JP2023129319A - Raw material supply system, substrate processing apparatus and method for manufacturing semiconductor device - Google Patents

Abstract

To provide a technology that allows multiple raw materials to be supplied by a single raw material supply system.SOLUTION: A configuration capable of supplying a plurality of raw materials to a processing chamber, comprises a first gas supply line configured to be capable of supplying a first precursor gas produced by the first raw material to the processing chamber by controlling the flow rate of the first precursor gas with a flow rate controller, and a second gas supply line configured to be capable of supplying a second precursor gas produced by the second raw material to the processing chamber, and a configuration is provided in which the flow rate of the second precursor gas is determined based on the differential pressure between the primary pressure of the flow controller in the first gas supply line and the supply pressure of the second precursor gas from the second gas supply line to the processing chamber.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to a raw material supply system, a substrate processing apparatus, and a method for manufacturing a semiconductor device.

2. Description of the Related Art Conventionally, a semiconductor manufacturing apparatus for manufacturing semiconductor devices is known as an example of a substrate processing apparatus. For example, substrate processing is performed in which a processing gas is supplied into a reaction tube and a substrate (hereinafter also referred to as a "wafer") is processed under predetermined processing conditions. In recent years, various processing gases have been used, such as a gas obtained by vaporizing a liquid or a gas obtained by sublimating a solid (see, for example, Patent Document 1).

Typically, processing gases generated from raw materials with different characteristics are generated and supplied by different systems. Furthermore, within the same supply system, a plurality of processing gases are supplied by switching valves in consideration of the pressure on the secondary side of the supply valve. However, it may be difficult to supply a stable constant flow rate due to the influence (interference) of fluctuations in the pressure on the downstream side of the valve.

JP2018-090834A

An object of the present disclosure is to provide a technology that allows a single raw material supply system to supply a plurality of raw materials.

According to one aspect of the present disclosure, the configuration is such that a plurality of raw materials can be supplied to the processing chamber,
A first gas supply line configured to control the flow rate of a first precursor gas generated by a first raw material using a flow rate controller and supply the first precursor gas to the processing chamber;
a second gas supply line configured to be able to supply a second precursor gas generated by a second raw material having a lower vapor pressure than the first raw material to the processing chamber;
The flow rate of the second precursor gas is determined based on the pressure difference between the primary side pressure of the flow rate controller provided in the first gas supply line and the secondary side pressure of the second gas supply line. provided.

According to the present disclosure, one raw material supply system can stably supply a plurality of raw materials.

1 is a vertical cross-sectional view showing a schematic configuration of a processing furnace of a substrate processing apparatus according to an embodiment of the present disclosure. 2 is a schematic cross-sectional view taken along line AA in FIG. 1. FIG. 1 is a schematic diagram of a peripheral structure of a processing furnace of a substrate processing apparatus according to an embodiment of the present disclosure. 1 is a schematic diagram showing a raw material supply system of a substrate processing apparatus according to an embodiment of the present disclosure. 1 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. FIG. 3 is a diagram showing the relationship between the primary side pressure of the flow rate controller and the carrier gas flow rate according to an embodiment of the present disclosure. FIG. 3 is a diagram showing characteristics of a flow rate controller according to an embodiment of the present disclosure. 3 is a flowchart of a substrate processing process according to an embodiment of the present disclosure. 1 is an example of a flowchart of a substrate processing process according to an embodiment of the present disclosure. 1 is an example of a flowchart of a substrate processing process according to an embodiment of the present disclosure. FIG. 7 is a diagram showing a modification of the second fixed raw material supply system according to an embodiment of the present disclosure. FIG. 7 is a diagram showing an example of gas flow rate control of the second fixed raw material supply system according to an embodiment of the present disclosure. FIG. 7 is a diagram showing an example of gas flow rate control of the second fixed raw material supply system according to an embodiment of the present disclosure.

As shown in FIG. 1, the processing furnace 202 includes a heater 207 as a heating means (heating mechanism). The heater 207 has a cylindrical shape and is vertically installed by being supported by a heater base (not shown) serving as a holding plate.

Inside the heater 207, a reaction tube 203 constituting a reaction container (processing container) is arranged concentrically with the heater 207. The reaction tube 203 is made of a heat-resistant material (for example, quartz (SiO ₂ ) or silicon carbide (SiC)), and is formed into a cylindrical shape with a closed upper end and an open lower end. The processing chamber 201 is configured to be capable of accommodating wafers 200 as substrates in a boat 217 (to be described later) in a horizontal position and arranged in multiple stages in the vertical direction.

In the processing chamber 201, nozzles 410, 420, and 430 are provided so as to penetrate the side wall of the manifold 209. Gas supply pipes 310, 320, 330 as gas supply lines are connected to the nozzles 410, 420, 430, respectively. In this way, the reaction tube 203 is provided with three nozzles 410, 420, 430 and three gas supply pipes 310, 320, 330, and multiple types of gas (processing gas) are supplied to the processing chamber 201. It is configured to be able to supply

However, the processing furnace 202 of this embodiment is not limited to the above-mentioned form. For example, a metal manifold supporting the reaction tube 203 may be provided below the reaction tube 203, and each nozzle may be provided so as to penetrate the side wall of the manifold. In this case, the manifold may further be provided with an exhaust pipe 231, which will be described later. Even in this case, the exhaust pipe 231 may be provided at the lower part of the reaction tube 203 instead of the manifold. In this way, the furnace mouth of the processing furnace 202 may be made of metal, and a nozzle or the like may be attached to this metal furnace mouth.

From the gas supply pipe 310, an O-containing gas as a reaction gas (reactant) containing oxygen (O) is supplied as a processing gas to the processing chamber 201 via a nozzle 410. As the O-containing gas, an N-containing gas that does not contain metal elements can be used.

From the gas supply pipe 320, an N-containing gas as a reaction gas (reactant) containing nitrogen (N) is supplied as a processing gas to the processing chamber 201 via a nozzle 420. As the N-containing gas, an N-containing gas that does not contain metal elements can be used.

From the gas supply pipe 330, a raw material gas (hereinafter also simply referred to as a precursor gas) obtained by sublimating a solid raw material (solid raw material) to a gaseous state at room temperature and normal pressure is supplied to the processing chamber 201 as a processing gas. Ru. As will be described later, a solid raw material containing a plurality of metal elements is supplied from the gas supply pipe 330 to the processing chamber 201 . For example, a metal raw material containing a metal element but not containing carbon (C), that is, an inorganic metal raw material (inorganic metal compound), and a halogen raw material (also referred to as a halide raw material) is used. In addition, as will be described later, from the gas supply pipe 330, a raw material gas (a raw material gas ( (second precursor gas) can be supplied to the processing chamber 201, respectively. In this embodiment, the gas supply pipe 330 is connected to a raw material supply system 100, which will be described later, and which is configured to be able to supply raw materials containing a plurality of metal elements.

Here, as long as the material contains the same element (eg, halogen element) as the predetermined element (eg, metal) that forms the core of the solid raw material, it can be used as one raw material supply line. For example, if the predetermined element is a material other than a metal (other than a solid raw material) but contains the same element (for example, a halogen element), it can be added to one raw material supply line. However, the conditions that can be configured in the same raw material supply line are (1) the piping temperature of the common part is below the thermal decomposition temperature of both materials, and (2) each raw material does not react with each other. If these conditions are satisfied, a raw material supply line for supplying a raw material containing an element other than the solid raw material, such as silicon (Si) element, can be included in FIG. 4, which will be described later.

As shown in FIG. 2, nozzles 410, 420, 430 are connected to the tips of the gas supply pipes 310, 320, 330. The horizontal portions of the nozzles 410, 420, and 430 are provided so as to penetrate the side wall of the manifold 209. The vertical portions of the nozzles 410, 420, and 430 extend upward along the inner wall of the reaction tube 203 (upward in the loading direction of the wafers 200) into an annular space formed between the inner wall of the reaction tube 203 and the wafers 200. The wafer array area is provided so as to rise toward the wafer array area (that is, to rise from one end of the wafer array area to the other end). That is, the nozzles 410, 420, and 430 are provided along the wafer arrangement region in a region horizontally surrounding the wafer arrangement region on the side of the wafer arrangement region where the wafers 200 are arranged.

