Automatic pressure control device, film deposition apparatus, and pressure control method

Abstract

To perform pressure control by facilitating gas replacement in an exhaust pipe and suppressing an influence of adhesion of a by-product.SOLUTION: An automatic pressure control device comprises a butterfly valve which has a valve body which is rotatably attached via a shaft to an annular valve seat whose inner wall surface forms a portion of an exhaust path and which changes an opening area of the exhaust path by being arranged in an inclined manner by changing an inclination angle with respect to a lateral cross section, and which controls a pressure in a processing container by changing the inclination angle of the valve body on the basis of a detection result of a pressure in the processing container. The valve body is configured such that a first tapered surface is formed in a region located on an end on a downstream side when being arranged in an inclined manner on the surface, a second tapered surface is formed in a region located on an end on an upstream side when being arranged in an inclined manner on a back surface, and an angle formed by a region excluding the first tapered surface of the surface and the first tapered surface and an angle formed by a region excluding the second tapered surface of the back surface and the second tapered surface are respectively greater than 95 degrees and equal to or less than 150 degrees.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to an automatic pressure control device, a film forming device, and a pressure control method.

Background Art

[0002] In a semiconductor device manufacturing process, for example, a raw material gas or a reaction gas is supplied into a processing container adjusted to a vacuum state, and a film forming process is performed on a semiconductor wafer (hereinafter referred to as a wafer) as a substrate. Patent Document 1 describes a vacuum pressure control device that controls the pressure in a vacuum chamber by a non-sealed butterfly valve provided in a pipe when evacuating the vacuum chamber and adjusting the pressure in the vacuum chamber in a film forming technique on a wafer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique for promoting gas replacement in an exhaust pipe and suppressing the influence of adhesion of by-products to perform pressure control.

Means for Solving the Problems

[0005] The automatic pressure control device of the present disclosure is an automatic pressure control device that controls the pressure in a processing container to which a source gas for film formation is supplied to a substrate, a vacuum exhaust unit for evacuating the gas in the processing container, an exhaust path connecting the processing container and the vacuum exhaust unit, A butterfly valve having an annular valve seat whose inner wall surface forms part of the exhaust passage, and a valve body configured as a plate-like body for blocking at least part of the cross-section that crosses the annular valve seat, and rotatably mounted to the valve seat via a shaft, and changing the opening area of ​​the exhaust passage by changing the angle of inclination of the valve body with respect to the cross-section via the shaft, wherein the pressure inside the processing container is controlled by changing the angle of inclination of the valve body based on the detection result of the pressure inside the processing container, Equipped with, When viewed from the upstream side in the gas flow direction within the exhaust passage, the upstream surface of the valve body is called the front surface and the downstream surface is called the back surface. On the front surface of the valve body, a first tapered surface is formed in the region located at the downstream end in the flow direction when the valve body is inclined, and on the back surface of the valve body, a second tapered surface is formed in the region located at the upstream end in the flow direction when the valve body is inclined. The valve body, when in the inclined arrangement, is used within the range of an inclination angle of 10 to 30 degrees, and the angle between the region of the surface excluding the first tapered surface and the first tapered surface, and the angle between the region of the back surface excluding the second tapered surface and the second tapered surface, are each greater than 95 degrees and 150 degrees or less. The butterfly valve is configured as a leak-type butterfly valve in which a gap is formed between the inner circumference of the valve seat and the outer circumference of the valve body when the inclination angle is 0 degrees and the valve is fully closed. The width of the gap is 0.1 mm or more and less than 1 mm. [Effects of the Invention]

[0006] According to this disclosure, it is possible to control the pressure while promoting gas replacement in the exhaust pipe and suppressing the effects of by-product adhesion. [Brief explanation of the drawing]

[0007] [Figure 1] This is a longitudinal cross-sectional side view of a film deposition apparatus according to an embodiment of the present disclosure. [Figure 2] A longitudinal cross-sectional side view showing the APC valve of the aforementioned film deposition apparatus. [Figure 3A] This is a cross-sectional view illustrating the valve body and exhaust flow according to the first comparative embodiment of the APC valve. [Figure 3B] This is a cross-sectional view illustrating a valve body and exhaust flow according to a second comparative embodiment. [Figure 4] This is a cross-sectional view showing the valve body in this disclosure. [Figure 5] This is a cross-sectional view illustrating the exhaust flow in the intermediate exhaust passage in this disclosure. [Figure 6] This is a cross-sectional view showing the valve body according to a modified example. [Figure 7] This graph shows the relationship between the inclination angle of the valve body and the pressure inside the processing container. [Figure 8A] This is a photograph showing the results of the evaluation test related to the example. [Figure 8B] This is a photograph showing the results of the evaluation test related to the example. [Figure 9A] This is a photograph showing the results of the evaluation test related to the comparative example. [Figure 9B] This is a photograph showing the results of the evaluation test related to the comparative example. [Figure 9C] This is a photograph showing the results of the evaluation test related to the comparative example. [Modes for carrying out the invention]

[0008] A single-wafer film deposition apparatus, which is one embodiment of the apparatus for depositing a film on a wafer W according to this disclosure (hereinafter referred to as the "film deposition apparatus"), will be described with reference to Figure 1. The film deposition apparatus 1 comprises a processing container 10 for housing a substrate, such as a wafer W, and a control unit 100. The control unit 100 consists of, for example, a computer and has a data processing unit including a program, memory, and CPU. The program incorporates commands that send control signals from the control unit 100 to each part of the film deposition apparatus 1 and advance each process related to film deposition (film deposition process). The program is stored in a computer storage medium, such as a flexible disk, compact disk, hard disk, MO (magneto-optical disk), non-volatile memory, etc., and installed in the control unit 100. The control unit 100 controls and operates each of the components in the film deposition apparatus 1, which will be described later, according to the operation by the operator and a predetermined program.

[0009] The processing container 10 is formed in a substantially cylindrical shape from a metal such as aluminum (Al). A carry-in / out port 61 for carrying in or out the wafer W is formed in a side wall of the processing container 10 so as to be openable and closable by a gate valve 62. Inside the processing container 10, a mounting table 63 for horizontally supporting the wafer W is provided. The mounting table 63 is formed in a disc shape from a ceramic material such as aluminum nitride (AlN), or a metal material such as aluminum or nickel alloy. In this example, a substrate heater 64 serving as a heating unit for heating the wafer W to a temperature within a range of about 300°C to 500°C is embedded in the mounting table 63. The outer peripheral region and the side surface of the upper surface of the mounting table 63 are covered by a cover member 65 formed from a ceramic such as alumina.

[0010] The mounting table 63 is connected via a support member 66 to a lifting mechanism 67 provided below the processing container 10, and is configured to be movable up and down between a processing position shown in FIG. 1 and a transfer position of the wafer W indicated by a one-dot chain line below. In FIG. 1, reference numeral 10a denotes a partitioning member for vertically partitioning the inside of the processing container 10 when the mounting table 63 ascends to the processing position. Below the mounting table 63 inside the processing container 10, three (only two are shown) support pins 68 are provided so as to be movable up and down by a pin lifting mechanism 69 provided below the processing container 10. The support pins 68 are inserted into through holes 63a of the mounting table 63 at the transfer position and are configured to project and retract with respect to the upper surface of the mounting table 63, and are used for transferring the wafer W between an external transfer mechanism (not shown) and the mounting table 63. In the figure, reference numeral 71 denotes a bellows that partitions the atmosphere inside the processing container 10 from the outside air and expands and contracts in accordance with the lifting operations of the mounting table 63 and the support pins 68, respectively.

