JP4395652B2 - Chemical control valve - Google Patents

Description

  The present invention relates to a chemical control valve that controls supply of a chemical used in a semiconductor manufacturing apparatus or the like. More specifically, the present invention relates to a chemical control valve that can improve the sealing performance of the external seal structure in the chemical control valve.

  2. Description of the Related Art Conventionally, in a chemical control valve for controlling the supply of a chemical solution used in a semiconductor manufacturing apparatus or the like, the sealing performance in an external seal structure is regarded as important because of the nature of the chemical solution to be controlled. In a general external seal structure, the peripheral edge of the diaphragm provided in the chemical control valve is press-fitted into a seal groove provided in the body, and the diaphragm is elastically deformed to generate internal stress in the diaphragm to ensure the sealing performance. is doing.

  One of the chemical control valves having such an external seal structure is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-247650. This chemical control valve includes a fluororesin diaphragm provided at a lower end of a rod, a valve seat to which the diaphragm is closely attached and separated, an inflow passage and an outflow passage communicating with the valve seat, the valve seat, and the A fluororesin body in which the inflow path and the outflow path are formed; and a seal groove formed in the body so as to surround the valve seat; and a peripheral protrusion of the diaphragm as the seal groove In the chemical control valve that performs external sealing by sandwiching between the cylinder and the body while being press-fitted, the chemical control valve includes a first annular protrusion formed on a side surface of the peripheral protrusion of the diaphragm, and the peripheral protrusion of the diaphragm In the state of being press-fitted into the seal groove, the first annular protrusion presses a part of the side surface of the seal groove, thereby generating an internal stress generated in the peripheral protrusion of the diaphragm. While giving a peak value, the inner wall portion of the seal groove is reduced in thickness by reducing the width of the seal groove without changing the sum of the thickness of the inner wall portion of the seal groove and the width of the seal groove. It is characterized by an increase. As a result, the sealing ability is further enhanced, and further safety of the external seal structure can be secured.

JP 2003-247650 A (pages 3-4, FIG. 1)

  However, in the chemical solution control valve disclosed in the above Japanese Patent Application Laid-Open No. 2003-247650, the sealing performance in the external seal structure may not be sufficient. In recent years, semiconductor devices are increasingly handling highly permeable chemical solutions at high temperatures as device integration increases. Highly permeable chemical solutions include dangerous substances such as hydrofluoric acid. ing. Thus, in recent years, since the frequency with which chemical liquid control valves are used under conditions that are severer than before has increased, there is a possibility that the sealing performance of the external seal structure may not be sufficient. For this reason, further improvement in sealing performance is desired for the external seal structure of the chemical liquid control valve so that sufficient safety can be ensured even under severer conditions than before.

  Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a chemical control valve that can improve the sealing performance in the external seal structure.

The chemical control valve according to the present invention, which has been made to solve the above-mentioned problems, includes a fluororesin valve element provided at the lower end of a rod that slides in a cylinder, and a valve seat in which the valve element adheres and separates. In the chemical control valve having an inflow path and an outflow path communicating with the valve seat, and a fluororesin body formed with the inflow path, the outflow path, and the valve seat, the cylinder and the body The valve body includes a fixed portion fixed to the body, and a movable portion that moves as the rod slides, and the fixed portion has a peripheral protrusion. A stepped portion is formed at the tip of the peripheral protrusion, a peripheral protrusion is formed in the body, a step is formed at the tip of the peripheral protrusion, and the fixing portion Tip of the peripheral protrusion of the body and the peripheral protrusion of the body Grooves are formed by formed stepped portion, by fitting the welded parts in the groove, as well as welding and the said fixed part body, the peripheral projecting portion of the fixing portion, wherein the peripheral projecting portion of the body It is characterized by being sandwiched between spacers .
Note that PTFE (tetrafluoroethylene resin) or modified PTFE may be used as the material for the valve body, and PTFE, modified PTFE, or PFA (perfluoroalkoxy resin) may be used as the material for the body.

