Diaphragm pump

Abstract

A diaphragm pump (1) for sucking and discharging a resist liquid supplied to a semiconductor wafer by a predetermined amount is provided with a diaphragm (20), a body (10), a detected part (3), and a detection part (4). The diaphragm (20) is formed by forming a film-like resin. The body (10) has a space part (13) in which the diaphragm (20) is disposed so as to be displaceable, and the space part (13) is partitioned into a chemical liquid chamber (14) and a drive chamber (15). The detected part (3) is held by the body (10) so as to be able to come into contact with a surface positioned on the side of the drive chamber (15) of the diaphragm (20), and can move following the diaphragm (20). The detection part (4) detects the displacement of the diaphragm (20) on the basis of the position of the detected part (3).

Description

diaphragm pump

[0001] The present invention relates to a diaphragm pump installed in a chemical liquid supply line of a semiconductor manufacturing device.

[0002] Diaphragm pumps are installed in chemical supply lines in semiconductor manufacturing equipment and are used to control the supply of chemicals to semiconductor wafers. A diaphragm divides a space formed inside a body into a chemical chamber and a drive chamber. The diaphragm is displaceable and alternately displaces toward the chemical chamber and the drive chamber by varying the pressure inside the drive chamber between positive and negative pressures, thereby drawing in and discharging the chemical. The diaphragm pump is equipped with a magnet and a magnet position sensor for detecting the displacement of the diaphragm. A connecting portion protrudes from the membrane portion at the center of the diaphragm on the drive chamber side. A magnet is fixed to the connecting portion with a screw, and a magnet position sensor is installed on the body side. The discharge rate of the chemical can be controlled to a predetermined amount by detecting the diaphragm position based on the position of the magnet (see, for example, Patent Document 1).

[0003] Furthermore, in order to suppress particle generation from the surface of the diaphragm, the diaphragm pump uses PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin) as the diaphragm material, and the surface is smoothed by extrusion molding (see, for example, Patent Document 2).

[0004] JP 2006-46284 A Japanese Patent No. 6602553 A

[0005] The diaphragm of a diaphragm pump alternates between expanding from a neutral position toward the drive chamber (suction) and expanding from a neutral position toward the chemical chamber (discharge).When the diaphragm displaces, stress concentrates near the boundary between the connecting part and the membrane part, causing it to deteriorate easily.

[0006] Furthermore, even if a diaphragm is made of a material that is less likely to generate particles, there is a risk of particles being generated from areas that have deteriorated due to stress concentration. In recent years, semiconductor circuits have become increasingly miniaturized, and even minute particles less than 20 nm in size that cannot be measured by particle measurement devices can affect semiconductor yields. Therefore, in diaphragm pumps used in semiconductor manufacturing, it is desirable to eliminate particle generation causes as much as possible and suppress particle generation.

[0007] One aspect of a diaphragm pump made to solve the above problems is (1) a diaphragm pump that sucks in and discharges a predetermined amount of chemical liquid to be supplied to a semiconductor wafer, and has a membrane-like diaphragm formed from resin, and a space in which the diaphragm is displaceably arranged, the space being partitioned by the diaphragm into a chemical liquid chamber into which the chemical liquid flows and a drive chamber into which an operating fluid that displaces the diaphragm is supplied, a detectable part that is held by the body so as to be able to come into contact with the surface of the diaphragm located on the drive chamber side and is capable of moving in accordance with the diaphragm, and a detection part that detects the displacement of the diaphragm based on the position of the detectable part.

[0008] In a diaphragm pump having the above configuration, the position of the diaphragm is detected based on the position of the detected part, which moves in accordance with the diaphragm. When the detected part moves in accordance with the diaphragm, the film-like diaphragm can freely deform relative to the detected part because the detected part and the diaphragm are only in contact with each other. As a result, the diaphragm is less susceptible to deterioration due to stress concentration, and particle generation is suppressed. Therefore, with a diaphragm pump having the above configuration, it is possible to improve the durability of the diaphragm and suppress particle generation in a diaphragm pump having a function for detecting diaphragm displacement.

[0009] (2) In the diaphragm pump described in (1), it is preferable that the diaphragm is formed by extrusion molding, roll molding, or both the extrusion molding and the roll molding.

[0010] In a diaphragm pump having the above configuration, the surface of the diaphragm is not machined, so there are no irregularities on the surface of the diaphragm due to machining marks, and the generation of particles due to the irregularities on the diaphragm is therefore suppressed.

[0011] (3) In the diaphragm pump described in (1) or (2), it is preferable that the material of the diaphragm is PFA.

