JP2016180495A - Vacuum valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum valve which enables a by-product to be easily sublimed when the valve is opened, maintains seal performance for a long time, and enables easy maintenance of an elastic seal member.SOLUTION: A vacuum valve 1A includes: a body 4 in which a first port formation member 13 and a second port formation member 14 are integrally provided with a valve body member 12; a valve body 3 incorporated into the valve body member 14; a valve seat part 5 with/from which the valve body 3 contacts/separates; an elastic seal member 7 which is pushed and crushed to be elastically deformed between the valve body 3 and the valve seat 5; driving means 2 which applies a driving force to the valve body 3; and a heater 10 which heats the body 4. The elastic seal member 7 is attached to the valve seat part 5. The vacuum valve 1A has holding means 6 detachably attached to an inner wall of the body 4 and configured to hold the elastic seal member 7.SELECTED DRAWING: Figure 1

Description

  In the present invention, the first port portion and the second port portion protrude integrally with the valve body portion, the body through which the reaction gas flows, the valve seat provided in the body, and the valve seat abuts or separates. A valve body; an elastic seal member that is crushed and elastically deformed between the valve body and the valve seat; a driving unit that is connected to the body and applies a driving force to the valve body; and the body is heated. The present invention relates to a vacuum valve including a heater.

  For example, in a semiconductor manufacturing apparatus, a vacuum valve is disposed between a reaction chamber and a vacuum pump. The vacuum valve is used to control the exhaust flow rate when the reaction gas used for film formation of the semiconductor is exhausted from the reaction chamber to the vacuum pump, or to control the vacuum pressure in the reaction chamber to be constant.

  FIG. 26 is a cross-sectional view of the vacuum valve 101 of the first conventional example. In the vacuum valve 101, the driving means 110 is connected to a body 120 in which a first port portion 121 and a second port portion 122 project integrally with a valve body portion 123. The valve body 112 is connected to the drive shaft 111 of the drive means 110, and abuts on or separates from the valve seat surface 124 provided on the body 120 by the drive force of the drive means 110. The valve body 112 is sealed by attaching an elastic seal member 115 to a seal surface 112 a facing the valve seat surface 124, and bringing the elastic seal member 115 into close contact with the valve seat surface 124. The vacuum valve 101 is provided with heaters 114 and 141 on the drive shaft 111 and the body 120 in order to prevent the generation of by-products (substances generated by a reaction different from the intended reaction in the chemical reaction) in the flow path. , 142, and 143 (see, for example, Patent Document 1).

  FIG. 27 is a cross-sectional view of a main part of the vacuum valve 201 of the second conventional example. The vacuum valve 201 is closed by bringing an elastic seal member 212 provided on the valve body 210 into close contact with a valve seat surface 221 provided on the body 220. The body 220 has an annular wall 231 formed thereon. The annular wall 231 is provided inside the valve seat surface 221 and the elastic seal member 212. The valve body 210 is formed with an annular groove 211 that fits with the annular wall 231 to form a minute throttle channel 241 when the valve opening operation of the vacuum valve 201 is started. In such a vacuum valve 201, at the start of the valve opening operation, the reaction gas is reduced in flow rate in the throttle channel 241, and then passes between the elastic seal member 212 and the valve seat surface 221, so that the reaction gas is generated as a by-product. Objects easily adhere to the surface of the annular wall 231 and the inner wall of the annular groove 211, and adhesion to the elastic seal member 212 and the valve seat surface 221 is reduced (see, for example, Patent Document 2).

  FIG. 28 is a cross-sectional view of a vacuum valve unit 301 of the third conventional example. The vacuum valve unit 301 has a rough exhaust valve body 362 and a main exhaust valve body 330 in a single structure. The body 310 is fixed by the port forming member 315 being inserted through the fixing screw 316 in the direction opposite to the valve closing direction of the main exhaust valve body 330 and fastening the fixing screw 316 to the cylinder body 314. The port forming member 315 is provided with a main exhaust valve seat 317, and an elastic seal member 318 is fitted in an annular groove provided in the main exhaust valve seat 317. When the rough exhaust knob 361 is rotated from the state shown in FIG. 28, the vacuum valve unit 301 lowers the rough exhaust valve body 362, opens the rough exhaust valve seat 363, and performs pressure reduction to a low vacuum pressure. In the vacuum valve unit 301, after rough exhaust, the rough exhaust knob 361 is rotated in the reverse direction, and when the vacuum valve unit 301 is returned to the state shown in FIG. 28, the main exhaust knob 364 is rotated. As a result, the main exhaust valve body 330 rises to open the main exhaust valve seat 317 and perform pressure reduction to a high vacuum pressure (see, for example, Patent Document 3).

JP 2001-173838 A JP 2008-69943 A Japanese Patent No. 4888949

However, the vacuum valves 101, 201, and 301 of the first to third conventional examples have the following problems.
In the vacuum valve 101 of the first conventional example, by-products were attached to the elastic seal member 115 even though the heaters 114, 141, 142, and 143 heated the valve body 112 and the body 120.

  FIGS. 29A and 29B are views showing the seal portion 115a of the elastic seal member 115 after using the vacuum valve 101 of the first conventional example. FIG. 29A is a plan view of the elastic seal member 115, and FIG. It is XX sectional drawing of (A). Note that the by-product Y described in FIGS. 29A and 29B is described with emphasis on the film thickness, size, and the like in order to make the drawing easy to see. The inventors removed the elastic seal member 115 from the vacuum valve 101 after use, and confirmed the seal portion 115a with a micrograph. As shown in FIGS. 29 (A) and 29 (B), the inner portion of the seal portion 115a. A large amount of by-product Y was deposited on the inner side P1 of the elastic seal member 115 and the outer side P2 of the seal portion 115a (the outer peripheral side of the elastic seal member 115). The amount of the by-product Y decreased from the portions P1 and P2 to the outer peripheral side of the elastic seal member 115.

  Regarding the cause of the adhesion of the by-product Y, the inventors have confirmed that when the valve body 112 is lifted so as to separate the elastic seal member 115 from the valve seat surface 124, the elastic seal member 115 is attached to the heaters 141, 142, and 143. This was thought to be because the heat of the heater was not transmitted and the surface temperature was lowered. In addition, when the valve body 112 is lifted so that the elastic seal member 115 is separated from the valve seat surface 124, the inventors flow the reaction gas to the elastic seal member 115, cool the gas, and lower the temperature. It was thought that by-products were deposited on the surface of the elastic seal member 115.

