Gas supply method, method for manufacturing semiconductor device, program, gas supply system, and processing device

Abstract

Provided is a technology for supplying a raw material gas of a constant flow rate into a processing space. Provided is a technique comprising: (a) a step for supplying a raw material into a first tank; (b) a step for vaporizing the raw material; (c) a step for supplying, into a second tank, a raw material gas that has been obtained by vaporizing the raw material; and (d) a step for supplying the raw material gas from the second tank into a processing chamber. The time for the step (b) is set to a time during which the pressure in the first tank is maintained constant.

Description

Gas supply method, semiconductor device manufacturing method, program, gas supply system, and processing device

[0001] The present disclosure relates to a gas supply method, a semiconductor device manufacturing method, a program, a gas supply system, and a processing device.

[0002] As an example of a substrate processing apparatus, a semiconductor manufacturing apparatus for manufacturing semiconductor devices is known. Due to recent device miniaturization and other reasons, various processing gases, such as gas obtained by vaporizing a liquid or gas obtained by sublimating a solid, may be used as the processing gas. For example, in International Publication No. 2019 / 181603, the processing gas may be supplied by switching between multiple containers.

[0003] The present disclosure provides a technique for supplying a source gas at a constant flow rate to a processing space.

[0004] According to one aspect of the present disclosure, there is provided a technology comprising the steps of: (a) supplying a raw material to a first tank; (b) vaporizing the raw material; (c) supplying the gas obtained by vaporizing the raw material to a second tank; and (d) supplying the gas from the second tank to a processing chamber, wherein the time period in (b) is set to a time period during which the pressure in the first tank is maintained constant.

[0005] According to the present disclosure, a source gas can be supplied to a processing space at a constant flow rate.

[0006] FIG. 1 is a longitudinal sectional view showing a schematic configuration of a processing furnace of a substrate processing apparatus according to an embodiment of the present disclosure. FIG. 2 is a schematic transverse sectional view taken along line AA in FIG. 1. FIG. 3 is a schematic configuration diagram of a controller of a substrate processing apparatus according to an embodiment of the present disclosure, and is a block diagram showing a control system of the controller. FIG. 4 is a flowchart of a substrate processing step according to an embodiment of the present disclosure. FIG. 5 is a schematic view showing a configuration of a gas supply system of a substrate processing apparatus according to an embodiment of the present disclosure. FIG. 6 is a diagram showing a source gas supply sequence in a gas supply system according to an embodiment of the present disclosure. FIG. 7 is a diagram for explaining the effect of improving the source gas supply sequence according to an embodiment of the present disclosure. FIG. 8 is a diagram for explaining the effect of improving the source gas supply sequence according to an embodiment of the present disclosure. FIG. 9 is a diagram for explaining a source vaporization step of the source gas supply sequence according to an embodiment of the present disclosure.

[0007] The configuration of a substrate processing apparatus 100 according to one embodiment of the present disclosure will be described below with reference to Figures 1 and 2. Note that the drawings used in the following description are all schematic, and the dimensional relationships, ratios, etc. of elements shown in the drawings do not necessarily correspond to the actual ones. Furthermore, the dimensional relationships, ratios, etc. of elements between multiple drawings do not necessarily correspond to the actual ones.

[0008] (1) Configuration of the Substrate Processing Apparatus As shown in Fig. 1, the processing furnace 202 has a heater 207 as a heating system (temperature adjustment unit). The heater 207 has a cylindrical shape. The heater 207 also functions as an activation mechanism (excitation unit) that activates (excites) gas by heat.

[0009] A reaction tube 203 is disposed inside the heater 207 concentrically with the heater 207. The reaction tube 203 is made of, for example, quartz (SiO ２The reaction tube 203 is made of a heat-resistant material such as silicon carbide (SiC) or silicon dioxide (SiO2), and is cylindrically shaped with a closed top and an open bottom. A manifold 209 is disposed concentrically below the reaction tube 203. The manifold 209 is made of a metal such as stainless steel (SUS), and is cylindrically shaped with both an open top and a closed 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 serving as a sealing member is provided between the manifold 209 and the reaction tube 203. The reaction tube 203 is installed vertically, similar to the heater 207. The reaction tube 203 and the manifold 209 mainly constitute a processing vessel (reaction vessel). A processing chamber 201 serving as a processing space is formed in the cylindrical hollow portion of the processing vessel. The processing chamber 201 is configured to accommodate multiple wafers 200 as substrates.

[0010] Nozzles 249a and 249b are provided in the processing chamber 201 so as to penetrate the sidewall of the manifold 209. Gas supply pipes (piping) 232a and 232b are connected to the nozzles 249a and 249b, respectively. The nozzle 249a and the gas supply pipe 232a form a flow path through which not only a gas obtained by phase-changing a liquid or solid source material at room temperature into a gaseous state, but also a gas containing a gaseous source material at room temperature (hereinafter referred to as source gas) flows.

[0011] A raw material container 270 is connected to the gas supply pipe 232a via a valve 243e. Therefore, the gas supply pipe 232a is provided with, in this order from the upstream side, the raw material container 270, a valve 243e as an example of a first opening / closing unit, a vaporization container 280 as a first tank, a valve 243a, a mass flow controller (MFC) 241a as a flow rate controller, a valve 243g, a flash tank 282 as a second tank (hereinafter simply referred to as a tank), and a valve 243h.