[0012] In a diaphragm pump having the above configuration, a diaphragm made from PFA reduces the generation of particles at the liquid contact surface compared to a diaphragm made from compression-molded PTFE, so by using a diaphragm made from PFA, it is possible to reduce the generation of particles that affect semiconductor manufacturing.

[0013] (4) In the diaphragm pump according to any one of (1) to (3), it is preferable that the movable distance of the detection target part is smaller than the maximum stroke amount of the diaphragm.

[0014] In the diaphragm pump having the above configuration, the detected part follows the diaphragm for part of the diaphragm's stroke and does not follow the diaphragm for the remaining stroke, so the diaphragm is less likely to rub against the moving part and wear out, improving the durability of the diaphragm.

[0015] (5) In the diaphragm pump described in any one of (1) to (4), it is preferable that the diaphragm has a membrane thickness of 0.1 mm or more and 0.3 mm or less.

[0016] In the diaphragm pump with the above configuration, the diaphragm has a thin thickness of 0.1 mm to 0.3 mm, so the tension when the diaphragm displaces is small and the diaphragm easily deforms in response to fluctuations in the internal pressure of the drive chamber. Therefore, the diaphragm pump with the above configuration can be expected to have good discharge performance. Furthermore, because the diaphragm is thin and is less likely to deteriorate due to stress concentration during deformation, particle generation can be suppressed.

[0017] (6) In the diaphragm pump described in (5), it is preferable that a biasing member be provided to bias the detected portion toward the space portion, and the biasing force of the biasing member be 0.05 N or more and 0.15 N or less.

[0018] In the diaphragm pump of the above configuration, the biasing force of the biasing member that biases the detected portion toward the space portion is a load that is not significantly greater than the tension of the thin diaphragm, so the diaphragm can easily deform freely relative to the detected portion.

[0019] (7) In the diaphragm pump described in any one of (1) to (6), it is preferable that the diaphragm is arranged in the body in a state where the portion corresponding to the space portion is bent when the diaphragm is in an unloaded state.

[0020] In a diaphragm pump with the above configuration, tension does not act on the diaphragm when it is displaced, so pressure loss is unlikely to occur when the diaphragm is displaced, and the discharge rate of the chemical liquid is stable. Furthermore, in a diaphragm pump, stress concentration is unlikely to occur on the displacing diaphragm, making the diaphragm less likely to be damaged.

[0021] (8) In the diaphragm pump described in any one of (1) to (7), it is preferable that the body has a bottomed retaining hole that opens to the inner wall of the drive chamber, the retaining hole accommodates the detectable part and a biasing member that biases the detectable part toward the space part, and the detection part is arranged outside the retaining hole.

[0022] In the diaphragm pump of the above configuration, the detected part and the detecting part are arranged with the drive chamber kept airtight, so there is no leakage of operating fluid from the detected part and the detecting part is not corroded by chemical liquid that has permeated the diaphragm.

[0023] (9) In the diaphragm pump described in (8), it is preferable that the detected part has a magnet that is detected by the detection part, a movable part to which the magnet is attached and that is housed in the retaining hole so that it can protrude or retract, and a stopper part that is arranged inside the retaining hole and limits the movement of the movable part.

[0024] In the diaphragm pump having the above configuration, particles generated from the detected portion can be suppressed, and the detected portion can be movably disposed in the body in a compact structure independent from the diaphragm.

[0025] According to the technology disclosed in this specification, in a diaphragm pump having a function of detecting displacement of a diaphragm, it is possible to improve the durability of the diaphragm and suppress the generation of particles.

[0026] Fig. 5 is a cross-sectional view of a diaphragm pump showing an unloaded state; Fig. 6 is a cross-sectional view of a diaphragm pump showing a discharge completion state; Fig. 7 is a cross-sectional view of a diaphragm pump showing a suction completion state; Fig. 8 is an enlarged view of a portion A1 in Fig. 1; Fig. 9 is an enlarged view of a portion A2 in Fig. 2; Fig. 10 is an enlarged view of a detected portion; Fig. 11 is an enlarged view of a portion A3 in Fig. 5; Fig. 12 is a cross-sectional view showing a modified example of a diaphragm pump; Fig. 13 is a cross-sectional view of a diaphragm pump showing a discharge completion state; Fig. 14 is a cross-sectional view of a diaphragm pump showing a discharge completion state; Fig. 15 is a cross-sectional view of a diaphragm pump showing a discharge completion state; Fig. 16 is a cross-sectional view of a portion A2 in Fig. 2; Fig. 17 is an enlarged view of a detected portion; Fig. 18 is an enlarged view of a portion A3 in Fig. 5; Fig. 19 is a cross-sectional view showing a modified example of a diaphragm pump;

[0027] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings. This specification discloses a diaphragm pump that is incorporated into a semiconductor manufacturing device and used to supply a resist solution.