  In addition, as shown in FIG. 29B, the inventors have confirmed that the by-product Y is stuck to the inner portion P1 and the outer portion P2 from the seal portion 115a of the elastic seal member 115 in a film shape. did. The inventors considered the cause as follows. Since the elastic seal member 115 transmits the heater heat of the heaters 141, 142, and 143 via the valve seat surface 124 when the valve is closed, the by-product Y attached to the surface of the elastic seal member 115 is sublimated when the valve is closed. try to. However, in the vicinity of the seal portion 115a of the elastic seal member 115, the by-product Y is sandwiched between the elastic seal member 115 and the valve seat surface 124 and cannot move freely. When the vacuum valve 101 is opened next, the elastic seal member 115 cannot transmit the heater heat, and the remaining by-product Y is exposed to the reaction gas, so that it remains in the vicinity of the seal portion 115a of the elastic seal member 115. A new by-product Y will be deposited on the by-product Y. Thereafter, when the vacuum valve 101 is closed again, the new by-product Y is pressed onto the old by-product Y, and they are mixed by the heater heat and spread in a film shape. By repeating this, it is considered that the by-product Y sticks in the form of a film near the seal portion 115a.

  The by-product Y does not adhere to the elastic seal member 115 with a uniform thickness along the circumferential direction of the seal portion 115a. Therefore, if the vacuum valve 101 continues to be used, the by-product Y adhering to the elastic seal member 115 cannot uniformly seal the seal portion 115a to the valve seat surface 124 in the circumferential direction. May decrease. In order to avoid this problem, it is necessary to perform maintenance of the elastic seal member 115 and the like in a short cycle. At the time of this maintenance, it is necessary to stop the semiconductor production line, so that the semiconductor production efficiency is lowered. Therefore, in order to reduce the maintenance frequency, a vacuum valve capable of maintaining the sealing performance for a long time has been demanded from the field.

  Here, as shown in the graph of FIG. 30, the amount of sublimation of the reactive gas increases as the heating temperature increases. Therefore, it can be considered that if the amount of heat generated by the heater 114 is increased, the by-product Y can be sublimated by heating the elastic seal member 115 to a high temperature even when the valve is open. However, this method is not preferable because the driving unit 110 may be damaged by heat.

  On the other hand, as shown in the graph of FIG. 30, even when the reaction gas has the same heating temperature, the sublimation amount can be increased if the pressure of the reaction gas is low. Therefore, if the inventors can derive a structure that heats the elastic seal member 115 even when the valve is opened and reduces the pressure of the reaction gas flowing in the vicinity of the elastic seal member 115, the by-product Y sublimates when the valve is opened. This led to the idea that the sealing performance can be maintained for a long time.

  In the vacuum valve 201 of the second conventional example, when the valve body 210 is lifted so that the annular wall 231 and the annular groove 211 are not fitted together, the reaction gas is eliminated from the throttle flow path 241, thereby suppressing the adhesion of by-products. No effect. In this case, since the elastic seal member 212 is attached to the valve body 210 in the vacuum valve 201 of the second conventional example, the by-product attached to the elastic seal member 212 is the same as the vacuum valve 101 of the first conventional example. There is a possibility that the sealing performance is deteriorated without sublimation.

  In the vacuum valve unit 301 of the third conventional example, the elastic seal member 318 is attached to the main exhaust valve seat 317. Therefore, if the body 310 is heated with a heater, the elastic seal member 318 can be heated even when the valve is opened. It is done. However, in the vacuum valve unit 301, when the main exhaust valve body 330 rises and opens, the elastic seal member 318 is exposed to the reaction gas, and the flow velocity and pressure near the elastic seal member 318 increase. Therefore, even if the body 310 is heated with a heater, the elastic seal member 318 is deprived of heat by the reaction gas, and the byproduct cannot be sublimated efficiently.

  The vacuum valve unit 301 performs rough exhaust and main exhaust with separate valve bodies 362 and 330, and the vacuum valves of the first and second conventional examples in which flow control is performed with one valve body 112 and 210. 101 and 201 are different in structure. Such a vacuum valve unit 301 has a smaller differential pressure between the upstream side and the downstream side across the main exhaust valve body 330 when the main exhaust valve body 330 is opened, compared to the vacuum valves 101 and 201. The seal load acting on the exhaust valve body 330 is smaller than the seal load acting on the valve bodies 112 and 210 of the vacuum valves 101 and 201. Therefore, in the vacuum valve unit 301, the valve forming member 315 fixed to the cylinder body 314 with the fixing screw 316 can be provided with the valve seat 317 and the elastic seal member 318, but the vacuum valve 101, 201 has the vacuum valve unit 301. It was difficult to apply the valve structure. This is because in this case, the fixing screw has insufficient strength against the seal load. Further, for example, as with the vacuum valve unit 301, even if a configuration in which a mounting groove is formed in the valve seat surface 124 of the vacuum valve 101 and an elastic seal member is mounted is used, the vacuum valve 101 has the first port. Since the part 121 and the second port part 122 are integrally projected on the valve body part 123, it takes time to mount the elastic seal member. In particular, when the reaction gas enters between the mounting groove and the elastic seal member and is solidified, it is very difficult to remove the elastic seal member.

  The present invention has been made to solve the above-mentioned problems, and is a vacuum valve in which by-products are easily sublimated when the valve is opened, the sealing performance can be maintained for a long time, and the elastic seal member is easily maintained. The purpose is to provide.

One embodiment of the present invention has the following configuration.
(1) The first port portion and the second port portion are integrally projected on the valve main body portion, the body through which the reaction gas flows, the valve seat provided on the body, and the valve that contacts or separates from the valve seat A body, an elastic seal member that is crushed and elastically deformed between the valve body and the valve seat, a driving means that is connected to the body and applies a driving force to the valve body, and a heater that heats the body The elastic seal member is mounted on the valve seat, and is detachably attached to the inner wall of the body, and has holding means for holding the elastic seal member. .

  In the above configuration, the first port portion of the body projects integrally with the valve body portion, and the strength against the sealing load provided on the body is ensured. Since the elastic seal member is provided in the valve seat provided in the body, when the heater heats the body, the heater heat is any valve opening between the valve closed state and the fully open state, It is transmitted to the elastic seal member through the body and the valve seat. In addition, for example, when the reaction gas is supplied to the first port, the reaction gas flows toward the valve body, so that the elastic seal member provided on the valve seat is not easily exposed to the reaction gas. Therefore, when the valve is opened, the pressure near the elastic seal member becomes lower than the pressure near the valve body. As shown in FIG. 30, even in the case of the same heating temperature, the sublimation amount increases as the pressure decreases. Therefore, the by-product is easily sublimated when the valve is opened, and hardly adheres to the seal portion of the elastic seal member. In addition, since the by-product can be sublimated when the valve is opened, even if the valve opening / closing operation is repeated, the by-product remains on the seal portion of the elastic seal member and is not compressed. Therefore, according to the said structure, it can suppress that a by-product adheres to the seal part of an elastic seal member at the time of valve opening, and can maintain sealing performance for a long period of time.

  In the above configuration, the valve seat is provided in a body in which the first and second port portions are provided integrally with the valve main body portion, and an elastic seal member is mounted on the valve seat. If the means is removed from the body together with the valve body, and the holding means is attached to and detached from the body, it can be easily attached to and detached from the valve seat. Therefore, according to the said structure, an elastic seal member can be maintained easily.

(2) In the configuration described in (1), the valve seat has a dovetail groove in which the elastic seal member is mounted, and the valve body has an outer diameter dimension of a seal surface that is in close contact with the elastic seal member. It is preferable that it is below the outer diameter dimension of the bottom part of the said dovetail.

