JP4970661B2 - Suck back valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a suck back valve used in a circuit for supplying a liquid such as a chemical solution to a semiconductor wafer in a semiconductor manufacturing apparatus, for example.
[0002]
[Prior art]
As a conventional suck back valve, a flow path for flowing a chemical solution such as a resist solution, a diaphragm for exposing the pressure receiving surface to the flow path for sucking back, and an operating body such as a piston for displacing the diaphragm There is. Such a suck-back valve is interposed, for example, between a coating nozzle for applying a chemical solution to a semiconductor wafer and a chemical solution supply source, and changes the volume of the flow path by displacing the diaphragm by the operating body. Yes. This prevents unnecessary chemical liquid from dripping from the nozzle onto the semiconductor wafer.
[0003]
Japanese Patent Application Laid-Open No. 7-77285 discloses an example of this type of suck back valve. As shown in FIG. 6, in this suck back valve, the diaphragm 54 is displaced by reciprocating the operating body 51 by the advancement and retraction of the output shaft 53 of the step motor 52. In this suck back valve, the outer diameter of the diaphragm 54 is set larger than the inner diameter of the flow path 55. The diaphragm 54 is disposed corresponding to a suck back chamber 56 provided in the middle of the flow path 55. Therefore, a part of the suck back chamber 56 constitutes an overhanging space that protrudes from both sides of the channel 55.
[0004]
Japanese Utility Model Publication No. 8-10399 (Japanese Utility Model Laid-Open No. 3-22570) discloses another example of this type of suck-back valve. As shown in FIG. 7, in this suck back valve, the diaphragm 54 is displaced by reciprocating a piston 57 as an operating body by a working fluid. In this suck back valve, the pressure receiving surface 54 a of the diaphragm 54 is disposed on the inner peripheral wall surface 55 a along the flow direction of the flow path 55. This prevents a dead space from being formed between the pressure receiving surface 54a of the diaphragm 54 and the inner peripheral wall surface 55a along the flow direction of the flow path 55, thereby preventing liquid accumulation and bubble accumulation due to the dead space.
[0005]
[Problems to be solved by the invention]
By the way, the conventional suck back valve shown in FIG. 6 has the suck back chamber 56 in the middle of the flow path 55, so that the overhanging space may become a bubble pool for the liquid flowing through the flow path 55. Was also considered. In the unlikely event that the overhanging space becomes a bubble pool, problems such as the stability of liquid suction during suckback and a decrease in the adjustment accuracy of the liquid flow rate become problems. For example, when a suck back valve is used between a chemical solution application nozzle and a chemical solution supply source, there is a possibility that the chemical solution may be cut off by the application nozzle or the adjustment of the chemical solution application amount may be affected. .
[0006]
Here, in the suck back valve, the liquid flows through the flow path 55 and passes through the suck back chamber 56, and it is difficult to actually think that the overhanging space becomes a bubble pool. However, in the conventional suck back valve, the mounting direction, the fluid supply pressure, and the like may be changed according to various use conditions. For example, in the conventional suck-back valve, FIG. 6 is set in the upright state, and the whole is rotated 90 degrees from the upright state and used in the vertical state, or in the inverted state where the whole is rotated 180 degrees from the upright state. Or use it. Due to the difference in these conditions, it is desirable that even if bubbles enter the overhanging space, they should be easily removed.
[0007]
Here, when the suck back valve is used in a vertical state, since the flow path 55 is arranged vertically, the bubbles flow vertically through the flow path 55 and do not accumulate in the overhanging space. On the other hand, when the suck back valve is used in an inverted state, the diaphragm 54 is positioned on the lower side and the bottom wall of the overhanging space is positioned on the upper side, and bubbles can be easily removed using this bottom wall. Is possible.
[0008]
On the other hand, the conventional suck back valve shown in FIG. 7 has a problem that a dead space is formed on the pressure receiving surface 54a of the diaphragm 54 when used in an upright state. The dead space was eliminated by arranging on 55a. Here, since the same thing can be considered for the conventional suck back valve shown in FIG. 6, the positional relationship between the diaphragm 54 and the flow path 55 arranged corresponding to the suck back chamber 56 is specified. It is desirable to keep it.
[0009]
The present invention has been made in view of the above circumstances, and a first object of the invention is to provide a suck-back valve that makes it possible to further improve bubble removal from around the diaphragm in an inverted state. It is in.
In addition to the first object, a second object of the present invention is to provide a suck back valve in which the pressure receiving surface of the diaphragm does not cause bubble accumulation.
