JP7751613B2 - diaphragm pump - Google Patents

Description

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

Diaphragm pumps are installed in the chemical supply line of semiconductor manufacturing equipment and are used to control the supply of chemicals to semiconductor wafers. A diaphragm separates a space formed inside the body into a chemical chamber and a drive chamber. The diaphragm is displaceable and separates the space between 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. A magnet and magnet position sensor are attached to the diaphragm to detect 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 this connecting portion with a screw, and a magnet position sensor is installed on the body side. The diaphragm position can be detected from the position of this magnet, allowing the amount of chemicals discharged to be controlled to a predetermined amount (see, for example, Patent Document 1).

In addition, to suppress particle generation from the diaphragm surface, 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.)

Japanese Patent Application Laid-Open No. 2006-46284 Patent No. 6602553

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, making it prone to deterioration.

Furthermore, even if a diaphragm is made from 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 tiny 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 causes of particle generation as much as possible and suppress particle generation.

One aspect of a diaphragm pump designed 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 is configured as follows: the diaphragm has a membrane-like diaphragm formed from resin, and a space in which the diaphragm is displaceably positioned, 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 that can move in accordance with the diaphragm; and a detector that detects the displacement of the diaphragm based on the position of the detectable part.

In a diaphragm pump with 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, as 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 with the above configuration, which has the function of detecting diaphragm displacement, it is possible to improve the durability of the diaphragm and suppress particle generation.

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

In a diaphragm pump with the above configuration, the surface of the diaphragm is not machined, so there are no irregularities from cutting marks on the surface of the diaphragm, and it is smooth. This prevents particles from being generated due to the irregularities on the diaphragm.

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

In a diaphragm pump with 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 can affect semiconductor manufacturing.

(4) In the diaphragm pump described in any one of (1) to (3), it is preferable that the distance that the detected part can move is smaller than the maximum stroke amount of the diaphragm.

In a diaphragm pump with the above configuration, the detected part follows the diaphragm for part of the diaphragm's stroke and does not follow the diaphragm for the rest of the stroke, which means the diaphragm is less likely to rub against the moving part and wear out, improving the durability of the diaphragm.

(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.

In a diaphragm pump with the above configuration, the diaphragm has a thin thickness of 0.1 mm or more and 0.3 mm or less, 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, a diaphragm pump with the above configuration can be expected to have good discharge performance. Furthermore, because the diaphragm is thin and less susceptible to deterioration due to stress concentration during deformation, particle generation can be suppressed.

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

In a diaphragm pump with the above configuration, the biasing force of the biasing member that biases the detected part toward the space 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 part.

(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 is deflected when the diaphragm is in an unloaded state.

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

(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 detected part and a biasing member that biases the detected part toward the space, and the detection part is arranged outside the retaining hole.

In a diaphragm pump with 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 chemicals that have permeated the diaphragm.

(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 disposed inside the retaining hole and limits the movement of the movable part.

The diaphragm pump with the above configuration suppresses particles generated from the detected part, while allowing the detected part to be movably positioned in the body independently of the diaphragm in a compact structure.

The technology disclosed in this specification makes it possible to improve the durability of the diaphragm and suppress particle generation in a diaphragm pump that has the function of detecting diaphragm displacement.

FIG. 1 is a cross-sectional view of a diaphragm pump showing an unloaded state. FIG. 2 is a cross-sectional view of the diaphragm pump, showing a discharge completion state. FIG. 2 is a cross-sectional view of the diaphragm pump, showing the suction completion state. FIG. 2 is an enlarged view of part A1 in FIG. FIG. 3 is an enlarged view of part A2 in FIG. 2. FIG. FIG. 6 is an enlarged view of part A3 in FIG. 5 . FIG. 10 is a cross-sectional view showing a modified example of the diaphragm pump.

One embodiment of the present invention will be described below with reference to the drawings. This specification discloses a diaphragm pump that is incorporated into semiconductor manufacturing equipment and used to supply resist liquid.

The diaphragm pump 1 shown in Figures 1 to 3 is installed in a chemical liquid supply line of a semiconductor manufacturing device and is used to control the supply of chemical liquid to semiconductor wafers (not shown). The diaphragm pump 1 of this embodiment controls resist liquid, 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, causing the diaphragm 20 shown in Figure 1 to displace toward the chemical liquid chamber 14 and the drive chamber 15, as shown in Figures 2 and 3, and allowing the resist liquid to be discharged and sucked in predetermined amounts.

As shown in Figure 1, the diaphragm pump 1 comprises a body 10, a diaphragm 20, a detected part 3, and a detection part 4.

The body 10 is made up of 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.

