Raw material monitoring system, processing device, gas supply method, and method for manufacturing semiconductor device

Abstract

The present disclosure provides a technology comprising: a gas supply pipe that supplies, to a processing chamber, a gas obtained by converting a raw material into a gaseous state; a container that is provided to the gas supply pipe and stores the raw material; a flow rate regulator that is provided to the gas supply pipe and regulates the flow rate of the gas; and a monitoring unit that is configured to be capable of monitoring whether or not the pressure in the container after a necessary pressure change due to vaporization of the raw material is within the operating pressure range of the flow rate regulator.

Description

Raw material monitoring system, processing apparatus, gas supply method, and method of manufacturing a semiconductor device

[0001] The present disclosure relates to a raw material monitoring system, a processing apparatus, a gas supply method, and a method of manufacturing a semiconductor device.

[0002] As an example of a processing apparatus for processing a workpiece, a semiconductor manufacturing apparatus for manufacturing a semiconductor device is known. For example, in Patent Document 1, a substrate process is performed in which a processing gas is supplied into a reaction tube and a substrate is processed under predetermined processing conditions. In recent years, due to reasons such as miniaturization of devices, various processing gases such as a gas obtained by vaporizing a liquid or a gas obtained by sublimating a solid may be required to be supplied at a predetermined flow rate.

[0003] International Publication No. 2019 / 181603

[0004] The present disclosure provides a technique that enables stable supply of a processing gas.

[0005] According to one aspect of the present disclosure, there is provided a technique including a gas supply pipe that supplies a gas obtained by converting a raw material into a gaseous state to a processing chamber, a container that is provided in the gas supply pipe and stores the raw material, a flow regulator that is provided in the gas supply pipe and adjusts the flow rate of the gas, and a monitoring unit that is configured to be able to monitor whether the pressure in the container after a pressure change due to vaporization of the raw material is within an operating pressure range of the flow regulator.

[0006] According to the present disclosure, a processing gas can be stably supplied.

[0007] This is a schematic cross-sectional view of a substrate processing furnace used in an apparatus according to one aspect of the present disclosure. This is a view taken along the line A-A in Figure 1. This is an explanatory diagram illustrating the configuration of a vaporization system according to one aspect of the present disclosure. This is an explanatory diagram illustrating a storage tank according to one aspect of the present disclosure. This is an explanatory diagram illustrating a controller according to one aspect of the present disclosure. Figure 6(a) is a cross-sectional view illustrating the raw materials and raw material gas in a storage tank according to one aspect of the present disclosure. Figure 6(b) is a cross-sectional view taken along the line A-A in Figure 6(a). This is an example showing the vapor pressure characteristics of the raw materials according to one aspect of the present disclosure. Figure 8(a) is a comparative example of a storage tank according to one aspect of the present disclosure. Figure 8(b) is a simplified view of Figure 4. This is an example showing the operation of a vaporization system according to one aspect of the present disclosure. This is an example showing the effect of miniaturizing a storage tank according to one aspect of the present disclosure.

[0008] One aspect of this disclosure will be described primarily with reference to Figures 1 to 10.

[0009] Please note that the drawings used in the following explanation are all schematic, and the dimensional relationships and ratios of each element shown in the drawings do not necessarily correspond to reality. Furthermore, the dimensional relationships and ratios of each element do not necessarily correspond between multiple drawings.

[0010] Once a predetermined number of substrates 31 (hereinafter sometimes referred to as wafers) to be processed are transferred to the boat 32, which serves as a holder, the boat 32 is raised by the boat elevator 33 and inserted into the processing furnace 29. When the boat 32 is fully inserted, the processing furnace 29 is hermetically sealed by the seal cap 35, which serves as a lid. Inside the hermetically sealed processing furnace 29, the wafers 31 are heated according to the selected processing recipe, and processing gas is supplied into the processing furnace 29. The atmosphere of the processing chamber 2 is discharged from the gas exhaust pipe 66 by an exhaust device (not shown) while the wafers 31 are processed.

[0011] A reaction tube 1 is provided inside a heater 42, which is a heating device (first heating section). A manifold 44, made of stainless steel or the like, is connected to the lower end of the reaction tube 1 via an O-ring 46, which is an airtight seal. The lower end opening (furnace opening) of the manifold 44 is airtightly closed by a lid 35 via an O-ring 18, which is an airtight seal. At least the reaction tube 1, manifold 44, and lid 35 define the processing chamber 2.

[0012] A boat 32 is erected on the lid 35 via a boat support base 45, which serves as a holder for the boat 32. The lid 35 is also provided with a boat rotation mechanism 69, which rotates the boat 32 to improve the uniformity of the processing.

[0013] Two gas supply pipes (the first gas supply pipe 47 and the second gas supply pipe 48) are provided as supply routes for supplying multiple types, in this case two types, of processing gases to the processing chamber 2.

[0014] The gas supply pipe 47 is equipped with, in order from upstream, a liquid raw material unit 71, a storage unit 51, a flow rate regulator consisting of a first mass flow controller (hereinafter also referred to as MFC) 49 which is a flow rate control device (flow rate control means), and a valve 52 which is an on-off valve. Downstream of the valve 52, a first carrier gas supply pipe 53 for supplying carrier gas is joined. The carrier gas supply pipe 53 is equipped with, in order from upstream, a carrier gas source 72, an MFC 54, and a valve 55 which is an on-off valve.

