM 121b is configured as a memory area (work area) in which the programs, data, etc. read by the CPU 121a are temporarily stored.

[0037] The I / O port 121d is connected to the above-mentioned MFCs 241a to 241d, valves 242a, 243a to 243d, storage section 240a, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotation mechanism 267, boat elevator 115, matching box 272, high frequency power supply 273, etc.

[0038] The CPU 121a is configured to read and execute a control program from the storage device 121c, and to read a process recipe from the storage device 121c in response to an input of an operation command from the input / output device 122, etc. The CPU 121a is configured to control the flow rate adjustment operation of various gases by the MFCs 241a to 241d, the opening and closing operations of the valves 242a, 243a to 243d, the storage operation of the processing gas by the storage unit 240a, the opening and closing operation of the APC valve 244 and the pressure adjustment operation by the APC valve 244 based on the pressure sensor 245, the start and stop of the vacuum pump 246, the temperature adjustment operation of the heater 207 based on the temperature sensor 263, the rotation and rotation speed adjustment operation of the boat 217 by the rotation mechanism 267, the raising and lowering operation of the boat 217 by the boat elevator 115, the impedance adjustment operation by the matching device 272, the power supply of the high frequency power source 273, etc., in accordance with the contents of the read process recipe. Here, the process recipe is a combination of procedures in a substrate processing process such as a film formation process described later that is executed by the controller 121 to obtain a predetermined result, and functions as a program.

[0039] The controller 121 may be configured as a general-purpose computer, not limited to a dedicated computer. For example, the controller 121 of this embodiment can be configured by preparing an external storage device (e.g., a semiconductor memory such as a USB memory or a memory card) 123 storing the above-mentioned program, and installing the program in a general-purpose computer using the external storage device 123. However, the means for supplying the program to the computer is not limited to supplying it via the external storage device 123. For example, the program may be supplied without going through the external storage device 123 by using a communication means such as the Internet or a dedicated line. The storage device 121c and the external storage device 123 are configured as computer-readable recording media. Hereinafter, these are collectively referred to simply as recording media. When the term recording medium is used in this disclosure, it may include only the storage device 121c alone, only the external storage device 123 alone, or both. The program may be provided to the computer using a communication means such as the Internet or a dedicated line, without using the external storage device 123.

[0040] <Substrate processing process> As one step in the manufacturing process of a semiconductor device (i.e., the substrate processing method according to the present disclosure), an example of a step of depositing a thin film on a wafer 200 will be described with reference to Fig. 4. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by a controller 121.

[0041] In the substrate processing method (semiconductor device manufacturing method) of the present disclosure, a layer containing Si-Si bonds and Si is formed on wafer 200 by carrying out the steps of (a) supplying a decomposable processing gas containing silicon to wafer 200 and forming a layer containing Si-Si-Si bonds on wafer 200, and (b) supplying a reactive gas to wafer 200 and dissociating the Si-Si-Si bonds.

[0042] It is presumed that the charge trap characteristics of the layer formed on the wafer 200 are improved by the above-mentioned substrate processing method (semiconductor device manufacturing method) because the amount of Si-Si bonds (N vacancies) contained in the layer can be easily controlled. That is, in the step (a), a layer containing Si-Si-Si bonds (Si substitutions) which are the source of N vacancies is formed. In the step (b), the amount of Si-Si bonds (N vacancies) can be controlled by supplying a reactive gas and adjusting the dissociation of the Si-Si-Si bonds.

[0043] In this disclosure, the term "wafer" may mean "the wafer itself" or "a laminate of a wafer and a predetermined layer, film, etc. formed on the surface." In this disclosure, the term "surface of a wafer" may mean "the surface of the wafer itself" or "the surface of a predetermined layer, film, etc. formed on the wafer." In this disclosure, the term "substrate" is synonymous with the term "wafer."

[0044] In the present disclosure, the term "Si-Si-Si bond" refers to three or more silicon atoms directly bonded to one silicon atom, as shown in FIG. In FIG. 5, each "X" independently represents one selected from the group consisting of a hydrogen atom, an alkyl group, an amine, a halogen atom, and a dangling bond (unbonded). In addition, in the present disclosure, the "Si-Si-Si bond" may be expressed as a "Si dB defect." In the present disclosure, the term "Si-Si bond" refers to one silicon atom directly bonded to another silicon atom, as shown in FIG. The "X" in FIG. 5 is the same as above. In addition, in the present disclosure, a "Si-Si bond" may be expressed as a "N defect (Si-H defect)". In the present disclosure, "-Si-" indicates that one silicon atom is not directly bonded to another silicon atom, and X is bonded to Si as shown in FIG.