[0011] A shower head 76 for supplying a processing gas in a shower shape into the processing container 10 is provided in the processing container 10 so as to face the mounting table 63. The shower head 76 includes a main body portion 77 fixed to the top wall 10b of the processing container 10 and a shower plate 78 connected below the main body portion 77, and its interior forms a gas diffusion space 79. An annular protrusion 78a protruding downward is formed at the peripheral edge of the shower plate 78, and gas discharge holes 78b are formed on the flat surface inside the annular protrusion 78a. The gas supply mechanism 40 is connected to the gas diffusion space 79 through a gas introduction hole 81.

[0012] The gas supply mechanism 40 includes a source gas supply unit 41 configured to supply a source gas containing a raw material of a film formed on the wafer W to the processing container 10, a reaction gas supply unit 42 configured to supply a reaction gas that reacts with the source gas, and purge gas supply units 43 and 44 configured to supply a purge gas. The source gas supply unit 41 includes a source gas supply source 45 and a supply path 46. A flow rate adjustment unit 47, a storage tank 48, and a valve 49 are provided in the supply path 46 from the upstream side.

[0013] Similar to the source gas supply unit 41, the reaction gas supply unit 42 includes a reaction gas supply source 51 and a supply path 52, and a flow rate adjustment unit 53, a storage tank 54, and a valve 55 are provided in the supply path 52 from the upstream side. The purge gas supply units 43 and 44 each include a purge gas supply source 56 and a supply path 57, and a flow path adjustment unit 58 and a valve 59 are provided in each supply path 57. The supply path 57 of one of the purge gas supply units 43 is connected to the source gas supply path 46 to purge the source gas, and the supply path 57 of the other purge gas supply unit 44 is connected to the reaction gas supply path 52 to purge the reaction gas.

[0014] The following explanation will use the case of depositing a hafnium oxide (HfO2) film on a wafer W as an example. In this case, the source gas is a hafnium (Hf)-based gas, specifically a gas containing cyclopentadienyltris(dimethylamino)hafnium (CpHf(NMe2)3). The reaction gas is an oxygen-based gas, specifically a gas containing ozone (O3). The purge gas is, for example, a nitrogen (N)-based gas, specifically a gas containing nitrogen (N2). The above configuration included in the gas supply mechanism 40 is controlled by the control unit 100.

[0015] An annular exhaust duct 84, for example, with a rectangular cross-section, is positioned on the upper part of the side wall of the processing container 10. A slit 85 is provided along the inner circumference of the exhaust duct 84, and an exhaust port 86 is formed on the outer wall of the exhaust duct 84. A top wall 10b is provided on the upper surface of the exhaust duct 84 via an insulating member 87 to close the upper opening of the processing container 10, and the space between the exhaust duct 84 and the insulating member 87 is airtightly sealed with a seal ring 88.

[0016] The film deposition apparatus 1 is equipped with an automatic pressure control mechanism (automatic pressure control device) 2 that performs exhaust and pressure adjustment in the processing container 10. The automatic pressure control mechanism 2 includes a vacuum exhaust unit 11 that evacuates the gas from inside the processing container 10, a pressure detection unit 12 that detects the pressure inside the processing container 10, an APC valve (Auto pressure Controller Valve) 3, a shut valve 14 that opens and closes the exhaust passage 16, and an exhaust pipe 15 that connects these to the exhaust duct 84.

[0017] The exhaust pipe 15 forms an exhaust passage 16 through which the gas discharged from the exhaust duct 84 flows as an exhaust stream via the exhaust port 86. The cross-sectional shape of the exhaust pipe 15 and the exhaust passage 16 is, for example, a circle. The exhaust passage 16 is connected in the following order: the exhaust port 86 of the exhaust duct 84, the pressure detection unit 12, the APC valve 3, the shut valve 14, and the vacuum exhaust unit 11. The pressure detection unit 12 is located in particular immediately adjacent to the exhaust port 86. As a result, the pressure detected by the pressure detection unit 12 can be considered as the pressure detected inside the processing container 10.

[0018] The vacuum exhaust section 11 is comprised of a vacuum pump, such as a dry pump. The shut valve 14 is located upstream of the vacuum exhaust section 11 and is configured to open and close the exhaust passage 16. The shut valve 14 is used to close the exhaust passage 16.

[0019] Figure 2(a) is a longitudinal side view of the APC valve 3, and (b) is a cross-sectional view taken along line B-B' in (a). The APC valve 3 consists of, for example, a leak-type butterfly valve and comprises a drive mechanism 4 and a valve mechanism 5. The drive mechanism 4 includes a controller (not shown), a motor 6, and a shaft 7. The motor 6 includes a drive unit, a driver, an encoder, and a rotating shaft (all not shown). The rotating shaft is rotated by the drive unit. The pressure detection unit 12 and the driver of the motor 6 are connected to the controller. The controller acquires target pressure information from the control unit 100. The controller stores the rotation angle of the rotating shaft as an operable variable associated with, for example, the difference between the target pressure and the pressure detected by the pressure detection unit 12. The driver of the motor 6 controls the rotation angle of the drive unit based on the rotation angle output from the controller according to the detection result of the pressure detection unit 12, thereby controlling the processing container 10 to an arbitrary target pressure.

[0020] The base end of shaft 7 is connected to the rotating shaft of motor 6 so that their central axes coincide. The rotating shaft of motor 6 rotates around its central axis L, causing shaft 7 to rotate around its central axis L. Hereafter, the central axis L of the rotating shaft will be referred to as the rotation axis L of shaft 7. The tip end of shaft 7 is located inside the valve mechanism 5.

[0021] The valve mechanism 5 includes a valve seat 20 having an annular body and being attached to the exhaust pipe 15, and a valve body 30 provided inside the valve seat 20. The valve mechanism 5 is made of, for example, stainless steel. The valve seat 20 is interposed in the middle portion of the exhaust pipe 15. The area inside the inner wall surface 21 of the body of the valve seat 20 forms a cylindrical internal space and forms an intermediate exhaust passage 22 connecting the exhaust passages 16 upstream and downstream of the valve seat 20. Exhaust flow flows in generally uniformly from the exhaust pipe 15 upstream of the APC valve 3 to the upstream end of the intermediate exhaust passage 22. A valve seat heater 25 is embedded in the valve seat 20, raising the inner wall surface 21 of the valve seat 20 to approximately 200°C.