[0015] A first nozzle 56 is provided at the tip of the gas supply pipe 47, extending from the bottom to the top along the inner wall of the reaction pipe 1, and a first gas supply hole 57 for supplying gas is provided on the side of the nozzle 56. The gas supply holes 57 are provided at equal pitches from the bottom to the top and each has the same opening area.

[0016] Here, the gas supply pipe 47, MFC 49, storage unit 51, and valve 52 are collectively referred to as the first gas supply unit (first gas supply line). The nozzle 56 may also be included in the first gas supply unit. Furthermore, the liquid raw material unit 71 and carrier gas source 72 may also be included in the first gas supply unit. This first gas supply line will be described later. Note that the carrier gas supply pipe 53, MFC 54, and valve 55 are included in the first gas supply unit.

[0017] The gas supply pipe 48 is equipped with a reaction gas source 73, an MFC 58, and a valve 59 (which acts as an on / off valve) in order from upstream, and a second carrier gas supply pipe 61 (which supplies carrier gas) is joined downstream of the valve 59. The carrier gas supply pipe 61 is equipped with a carrier gas source 74, an MFC 62, and a valve 63 (which acts as an on / off valve) in order from upstream. At the tip of the gas supply pipe 48, a second nozzle 64 is provided parallel to the nozzle 56, and gas supply holes 65, which are supply holes for supplying gas, are provided on the side of the nozzle 64. The gas supply holes 65 are provided at equal pitches from the bottom to the top, and each has the same opening area.

[0018] Here, the gas supply pipe 48, MFC 58, and valve 59 are collectively referred to as the second gas supply section. The nozzle 64 may also be included in the second gas supply section. Furthermore, the reaction gas source 73 and carrier gas source 74 may also be included in the second gas supply section. Note that the carrier gas supply pipe 61, MFC 62, and valve 63 are included in the second gas supply section.

[0019] The liquid raw material supplied from the liquid raw material unit 71 merges with the carrier gas supply pipe 53 via the MFC 49, storage unit 51, and valve 52, and is then supplied to the processing chamber 2 via the nozzle 56. When supplied to the processing chamber 2, the liquid raw material (raw material gas) is supplied in a vaporized state by the vaporization system 60, which serves as a raw material monitoring system. The reaction gas supplied from the reaction gas source 73 merges with the carrier gas supply pipe 61 via the MFC 58 and valve 59, and is then supplied to the processing chamber 2 via the nozzle 64.

[0020] The processing chamber 2 is connected to a vacuum pump 68, which is an exhaust device (exhaust means), via a gas exhaust pipe 66 for exhausting gas, and is evacuated by vacuum. The valve 67, which acts as a pressure adjustment unit, is an adjustment valve that can open and close to evacuate the processing chamber 2 by vacuum and stop the vacuum evacuation, and can also adjust the pressure by adjusting the valve opening.

[0021] The controller 41, which will be described later as a control unit, is configured to process the substrate 31 by controlling various transport mechanisms such as the boat elevator 33 and the rotating mechanism 69, supply system components such as MFC 49, 54, 58 and valves 52, 55, 59, exhaust system components such as valve 67 and exhaust device 68, and components that heat the substrate 31 such as heater 42.

[0022] Next, Figure 3 is a diagram illustrating the first gas supply line, which includes a vaporization system having a storage section 51. Note that in Figure 3, the substrate 31 of the processing chamber 2 is omitted. Also, the same numbers are used for parts that are the same as in Figure 1, and explanations may be omitted.

[0023] The vaporization system includes a container 200 as a storage tank for storing raw material 216 as a liquid raw material, an air valve 207, a pressure sensor P for detecting the pressure inside the container 200 (described later), a heater provided on the outside of the side wall (not shown), a position sensor for detecting the upper limit of the raw material inside the storage container 200 (described later), a limiting section provided so as to protrude from the side wall at a position higher than the position sensor (described later), a supply port provided on the side wall for replenishing the raw material 216, a storage section 51, an MFC 49, and a controller 41 as a monitoring section that monitors whether the pressure inside the container 200 after the pressure change necessary to supply the gas (raw material 216 in gaseous form) from the MFC 49 to the processing chamber 2 is within the operating pressure range of the MFC 49. In this vaporization system, only one position sensor is provided in the container 200.

[0024] The system is configured such that raw materials are supplied from the liquid raw material unit 71 to the storage section 51 via the gas supply pipe 47 by opening and closing valve AV2. In addition, the system is configured such that vaporized raw materials are supplied from the processing chamber 2 to the storage section 51 via the gas supply pipe 47 by opening and closing air valve 207.

[0025] The raw material 216 in container 200 is heated and vaporized by heater 215. The vaporized raw material 216 then merges with the first carrier gas supply pipe 53 via air valve 207, MFC 49, and valve 52, and is further supplied to the processing chamber 2 via first nozzle 56. When the remaining amount of raw material 216 becomes low, raw material 216 is replenished from liquid raw material unit 71 to container 200 through replenishment pipe.