  According to the said structure, if it is the same seal diameter, the outer diameter dimension of a valve body can be made smaller than a valve body provided with the dovetail groove | channel which mounts an elastic seal member. Therefore, in the above configuration, the reaction gas that has passed through the elastic seal member flows out immediately into the valve body, and the pressure near the elastic seal member can be reduced. Therefore, according to the said structure, the by-product adhering to the elastic seal member at the time of valve opening tends to sublime.

(3) In the configuration described in (2), the valve seat has a bulging portion projecting radially inwardly on an inner peripheral surface of an opening portion that opens to the valve body side, and the dovetail groove is the bulging portion. It is preferable that the valve seat is formed so as to project to the protruding portion side.

  According to the above configuration, since the radial thickness of the opening of the valve seat is increased by the bulging portion, the elastic seal member has the same seal diameter as that when the elastic seal member is attached to the valve body. Dovetail grooves can be formed. Therefore, according to the said structure, a valve body can be made compact.

(4) In the configuration described in any one of (1) to (3), it is preferable to have a throttle portion provided inside the elastic seal member.

  In the above configuration, even when the valve opening is small and the pressure in the vicinity of the elastic seal member is high, the reaction gas is reduced in flow rate by the throttle portion to reduce the pressure, and then the elastic seal member and the valve body Since it passes through, the by-product adhering to the elastic seal member is easily sublimated.

  Therefore, according to the said structure, a by-product can be easily sublimated at the time of valve opening, a sealing performance can be maintained for a long period of time, and a vacuum valve with easy maintenance of an elastic seal member can be provided.

It is sectional drawing of the vacuum valve which concerns on 1st Embodiment of this invention, Comprising: A valve closed state is shown. It is sectional drawing of the vacuum valve shown in FIG. 1, Comprising: A valve open state is shown. It is a figure which shows the valve structure of the vacuum valve shown in FIG. It is sectional drawing which shows the valve structure of a comparative example. The result of analyzing the flow velocity distribution when the comparative example is fully opened is shown. The result of having analyzed the pressure distribution at the time of fully opening a comparative example is shown. The result of having analyzed flow velocity distribution at the time of fully opening Example 1 is shown. The result of having analyzed the pressure distribution at the time of fully opening Example 1 is shown. The comparative example shows the result of analyzing the flow velocity distribution when the valve is opened at an opening degree of 60% with respect to full opening. The comparative example shows the result of analyzing the pressure distribution when the valve is opened at an opening degree of 60% with respect to full opening. The result of having analyzed the flow-velocity distribution at the time of Example 1 opening a valve by 60% of opening degree with respect to the time of a full open is shown. The result of having analyzed the pressure distribution at the time of opening Example 1 by 60% of opening degree with respect to full open is shown. It is sectional drawing which shows the valve structure of Example 2. FIG. The result of having analyzed the flow-velocity distribution at the time of Example 2 opening a valve with the opening degree of 2% with respect to the opening degree at the time of a full open is shown. The result of having analyzed the pressure distribution at the time of opening Example 2 by 2% of opening degree with respect to the opening degree at the time of full opening is shown. The result of having analyzed the flow-velocity distribution at the time of Example 1 opening a valve with the opening degree of 2% with respect to the opening degree at the time of a full open is shown. The result of having analyzed Example 1 the pressure distribution at the time of valve opening by 2% of opening degree with respect to the opening degree at the time of a full open is shown. It is sectional drawing which shows the valve structure of Example 3 corresponding to the vacuum valve which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the valve structure of Example 4 corresponding to the vacuum valve which concerns on 2nd Embodiment of this invention. The result of having analyzed the flow-velocity distribution at the time of setting the opening degree of Example 3 to 2% is shown. The result of having analyzed the pressure distribution at the time of setting the opening degree of Example 3 to 2% is shown. The result of having analyzed the flow-velocity distribution at the time of making Example 4 into 2% of opening degree is shown. The result of having analyzed the pressure distribution at the time of opening Example 2 for 2% is shown. It is sectional drawing which shows the valve structure of the vacuum valve which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the valve structure of the vacuum valve which concerns on 4th Embodiment of this invention. It is sectional drawing of the vacuum valve of a 1st prior art example. It is principal part sectional drawing of the vacuum valve of a 2nd prior art example. It is sectional drawing of the vacuum valve of a 3rd prior art example. It is a figure which shows the seal part of the elastic seal member after using the vacuum valve of a 1st prior art example, Comprising: (A) shows the top view of an elastic seal member, (B) is XX sectional drawing of (A). is there. It is a graph which shows the sublimation of a reactive gas, Comprising: Temperature (degreeC) is shown on a horizontal axis | shaft and pressure (Pa) is shown on a vertical axis | shaft.

  Hereinafter, embodiments of a vacuum valve according to the present invention will be described with reference to the drawings.

(First embodiment)
(Overall configuration of vacuum valve)
FIG. 1 is a cross-sectional view of a vacuum valve 1A according to a first embodiment of the present invention, showing a valve closed state. FIG. 2 is a cross-sectional view of the vacuum valve 1A shown in FIG. 1 and shows a valve open state.
The vacuum valve 1 </ b> A has an external appearance in which the driving means 2 is fixed to the body 4 with a bolt (not shown). The vacuum valve 1 </ b> A performs fluid control by causing the valve body 3 provided in the body 4 to reciprocate linearly along the axis by the driving means 2 to abut or separate from the valve seat portion 5.

  The body 4 is formed of a metal having excellent corrosion resistance, heat resistance, and heat transfer properties such as stainless steel. In the body 4, the first port forming member 13 (an example of the first port portion) is butt welded to the lower end opening of the valve body member 12, and the second port forming member 14 (an example of the second port portion) is The side surface of the main body member 12 is butt welded to a flange portion 12b provided in a direction orthogonal to the axis. Therefore, in the body 4, the first port 13a provided in the first port forming member 13 communicates coaxially with the valve chamber 12a, and the second port 14a provided in the second port forming member 14 has the valve chamber. It communicates in a direction orthogonal to 12a, and the flow path 8 is formed in an L shape.

  The valve seat portion 5 is provided coaxially between the first port 13a and the valve chamber 12a. An elastic seal member 7 in which a heat-resistant rubber is formed in an annular shape is attached to the valve seat portion 5 so as to be elastically deformable, and the valve body 3 is in close contact with the elastic seal member 7. The configuration of the valve seat portion 5 will be described later.

  The drive means 2 is connected to the body 4 with the drive shaft 2a protruding into the valve chamber 12a. The drive shaft 2a is disposed coaxially with the valve chamber 12a, and the valve body 3 is connected to the lower end portion. In the driving means 2, the compression spring 2 b always applies a biasing force in the direction of the valve seat 5 to the valve body 3. The drive means 2 controls the valve opening degree by causing the valve body 3 to reciprocate linearly along the axis. The bellows 9 is disposed in the valve chamber 12a so as to be extendable and contractible while covering the drive shaft 2a and the compression spring 2b. The bellows 9 has an upper end 9a sandwiched between the driving means 2 and the body 4, while a lower end 9b is fixed to the valve body 3 by welding or the like. Is prevented from leaking to the driving means 2 side. The valve body 3 and the bellows 9 are made of a metal such as stainless steel having excellent corrosion resistance, heat resistance, and heat transfer.