[0012] Furthermore, a bypass pipe 233 that bypasses the valve 243e is provided in the gas supply pipe 232a. A valve 243f, which is an example of a second opening / closing unit, is provided in the bypass pipe 233. These components, including the valves 243a, 243e, 243f, 243g, and 243h, the gas supply pipe 232a, the bypass pipe 233, the vaporization vessel 280, the tank 282, and the MFC 241a, constitute a source gas supply system.

[0013] A gas supply pipe 232c for supplying an inert gas is connected to the gas supply pipe 232a so as to branch off from the gas supply pipe 232a. An MFC 241c and a valve 243c are provided in the gas supply pipe 232c in this order from the upstream side to form an inert gas supply system. Note that this inert gas supply system may be considered to be included in the source gas supply system.

[0014] In addition, the gas supply pipe 232b is provided with, in order from the upstream side, an MFC 241b and a valve 243b which is an on-off valve. Furthermore, a gas supply pipe 232d which supplies an inert gas is connected to the gas supply pipe 232b so as to branch off from the gas supply pipe 232b. A reactive gas supply system is mainly configured by the gas supply pipe 232b, the MFC 241b, and the valve 243b. An inert gas supply system is mainly configured by the gas supply pipe 232d, the MFC 241d, and the valve 243d. This inert gas supply system may be considered to be included in the reactive gas supply system. The source gas supply system and the reactive gas supply system may be collectively referred to as the gas supply system, and the inert gas supply system may also be included in the gas supply system.

[0015] 2, the nozzles 249a and 249b are respectively provided in an annular space in a plan view between the inner wall of the reaction tube 203 and the wafers 200, along the inner wall of the reaction tube 203 from the bottom to the top, rising upward in the stacking direction of the wafers 200. Gas supply holes 250a and 250b for supplying gas as a material are respectively provided on the side surfaces of the nozzles 249a and 249b. The gas supply holes 250a and 250b are each open toward the center of the reaction tube 203, allowing gas to be supplied toward the wafers 200. A plurality of gas supply holes 250a and 250b are provided from the bottom to the top of the reaction tube 203.

[0016] From the gas supply pipe 232a, a raw material is supplied from the raw material container 270 via the valve 243e or the valve 243f to the processing chamber 201 via the vaporization container 280, the valve 243a, the MFC 241a, the valve 243g, the tank 282, the valve 243h, and the nozzle 249a.

[0017] A reactive gas (processing gas) such as a nitrogen-containing gas that reacts with the source gas is supplied from the gas supply pipe 232b via the MFC 241b, the valve 243b, and the nozzle 249b to the processing chamber 201. A reducing gas can be used as the reactive gas.

[0018] Inert gas is supplied from the gas supply pipes 232c and 232d to the processing chamber 201 via MFCs 241c and 241d, valves 243c and 243d, gas supply pipes 232a and 232b, a valve 243h, and nozzles 249a and 249b, respectively.

[0019] The opening and closing operations of the valves 243a to 243h and the flow rate adjustment operations of the MFCs 241a to 241d are controlled by a controller 121, which will be described later. Hereinafter, the MFCs 241a to 241d may be collectively referred to as MFC 241, and the valves 243a to 243h may be collectively referred to as valves 243. The same applies to the other components.

[0020] The reaction tube 203 is provided with an exhaust pipe 231 for exhausting the atmosphere in the processing chamber 201. The exhaust pipe 231 is connected to a vacuum pump 246 serving as a vacuum exhaust device via a pressure sensor 245 serving as a pressure detector for detecting the pressure in the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 serving as a pressure regulator. The APC valve 244 opens and closes the valve while the vacuum pump 246 is operating, thereby evacuating and stopping the evacuation of the processing chamber 201. Furthermore, while the vacuum pump 246 is operating, the valve opening degree is adjusted based on pressure information detected by the pressure sensor 245, thereby adjusting the pressure in the processing chamber 201. The exhaust pipe 231, the APC valve 244, and the pressure sensor 245 mainly constitute an exhaust system. The vacuum pump 246 may also be considered to be included in the exhaust system.

[0021] A seal cap 219 serving as a lid capable of airtightly closing the lower end opening of the manifold 209 is provided below the manifold 209. The lid 219 is made of a metal such as SUS and is formed in a disk shape. An O-ring 220b serving as a sealing member that abuts against the lower end of the manifold 209 is provided on the upper surface of the lid 219. A rotation mechanism 267 for rotating the boat 217 (described later) is provided below the lid 219. The rotation mechanism 267 is configured to rotate the boat 217 to rotate the wafers 200. The lid 219 is configured to be raised and lowered vertically by a boat elevator 115 serving as a lifting mechanism installed outside the reaction tube 203. The lifting mechanism 115 is configured to raise and lower the lid 219 to load and unload the boat 217 into and out of the processing chamber 201. The lifting mechanism 115 is configured as a transfer device (transfer mechanism) that transfers the boat 217 , that is, the wafers 200 , into and out of the processing chamber 201 .