[0026] The pressure inside container 200 fluctuates depending on the amount of vaporized gas produced from the raw material 216. For example, when the amount of raw material 216 remaining decreases, the heat transfer area from the heater (not shown) decreases, and the amount of vaporized gas produced also decreases. In this case, the MFC 49 cannot adjust the flow rate to exceed the amount of vaporized gas produced. Therefore, when the amount of raw material 216 remaining decreases and a sufficient amount of vaporized gas cannot be obtained, the pressure inside container 200 decreases. At this time, even if liquid raw material is supplied to container 200 from the liquid raw material unit 71, a predetermined amount of gas cannot be supplied to the processing chamber 2. Therefore, the liquid volume of raw material 216 must be ensured so that the gas can be safely supplied to the processing chamber 2 without being affected by this pressure fluctuation. This pressure fluctuation will be described later.

[0027] The remaining amount of raw material 216 in container 200 can be used to calculate the cumulative flow rate supplied from MFC 49 to processing chamber 2. Based on this cumulative flow rate, the remaining amount of raw material 216 can be estimated. Therefore, when the amount of raw material decreases, it can be replenished.

[0028] The cumulative flow rate of the MFC 49 from the start of the flow of raw material 216 until time T is expressed by the following formula. Here, Q ＭＦＣ This is the measured value of MFC49 (unit: SLM).

[0029] For example, the remaining amount of raw material is calculated by subtracting the cumulative flow rate value (amount of raw material 216 vaporized) from the liquid volume up to the position sensor that detects the liquid level. In other words, not only can the raw material 216 be replenished before it is introduced into the container 200 based on the cumulative flow rate value, but a predetermined flow rate of raw material 216 can also be introduced (replenished) from the liquid raw material unit 71 into the container 200 based on the calculation of the cumulative flow rate value.

[0030] The monitoring unit 41 also maintains a preset threshold value, and by comparing the remaining amount of raw material 216 with this threshold value, it can ensure accurate replenishment of the raw material 216. This threshold value is set to a liquid volume that allows a constant flow rate (a target flow rate) to be supplied from the MFC 49 to the processing chamber 2 without being affected by the pressure drop in the container 200 when supplying from the MFC 49 to the processing chamber 2, as described above. The threshold value can be any value indicating the liquid volume, and may also be the liquid level.

[0031] When air valve 207 is closed, vaporized raw material remains between air valve 207 and valve 52. The remaining raw material stops flowing and reliquefies. To prevent this reliquefaction, air valve AV1 is opened and an inert gas is flowed through the piping between air valve 207 and MFC 49 and inside MFC 49 to purge the remaining raw material (raw material gas). For example, by heating this purge gas above its vaporization temperature using a heater (not shown), the effect of preventing reliquefaction of the raw material gas can be enhanced.

[0032] Similar to Figure 1, the monitoring unit 41 is shown in Figure 3. The monitoring unit 41 is configured to monitor the remaining amount of raw material 216, as will be described later. It is also configured to monitor the flow rate of the raw material 216 that is vaporized by the pressure measured by the pressure sensor P, as will be described later.

[0033] Next, using Figure 4, we will explain the storage tank (container) 200, which is the main part of the storage section 51, a part of the vaporization system. Figure 4 is a cross-sectional view of the container 200.

[0034] The container 200 includes a storage chamber 210 in which raw material 216 is stored, a supply port 219 provided in the side wall 201 for replenishing the raw material 216, a discharge port 220 provided in the side wall 201 for discharging the raw material that has been vaporized or sublimated in the storage chamber 210, a heater 215 embedded in the bottom 202, side wall 201 and lid 203, a sensor as a position sensor that defines the upper limit of the raw material 216, and a limiting part 218 positioned higher than the sensor to restrict the flow of raw material gas, which is the raw material 216 in gaseous form.

[0035] Here, the internal heater 215 is provided on the side 201 and the lid 203, but it may also be provided on the bottom 202. Alternatively, the heater 215 may be provided on the side of the side wall 201 where the position sensor is provided. As mentioned above, since the remaining amount of raw material 216 can be calculated from the cumulative flow rate, a sensor to detect the lower limit of raw material 216 is not provided. This configuration makes the container 200 compact. The heater 215 is provided so as to surround or cover the side wall and is configured to heat the raw material 216 to a temperature higher than the vaporization temperature. Since re-liquefaction or re-solidification of the raw material 216 can cause problems such as particles, the set temperature is set to a temperature slightly higher than the vaporization temperature with a margin to prevent this re-liquefaction or re-solidification.

[0036] Furthermore, the raw material 216 supplied from the supply port 219 is heated by a heater 215 provided on the side 201 before being released into the storage chamber 210. This allows for preheating before gasification. In addition, by using the limiting section 218 as a flow limiting section, the flow paths of the raw material and raw material gas, indicated by the arrows, can be lengthened.

[0037] The raw materials and raw material gas indicated by the arrows in Figure 4 will be explained using Figure 6. Figure 6A is a simplified version of Figure 4. Therefore, explanations of overlapping components may be omitted. As shown in Figures 6A and 6B, a limiting section 218 is provided to prevent the vaporized gas (raw material gas) from the raw material 216 from going directly to the outlet 220. The raw material gas of the raw material 216 is configured to always reach the outlet 220 through the gap between the limiting section 218 and the lid section 203. This configuration allows the raw material 216 to be sufficiently vaporized.