Gas supply holes 410a, 420a, 430a for supplying (spouting) gas are provided on the side surfaces of the nozzles 410, 420, 430. Gas supply holes 410a, 420a, and 430a are open toward the center of reaction tube 203. A plurality of these gas supply holes 410a, 420a, and 430a are provided from the bottom to the top of the reaction tube 203, each having the same opening area, and further provided at the same opening pitch. However, the gas supply holes 410a, 420a, 430a are not limited to the above-mentioned form. For example, the opening area of the reaction tube 203 may be gradually increased from the bottom to the top. This makes it possible to equalize the flow rate of gas supplied from the gas supply holes 410a, 420a, and 430a.

As described above, in this embodiment, the nozzles 410 and 420 are arranged in the annular vertical space formed by the inner wall of the reaction tube 203 and the ends of the plurality of wafers 200, that is, in the cylindrical space. , 430. Then, gas is ejected into the reaction tube 203 for the first time in the vicinity of the wafer 200 from gas supply holes 410a, 420a, and 430a opened in the nozzles 410, 420, and 430, respectively. The main flow of gas within the reaction tube 203 is parallel to the surface of the wafer 200, that is, in the horizontal direction. With such a configuration, gas can be uniformly supplied to each wafer 200, and the uniformity of the thickness of the thin film formed on each wafer 200 can be improved. The residual gas after the reaction that has flowed on the surface of the wafer 200 flows toward an exhaust port, that is, an exhaust pipe 231 that will be described later. However, the direction of flow of this residual gas is appropriately specified depending on the position of the exhaust port, and is not limited to the vertical direction.

The reaction tube 203 is provided with an exhaust pipe 231 that exhausts the atmosphere of the processing chamber 201 . The exhaust pipe 231 is connected to a pressure sensor 245 as a pressure detector (pressure detection unit) that detects the pressure in the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 as a pressure regulator (pressure adjustment unit). A vacuum pump 246 as a vacuum evacuation device is connected. The APC valve 244 can perform evacuation and stop evacuation of the processing chamber 201 by opening and closing the valve while operating the vacuum pump 246 as an evacuation device. The valve is configured such that the pressure in the processing chamber 201 can be adjusted by adjusting the valve opening degree based on pressure information detected by the pressure sensor 245 in this state. An exhaust system is mainly composed of an exhaust pipe 231, an APC valve 244, and a pressure sensor 245. The vacuum pump 246 may be included in the exhaust system.

A seal cap 219 is provided below the reaction tube 203 as a furnace mouth cover that can airtightly close the lower end opening of the reaction tube 203 . The seal cap 219 is configured to abut the lower end of the reaction tube 203 from below in the vertical direction. The seal cap 219 is made of metal such as SUS, and has a disk shape. An O-ring 220 serving as a sealing member that comes into contact with the lower end of the reaction tube 203 is provided on the upper surface of the seal cap 219 .

A rotation mechanism 267 for rotating a boat 217, which will be described later, is installed on the side of the seal cap 219 opposite to the processing chamber 201. The rotation shaft 255 of the rotation mechanism 267 passes through the seal cap 219 and is connected to the boat 217. The rotation mechanism 267 is configured to rotate the wafer 200 by rotating the boat 217. The seal cap 219 is configured to be vertically raised and lowered by a boat elevator 115 serving as a lifting mechanism installed vertically outside the reaction tube 203. The boat elevator 115 is configured to be able to carry the boat 217 into and out of the processing chamber 201 by raising and lowering the seal cap 219.

The boat 217 serving as a substrate support is configured to support a plurality of wafers 200, for example, 25 to 200 wafers 200 in a horizontal position and aligned vertically with their centers aligned with each other in multiple stages. They are arranged so that they are spaced apart. The boat 217 is made of a heat-resistant material such as quartz or SiC. At the bottom of the boat 217, heat insulating plates 218 made of a heat-resistant material such as quartz or SiC are supported in multiple stages in a horizontal position. This configuration makes it difficult for the heat from the heater 207 to be transmitted to the seal cap 219 side. However, this embodiment is not limited to the above-mentioned form. For example, instead of providing the heat insulating plate 218 at the bottom of the boat 217, a heat insulating tube configured as a cylindrical member made of a heat-resistant material such as quartz or SiC may be provided.

A temperature sensor 263 as a temperature detector is installed inside the reaction tube 203, and the temperature inside the processing chamber 201 is adjusted by adjusting the amount of electricity supplied to the heater 207 based on the temperature information detected by the temperature sensor 263. It is configured to provide a desired temperature distribution. The temperature sensor 263 is configured in an L-shape like the nozzles 410, 420, and 430, and is provided along the inner wall of the reaction tube 203.

Next, the peripheral structure of the processing furnace 202 of the substrate processing apparatus 10 will be described. The processing chamber 201 is provided with a first gas supply pipe 310, a second gas supply pipe 320, and a third gas supply pipe 330.

The first gas supply pipe 310 is divided into first branch pipes 82a and 82b at the upstream side. Upstream, it is divided into first branch pipes 82a and 82b. An oxidizing gas supply source 86 that supplies, for example, oxygen gas as the first raw material is connected to the first branch pipe 82a via a valve v3 and an MFC (Mass Flow Controller) 84a as a flow rate controller. There is. A first inert gas supply source 88 that supplies an inert gas such as nitrogen (N ₂ ) as a first inert gas is connected to the first branch pipe 82b via a valve v4 and an MFC 84b. There is. Hereinafter, when simply referring to a pipe branching from the first gas supply pipe 310, it will be collectively referred to as the first branch pipe 82, and when referring to an MFC provided in the second branch pipe 82, it will be collectively referred to as the first branch pipe 82. It is sometimes referred to as MFC84. Hereinafter, in this specification, numbers may be added according to the same rule.

In this way, the first gas supply pipe 310 introduces the first raw material gas as the first reaction gas or the mixed gas of the first raw material gas and an inert gas such as _N2 into the processing chamber 201. be able to. Mainly, the first gas supply pipe 310, the first branch pipe 82a, the valve v2, the MFC 84a, and the first raw material gas supply source 86 constitute, for example, a first raw material gas supply system.

The second gas supply pipe 320 is divided into second branch pipes 72a and 72b at the upstream side. A nitriding gas supply source 76 that supplies nitriding gas as a second raw material gas is connected to the second branch pipe 72a via a valve v1 and an MFC 74a. A second inert gas supply source 78 that supplies an inert gas such as N ₂ as a second inert gas is connected to the second branch pipe 72b via a valve v2 and an MFC 74b. Hereinafter, when simply indicating a pipe branching from the first gas supply pipe 310, it will be referred to as a second branch pipe 72, and when referring to an MFC provided in the second branch pipe 72, it will be referred to as an MFC 74. Sometimes.

In this way, the second gas supply pipe 320 introduces the second raw material gas as the second reaction gas, or the second raw material gas and an inert gas such as N ₂ into the processing chamber 201 . A nitriding gas supply system is mainly composed of the second gas supply pipe 320, the second branch pipe 72a, the valve v1, the MFC 74a, and the nitriding gas supply source 76.

Inert gases supplied from the first inert gas supply source 88 and the second inert gas supply source 78 may be used. These gases may act as a purge gas, diluent gas, or carrier gas in a substrate processing step to be described later. Note that each of the first gas supply pipe 310, the second gas supply pipe 320, and the third gas supply pipe 330 may be provided with a vent pipe for discharging the gas to the outside.

A control unit 121 (not shown) is electrically connected to components such as the valves v1 to v4, the MFC 74, the MFC 84, the APC valve 243, and the exhaust device 246. The control unit 121 controls these components at desired timing so that the flow rate of gas to be supplied, the pressure of the processing chamber 201, etc. become predetermined values. Here, MFC74 and MFC84 are generic terms for MFC74a, 74b and MFC84a, 84b, respectively.

The raw material supply system 100 shown in FIG. 4 is connected to the third gas supply pipe 330. Hereinafter, the raw material supply system 100 connected to the third gas supply pipe 330 according to the present embodiment will be specifically described with reference to FIG. 4.

In the raw material supply system 100, a first solid raw material 50a is arranged in a first raw material container 60a, and a gas (hereinafter referred to as a first precursor) is obtained by sublimating the first solid raw material 50a by heating the first raw material container 60a. A first precursor gas supply system 100a that supplies a gas (sometimes referred to as gas) to the processing chamber 201 via a third gas supply pipe 330, and a second solid raw material 50b are arranged in a second raw material container 60b. Gas obtained by sublimating the second solid raw material 50b by heating the second raw material container 60b (hereinafter also referred to as second precursor gas) is supplied to the processing chamber 201 via the third gas supply pipe 330. The second precursor gas supply system 100b is configured to have a second precursor gas supply system 100b.