[0022] For the sake of explanation, the XYZ Cartesian coordinate system will be used in the description of the APC valve 3 in this specification. As shown in Figures 2(a) and (b), the direction from the upstream side to the downstream side of the APC valve 3 is called "direction Y". The flow direction of the exhaust flow entering the intermediate exhaust passage 22 is parallel to direction Y. One direction perpendicular to direction Y is called "direction X", and the direction perpendicular to both direction Y and direction X is called "direction Z". The tip of the shaft 7 is provided through the portion of the valve seat 20 that extends radially from the center of the internal space.

[0023] The valve body 30 is made of a plate-shaped member and is installed in the internal space of the valve seat 20. Specifically, the valve body 30 is disc-shaped and can block at least a portion of the annular cross-section that crosses the valve seat 20. The valve body 30 may also be elliptical or rectangular in shape, in which case the cross-sections of the valve seat 20 and the exhaust passage 16 will also be elliptical or rectangular.

[0024] Viewed from the upstream side of the exhaust passage 16, the valve body 30 has an upstream surface 31 and a downstream surface 32, and an annular side surface 33 between the surface 31 and the back surface 32. The valve body 30 is attached to the tip side of the shaft 7 such that the extension of the shaft 7 is aligned along the diametrical direction of the valve body 30. That is, the central axis of the valve body 30 is the same as the rotation axis L of the shaft 7, and when the shaft 7 is rotated, the valve body 30 rotates around the rotation axis L. By rotating around the rotation axis L, the valve body 30 changes the inclination angle with respect to the cross-section of the valve seat 20.

[0025] As shown by the solid lines in Figures 2(a) and (b), when the inclination angle of the valve body 30 is zero degrees, the front surface 31 and back surface 32 of the valve body 30 are arranged parallel to the cross-section of the valve seat 20, completely closing the intermediate exhaust passage 22 of the valve seat 20. When fully closed, a gap is formed between the side surface 33 of the valve body 30 and the inner wall surface 21 of the valve seat 20. In this example, the APC valve 3 is configured as a leak-type butterfly valve, as a gap is formed between the valve body 30 and the valve seat even when fully closed. In the leak-type APC valve 3, the opening area of ​​the intermediate exhaust passage 22 when the valve body 30 is fully closed is the area of ​​the gap between the inner wall surface 21 of the valve seat 20 and the side surface 33 of the valve body 30. When the inclination angle of the valve body 30 is zero degrees, the conductance of the intermediate exhaust passage 22 is smallest.

[0026] As shown by the dashed line in Figure 2, when the inclination angle of the valve body 30 is, for example, 90 degrees, the front surface 31 and back surface 32 of the valve body 30 are positioned perpendicular to the cross-section of the valve seat 20, resulting in a fully open intermediate exhaust passage 22. When fully open, almost the entire intermediate exhaust passage 22 becomes the opening area. When the inclination angle of the valve body 30 is 90 degrees, the conductance of the intermediate exhaust passage 22 is at its largest.

[0027] As described above, the APC valve 3 controls the pressure inside the processing container 10 by changing the amount of exhaust from the processing container 10 through a change in the opening area of ​​the intermediate exhaust passage 22 according to the inclination angle of the valve body 30. For example, the automatic pressure control mechanism 2 adjusts the pressure inside the processing container 10 to a range of, for example, 133 Pa (1 torr) to 400 Pa (3 torr) before starting the film deposition process in the film deposition apparatus 1. In this case, the automatic pressure control mechanism 2 is configured so that the inclination angle of the valve body 30 of the APC valve 3 can be changed within a range of, for example, 10 to 30 degrees. After that, the film deposition process described below may be started after fixing the inclination angle of the valve body 30 after the pressure adjustment while continuously exhausting by the vacuum exhaust section 11. Alternatively, pressure control to adjust the pressure inside the processing container 10 may be continued during the film deposition process.

[0028] In the film deposition process of the film deposition apparatus 1, film deposition is performed, for example, by the ALD (Atomic Layer Deposition) method. In the ALD method, a first film deposition process in which source gas is supplied, a second film deposition process in which reaction gas is supplied, and a purging process in which only purging gas is supplied after these processes are repeatedly performed. The gas supplied into the processing container 10 in each process is sequentially flowed into the exhaust passage 16 of the automatic pressure control mechanism 2. In the film deposition apparatus 1, the first film deposition process, the second film deposition process, and the purging process are each completed in, for example, about 1 second, and then the process moves on to the next step. At this time, the automatic pressure control mechanism 2 is constantly exhausting the processing container 10, so the replacement of gas in the processing container 10 of the film deposition apparatus 1 is completed, but gas may remain in the exhaust passage 16 of the automatic pressure control mechanism 2, and the replacement may not be completed. In such cases, gas molecules contained in the residual source gas and reaction gas are likely to react in the exhaust passage 16 of the automatic pressure control mechanism 2, generating byproducts. As previously mentioned, when the source gas is a hafnium-based gas and the reaction gas is ozone, the by-products are hafnium oxides such as hafnium oxide (HfO2).

[0029] Such by-products tend to form in areas where gas tends to accumulate, such as stagnant areas in the exhaust flow, and in bends and narrows in the exhaust passage 16 where the exhaust flow is prone to collision. Specifically, in the automatic pressure control mechanism 2 of this example, by-products tend to form in the APC valve 3 and the shut valve 14. For this reason, the APC valve 3 has a wider opening area in the intermediate exhaust passage 22 when the valve body 30 is fully closed than that of a conventional leak-type butterfly valve. In a typical leak-type butterfly valve, the gap width between the valve body 30 and the valve seat 20 when fully closed is, for example, 0.1 mm. In contrast, the APC valve 3 of this example has the gap width between the valve body 30 and the valve seat 20 when fully closed set to, for example, 0.5 mm around the entire circumference of these components 30 and 20. The gap width between the valve body 30 and the valve seat 20 is the width dimension of the gap between the valve body 30 and the valve seat 20 as viewed along the radial direction of the valve seat 20. It is preferable that the gap width between the valve body 30 and the valve seat 20 is 0.5 mm at all positions on the outer circumference of the valve seat 20. However, even if the gap width is less than 0.5 mm in some areas on the outer circumference, the average gap may still be 0.5 mm.

[0030] In this case, the gap width between the valve body 30 and the valve seat 20 when fully closed is not limited to the above example, but may be set within the range of 0.1 mm or more and less than 1 mm, preferably within the range of 0.3 mm or more and 0.6 mm or less. This allows for the conventional leak-type valve Ta Compared to a fly valve, the exhaust flow rate at the outer circumference of the valve body 30 in the intermediate exhaust passage 22 is increased, promoting gas replacement within the exhaust passage 16 and suppressing the generation of by-products. In addition, the gap between the valve body 30 and the valve seat 20 is widened, which also has the effect of suppressing the clogging of the gap by by-products.

[0031] Furthermore, as shown in Figure 4 later, the valve body 30 of this disclosure has tapered surfaces (upstream tapered surface 36, downstream tapered surface 35) on both the surface 31 and the back surface 32. For comparison with this disclosure, the influence of the shapes of a first comparative form valve body 30A and a second comparative form valve body 30B, which have different shapes from the valve body 30, on the tendency for by-product formation will be explained (Figures 3A and 3B). Figure 3A is a cross-sectional view of the first comparative form valve body 30A, and Figure 3B is a cross-sectional view of the second comparative form valve body 30B. These cross-sectional views show the cross-section at a diametrical position perpendicular to the rotation axis L of the shaft 7 and passing through the center of the disc-shaped valve body 30. The arrows shown in Figures 3A and 3B indicate the flow of the exhaust flow, and the thickness of the arrows indicates the relative magnitudes of the flow rates of each exhaust flow. In these figures, the inclination angle of the valve bodies 30A and 30B is set to 15 degrees as an example.