[0038] Furthermore, as shown in Figure 4, the container 200 has a pressure sensor P that detects the pressure inside the container 200. This allows detection of the contents of the container 200 containing the raw material 216 even when the amount of raw material 216 inside the container 200 decreases, making it possible to estimate whether the remaining amount of raw material 216 is appropriate. Specifically, by detecting the pressure inside the storage tank 200 using the pressure sensor P, it is possible to monitor whether the pressure is at a predetermined value when a predetermined raw material gas is supplied to the processing chamber 2 at a constant flow rate by the MFC 49.

[0039] Furthermore, the monitoring unit 41 is configured to stop replenishing the raw material 216 when it receives a signal from the sensor indicating that the raw material 216 has reached its upper limit. Even if the sensor shown in Figures 3 and 4 malfunctions, the system is configured to allow for immediate maintenance. The system also has a limiting unit 218 positioned higher than the sensor, which is configured to limit the flow of the raw material gas generated in the container 200. As shown in Figure 6A, the gas is configured to flow from the gas supply port 219, which is the introduction port, to the gas outlet 220, which is the discharge port, in a manner that bypasses the limiting unit 218.

[0040] Furthermore, the side portion 201 of the container 200 in which the introduction portion 219 is formed is thicker than the side wall of the container 200 in which the sensor is installed. A heater 215 is provided on the side portion 201 of the container 200 in which the introduction portion 219 is formed, and is configured to heat the raw material 216 that is delivered into the container 200. The limiting portion 218 is also heated by this heater 215, and is heated to a temperature at which the raw material 216 can be vaporized. Furthermore, a heater 215 is also embedded in the lid portion 203, and is heated to a temperature at which the raw material 216 can be vaporized, similar to the limiting portion 218.

[0041] Because of this configuration, even if the sensor malfunctions and the raw material 216 is supplied into the container 200 beyond the upper limit (sensor), there is only a tiny gap between the sensor and the limiting unit 218, so the raw material 216 is immediately heated by the limiting unit 218 and a large amount of raw material gas is generated. As a result, the pressure sensor P can detect the pressure fluctuation caused by the gasification of the raw material, and thus it can detect that a pressure abnormality has occurred in the container 200. Therefore, the monitoring unit 41 can detect the abnormality and stop the supply of raw material. In this way, even if an abnormality occurs due to a sensor malfunction, it can be detected immediately, so for example, a decrease in the operating rate of the device can be suppressed.

[0042] Without this restricting portion 218, it is impossible to detect pressure fluctuations until the raw material 216 is supplied up to the lid portion 203, that is, until it is supplied up to the discharge port 220. In short, it is impossible to detect abnormal pressure until the container 200 is filled with the raw material 216. In this case, the raw material reaches the gas supply pipe 47 or the processing chamber 2 before becoming gaseous, and particles are generated. As will be described later, if it is in the standby state, it only needs to reach the gas supply pipe 47, but if the wafer 31 is being processed, there is a risk of lot out. On the other hand, according to the present embodiment, since there is only a minute gap between the sensor and the restricting portion 218, even if it cannot be detected due to a sensor failure, heat exchange occurs when the restricting portion 218 comes into contact with the liquid raw material 216 instead of the raw material gas. And since the surface area of contact also increases, heat is absorbed from the wall surface of the restricting portion 218 in the high-temperature state, and vaporization of the liquid raw material 216 is promoted. For this reason, the pressure inside the container 200 rapidly rises. At this time, the pressure sensor P can detect abnormal pressure by detecting this pressure fluctuation.

[0043] The outline of the control unit 41 as a controller is shown in FIG. 5. The monitoring unit 41, which is also a control unit (control means), is configured as a computer including a CPU (Central Processing Unit) 41a, a RAM (Random Access Memory) 41b, a storage device 41c, and an I / O port 41d. The RAM 41b, the storage device 41c, and the I / O port 41d are configured to be able to exchange data with the CPU 41a via an internal bus 41e. The controller 41 is configured to be connectable to an input / output device 411 configured as, for example, a touch panel, and an external storage device 412. Further, a receiving unit 413 connected to the upper device 75 via a network is provided. The receiving unit 413 can receive information of other devices from the upper device 75.

[0044] The storage device 41c is composed of, for example, flash memory, an HDD (Hard Disk Drive), etc. The storage device 41c contains, in a readable format, control programs that control the operation of the substrate processing apparatus, and process recipes that describe the procedures and conditions for substrate processing, as described later. The process recipe is a combination of steps in the substrate processing process performed in the substrate processing mode described later, which causes the controller 41 to execute and obtain predetermined results; it functions as a program. In this specification, the term "program" may include only the process recipe, only the control program, or both. The RAM 41b is configured as a memory area (work area) where programs and data read by the CPU 41a are temporarily held.

[0045] The I / O port 41d is connected to the lifting member, heater, MFC, valve, etc.

[0046] The control unit 41 is responsible for adjusting the flow rate of the MFC, opening and closing valves, adjusting the heater temperature, starting and stopping the vacuum pump, adjusting the rotation speed of the boat rotation mechanism, and controlling the lifting and lowering operation of the boat lifting mechanism.