  The vacuum valve 1 </ b> A is heated by the heaters 10 and 11 in order to prevent by-products from being generated in the flow path 8. The heater 10 is mounted on the body 4 and heats the body 4, the valve seat portion 5, and the elastic seal member 7. The heater 11 is installed in the lower end part of the drive shaft 2a, and heats the valve body 3 and the bellows 9. FIG. In order to prevent the driving unit 2 from being heated excessively, the heater 11 is set to have a small amount of heat generated from the heater 10.

(About the structure of the valve seat)
FIG. 3 is a view showing a valve structure of the vacuum valve 1A shown in FIG.
In the valve seat portion 5, the holding means 6 is attached to the valve seat forming portion 13c provided in the first port forming member 13, whereby the elastic seal member 7 is mounted on the valve seat surface 5a so as to be elastically deformable. In order to ensure conductance, the valve seat portion 5 is provided with a valve seat surface 5a at the same position as the bottom portion 14b of the second port 14a.

  The first port forming member 13 has a first port 13a having a smaller diameter than the valve chamber 12a, and an end wall located on the valve body 3 side has an annular closing wall 13h for closing the opening of the valve body member 12 Is provided. The annular wall 13b is suspended from the valve body 3 side (drive means 2 side) along the outer edge of the closing wall 13h, and is welded to the lower end of the valve body member 12 in the figure.

  The closing wall 13h is provided at a position inside the annular wall 13b so that a cylindrical valve seat forming portion 13c protrudes toward the valve body 3 side. The valve seat forming portion 13c has a flat end surface located on the valve body 3 side, and is provided at the same position as the bottom portion 14b of the second port 14a. The valve seat forming portion 13c is provided so as to be coaxial with the first port 13a and the valve chamber 12a. The bulging portion 13d is provided on the inner peripheral surface of the valve seat forming portion 13c so as to protrude radially inward, and the inner diameter dimension B of the opening portion that opens to the valve seat surface 5a is the inner diameter of the first port 13a. It is made smaller than the dimension A.

  The valve seat forming portion 13c is provided with a stepped portion 13g that is recessed on the side opposite to the valve body 3 on the end surface located on the valve body 3 side. The holding means 6 includes a ring plate-shaped ring member 6a placed on the stepped portion 13g, and a plurality of fixing screws 6b that are inserted into the ring member 6a and fastened to screw holes 13i provided in the valve seat forming portion 13c. Is provided. The ring member 6a is provided with the same thickness as the stepped portion 13g, and forms the valve seat surface 5a together with the valve seat forming portion 13c. A dovetail groove 15 is provided between the inner peripheral surface of the ring member 6a and the peripheral wall of the step portion 13g, and the elastic seal member 7 is mounted on the valve seat portion 5 in contact with the inner wall of the dovetail groove 15. . The fixing screw 6b is housed in a recess 6c formed in the ring member 6a so that the flow of the reaction gas is not hindered. The ring member 6a and the fixing screw 6b are formed of a metal excellent in corrosion resistance, heat resistance, and heat transfer, such as stainless steel. Therefore, the elastic seal member 7 receives the heater heat of the heater 10 via the ring member 6a and the valve seat forming portion 13c, and is heated to the same degree as the heater heat at any valve opening from the valve closed state to the fully open state. The

  Here, the valve seat formation part 13c has the bulging part 13d as mentioned above, and the thickness of the valve seat surface 5a vicinity is made thick in radial direction. Therefore, the valve seat portion 5 is provided on an extension line in which the dovetail groove 15 extends the inner wall 13f of the first port 13a to the driving means 2 side, for example, as in the first and second conventional examples shown in FIGS. The elastic seal member 7 can be mounted so as to have the same seal diameter as that when the elastic seal members 115 and 212 are mounted on the valve bodies 112 and 210. In other words, the valve body 3 of the present embodiment can be made more compact than the valve body to which the elastic seal member is mounted by making the outer diameter dimension C of the sealing surface 3a smaller than the bottom outer diameter dimension D of the dovetail groove 15a.

  In addition, the valve seat formation part 13c is provided with the taper surface 13e between the bulging part 13d and the inner wall 13f of the 1st port 13a, and can make a reaction gas flow smoothly.

(Explanation of vacuum valve operation)
In the vacuum valve 1A, for example, the first port 13a is connected to a reaction chamber of a semiconductor manufacturing apparatus, and the second port 14a is connected to a vacuum pump. When the vacuum valve 1A is not exhausted from the reaction chamber, the driving means 2 is not driven. In this case, the valve body 3 is pushed down by the spring force of the compression spring 2 b and is in close contact with the elastic seal member 7 for sealing. Thereby, 1 A of vacuum valves will be in a valve closed state.

  For example, when starting the exhaust of the reaction gas from the reaction chamber, the vacuum valve 1A exhausts the reaction gas at a minute flow rate because the differential pressure between the first port 13a and the second port 14a is large. For example, in the vacuum valve 1A, the driving means 2 slightly lifts the valve body 3 against the compression spring 2b to reduce the amount of elastic deformation of the elastic seal member 7, so that the elastic seal member 7 and the valve body 3 Let the reaction gas leak through. Accordingly, the reaction gas is exhausted from the reaction chamber at a minute flow rate so as not to wind up the particles, and the reaction chamber is decompressed.

  When the reaction chamber is depressurized to a predetermined low vacuum set pressure, the differential pressure between the first port 13a and the second port 14a is reduced in the vacuum valve 1A. Therefore, the vacuum valve 1A exhausts the reaction gas at a large flow rate. That is, in the vacuum valve 1A, the driving means 2 further raises the valve body 3 against the compression spring 2b and separates it from the elastic seal member 7, thereby increasing the valve opening. Thereby, the exhaust speed of the reaction gas is increased and the exhaust time is shortened.

  When the internal pressure of the reaction chamber is reduced to a predetermined high vacuum set pressure, the vacuum valve 1A stops the driving means 2. Then, the valve body 3 is lowered by being biased by the compression spring 2 b and is brought into close contact with the elastic seal member 7. Thereby, the vacuum valve 1A returns to the valve closed state. The vacuum valve 1A repeats the valve opening / closing operation each time the reaction gas is replaced in the reaction chamber, for example.