  Since this chemical control valve has a structure in which the body and the fixed portion of the valve body are welded or welded together, the external seal is performed by the internal stress of the diaphragm (the fixed portion of the valve body) as in the prior art. Higher sealing performance can be obtained compared to the case.

  The valve body includes a diaphragm valve body and a bellows valve body. In the case of the diaphragm valve body, the fixed portion of the valve body corresponds to the outer peripheral edge portion of the diaphragm, and the movable portion of the valve body corresponds to the valve body portion and the thin portion. On the other hand, in the case of the bellows valve body, the fixed portion of the valve body corresponds to the bellows adapter, and the movable portion of the valve body corresponds to the valve body portion and the bellows.

  In the chemical control valve according to the present invention, it is desirable that the body and the fixed portion are welded or welded by a fluororesin welding member or a welding rod having a property of melting and flowing when heated to the melting point.

  When both the body and the valve body are made of PTFE, they cannot be welded or welded. This is because PTFE does not flow even when heated to a melting point (327 ° C.) or higher. Therefore, in this chemical solution control valve, the body and the fixed portion of the valve body are welded or welded using a fluororesin welding part or welding rod having a property of melting and flowing when heated to the melting point. When the welded part or the welded part is heated, the fluororesin having a property of melting and flowing when heated to the melting point can be melted and joined together. Therefore, even if both the body and the valve body are made of PTFE, they can be reliably welded or welded.

  And when using a welding component, it is desirable to form the groove | channel for inserting the said welding component in the welding part of the said fixing | fixed part and the said body. This is because the welding area can be increased while reducing the size of the welded portion, so that a large bonding force can be obtained while minimizing deformation of the member due to the thermal effect during welding. As a result, the sealing performance can be improved.

  In the chemical control valve according to the present invention, it is desirable that the fixed portion is held between the cylinder and the body. Thereby, since the welded portion or the welded portion is hardly affected by the operation of the valve body, the reliability of the external seal can be improved. In addition, since a conventional external seal mechanism can be provided, the external seal has a double seal structure, and the sealing performance can be further improved.

  Moreover, in the chemical | medical solution control valve which concerns on this invention, it is desirable to have the spacer arrange | positioned between the said cylinder and the said body, and the elastic body arrange | positioned between the said spacer and the said cylinder.

  When controlling high-temperature chemicals, even if the body and diaphragm valve body undergoes thermal contraction and the force to pinch the diaphragm valve body between the body and the cylinder weakens, This is because the pinching force can be supplemented, and thereby the diaphragm valve body can be firmly fixed.

  And the above-mentioned chemical | medical solution control valve is suitable for controlling supply of the chemical | medical solution used with a semiconductor manufacturing apparatus.

  According to the chemical control valve according to the present invention, since the external sealing is performed by welding or welding the fluororesin body and the fixing portion of the fluororesin valve body, the sealing performance in the external seal structure is improved. Can be improved.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a most preferred embodiment embodying a chemical liquid control valve of the present invention will be described in detail based on the drawings. In the present embodiment, a chemical liquid control valve that includes a diaphragm valve body and is used to control a chemical liquid in a semiconductor manufacturing apparatus is illustrated. 1 and 2 show a schematic configuration of the chemical control valve according to the present embodiment. FIG. 1 is a cross-sectional view of the chemical control valve. FIG. 2 is an enlarged view of an external seal portion in the chemical liquid control valve shown in FIG.

  As shown in FIG. 1, the chemical control valve 1 includes a base plate 2, a body 3, a cylinder 9, and a spacer 15. The body 3 is fixed to the base plate 2, and a cylinder 9 is connected to the body 3 via a spacer 15. An annular groove is formed on the upper surface (cylinder side) of the spacer 15, and an O-ring 16 is fitted in the groove.