[0047] Note that the control unit 41 may be configured not only as a dedicated computer but also as a general-purpose computer. For example, an external storage device (e.g., a semiconductor memory such as a USB memory or a memory card) 412 storing the above-described program is prepared, and the control unit 41 according to the present embodiment can be configured by installing the program in a general-purpose computer using such an external storage device 412. Note that the means for supplying a program to the computer is not limited to the case of supplying via the external storage device 412. For example, communication means such as the Internet or a dedicated line may be used to supply the program without passing through the external storage device 412. Note that the storage device 41c and the external storage device 412 are configured as computer-readable recording media. Hereinafter, these are collectively referred to simply as recording media. Note that in this specification, when the term "recording medium" is used, it may include only the storage device 41c alone, only the external storage device 412 alone, or both of them.

[0048] Next, an example of processing the substrate 31 will be described. Here, as an example of a semiconductor device manufacturing process, a cycle process of performing film processing by alternately supplying a source (raw material) gas and a reactant (reaction gas) to the processing chamber 2 will be described.

[0049] In the film formation process according to the present embodiment, a step of supplying a raw material gas to the wafer 31 in the processing chamber 2 (step 1), a step of removing the raw material gas (residual gas) from the processing chamber 2 (step 2), a step of supplying a reaction gas to the wafer 31 in the processing chamber 2 (step 3), and a step of removing the reaction gas (residual gas) from the processing chamber 2 (step 4) are performed non-simultaneously in a cycle a predetermined number of times (one or more times) to form a film on the wafer 31.

[0050] First, as described above, the wafer 31 is loaded into the boat 32 and carried into the processing chamber 2. At this time, as shown in FIG. 2, the storage unit 51 is connected to the liquid raw material unit 71. After the boat 32 is carried into the processing chamber 2, the following four steps are sequentially executed.

[0051] (Step 1) In Step 1, with heaters 42 and 215 in operation, the raw material gas and carrier gas (N2 gas) are introduced. First, valves 52, 55, and 67 are opened. The raw material gas is supplied to the storage section 51 via the gas supply pipe 47. The raw material gas is stored in the storage chamber 210 and vaporized by the heater 215. The vaporized gaseous raw material gas is flow-controlled by the MFC 49 and supplied to the gas supply pipe 47. In the gas supply pipe 47, the carrier gas (N2 gas) flow-controlled by the MFC 54 is mixed in from the carrier gas supply pipe 53. This mixed gas is supplied to the processing chamber 2 from the gas supply hole 57 of the nozzle 56 and exhausted from the gas exhaust pipe 66. As a result, a film containing the raw material elements is formed on the wafer 31.

[0052] (Step 2) In Step 2, the valve 52 of the gas supply pipe 47 and the valve 55 of the carrier supply pipe 53 are closed to stop the supply of raw material gas and carrier gas. The valve 67 of the gas exhaust pipe 66 is left open, and the processing furnace 29 is evacuated by the vacuum pump 68 to remove residual raw material gas from the processing chamber 2. At this time, supplying an inert gas, such as the N2 gas used as the carrier gas, to the processing furnace 29 further enhances the effect of removing residual raw material gas.

[0053] (Step 3) In Step 3, the reaction gas and carrier gas (N2 gas) are introduced. First, the valve 59 on the gas supply pipe 48 and the valve 63 on the carrier gas supply pipe 61 are both opened to mix the reaction gas, whose flow rate has been adjusted by the third MFC 58 from the gas supply pipe 48, with the carrier gas (N2 gas), whose flow rate has been adjusted by the MFC 62 from the carrier gas supply pipe 61. This mixture is then supplied to the processing chamber 2 through the gas supply hole 65 of the nozzle 64 and exhausted through the gas exhaust pipe 66. At this time, the temperature of the wafer 31 is the same as when the raw material gas is supplied, and the pressure in the processing chamber 2 is different from when the raw material gas is supplied. The supply of the reaction gas causes the film containing the raw material elements on the underlayer of the wafer 31 to react with the reaction gas, forming a modified film on the wafer 31.

[0054] (Step 4) In Step 4, after the film is formed, valves 59 and 63 are closed, and the processing chamber 2 is evacuated using a vacuum pump 68 to remove any reaction gases remaining after the film formation. At this time, supplying an inert gas, such as N2 gas used as a carrier gas, to the processing chamber 2 further enhances the effect of removing any remaining reaction gases from the processing chamber 2.

[0055] Furthermore, by repeating steps 1 to 4 described above as one cycle multiple times, a film of a predetermined thickness can be formed on the wafer 31.

[0056] Next, using Figure 7, the operation of the vaporization system when the raw material 216 is liquid will be explained. In the standby state (when no raw material gas is being supplied), when the liquid raw material 216 is added to the preheated container 200, the temperature of the liquid raw material 216 rises and it vaporizes to its vapor pressure. In other words, if there is sufficient heating time, the temperature of the liquid raw material 216 will rise to the temperature A of the container 200. Therefore, from the vapor pressure curve of the raw material 216, the temperature of the liquid raw material 216 is the same as the temperature A of the container 200, and as shown in Figure 7, pressure a at temperature A is obtained. While maintaining this state, the liquid raw material 216 is supplied to the container 200 up to the sensor that defines the upper limit.