As shown in FIG. 4, the first precursor gas supply system 100a and the second precursor gas supply system 100b are connected to a processing chamber 201 from an on-off valve 97 (hereinafter also referred to as a final valve FV) as an on-off section. The configuration includes a common gas supply pipe 330 and nozzle 430. In other words, the on-off valve 97 is a component provided on the gas supply pipe 330 and closest to the processing chamber 201. Note that the line from the first raw material container 60a to the on-off valve 97 is called a first solid raw material supply line (first precursor gas supply line), and the line from the second raw material container 60b to on-off valve 97 is called a second solid raw material supply line (first precursor gas supply line). 2 precursor gas supply line).

Further, in this embodiment, since the first solid raw material 50a and the second solid raw material 50b have different vapor pressure characteristics, different configurations and raw material supply methods are adopted. For example, different supply control methods are used, such as a self-sublimation method for the first solid raw material 50a, which has a relatively high vapor pressure, and a carrier gas flow method for the second solid raw material 50b, which has an extremely low vapor pressure. The self-sublimation method is also called a vapor draw method, and is a method in which the first raw material container 60a is changed from a solid state to a phase only by heating by a tank heater (hereinafter referred to as the first sub-heater) 70a as a sub-heater to generate a first precursor gas. It is. Although not shown, this first precursor gas can be appropriately mixed with a carrier gas at the outlet of the first raw material container 60a. In this method, carrier gas is not supplied into the first raw material container 60a. In the carrier gas flow method, while the second raw material container 60b is heated by a second tank heater (hereinafter referred to as second sub-heater) 70b as a sub-heater, a carrier gas whose flow rate is adjusted by the MFC 96 is passed through the second introduction pipe 350b. This method generates a second precursor gas by supplying it to the second raw material container 60b, causing a phase change from a solid. Although not shown in FIG. 4, it is preferable that this carrier gas be heated in advance to a temperature higher than the temperature at which the second solid raw material 50b undergoes a phase change.

In this embodiment, the first raw material supply line is configured to be able to supply to the processing chamber 201 a gas obtained by subliming the first solid raw material 50a whose flow rate is adjusted by the MFC 99, and a sublimated second solid raw material 50b. a second raw material supply line configured to be able to supply gas to the processing chamber 201, and the flow rate of the gas that sublimates the second solid raw material 50b supplied to the second raw material supply line is equal to the first raw material supply. It is determined by the differential pressure between the primary side pressure and the secondary side pressure of the MFC99 provided in the line. Although details will be described later, in this case, gases obtained by sublimating the first solid raw material 50a and the second solid raw material 50b (first precursor gas and second precursor gas) can be simultaneously supplied to the processing chamber 201. . That is, the gases obtained by sublimating the first solid raw material 50 a and the second solid raw material 50 b can be mixed in the gas supply pipe 330 and then supplied to the processing chamber 201 through the nozzle 430 .

(On-off valve 97)
These are valves for supplying the first precursor gas and the second precursor gas (gases obtained by sublimating the first solid raw material 50a and the second solid raw material 50b, respectively) to the processing chamber 201, and are connected to the first raw material supply line and the second precursor gas. The two raw material supply lines are connected just before the on-off valve 97. Specifically, the above-mentioned "immediately before" means that a location (piping) where the first raw material supply line and the second raw material supply line are branched is provided close to the on-off valve 97. Further, it is preferable that the on-off valve 97 be provided as close to the processing chamber 201 as possible. Thereby, the influence of mutual interference between the first raw material supply line and the second raw material supply line can be suppressed.

(Configuration of the first solid raw material supply line)
The first precursor gas supply system 100a includes a first solid raw material supply line, an on-off valve 97, and piping from the on-off valve 97 to the processing chamber 201. The raw material supply line will be explained.

In the first solid raw material supply line, a first supply valve 110a, a pressure gauge 109a as a pressure sensor, an MFC 99, a valve v7a, and a first raw material container 60a are installed in a first raw material supply pipe 330a in the upstream direction from the on-off valve 97. The first sub-heater 70a is provided so as to surround the first raw material container 60a, and is configured to be able to heat the first raw material container 60a. By heating the first sub-heater 70a, the first solid raw material 50a in the first raw material container 60a is heated to a temperature higher than that at which it changes to a gaseous state.

Further, the first solid raw material supply line has a first pipe heater 71a as a pipe heating section that heats the first raw material supply pipe 330a, the MFC 99, the pressure gauge 109, and the opening/closing part 97, respectively, and the first solid raw material supply line The temperature is controlled to be above the vaporization temperature. Note that the first pipe heater 71a is preferably controlled to a higher temperature than the first raw material container 60a in order to suppress the phase shift of the first precursor gas from the gaseous state.

Further, a first introduction pipe 350a is connected upstream of the first raw material container 60a, and the first introduction pipe 350a is provided with an introduction valve v5a and a primary valve v6a. Furthermore, an MFC 96 is provided upstream of the introduction pipe 350a and connected to the inert gas source 101. Note that the MFC 96 and the inert gas source 101 are shared with a second introduction pipe 350b, which will be described later. In addition, since the bypass line is provided with a valve v8a and the inert gas can be supplied into the first raw material supply pipe 330a without passing through the first raw material container 60a, the inside of the first raw material supply pipe 330a can be purged. can do. These first introduction pipe 350a, bypass line, introduction valve v5a, primary valve v6a, and bypass valve v8a are also included in the first precursor gas supply system 100a.

(MFC)
The MFC 99 of this embodiment is, for example, a differential pressure type MFC. The MFC 99 also sets the supply pressure of the first precursor gas from the first solid raw material container 60a as the first raw material source on the upstream side of the orifice to P1, and the pressure P2 on the downstream side of the orifice (the pressure detected by the pressure sensor 109). ), as long as the differential pressure (pressure P2 - pressure P1) is within a controllable range, it is possible to keep the flow rate of the first precursor gas constant against pressure fluctuations in the first solid raw material container 60a. be. For example, the pressure P2 is maintained at a pressure value that satisfies the choke flow conditional expression in the orifice of "P1≧2P2". Note that the MFC 99 of this embodiment is not particularly limited to the above-mentioned differential pressure type MFC, and it goes without saying that it may be a thermal type MFC, for example.

FIG. 7 shows a conceptual diagram of the characteristics of MFC99. As shown in FIG. 7, area A is an area that cannot be controlled due to insufficient differential pressure (pressure P2 - pressure P1), area B is a controllable area, and area C is controllable but particles This is a region where there is a risk of generation (a region where transition from gas to solid is likely).

In this embodiment, by controlling the pressure on the primary side and the secondary side of the MFC 99, it is possible to adjust to the conditions in the region B of the MFC 99 so as not to exceed the control limit value of the MFC 99. The first precursor gas can be supplied to the processing chamber 201 without causing a phase change (solidification in the case of a solid raw material) of the gas. Thereby, the first precursor gas can be spread over the surface of the wafer 200, and the in-plane film thickness uniformity of a single wafer 200 and the film thickness uniformity between each wafer 200 can be improved. Further, a plurality of MFCs 99 may be provided in parallel. Thereby, the flow rate of the first precursor gas that can be supplied from the MFC 99 can be increased.

In this embodiment, as shown in FIG. 4, while the first precursor gas is being supplied to the processing chamber 201, the introduction valve v5a, the primary valve v6a, and the bypass valve v8a remain closed. Further, the inert gas source 101 is connected to the first raw material container 60a via these valves (v5a, v6a). This embodiment is applicable not only to the case where the first solid raw material 50a and the first solid raw material 50b have different vapor pressures, but also to the case where the first solid raw material 50a has the same vapor pressure as the first solid raw material 50b. It's for a reason. In other words, the method for supplying the first precursor gas and the second precursor gas may be the same. Further, although FIG. 4 shows two lines for supplying solid raw materials, there is no reason for there to be two lines, and there may be three or more lines.

(Operation of the first solid raw material supply line)
FIG. 4 shows how the first precursor gas is supplied to the processing chamber 201. At this time, the introduction valve v5a, the primary valve v6a, and the bypass valve v8a are in a closed state, and the secondary valve v7a, the first supply valve 110a, and the on-off valve 97 are in an open state. The controller 121 heats the first solid raw material 50a in the first raw material container 60a with the first sub-heater 70a, and processes the gas (first precursor gas) obtained by sublimating the first solid raw material 50a while controlling the flow rate with the MFC 99. It is configured to supply the chamber 201. The supply of the first precursor gas is stopped by closing the secondary valve v7a or the first supply valve 110a.