  In the body 3, an inflow path 31 and an outflow path 32 are formed. An inflow port 6 to which the joint 7 is screwed is formed at one end of the inflow path 31, and an outflow port 4 to which the joint 5 is screwed is formed at one end of the outflow path 32. A valve seat 19 is formed at the other end of the inflow passage 31 on the upper surface of the body 3. In this embodiment, the valve seat 19 has a flat shape and the portion of the diaphragm valve body 8 that contacts the valve seat 19 has a convex shape. However, the valve seat 19 has a convex shape and the diaphragm valve body side has a flat shape. You can also.

  On the other hand, a piston rod 10 is housed in the cylinder 9. A cover 13 provided with a ventilation port 14 is attached to the top of the cylinder 9. In the upper space of the cylinder 9 formed by the cover 13 and the piston rod 10, a spring 12 that urges the piston rod 10 downward is inserted. On the other hand, an operation port 11 communicating with the lower space of the cylinder 9 formed by the piston rod 10 is attached to the lower portion of the cylinder 9. A diaphragm valve body 8 is screwed to the lower end of the piston rod 10. The diaphragm valve body 8 includes a valve body portion 8 a and a thin wall portion 8 b that move as the rod 10 slides, and a peripheral edge portion 22 that is fixed to the body 3. The valve body portion 8a and the thin portion 8b correspond to the “movable portion” of the present invention, and the peripheral portion 22 corresponds to the “fixed portion” of the present invention.

  In consideration of the property of the chemical to be controlled used in the semiconductor manufacturing apparatus, PFA, PTFE, which has excellent corrosion resistance among fluororesins, can be used as the material of the parts to be in contact with liquid such as the diaphragm valve body 8 and the body 3. Modified PTFE is used. In the present embodiment, “modified PTFE” is used as the material of the body 3 and the diaphragm valve body 8. This is because PFA cannot sufficiently satisfy the functional requirements of the valve body, and PTFE has poor welding power compared to modified PTFE.

  As shown in FIG. 2, a peripheral protrusion 22 a is formed on the peripheral portion 22 of the diaphragm valve body 8. A stepped portion 24 is formed at the tip of the peripheral protrusion 22 a of the diaphragm valve body 8. Further, in order to support the peripheral protrusion 22 a of the diaphragm valve body 8, an annular protrusion 3 a is formed on the body 3. A step portion 25 is formed at the tip of the protruding portion 3 a of the body 3. These step portions 24 and 25 form a groove 26 for fitting a welding part 23 made of fluororesin (PFA) for welding the distal end portions of the peripheral protrusion 22a of the diaphragm valve body 8 and the protrusion 3a of the body 3. Has been.

  The peripheral protrusion 22a of the diaphragm valve 8 and the protrusion 3a of the body 3 are welded by the welding component 23 at the tip of the peripheral protrusion 22a of the diaphragm valve 8 and the protrusion 3a of the body 3. A welded portion is formed. Thus, by forming the welded portion at the tip of the peripheral protrusion 22a of the diaphragm valve body 8, the welded portion can be hardly affected by the operation of the diaphragm valve body 8, so that the outer seal Reliability can be increased.

  Here, the welding method will be briefly described. The welding of the peripheral protrusion 22a of the diaphragm valve body 8 and the protrusion 3a of the body 3 is performed using a metal jig (die) 40 as shown in FIG. FIG. 3 is a longitudinal sectional view of the mold. The mold 40 includes an upper surface portion 40a that contacts the upper surface of the welding portion and heats the welding component 23 from above, and a side surface portion 40b that heats the side surfaces of the welding portion (the body 3 side and the diaphragm valve body 8 side). I have. Thus, by providing the side surface portion 40b in the mold 40, heat can be efficiently transmitted to the welded portion. The side surface portion 40b serves as a stopper when the welded portion is thermally expanded and deformed.