[0045] In this disclosure, "processing temperature" refers to the temperature of the wafer 200 or the temperature inside the process chamber 201, and "processing pressure" refers to the pressure inside the process chamber 201. Additionally, "processing time" refers to the time that the process continues.

[0046] (Wafer charge and boat load) When a plurality of wafers 200 are loaded into the boat 217 (wafer charge), the boat 217 is lifted by the boat elevator 115 and carried into the processing chamber 201 (boat load). At this time, the seal cap 219 air-tightly seals the lower end of the reaction tube 203 via the O-ring 220b.

[0047] (Pressure regulation and temperature regulation) The inside of the processing chamber 201, i.e., the space in which the wafer 200 exists, is evacuated (reduced pressure exhaust) by the vacuum pump 246 so that the pressure (vacuum level) is reached. At this time, the pressure in the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 244 is feedback controlled (pressure adjustment) based on the measured pressure information. The vacuum pump 246 is kept in a constantly operating state at least until the processing of the wafer 200 is completed. The wafers 200 in the processing chamber 201 are heated by the heater 207 so as to reach a predetermined temperature. At this time, the amount of electricity supplied to the heater 207 is feedback-controlled (temperature adjustment) based on temperature information detected by the temperature sensor 263 so that the processing chamber 201 reaches the predetermined temperature. Heating of the processing chamber 201 by the heater 207 continues at least until the processing of the wafers 200 is completed.

[0048] (Film formation process) In the film formation process, the following steps 1 and 2 are carried out in this order.

[0049] [Process 1] This process includes (a) a step of supplying a decomposable processing gas containing silicon (hereinafter referred to as "processing gas") to the wafer 200 to form a layer having Si-Si-Si bonds, and may further include a step of removing (exhausting) residual gas in the processing chamber 201.

[0050] Specifically, the valve 243a is opened to allow the processing gas to flow into the gas supply pipe 232a. The processing gas is stored in the storage section 240a under flow rate control by the MFC 241a, and is flush-supplied from the gas supply hole 250a of the nozzle 249a into the processing chamber 201, and exhausted from the exhaust pipe 231. In this step, the processing gas may be directly supplied into the processing chamber 201 without being stored in the storage section 240a (non-flush supply). At this time, the valve 243c is simultaneously opened to allow an inert gas such as nitrogen (N2) gas to flow into the gas supply pipe 232c. The inert gas flowing through the gas supply pipe 232c has its flow rate adjusted by the MFC 241c. The flow-adjusted inert gas is exhausted from the exhaust pipe 231 while being supplied into the processing chamber 201 together with the processing gas.

[0051] When the Si-containing gas of the present disclosure is used as the processing gas, the processing conditions of this step are as follows: Treatment temperature: 500 to 1000°C, preferably 600 to 800°C, more preferably 650 to 750°C Treatment pressure: 1 to 2666 Pa, preferably 10 to 1333 Pa Processing gas supply flow rate: 1 to 2000 sccm, preferably 10 to 1000 sccm Treatment gas supply time: 1 to 120 seconds, preferably 1 to 60 seconds Examples are given below.

[0052] In this disclosure, the expression of a numerical range such as "500 to 1000°C" means that the lower limit and the upper limit are included in the range. Therefore, for example, "500 to 1000°C" means "500°C or more and 1000°C or less". The same applies to other numerical ranges. In this disclosure, the process temperature means the temperature of the wafer 200 or the temperature in the process chamber 201, and the process pressure means the pressure in the process chamber 201. In addition, when the supply flow rate includes 0 sccm, 0 sccm means that the gas is not supplied. These are the same in the following explanation.

[0053] The above step (a) is preferably carried out under conditions that suppress decomposition of the processing gas, thereby making it possible to reduce the amount of Si substitution and improve the charge trapping characteristics. Conditions for suppressing decomposition of the process gas include, for example, (1) a condition in which the temperature of the wafer 200 is below the temperature at which the process gas decomposes (preferably, a condition in which the temperature is lower than the temperature at which the process gas decomposes), (2) a condition in which the flow rate of the process gas is faster than the flow rate of the reaction gas described below, and (3) a condition in which the transit time of the process gas within the process chamber 201 (the space in which the wafer 200 is present, the space above the wafer 200) is shorter than the decomposition time of the process gas.