  By the way, the vacuum valve 1A is heated by the heaters 10 and 11 while the semiconductor manufacturing apparatus operates. In the vacuum valve 1A, since the elastic seal member 7 is provided in the valve seat portion 5, when the heater 10 heats the body 4, the heater heat has any valve opening degree from the valve closed state to the fully opened state. Is also transmitted to the elastic seal member 7 through the body 4 and the valve seat portion 5. In particular, since the valve seat portion 5 is composed of a ring member 6a made of a metal having good heat conductivity and a valve seat forming portion 13c, the elastic seal member 7 is easily heated. Moreover, when the reaction gas is supplied to the first port 13a, the reaction gas flows toward the seal surface 3a of the valve body 3, so that the elastic seal member 7 provided in the valve seat portion 5 is exposed to the reaction gas. Hateful. Therefore, when the valve is opened, the pressure near the elastic seal member 7 becomes lower than the pressure near the seal surface 3 a of the valve body 3. As shown in FIG. 30, even in the case of the same heating temperature, the sublimation amount increases as the pressure decreases. Therefore, the by-product is easily sublimated when the valve is opened, and hardly adheres to the seal portion of the elastic seal member 7. Further, since the by-product can be sublimated when the valve is opened, even if the valve opening / closing operation is repeated, the by-product remains on the seal portion of the elastic seal member 7 and is not compressed. Therefore, according to the vacuum valve 1 </ b> A, by-products are prevented from adhering to the seal portion of the elastic seal member 7 when the valve is opened, and the sealing performance can be maintained for a long time.

  The vacuum valve 1A has a large seal load so that the valve can be closed even in a high vacuum state. The seal load acts on the welded portion between the first port forming member 13 and the valve main body member 12 via the elastic seal member 7 and the valve seat forming portion 13c. Therefore, the vacuum valve 1A has sufficient strength of the body 4 against the seal load.

  When the elastic seal member 7 is maintained, since the body 4 is welded to the valve body member 12 with the first and second port forming members 13 and 14, the end 4a to which the driving means 2 of the body 4 is connected. The elastic seal member 7 is attached and detached through the opening. Since the elastic seal member 7 is held by the valve seat portion 5 via the holding means 6 that is detachably attached to the valve seat forming portion 13c of the body 4, the drive means 2 is mounted together with the valve body 3 and the bellows 9. The elastic seal member 7 can be easily attached to and detached from the valve seat portion 5 by removing it from the body 4 and attaching and detaching the holding means 4 to and from the valve seat portion 5. That is, the elastic seal member 7 can be removed from the valve seat portion 5 by inserting a tool from the opening of the end portion 4a, loosening the fixing screw 6b, and removing the ring member 6a from the valve seat forming portion 13c. Further, the elastic seal member 7 and the ring member 6a can be mounted on the valve seat portion 5 by placing the elastic seal member 7 and the ring member 6a on the stepped portion 13g and fastening the fixing screw 6b to the screw hole 13i. Therefore, the vacuum valve 1A of the present embodiment can easily maintain the elastic seal member 7 and the like.

  In the vacuum valve 1A, the valve seat surface 5a is provided at the same height as the bottom portion 14b of the second port 14a, and the elastic seal member 7 is disposed at substantially the same height as the bottom portion 14b of the second port 14a. Therefore, for example, when the reaction gas enters and solidifies in the gap between the dovetail groove 15 and the elastic seal member 7 and it is difficult to remove the elastic seal member 7, the ring member 6a is removed from the valve seat forming portion 13c. It is also possible to insert a tool from the second port 14a and peel the elastic seal member 7 from the step portion 13g.

  Further, in the vacuum valve 1 </ b> A, the outer diameter dimension C of the sealing surface 3 a of the valve body 3 is smaller than the outer diameter dimension D of the bottom portion of the dovetail groove 15. On the other hand, when the elastic seal members 115 and 212 are attached to the valve bodies 112 and 210 as in the first and second conventional examples shown in FIGS. 26 and 27, for example, the outer diameter of the sealing surface of the valve bodies 112 and 210 is It must be larger than the outer diameter of the bottom of the dovetail. Therefore, if the seal diameter is the same, the elastic seal member 7 is attached to the valve seat portion 5 as in the vacuum valve 1A, and the elastic seal member 115 is attached to the valve bodies 112 and 210 as in the first and second conventional examples. , 212 can be attached, the outer diameter C of the valve body 3 can be made smaller. When the outer diameter C of the valve body 3 is reduced, the reaction gas that has passed through the elastic seal member 7 immediately flows out to the valve chamber 12a, so that the pressure in the vicinity of the elastic seal member 7 can be reduced. As shown in FIG. 30, when the pressure decreases, the sublimation amount increases even at the same heating temperature. Therefore, the vacuum valve 1 </ b> A of the present embodiment can easily sublimate the reaction gas near the elastic seal member 7 and suppress the by-product from adhering to the elastic seal member 7.

  In particular, the vacuum valve 1A is provided with a bulging portion 13d on the inner peripheral surface of the opening portion where the valve seat portion 5 opens into the valve chamber 12a, and the bulging portion is thickened in the radial direction of the valve seat portion 5. The dovetail groove 15 is formed on 13d. Therefore, for example, the dovetail groove 15 in which the elastic seal member 7 is mounted so as to have the same seal diameter as when the elastic seal member 115 is provided on the valve body 112 as in the vacuum valve 101 of the first conventional example shown in FIG. Can be formed. Therefore, according to the vacuum valve 1A, the valve body 3 can be made compact.

  Moreover, since the valve seat surface 5a is provided at the same height as the bottom portion 14b of the second port 14a provided in the direction orthogonal to the axis of the valve chamber 12a, the vacuum valve 1A is provided in the first port 13a. The supplied reaction gas can easily change the flow along the seal surface 3a of the valve body 3 to the second port 14a. Therefore, the vacuum valve 1A can increase conductance as compared with the case where the valve seat 112 is provided at a position lower than the second port forming member 122 as in the vacuum valve 101 shown in FIG. As the conductance increases, the pressure near the elastic seal member 7 decreases. Therefore, the vacuum valve 1 </ b> A can easily sublimate the reaction gas flowing in the vicinity of the elastic seal member 7, and can suppress the by-product from adhering to the elastic seal member 7.

(About flow analysis)
In order to confirm the effect of the vacuum valve 1 </ b> A, the inventors flow about Example 1 in which the elastic seal member 7 is provided in the valve seat portion 5 and a comparative example in which the elastic seal member 1007 is provided in the valve body 1003. Analysis was performed.

  Example 1 corresponds to the vacuum valve 1A, the inner diameter A of the first port 13a is 80 mm, the inner diameter of the bulging portion 13d (the inner diameter of the opening of the valve seat surface 5a) B is 75 mm, and the valve body The outer diameter C of 3 was set to 91 mm.

FIG. 4 is a cross-sectional view showing a valve structure of a comparative example.
The vacuum valve 1001 of the comparative example is configured in the same manner as in Example 1 except for the valve seat 1005 and the valve body 1003. The vacuum valve 1001 is provided flat on a closing wall 1006 provided at a position where the valve seat surface 1005 is lower than the bottom portion 14b of the second port 14a. In the valve body 1003, a valve body member 1003b is fixed to a valve disk 1003a to which a lower end portion 9b of the bellows 9 is welded by a bolt 1003c. The elastic seal member 1007 is mounted in a dovetail groove 1015 formed between the valve disc 1003a and the valve body member 1003b. In the comparative example, the inner diameter A1 of the first port 13a is set to 80 mm, which is the same as that of the first embodiment, the opening inner diameter B1 of the valve seat 1005 is the same as that of the first port 13a, and the outer diameter C1 of the valve body 1003 is It is set to 99 mm, which is larger than the outer diameter C of the valve body 3 of the first embodiment.