[0022] The boat 217, which serves as a substrate support, is configured to hold a plurality of wafers 200, for example, 25 to 200, arranged horizontally and with their centers aligned at intervals. The boat 217 is made of a heat-resistant material such as quartz or SiC. A thermal insulating plate 218, also made of a heat-resistant material such as quartz or SiC, is supported in multiple stages below the boat 217. Note that in this specification, a numerical range such as "25 to 200" means that the lower and upper limits are included in the range. Thus, for example, "25 to 200" means "25 to 200." The same applies to other numerical ranges.

[0023] A temperature sensor 263 serving as a temperature detector is installed along the inner wall of the reaction tube 203. By adjusting the power supply to the heater 207 based on the temperature information detected by the temperature sensor 263, the temperature of the processing chamber 201 can be distributed as desired.

[0024] (Source Container) The source container 270 may be a container for storing a liquid or solid source material, rather than simply a source gas container that is gaseous at room temperature. Here, a liquid source material is a source material that exists as a liquid at room temperature and pressure, and a solid source material is a source material that exists as a solid at room temperature and pressure.

[0025] (Vaporization Container) The vaporization container 280 serving as the vaporization unit is provided with a heating unit (not limited to a heater, any heat source will do) not shown. The controller 121 described below is configured to heat this heating unit to control the temperature to a temperature equal to or higher than the vaporization temperature if the raw material is liquid. If the raw material is solid, the controller 121 is configured to heat this heating unit to control the temperature to a temperature equal to or higher than the sublimation temperature of the raw material. Note that if the raw material is solid, the raw material container 270 and the vaporization container 280 may be configured as an integrated unit.

[0026] Furthermore, when the raw material is a liquid raw material, the vaporization container 280 is filled with a required predetermined amount of raw material from the raw material container 270. At this time, the controller 121, which will be described later, controls the opening and closing of valves 243e and 243f. When the raw material is a solid raw material, the raw material container 270 is not necessary, and the solid raw material is pre-filled in the vaporization container 280. At this time, the controller 121, which will be described later, vaporizes the liquid raw material or sublimes the solid raw material using a heater (not shown), thereby generating a required predetermined amount of raw material gas. Furthermore, an inert gas may be supplied into the vaporization container 280 as needed.

[0027] Next, the controller 121, which is the control unit (control means), will be described. As shown in Fig. 3, the controller 121, which is the 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, which is configured as, for example, a touch panel, is connected to the controller 121.

[0028] The storage device 121c includes, for example, a flash memory, a hard disk drive (HDD), etc. The storage device 121c readably stores a control program for controlling the operation of the substrate processing apparatus 100, a process recipe describing the procedures and conditions of the substrate processing described below, and the like. The process recipe is a combination of procedures for the substrate processing described below that are executed by the controller 121 to obtain a predetermined result, and functions as a program. Hereinafter, the process recipe, the control program, etc. are collectively referred to simply as a program (program product). The process recipe is also simply referred to as a recipe. In this specification, the term "program" may refer to a recipe alone, a control program alone, or both. The RAM 121b is configured as a memory area (work area) for temporarily storing programs, data, etc. read by the CPU 121a.

[0029] The I / O port 121d is connected to the above-mentioned MFC 241, valve 243, pressure sensor 245, APC valve 244, vacuum pump 246, heater 207, temperature sensor 263, rotation mechanism 267, boat elevator 115, and the like.

[0030] The CPU 121a is configured to read and execute a control program from the storage device 121c, and also to read a recipe from the storage device 121c in response to input of an operation command from the input / output device 122. The CPU 121a is configured to control, in accordance with the contents of the read recipe, the flow rate adjustment operation of various gases by the MFC 241, the opening and closing operation of the valve 243, 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 lifting and lowering operation of the boat 217 by the boat elevator 115, the execution of a source gas supply sequence described later, and the like.

[0031] The controller 121 can be configured by installing the above-described program stored in an external storage device 123 (e.g., a magnetic disk such as a hard disk, an optical disk such as a CD, or a semiconductor memory such as a USB memory) into a computer. The storage device 121c and the external storage device 123 are configured as computer-readable recording media on which the program is recorded. Hereinafter, these will be collectively referred to as recording media. When the term recording media is used in this specification, it may refer to only the storage device 121c alone, only the external storage device 123 alone, or both. Note that the program may be provided to the computer via a communication means such as the Internet or a dedicated line, without using the external storage device 123. Furthermore, the controller 121 is provided with a receiving unit 124 connected to the host device 75 via a network. The receiving unit 124 is capable of receiving information about other devices from the host device 75.

[0032] <Substrate Processing Method> Next, a substrate processing method using the substrate processing apparatus 100 according to an embodiment of the present disclosure will be described with reference to the flowchart of Fig. 4. Here, as an example of a semiconductor device manufacturing process, a cycle process in which a source gas (raw material gas) and a reactant gas (reaction gas) are alternately supplied to the processing chamber 201 will be described. In this embodiment, an example of forming a film on a wafer 200 will be described.

[0033] The term "wafer" used in this specification can refer to the wafer itself or to a laminate of the wafer and a predetermined layer or film formed on its surface. When described in this specification as "forming a predetermined film on a wafer," it can mean forming a predetermined film directly on the surface of the wafer itself, or forming a predetermined film on a film or the like formed on the wafer. When the term "substrate" is used in this specification, it is synonymous with the term "wafer."