[0032] As shown in Figures 3A and 3B, the valve bodies 30A and 30B are located at their ends 34A and 34B, where the diameter of the valve body 30 perpendicular to the axis of rotation L intersects with the end of the valve body 30, and are therefore furthest from the axis of rotation L. Thus, when the valve bodies 30A and 30B are inclined, these ends 34A and 34B are the furthest from the inner wall surface 21 of the valve seat 20. Looking along the circumferential direction of the valve bodies 30A and 30B, the ends of the valve bodies 30A and 30B gradually approach the inner wall surface 21 of the valve seat 20, moving from the aforementioned ends 34A and 34B towards the intersection with the axis of rotation L of the shaft 7, until they are positioned with the aforementioned 0.5 mm gap between them.

[0033] Therefore, in the inclined configuration of the valve body 30, the fluid conductance at the aforementioned ends 34A and 34B is greater than the conductance at the other end closer to the axis of rotation L. This becomes more pronounced as the inclination angle of the valve body 30 increases.

[0034] As shown in Figure 3A, the valve body 30A of the first comparative configuration has an annular downstream tapered surface 35A formed around the entire circumference of the downstream periphery, which is the periphery of the back surface 32A, which is the downstream surface. The angle between the back surface 32A and the downstream tapered surface 35A is set to, for example, 45 degrees. On the other hand, no tapered surface is formed on the upstream periphery, which is the periphery of the front surface 31, which is the upstream surface of the valve body 30A of the first comparative configuration. For the valve body 30A in this inclined configuration, of the two ends 34A that are furthest from the axis of rotation L, the one located on the upstream side is called the upstream end 37A, and the other one located on the downstream side is called the downstream end 38A.

[0035] In this case, the minimum gap width D1 between the upstream end 37A of the valve body 30A and the inner wall surface 21 of the valve seat 20 is larger than the minimum gap width D2 between the downstream end 38A of the valve body 30 and the inner wall surface 21 of the valve seat 20. For example, when the inclination angle is 15 degrees, the minimum gap width D1 is more than twice the minimum gap width D2. Therefore, the conductance at the downstream end 38A of the valve body 30 is significantly smaller than the conductance at the upstream end 37B, resulting in a flow bias between the upstream end 37A and the downstream end 38A of the valve body 30. As a result, a region is formed where the conductance is small and almost no exhaust flow occurs, making it easy for gas to remain on the upstream side of the valve body 30A.

[0036] Furthermore, when the exhaust flow that flows uniformly in from upstream of the APC valve 3 along direction Y flows along the surface 31A side of the valve body 30A, the exhaust flow toward the upstream end 37A changes direction when it reaches the surface 31A of the valve body 30A. At this time, after the direction of the exhaust flow changes along the surface 31A of the valve body 30A, when an exhaust flow toward the upstream end 37A with high conductance is formed, the direction of the flow changes at an acute angle, making it easy for stagnation to occur. In particular, at the upstream end 37A, the intermediate exhaust passage 22A is narrowed to a minimum width D1 when the side surface 33A of the valve body 30A and the inner wall surface 21 of the valve seat 20 are in close proximity, and then expanded at the downstream tapered surface 35A. From the above, the stagnation of the exhaust flow increases before the minimum width D1, and furthermore, since there is no heater provided on the valve body 30A, by-product S1 is easily generated between the side surface 33A of the valve seat and the inner wall surface 21 of the valve seat 20 in that region.

[0037] On the other hand, the gap between the downstream end 38A of the valve body 30A and the inner wall surface 21 of the valve seat 20 in the first comparative configuration is abruptly narrowed to a minimum width D2 which is less than half the minimum width D1 on the upstream end 37A side. As a result, although the exhaust flow through the gap on the downstream end 38A side is small, stagnation is likely to occur. Furthermore, this gap on the downstream end 38A side is gradually expanded from the side surface 33A to the downstream tapered surface 35A. With the formation of such an intermediate exhaust passage 22A, a denser by-product S2 is more likely to be generated in the intermediate exhaust passage 22A than by-product S1 on the upstream end 37A side.

[0038] As described above, the generated by-products S1 and S2 not only hinder the rotation of the valve body 30A and make it difficult to change the tilt angle of the valve body 30A, but may also prevent the intermediate exhaust passage 22 from closing completely. Therefore, the automatic pressure control mechanism 2 will require maintenance to remove the by-products S1 and S2 before the rotation of the valve body 30A becomes difficult.

[0039] The problem of by-product S1 and S2 adhesion described above is not limited to the valve body 30A in the first comparative configuration, which has only a downstream tapered surface 35A, as explained using Figure 3A. As shown in Figure 3B, the same problem occurs in the valve body 30B of the second comparative configuration, in which an annular upstream tapered surface 36B is formed around the entire circumference of the upstream periphery, and no tapered surface is formed on the downstream periphery. The minimum gap width E2 between the downstream end 38B of the valve body 30B and the inner wall surface 21 of the valve seat 20 is larger than the minimum gap width E1 between the upstream end 37B of the valve body 30B and the inner wall surface 21 of the valve seat 20. For example, when the inclination angle is 15 degrees, the minimum gap width E2 is more than twice the minimum gap width E1. Therefore, the conductance at the upstream end 37B of the valve body 30B is significantly smaller than the conductance at the downstream end 38B. Thus, because a region is formed where the conductance is small and almost no exhaust flow occurs, gas tends to remain even upstream of the valve body 30B.

[0040] Furthermore, when the exhaust flow, which flows uniformly in from the upstream of the APC valve 3 along direction Y, flows along the surface 31B side of the valve body 30B, the exhaust flow toward the downstream end 38B changes direction when it reaches the surface 31B of the valve body 30B. At this time, after the direction of the exhaust flow changes along the surface 31B of the valve body 30B, when an exhaust flow toward the downstream end 38B with high conductance is formed, the direction of the flow changes to an obtuse angle. Next, the exhaust flow passes through the intermediate exhaust passage 22A at the downstream end 38B. At the downstream end 38B, the intermediate exhaust passage 22A is constricted to a minimum width E2 as the upstream tapered surface 36B of the valve body 30B and the inner wall surface 21 of the valve seat 20 come into close proximity. After that, the gap between the side surface 33B of the valve body 30B and the inner wall surface 21 of the valve seat 20 gradually expands, making it easy for stagnation of the exhaust flow to form. From the above, the stagnation of the exhaust flow increases before reaching the minimum width E2, and furthermore, since there is no heater provided on the valve body 30B, a condition is formed in which by-products are easily generated between the side surface 33B of the valve seat and the inner wall surface 21 of the valve seat 20 in that region.