  Then, the mold 40 is heated to about 400 ° C. and brought into contact with the welded portion, and the peripheral protrusion 22a of the diaphragm valve body 8 and the protrusion 3a of the body 3 are welded. When the heated mold 40 comes into contact with the welded portion, the temperature around the welded portion increases, and the welded part 23 having a lower melting point (around 305 ° C.) than the body 3 and the diaphragm valve body 8 starts to melt. Thereafter, the peripheral protrusion 22a of the diaphragm valve body 8 and the protrusion 3a of the body 3 reach the melting point (327 ° C.), but both the body 3 and the diaphragm valve body 8 are made of modified PTFE, so that they expand without flowing ( Begin to soften). As a result, the peripheral protrusion 22a of the diaphragm valve body 8 and the protrusion 3a of the body 3 and the welding component 23 are melted and the welding is completed.

  The welding time is about 4 to 5 minutes. After welding, the white modified PTFE body 3 and the diaphragm valve body 8 are changed to milky white transparent. By applying heat only to the periphery of the welded portion using the mold 40 in this way, adverse effects due to heat are exerted on the functional portion of the body 3 (valve seat 19 and the like) and the movable portion of the diaphragm valve body 8 (thin wall portion 8b). Welding can be performed without.

  Here, as shown in FIG. 2, the longitudinal cross-sectional shape of the groove | channel 26 is a substantially rectangular shape, The three sides become a welding location. Therefore, by forming such a groove 26, a large bonding force can be obtained while reducing the welded portion. As a result, the sealing performance of the external seal can be improved.

  The cylinder 9 and the body 3 are interposed through the spacer 15 in a state where the peripheral protrusion 22a of the welded diaphragm valve body 8 and the protrusion 3a of the body 3 are press-fitted into a groove 15a formed in the spacer 15. As a result, the diaphragm valve body 8 is sandwiched and fixed between the body 3 and the spacer 15. At this time, a slight gap is formed between the welded portion between the peripheral protrusion 22 a of the diaphragm valve body 8 and the protrusion 3 a of the body 3 and the groove 15 a of the spacer 15. Thereby, the diaphragm valve body 8 can be firmly fixed by the spacer 15 without being affected by the deformation of the welded portion.

  Further, since the O-ring 16 is provided in the spacer 15, when the high-temperature chemical solution is controlled, the body 3 and the diaphragm valve body 8 are subjected to thermal contraction, and the body 3 and the cylinder 9 cause the diaphragm valve body 8 to move. Even if the holding force becomes weak, the holding force between the body 3 and the cylinder 9 can be supplemented by the elastic force of the O-ring 16. Thereby, the diaphragm valve body 8 can be firmly fixed even under high temperature.

  Here, the external seal structure of the chemical liquid control valve 1 will be described. The outer seal of the chemical control valve 1 is such that when the peripheral protrusion 22a of the diaphragm valve 8 and the protrusion of the body 3 are press-fitted into the groove of the spacer 15, the peripheral protrusion of the diaphragm valve 8 having elasticity 22 a is compressed in the radial direction, and is performed by an internal stress generated inside the peripheral protrusion 22 a of the diaphragm valve body 8. This is the same method as the conventional external seal.

  Further, in the present embodiment, the peripheral protrusion 22a of the diaphragm valve 8 and the protrusion of the body 3 using the welded part 23 at the tip of the peripheral protrusion 22a of the diaphragm valve 8 and the protrusion 3a of the body 3. The external seal is performed by welding. That is, in this embodiment, double external sealing is performed. Thereby, the sealing performance of the external seal can be significantly improved.

  Next, the operation of the chemical liquid control valve 1 having the above configuration will be described. When compressed air is supplied to the lower space of the cylinder 9 via the operation port 11, the piston rod 10 moves upward due to the balance between the urging force of the spring 12 and the pressure of the compressed air, and the piston rod 10 moves to the lower end of the piston rod 10. The provided valve body 8 a of the diaphragm valve body 8 is separated from the valve seat 19. Thereby, the inflow path 31 and the outflow path 32 communicate.