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the invention described in claim 1 includes a flow path through which a liquid flows, a diaphragm for sucking back with a pressure receiving surface exposed to the flow path, and a reciprocating motion to displace the diaphragm. in the suck-back valve with an actuating member which, set in correspondence with the diaphragm in the middle of the flow path provided through in a straight line vignetting, site open to the flow path of the flow path inner diameter have a larger inside diameter, and the suck-back chamber having a protruding space protruding on both sides of the flow path around the flow path, the tilt of the bottom wall of the overhang space toward the flow path center of the imparting to said bottom wall and the spirit of the suck back valve, characterized in that it and a to form a semicircular I Tsurana on the side wall of the channel.
[0011]
According to the configuration of the invention described above, by reciprocating the operating body, the pressure receiving surface of the diaphragm exposed to the flow path is displaced, so that the liquid flowing through the flow path is sucked back. Here, since the suck back chamber provided in the middle of the flow path has an inner diameter larger than the inner diameter of the flow path, an overhanging space protruding from the flow path exists. Even if bubbles enter the overhanging space, it is desirable to make them easy to escape. For example, when the suck back valve is used in an inverted state, the pressure receiving surface of the diaphragm is located on the lower side, and the bottom wall of the overhanging space is located on the upper side. It is possible. In this invention, since the inclination toward the center of the flow path is given to the bottom wall of the suck back chamber, the bubbles are guided toward the center of the flow path along the inclination of the bottom wall of the overhanging space. As a result, bubbles can be easily removed.
[0012]
In order to achieve the above object, according to a second aspect of the present invention, in the first aspect of the present invention, the diaphragm is in a state in which the suck back chamber has a minimum volume when the operating body is located at the bottom dead center. Therefore, when the operating body is located at the top dead center, the suck back state with the suck back chamber as the maximum volume is entered, and the pressure receiving surface of the diaphragm in the suck back state is placed at the same level as the inner peripheral surface of the flow path. It is intended to be provided at a position that protrudes toward the center side of the flow path.
[0013]
According to the configuration of the invention, in addition to the action of the invention according to claim 1, when the diaphragm is in a suck-back state in which the suck-back chamber has the maximum volume, the pressure receiving surface is the same as the inner peripheral surface of the flow path. Since it is set at the same position or a position projecting toward the center of the flow path from that position, there is no formation of a concave space with respect to the flow path.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment embodying a suck back valve of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 shows a cross-sectional view of the upright suckback valve 1. FIG. 2 is a cross-sectional view taken along the line AA in FIG. The suck back valve 1 includes a valve body 3 and a cylinder 4. The valve body 3 is provided with a flow path 2 through which liquid flows.
[0016]
The valve body 3 is provided with a pair of ports 5 and 6 that communicate with the flow path 2. Each port 5 and 6 is provided with a pipe joint 7 and 8. The valve body 3 is provided with a diaphragm 9 that performs suck back by exposing the pressure receiving surface 9 a to the flow path 2. Corresponding to the diaphragm 9, the valve body 3 is provided with a suck back chamber 10. The suck back chamber 10 is provided in the middle of the flow path 2 corresponding to the diaphragm 9 and has an inner diameter D2 larger than the inner diameter D1 of the flow path 2. The suck back chamber 10 has an overhanging space 11 projecting on both sides of the flow path 2 as a center.
[0017]
A tubular guide washer 12 is provided between the valve body 3 and the cylinder 4. The outer peripheral portion 9 b of the diaphragm 9 is sandwiched and fixed between the flange 12 a of the guide washer 12 and the step portion 3 a of the valve body 3. FIG. 3 shows the sandwiched portion in detail in a cross-sectional view. A rigid body 13 made of, for example, metal or hard resin is embedded in the stepped portion 3 a of the valve body 3, and the outer peripheral portion 9 b of the diaphragm 9 is in close contact with the rigid body 13. Thereby, the adhesiveness of the radial direction of the diaphragm 9 is improved.
[0018]
A piston 15 as an operating body of the present invention is provided in the hollow portion 14 of the cylinder 4 so as to reciprocate along the axial direction. The piston 15 is slidably provided in the hollow portion 14 via a seal 16 attached to the outer periphery thereof. The piston rod 15a extending downward from the piston 15 is assembled so that the hollow portion 12b of the guide washer 12 can reciprocate along its axial direction. The piston rod 15a is slidably provided in the hollow portion 12b via a seal 17 mounted on the outer periphery thereof. A compression spring 18 is interposed between the flange 12 a of the guide washer 12 and the piston 15. The piston 15 is biased upward by the compression spring 18. A central projection 9c of the diaphragm 9 is coupled to the lower end of the piston rod 15a.