[0034] In the process of this embodiment, a film is formed on the wafer 200 by performing a cycle of non-simultaneously a predetermined number of times (one or more times) of the following steps: a step of supplying a raw material gas to the wafer 200 in the processing chamber 201 (film formation process 1: step S3); a purge step of removing the raw material gas (residual gas) from the processing chamber 201 (film formation process 2: step S4); a step of supplying a reactive gas to the wafer 200 in the processing chamber 201 (film formation process 3: step S5); and a purge step of removing the reactive gas (residual gas) from the processing chamber 201 (film formation process 4: step S6).

[0035] First, as described above, the wafers 200 are loaded into the boat 217 and then loaded into the processing chamber 201 (step S1). After the boat 217 is loaded into the processing chamber 201, the pressure and temperature of the processing chamber 201 are adjusted (step S2). Next, four steps of film formation processes 1 to 4 are performed in sequence. Each step will be described in detail below.

[0036] (Film Forming Process 1) In film forming process 1, first, a source gas is supplied onto the surface of the wafer 200. Specifically, in the source gas supply system (source gas supply line), the valves 243a and 243g are opened and the valve 243h is closed, and the source gas, the flow rate of which is controlled by the MFC 241a, is stored in the tank 282, and by the time step S2 is completed, a predetermined amount of the source gas required for film formation is supplied to the tank 282. Then, in film forming process 1, the valves 243a and 243g are closed and the valve 243h is opened, and the source gas stored in the tank 282 is supplied to the processing chamber 201 all at once.

[0037] (Film Forming Process 2) Next, in Film Forming Process 2, the valve 243h of the source gas supply system is closed to stop the supply of the source gas. The APC valve 244 of the exhaust pipe 231 is left open, and the processing chamber 201 is evacuated by the vacuum pump 246 to a pressure below a predetermined value, thereby removing the remaining source gas from the processing chamber 201. If an inert gas such as N2 is supplied to the processing furnace 202 at this time, the effect of removing the remaining source gas is further enhanced.

[0038] (Film Forming Process 3) In film forming process 3, a reactive gas is flowed into the processing chamber 201. First, the valve 243b provided on the gas supply pipe 232b is opened, and a reactive gas whose flow rate is adjusted by the MFC 241b is supplied from the gas supply pipe 232d through the gas supply hole 250b of the nozzle 249b into the processing chamber 201 while being exhausted through the exhaust pipe 231. The supply of the reactive gas causes the film on the base film of the wafer 200 to react with the reactive gas, and a predetermined film is formed on the wafer 200.

[0039] (Film Formation Process 4) In film formation process 4, after a film is formed on the wafer 200, the valves 243b and 243d are closed, and the processing chamber 201 is evacuated to a vacuum using a vacuum pump 246 as an exhaust device, thereby removing the reaction gas remaining after contributing to the film formation. If an inert gas such as N2 is supplied to the processing chamber 201 at this time, the effect of removing the remaining reaction gas from the processing chamber 201 is further enhanced.

[0040] The above-described film formation steps 1 to 4 constitute one cycle, and in step S7, the cycle of film formation steps 1 to 4 is performed a predetermined number of times to form a film with a predetermined thickness on wafer 200. In this embodiment, film formation steps 1 to 4 are repeated multiple times.

[0041] After the above-described film formation process is completed, in step S8, the pressure in the processing chamber 201 is returned to normal pressure (atmospheric pressure). Specifically, an inert gas, such as N2 gas, is supplied to the processing chamber 201 and then exhausted. As a result, the processing chamber 201 is purged with the inert gas, and gases remaining in the processing chamber 201 are removed from the processing chamber 201 (inert gas purge). 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 (atmospheric pressure). Then, in step S9, the wafer 200 is unloaded from the processing chamber 201, thereby completing the substrate processing according to this embodiment.

[0042] Next, the configuration of the gas supply system according to this embodiment will be described with reference to FIG.

[0043] The gas supply system in this embodiment mainly includes a valve 243e, a pressure sensor 283, a vaporization container 280, a valve 243f, an MFC 241a as an example of a flow rate control unit, a tank 282, a pressure sensor 281, and a controller 121 as an example of a monitoring unit. The gas supply system in this embodiment may also include a source container 270, a gas supply pipe 232a, a bypass pipe 233 as an example of a bypass flow path, and valves 243a, 243g, and 243h.

[0044] The valve 243e is provided upstream of the gas supply pipe 232a and downstream of the source material container 270. This valve 243e is, for example, an on-off valve, and its opening and closing operation is controlled by the controller 121. Furthermore, the valve 243e is larger than the valve 243f in at least one of the flow path diameter, flow path cross-sectional area, and Cv value. Here, the Cv value is an intrinsic coefficient that indicates the ease of flow of a fluid, and is one of the capacity coefficients of a valve defined by the JIS standard (JIS B 0100). Hereinafter, in this specification, the Cv value may be simply referred to as the capacity coefficient.