[0028] The diaphragm pump 1 shown in Figures 1 to 3 is disposed in a chemical liquid supply line of a semiconductor manufacturing device and is used to control the supply of chemical liquid to be supplied to a semiconductor wafer (not shown). The diaphragm pump 1 of this embodiment controls a resist liquid as an example of a chemical liquid. The drive chamber 15 of the diaphragm pump 1 is alternately placed in a positive pressure state and a negative pressure state, so that the diaphragm 20 shown in Figure 1 is displaced toward the chemical liquid chamber 14 and the drive chamber 15 as shown in Figures 2 and 3, thereby discharging and sucking a predetermined amount of resist liquid.

[0029] As shown in FIG. 1, the diaphragm pump 1 includes a body 10, a diaphragm 20, a detected part 3, and a detecting part 4.

[0030] The body 10 includes a first housing 11 and a second housing 12 connected via a diaphragm 20. The first housing 11 and the second housing 12 are made of a highly corrosion-resistant fluororesin. In this embodiment, the first housing 11 and the second housing 12 are made of PFA.

[0031] First and second housings 11 and 12 have a first concave surface 111 and a second concave surface 121 formed in a generally dome shape on their contacting surfaces. Body 10 has first and second concave surfaces 111 and 121 that define a space 13 between first and second housings 11 and 12. A diaphragm 20 is displaceably disposed in space 13. Diaphragm 20 is membrane-shaped, and its outer edge is sandwiched between first and second housings 11 and 12, thereby airtightly dividing space 13 into a chemical solution chamber 14 and a drive chamber 15.

[0032] The first housing 11 is formed with an inlet flow path 16 and an outlet flow path 17 opening to the first recessed surface 111, thereby forming flow paths for flowing the resist solution in and out of the chemical chamber 14. The second housing 12 is formed with an operation flow path (not shown) opening to the second recessed surface 121, thereby forming a flow path for supplying and exhausting operation air to and from the drive chamber 15. The operation air is an example of an "operation fluid."

[0033] The diaphragm 20 is formed from a resin that is easy to mold. The raw material for the diaphragm 20 is preferably a corrosion-resistant fluororesin. More preferably, the raw material for the diaphragm 20 is PFA. The inventors conducted tests in which a fixed amount of fluid was supplied to a diaphragm pump 1 incorporating a PFA diaphragm 20 and a diaphragm pump incorporating a compression-molded PTFE (polytetrafluoroethylene) diaphragm, and the number of particles contained in the fixed amount of fluid was counted using a particle counter, and the results confirmed that the PFA diaphragm generated fewer particles than the PTFE diaphragm.

[0034] The raw material of the diaphragm 20 may be a fluororesin other than PFA, such as PP (polypropylene), PVDF (polyvinylidene fluoride), or PVDC (polyvinylidene chloride). Diaphragms made from these fluororesins are also expected to be more effective at suppressing particles than PTFE diaphragms. Furthermore, diaphragms made from these fluororesins are expected to be more effective at suppressing particle generation when molded by extrusion molding, roll molding, or both.

[0035] The diaphragm 20 is formed in the shape of a thin film. The thickness of the diaphragm 20 is preferably 0.1 mm or more and 0.3 mm or less. If the thickness of the diaphragm 20 is less than 0.1 mm, there is a possibility that the diaphragm 20 may be torn when it comes into contact with and rubs against the detected part 3. On the other hand, if the thickness of the diaphragm 20 is more than 0.3 mm, there is a possibility that the tension acting on the diaphragm 20 will increase, which may reduce the pump discharge performance or generate particles due to stress concentration.

[0036] The diaphragm 20 is molded so that the portion disposed in the space 13 bends to one side. As shown in Figure 4, when the diaphragm 20 is assembled to the body 10 in an unloaded state, the detected portion 3 is positioned at a predetermined distance L1 from the diaphragm 20, so that tension is not applied to the diaphragm 20. In particular, by molding the diaphragm 20 to bend toward the chemical solution chamber 14, the range over which the diaphragm 20 separates from the detected portion 3 and displaces is widened, thereby suppressing wear of the diaphragm 20. The position of the diaphragm 20 in an unloaded state is referred to as the "neutral position P1."

[0037] The diaphragm 20 of this embodiment is formed into the shape shown in Fig. 1 by extrusion molding, and then the surface is smoothed by roll molding in order to prevent particles from being generated on the surface of the diaphragm 20.