[0054] In the present disclosure, "decomposition of the process gas is suppressed" refers to suppression of dissociation (breakage) of Si-Si-Si bonds.

[0055] As for the above (1), for example, when the gas containing Si of the present disclosure is used as the processing gas (decomposition temperature: varies depending on the gas used, but is, for example, 300° C.), it is preferable that the temperature of the wafer 200 is lower than the decomposition temperature of the processing gas used. This improves the uniformity of the film formed on the wafer 200.

[0056] As for the above (2), for example, when the flow velocity of the process gas is set to 0.5 to 30 m / s, the flow velocity of the reaction gas is preferably set to 0.1 to 3.0 m / s, and more preferably to 0.5 to 1.5 m / s. The supply of the reactive gas is preferably performed by the above-mentioned flush supply. This can reduce the time that the reactive gas exists in the processing chamber 201, and can suppress the decomposition of the processing gas due to heat or the like. By suppressing the decomposition of the processing gas, the amount of Si replacement can be reduced. When processing is performed at such a flow rate, the temperature of the wafer 200 does not need to be lower than the decomposition temperature of the processing gas, and processing may be performed at a temperature equal to or higher than the decomposition temperature. The temperature of the wafer 200 higher than the decomposition temperature is, for example, in the range of 500 to 800°C, more preferably in the range of 600 to 800°C, and even more preferably in the range of 650 to 750°C. By setting the temperature in such a range, the reactivity of the reactive gas can be improved while suppressing the decomposition of the processing gas, and the characteristics of the film formed on the wafer 200 can be improved. Note that the temperature equal to or higher than the decomposition temperature includes a temperature equal to the decomposition temperature and a temperature higher than the decomposition temperature.

[0057] As for (3) above, for example, when the Si-containing gas of the present disclosure is used as the processing gas, the time for passing through the processing chamber 201 is preferably within a range of 0.01 to 0.5 seconds, and more preferably within a range of 0.05 to 0.1 seconds, which makes it possible to suppress decomposition of the processing gas and reduce the amount of Si replacement.

[0058] In the present disclosure, (a) is also preferably performed under conditions in which the process gas is decomposed, which can increase the amount of Si replacement and the amount of N vacancies caused by the supply of reactive gas. The condition for decomposing the process gas is, for example, that the pressure applied to the process gas is higher than the pressure applied to the reaction gas. Specifically, when the pressure applied to the reaction gas is 1 to 1333 Pa, the pressure applied to the process gas is 10 to 2666 Pa.

[0059] After the layer containing Si-Si-Si bonds is formed on the wafer 200, the valve 243a is closed to stop the supply of the processing gas. Then, the processing chamber 201 is evacuated to remove the processing gas remaining in the processing chamber 201, which is unreacted or has contributed to the formation of the layer containing Si-Si-Si bonds, from the processing chamber 201. At this time, the valve 243e is kept open to maintain the supply of the inert gas into the processing chamber 201. This enhances the effect of removing (purging) the processing gas remaining in the processing chamber 201, which is unreacted or has contributed to the formation of the layer having Si-Si-Si bonds, from the processing chamber 201.

[0060] When N2 gas is used as the inert gas, the processing conditions of this step are as follows: Inert gas supply flow rate: 100 to 1000 sccm, preferably 300 to 500 sccm Inert gas supply time: 1 to 60 seconds, preferably 2 to 20 seconds Other processing conditions are the same as those used when supplying the processing gas in this step.

[0061] The silicon-containing decomposable process gas of the present disclosure includes, for example, inorganic process gases and organic process gases.

[0062] Examples of inorganic processing gases include silicon-based gases containing halogens such as dichlorosilane (H2SiCl2) gas, hexachlorodisilane (Si2Cl6, abbreviated as HCDS) gas, and tetrachlorosilane (SiCl4) gas, as well as silicon-based gases that do not contain halogens such as SiH4, Si2H6, and Si3H8.

[0063] Examples of organic processing gases include aminosilane-based tetrakisdimethylaminosilane (Si(N(CH3)2))4) gas, trisdimethylaminosilane (Si(N(CH3)2))3H) gas, bisdiethylaminosilane (Si(N(C2H5)2)2H2) gas, and bistertiarybutylaminosilane (SiH2(NH(C4H9))2) gas. As the processing gas, one of these may be used alone, or two or more of them may be used in combination.