[0045] The vaporization container 280 is provided downstream of the valve 243e of the gas supply pipe 232a. The vaporization container 280 has a function of temporarily storing the source gas flowing out from the source container 270. A pressure sensor 283 is provided between the source container 270 and the vaporization container 280, more specifically, between the valve 243e and the vaporization container 280. The pressure sensor 283 measures the pressure inside the vaporization container 280. Downstream of the vaporization container 280 on the gas supply pipe 232a, valves 243a and 243g are provided on either side of the MFC 241a. The valves 243a and 243g are, for example, on-off valves, and their opening and closing operations are controlled by the controller 121. Furthermore, a pressure sensor 281 is provided between the valve 243g of the gas supply pipe 232a and the tank 282. The pressure sensor 281 measures the pressure inside the tank 282. The pressure value inside the tank 282 measured by the pressure sensor 281 is transmitted to the controller 121. A pressure sensor (not shown) is provided in the gas supply pipe 232a downstream of the vaporization container 280 and upstream of the MFC 241a, and the controller 121 monitors the pressure so that it does not exceed the controllable pressure limit value of the MFC 241a.

[0046] Valve 243f is provided in bypass pipe 233 that bypasses valve 243e. Valve 243f is a control valve having a valve portion whose opening degree can be adjusted, and its opening and closing operation is controlled by controller 121. Specifically, the opening and closing operation of valve 243f, including its opening degree, is controlled by controller 121. Valves 243e and 243f are disposed between source material container 270 and vaporization container 280. As an example of valve 243f, the same valve as the control valve of MFC 241a may be used.

[0047] The MFC 241a is disposed between the valve 243a and the portion where the gas supply pipe 232a and the gas supply pipe 232c join. The MFC 241a can control the flow rate of the source gas under controllable pressure conditions. The source gas is supplied to the tank 282 while being controlled to a constant flow rate by the MFC 241a.

[0048] The controller 121 monitors the pressure values ​​received from the pressure sensors 281 and 283. Specifically, it monitors the pressure values ​​detected by the pressure sensors 281 and 283. In particular, when the pressure value detected by the pressure sensor 281 reaches a predetermined pressure (hereinafter, sometimes referred to as a target pressure) as a preset threshold, the controller 121 opens the valve 243h to supply the source gas stored in advance in the tank 282 to the processing chamber 201. The pressure value detected by the pressure sensor 283 will be described later.

[0049] Furthermore, the controller 121 controls the opening and closing operations of the valves 243 a and 243 g. When the controller 121 opens the valves 243 a and 243 g, the source gas generated in the vaporization vessel 280 is supplied to the tank 282 via the MFC 241 a.

[0050] The controller 121 controls the control valve of the MFC 241a so that the flow rate of the source gas supplied to the tank 282 is kept constant in the MFC 241a.

[0051] The controller 121 may open the valves 243a and 243g when the pressure value in the tank 282 reaches the target pressure and is maintained at or above the target pressure for a predetermined period of time. On the other hand, the controller 121 is configured to stop the supply of source gas to the tank 282 without opening the valves 243a and 243g when the differential pressure between the pressure on the upstream side (vaporization container 280) of the MFC 241a and the pressure on the downstream side (tank 282) of the MFC 241a deviates from the controllable pressure condition of the MFC 241a, regardless of the target pressure. The target pressure for the pressure value in the tank 282 is preferably set to a pressure range in which the MFC 241a can control the flow rate to a constant value. Furthermore, the target pressure for the pressure value in the tank 282 is preferably determined so as to satisfy the saturated vapor pressure characteristics at the heat resistance temperature of the MFC 241a and the controllable pressure condition of the MFC 241a.

[0052] Next, an example of operation of the gas supply system in this embodiment will be described with reference to Fig. 6. Note that each component of the gas supply system is controlled by a controller 121. Here, the controller 121 is configured to be able to execute the gas supply sequence shown in Fig. 6 in parallel with at least the film formation process steps (S3 to S6) of the substrate processing sequence shown in Fig. 4. Below, a case where the substrate processing sequence and the gas supply sequence are executed in parallel will be described in light of the substrate processing sequence shown in Fig. 4.

[0053] First, the gas supply system is configured so that the source gas is stored in the tank 282 before the start of the film formation process (the above-described film formation process 1) (during step S2 of the substrate processing sequence). Specifically, the source gas is stored in the tank 282 with the valve 243h in a closed state and the valves 243a and 243g in an open state. For example, the source gas is stored in the tank 282 until the pressure value in the tank 282 reaches a threshold value. At this time, the controller 121 executes steps S1 and S2 of the substrate processing sequence, the source filling process, the source vaporization process, and the source charging process in parallel.

[0054] For example, if step S2 of the substrate processing sequence is being executed when the pressure value reaches the threshold value, the controller 121 keeps the valve 243h closed and waits while the pressure value is maintained at the threshold value. Note that the threshold value is not always the same value, but is a value that is arbitrarily set based on film formation processing conditions such as film type or target film thickness. For example, combinations of film type and threshold value may be compiled into a table and stored in advance in the storage device 121c.

[0055] Here, it is preferable that the threshold pressure inside the tank 282 is the same before and after the start of the film forming process. However, it is considered difficult to adjust parameters such as the pressure inside the tank 282 to be the same when the tank 282 is filled with vaporized source gas from an empty state and when the tank 282 is filled with vaporized source gas during the film forming process.

[0056] (Source material supply process in FIG. 6) In synchronization with the start of step S3 (film formation process 1) of the substrate processing sequence, the controller 121 opens the valve 243h to supply the source gas in the tank 282 to the processing chamber 201. In other words, step S3 (film formation process 1) of the substrate processing sequence and the source material supply process of the gas supply sequence are the same process. Then, in order to form a target film thickness, the film formation process of FIG. 4 is repeatedly executed, and the gas supply sequence shown in FIG. 6 is also repeatedly executed. In other words, the four processes shown in FIG. 6 and the four processes (S3 to S6) of the film formation process are executed the same number of times.