[0057] On the other hand, when the raw material gas is being supplied (step 1 above), it is necessary to consider the effect of latent heat of vaporization. Latent heat of vaporization is required when the liquid raw material vaporizes, so heat energy is absorbed from the surroundings during vaporization. In other words, the liquid temperature will decrease by the amount of latent heat of vaporization relative to the flow rate of the generated raw material gas. According to the saturated vapor pressure curve of the liquid raw material 216 shown in Figure 7, the pressure detected by the pressure sensor P will be pressure b, corresponding to the liquid temperature B when it decreases. Therefore, as shown in Figure 7, the pressure will decrease by ΔP due to the latent heat of vaporization. In order to flow the raw material gas generated by vaporization at a constant flow rate, the pressure b in the container 200 after the pressure change must be within the operating range of the MFC. In this embodiment, the monitoring unit 41 monitors whether the pressure b in the container 200 after the pressure change necessary to supply the raw material gas from the MFC 49 to the processing chamber 2 is within the operating pressure range of the MFC 49. The monitoring unit 41 then stops the supply of raw material gas if the pressure in the container 200 after the pressure change necessary to supply the raw material gas is outside the operating pressure range of the MFC 49.

[0058] Here, "latent heat of vaporization" refers to the heat required to change a liquid into a gas, and is also called "heat of evaporation," "heat of vaporization," or "latent heat of vaporization." The latent heat of vaporization per mole is interpreted as the energy required for molecules to overcome the attractive forces acting between them in a liquid. In this specification, it is shown that the temperature of the heated liquid decreases when continuous vaporization occurs due to the effect of this latent heat of vaporization. The wall surface of the limiting section 218 is normally not affected by the latent heat of vaporization and is therefore at the same temperature as the set temperature of the heater 215.

[0059] Next, the miniaturization of the container 200 will be explained using Figures 8A and 8B. Figure 8B shows the same configuration as Figure 4, but in a simplified form. Figure 8A is a comparative example, showing an example where the container 200 is large. The tank (corresponding to the container 200) shown in Figure 8A has a large volume of liquid due to its large size. Therefore, the surface area of ​​the tank in contact with the liquid (corresponding to the raw material 216) is also large, and the raw material is susceptible to heat. In this case, the effect of the latent heat of vaporization L is negligible compared to the small container 200 in the present invention configuration shown in Figure 8B. On the other hand, in the container 200 shown in Figure 8B, the volume of liquid is reduced due to miniaturization, so the surface area in contact between the wall of the container 200 and the liquid raw material 216 is also reduced, and the effect of the latent heat of vaporization L becomes larger. Therefore, the pressure fluctuation due to the volume (liquid level) of the liquid raw material 216 becomes larger.

[0060] Furthermore, the miniaturization of the container 200 shown in Figure 8B (Figure 4) will be explained. The heat quantity Q is expressed as Q = mct. Here, m is the mass of the liquid, c is the specific heat, and t is the temperature change. Due to the relationship Q = mct, the temperature change t of the liquid temperature due to the latent heat of vaporization (L) is given by t = L / mc. In other words, it can be seen that the effect of the latent heat of vaporization L when a constant flow rate of raw material gas is supplied from the MFC 49 to the processing chamber 2 largely depends on the mass m of the liquid raw material 216. Also, the temperature of the liquid raw material 216 is caused by the heated container 200 (wall surface). Therefore, the amount of heat Q that the liquid raw material 216 receives from the wall surface of the container 200 is Q = qA, because the heating occurs through heat exchange over the surface area A of the container 200 in contact with the liquid raw material 216. Here, q is the amount of heat per unit area. Therefore, the relationship between heat quantity Q and latent heat of vaporization L is t = (qA - L) / mc², and furthermore, since the surface area A decreases as the liquid volume decreases, it can be seen that the small container 200 is easily affected by the latent heat of vaporization L, and that managing the liquid level is extremely important.

[0061] Since container 200 is susceptible to the effects of latent heat of vaporization L, four parameters are important in order to ensure that the MFC 49 operates or that sufficient pressure is maintained to secure the required flow rate: the mass m of the liquid, the surface area A, the liquid temperature of the raw material 216 to be replenished in container 200, and the temperature inside container 200. In the operation of the vaporization system, the liquid temperature of the replenished raw material 216 and the temperature inside container 200 are managed to be kept almost constant. As shown in the relationship t = (qA - L) / mc, it is sufficient to replenish the liquid raw material 216 so that the temperature change t is within the range without being affected by the latent heat of vaporization L of the required raw material 216. Therefore, by pre-determining the amount of liquid that can secure the pressure b after the pressure fluctuation ΔP corresponding to the temperature change t shown in Figure 7 as a threshold, and performing replenishment management using the calculation formula with the integrated flow rate in Equation 1, it is possible to manage the remaining amount of liquid raw material 216. In this embodiment, the monitoring unit 41 compares the remaining amount of liquid raw material 216 calculated from the threshold value and the integrated flow value, and also monitors whether the pressure b after the pressure fluctuation ΔP corresponding to the temperature change t due to latent heat of vaporization is within the operating range of the MFC 49, thus enabling stable operation.