(Configuration of second solid raw material supply line)
Next, the second solid raw material supply line will be explained using FIG. 4. The second precursor gas supply system 100b has a configuration that includes at least a second solid raw material supply line, an on-off valve 97, and piping from the on-off valve 97 to the processing chamber 201, and the second solid raw material supply line has an on-off and on-off valve. Upstream from the valve 97, a second supply valve 110b, a pressure gauge 109b as a pressure sensor, a mass flow meter (Mass Flow Mator) MFM98 as a flow rate monitor, a valve v7b, and a second raw material container 60b supply the second raw material. It is provided in the tube 330b.

The second sub-heater 70b is provided so as to surround the second raw material container 60b, and is configured to be able to heat the second raw material container 60b. By heating the second sub-heater 70b, the second solid raw material 50b in the second raw material container 60b is heated to a temperature higher than that at which it changes to a gaseous state. Further, the second solid raw material supply line has a second pipe heater 71b as a pipe heating section that heats the second raw material supply pipe 330b, the MFM 98, the pressure sensor 109b, and the opening/closing part 97, respectively, and the second solid raw material supply line The temperature is controlled to be above the vaporization temperature. Note that the second pipe heater 71b is preferably controlled to a higher temperature than the second raw material container 60b in order to suppress the phase shift of the second precursor gas from the gaseous state.

Further, a second introduction pipe 350b is connected upstream of the second raw material container 60b, and the second introduction pipe 350b is provided with an introduction valve v5b and a primary valve v6b, and further upstream of the second introduction pipe 350b. is equipped with an MFC 96 and connected to an inert gas source 101. In addition, since the bypass line is provided with a valve v8b and the inert gas can be supplied into the second raw material supply pipe 330b without passing through the second raw material container 60b, the inside of the second raw material supply pipe 330b can be purged. can do. These first introduction pipe 350a, bypass line, introduction valve v5a, primary valve v6a, and bypass valve v8a are also included in the second precursor gas supply system 100b.

A second introduction pipe 350b serving as a pressurized gas supply pipe is connected to the second solid raw material container 60b, and the pressurized gas supply pipe 350b is supplied with pressure via the above-mentioned introduction valve v5b, primary valve v6b, and MFC96. An inert gas source 101 as a gas supply source is connected. By supplying the pressurized gas from the pressurized gas supply pipe 350b, the gas (second precursor gas) sublimated in the second solid raw material container 60b is introduced into the processing chamber 201 from the third gas supply pipe 330. . As the carrier gas (hereinafter also referred to as pressurized gas), it is preferable to use an inert gas that does not react with the raw material. Since the pressurized gas promotes sublimation of the second solid raw material 50b, the flow rate of the second precursor gas can be increased by increasing the flow rate of the pressurized gas.

In this way, the second solid material supply line introduces the second precursor gas (actually, a mixed gas of the second precursor gas and the pumped gas) into the processing chamber 201. The second solid raw material supply line is mainly connected to the third gas supply pipe 330b, MFM98, second solid raw material container 60b, pressurized gas supply pipe 350b, introduction valve v5b, primary valve v6b, MFC96, and inert gas source 101. configured.

(Operation of the second solid raw material supply line)
FIG. 4 shows how the second precursor gas is supplied to the processing chamber 201. At this time, the bypass valve v8b is in the closed state, and the introduction valve v5b, the primary valve v6b, the secondary valve v7b, the second supply valve 110b, and the on-off valve 97 are in the open state. The controller 121 heats the second solid raw material 50b in the second raw material container 60b with the second sub-heater 70b, and generates a mixed gas of the sublimated second solid raw material 50b (second precursor gas) and the pressurized gas. The flow rate is monitored by the MFM 98 while being supplied to the processing chamber 201 . Further, the supply of the second precursor gas is stopped by closing the secondary valve v7b or the second supply valve 110b. Further, at this time, the supply of pressurized gas may also be stopped.

(Flow rate monitoring of the second solid raw material supply line)
First, although there is an MFM 98 as a flow rate monitor on the secondary side (downstream side) of the second raw material container 60b, the flow rate cannot be controlled by the MFM 98 alone. Therefore, regarding the second solid raw material 50b, when the pressure on the secondary side (downstream side) changes, the amount of sublimation changes (as the pressure on the secondary side increases, the amount of sublimation decreases), so the flow rate is monitored using the MFM 98. , it is possible to appropriately control the flow rate by changing the carrier gas (pressured gas).

The MFM 98 monitors the mixed gas of the second precursor gas and the carrier gas, and cannot directly monitor the flow rate of the second precursor gas. In this embodiment, the MFC 96 is provided on the primary side, and when the flow rate supplied by the MFC 96 is the flow rate A, and the flow rate monitored by the MFM 98 is the flow rate B, the following equation is given.
Flow rate of second precursor gas = (Flow rate B−Flow rate A)) × Cf
Here, Cf is the conversion factor of the second precursor gas. However, the conversion factor is a value based on the conversion factor of the MFC96 calibration gas as 1.0. Thereby, in this embodiment, the flow rate of the second precursor gas can be measured.

FIG. 6 shows the relationship between the pressures of the first solid raw material supply line and the second solid raw material supply line. The vertical axis represents the pressure, and the horizontal axis represents the gas flow rate, specifically, the flow rate of the gas introduced into the second solid material supply line in order to supply the second precursor gas to the processing chamber 201. Note that this flow rate includes the flow rate of a diluent gas, which will be described later, that is supplied in addition to the carrier gas. In addition, if the first solid raw material is only to be sublimated, the temperature may be raised by the first subheater 70a, but the higher the temperature, the higher the risk of solidification and corrosion, so the temperature should not be raised excessively, and the temperature should be almost sublimated. The first sub-heater 70a is controlled so that the temperature is near (near the saturated vapor pressure). Therefore, the primary side pressure of the MFC 99 shown in FIG. 6 is approximately the saturated vapor pressure of the first solid raw material 50a.

As shown in FIG. 6, the difference between the pressure on the secondary side of the second solid raw material supply line and the pressure on the primary side of the first solid raw material supply line is controlled so as not to reach the control limit value of the MFC 99. Although it is possible to increase the flow rate of the second precursor gas by increasing the flow rate of the gas as described above, if this increases the pressure on the secondary side of the first solid raw material supply line too much, The control limit value of the MFC99 is reached, and it becomes impossible to supply the first precursor gas. Therefore, the controller 121 is configured to monitor the differential pressure.

Specifically, the controller 121 obtains the supply pressure of the first precursor gas by heating and sublimating the first solid raw material in the first solid raw material supply line, and supplies the first precursor gas to the second gas supply line. The flow rate of the second precursor gas to be calculated is calculated, the secondary side pressure of the second solid material in the second gas supply line at that time is obtained, and the primary side pressure ( The control limit value of the MFC99 is the pressure difference between the pressure on the primary side of the MFC99) and the supply pressure of the mixed gas of the second precursor gas and carrier gas flowing into the second gas supply line (the pressure on the secondary side of the second gas supply line). Check whether it exceeds.

The confirmation by the controller 121 is performed before supplying the first precursor gas or the second precursor gas to the processing chamber 201. Thereby, a desired amount of the first precursor gas or the second precursor gas can be continuously supplied to the processing chamber 201 at the same time.

As shown in FIG. 5, the controller 121, which is a control unit (control means), is configured as a computer equipped with a CPU (Central Processing Unit) 121a, a RAM (Random Access Memory) 121b, a storage device 121c, and an I/O port 121d. has been done. The RAM 121b, storage device 121c, and I/O port 121d are configured to be able to exchange data with the CPU 121a via an internal bus. An input/output device 122 configured as, for example, a touch panel is connected to the controller 121 .

The storage device 121c is configured with, for example, a flash memory, an HDD (Hard Disk Drive), or the like. In the storage device 121c, a control program for controlling the operation of the substrate processing apparatus, a process recipe in which procedures, conditions, etc. of substrate processing to be described later are described, and the like are stored in a readable manner. The process recipe is a combination of instructions that causes the controller 121 to execute each procedure in the substrate processing step described later to obtain a predetermined result, and functions as a program. Hereinafter, this process recipe, control program, etc. will be collectively referred to as simply a program. When the word program is used in this specification, it may include only a single process recipe, only a single control program, or both. The RAM 121b is configured as a memory area (work area) in which programs, data, etc. read by the CPU 121a are temporarily held. In this embodiment, the storage device 121c stores at least the relationship between the control limit range of the flow rate controller shown in FIG. 6 and the differential pressure between the primary side pressure (saturated vapor pressure) and the secondary side pressure of the solid raw material. , and characteristic data including the control limit range of the flow rate controller shown in FIG. 7 are stored.