  The flow analysis uses the analysis software “SCRYU”, and the speed and pressure when the reaction gas is supplied to the first port 13a at a predetermined pressure with the comparative example and Example 1 fully opened (opening degree 100%). The distribution of was examined. Further, the speed and pressure distribution when the reaction gas was supplied to the first port 13a at a predetermined pressure in a state where the comparative example and Example 1 were opened at a degree of opening of 60% with respect to the full opening were examined.

(Comparison of flow velocity when fully open)
FIG. 5 shows the result of analyzing the flow velocity distribution when the comparative example is fully opened. FIG. 7 shows the result of analyzing the flow velocity distribution when Example 1 is fully opened.
In Example 1, the reaction gas is accelerated when passing through the bulging portion 13d, as indicated by R3 in FIG. On the other hand, in the comparative example, the reactive gas is accelerated in the vicinity of 1003d of the valve body 1003 shown in R2 of FIG. 5 rather than in the vicinity of the opening of the valve seat surface 1005 shown in R1 of FIG. In Example 1, the flow velocity between the valve seat surface 5a shown in R4 of FIG. 5 and the seal surface 3a is faster than the flow velocity between the valve seat surfaces 1005 and 1003d of the comparative example shown in R2 of FIG. . Further, in Example 1, the flow velocity in the vicinity of the elastic seal member 7 indicated by Q3 in FIG. 7 is slower than the flow velocity in the vicinity of the elastic seal member 1007 indicated by Q1 in FIG. The average flow velocity in the vicinity of the elastic seal member 7 indicated by Q3 in FIG. 7 was about 1/6 with respect to the average flow velocity in the vicinity of the elastic seal member 1007 indicated by Q1 in FIG.

  From these facts, it was found that in Example 1, the elastic seal member 7 was not easily exposed to the reaction gas supplied to the first port 13a from the elastic seal member 1007 of the comparative example while securing a larger conductance than the comparative example. .

(Comparison of pressure when fully open)
FIG. 6 shows the result of analyzing the pressure distribution when the comparative example is fully opened. FIG. 8 shows the result of analyzing the pressure distribution when Example 1 is fully opened.
The pressure in the vicinity of the elastic seal member 7 indicated by Q4 in FIG. 8 is smaller than the pressure in the vicinity of the elastic seal member 1007 indicated by Q2 in FIG. The average pressure near the elastic seal member 7 indicated by Q4 in FIG. 8 was about 1/3 of the average pressure near the elastic seal member 1007 indicated by Q2 in FIG. As shown in FIG. 30, if the pressure is low, sublimation is possible even at a low heater temperature. Therefore, it turned out that Example 1 is easier to sublimate the reaction gas than the comparative example.

(Comparison of flow velocity at 60% opening)
FIG. 9 shows the result of analyzing the flow velocity distribution when the comparative example is opened with a valve opening of 60% with respect to full opening. FIG. 11 shows the results of analyzing the flow velocity distribution when Example 1 was opened with a valve opening of 60% with respect to the fully opened state.
As shown in R11 of FIG. 9 and R12 of FIG. 11, in Example 1, the flow velocity between the seal surface 3a and the valve seat portion 5 is faster than the flow velocity between the valve seat surfaces 1005 and 1003d of the comparative example. . Therefore, it can be seen that Example 1 has a larger conductance than the comparative example even when the valve opening is small.

  In Example 1, the flow velocity in the vicinity of the elastic seal member 7 indicated by Q7 in FIG. 11 is slower than the flow velocity in the vicinity of the elastic seal member 1007 in the comparative example indicated by Q5 in FIG. Therefore, according to the valve structure of Example 1, it has been found that even when the valve opening is reduced, the elastic seal member 7 is less exposed to the reaction gas than the elastic seal member 1007 of the comparative example, as in the fully opened state. .

(Comparison of pressure at 60% opening)
FIG. 10 shows the result of analyzing the pressure distribution when the comparative example is opened with a valve opening of 60% with respect to full opening. FIG. 12 shows the result of analyzing the pressure distribution when Example 1 was opened with a valve opening of 60% with respect to full opening.
Since Example 1 has a larger conductance than the comparative example, the pressure in the vicinity of the elastic seal member 7 of Example 1 shown in Q8 of FIG. 12 is smaller than the pressure in the vicinity of the elastic seal member 1007 of the comparative example shown in Q6 of FIG. Moreover, in the comparative example, as indicated by Q2 in FIG. 6 and Q6 in FIG. 10, the pressure in the vicinity of the elastic seal member 1007 increases as the valve opening decreases. However, in Example 1, as indicated by Q4 in FIG. 8 and Q8 in FIG. 12, the pressure in the vicinity of the elastic seal member 7 is substantially the same even when the valve is fully open or when the valve opening is 60% of the valve fully open. Therefore, it was found that Example 1 can obtain the effect of reducing the pressure in the vicinity of the elastic seal member 7 even if the valve opening is reduced. In Example 1, it was found that even when the valve opening was small, the reaction gas was more easily sublimated than the comparative example, and the by-product was less likely to adhere to the elastic seal member 7.

(Discussion)
From the above flow analysis, if the elastic seal member 7 is provided in the valve seat portion 5, the valve seat surface 5a is made higher than the bottom portion 14b of the second port 14a, and the bulging portion 13d is provided, a large conductance can be secured, It was found that the flow velocity and pressure near the elastic seal member 7 can be reduced regardless of the valve opening.

(Examination of valve body)
Next, in order to study the influence of the shape of the valve body 3 on the flow velocity and pressure, simulations were performed on Examples 1 and 2.

  FIG. 13 is a cross-sectional view showing the valve structure of the second embodiment. The vacuum valve 2001 of the second embodiment is different from the first embodiment only in that the outer diameter C2 of the valve body 2003 is larger than the outer diameter 3 of the valve body 3. The outer diameter C2 of the valve body 2003 is set to 99 mm.

  The simulation uses the analysis software “SCRYU”, and the flow rate when the reaction gas is supplied to the first port 13a at a predetermined pressure in the state where the first and second embodiments are opened at a degree of opening of 2% with respect to the fully open state. Distribution and pressure distribution were analyzed respectively.

(Comparison of flow rate)
FIG. 14 shows the results of analyzing the flow velocity distribution when Example 2 was opened with a valve opening of 2% with respect to the opening when fully opened. FIG. 16 shows the results of analyzing the flow velocity distribution when Example 1 was opened with a valve opening of 2% with respect to the opening when fully opened.
The flow rate near the elastic seal member 7 of Example 1 shown in Q11 of FIG. 16 is slower than the flow rate near the elastic seal member 7 of Example 2 shown in Q9 of FIG. This is because the distance L2 from the opening portion of the valve seat 5 in Example 2 to the outer periphery of the valve body 2003 is longer than the distance L1 from the valve seat 5 in Example 1 to the outer periphery of the valve body 3, This is probably because the gas is easily accelerated.