[0062] Figure 9 shows an example of liquid level management in container 200 when supplying raw material gas. The upper limit of the liquid raw material 216 is managed by a small point sensor, and the lower limit (threshold) is managed by comparing it with the remaining amount of liquid raw material 216 calculated from the cumulative flow rate. A pressure sensor P is provided to detect the pressure inside container 200, and the pressure sensor P is configured to detect the pressure inside container 200 while the raw material gas is being supplied from container 200 to the processing chamber 2. In Figure 9, since an appropriate threshold (lower limit) is set in advance, a constant flow rate can be supplied from MFC 49 to the processing chamber 2 without being affected by the latent heat of vaporization L. This is also an example in which the liquid raw material 216 can be replenished so that the liquid volume is between the upper and lower limits when supplying raw material gas.

[0063] Next, the miniaturization of the container 200 in this embodiment will be explained. The components that make up the vaporization system in this embodiment include valves, MFCs, and piping, but these have become increasingly integrated, making further miniaturization difficult. Therefore, the two main factors that greatly influence the size of the vaporization container are the layout and the size of the container. With the miniaturization of the container 200 in this embodiment, the number of point sensors (position sensors) as liquid level sensors is reduced to one, making it possible to significantly reduce the size compared to conventional vaporizers.

[0064] In this embodiment, the smaller size of the container 200 allows for miniaturization of the mounted device, enabling the handling of multiple raw materials within the same footprint, as shown in Figure 10A. Furthermore, as shown in Figure 10B, there is greater flexibility in the orientation of the container 200 during installation. This increases the flexibility in layout and contributes to a smaller footprint for the gas box.

[0065] The container 200 is often made of metal components such as SUS to accommodate various raw materials, and conventional vaporizers are heavy because they are made of a solid block of metal. On the other hand, the miniaturization in this embodiment reduces the amount of material used, thus reducing the weight. Therefore, it has the effect of making the removal and installation of the vaporization container easier during equipment maintenance. Specifically, when the raw material is changed or the maximum flow rate is changed (for example, when the MFC is replaced), it is necessary to change the lower limit. In this embodiment, there is no sensor to detect the lower limit, and this can be handled by changing parameters. There is no need to change the position of the position sensor each time. In particular, if an increase in flow rate due to MFC replacement is anticipated in advance, the position sensor that detects the lower limit is used at a higher position. However, frequent replenishment of the raw material 216 leads to instability in the gas flow rate. On the other hand, in this embodiment, since there is no sensor to detect the lower limit, such instability in the gas flow rate is eliminated, and a stable supply of a constant flow rate is possible.

[0066] According to this embodiment, one or more of the following effects are achieved.

[0067] (1) The gas, whose flow rate is controlled by the MFC, can be stably supplied to the processing chamber without being affected by the latent heat of vaporization.

[0068] (2) By calculating the amount of liquid consumed using the cumulative flow rate, it becomes possible to achieve both effective utilization of liquid raw materials and stable operation simultaneously.

[0069] (3) Since the timing of raw material replenishment can be determined without using sensors, miniaturization and stable operation can be achieved simultaneously.

[0070] (4) Since it can be operated with only one small liquid level sensor, the storage tank itself can be made smaller.

[0071] (5) With this configuration, even if the sensor that defines the raw material stored in the container malfunctions, the sudden pressure fluctuation can be detected by the abnormal vaporization caused by the flow limiting section, thereby suppressing a decrease in the operating rate of the device due to the failure of the sensor.

[0072] (6) With this configuration, for example, by providing a heater inside the side or lid, the footprint of the device can be reduced.

[0073] (7) This configuration improves the maintainability of the components.

[0074] (8) With this configuration, the (liquid) raw material introduced into the storage tank 200 can be supplied at a temperature close to the vaporization temperature, thereby improving the vaporization efficiency of the (liquid) raw material.

[0075] (9) With this configuration, by providing a limiting section, the flow path can be lengthened before the raw material 216 supplied from the supply port 219 is discharged as raw material gas from the discharge port, thereby improving the vaporization efficiency of the (liquid) raw material.

[0076] Although embodiments of this disclosure have been described in detail above, this disclosure is not limited to the embodiments described above, and can be modified in various ways without departing from its essence.

[0077] The above-described embodiments illustrate an example of forming a film using a batch-type substrate processing apparatus that processes multiple substrates at once. This disclosure is not limited to the above-described embodiments and can be suitably applied, for example, to forming a film using a single-wafer substrate processing apparatus that processes one or several substrates at once. Furthermore, the above-described embodiments illustrate an example of forming a film using a substrate processing apparatus having a hot-wall type processing furnace. This disclosure is not limited to the above-described embodiments and can be suitably applied to forming a film using a substrate processing apparatus having a cold-wall type processing furnace.

[0078] For example, in the above-described embodiment, a configuration was described in which a supply port 219 for replenishing (liquid) raw materials is provided at the bottom 202 of the storage tank 200. However, the location of the supply port 219 is not limited to the bottom 202; it may also be located at the lid 203 or side 201 of the storage container 200. Also, for example, in the above-described embodiment, a configuration was described in which a rod-shaped position sensor is arranged. However, the shape of the position sensor is not limited to this.

[0079] Furthermore, in the embodiment described above, for example, the monitoring unit for monitoring raw materials and the control unit for processing substrates were described as an integrated configuration. However, this is not the only option, and the monitoring unit and the control unit may be configured as separate components.