[0041] Furthermore, the gap between the upstream end 37B of the valve body 30B and the inner wall surface 21 of the valve seat 20, which is related to the second comparative configuration, is abruptly narrowed to a minimum width E1 that is less than half of the minimum width E2 on the downstream end 38B side. As a result, although the exhaust flow through the gap on the upstream end 37B side is small, stagnation is likely to occur. In addition, this gap on the upstream end 37B side narrows in stages from the upstream tapered surface 36B to the side surface 33A. With the formation of such an intermediate exhaust passage 22B, it is thought that by-products are likely to be generated in the intermediate exhaust passage 22B. And it is thought that by-products are generated in the narrowed areas at the downstream end 38B and the upstream end 37B, making it difficult for the valve body 30B to rotate.

[0042] As confirmed above in the first and second comparative forms, by-products may be generated in valve bodies 30A with a downstream tapered surface 35A formed only on the back surface 32A, and in valve bodies 30B with an upstream tapered surface 36B formed only on the front surface 31B, potentially preventing them from closing completely. This is also likely to be the case for valve bodies that do not have a downstream tapered surface 35A or an upstream tapered surface 36B.

[0043] Figure 4 shows a cross-sectional view of the valve body 30 in this embodiment. In Figure 4, the valve body 30 is shown with an inclination angle of 15 degrees as an example. The valve body 30 in this embodiment includes an upstream tapered surface 36 formed along the peripheral edge of the surface 31 of the valve body 30, a downstream tapered surface 35 formed along the peripheral edge of the back surface 32 of the valve body 30, and a side surface 33 formed between the upstream tapered surface 36 and the downstream tapered surface 35. The upstream tapered surface 36 is an annular tapered surface provided around the entire circumference of the upstream periphery, and the downstream tapered surface 35 is an annular tapered surface provided around the entire circumference of the downstream periphery.

[0044] By providing such an upstream tapered surface 36 and a downstream tapered surface 35, when the valve body 30 is inclined, the minimum gap width F2 at the downstream end 38 and the minimum gap width F1 at the upstream end 37 are approximately the same size. Furthermore, the minimum gap width F1 at the upstream end 37 can be widened to approximately the same extent as the minimum gap width D1 at the upstream end 37A in the first comparative configuration shown in Figure 3A. In addition, the minimum gap width F2 at the downstream end 38 can be widened to approximately the same extent as the minimum gap width E2 at the downstream end 38B in the second comparative configuration shown in Figure 3B.

[0045] As described above, when the valve body 30 of this embodiment is arranged at an angle, the minimum gap widths F2 and F1 at the downstream end 38 and the upstream end 37 are approximately equal to each other, and no throttling biased to one side is formed. In this case, when the exhaust flow flows along the surface 31 side of the valve body 30, as shown in Figure 5, an exhaust flow is more likely to be formed in which the flow direction changes at an obtuse angle toward the downstream end 38 than an exhaust flow in which the flow direction changes at an acute angle toward the upstream end 37. On the other hand, in the intermediate exhaust passage 22, the aforementioned minimum widths F2 and F1 are approximately the same, so there is no significant difference in conductance when the exhaust flow flows through the downstream end 38 and the upstream end 37. Therefore, the exhaust flow is less likely to experience the same flow bias as in the first and second comparative embodiments, gas is less likely to remain on the upstream side of the valve body 30 of this disclosure, and the generation of by-products is suppressed throughout the entire exhaust passage 16.

[0046] Here, the upstream tapered surface 36 and the downstream tapered surface 35 are specifically formed by chamfering at a tapered angle, such as 45 degrees, with respect to the thickness direction of the valve body 30. In other words, the upstream tapered surface 36 and the downstream tapered surface 35 are formed at an angle of 135 degrees with respect to the surface 31 or back surface 32 of the valve body 30. The intermediate exhaust passage 22 at the downstream end 38 and the upstream end 37 is abruptly narrowed by the upstream tapered surface 36, resulting in a gap of minimum width F1 and F2 at the side surface 33, and then abruptly expanded by the downstream tapered surface 35.

[0047] The exhaust flow upstream of the valve body 30, which contains the stagnant source gas and reaction gas, is prone to colliding with the upstream tapered surface 36 when it flows into the gap between the downstream end 38 or upstream end 37 of the intermediate exhaust passage 22 and the inner wall surface 21 of the valve seat 20. As a result, by-products are easily generated and grown on the upstream tapered surface 36. As the exhaust flow, with a reduced content of source gas and reaction gas that generate by-products, passes through the side surface 33 and the downstream tapered surface 35, the adhesion of by-products in these areas is suppressed. On the other hand, in the region of the inner wall surface 21 of the valve seat 20 facing the upstream tapered surface 36, the exhaust flow is less likely to collide with the upstream tapered surface 36, and the adhesion of by-products is suppressed by heating by the valve seat heater 25.

[0048] However, the minimum gap width F2 between the downstream end 38 of the valve body 30 and the inner wall surface 21 of the valve seat 20 is approximately the same as the minimum gap width F1 between the upstream end 37 and the inner wall surface 21 of the valve seat 20, but in detail, it is slightly larger than the minimum width F1. And, similar to the first and second comparative forms, when the exhaust flow flows along the surface 31 side of the valve body 30, stagnation is likely to occur in the exhaust flow toward the upstream end 37, and stagnation is less likely to occur in the exhaust flow toward the downstream end 38. For this reason, the exhaust flow rate passing through the downstream end 38 tends to be greater than the exhaust flow rate passing through the upstream end 37. Consequently, the amount of by-products generated on the upstream tapered surface 36 tends to be greater at the downstream end 38 than at the upstream end 37.

[0049] As described above, the APC valve 3 suppresses the overall generation of by-products, effectively allows the by-products to grow on the upstream tapered surface 36 to remove residual gas, and prevents by-products from adhering downstream of the APC valve 3. Therefore, by installing the APC valve 3 upstream of the shut valve 14, the adhesion of by-products to the shut valve 14 can be suppressed, and the shut valve 14 can also be prevented from becoming uncontrollable.

[0050] The taper angles of the upstream tapered surface 36 and the downstream tapered surface 35 are not limited to 45 degrees, but are greater than 5 degrees and 60 degrees or less, preferably 15 degrees or more and 45 degrees or less, and more preferably 30 degrees or more and 45 degrees or less. In other words, the angle formed by the upstream tapered surface 36 and the surface 31 of the valve body 30 and the angle formed by the downstream tapered surface 35A and the back surface 32 are not limited to 135 degrees, but are greater than 95 degrees and less than 150 degrees, preferably 105 degrees or more and 135 degrees or less, and more preferably 120 degrees or more and 135 degrees or less.