(Pressure comparison)
FIG. 15 shows the result of analyzing the pressure distribution when Example 2 was opened with a valve opening of 2% with respect to the opening when fully opened. FIG. 17 shows the result of analyzing the pressure distribution when Example 1 was opened with a valve opening of 2% with respect to the opening when fully opened.
The pressure on the secondary side (second port 14a side) of the elastic seal member 7 in Example 1 shown in Q12 of FIG. 17 is the secondary side (second side) of the elastic seal member 7 in Example 2 shown in Q10 of FIG. Lower than the pressure on the port 14a side). In the first embodiment, since the outer diameter C of the valve body 3 is smaller than the outer diameter C2 of the valve body 2003 of the second embodiment, the reaction gas that has passed through the elastic seal member 7 is earlier than the second embodiment. This is considered to flow out to 12a.

(Discussion)
From the above flow analysis, if the outer diameter C of the valve body 3 is reduced, a large conductance can be secured, and the flow rate and pressure in the vicinity of the elastic seal member 7 are reduced so that by-products adhere to the elastic seal member 7. It was found that it can be suppressed.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings.
In the vacuum valve of the second embodiment, a protrusion is provided in an annular shape on the valve body so as to protrude inside the bulging portion provided in the valve seat forming portion, and is formed between the protruding portion and the bulging portion. The point which comprises the aperture | diaphragm | squeeze part which restrict | squeezes the flow volume of a reactive gas with the clearance gap formed differs from the vacuum valve 1A of 1st Embodiment.

  In the vacuum valve according to the second embodiment, when the valve opening is small, the outer peripheral surface of the protrusion provided on the valve body faces the bulging portion to form a throttle portion. In the meantime, the reaction gas is reduced in flow rate and pressure by the throttle portion, and then passes between the elastic seal member and the valve body. Therefore, in the vacuum valve of the second embodiment, even when the valve opening is small, the reaction gas flowing in the vicinity of the elastic seal member is more easily sublimated than the vacuum valve 1A of the first embodiment, and the sealing performance can be maintained for a long time.

(About flow analysis of Examples 3 and 4)
The inventors conducted a flow analysis for verifying the effect of the throttle portion. The simulation uses the analysis software “SCRYU”, and the reaction gas is supplied to the first port 13a at a predetermined pressure with the third and fourth embodiments opened at a valve opening of 2% with respect to the fully open state. The flow velocity distribution and pressure distribution in were analyzed.

FIG. 18: is sectional drawing which shows the valve structure of Example 3 corresponding to the vacuum valve which concerns on 2nd Embodiment of this invention. FIG. 20 shows the result of analyzing the flow velocity distribution when the opening degree of Example 3 is 2%. FIG. 21 shows the result of analyzing the pressure distribution when the opening degree of Example 3 is 2%.
As shown in FIG. 18, the vacuum valve 3001 according to the third embodiment is different from the first embodiment in that the valve body 3003 is provided with a projecting portion 3003b projecting in an annular shape on the seal surface 3003a. 1 and in common. A gap S1 (an example of a throttle portion) is formed in an annular shape between the protrusion 3003b and the bulging portion 13d.

  As shown in FIG. 20, the protrusion 3003b has a radial width dimension W1 of the gap S1 that is smaller than a separation distance W2 (see FIG. 18) between the seal surface 3003a and the valve seat surface 5a when the valve is closed. The outer diameter dimension E is set. This is because the throttle function is exhibited from when the elastic deformation amount of the elastic seal member 7 is controlled to control the minute flow rate, and the flow velocity and pressure of the reaction gas flowing in the vicinity of the elastic seal member 7 are reduced. As shown in FIGS. 18, 20, and 21, the height of the protrusion 3003 b is controlled so that the flow rate is small from when the valve is closed until when the valve is opened so that the seal surface 3003 a is slightly separated from the elastic seal member 7. Is set so that the protrusion 3003b is disposed inside the bulging portion 13d during the period (for example, between 0% to 10% of the valve opening degree with respect to full opening). This is to increase the sublimation amount of the reaction gas when the valve opening is small while ensuring conductance. Further, the protrusion 3003b is provided with a tapered surface 3003c along the outer periphery of the tip, and increases the flow rate as the valve opening increases. This is to ensure conductance.

FIG. 19: is sectional drawing which shows the valve structure of Example 4 corresponding to the vacuum valve which concerns on 2nd Embodiment of this invention. FIG. 22 shows the result of analyzing the flow velocity distribution when the opening degree of Example 4 is 2%. FIG. 23 shows the result of analyzing the pressure distribution when Example 4 was set at an opening degree of 2%.
As shown in FIG. 19, the vacuum valve 4001 of the fourth embodiment is different from that of the first embodiment only in the configuration in which the valve body 4003 includes the throttle portion 4003 e, and the other configurations are common to the first embodiment.

  In the valve body 4003, a projecting portion 4003b is provided in a ring shape on the seal surface 4003a, and an o-ring 4003d is installed in a mounting groove 4003c formed on the outer peripheral surface of the projecting portion 4003b, thereby forming a throttle portion 4003e. ing. The O-ring 4003d is preferably mounted so as to contact the inner wall of the bulging portion 13d so as to cause fluid leakage, or to form a gap S2 with the bulging portion 13d. In the fourth embodiment, the latter is adopted.

  As shown in FIGS. 22 and 23, the outer diameter dimension F of the mounting protrusion 4003b is smaller than the inner diameter dimension B of the bulging portion 13d. The radial width W3 of the gap S2 provided between the O-ring 4003d and the bulging portion 13d is smaller than the separation distance W4 (see FIG. 19) between the seal surface 4003a and the valve seat portion 5 when the valve is closed. It is attached to the attachment protrusion 4003b. Since the O-ring 4003d is elastically deformed, it is possible to provide the throttle portion 4003e by sharing the valve body 4003 between vacuum valves having different diameters.

(About analysis of flow velocity)
As shown in FIGS. 20 and 22, in the third and fourth embodiments, the flow rate of the reaction gas flowing between T3 and T5 between the sealing surfaces 3003a and 4003a and the elastic seal member 7 is the same as that of the first embodiment shown in FIG. It is slower than the flow rate of T1 between the surface 3a and the elastic seal member 7.

(About pressure analysis)
As shown in FIGS. 21 and 23, in Examples 3 and 4, the pressure between T4 and T6 between the seal surfaces 3003a and 4003a and the elastic seal member 7 is elastic with the seal surface 3a of Example 1 shown in FIG. It is lower than the pressure of T2 between the members 7.

(Discussion)
From the above flow analysis, if a clearance S1 (an example of a throttle part) and a throttle part 4003e are provided on the first port 13a side of the elastic seal member 7, the flow velocity and pressure near the elastic seal member 7 even when the valve opening is small. It was found that the reaction gas flowing in the vicinity of the elastic seal member 7 is easily sublimated.