[0064] Among these, from the viewpoint of ease of forming a layer containing Si-Si-Si bonds, inorganic processing gases having Si-Si bonds, such as HCDS gas, Si2H6 gas, Si2I6 gas, and Si2Br6 gas, and organic processing gases having Si-Si bonds, such as SiH2(NH(C4H9))2 gas, are preferred.

[0065] By supplying the Si-containing gas of the present disclosure to the wafer 200 under the conditions of the present disclosure, a layer containing Si—Si—Si bonds can be formed on the wafer 200. The mechanism by which the layer containing Si-Si-Si bonds is formed is not clear, but is presumed to be as follows.

[0066] First, the Si-Si bonds of the gas molecules having Si-Si bonds supplied into the processing chamber 201 are broken. By breaking the Si-Si bonds, SiR X ("X" is an integer of 1 or more and represents a gas smaller than R contained in the raw material.) The generated SiR X is other SiR X and generates Si-Si-Si bonds. It is presumed that this Si-Si-Si bond is physically adsorbed and / or chemically adsorbed on the wafer 200 to form a layer containing Si-Si-Si bonds. Here, R is a ligand contained in the Si raw material of the present disclosure. For example, it is hydrogen (H), chlorine (Cl), an amino group, an alkylamino group, etc. When the process gas is, for example, HCDS, R is Cl, X is an integer from 1 to 3, and SiR X SiCl X It is.

[0067] As the inert gas, for example, rare gas such as nitrogen (N2) gas, argon (Ar) gas, helium (He) gas, neon (Ne) gas, xenon (Xe) gas, etc., can be used. The inert gas may be used alone or in combination of two or more kinds. This point is the same in each process described later.

[0068] [Process 2] After step 1, this process includes a step (b) of supplying a reactive gas to the wafer 200 to dissociate Si-Si-Si bonds in the layer containing Si-Si-Si bonds formed on the wafer 200. It is preferable to further include a step of removing (exhausting) residual gas in the process chamber 201. This makes it possible to form a layer containing Si and Si--Si bonds generated by dissociation of the Si--Si--Si bonds.

[0069] Specifically, the valve 243b is opened to allow the reactive gas to flow into the gas supply pipe 232b. The flow rate of the reactive gas is adjusted by the MFC 241b. The flow rate-adjusted reactive gas is supplied from the nozzle 249b into the buffer chamber 237. At this time, the reactive gas supplied into the buffer chamber 237 is excited into plasma by applying high frequency power between the first rod-shaped electrode 269 and the second rod-shaped electrode 270 from the high frequency power source 273 via the matching device 272, and is supplied as active species from the gas supply hole 250c into the processing chamber 201 while being exhausted from the gas exhaust pipe 231. At this time, the valve 243d is opened at the same time to allow the inert gas to flow into the inert gas supply pipe 232d. The inert gas is supplied into the processing chamber 201 together with the reactive gas while being exhausted from the gas exhaust pipe 231.

[0070] The processing conditions for this process are as follows: Treatment temperature: 500 to 1000°C, preferably 600 to 800°C, more preferably 650 to 750°C Treatment pressure: 1 to 4000 Pa, preferably 10 to 10000 Pa Reactive gas supply flow rate: 10 to 10,000 sccm, preferably 100 to 5,000 sccm Reactive gas supply time: 1 to 120 seconds, preferably 10 to 60 seconds High frequency power applied between rod electrodes: 0 to 1000 W Examples are given below.

[0071] Furthermore, it is also possible to thermally activate the reactive gas without plasma excitation when the reactive gas is supplied, by appropriately adjusting the APC valve 244 to set the pressure inside the processing chamber 201 to within a range of, for example, 50 to 3000 Pa. Note that supplying the reactive gas after activating it with heat can cause a softer reaction, and the nitridation described below can be performed softly. Note that when the reactive gas is not plasma excited, it is not necessary to provide a configuration for generating plasma in the substrate processing apparatus.