[0051] For example, when the inclination angle is between 15 and 30 degrees, and the taper angles of the upstream tapered surface 36 and the downstream tapered surface 35 are, for example, 5 degrees or more, the minimum gap width F1 at the upstream end 37 and the minimum gap width F2 at the downstream end 38 of the valve body 30 increase as the taper angle increases. Also, as the taper angle increases, the difference between the minimum gap widths F1 and F2 decreases, and the difference in conductance at the upstream end 37 and the downstream end 38 can be reduced. In particular, if the taper angles of the upstream tapered surface 36 and the downstream tapered surface 35 are 15 degrees or more, the minimum gap width F1 at the upstream end 37 and the minimum gap width F2 at the downstream end 38 of the valve body 30 become equivalent to the distance between the side surface 33 of the valve body 30 and the valve seat 20. Therefore, the minimum widths F1 and F2 increase or decrease in accordance with the increase or decrease in the tilt angle, but they are approximately the same as each other, thereby improving and homogenizing the conductance.

[0052] Furthermore, as described above, when forming the upstream tapered surface 36 and the downstream tapered surface 35 with a predetermined taper angle based on the side surface 33, setting a larger taper angle widens the upstream tapered surface 36 and the downstream tapered surface 35. This increases the gap between the valve body 30 and the valve seat 20, improving the conductance. Also, the upstream tapered surface 36 has a larger surface area for by-product adhesion, and the downstream tapered surface 35 expands the flow path, suppressing the adhesion of by-products. For these reasons, it can be said that a larger taper angle for the upstream tapered surface 36 and the downstream tapered surface 35 is preferable.

[0053] On the other hand, increasing the taper angle would result in a large cutout on the surface 31 and back surface 32 of the valve body 30 by the upstream tapered surface 36 and the downstream tapered surface 35. This could potentially affect assembly with other structures such as the shaft 7. Therefore, although it depends on the specific specifications and structure of each automatic pressure control mechanism 2, considering all factors, the taper angle of the upstream tapered surface and the downstream tapered surface 35A is suitable within the above range, and it is particularly preferable to keep it in the range of 30 degrees to 45 degrees.

[0054] Furthermore, if the taper angle is smaller than the above-mentioned preferred range (for example, 3 degrees), the upstream tapered surface 36 of the downstream end 38 and the downstream tapered surface 35A of the upstream end 37 protrude from the side surface 33 towards the valve seat 20. As a result, the minimum gap values ​​F1 and F2 become smaller, and the upstream tapered surface 36 and the downstream tapered surface 35 become narrower. Consequently, the conductance at the upstream end 37 and the conductance at the downstream end 38 become smaller, increasing residual gas and making it easier for by-products to be generated.

[0055] As described above, for the APC valve 3, the gap width between the valve body 30 and the valve seat 20 when fully closed, and the taper angles of the upstream tapered surface 36 and the downstream tapered surface 35 are set within the range described above. As a result, the gap width at the upstream end 37 and the downstream end 38 of the valve body 30 becomes larger than what is necessary to allow the valve body 30 to rotate within a tilt angle range of 10 to 30 degrees, improving conductance in a balanced manner, reducing residual gas, and suppressing the generation of by-products. In addition, the valve body 30 allows by-products to grow and be collected on the upstream tapered surface 36, suppressing the generation of by-products on the downstream side.

[0056] Furthermore, the thickness of the valve body 30 on the upstream tapered surface 36 is preferably greater than the thickness of the downstream tapered surface 35A in order to increase the amount of by-products deposited. The thickness of the side surface 33, which is the largest diameter of the valve body 30, is preferably 1 mm or less, and the smaller the better. This allows the side surface 33 to scrape off by-products that have adhered to it when the valve body 30 rotates. In addition, the contact area of ​​the exhaust flow with the side surface 33 is reduced, which prevents a decrease in the flow velocity of the exhaust flow and suppresses the adhesion of by-products to the side surface 33, allowing for wider upstream tapered surface 36 and downstream tapered surface 35, for example.

[0057] The film deposition process of the film deposition apparatus 1 is described below. First, a wafer W is loaded into the processing container 10, the gate valve 62 of the processing container 10 is closed, and the wafer W is placed in the processing container 10. Next, heating of the wafer W by the substrate heater 64 is started, and the automatic pressure control mechanism 2 is activated. For the operation of the automatic pressure control mechanism 2, a predetermined flow rate of purge gas is continuously supplied from the purge gas supply units 43 and 44, the vacuum exhaust unit 11 is made to evacuate the processing container 10, the shut valve 14 is opened, and pressure measurement by the pressure detection unit 12 is started. In accordance with this pressure measurement value and the set value of the target pressure, the valve body 30 of the APC valve 3 is adjusted from a fully closed state to a predetermined inclination angle to an inclined position. As a result, the vacuum exhaust unit 11 evacuates the inside of the processing container 10 via the exhaust passage 16, and the APC valve 3 controls the inside of the processing container 10 to approach the target pressure. When the pressure in the processing container 10 becomes almost constant, the inclination angle of the valve body 30 is fixed.

[0058] The gas supply mechanism 40 first fills the processing container 10 with purge gas by performing a purging step that supplies only purge gas, and then sequentially performs a first film deposition step that supplies source gas, a purging step, a second film deposition step that supplies reaction gas, and another purging step to form film deposition molecules on the wafer W layer by layer. For this reason, the purge gas, source gas, purge gas, and reaction gas are introduced into the processing container 10 in this order, and these gases pass sequentially through the exhaust passage 16 and are discharged by the vacuum exhaust section 11.

[0059] During this process, film deposition is performed on the wafer W in the first and second film deposition steps. Furthermore, since the gas replacement in the processing vessel 10 is largely completed during the purging step by the constant exhaust of the automatic pressure control mechanism 2, unwanted by-products are generally not generated in the processing vessel 10. On the other hand, in the exhaust passage 16 of the automatic pressure control mechanism 2, gas replacement may not be completed upstream of the APC valve 3 and the shut valve 14, and there is a risk that by-products may be generated in the exhaust passage 16. However, as described above, the valve body 30 is provided with an annular upstream tapered surface 36 and a downstream tapered surface 35. The action of these upstream tapered surface 36 and downstream tapered surface 35 improves and homogenizes the conductance at the entire circumference of the valve body 30, especially at the upstream end 37 and the downstream end 38, reducing the residue of source gas and reaction gas and suppressing the generation of by-products.

[0060] Furthermore, by actively growing by-products on the upstream tapered surface 36 of the valve body 30, the residual gas in the exhaust flow can be reduced, thereby suppressing the generation of by-products downstream of the upstream tapered surface 36. Moreover, since by-products are grown upstream along the upstream tapered surface 36 of the valve body 30, even if by-products are grown on the upstream tapered surface 36, it is less likely to hinder the rotational operation of the valve body 30. As described above, the APC valve 3 in this disclosure can reduce residual gas in the exhaust passage 16 of the highly efficient film deposition apparatus 1 and suppress the generation of by-products that hinder the rotational operation of the valve body 30.

[0061] The APC valve 3 of this disclosure is a leak-type valve, but is not limited to this. Even in a sealed valve with zero gap width when fully closed, the conductance can be improved and made uniform if an upstream tapered surface 36 and a downstream tapered surface 35 are formed. Furthermore, the valve body 30 of this disclosure has an upstream tapered surface 36 and a downstream tapered surface 35 formed around the entire circumference of the valve body 30, but is not limited to this. For example, the upstream tapered surface 36 may be provided only at the downstream end 38, or the upstream tapered surface 36 may be formed in localized areas on the downstream end 38 side and the upstream end 37 side, respectively. In other words, the annularly formed upstream tapered surface 36 corresponds to the annular tapered surface on the surface 31 side in the claims, and includes surfaces corresponding to a first tapered surface provided on the downstream end 38 and a third tapered surface provided on the upstream end 37.