(Third embodiment)
Subsequently, a third embodiment of the present invention will be described. FIG. 24 is a sectional view showing a valve structure of a vacuum valve 1B according to the third embodiment of the present invention. In FIG. 24, the heater 10 is not shown.
The vacuum valve 1B of the third embodiment is configured in the same manner as the vacuum valve 1A of the first embodiment except for the throttle portion 37. Here, it demonstrates centering on the point which is different from the vacuum valve 1A of 1st Embodiment, and abbreviate | omits description which is common in the vacuum valve 1A of 1st Embodiment suitably.

  The throttle portion 37 is provided on the radially inner side (on the first port 13a side) with respect to the elastic seal member 7. The restricting portion 37 includes an annular protrusion 35 provided annularly so as to protrude toward the valve body 3 at a position inside the stepped portion 13g with respect to the valve seat forming portion 13c, and an annular protrusion 35 when the valve is closed. An annular groove 34 is formed in an annular shape on the seal surface 3a of the valve body 3 so as to be fitted with a gap S3 therebetween. The inner wall of the annular protrusion 35 and the annular groove 34 is provided with a taper for easy fitting.

  As in the first embodiment, the holding means 31 is configured by detachably attaching the ring member 32 to the valve seat forming portion 13 c of the body 4 with a fixing screw 33. The ring member 32 is thicker than the ring member 6a of the first embodiment so that the surface located on the valve body 3 side has the same height as the annular protrusion 35.

  In the valve body 3, a pressing portion 36 provided outside the annular groove 34 is inserted between the annular protrusion 35 and the ring member 32 and sealed to the elastic seal member 7.

  When such a vacuum valve 1B performs minute flow control, the flow rate and pressure of the reaction gas supplied to the first port 13a is reduced by the restricting portion 37 to reduce the flow velocity and pressure. It passes between the sealing surface 3a. Therefore, the vacuum valve 1B exhibits the same effects as the clearance S1 and the throttle portion 4003e of the third and fourth embodiments.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. FIG. 25 is a cross-sectional view showing a valve structure of a vacuum valve 1C according to the fourth embodiment of the present invention.
The vacuum valve 1 </ b> C is configured similarly to the vacuum valve 1 </ b> A of the first embodiment except for the configuration of the valve seat portion 46. Here, it demonstrates centering on the point which is different from 1A of vacuum valves, and abbreviate | omits description suitably about the point which is common with 1A of vacuum valves.

  The first port forming member 45 is different from the first port forming member 13 of the first embodiment only in that the valve seat forming portion 13c is not provided. The valve seat portion 46 is configured by attaching the holding means 40 to the closing wall 13h.

  The holding means 40 is detachably attached to the first port forming member 45 by fastening a fixing screw 42 inserted through the ring member 41 into a screw hole 13 i formed in the closing wall 13 h of the first port forming member 45. Yes.

  The ring member 41 has a flat end surface located on the valve body 3 side, and constitutes a valve seat surface 41a. The thickness of the ring member 41 is set in the axial direction (vertical direction in the drawing) so that the valve seat surface 41a is at the same height as the bottom portion 14b of the second port 14a in a state of being attached to the closing wall 13h. Yes. The inner peripheral surface of the ring member 41 includes a bulging portion 41b that protrudes radially inward from the inner wall 13f of the first port 13a. That is, the inner diameter dimension B of the opening portion of the valve seat surface 41a is smaller than the inner diameter dimension A of the first port 13a. The tapered surface 41c connects the bulging portion 41b to the inner wall 13f and smoothly contracts the reaction gas supplied to the first port 13a toward the bulging portion 41b.

  The ring member 41 has a dovetail groove 41d formed in the valve seat surface 41a, and the elastic seal member 7 is mounted in the dovetail groove 41d so as to be elastically deformable. That is, the elastic seal member 7 is attached to the valve seat portion 46 while being held by the holding means 40. The dovetail groove 41d is provided on an extension line obtained by extending the inner wall 13f of the first port 13a toward the valve body 3, and makes the valve body 3 more compact than the case where the elastic seal member 7 is attached to the seal surface 3a. In the ring member 41, an annular groove 41f is formed on an end surface 41e located on the opposite side of the end surface on which the dovetail 41d is formed, and an O-ring 43 is attached. The O-ring 43 is crushed between the ring member 41 and the closing wall 13h by the fastening force of the fixing screw 42 to prevent fluid leakage.

In such a vacuum valve 1C, the valve seat portion 46 functions in the same manner as the valve seat portion 5 of the first embodiment, and has the same effects as the vacuum valve 1A of the first embodiment. Since the shape of the first port forming member 45 is simpler than the shape of the first port forming member 13 of the first embodiment, the production cost of the vacuum valve 1C can be reduced compared to the vacuum valve 1a of the first embodiment.
Further, since the vacuum seal 1C has the elastic seal member 7 attached to the holding means 40 that is detachably provided on the port forming member 45, for example, if the fixing member 42 is loosened and the entire ring member 41 is replaced, The elastic seal member 7 can be easily replaced.
Further, since the vacuum valve 1C fastens the fixing screw 42 in the valve closing direction, the fixing screw 42 is not required to have a strength against a seal load.

In addition, this invention is not limited to the said embodiment, Various application is possible.
For example, it goes without saying that the vacuum valve of the above embodiment may be applied to other devices of the semiconductor manufacturing apparatus.

1A, 1B, 1C, 2001, 3001, 4001 Vacuum valve 2 Driving means 3 Valve body 4 Body 5, 46 Valve seat (an example of valve seat)
6, 31, 40 Holding means 7 Elastic seal member 10 Heater 12 Valve body member (an example of valve body)
13, 45 1st port formation member (an example of the 1st port part)
14 Second port forming member (example of second port portion)
15,41d Dovetail groove 37,4003e Restriction portion S1 Clearance (an example of an restriction portion)
C Outer diameter D of valve body D Outer diameter of dovetail bottom

Claims (4)

A first port portion and a second port portion integrally projecting from the valve body portion, a body through which a reaction gas flows, a valve seat provided in the body, and a valve body that contacts or separates from the valve seat; An elastic seal member that is crushed between the valve body and the valve seat and elastically deformed; a driving unit that is connected to the body and applies a driving force to the valve body; and a heater that heats the body. In the vacuum valve,
The elastic seal member is mounted on the valve seat;
A holding means for detachably attaching to the inner wall of the body and holding the elastic seal member;
A vacuum valve characterized by The vacuum valve according to claim 1,
The valve seat has a dovetail groove in which the elastic seal member is mounted;
The said valve body is a vacuum valve characterized by the outer diameter dimension of the sealing surface closely_contact | adhered to the said elastic seal member being below the outer diameter dimension of the bottom part of the said dovetail groove. The vacuum valve according to claim 2,
The valve seat has a bulging portion projecting radially inwardly on an inner peripheral surface of an opening that opens on the valve body side;
The vacuum valve, wherein the dovetail groove is formed in the valve seat so as to project toward the bulging portion. The vacuum valve according to any one of claims 1 to 3,
A vacuum valve having a throttle portion provided inside the elastic seal member.