[0038] The body 10 has a cylindrical retaining hole 122 formed in the center of the second concave surface 121. The detected part 3 is provided separately from the diaphragm 20 and is movably housed in the retaining hole 122. The detected part 3 is held by the body 10 so as to be able to come into contact with the surface of the diaphragm 20 that is positioned on the drive chamber 15 side, and can move in conjunction with the diaphragm 20.

[0039] The configuration of the detected part 3 will be specifically described with reference to Figures 4 to 7. Figure 4 is an enlarged view of part A1 in Figure 1. Figure 5 is an enlarged view of part A2 in Figure 2. Figure 6 is an enlarged view corresponding to Figure 4, showing the state in which the diaphragm 20 abuts against the detected part 3. Figure 7 is an enlarged view of part A3 in Figure 3.

[0040] 4 to 7, the detected part 3 is composed of a pump screw 32, a magnet 33, and a plunger 34, and the magnet 33 is sandwiched between the pump screw 32 and the plunger 34. The pump screw 32 and the plunger 34 are examples of a "moving part."

[0041] The detected part 3 is held in the holding hole 122 by a guide member 38 and a bush 39 so as to be movable along the displacement direction (left-right direction in the figure) of the diaphragm 20. The detected part 3 is constantly biased by a spring 36 in a direction that causes it to protrude from the holding hole 122.

[0042] As shown in Figure 4, the magnet 33 has a cylindrical shape with a hollow hole 331. The pump screw 32 has a leg 321 on one end of which a male thread portion 321a is formed, and a head 322 is provided. The outer diameter of the head 322 is approximately the same as the outer diameter of the outer peripheral surface 332 of the magnet 33. The plunger 34 has a substantially cylindrical shape, and a female threaded hole 341, into which the male thread portion 321a is fastened, is opened on a surface 345 opposite a contact surface 343 that contacts the diaphragm 20.

[0043] The detected part 3 holds the magnet 33 in a state where axial movement between the plunger 34 and the head 322 of the pump screw 32 is restricted by threading the leg 321 of the pump screw 32, which is inserted into the hollow hole 331 of the magnet 33, onto the plunger 34. The plunger 34 has a stepped portion 342 formed in an annular shape along the outer periphery of the opening of the female threaded hole 341. The stepped portion 342 and the leg 321 of the pump screw 32 suppress radial wobble of the magnet 33.

[0044] The amount of movement of the detected part 3 is restricted by a guide member 38. The guide member 38 is cup-shaped with an opening 381 that opens on one side, and an insertion hole 383 is formed in a closed surface 382. The guide member 38 is fitted into the holding hole 122 with the open end abutting against the bottom surface of the holding hole 122.

[0045] The head 322 of the pump screw 32 has a flange 323 that protrudes radially outward along the outer periphery of the end face located opposite the leg 321. The inner diameter of the insertion hole 383 is larger than the outer diameter of the head 322 and smaller than the outer diameter of the flange 323. The detected part 3 is attached to the guide member 38 from the opening 381 side so that the flange 323 can abut against the closing surface 382.

[0046] The spring 36 is compressed between the head 322 of the pump screw 32 and the bottom surface of the retaining hole 122, and constantly applies a biasing force to the detected part 3 in a direction that causes it to protrude from the retaining hole 122 into the drive chamber 15. The spring 36 is an example of a "biasing member." The detected part 3 has its flange 323 engaged with the closing surface 382, ​​so that its movement in the protruding direction from the retaining hole 122 into the drive chamber 15 is limited. In other words, the maximum protrusion amount of the detected part 3 into the drive chamber 15 is defined. The position of the detected part 3 in this case is referred to as the "off position P11."

[0047] 7 , the movement of the detected part 3 in the retraction direction from the drive chamber 15 to the retaining hole 122 is restricted by the engagement of the flange 323 with the bottom surface of the retaining hole 122. In other words, the minimum amount of protrusion of the detected part 3 into the drive chamber 15 is defined. The position of the detected part 3 in this case is referred to as the "ON position P12." In this embodiment, the flange 323, the closing surface 382, ​​and the bottom surface of the retaining hole 122 constitute an example of a "stopper part."

[0048] The detected part 3 has a flat contact surface 343 of the plunger 34 that comes into contact with the diaphragm 20, and corners 344 of the contact surface 343 are rounded to form a smooth curved surface. This reduces the frictional resistance that occurs between the detected part 3 and the diaphragm 20.