The I/O port 121d includes the above-mentioned MFCs 96, 99, MFM 98, valves v1 to v8, 110, APC valve 243, pressure sensors 109, 245, vacuum pump 246, heater 207, first sub-heater 70 and piping heater 71, and rotation mechanism. 267, the boat elevator 115, etc.

The CPU 121a is configured to read and execute a control program from the storage device 121c, and read a process recipe from the storage device 121c in response to input of an operation command from the input/output device 122. In accordance with the read process recipe, the CPU 121a adjusts the flow rate of various gases by each MFC, opens and closes each valve, opens and closes the APC valve 243, and adjusts the pressure by the APC valve 243 based on the pressure sensor 245 and the temperature sensor 263. It is configured to control the temperature adjustment operation of the heater 207, the starting and stopping of the vacuum pump 246, the rotation and rotational 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, and the like. In addition, in this embodiment, the on-off valve 97, the MFC96, MFC99, and MFM98 that respectively constitute the first solid raw material supply line and the second solid raw material supply line, the pressure gauge 109, the valves v5 to v8, the supply valve 110, the subheater 70, It controls the operation of the pipe heater 71, etc.

The controller 121 is not limited to being configured as a dedicated computer, but may be configured as a general-purpose computer. For example, an external storage device storing the above program (e.g., magnetic tape, magnetic disk such as a flexible disk or hard disk, optical disk such as CD or DVD, magneto-optical disk such as MO, semiconductor memory such as USB memory or memory card) The controller 121 of this embodiment can be configured by preparing the external storage device 123 and installing a program on 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 the program via the external storage device 123. For example, the program may be supplied without going through the external storage device 123 using 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 will be collectively referred to as simply recording media. When the term "recording medium" is used in this specification, it may include only the storage device 121c, only the external storage device 123, or both.

<Substrate processing method>
Next, an example of processing the wafer 200 will be described. As an example of a semiconductor device manufacturing process, an example in which a film is formed on a wafer 200 will be described. First, as described above, the wafers 200 are loaded onto the boat 217 and carried into the processing chamber 201 (step S1 in FIG. 8). At this time, after the boat 217 is carried into the processing chamber 201, the pressure and temperature of the processing chamber 201 are adjusted (step S2 in FIG. 8). Next, four steps of film formation steps 1 to 4 are sequentially performed.

In the process in this embodiment, a process of supplying a precursor gas as a raw material gas to the wafer 200 in the processing chamber 201 (film forming process 1: step S3 in FIG. 8), and a process of supplying a precursor gas as a raw material gas from the processing chamber 201 gas) (film formation process 2: step S4 in FIG. 8) and a process of supplying nitrogen-containing gas to the wafer 200 in the processing chamber 201 (film formation process 3: step S5 in FIG. 8). ) and a purge step (film formation step 4: step S6 in FIG. 8) for removing nitrogen-containing gas (residual gas) from the processing chamber 201, are performed a predetermined number of times (at least once). , a film is formed on the wafer 200.

Each step will be described in detail below using FIG. 9.

(Film forming process 1)
In the film forming process 1, first, before supplying the source gas, the controller 121 calculates the flow rate of the second precursor gas to be supplied to the second gas supply line, and calculates the flow rate of the second precursor gas to be supplied to the second gas supply line at that time. 2. Obtain the secondary side pressure of the solid raw material 50b, and determine that the differential pressure between the primary side pressure of the first MFC 99 provided in the first gas supply line and the secondary side pressure of the second solid raw material 50b exceeds the control limit value of the first MFC 99. Check whether it is exceeded. Note that this confirmation may be performed not during the film forming process 1 but during step S2 in FIG.

After the above confirmation, a precursor as a processing gas is adsorbed onto the surface of the wafer 200. Specifically, the on-off valve 97 is kept open, and the first sub-heater 70a and the first piping heater 71a are heated in the first solid raw material supply line with the secondary side valve v7a and the supply valve 110a open. The first precursor gas generated by the first solid raw material 50a in the first raw material container 60a is supplied to the processing chamber 201 by the first MFC 99, and the secondary valve v7b and the supply valve 110b are supplied to the second solid raw material supply line. In the open state, while heating the second sub-heater 70b and the second piping heater 71b, the carrier gas whose flow rate is controlled by the second MFC 96 is supplied, and the second solid raw material 50b generated in the second raw material container 60b is heated. A mixed gas of a precursor gas and a carrier gas is supplied to the processing chamber 201 while being monitored by the MFM 98 . That is, a mixed gas of the first precursor gas, the second precursor gas, and the carrier gas is supplied to the processing chamber 201 .

(Film forming process 2)
In the film forming step 2, at least the on-off valve 97 is closed to stop the supply of the first precursor gas, the second precursor gas, and the carrier gas. Specifically, in the first solid raw material supply line and the second solid raw material supply line, the secondary side valve v7 is changed to the closed state. Further, the supply valve 110 may be configured to be changed to a closed state. Note that the sub-heater 70, pipe heater 71, and MFCs 96 and 99 are maintained at least in the on state until the substrate processing process is finished. Further, the valve 243 of the gas exhaust pipe 231 is kept open, and the processing furnace 202 is evacuated to 20 Pa or less by the vacuum pump 246, and the residual mixed gas is removed from the processing chamber 201. Furthermore, at this time, if an inert gas, for example N ₂ gas used as a carrier gas, is supplied to the processing furnace 202, the effect of removing the residual raw material gas is further enhanced.

(Film forming process 3)
In the film forming step 3, an oxygen-containing gas is flowed as a reaction gas. Specifically, the valve v3 provided in the branch pipe 82a of the first gas supply pipe 310 is opened, and the valve v4 provided in the branch pipe 82b is closed, and oxygen containing gas whose flow rate is adjusted by the MFC 84a is supplied from the first gas supply pipe 310. Gas is supplied to the processing chamber 201 from the first gas supply hole 410a of the first nozzle 410 and exhausted from the gas exhaust pipe 231. By supplying the oxygen-containing gas, the film on the wafer 200 reacts with the oxygen-containing gas, and an oxide film is formed on the wafer 200.

Note that when flowing a nitrogen-containing gas as the reaction gas, open the valve v1 provided on the branch pipe 72a of the second gas supply pipe 320, close the valve v2 provided on the branch pipe 72b, and then The nitrogen-containing gas whose flow rate is adjusted by the MFC 74a is supplied to the processing chamber 201 from the second gas supply hole 420a of the second nozzle 420, and is exhausted from the gas exhaust pipe 231. By supplying the nitrogen-containing gas, the film on the wafer 200 reacts with the nitrogen-containing gas, and a nitride film is formed on the wafer 200. Similarly, when forming an oxynitride film, in this step, the oxygen-containing gas is supplied as a reactive gas from the first gas supply hole 410a of the first nozzle 410, and the second gas supply hole 420a of the second nozzle 420 is used as the reactive gas. The nitride-containing gas may be made to flow from each of the two. For example, the oxygen-containing gas and the nitrogen-containing gas may be supplied simultaneously, or the oxygen-containing gas and the nitrogen-containing gas may be supplied individually.

(Film forming process 4)
In the film forming step 4, after forming the oxide film, at least the valve v3 is closed, and the processing chamber 201 is evacuated by the vacuum pump 246 as an exhaust device to eliminate the oxygen-containing gas remaining after contributing to the film forming. Furthermore, at this time, if an inert gas such as N ₂ gas used as a carrier gas is supplied to the processing chamber 201, the effect of removing the remaining oxygen-containing gas from the processing chamber 201 is further enhanced.

Then, the above-described film forming steps 1 to 4 are considered as one cycle, and in step S7 in FIG. can be formed. In this embodiment, film forming steps 1 to 4 are repeated multiple times.

After the above film forming process is completed, in step S8 in FIG. 8, the pressure in the process chamber 201 is returned to normal pressure (atmospheric pressure). Specifically, for example, an inert gas such as N ₂ gas is supplied to the processing chamber 201 and exhausted. As a result, the processing chamber 201 is purged with inert gas, and gas remaining in the processing chamber 201 is removed from the processing chamber 201 (inert gas purge). Thereafter, the atmosphere in the processing chamber 201 is replaced with an inert gas (inert gas replacement), and the pressure in the processing chamber 201 is returned to normal pressure (atmospheric pressure). Then, in step S9 in FIG. 8, if the wafer 200 is carried out from the processing chamber 201, the substrate processing according to the present embodiment is completed.