[0057] (Raw material filling step in FIG. 6) Next, raw material is supplied from raw material container 270 to vaporization container 280 in an amount sufficient to ensure the flow rate of raw material gas required in film formation step 1. Specifically, when the raw material in vaporization container 280 runs low, raw material is not replenished, but the amount of raw material that was lost in film formation step 1 is supplied. Therefore, the amount of raw material to be replenished is determined to a certain extent, and the set time for this raw material filling step is set (fixed) to a certain time.

[0058] It is also preferable to heat the raw material before supplying it to the vaporization container 280. This can efficiently promote vaporization, thereby shortening the time required to vaporize the raw material. Note that, since the valves 243a and 243g are closed during the raw material supply process, it is considered that there is little impact on the raw material container 270 or the vaporization container 280, and therefore this raw material replenishment process may be performed in parallel with the raw material supply process. This shortens the time required for the gas supply sequence, allowing the time required for the next process (raw material vaporization process) to be extended.

[0059] (Raw material vaporization step in FIG. 6) The controller 121 heats and vaporizes the raw material supplied from the raw material container 270 using a heating unit (not shown). Since it is preferable to completely vaporize the raw material into a gaseous state, it is preferable to set the time for this step longer. For example, it is preferable to set the time longer than the raw material replenishing step and the raw material charging step (described later). The following description will be made with reference to FIG. 8.

[0060] FIG. 8 shows the transition of the pressure in the vaporization container 280 during the four steps shown in FIG. 6 , with the pressure in the vaporization container 280 (pressure detected by the pressure sensor 283) on the vertical axis and time on the horizontal axis. Since the pressure in the vaporization container 280 is constant as shown in FIG. 8 , it is considered that the vaporization of the liquid source supplied to the vaporization container 280 has been completed, or that all of the source supplied to the vaporization container 280 has become gaseous. In FIG. 8 , the wait (WAIT) time is shown as the time during which the pressure in the vaporization container 280 is maintained constant. In other words, the wait (WAIT) time is secured as the time for vaporizing the liquid source in the vaporization container 280. As shown in FIG. 8 , maintaining (converging) the pressure at a constant value (indicated by WAIT) can be an indicator of the completion of vaporization of the liquid source. In this embodiment, by lengthening this wait (WAIT) time as much as possible, the liquid source can be vaporized while maintaining the pressure in the vaporization container 280 constant. However, since vaporization is likely to proceed from the wall side of the vaporization container 280 where the heating unit (not shown) is installed, it is difficult to determine when vaporization has ended. In other words, it is desirable to adjust the wait time to an appropriate time. In Figure 8, the wait time alone takes up approximately 40% of the four steps (one cycle in the figure) shown in Figure 6. Therefore, if the wait time can be adjusted to an appropriate time, i.e., shortened, it is possible to reduce the power required for the heating unit (not shown) (realizing energy savings).

[0061] Similarly, it is known that when a liquid raw material is vaporized, heat of vaporization is generated, and it is thought that maintaining (converging) the temperature at a certain predetermined temperature can also be an indicator.

[0062] (Raw material charging step in FIG. 6) The controller 121 executes the raw material charging step when a preset time (set time) has elapsed in the raw material vaporization step. This set time is set to the time it takes for the pressure inside the tank 282 to converge to a constant value. In addition, the controller 121 keeps the valve 243h closed and opens the valves 243a and 243g to supply the raw material gas, the flow rate of which is controlled by the MFC 241a, from inside the vaporization container 280 into the tank 282.

[0063] The set time for this raw material charging step is fixed because the raw material is vaporized at a predetermined flow rate and the raw material gas, the flow rate of which is controlled by MFC 241a, is supplied into tank 282. Therefore, after the raw material charging step, liquid raw material may remain in vaporization container 280.

[0064] When the pressure value of pressure sensor 281 reaches the threshold value, valves 243a and 243g are closed, and the pressure value of tank 282 is maintained at the threshold value. In this way, controller 121 is configured to complete filling of a predetermined amount of source gas into tank 282 by completing the source filling step, source vaporization step, and source charging step shown in FIG. 6 between the above-mentioned film formation steps 2 to 4 (or during the execution of film formation step 4).

[0065] Furthermore, after the raw material charging step is completed, the vaporization vessel 280 may be filled with the raw material.

[0066] In the raw material filling process, when the raw material is preheated, it is preferable to heat it to a temperature below the vaporization temperature. If the raw material is liquid, the flow rate of the liquid raw material is predetermined. If the raw material is vaporized (phase-changed) before being refilled into the vaporization container 280, it becomes difficult to determine whether the flow rate is the predetermined value. Therefore, it is preferable to heat the raw material to a temperature that does not cause a phase change.

[0067] 6 can be repeated between the above-described film formation steps 2 to 4, the volume of the tank 282 can be increased. As a result, the flow rate of the source material that can be supplied to the processing chamber 201 can be increased as the volume of the tank 282 increases.