  On the other hand, when the compressed air is exhausted from the lower space of the cylinder 9 via the operation port 11 of the body 3, the piston rod 10 moves downward due to the balance between the biasing force of the spring 12 and the pressure of the compressed air. The valve body portion 8 a of the diaphragm valve body 8 provided at the lower end of 10 is in close contact with the valve seat 19. Thereby, the inflow path 31 and the outflow path 32 are interrupted | blocked. In this manner, the chemical liquid control valve 1 controls the chemical liquid flowing from the inflow port 6 to the outflow port 4 via the valve seat 19. And in the chemical | medical solution control valve 1, since the peripheral protrusion part 22a of the diaphragm valve body 8 and the protrusion part 3a of the body 3 are welded by the welding component 23, and an external seal is performed and high sealing performance is ensured, it is severe. Even under conditions, the chemical solution does not leak out of the chemical solution control valve 1.

  As described above in detail, in the chemical control valve 1 according to the present embodiment, the external seal is obtained by welding the protruding portion 3a of the body 3 and the peripheral tip portion 22a of the diaphragm valve body 8 using the welding component 23. Therefore, it is possible to obtain a higher sealing performance as compared with the conventional case where external sealing is performed by the internal stress of the diaphragm valve body.

  In the chemical solution control valve 1, a step 24 is formed at the tip of the peripheral protrusion 22 a of the diaphragm valve body 8, and a step 25 is formed at the tip of the protrusion 3 a of the body 3. Thus, the groove 26 into which the welding component 23 is fitted is formed, so that the welding area can be increased while the welding portion is reduced. As a result, a large bonding force can be obtained while minimizing the deformation of the member by welding, and the sealing performance can be improved.

  Furthermore, in the chemical solution control valve 1, the spacer 15 having the O-ring 16 is disposed between the cylinder 8 and the body 3, so that the body 3 and the diaphragm valve body 8 are subjected to thermal contraction at a high temperature, Even if the force for pinching the diaphragm valve body 8 with the cylinder 9 becomes weak, the holding force between the body 3 and the cylinder 9 can be supplemented by the elastic force of the O-ring 16.

It should be noted that the above-described embodiment is merely an example and does not limit the present invention in any way, and various improvements and modifications can be made without departing from the scope of the invention .

In the embodiment noted above, although the cross-sectional shape of the groove 26 formed by the stepped portion 24 and the projecting portion 3a stepped portion 25 of the body 3 of the peripheral protrusion 22a of the diaphragm valve element 8 has a vertically long substantially rectangular, As shown in FIG. 5, it may be a horizontally long substantially rectangular shape, or may be a substantially square shape as shown in FIG .

Also, in the embodiment described above has exemplified a chemical solution control valve comprising a diaphragm valve body, the present invention can also be applied in the chemical control valve 1a comprising a bellows valve element 48, as shown in FIG. 11 . Here, the bellows valve body 48 includes a valve body portion 48a and a bellows 48b (corresponding to a movable portion), and a bellows adapter 48c (corresponding to a fixed portion). Then, the outer peripheral portion of the bellows adapter 48c and the body 3 may be welded by the welding component 23 to perform external sealing.

  In the above-described embodiment, the protruding portion 3a of the body 3 and the peripheral protruding portion 22a of the diaphragm valve body 8 are joined by welding to perform external sealing, but the protruding portion 3a of the body 3 and the diaphragm valve body It is also possible to perform external sealing by joining the eight peripheral protrusions 22a by welding.

(Reference example)
For example, in the above-described embodiment, the peripheral edge 22 of the diaphragm valve body 8 and a part of the body 3 are welded at a portion protruding to the cylinder 9 side (upward), but as shown in FIG. You may make it weld from a side surface (diameter direction of a diaphragm valve body), without forming a protrusion part as shown in FIG. In this case, welding is performed by bringing a heated metal jig (die) into contact with the portion indicated by x in FIG.