[0080] Furthermore, while the embodiments described above used film deposition in semiconductor devices as an example of the processing performed by the processing apparatus, this disclosure is not limited thereto. That is, in addition to film deposition, the processing may also involve forming oxide films, nitride films, or metal-containing films. Moreover, the specific content of the substrate processing is not limited, and this disclosure can be suitably applied not only to film deposition but also to other substrate processing such as annealing, oxidation, nitriding, diffusion, and lithography. Furthermore, this disclosure can be suitably applied to other substrate processing apparatuses, such as annealing apparatuses, oxidation apparatuses, nitriding apparatuses, exposure apparatuses, coating apparatuses, drying apparatuses, heating apparatuses, and plasma-based processing apparatuses. In addition, this disclosure may involve a mixture of these apparatuses.

[0081] Furthermore, although the embodiments described above illustrate semiconductor manufacturing processes, they are not limited to semiconductor manufacturing processes. They may also be used in liquid raw material tanks, intermediate storage tanks, or liquid tanks built into vaporizers for storing liquids requiring high purity in the chemical industry. Examples of liquids in the chemical industry include pure water, hydrogen peroxide, ammonia water, alcohols, and organic acids.

[0082] Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations.

[0083] 41... Monitoring unit (control unit), 47... Gas supply pipe, 49... Flow regulator (MFC), 200... Container,

Claims

1. A raw material monitoring system comprising: a gas supply pipe for supplying a gaseous raw material to a processing chamber; a container provided in the gas supply pipe for storing the raw material; a flow regulator provided in the gas supply pipe for adjusting the flow rate of the gas; and a monitoring unit configured to monitor whether the pressure inside the container after the pressure change due to the vaporization of the raw material is within the operating pressure range of the flow regulator.

2. The raw material monitoring system according to claim 1, wherein the monitoring unit is configured to compare a preset threshold with the remaining amount of the raw material in the container calculated from the cumulative flow rate of the gas flowing through the flow regulator.

3. The raw material monitoring system according to claim 2, wherein the monitoring unit is configured to replenish the container with the raw material if, as a result of comparing the amount of raw material remaining with a preset threshold, the amount of raw material remaining is below the threshold.

4. The raw material monitoring system according to claim 2 or 3, wherein the preset threshold is the liquid volume.

5. The raw material monitoring system according to any one of claims 1 to 3, wherein the raw material is a liquid raw material.

6. The raw material monitoring system according to claim 1, wherein the pressure inside the container after the pressure change necessary to supply the gas is determined based on the saturated vapor pressure curve of the raw material.

7. The raw material monitoring system according to claim 1, further comprising a sensor for detecting the pressure inside the container, wherein the sensor is configured to detect the pressure inside the container while the gas is being supplied from the container to the processing chamber.

8. The raw material monitoring system according to claim 1, further comprising a sensor for detecting the upper limit of the raw material stored in the container, wherein the monitoring unit is configured to stop replenishing the raw material when the raw material reaches the upper limit.

9. The raw material monitoring system according to claim 8, further comprising a flow limiting unit positioned higher than the sensor, wherein the flow limiting unit is configured to limit the flow of the gas generated in the container.

10. The raw material monitoring system according to claim 8, further comprising an introduction section into which the raw material is introduced, wherein the side wall of the container in which the introduction section is formed is thicker than the side wall of the container on which the sensor is provided.

11. The raw material monitoring system according to claim 10, further comprising a discharge section from which the raw material is discharged, wherein the raw material is configured to flow from the introduction section to the discharge section so as to bypass the flow limiting section.

12. The raw material monitoring system according to claim 10, wherein a heating section is provided on the side wall of the container in which the introduction section is formed, and the raw material being delivered into the container is configured to heat the raw material.

13. The raw material monitoring system according to claim 1, wherein the monitoring unit is configured to stop supplying the raw material if the pressure inside the container after a pressure change necessary for supplying the gas is outside the operating pressure range of the flow regulator.

14. The raw material monitoring system according to claim 1, further comprising a sensor for detecting the upper limit of the raw material stored in the container, wherein the remaining amount of the raw material is expressed as the difference between the liquid volume corresponding to the upper limit determined by the sensor and the liquid volume calculated by the cumulative flow rate of the flow regulator.

15. A processing apparatus comprising a raw material monitoring system having: a gas supply pipe for supplying a gaseous raw material to a processing chamber; a container provided in the gas supply pipe for storing the raw material; a flow regulator provided in the gas supply pipe for adjusting the flow rate of the gas; and a monitoring unit configured to monitor whether the pressure inside the container after a pressure change due to the vaporization of the raw material is within the operating pressure range of the flow regulator.

16. A gas supply method comprising the step of introducing the gas into a processing chamber via a raw material monitoring system having: a gas supply pipe for supplying a gaseous raw material to a processing chamber; a container provided in the gas supply pipe for storing the raw material; a flow regulator provided in the gas supply pipe for adjusting the flow rate of the gas; and a monitoring unit configured to monitor whether the pressure inside the container after a pressure change due to the vaporization of the raw material is within the operating pressure range of the flow regulator.

17. A method for manufacturing a semiconductor device, comprising the step of supplying the raw material gas to a substrate containing a semiconductor using the gas supply method described in claim 16 and performing a predetermined process.

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