[0072] Thereafter, the valve 243b of the supply pipe 232b is closed to stop the supply of the reactive gas. At this time, the APC valve 244 of the gas exhaust pipe 231 is left open, and the inside of the processing chamber 201 is evacuated by the vacuum pump 246 to remove the reactive gas remaining in the processing chamber 201 from the inside of the processing chamber 201. Note that, at this time, the valve 243d is left open to maintain the supply of the inert gas into the processing chamber 201. This enhances the effect of removing (purging) the reactive gas remaining in the processing chamber 201 from the inside of the processing chamber 201.

[0073] When N2 gas is used as the inert gas, the processing conditions of this step are as follows: Inert gas supply flow rate: 100 to 1000 sccm, preferably 300 to 500 sccm Inert gas supply time: 1 to 60 seconds, preferably 2 to 20 seconds Examples are given below.

[0074] The reactive gas of the present disclosure may be, for example, a gas containing nitrogen (N) and hydrogen (H). Instead of the gas containing N and H, a gas containing N and deuterium (D) may be used. Examples of these gases include N2 gas + H2 gas; and hydrogen nitride gases such as ammonia (NH3) gas, diazene (N2H2) gas, hydrazine (N2H4) gas, N3H8 gas, and ND3 gas. These reactive gases may be used alone or in combination of two or more.

[0075] In this disclosure, the description of two gases together, such as "N2 gas + H2 gas", means a mixed gas of H2 gas and N2 gas. When supplying a mixed gas, the two gases may be mixed (premixed) in a supply pipe and then supplied into the processing chamber 201, or the two gases may be separately supplied into the processing chamber 201 from different supply pipes and mixed (postmixed) in the processing chamber 201.

[0076] Among these, from the viewpoint of increasing the amount of N vacancies, it is preferable to use hydrogen nitride gases such as N2 gas + H2 gas; NH3 gas, N2H2 gas, N2H4 gas, N3H8 gas, and ND3 gas.

[0077] A layer containing Si-Si bonds and Si is formed by supplying the reactive gas of the present disclosure to the wafer 200. In addition, Si and Si in the Si-Si bonds in the layer are partially reacted with the reactive gas and nitrided, forming a silicon nitride layer (SiN layer). The mechanism by which the layer containing Si--Si bonds and Si is formed is not clear, but is presumed to be as follows.

[0078] It is presumed that nitrogen atoms in the reaction gas penetrate between the Si-Si-Si bonds in the layer having Si-Si-Si bonds formed in step (a), and as a result, the Si-Si-Si bonds are dissociated into Si-Si bonds and Si, and the layer is modified to include Si-Si bonds and Si.

[0079] It is preferable that the Si in the Si-Si bond dissociated into a Si-Si bond and Si by the reaction gas is bonded to a nitrogen element. It is preferable that Si is bonded to a nitrogen element and also to another ligand.

[0080] In particular, nitrogen is preferable as the element that bonds Si and Si in the Si-Si bond. This allows the Si-Si bond formed on the wafer 200 and at least a part of the layer containing Si to be modified (nitrided) to form a SiN layer. In addition, the amount of N vacancies can be increased, and the charge trapping characteristics can be improved. The other ligands are each independently at least one of a hydrogen atom, an alkyl group, an amine, a halogen atom, and a dangling bond (unbonded), etc. The other ligands may include elements contained in the source gas molecules, ligands contained in the source gas molecules, and dangling bonds that are not bonded to these.

[0081] (Implementation at specified times) A cycle including the above-mentioned steps 1 and 2 can be performed a predetermined number of times (n times, where n is an integer of 1 or 2 or more). From the viewpoint of easily adjusting the refractive index, thickness, and / or composition of the layer formed on the surface of the wafer 200, it is preferable to perform the above-mentioned cycle multiple times.

[0082] When a cycle including steps 1 and 2 is performed a predetermined number of times, the supply conditions of the process gas and the reaction gas are preferably set based on the refractive index (RI) of the layer and the amount of Si-Si-Si bonds in the layer. Furthermore, when a cycle including steps 1 and 2 is performed a predetermined number of times, it is more preferable to set the supply conditions of the process gas and the reaction gas based on the RI of the layer, the amount of Si-Si-Si bonds in the layer, and the amount of Si-S bonds (amount of N vacancies) in the layer, which makes it easy to control the charge trap characteristics.