[0049] The distance L3 over which the detected part 3 moves from the OFF position P11 to the ON position P12 is set to be smaller than the maximum stroke amount L4 of the diaphragm 20. The maximum stroke amount L4 is the distance between the discharge completion position P2 where the diaphragm 20 deforms along the first concave surface 111 and the full stroke position P4 where the diaphragm 20 deforms along the second concave surface 121. The detected part 3 comes into contact with the diaphragm 20 during part of the stroke of the diaphragm 20 as shown in Figures 6 and 7, and does not come into contact with the diaphragm 20 during the remaining part of the stroke of the diaphragm 20 as shown in Figures 4 to 6, thereby reducing the area over which the diaphragm 20 comes into contact with the detected part 3 and suppressing wear on the diaphragm 20.

[0050] The movement distance L3 is preferably 50% or less of the maximum stroke amount L4. This is to reduce the range of displacement of the diaphragm 20 when it is in contact with the detected part 3, thereby suppressing wear of the diaphragm 20. More preferably, the movement distance L3 is 30% or less of the maximum stroke amount L4. This is because the diaphragm 20 comes into contact with the detected part 3 just before reaching the full stroke position P4, thereby reducing the load that the diaphragm 20 receives from the detected part 3 and improving the durability of the diaphragm 20.

[0051] The diaphragm pump 1 discharges and sucks the resist liquid by creating positive and negative pressure states in the drive chamber 15. Therefore, the spring 36 is arranged not for the purpose of displacing the diaphragm 20, but for the purpose of returning the detected part 3 from the ON position P12 to the OFF position P11. Therefore, the biasing force of the spring 36 is set to a level that applies to the diaphragm 20 a load that is not significantly greater than the tension of the diaphragm 20. In this embodiment, the diaphragm 20 is thin, with a film thickness of 0.1 mm to 0.3 mm, and has a small tension, so the biasing force of the spring 36 is set to a level that is 0.05 N to 0.15 N.

[0052] The bushing 39 is press-fitted into the retaining hole 122 until it abuts against the guide member 38, and positions and holds the guide member 38, on which the biasing force of the spring 36 acts, within the retaining hole 122. Because the guide member 38 and the bushing 39 are press-fitted into the retaining hole 122, the detected part 3 can be attached to the retaining hole 122 without twisting the spring 36. The bushing 39 is disposed between the inner circumferential surface of the retaining hole 122 and the outer circumferential surface of the plunger 34, and holds the plunger 34 slidably.

[0053] The pump screw 32, plunger 34, guide member 38, and bushing 39 are made of fluororesin. They are preferably formed by a processing method other than cutting, such as extrusion molding or injection molding. This is to prevent particles from being generated from cutting marks and to enable the detected part 3 to move with good responsiveness in response to the displacement of the diaphragm 20.

[0054] 1 , the detection unit 4 is a magnetic sensor that detects the position of the detected part 3. The detection unit 4 is disposed outside the holding hole 122 and detects the displacement of the diaphragm 20 based on the position of the detected part 3. The detection unit 4 is connected to a host controller (not shown) that manages the process performed on the semiconductor wafer. When the detected part 3 is disposed in the ON position P12, the detection unit 4 transmits a detection signal to the host controller (not shown), and when the detected part 3 is not disposed in the ON position P12, the detection unit 4 does not transmit a detection signal to the host controller (not shown).

[0055] Next, we will explain the operation of diaphragm pump 1. In diaphragm pump 1 shown in Figure 1, when operating air is supplied to drive chamber 15 and positive pressure is created, diaphragm 20 deforms to fit first concave surface 111 and is positioned at discharge completion position P2, as shown in Figure 2. This minimizes the volume of chemical solution chamber 14.

[0056] As shown in Figure 5, when the diaphragm 20 is positioned at the discharge completion position P2, the flange portion 323 of the pump screw 32 is engaged with the closing surface 382 of the guide member 38, and the detected part 3 is positioned at the off position P11.

[0057] The diaphragm 20 is disposed at the discharge completion position P2, away from the detected portion 3, which is disposed at the off position P11. Moreover, the diaphragm 20 is attached to the body 10 in a state in which it is bent toward the first concave surface 111 when in an unloaded state. Therefore, the tension acting on the diaphragm 20 at the discharge completion position P2 is smaller than that of a diaphragm attached to the body 10 in a flat state when in an unloaded state.

[0058] 2 does not detect the magnet 33 of the detected part 3 in the OFF position P11, and therefore the detector 4 does not transmit a detection signal to a higher-level controller (not shown).

[0059] In the diaphragm pump 1 shown in Figure 2, when operating air is exhausted from the drive chamber 15 and the internal pressure of the drive chamber 15 decreases, the diaphragm 20 deforms toward the second concave surface 121 (the drive chamber 15 side) due to its own elastic force, and the sealing force of the diaphragm 20 against the first concave surface 111 decreases.