In this embodiment, an MFC 99 that controls the amount of precursor gas as a source gas flowing through the supply pipe 310a, and a first gas supply line configured to be able to supply the first precursor gas to the processing chamber 201 by the MFC 99 are provided. and a second gas supply line configured to be able to supply a mixed gas of a second precursor gas and a carrier gas to the processing chamber 201, and the flow rate of the second precursor gas is equal to or lower than that of the first gas supply line. The difference between the primary side pressure of the MFC 99 (the supply pressure of the first precursor gas) provided in the MFC 99 and the secondary side pressure of the second solid raw material container 60b (the supply pressure of the mixed gas of the second precursor gas and the carrier gas) Since the controller 121 is configured to be determined based on the pressure, a plurality of raw material gases (precursor gases) can be simultaneously supplied to the processing chamber 201 regardless of their vapor pressure characteristics. Further, in this embodiment, the first precursor gas and the second precursor gas are supplied at the same time, but if the first precursor gas and the second precursor gas are supplied at least partially at the same time, the main It goes without saying that disclosure is applicable.

Furthermore, in this embodiment, if the difference between the primary side pressure of the MFC 99 and the pressure on the downstream side of the second solid raw material 50b is large, an inert gas may be supplied to the secondary side of the first MFC 99. As a result, the controller 121 can suppress the influence of thermal expansion by reducing the differential pressure (primary side pressure P1 - secondary side pressure P2) so that the control limit value of the MFC 99 is not exceeded. This makes it possible to suppress resolidification (or reliquefaction) of

Note that the first solid raw material 50a and the second solid raw material 50b are preferably the same chloride, carbide, oxide, or fluoride, respectively. Thereby, the precursor gases generated by sublimating the respective solid raw materials can be mixed and supplied to the processing chamber 201.

Next, an example of a film forming process (processing corresponding to steps S3 to S6 in FIG. 8) will be described using FIG. 10. As described above, the wafers 200 are loaded onto the boat 217 and carried into the processing chamber 201. At this time, after the boat 217 is carried into the processing chamber 201, the pressure and temperature of the processing chamber 201 are adjusted. These steps are the same as step S1 and step S2 in FIG.

(Film forming process 1)
A precursor as a source gas is adsorbed onto the surface of the wafer 200 . Specifically, the on-off valve 97 is kept open, and the first sub-heater 70a and the first piping heater 71a are heated in the first solid raw material supply line with the secondary side valve v7a and the supply valve 110a open. The first precursor gas generated from the first solid raw material 50a in the first raw material container 60a is supplied to the processing chamber 201 by the MFC 99.

(Film forming process 2)
In the film forming step 2, at least the on-off valve 97 is closed to stop the supply of the first precursor gas. Specifically, in the first solid raw material supply line, the secondary valve v7a is changed to the closed state. Further, the supply valve 110a may be configured to be changed to a closed state. Note that the first sub-heater 70a, the first pipe heater 71a, and the MFCs 96 and 99 are maintained at least in the on state until the substrate processing process is finished. Further, the valve 243 of the gas exhaust pipe 231 is kept open, and the processing furnace 202 is evacuated to 20 Pa or less by the vacuum pump 246, and the residual mixed gas is removed from the processing chamber 201. Furthermore, at this time, if an inert gas, for example N ₂ gas used as a carrier gas, is supplied to the processing furnace 202, the effect of removing the residual raw material gas is further enhanced.

(Film forming process 3)
In the film forming step 3, an oxygen-containing gas is flowed as a reaction gas. Specifically, the valve v3 provided in the branch pipe 82a of the first gas supply pipe 310 is opened, and the valve v4 provided in the branch pipe 82b is closed, and oxygen containing gas whose flow rate is adjusted by the MFC 84a is supplied from the first gas supply pipe 310. Gas is supplied to the processing chamber 201 from the first gas supply hole 410a of the first nozzle 410 and exhausted from the gas exhaust pipe 231. By supplying the oxygen-containing gas, the film on the wafer 200 reacts with the oxygen-containing gas, and an oxide film is formed on the wafer 200.

(Film forming process 4)
In the film forming step 4, after forming the nitride film, at least the valve v3 is closed, and the processing chamber 201 is evacuated using the vacuum pump 246 as an evacuation device to eliminate the nitrogen-containing gas remaining after contributing to the film forming. Furthermore, at this time, if an inert gas, for example N ₂ gas used as a carrier gas, is supplied to the processing chamber 201, the effect of removing the remaining nitrogen-containing gas from the processing chamber 201 is further enhanced.

(Film forming process 5)
A second precursor gas is adsorbed onto the surface of the wafer 200. Specifically, in the second solid raw material supply line, with the secondary side valve v7b and the supply valve 110b open, the carrier gas whose flow rate is controlled by the second MFC 96 is heated while the second sub-heater 70b and the second piping heater 71b are heated. is supplied to the processing chamber 201 while monitoring the mixed gas of the second precursor gas and carrier gas generated by the second solid raw material 50b in the second raw material container 60b with the MFM 98. That is, a mixed gas of the second precursor gas and carrier gas is supplied to the processing chamber 201.

(Film forming process 6)
In the film forming step 6, at least the on-off valve 97 is closed to stop the supply of the mixed gas of the second precursor gas and the carrier gas. Specifically, in the second solid raw material supply line, the secondary valve v7b is changed to the closed state. Further, the supply valve 110b may be configured to be changed to the closed state. Note that the second sub-heater 70b, second pipe heater 71b, MFC96, and MFM98 are maintained at least in the on state until the substrate processing process is finished. Further, the valve 243 of the gas exhaust pipe 231 is left open, and the processing furnace 202 is evacuated to 20 Pa or less using the vacuum pump 246 to remove the residual mixed gas from the processing chamber 201. Furthermore, at this time, if an inert gas, for example N ₂ gas used as a carrier gas, is supplied to the processing furnace 202, the effect of removing the residual raw material gas is further enhanced.

(Film formation process 7) (Film formation process 8)
Since these steps are exactly the same as the film formation process 3 and the film formation process 4, their explanations will be omitted.

Then, the above-mentioned film forming steps 1 to 8 are considered as one cycle, and in step S7 in FIG. can be formed. In this embodiment, film forming steps 1 to 8 are repeated multiple times. Furthermore, the present invention is not limited to this embodiment, and the cycles of film forming steps 1 to 4 may be performed a predetermined number of times, and the cycles of film forming steps 5 to 8 may be performed a predetermined number of times.

After the above film forming process is completed, in step S8 in FIG. 8, the pressure in the process chamber 201 is returned to normal pressure (atmospheric pressure). Specifically, for example, an inert gas such as N ₂ gas is supplied to the processing chamber 201 and exhausted. As a result, the processing chamber 201 is purged with inert gas, and gas remaining in the processing chamber 201 is removed from the processing chamber 201 (inert gas purge). Thereafter, the atmosphere in the processing chamber 201 is replaced with an inert gas (inert gas replacement), and the pressure in the processing chamber 201 is returned to normal pressure (atmospheric pressure). Then, in step S9 in FIG. 8, if the wafer 200 is carried out from the processing chamber 201, the substrate processing according to the present embodiment is completed.

(Flow rate control of second solid raw material supply line)
In this embodiment, since the first solid raw material 50a and the second solid raw material 50b have a system configuration that includes a plurality of solid raw materials with different vapor pressure characteristics, for example, the first solid raw material 50a having a relatively high vapor pressure is Heating by the subheater promotes the sublimation reaction, and the flow rate can be controlled by the MFC 99. On the other hand, the second solid raw material 50b, which has an extremely low vapor pressure, supplies a carrier gas for promoting sublimation in addition to the subheater described later. There must be.

For example, the first solid raw material 50a does not need to be replaced until it has sublimated to some extent due to the heating of the subheater, but on the other hand, when the amount of the second solid raw material 50b decreases, the flow rate of the second precursor gas cannot be ensured. It has to be replaced frequently. The controller 121 controls the flow rate of the second precursor gas when performing the above-described substrate processing step in order to extend the period of exchanging the second solid raw material 50b.