[0083] When setting the supply conditions of the process gas and the reaction gas, the RI of the layer formed on the surface of the wafer 200 is preferably 2.0 to 2.10, and more preferably 2.02 to 2.07. By setting the RI of the layer to 2.0 to 2.10, the required characteristics of the semiconductor device can be satisfied. If the RI of the layer is less than 2.0, the amount of N vacancies decreases, and the charge trapping properties deteriorate, whereas if the RI of the layer is more than 2.10, the amount of Si substitution increases, which may increase the leakage current, making it impossible to achieve the required semiconductor device properties. The RI of a layer can be measured, for example, using a device such as a spectroscopic ellipsometer.

[0084] In addition, it is preferable to set either or both of the supply conditions of the process gas and the supply conditions of the reaction gas based on the relationship between the Si substitution amount and the N vacancy amount of the layer formed on the surface of the wafer 200. Here, the relationship between the Si substitution amount and the N vacancy amount is a relationship represented by a graph in which the horizontal axis is the Si substitution amount and the vertical axis is the N vacancy amount. It is preferable that the Si substitution amount is 1E+18 or less and the N vacancy amount is 2.5E+18 or more. By setting it in this range, the required semiconductor device characteristics can be satisfied. More preferably, the supply conditions are set so that the Si substitution amount is 5E+17 or less and the N vacancy amount is 3.0E+18 or more. Even more preferably, the supply conditions are set so that the Si substitution amount is 1E+17 or less and the N vacancy amount is 3.5E+18 or more. If the Si substitution amount is more than 1E+18, the leakage current may increase, and the required semiconductor device characteristics may not be satisfied. If the N vacancy amount is less than 2.5E+18, the charge trap characteristics may decrease, and the required semiconductor device characteristics may not be satisfied. The smaller the amount of Si substitution, the more the leakage current can be reduced, but it is preferable to adjust it so that it is within the above-mentioned RI range.The larger the amount of N vacancy, the more the charge trap amount can be increased, but it is preferable to adjust it so that it is within the above-mentioned RI range. The amount of Si substitution and the amount of N vacancy can be calculated from the amount of dangling bonds contained in the layer, for example, by using an ESR (Electron Spin Resonance) method.

[0085] (Purge and return to atmospheric pressure) After the film formation on the wafer 200 is completed, an inert gas is supplied into the processing chamber 201 and exhausted from the exhaust pipe 231. The inert gas acts as a purge gas, and the processing chamber 201 is purged with the inert gas, and gas and reaction by-products remaining in the processing chamber 201 are removed from the processing chamber 201 (purging). Thereafter, the atmosphere in the processing chamber 201 is replaced with the inert gas (inert gas replacement), and the pressure in the processing chamber 201 is returned to normal pressure (return to atmospheric pressure).

[0086] (Boat unloading and wafer discharging) The seal cap 219 is lowered by the boat elevator 115 to open the bottom end of the reaction tube 203. Then, the processed wafers 200 are carried out of the reaction tube 203 while being supported by the boat 217 (boat unloading). After being carried out of the reaction tube 203, the processed wafers 200 are taken out of the boat 217 (wafer discharging).

[0087] <Other embodiments> Although the embodiments of the present disclosure have been specifically described above, the present disclosure is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit and scope of the present disclosure.

[0088] For example, as described above, a series of processes may be performed consecutively (in-situ) in the same processing chamber (processing vessel) 201. Also, at least one of the processes may be performed ex-situ in a different processing chamber (processing vessel). In either case, the same effects as those of the above-mentioned embodiment can be obtained. When the above-mentioned processes are performed in-situ, contamination of the wafer 200 and changes in the surface state of the wafer 200 that may occur when the wafer 200 is carried out of the processing chamber between processes or carried in from outside the processing chamber can be suppressed. Also, when these processes are performed in-situ, the transition time between processes can be shortened. On the other hand, when these processes are performed ex-situ, the processes can be performed in parallel in different processing chambers, thereby improving productivity.

[0089] In the above-mentioned embodiment, an example of forming a film using a batch-type substrate processing apparatus that processes multiple substrates at a time has been described. The present disclosure is not limited to the above-mentioned embodiment, and can be suitably applied to, for example, a case where a film is formed using a single-wafer type substrate processing apparatus that processes one or several substrates at a time. In addition, in the above-mentioned embodiment, an example of forming a film using a substrate processing apparatus having a hot-wall type processing furnace has been described. The present disclosure is not limited to the above-mentioned embodiment, and can be suitably applied to, for example, a case where a film is formed using a substrate processing apparatus having a cold-wall type processing furnace.