[0068] 7A and 7B show changes in the pressure in the process chamber 201 in each cycle when the set time for the raw material vaporization step is changed. The set time for FIG. 7A is short, and the set time for FIG. 7B is long, and the pressure in the process chamber 201 during the raw material supply step is compared.

[0069] 7A and 7B, the pressures in the process chamber 201 at set times for five cycles are compared. The dotted lines in each of FIGS. 7A and 7B indicate the maximum and minimum pressures in the process chamber 201, and the longer the set time for the source material vaporization step, the smaller the pressure difference between cycles.

[0070] In other words, by lengthening the set time of the raw material vaporization process, the pressure inside the vaporization container 280 is maintained constant, which promotes the vaporization of the raw material supplied to the vaporization container 280, allowing the desired flow rate of raw material gas to be stored in the tank 282 and the desired flow rate of raw material gas to be supplied from the tank 282 to the processing chamber 201, thereby reducing the pressure difference when supplying raw material between cycles.

[0071] According to this embodiment, one or more of the following effects (a) to (h) are achieved.

[0072] (a) By lengthening the set time of the raw material vaporization process, the vaporization can be sufficiently carried out within the vaporization container 280, and the vaporization of the raw material within the vaporization container 280 can be advanced, and as a result, the pressure within the vaporization container 280 can be maintained constant.

[0073] (b) By lengthening the set time of the raw material vaporization process, vaporization can be sufficiently carried out within the vaporization container 280, and the vaporization of the raw material supplied into the vaporization container 280 can be completed, so that the pressure within the vaporization container 280 can be maintained constant.

[0074] (c) By setting the raw material vaporization step to a longer time than the raw material filling step and the raw material charging step, sufficient vaporization can be achieved within the vaporization vessel 280. Therefore, the pressure within the vaporization vessel 280 can be maintained constant.

[0075] (d) By lengthening the set time of the raw material vaporization process, the raw material gas sufficiently vaporized in the vaporization vessel 280 can be stored in the tank 282, and therefore the desired flow rate of the raw material gas can be supplied from the tank 282 to the processing chamber 201.

[0076] (e) By lengthening the set time of the source gas vaporization step, it is possible to reduce the variation in the amount of source gas supplied to the processing chamber 201 between cycles.

[0077] (f) By performing the source filling process and the source supply process in parallel, the set time for the source vaporization process can be extended. Therefore, the source gas sufficiently vaporized in the vaporization container 280 can be supplied to the processing chamber 201. Therefore, the variation in the amount of source gas supplied to the processing chamber 201 between cycles can be reduced.

[0078] (g) By performing the film forming process and the gas supply sequence in parallel, in the process of supplying the source gas to the process chamber 201, the source gas can be supplied to the process chamber 201 at a desired flow rate.

[0079] (h) By performing the film forming process and the gas supply sequence in parallel, in the process of supplying the source gas to the process chamber 201, the source gas can be supplied to the process chamber 201 at a desired flow rate.

[0080] (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 of the present disclosure.

[0081] For example, in the above embodiment, the source filling step, the source vaporization step, and the source charging step are performed before the source supply step, but the source filling step, the source vaporization step, and the source charging step may be repeatedly performed. With such a configuration, the capacity of the tank 282 can be increased, and a large flow rate of source gas can be supplied to the process chamber 201.

[0082] For example, in the above-described embodiment, the substrate processing apparatus is configured to use a liquid source as a source material, vaporize the liquid source material, and generate a source gas, and to alternately supply reactants (reactant gases) to form a film on the wafer 200. However, the present disclosure is not limited to such a case.

[0083] The method can also be applied to the case where a source gas is generated by sublimating a solid. As the solid source, a solid source chemical, particularly an inorganic solid source metal, or a semiconductor precursor can be used, for example, HfCl ４ , ZrCl ４ , AlCl ３ , MoO ２ Cl ２ , MoCl ５ or SiI ４ etc. can be used as the solid raw material.

[0084] The liquid source gas may be, for example, monochlorosilane (SiH ３ Cl, abbreviated as MCS) gas, dichlorosilane (SiH ２ Cl ２ , abbreviated as DCS) gas, trichlorosilane (SiHCl ３ , abbreviated as TCS) gas, tetrachlorosilane (SiCl ４ , abbreviation: STC) gas, hexachlorodisilane gas (Si ２ Cl ６ , abbreviation: HCDS) gas, octachlorotrisilane (Si ３ Cl ８ , abbreviated as OCTS) gas can be used. Also, as the source gas, for example, tetrafluorosilane (SiF ４ ) gas, difluorosilane (SiH ２ F ２ fluorosilane-based gases such as tetrabromosilane (SiBr ４ ) gas, dibromosilane (SiH ２ Br ２ ) gas, bromosilane-based gases such as tetraiodosilane (SiI ４ ) gas, diiodosilane (SiH ２ I ２ An iodosilane-based gas such as tetrakis(dimethylamino)silane (Si[N(CH ３ ) ２ ] ４ ) gas, tris(dimethylamino)silane (Si[N(CH ３ ) ２ ] ３H) gas, bis(diethylamino)silane (Si[N(C ２ H ５ ) ２ ] ２ H ２ ) gas, bis(tert-butylamino)silane (SiH ２ [NH(C ４ H ９ )] ２ An aminosilane-based gas such as tetraethoxysilane (Si(OC)) can also be used as the source gas. ２ H ５ ) ４ Alternatively, organic silane source gases such as silane nitrate, ...