[0060] 5, the first concave surface 111 has a plurality of grooves 112 formed in the circumferential direction and a plurality of grooves 113 formed in the radial direction. Therefore, when the sealing force decreases, the resist liquid that has entered the inlet flow path 16 passes through the grooves 112 and 113 and begins to flow toward the outlet flow path 17. As a result, a force acts on the diaphragm 20 in a direction away from the first concave surface 111 (toward the second concave surface 121).

[0061] In this way, when the operating air begins to be exhausted from the drive chamber 15 of the diaphragm pump 1, the diaphragm 20 responsively moves away from the first concave surface 111 due to its own elastic force and the pressure of the resist liquid, and is displaced toward the second concave surface 121 (the drive chamber 15 side).

[0062] 6, the diaphragm 20 displaces from the discharge completion position P2 to a contact position P3 where it contacts the contact surface 343 of the detected part 3 while being separated from the detected part 3. Therefore, while the diaphragm 20 displaces from the discharge completion position P2 to the contact position P3, the detected part 3 does not move following the diaphragm 20, but is positioned at the off position P11.

[0063] When the diaphragm 20 deforms so as to bulge from the abutment position P3 toward the second concave surface 121 (toward the drive chamber 15), it presses the contact surface 343 of the detected part 3 toward the retaining hole 122. The biasing force of the spring 36 that biases the detected part 3 is small, at 0.05 N or more and 0.15 N or less. Therefore, the detected part 3 can move in the retraction direction following the diaphragm 20 without impairing the displacement of the diaphragm 20.

[0064] 3, in the diaphragm pump 1, the diaphragm 20 is displaced to a full stroke position P4 where it deforms along the second concave surface 121. As the diaphragm 20 deforms to bulge toward the second concave surface 121, the resist liquid flows into the chemical chamber 14. When the diaphragm 20 is displaced to the full stroke position P4, the volume of the chemical chamber 14 becomes maximum.

[0065] 7, the head 322 of the pump screw 32 hits the bottom surface of the retaining hole 122, restricting movement of the detected part 3 in the retracting direction and positioning it at the ON position P12. At this time, the plunger 34 of the detected part 3 protrudes slightly toward the drive chamber 15. Therefore, the detected part 3 is pushed into the retaining hole 122 by the diaphragm 20, which is positioned at the full stroke position P4, and is stably positioned at the ON position P12.

[0066] The detected part 3 has a flat contact surface 343 with smoothly curved corners 344. Therefore, the diaphragm 20, which is positioned at the full stroke position P4, deforms gently between the contact surface 343 and the second concave surface 121, making it less likely that deterioration due to stress concentration will occur in the part that contacts the detected part 3. This makes it possible to prevent particles from being generated from the deteriorated part due to stress concentration.

[0067] 3 detects the magnet 33 when the detected part 3 is placed in the ON position P12, and transmits a detection signal to a higher-level controller (not shown). Based on the detection signal, the higher-level controller (not shown) detects that the diaphragm pump 1 has sucked up a predetermined amount of resist liquid.

[0068] In the diaphragm pump 1 shown in Fig. 3, when the drive chamber 15 is supplied with operating air and placed in a positive pressure state, the diaphragm 20 is displaced to the discharge completion position P2 as shown in Fig. 2. By forming the diaphragm 20 to bulge toward the first concave surface 111, a predetermined amount of resist liquid that has flowed into the chemical liquid chamber 14 is discharged from the outflow channel 17.

[0069] 6, when the diaphragm 20 begins to displace toward the first concave surface 111 (toward the chemical solution chamber 14), the detected part 3 is biased by the spring 36 and moves in the protruding direction. In other words, the detected part 3 can move in conjunction with the diaphragm 20.

[0070] The detected part 3 and the diaphragm 20 are separate bodies, and the detected part 3 is only in contact with the diaphragm 20. Therefore, when the detected part 3 moves following the diaphragm 20, the diaphragm 20 can deform freely relative to the detected part 3, and the tension acting on the part in contact with the detected part 3 is small.

[0071] Moreover, the biasing force of the spring 36 is small, at 0.05 N or more and 0.15 N or less. Therefore, a small load acts on the portion of the detected part 3 that contacts the diaphragm 20. Therefore, even if the detected part 3 contacts the diaphragm 20 and moves following the diaphragm 20, the portion of the diaphragm 20 that contacts the detected part 3 is less likely to wear out and is less likely to generate particles.