[0090] When using these substrate processing apparatuses, each process can be performed according to the same process procedures and under the same process conditions as in the above-described aspects and modifications, and the same effects as in the above-described aspects and modifications can be obtained. [Explanation of symbols]

[0091] 100 Substrate processing apparatus 200 wafers (substrates) 207 Heater 231 Exhaust pipe 232a, 232b Gas supply pipe 250a, 250c Gas supply holes

Claims

1. (a) supplying a decomposable process gas containing silicon to a substrate to form a layer containing Si—Si—Si bonds on the substrate; (b) supplying a reactive gas to the substrate to dissociate the Si—Si—Si bonds; A substrate processing method comprising the steps of:

2. 2. The substrate processing method according to claim 1, wherein the processing gas has a Si--Si bond.

3. In (b), the Si-Si-Si bond is dissociated into a Si-Si bond and a -Si-; 2. The substrate processing method according to claim 1, further comprising forming a layer containing the Si--Si bonds and the --Si--.

4. 4. The substrate processing method according to claim 1, wherein the reactive gas is a gas containing nitrogen and hydrogen elements.

5. the reactive gas is a gas containing a nitrogen element, In (b), Si in the Si-Si bond in the layer containing the Si-Si bond and the -Si- is bonded to a nitrogen element, The substrate processing method according to claim 3 , wherein the Si is bonded to the nitrogen element and another ligand.

6. 2. The method of claim 1, wherein (a) is performed under conditions that suppress decomposition of the process gas.

7. 2. The substrate processing method according to claim 1, wherein (a) is performed under conditions in which the temperature of the substrate is equal to or lower than the decomposition temperature of the processing gas.

8. 2. The substrate processing method according to claim 1, wherein (a) is performed under a condition in which a flow rate of the processing gas is faster than a flow rate of the reactive gas.

9. 2. The substrate processing method according to claim 1, wherein (a) is performed under conditions in which the time it takes for the process gas to pass through the space in which the substrate exists is shorter than the time it takes for the process gas to decompose.

10. 2. The method of claim 1, wherein (a) is carried out under conditions in which the process gas decomposes.

11. 2. The substrate processing method according to claim 1, wherein (a) is performed under a condition in which the pressure in the space in which the substrate exists is higher than the pressure in the space in which the substrate exists when (b) is performed.

12. 2. The substrate processing method according to claim 1, further comprising the steps of: (a) and (b) being repeated a predetermined number of times to form a layer containing Si on the substrate.

13. 13. The substrate processing method according to claim 12, wherein supply conditions for the process gas and the reactive gas are set based on a refractive index of the layer and an amount of Si--Si bonds in the layer.

14. 13. The substrate processing method according to claim 12, wherein supply conditions of the process gas and the reactive gas are set based on a refractive index of the layer, an amount of Si-Si-Si bonds in the layer, and an amount of Si-Si bonds in the layer.

15. 15. The substrate processing method according to claim 14, wherein supply conditions of the process gas and the reactive gas are set so that an amount of Si-Si-Si bonds in the layer is 1E+18 or less, and an amount of Si-Si bonds in the layer is 2.5E+18 or more.

16. 14. The substrate processing method according to claim 13, wherein the supply conditions of the process gas and the reaction gas are set so that the refractive index of the layer is in the range of 2.0 to 2.

10.

17. 14. The substrate processing method according to claim 13, wherein the supply conditions of the process gas and the reaction gas are set so that the refractive index of the layer is in the range of 2.02 to 2.

07.

18. (a) supplying a decomposable process gas containing silicon to a substrate to form a layer containing Si—Si—Si bonds on the substrate; (b) supplying a reactive gas to the substrate to dissociate the Si—Si—Si bonds; A method for manufacturing a semiconductor device having the above structure.

19. (a) supplying a decomposable process gas containing silicon to a substrate to form a layer containing Si—Si—Si bonds on the substrate; (b) supplying a reactive gas to the substrate to dissociate the Si—Si—Si bonds; A program for causing a computer to execute the above in a substrate processing apparatus.

20. a process gas supply system for supplying a decomposable process gas containing silicon to the substrate; a reactive gas supply system for supplying a reactive gas to the substrate; (a) supplying a decomposable process gas containing silicon to a substrate to form a layer containing Si—Si—Si bonds on the substrate; (b) supplying a reactive gas to the substrate to dissociate Si-Si-Si bonds; A control unit configured to be able to control A substrate processing apparatus comprising:

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