[0062] Furthermore, the downstream tapered surface 35 may be provided only at the upstream end 37, or the downstream tapered surface 35 may be formed in localized areas on the upstream end 37 side and the downstream end 38 side, respectively. In other words, the annularly formed downstream tapered surface 35 corresponds to the annular tapered surface on the back surface 32 side in the claims and includes a surface corresponding to the second tapered surface provided on the upstream end 37.

[0063] Figure 6 shows the valve body 30a according to the modified example in an inclined position. In Figure 6, the valve body 30a in the fully closed position is shown by a dashed line. In the valve body 30a, the upstream tapered surface 36a is formed only in the region on the downstream end 38a side, and the downstream tapered surface 35a is formed only in the region on the upstream end 37a side. In this case, when the valve body 30a is inclined position, the conductance of the upstream end 37a and the downstream end 38a, which have high conductances around the entire circumference of the valve body 30a, can be further improved and made uniform. Therefore, even with the modified valve body 30a, stagnation of the exhaust flow upstream of the valve body 30a can be reduced to reduce residual gas, the generation of by-products can be suppressed, and by-products can be grown on the upstream tapered surface 36a of the downstream end 38a to remove residual gas.

[0064] Furthermore, although the film deposition apparatus 1 and automatic pressure control mechanism 2 according to this disclosure have been described using the ALD method, which deposits films layer by layer, as an example, their effects are not limited to the ALD method. The film deposition apparatus 1 and automatic pressure control mechanism 2 according to this disclosure can also be used for other film deposition processes, such as the CVD (Chemical Vapor Deposition) method, which deposits films continuously, to promote gas replacement in the exhaust pipe 15 and control pressure while suppressing the effects of by-product adhesion. In addition, the film deposition apparatus 1 and automatic pressure control mechanism 2 according to this disclosure will have similar effects even when performing a film deposition process using the pyrolysis CVD method, which deposits films using only the source gas without using a reaction gas. In such a film deposition apparatus 1 and automatic pressure control mechanism 2, due to the thermal decomposition and reactions of the molecules constituting the various gases, for example, film-depositing molecules may unintentionally accumulate in the exhaust pipe 15, and molecules containing at least some of the atoms constituting the molecules of the various gases may unintentionally react in the exhaust pipe 15 to become by-products. Products formed by film-forming molecules within the exhaust pipe 15, as well as by-products resulting from the reaction of molecules containing at least some of the atoms that make up various gas molecules, are unintended products and are therefore collectively referred to as by-products.

[0065] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The above embodiments may be omitted, substituted, modified or combined in various ways without departing from the scope and spirit of the appended claims. [Examples]

[0066] (Preliminary experiment) An evaluation test was conducted to verify the effectiveness of the automatic pressure control device in the film deposition process according to this disclosure. First, the gap width between the valve body 30 and the valve seat 20 when fully closed, which have an upstream tapered surface 36 and a downstream tapered surface 35 with a taper angle of 45 degrees, was set to the above range, and the pressure was controlled within the above range of pressure values. In order to perform the film deposition process with the above settings, a gas supply mechanism 40 that alternately supplies source gas and reaction gas at a flow rate of 10 L per minute at atmospheric pressure at a temperature of 0°C was connected to a processing vessel 10 with a capacity of 30 L. In addition, an automatic pressure control mechanism 2 having a vacuum exhaust section 11 that performs vacuum exhaust at a rate of 30 KL per minute was connected to the processing vessel 10.

[0067] As shown in Figure 7, the change in pressure inside the processing container was investigated by varying the tilt angle for three samples with gap widths when fully closed: Sample 1 with a gap width of 0.1 mm, Sample 2 with a gap width of 0.3 mm, and Sample 3 with a gap width of 0.5 mm. In Figure 7, the dashed line shows the pressure change for Sample 1 with a gap width of 0.1 mm when fully closed, the dashed line shows the pressure change for Sample 2 with a gap width of 0.3 mm when fully closed, and the solid line shows the pressure change for Sample 3 with a gap width of 0.5 mm when fully closed.

[0068] According to these results, in all cases, the pressure in the processing container 10 could be controlled from 133 Pa (1 torr) to 400 Pa (3 torr) within the range of 10 to 30 degrees of the inclination angle of the valve body 30. Specifically, since the pressure in the processing container 10 can be controlled within the above-mentioned pressure range over a wide range of more than half of the inclination angle range of 10 to 30 degrees, it is easy to adjust the pressure control in this range by adjusting the inclination angle of the valve body 30. On the other hand, if the gap width when fully closed is made smaller than 0.1 mm, for example, it becomes necessary to control the pressure in a relatively narrow range on the upper end of the inclination angle range of the valve body 30. Also, if the gap width when fully closed is made larger than 0.5 mm, for example, it becomes necessary to control the pressure in a relatively narrow range on the lower end of the inclination angle range of the valve body 30. For this reason, it is preferable to set the gap width when fully closed within the above-mentioned range.

[0069] (Examples) Figures 8A and 8B are explanatory diagrams showing images obtained during an evaluation test of the automatic pressure control mechanism 2 using a valve body 30 manufactured in accordance with the embodiment of this disclosure. Figure 8A is an image of the downstream end 38 of the valve body 30 taken from the front side, and Figure 8B is an observation of the upstream end 37 of the valve body 30 taken from the back side. Figures 8A and 8B show the state in which the automatic pressure control mechanism 2 using the valve body 30 of Figure 4 described above is operated and 17,000 wafers W have been deposited.

[0070] The by-products of the upstream tapered surface 36 of the valve body 30 are multiple linear by-products S that are generated on the upstream tapered surface 36 from the downstream side toward the upstream side, and these are densely generated over the circumferential direction of the upstream tapered surface 36 at the ends excluding the side of the rotation axis L. Furthermore, these multiple linear by-products of the upstream tapered surface 36 overlap and thicken on the upstream tapered surface 36 side of the surface 31. The by-products that grow in this way do not easily extend outward from the rotational trajectory of the side surface 33 of the valve body 30 during tilting operation, and do not easily hinder the rotation of the valve body 30 during tilting operation.

[0071] Furthermore, the linear by-product S extended relatively long at both the upstream end 37 and the downstream end 38, with a relatively larger quantity produced at the downstream end 38 than at the upstream end 37. No by-product adhesion was observed on the side surface 33 and the downstream tapered surface 35. While the by-product adhesion on surfaces 31 other than the upstream tapered surface 36 was more noticeable than that on the back surface 32 other than the downstream tapered surface 35, overall the adhesion of by-products was suppressed. No significant by-product adhesion was observed on the inner wall surface 21 of the valve seat 20. Although not shown in the illustration, no significant by-product adhesion was observed on the shut valve 14. From the above, it can be concluded that, under the above conditions, the APC valve 3 suppressed adhesion to the entire exhaust passage 16 and effectively recovered by-products with the valve body 30 without causing any problems with the tilting operation of the APC valve 3.