[0072] 5, the detected part 3 cannot move in the protruding direction beyond the OFF position P11 because the flange 323 of the pump screw 32 is locked by the closing surface 382 of the guide member 38. Therefore, the diaphragm 20 is displaced separately from the detected part 3 while displacing from the abutting position P3 to the discharge completion position P2, and therefore is not subjected to any load other than that of the operating air, and is less likely to deteriorate due to stress concentration.

[0073] 2, when the detected part 3 moves from the ON position P12 to the OFF position P11, the detecting part 4 can no longer detect the magnet 33 and therefore no longer transmits a detection signal to a higher-level controller (not shown). When the higher-level controller (not shown) no longer receives the detection signal, it detects that the diaphragm pump 1 has supplied a predetermined amount of resist liquid to a semiconductor wafer (not shown).

[0074] In the diaphragm pump 1, the discharge completion position P2 and the full stroke position P4 of the diaphragm 20 are determined by the first concave surface 111 and the second concave surface 121, so that the maximum and minimum volumes of the chemical liquid chamber 14 are stable. Therefore, even if the diaphragm pump 1 repeats discharge and suction, it can accurately supply a predetermined amount of resist liquid to a semiconductor wafer (not shown).

[0075] The diaphragm 20 is attached to the body 10 in a state where the portion corresponding to the space 13 is bent toward the first concave surface 111 under no load, so no tension is applied when the diaphragm 20 is displaced. Therefore, the diaphragm pump 1 is less likely to experience pressure loss when the diaphragm 20 is displaced, and the discharge amount of the resist liquid is stable.

[0076] The diaphragm 20 is thin and the tension acting on the diaphragm 20 is small, so it is easily deformed in response to pressure fluctuations in the drive chamber 15. Therefore, good discharge performance can be expected from the diaphragm pump 1. Furthermore, even if the diaphragm 20 is repeatedly deformed, it is less likely to deteriorate due to stress concentration, and particle generation can be suppressed.

[0077] The diaphragm 20 is made from PFA, which is less likely to generate particles. The diaphragm 20 is formed by extrusion molding and roll molding, and is free of unevenness due to cutting marks, making it less likely to generate particles. Therefore, even if the diaphragm 20 is repeatedly deformed, particles are less likely to be generated from its surface.

[0078] Furthermore, the diaphragm 20 is provided separately from the detected part 3 and can be displaced separately from the detected part 3, so no load other than the operating air acts on the diaphragm 20. Therefore, the tension acting on the diaphragm 20 is small, the diaphragm 20 is less likely to deteriorate due to stress concentration, and particles are less likely to be generated from deteriorated parts.

[0079] 5 to 7, in the diaphragm pump 1, the detected portion 3 moves in contact with the diaphragm 20 for part of the stroke of the diaphragm 20. Therefore, in the diaphragm pump 1, the diaphragm 20 is less likely to rub against the detected portion 3 and wear out, and the durability of the diaphragm 20 is improved, compared to when the detected portion is in contact with the diaphragm for the entire stroke of the diaphragm.

[0080] Even if the diaphragm 20 rubs against the detected part 3 and wears out, generating particles, the particles are contained in the driving chamber 15 and do not get mixed into the resist liquid, since the detected part 3 is provided on the driving chamber 15 side.

[0081] In the diaphragm pump 1, the detected part 3 is disposed inside the holding hole 122, and the detecting part 4 that detects the detected part 3 is provided outside the holding hole 122. In other words, in the diaphragm pump 1, the detected part 3 and the detecting part 4 are disposed in a state in which the drive chamber 15 is kept airtight. Therefore, there is no leakage of operating air from the detected part 3, and the detecting part 4 is not corroded by the resist liquid that has permeated the diaphragm 20.

[0082] Furthermore, in the diaphragm pump 1, the detection part 3 is slidably disposed in the retaining hole 122, and the flange 323 of the pump screw 32 is brought into contact with the closing surface 382 of the guide member 38 and the bottom surface of the retaining hole 122, thereby restricting the movement range of the detection part 3, thereby suppressing particles generated from the detection part 3. Furthermore, the diaphragm pump 1 has a compact structure, and the detection part 3 can be movably disposed in the body 10 while being independent from the diaphragm 20.

[0083] As described above, in the diaphragm pump 1 of this embodiment, the position of the diaphragm 20 is detected based on the position of the detected part 3, which moves in accordance with the diaphragm 20. When the detected part 3 moves in accordance with the diaphragm 20, the film-like diaphragm 20 can freely deform relative to the detected part 3 because the detected part 3 and the diaphragm 20 are only in contact with each other. As a result, the diaphragm 20 is less susceptible to deterioration due to stress concentration, and particle generation is suppressed. Therefore, according to the diaphragm pump 1 of this embodiment, in a diaphragm pump 1 having a function of detecting the displacement of the diaphragm 20, the durability of the diaphragm 20 can be improved and particle generation can be suppressed.