[0019]
The hollow portion 14 of the cylinder 4 is partitioned into two upper and lower chambers 14A and 14B by a piston 15. A working fluid is introduced into and led out from the upper working chamber 14 </ b> A through a working passage 19 provided in the cylinder 4. On the other hand, the atmosphere is introduced into the lower atmosphere chamber 14 </ b> B through the atmosphere passage 20 provided in the cylinder 4.
[0020]
Accordingly, when the working fluid is introduced into the working chamber 14A through the working passage 19, the piston 15 is pushed and moves downward, and the pressure receiving surface 9a of the diaphragm 9 is displaced downward together with the piston rod 15a. On the other hand, when the working fluid is led out from the working chamber 14A through the working passage 19, the piston 15 is pushed upward by the compression spring 18, and the pressure receiving surface 9a of the diaphragm 9 is displaced upward together with the piston rod 15a. In this way, the pressure receiving surface 9 a of the diaphragm 9 is displaced by the movement of the piston 15.
[0021]
An adjustment screw 21 is provided in the screw hole 4 a located on the axis of the cylinder 4. A seal 22 is attached to the flange 21a at the lower end of the adjustment screw 21, and the seal 22 ensures the hermeticity of the working chamber 14A. The lower end of the flange 21 a is provided so as to be able to contact the piston 15. The upper end portion of the adjustment screw 21 is provided through a cap nut 23 screwed into the upper portion of the cylinder 4. A knob 24 is fixed to the upper end of the adjustment screw 21.
[0022]
Therefore, the protrusion amount of the flange 21a with respect to the working chamber 14A is adjusted by screwing the adjustment screw 21 into the screw hole 4a by the operation of the knob 24 and moving it forward and backward. As a result, the stroke of the piston 15 and the displacement amount of the pressure receiving surface 9a of the diaphragm 9 are adjusted, and the suck back amount in the suck back chamber 10 is adjusted. Once the adjustment screw 21 has been adjusted, the adjustment screw 21 is fixed by tightening the cap nut 23.
[0023]
Here, the characteristic regarding the suck back chamber 10 is demonstrated in detail. FIG. 4 is a cross-sectional view showing only the portion of the suck back chamber 10 in the cross section along the line BB in FIG. As described above, the overhang space 11 of the sack back chamber 10 overhanging on both sides of the flow path 2 has the bottom wall 10a facing the pressure receiving surface 9a. These bottom walls 10 a are provided with an inclination of a predetermined angle θ <b> 1 toward the center of the flow path 2.
[0024]
In this embodiment, the arrangement of the diaphragm 9 in the suck back chamber 10 is set as follows. That is, the diaphragm 9 is in a state where the suck back chamber 10 has the minimum volume when the piston 15 is located at the bottom dead center, and the suck back where the suck back chamber 10 is the maximum volume when the piston 15 is located at the top dead center. It will be in the back state. 1 and 4 show the diaphragm 9 in a suck-back state. Here, the pressure receiving surface 9 a of the diaphragm 9 in the sucked back state is set at a position where it is placed on the same level as the inner peripheral surface of the flow path 2 and then protrudes to the center side of the flow path 2.
[0025]
As described above, according to the configuration of the suck back valve 1 of the present embodiment, the pressure receiving surface of the diaphragm 9 exposed to the flow path 2 by operating the piston 15 up and down in the upright state shown in FIG. 9a is displaced, the volume of the suck back chamber 10 is changed, and the suck back of the liquid flowing through the flow path 2 is performed.
[0026]
Here, since the suck-back chamber 10 provided in the middle of the flow path 2 has an inner diameter D2 larger than the inner diameter D1 of the flow path 2, there is an overhanging space 11 protruding from the flow path 2. Even if bubbles enter the overhanging space 11, it is desirable to make them easy to escape. For example, when the suck back valve 1 is used in an inverted state (a state rotated 180 degrees from the upright state in FIG. 1), the pressure receiving surface 9a of the diaphragm 9 is on the lower side, and the bottom wall 10a of the overhanging space 11 is placed. Are positioned on the upper side, and it is possible to improve the escape of bubbles using the bottom wall 10a. In the suck back valve 1 according to this embodiment, since the bottom wall 10a of the suck back chamber 10 is inclined toward the center of the flow path 2, the bottom wall 10a is in an inverted state as shown in FIG. Is inclined upward toward the flow path 2. Therefore, even if bubbles enter the suck back chamber 10, the bubbles are guided along the inclination of the bottom wall 10a toward the center of the flow path 2 as indicated by arrows in FIG. It becomes. For this reason, compared with the conventional suck back valve, the bubble removal from the periphery of the diaphragm 9 in the inverted state can be further improved, and the suck back chamber 10 can be prevented from becoming a bubble pool. it can.