[0072] (Comparative example) Figures 9A to 9C are explanatory diagrams showing images obtained during an evaluation test of the automatic pressure control mechanism 2 using a valve body 30A manufactured in accordance with the first comparative configuration. Figure 9A is an image of the upstream end 37 of the valve body 30A taken from the front surface 31A side, Figure 9B is an image of the downstream end 38 of the valve body 30A taken from the back surface 32A side, and Figure 9C is an image of the shut valve 14 taken from the back surface, which is the downstream side. Figures 9A to 9C show the state in which the automatic pressure control mechanism 2 using the valve body 30A of the first comparative configuration described in Figure 3A is operated and 20,000 wafers W have been deposited.

[0073] As shown in Figure 9A, partially enlarged by-product S1 is attached to the upstream end 37 of the valve body 30 and to the portion of the inner wall surface 21 of the valve seat 20 near the upstream end 37. As shown in Figure 9B, a small amount of by-product S2 is densely formed in the gap between the downstream end 38 of the valve body 30 and the inner wall surface 21 of the valve seat 20, extending along the periphery of the downstream tapered surface of the valve body 30. The by-products thus formed are arranged in a manner that obstructs the rotational trajectory of both ends 34 during tilting operation. Furthermore, in the comparative example APC valve 3, by-products were irregularly attached to the upstream end 37 of the valve body 30. Therefore, with the comparative example valve body 30A, the timing of maintenance is unpredictable, and maintenance needs to be performed earlier.

[0074] As shown in Figures 9A to 9C, by-products were widely visible throughout the valve body 30A, the inner wall surface 21 of the valve seat 20, and the entire area of ​​the downstream shut valve 14. This is thought to be because the exhaust flow stagnated upstream of the valve body 30A, increasing the amount of residual gas, and thus generating by-products throughout the entire area in contact with the exhaust flow. Furthermore, in the case of the comparative example valve body 30A, since it lacks the upstream tapered surface 36 with a predetermined taper angle like the valve body 30 of this disclosure, the recovery of by-products was insufficient, and it is thought that a large amount of by-product S3 adhered to the downstream shut valve. [Explanation of symbols]

[0075] W wafer 2. Automatic pressure control mechanism 3 APC valves 7 shafts 10 Processing containers 11 Vacuum exhaust section 16 Exhaust passage 20 valve seats 21 Interior wall surface 22 Intermediate exhaust passage 30 valve body 30a Valve body 31 Surface 32 Back side 35 Downstream tapered surface 35a Downstream tapered surface 36 Upstream tapered surface 36a Upstream tapered surface 37 Upstream end 37a Upstream end 38 Downstream end 38a Downstream end

Claims

1. An automatic pressure control device that controls the pressure inside a processing vessel to which a source gas for forming a film on a substrate is supplied, A vacuum exhaust unit for evacuating the gas inside the processing container, An exhaust passage connecting the processing container and the vacuum exhaust section, A butterfly valve having an annular valve seat whose inner wall surface forms part of the exhaust passage, and a valve body configured as a plate-like body for blocking at least part of the cross-section that crosses the annular valve seat, and rotatably mounted to the valve seat via a shaft, and changing the opening area of ​​the exhaust passage by changing the angle of inclination of the valve body with respect to the cross-section via the shaft, wherein the pressure inside the processing container is controlled by changing the angle of inclination of the valve body based on the detection result of the pressure inside the processing container, Equipped with, When viewed from the upstream side in the flow direction of the gas in the exhaust passage, the upstream surface of the valve body is called the front surface and the downstream surface is called the back surface, a first tapered surface is formed on the front surface of the valve body in the region located at the downstream end in the flow direction when the valve body is inclined, and a second tapered surface is formed on the back surface of the valve body in the region located at the upstream end in the flow direction when the valve body is inclined. The valve body, when in the inclined arrangement, is used within the range of an inclination angle of 10 to 30 degrees, and the angle between the region of the surface excluding the first tapered surface and the first tapered surface, and the angle between the region of the back surface excluding the second tapered surface and the second tapered surface, are each greater than 95 degrees and 150 degrees or less. The butterfly valve is configured as a leak-type butterfly valve in which a gap is formed between the inner circumference of the valve seat and the outer circumference of the valve body when the inclination angle is 0 degrees and the valve is fully closed. An automatic pressure control device in which the width of the gap is 0.1 mm or more and less than 1 mm.

2. The automatic pressure control device according to claim 1, wherein a third tapered surface is formed on the surface of the valve body in a region located at the upstream end in the flow direction when the valve body is inclined, and by-products generated due to the source gas remaining in the exhaust passage are grown on the first and third tapered surfaces.

3. The automatic pressure control device according to claim 2, wherein an annular tapered surface is formed on the surface of the valve body in an annular shape along the periphery of the valve body, and the first tapered surface and the third tapered surface are included in the annular tapered surface on the surface side.

4. The automatic pressure control device according to claim 1, wherein an annular tapered surface is formed on the back surface of the valve body in an annular shape along the peripheral edge of the valve body, and the second tapered surface is included in the annular tapered surface on the back surface side.

5. The automatic pressure control device according to any one of claims 1 to 4, The processing container for housing the substrate on which the film is to be formed, A gas supply mechanism that supplies the source gas to the processing container, A film deposition apparatus equipped with the following features.

6. A method for controlling the pressure inside a processing vessel included in a film deposition apparatus to which a source gas is supplied, The gas supply mechanism of the film deposition apparatus includes the step of supplying the source gas into the processing container, A butterfly valve having an annular valve seat whose inner wall surface forms part of an exhaust passage, and a valve body configured as a plate for blocking at least a portion of the cross-section that crosses the annular valve seat, and rotatably mounted to the valve seat via a shaft, and changing the opening area of ​​the exhaust passage by changing the angle of inclination of the valve body with respect to the cross-section via the shaft, wherein the pressure inside the processing container is controlled by changing the angle of inclination of the valve body based on the detection result of the pressure inside the processing container, wherein, when viewed from the upstream side in the flow direction of the gas in the exhaust passage, the upstream surface of the valve body is called the front surface and the downstream surface is called the back surface, a first tapered surface formed in a region located at the downstream end in the flow direction of the front surface of the valve body, which is arranged at an inclination angle of 10 to 30 degrees, and a second tapered surface formed in a region located at the upstream end in the flow direction of the back surface, are used to equalize the width of the gap with the inner circumference of the valve seat and control the pressure inside the processing container while exhausting the gas inside the processing container; A step of growing by-products generated due to the source gas remaining in the exhaust passage onto the first tapered surface, Includes, The angle between the surface and the first tapered surface, and the angle between the back surface and the second tapered surface, are each greater than 95 degrees and less than or equal to 150 degrees. The butterfly valve is configured as a leak-type butterfly valve in which a gap is formed between the inner circumference of the valve seat and the outer circumference of the valve body when the inclination angle is 0 degrees and the valve is fully closed. A pressure control method wherein the width of the gap is 0.1 mm or more and less than 1 mm.

Images