FIG. 11 shows a modification of the second precursor gas supply system 100b (second fixed raw material supply line). In particular, although it has the same configuration as the second precursor gas supply system 100b (second fixed raw material supply line) shown in FIG. 4, only the configuration necessary for explanation is shown in FIG. 11, and the configuration unnecessary for explanation is omitted. . The difference from the second precursor gas supply system 100b (second fixed raw material supply line) in FIG. 4 is that a dilution gas line is provided in the raw material supply pipe 330b between the MFM 98 and the second fixed raw material container 60b. The flow rate of this diluent gas is controlled by MFC95. This diluent gas is also an inert gas like the carrier gas. Note that it is preferable that the second fixed raw material 50b be heated to a sublimation temperature. Thereby, re-solidification of the second diluent gas can be suppressed.

In FIG. 12, the vertical axis is the gas flow rate, the upper horizontal axis is the remaining amount of the second solid raw material 50b, and the lower horizontal axis is time. As shown in FIG. 12, changes in the flow rate of the second precursor gas and the total flow rate of the carrier gas and diluent gas in the modified example of the second fixed raw material supply line can be seen.

By supplying this diluent gas, a mixed gas of the second precursor gas, carrier gas, and diluent gas is supplied to the processing chamber 201 from the second fixed raw material supply line in FIG. According to such a configuration, by keeping the total flow rate of the carrier gas and diluent gas constant, it is possible to suppress fluctuations in the pressure on the output side of the second solid raw material 50b. Specifically, as shown in FIG. 12, the carrier gas is increased by sublimation of the second solid raw material 50b, while the diluent gas flow rate is decreased, and the total flow rate of the carrier gas and diluent gas is kept constant. This makes it possible to eliminate the instability of the secondary side pressure in the second fixed raw material supply line due to the decrease in the second solid raw material 50b.

Furthermore, as shown in FIG. 12, with such a configuration, the flow rate of the second precursor gas supplied to the second fixed raw material supply line can be kept constant, so that the flow rate of the second precursor gas supplied to the second fixed raw material supply line can be kept constant. The confirmation based on the pressure difference between the primary side pressure of the flow rate controller provided in the flow rate controller and the secondary side pressure of the second solid material supply line may be determined only once before supplying the second precursor gas.

The constant flow rate of the diluent gas in FIG. 12 has a certain effect on the stable supply of the second precursor gas by keeping the pressure on the secondary side of the second solid raw material supply line constant; Therefore, as the carrier gas increases due to the decrease in the second solid raw material 50b, the flow rate of the diluent gas becomes zero and cannot be adjusted, and it becomes impossible to supply the second solid raw material 50b at a predetermined flow rate. This means that the second solid raw material 50b is replaced.

As shown in FIG. 13, in order to extend the exchange of the second solid raw material 50b, the set temperature of the second sub-heater 70b is increased when the flow rate of the diluent gas becomes zero or just before the flow rate becomes zero. , it was decided to encourage further sublimation of the second solid raw material 50b and readjust the total flow rate of the carrier gas and diluent gas so as to be constant again. As a result, in FIG. 12, even if there was a remaining amount of the second solid raw material 50b, it had to be replaced, but with the improvement shown in FIG. 13, it can be seen that the remaining amount of the second solid raw material 50b can be used to the limit. Here, "just before" the flow rate becomes zero refers to when the flow rate approaches zero and reaches a preset flow rate (threshold value).

In addition, after raising the set temperature and stabilizing the temperature, and before supplying the first precursor gas and the second precursor gas, check the primary side pressure of the flow rate controller provided in the first solid raw material supply line and the second solid material supply line. Confirmation may be performed based on the pressure difference on the secondary side of the raw material supply line. Thereby, the first precursor gas and the second precursor gas can be supplied simultaneously.

Note that this can also be applied to the first solid raw material 50a. For example, by understanding in advance how much heat is left in the first solid raw material 50a and setting a predetermined threshold value, the heating time of the first sub-heater 70a or the heating time of the first solid raw material container 60a, etc. When the temperature reaches the threshold value, the set temperature of the first solid raw material container 60a may be increased. Further, for example, a weight scale is installed in the first solid raw material container 60a and a predetermined threshold value is set, and when the remaining amount of the first solid raw material 50a in the first solid raw material container 60a reaches the threshold value, the first solid raw material container 60a is What is necessary is to raise the set temperature of the solid raw material container 60a.

Also, while the wrestling recipe is being executed, the controller 121 determines the total flow rate of the carrier gas and diluent gas based on the preset flow rate of the second precursor gas and the information from each pressure gauge 109, MFM 98, MFC 95, 96. can be made constant while the wafer 200 is being processed (for example, during film formation steps 1 to 4). As a result, the second precursor gas (actually, a mixed gas of the second precursor gas, carrier gas, and diluent gas) can be stably supplied at a constant flow rate, which improves the uniformity of the in-plane film thickness of the wafer 200 and the The film thickness uniformity between wafers 200 can be improved, and reproducibility can also be improved.

Further, a threshold value is set at a value where the flow rate of the diluent gas is close to zero, and after reaching this threshold value and after the end of the process recipe being executed, the set temperature of the second sub-heater 70b is increased and the temperature of the second solid raw material container 60b is increased. Increase temperature. If the flow rate of the diluent gas reaches zero during execution of the process recipe, the carrier gas is configured to have a flow rate equal to or higher than the above-described constant flow rate. However, in this case, if the first precursor gas and the second precursor gas are supplied simultaneously, the primary side pressure of the flow rate controller installed in the first solid raw material supply line and the second solid raw material are adjusted in advance before the supply. It is necessary to check the pressure difference on the secondary side of the supply line. Thereby, the process recipe being executed can be terminated.

Then, before executing the next process recipe, the set temperature of the second sub-heater 70b is raised to raise the temperature of the second solid raw material container 60b. Thereby, sublimation of the second solid raw material 50b can be promoted, the total flow rate of the carrier gas and the diluent gas can be reset, and adjustment can be made by the diluent gas flow rate. Note that the controller 121 determines that if the temperature of the second solid raw material container 60b is not stable, the flow rate of the second precursor gas will not be generated stably, so that the temperature of the second solid raw material container 60b will reach the set temperature. The process recipe is previously configured so that it cannot be executed.

According to this embodiment, the raw material supply system is capable of supplying gas (precursor gas) obtained by sublimating a plurality of solid raw materials to the processing chamber 201, and the first precursor gas can be supplied to the processing chamber 201 by the MFC 99. and a second raw material supply line configured to be able to supply a second precursor gas to the processing chamber 201 while supplying a carrier gas (pressured gas), The flow rate of the second precursor gas supplied to the supply line is determined by the primary side pressure of the MFC 99 provided in the first raw material supply line and the supply pressure of the second precursor gas from the second gas supply line to the processing chamber 201. Since it is determined according to the differential pressure, the first precursor gas and the second precursor gas can be supplied to the processing chamber 201 at the same time.

Further, according to the present embodiment, the first precursor gas and the second precursor gas are each supplied with the pressure difference between the primary side pressure of the MFC 99 and the secondary side pressure of the second solid raw material container 60b within the control range of the MFC 99. Since the first precursor gas and the second precursor gas are configured to be able to be supplied, the respective flow rates of the first precursor gas and the second precursor gas can be stably supplied at preset flow rates.

Furthermore, according to the present embodiment, by keeping the total flow rate of the carrier gas and the diluent gas constant, the second precursor gas can be constantly and stably supplied. Pressure interference in the supply line can be suppressed.

Further, according to the present embodiment, the total flow rate of the carrier gas and diluent gas is maintained constant while the differential pressure between the primary side pressure of the MFC 99 and the secondary side pressure of the second raw material supply line is within the control range of the MFC 99. Before this becomes impossible, the set temperature of the second solid raw material container 60b can be raised to promote sublimation of the second solid raw material 50b. As a result, the total flow rate of the carrier gas and diluent gas can be maintained constant again, so that the flow rate of the second precursor gas can be stabilized.

Furthermore, according to the present embodiment, a plurality of raw materials with different flow rate control methods can be configured in one supply line (supply system). As a result, for example, when using two raw materials with different vapor pressure characteristics (raw material A and raw material B), it is necessary to construct a supply line (supply system) for each raw material A and raw material B, which requires modification. Time and cost can be reduced.

Furthermore, according to the present embodiment, for raw materials whose vapor pressure is so low that it is not possible to secure the flow rate for substrate processing by simply heating the raw materials, by raising the temperature in stages and using the raw materials, it is possible to The replacement cycle can be extended.

(Other embodiments)
Although the embodiments of the present disclosure have been specifically described above, the present disclosure is not limited to the embodiments described above, and various changes can be made without departing from the gist thereof.