[0027]
For this reason, the suction of the liquid can be stabilized during the suck back by the suck back valve 1, and the liquid flow rate can be adjusted accurately. Therefore, for example, even when the suck back valve 1 is provided and used between the chemical solution application nozzle and the chemical solution supply source, due to the presence of the overhanging space 11 in the sack back chamber 10, The adjustment of the application amount of the chemical solution does not become unstable.
[0028]
Further, in this embodiment, even when the diaphragm 9 is in a suck-back state in which the suck-back chamber 10 has the maximum volume, the pressure receiving surface 9a is placed at the same level as the inner peripheral surface of the flow path 2 and thereby the flow path 2 Therefore, a space that is recessed with respect to the inner peripheral surface of the flow path 2 is not formed. For this reason, it is possible to prevent the pressure receiving surface 9a of the diaphragm 9 disposed in the suck back chamber 10 from causing bubble accumulation in the state where the suck back valve 1 is disposed in the upright state. This also stabilizes the suction of the liquid during suck back and contributes to the accurate adjustment of the liquid flow rate.
[0029]
The present invention is not limited to the above-described embodiment, and a part of the configuration can be changed as appropriate without departing from the spirit of the invention.
[0030]
For example, in the above-described embodiment, the configuration related to the inclination of the bottom wall 10a of the suck back chamber 10 and the configuration related to the arrangement of the diaphragm 9 in the same chamber 10 are combined, but the configuration related to the latter arrangement may be omitted.
[0031]
In the above embodiment, the piston 15 as the operating body is reciprocated by the working fluid in order to displace the diaphragm 9. However, the operating body is reciprocated by an electric configuration to displace the diaphragm. For example, it can also be set as the structure reciprocated by the advance / retreat of the output shaft of a step motor.
[0032]
【Effect of the invention】
According to the configuration of the first aspect of the present invention, bubbles are guided toward the center of the flow path along the inclination of the bottom wall of the overhanging space of the suck-back chamber, and bubble removal is facilitated. For this reason, compared with the conventional suck back valve, the bubble removal from the periphery of the diaphragm in the inverted state can be further improved, and the suck back chamber can be prevented from becoming a bubble pool.
[0033]
According to the configuration of the invention described in claim 2, in addition to the effect of the invention described in claim 1, even when the diaphragm is in a suck-back state, a space that is recessed with respect to the inner peripheral surface of the flow path is formed. Not. For this reason, it is possible to prevent the pressure receiving surface of the diaphragm from causing bubble accumulation.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a suck back valve according to one embodiment.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a cross-sectional view showing a sandwiching portion of an outer peripheral portion of a diaphragm.
4 is a cross-sectional view showing a suck-back chamber portion in a cross section taken along line BB in FIG. 1. FIG.
FIG. 5 is an enlarged sectional view showing a suck back chamber in an inverted state.
FIG. 6 is a longitudinal sectional view showing a conventional suck back valve.
FIG. 7 is a longitudinal sectional view showing a conventional suck back valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Suck back valve 2 Flow path 9 Diaphragm 9a Pressure receiving surface 10 Suck back chamber 10a Bottom wall 11 Overhang space 15 Piston (operating body)
θ1 Predetermined angle D1 Inner diameter D2 Inner diameter

Claims (2)

A flow path through which liquid flows;
A diaphragm that exposes the pressure receiving surface to the flow path and performs a suck back; and
In a suck back valve comprising an actuating element that reciprocates to displace the diaphragm,
A portion that is provided corresponding to the diaphragm in the middle of the flow path that penetrates in a straight line has an inner diameter that is larger than the inner diameter of the flow path, and that is centered on the flow path. A sackback chamber having a protruding space protruding on both sides of the flow path;
The bottom wall of the overhanging space is inclined toward the center of the flow path and away from the operating body , and the bottom wall is connected to the side wall of the flow path between the bottom walls. A suck-back valve comprising: an inner peripheral surface of a flow path having a semicircular shape. The diaphragm is in a state in which the suck back chamber has a minimum volume when the operating body is located at a bottom dead center, and the suck back chamber has a maximum volume when the operating body is located at a top dead center. Going into a suckback state,
The pressure-receiving surface of the diaphragm in the suck-back state is set at the same position as the inner peripheral surface of the flow path, and then protrudes to the center side of the flow path;
The suck back valve according to claim 1, further comprising:

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