[0085] Nitrogen-containing gases include nitrous oxide (N ２ O) gas, nitric oxide (NO) gas, nitrogen dioxide (NO ２ ) gas, ammonia (NH ３ ) gases, etc., can be used.

[0086] The reactant is not limited to a nitrogen-containing gas, and other types of thin films may be formed using gases that react with the source to perform film processing.Furthermore, film formation processing may be performed using three or more types of processing gases.

[0087] In the above embodiment, N is used as the inert gas. ２ Although an example using gas has been described, the present invention is not limited to this, and rare gases such as Ar gas, He gas, Ne gas, and Xe gas may also be used.

[0088] Furthermore, for example, in the above-described embodiments, a film formation process for a semiconductor device has been described as an example of a process performed by a substrate processing apparatus, but the present disclosure is not limited thereto. The technology of the present disclosure can be applied to all processes performed by exposing a workpiece on which a pattern with a high aspect ratio (i.e., a pattern with a depth greater than its width) is formed to a vaporized gas. That is, in addition to film formation processes, processes for forming oxide films, nitride films, and metal-containing films may also be used. Furthermore, although the present embodiments describe a semiconductor manufacturing process, the present disclosure is not limited thereto. For example, the present disclosure can also be applied to substrate processes such as a liquid crystal device manufacturing process, a solar cell manufacturing process, a light-emitting device manufacturing process, a glass substrate processing process, a ceramic substrate processing process, and a conductive substrate processing process.

[0089] It is also possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment, or to add, delete, or replace part of the configuration of each embodiment with another configuration.

[0090] The disclosure of Japanese Patent Application No. 2024-052682, filed on March 28, 2024, is incorporated herein by reference in its entirety.

[0091] All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A gas supply method comprising the steps of: (a) supplying a raw material to a first tank; (b) vaporizing the raw material; (c) supplying a raw material gas obtained by vaporizing the raw material to a second tank; and (d) supplying the raw material gas from the second tank to a processing chamber, wherein (b) is set to a time during which the pressure in the first tank is maintained constant.

2. The gas supply method according to claim 1, wherein steps (a) to (d) are repeatedly performed.

3. The gas supply method according to claim 1, wherein the time is the time it takes for the raw material supplied in (a) to be vaporized.

4. The gas supply method according to claim 1, wherein steps (a) and (d) are carried out in parallel.

5. A gas supply method according to claim 1, wherein the time period (b) is set to be longer than the time periods (a) and (c).

6. The gas supply method according to claim 2, wherein the set time of (a) and the set time of (c) are the same for each cycle in which (a) to (d) are repeatedly executed.

7. The gas supply method according to claim 1, wherein step (d) is executed when the pressure in the second tank reaches a target pressure.

8. The gas supply method according to claim 4, wherein (a) is started before (d) is completed.

9. The gas supply method according to claim 1, further comprising a preheating step of heating the raw material before (a).

10. The gas supply method according to claim 9, wherein in the preheating step, the raw material is heated to a temperature below the vaporization temperature.

11. The gas supply method according to claim 7, wherein the target pressure is set to a pressure that allows the flow rate control unit to control the flow rate to a constant flow rate.

12. A gas supply method according to claim 11, wherein the target pressure is determined by a controllable pressure condition of saturated vapor pressure characteristics at the heat-resistant temperature of the flow rate control section.

13. A method for manufacturing a semiconductor device, comprising the step of supplying a source gas to a processing chamber by the gas supply method according to any one of claims 1 to 12.

14. The method for manufacturing a semiconductor device according to claim 13, wherein the step of supplying the source gas into the processing chamber and (d) are the same step.

15. The method for manufacturing a semiconductor device according to claim 13, wherein the film forming process including the step of supplying the source gas to the processing chamber and the steps (a) to (d) are carried out in parallel.

16. A method for manufacturing a semiconductor device according to claim 15, wherein the time period of (b) is set so that the time period from the start of (a) to the end of (c) is equal to or less than the time period of the film forming process excluding the time period for the process of supplying the source gas to the process chamber.

17. A method for manufacturing a semiconductor device according to claim 13, wherein in (c), when the pressure in the second tank reaches a target pressure, the target pressure is maintained until the step of supplying the source gas to the processing chamber is started.

18. A program that causes a controller to execute the following steps: (a) a procedure for supplying a raw material to a first tank; (b) a procedure for vaporizing the raw material; (c) a procedure for supplying a raw material gas obtained by vaporizing the raw material to a second tank; and (d) a procedure for supplying the raw material gas from the second tank to a processing chamber, wherein in step (b), the program causes the controller to set a time during which the pressure in the first tank is maintained constant.

19. A gas supply system comprising: a first tank for vaporizing a raw material; a second tank for storing a raw material gas obtained by vaporizing the raw material; a controller for executing the following (a) to (d): (a) a process for supplying the raw material to the first tank; (b) a process for vaporizing the raw material; (c) a process for supplying the raw material gas obtained by vaporizing the raw material to the second tank; and (d) a process for supplying the raw material gas from the second tank to a processing chamber, wherein (b) is configured to be set to a time during which the pressure in the first tank is maintained constant.

20. A processing apparatus comprising the gas supply system of claim 19.

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