In the embodiment described above, the cross-sectional shape of the groove 26 formed by the step 24 of the peripheral protrusion 22a of the diaphragm valve body 8 and the step 25 of the protrusion 3a of the body 3 is a vertically long, substantially rectangular shape. As shown in FIG. 7, it may be a triangle.

Further, without forming the groove 26 for fitting the welded part 23, the welded part 23 is directly formed on the upper surface of the peripheral protrusion 22a of the diaphragm valve body 8 and the upper surface of the protruding part 3a of the body 3, as shown in FIG. Can also be welded.

  Further, when “PFA” is used as the material of the body 3, as shown in FIG. 9, a PTFE or modified PTFE ring 45 is disposed so as to cover the protruding portion 3 a of the body 3 from the outside. The welding may be performed using a metal jig (die) as shown in FIG. In this case, welding is performed at the portion marked with x shown in FIG.

  Furthermore, in the above-described embodiment, the spacer 15 is disposed between the cylinder 9 and the body 3, but as shown in FIG. 10, the cylinder 9 and the body 3 are connected without the spacer 15 being disposed. You can also. However, in this case, it is not suitable for controlling a high temperature chemical. This is because, when the body 3 and the diaphragm valve body 8 are subjected to thermal contraction at a high temperature, the force for pinching the diaphragm valve body 8 between the body 3 and the cylinder 9 becomes weak.

It is sectional drawing which shows schematic structure of the chemical | medical solution control valve which concerns on embodiment. It is an enlarged view of the external seal part in the chemical | medical solution control valve shown in FIG. It is sectional drawing which shows the metal jig | tool (metal mold | die) for performing welding. It is a figure which shows the reference example of a welding location. It is a figure which shows the modification of the groove | channel which inserts a welding component. It is a figure which shows the modification of the groove | channel which inserts a welding component. It is a figure which shows the reference example of the groove | channel which inserts a welding component. It is a figure which shows the reference example which does not provide the groove | channel which inserts a welding component. It is sectional drawing of the external seal part in the case of using the body made from PFA. It is a figure which shows the reference example which does not arrange | position a spacer. It is sectional drawing which shows schematic structure of a chemical | medical solution control valve provided with the bellows valve body to which this invention is applied.

DESCRIPTION OF SYMBOLS 1 Chemical | medical solution control valve 3 Body 3a Body protrusion part 8 Diaphragm valve body 8a Valve body part 8b Thin part 9 Cylinder 10 Piston rod 15 Spacer 16 O ring 19 Valve seat 22 Diaphragm valve body peripheral part 22a Diaphragm valve body peripheral protrusion 23 welding parts 26 groove

Claims (3)

A fluororesin valve body provided at the lower end of a rod that slides in the cylinder, a valve seat in which the valve body is closely contacted and separated, an inflow path and an outflow path communicating with the valve seat, the inflow path, In the chemical control valve having the outflow passage and the fluororesin body on which the valve seat is formed,
Having a spacer disposed between the cylinder and the body;
The valve body includes a fixed portion that is fixed to the body, and a movable portion that is movable as the rod slides,
A peripheral protrusion is formed on the fixed part, and a step is formed at the tip of the peripheral protrusion,
A peripheral protrusion is also formed in the body, and a step is formed at the tip of the peripheral protrusion,
A groove is formed by a step formed at the tip of the peripheral protrusion of the fixing part and the peripheral protrusion of the body, and a welding part is fitted into the groove to weld the fixing part and the body. ,
A chemical liquid control valve, wherein a peripheral protrusion of the fixed part is sandwiched between a peripheral protrusion of the body and the spacer . In the chemical control valve according to claim 1,
Chemical control valve which, comprising the placed elastic body between the front Symbol spacer and the cylinder. In the chemical liquid control valve according to claim 1 or 2,
A chemical solution control valve for controlling supply of a chemical solution used in a semiconductor manufacturing apparatus.

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