Furthermore, although a case has been exemplified in which a plurality of solid raw materials are provided in the raw material supply system 100, the present disclosure is not limited to this. A liquid or gas source may be connected at room temperature. Further, a pressure gauge may be provided in the raw material supply pipe 330a on the upstream side of the MFC 99 to measure the supply pressure P1 of the first precursor gas from the first solid raw material container 60a. Furthermore, the MFM98 can be replaced with a densitometer IR.

Further, according to the present embodiment, the sub-heater 70 is provided so as to cover the solid raw material container 60, but is provided in a part of the solid raw material container 60 (for example, only on the lower side), and is provided inside the solid raw material container 60. It may be configured to increase the temperature, or may be provided at the upper and lower portions of the solid raw material container 60 to heat the solid raw material container 60.

As a solid raw material containing a metal element but not containing carbon (C), that is, an inorganic metal-based raw material (inorganic metal compound), hafnium tetrachloride (HfCl ₄ ) as a halogen-based raw material, or aluminum trichloride ( AlCl ₃ ) can be used. Alternatively, it may be an organometallic raw material. Further, a halogen-based raw material is a raw material containing a halogen group. The halogen group includes a chloro group, a fluoro group, a bromo group, an iodo group, and the like. That is, the halogen group includes halogen elements such as chlorine (Cl), fluorine (F), bromine (Br), and iodine (I).

As the nitrogen-containing gas, one or more of nitrous oxide ( _N2O ) gas, nitrogen monoxide (NO) gas, nitrogen dioxide ( _NO2 ) gas, ammonia ( _NH3 ) gas, etc. can be used. As the oxygen-containing gas, one or more of oxygen (O ₂ ) gas, ozone (O ₃ ) gas, etc. can be used.

Furthermore, the reactant is not limited to a nitrogen-containing gas or an oxygen-containing gas, and other types of thin films may be formed using a gas that reacts with the source to perform film processing. Furthermore, the film forming process may be performed using three or more types of processing gases.

Further, for example, in each of the above-described embodiments, a film forming process in a semiconductor device is taken as an example of the process performed by the substrate processing apparatus, but the present disclosure is not limited thereto. That is, in addition to the film forming process, the process may be a process of forming an oxide film, a nitride film, or a process of forming a film containing metal. Further, the specific content of the substrate processing is not limited, and the present invention can be suitably applied not only to film formation processing but also to other substrate processing such as annealing processing, oxidation processing, nitriding processing, diffusion processing, and lithography processing.

Furthermore, the present disclosure is applicable to other substrate processing apparatuses such as annealing processing apparatuses, oxidation processing apparatuses, nitriding processing apparatuses, exposure apparatuses, coating apparatuses, drying apparatuses, heating apparatuses, processing apparatuses using plasma, etc. It can also be suitably applied. Further, in the present disclosure, these devices may be used together.

Further, in this embodiment, a semiconductor manufacturing process has been described, but the present disclosure is not limited thereto. For example, the present disclosure can also be applied to substrate processing such as liquid crystal device manufacturing processes, solar cell manufacturing processes, light emitting device manufacturing processes, glass substrate processing processes, ceramic substrate processing processes, and conductive substrate processing processes. Applicable.

Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is also possible to add, delete, or replace some of the configurations of each embodiment with other configurations.

Further, in the above embodiment, an example is described in which _N2 gas is used as the inert gas, but the invention is not limited to this, and rare gases such as Ar gas, He gas, Ne gas, and Xe gas may also be used. good. However, in this case, it is necessary to prepare a rare gas source. Further, it is necessary to connect this rare gas source to the third raw material supply pipe 330 so as to be able to introduce the rare gas.

98 Flow rate monitor (MFM)
99 Flow controller (MFC)
121 Control unit (controller)
330 Third raw material supply section (third raw material supply pipe)

Claims (18)

A raw material supply system capable of supplying multiple raw materials to a processing chamber,
a first gas supply line configured to control the flow rate of a first precursor gas generated by a first raw material using a flow rate controller and supply the first precursor gas to the processing chamber;
a second gas supply line configured to be able to supply a second precursor gas generated from a second raw material to the processing chamber,
The flow rate of the second precursor gas is determined by the primary side pressure of the flow rate controller provided in the first gas supply line and the supply pressure of the second precursor gas from the second gas supply line to the processing chamber. a raw material supply system configured to be determined based on the differential pressure of The raw material supply system according to claim 1, wherein the differential pressure is adjusted to be within a control range of the flow rate controller. Furthermore, it has a second raw material container that stores the second raw material, and a supply pipe that supplies carrier gas to the second raw material container,
The raw material supply system according to claim 1, wherein the flow rate of the second precursor gas can be made constant by changing the flow rate of the carrier gas. Furthermore, an on-off valve for supplying the plurality of raw materials to the processing chamber is provided,
The raw material supply system according to claim 1, wherein the first gas supply line and the second gas supply line are connected immediately before the on-off valve. Furthermore, a flow rate monitor is provided downstream of the second raw material container,
The raw material supply system according to claim 3, wherein the flow rate monitor detects the flow rate of the mixed gas of the second precursor gas and the carrier gas. The raw material supply system according to claim 1, wherein the first raw material and the second raw material are each solid at room temperature. The first raw material container in which the first raw material is placed,
comprising a first heater that heats the first raw material,
The raw material supply system according to claim 1, wherein the raw material supply system is configured to be controllable so that the temperature becomes equal to or higher than the sublimation temperature of the first raw material by heating by the first heater. Furthermore, it has a first raw material supply pipe that supplies the first raw material and a first pipe heater that heats the flow rate controller,
2. The raw material supply system according to claim 1, wherein the first pipe heater is configured to heat the first raw material supply pipe and the flow rate controller to a temperature equal to or higher than the sublimation temperature. The second raw material container in which the second raw material is placed,
comprising a second heater that heats the first raw material,
The raw material supply system according to claim 1, wherein the raw material supply system is configured to be controllable so that the temperature becomes equal to or higher than the sublimation temperature of the second raw material by heating by the second heater. Furthermore, it has a second raw material supply pipe that supplies the second raw material and a second pipe heater that heats the flow rate monitor,
The raw material supply system according to claim 5, wherein the second pipe heater is configured to heat the second raw material supply pipe and the flow rate monitor to at least the sublimation temperature or higher. The raw material supply system according to claim 1, wherein the second raw material has a lower vapor pressure than the first raw material. Furthermore, connecting piping for supplying dilution gas to the secondary side of the second raw material container,
10. The raw material supply system according to claim 9, wherein the raw material supply system is configured to sublimate the second raw material based on the temperature of the second raw material container while keeping the total flow rate of the carrier gas and the diluent gas constant. 13. The flow rate of the carrier gas is increased and the flow rate of the diluent gas is decreased in response to a decrease in the flow rate of the gas that sublimates the second raw material in the second raw material container. raw material supply system. The raw material supply system according to claim 12, wherein the raw material supply system is configured to increase the temperature of the second raw material container when the flow rate of the diluent gas approaches zero or when the flow rate of the diluent gas is zero. The raw material supply system according to claim 14, configured to increase the temperature of a portion of the second raw material container. The raw material supply system according to claim 1, further comprising a storage unit that stores characteristic data including a control limit range of the flow rate controller. A raw material supply system capable of supplying multiple raw materials to a processing chamber,
A first gas supply line configured to control the flow rate of a first precursor gas generated by a first raw material using a flow rate controller and supply the first precursor gas to the processing chamber;
a second gas supply line configured to be able to supply a second precursor gas generated from a second raw material to the processing chamber,
The flow rate of the second precursor gas is determined by the primary side pressure of the flow rate controller provided in the first gas supply line and the supply pressure of the second precursor gas from the second gas supply line to the processing chamber. a processing device having a feedstock supply system configured to be determined based on a differential pressure of A raw material supply system capable of supplying a plurality of raw materials to a processing chamber, the first precursor gas generated from the first raw material being configured to be able to be supplied to the processing chamber by controlling the flow rate of the first precursor gas using a flow rate controller. 1 gas supply line, and a second gas supply line configured to be able to supply a second precursor gas generated from a second raw material to the processing chamber, and the flow rate of the second precursor gas is: The pressure is determined based on the pressure difference between the primary side pressure of the flow rate controller provided in the first gas supply line and the supply pressure of the second precursor gas from the second gas supply line to the processing chamber. A method for manufacturing a semiconductor device, comprising a step of supplying at least the first precursor gas and the second precursor gas to the processing chamber using a raw material supply system according to the present invention, and processing a substrate placed in the processing chamber.

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