[0084] The present invention is not limited to the above-described embodiment and can be applied in various ways. For example, the contact surface 343 of the detected part 3 does not have to be a flat surface, but may be a gently convex or concave surface.

[0085] For example, the diaphragm 20 may be formed by either extrusion molding or roll molding. Alternatively, the diaphragm 20 may be formed by injection molding. Furthermore, the diaphragm 20 may be formed by extruding a molten plasticized resin in an extruder into a thin film tube through a tube forming die, and then cutting the thin film tubular extrusion into a sheet.

[0086] For example, the film thickness of the diaphragm 20 does not have to be 0.1 mm or more and 0.3 mm or less. However, a thin diaphragm 20 having a film thickness of 0.1 mm or more and 0.3 mm or less can be expected to be more effective in suppressing particle generation by being formed by extrusion molding, roll molding, or both.

[0087] If the diaphragm 20 and the detected part 3 are separate and separable, the movement distance L3 of the detected part 3 may be the same as the maximum stroke amount L4 of the diaphragm 20. However, by making the movement distance L3 smaller than the maximum stroke amount L4, it is possible to prevent the diaphragm 20 from moving away from the detected part 3 and rubbing against the detected part 3, thereby preventing wear.

[0088] For example, as shown in FIG. 8, the diaphragm 20 may be disposed in the space 13 in a flat state when no load is applied.

[0089] For example, the diaphragm 20 may be formed in a flat sheet shape. However, by forming the portion of the diaphragm 20 that is to be placed in the space 13 in a curved shape, the diaphragm 20 can be easily placed in the body 10 with the portion corresponding to the space 13 bent in an unloaded state.

[0090] For example, the detection unit 4 may be arranged so as to communicate with the holding hole 122 .

[0091] For example, the pump screw 32 may be divided into a first part that is engaged with the guide member 38 and a second part that has a male thread portion 321 a that is fastened to the female threaded hole 341 of the plunger 34 .

[0092] For example, the movable portion may be formed as a single component, and the magnet 33 may be assembled to the movable portion by insert molding.

[0093] REFERENCE SIGNS LIST 1 diaphragm pump 3 detected part 4 detection part 10 body 20 diaphragm

Claims

1. A diaphragm pump which draws in and discharges a predetermined amount of chemical liquid to be supplied to a semiconductor wafer, comprising: a membrane-like diaphragm formed from resin; a body having a space in which the diaphragm is displaceably disposed, the space being partitioned by the diaphragm into a chemical liquid chamber into which the chemical liquid flows and a drive chamber into which an operating fluid that displaces the diaphragm is supplied; a detectable part which is held by the body so as to be able to come into contact with a surface of the diaphragm located on the drive chamber side and which can move in accordance with the diaphragm; and a detection part which detects the displacement of the diaphragm based on the position of the detectable part.

2. A diaphragm pump as described in claim 1, wherein the diaphragm is formed by extrusion molding, roll molding, or both of the extrusion molding and the roll molding.

3. A diaphragm pump as set forth in claim 1 or 2, wherein the material of the diaphragm is PFA.

4. A diaphragm pump as claimed in claim 1 or 2, wherein the distance that the detected part can move is shorter than the maximum stroke amount of the diaphragm.

5. A diaphragm pump as set forth in claim 1 or 2, wherein the diaphragm has a film thickness of 0.1 mm or more and 0.3 mm or less.

6. A diaphragm pump as described in claim 5, further comprising a biasing member for biasing the detected portion toward the space, the biasing force of the biasing member being 0.05N or more and 0.15N or less.

7. A diaphragm pump as claimed in claim 1 or 2, wherein the diaphragm is arranged in the body with the portion of the diaphragm corresponding to the space being deflected when the diaphragm is in an unloaded state.

8. A diaphragm pump as claimed in claim 1 or 2, wherein the body has a bottomed retaining hole that opens into the inner wall of the drive chamber, the retaining hole contains the detectable part and a biasing member that biases the detectable part towards the space, and the detection part is arranged outside the retaining hole.

9. A diaphragm pump as described in claim 8, wherein the detectable part is configured to have: a magnet that is detected by the detection part; a movable part to which the magnet is attached and which is housed in the retaining hole so as to be able to protrude or retract; and a stopper part that is disposed inside the retaining hole and limits the movement of the movable part.

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