The first housing 11 and the second housing 12 have a first concave surface 111 and a second concave surface 121 formed in a generally dome shape on their abutting surfaces. The first concave surface 111 and the second concave surface 121 of the body 10 form a space 13 between the first housing 11 and the second housing 12. A diaphragm 20 is displaceably disposed in the space 13. The diaphragm 20 is membrane-shaped, and its outer edge is sandwiched between the first housing 11 and the second housing 12, airtightly dividing the space 13 into a chemical solution chamber 14 and a drive chamber 15.

The first housing 11 is formed with an inlet flow path 16 and an outlet flow path 17 that open to the first concave surface 111, forming flow paths for flowing resist liquid in and out of the chemical chamber 14. The second housing 12 is formed with an operation flow path (not shown) that opens to the second concave surface 121, forming a flow path for supplying and exhausting operation air to and from the drive chamber 15. Operation air is an example of an "operation fluid."

The diaphragm 20 is made of an easily moldable resin. 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 that fixed amount of fluid was counted using a particle counter. As a result, they confirmed that the PFA diaphragm generated fewer particles than the PTFE diaphragm.

The raw material for the diaphragm 20 may also be fluororesins 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.

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, it 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 greater than 0.3 mm, the tension acting on the diaphragm 20 will be too great, which may reduce the pump's discharge performance or generate particles due to stress concentration.

The diaphragm 20 is molded so that the portion positioned 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 a predetermined distance L1 away from the diaphragm 20, preventing tension from acting on 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 on the diaphragm 20. The position of the diaphragm 20 in an unloaded state is referred to as the "neutral position P1."

In this embodiment, the diaphragm 20 is formed into the shape shown in Figure 1 by extrusion molding, and then the surface is smoothed by roll molding. This is to prevent particles from being generated on the surface of the diaphragm 20.

The body 10 has a cylindrical retaining hole 122 opened 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 in the body 10 so that it can come into contact with the surface of the diaphragm 20 located on the drive chamber 15 side, and can move in conjunction with the diaphragm 20.

The configuration of the detected part 3 will be described in detail 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.

As shown in Figures 4 to 7, the detected part 3 is composed of a pump screw 32, a magnet 33, and a plunger 34, with the magnet 33 sandwiched between the pump screw 32 and the plunger 34. The pump screw 32 and plunger 34 are examples of a "moving part."

The detected part 3 is held in the holding hole 122 using a guide member 38 and a bushing 39 so that it can move in the displacement direction of the diaphragm 20 (left-right direction in the figure). The detected part 3 is constantly biased by a spring 3 in a direction that causes it to protrude from the holding hole 122.

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

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, into 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. Radial wobble of the magnet 33 is suppressed by the stepped portion 342 and the leg 321 of the pump screw 32.

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 on one side, and an insertion hole 383 is formed in the closed surface 382. The guide member 38 is fitted into the retaining hole 122 with the open end abutting against the bottom surface of the retaining hole 122.

The head 322 of the pump screw 32 has a flange 323 that protrudes radially outward along the outer periphery of the end face 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.

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 detectable 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 flange 323 of the detectable part 3 is engaged with the closing surface 382, limiting its movement in the protruding direction from the retaining hole 122 into the drive chamber 15. In other words, the maximum amount of protrusion of the detectable part 3 into the drive chamber 15 is specified. The position of the detectable part 3 in this case is referred to as the "off position P11."

As shown in FIG. 7 , the movement of the detectable 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 detectable part 3 into the drive chamber 15 is specified. The position of the detectable 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 bottomed hole 122 form an example of a "stopper part."

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

The distance L3 traveled by the detected portion 3 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 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 portion 3 contacts the diaphragm 20 during part of its stroke, as shown in Figures 6 and 7, and does not contact the diaphragm 20 during the remainder of its stroke, as shown in Figures 4 to 6. This reduces the area over which the diaphragm 20 comes into contact with the detected portion 3, thereby suppressing wear on the diaphragm 20.

The movement distance L3 is preferably 50% or less of the maximum stroke amount. 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 on the diaphragm 20. More preferably, the movement distance L3 is 30% or less of the maximum stroke amount. By having the diaphragm 20 come into contact with the detected part 3 just before reaching the full stroke position P4, the load that the diaphragm 20 receives from the detected part 3 is reduced, improving the durability of the diaphragm 20.

The diaphragm pump 1 discharges and sucks resist liquid by creating positive and negative pressure states in the drive chamber 15. Therefore, the spring 36 is positioned not to displace the diaphragm 20, but to return 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 apply a load to the diaphragm 20 that is not significantly greater than the tension of the diaphragm 20. In this embodiment, the diaphragm 20 is thin, with a thickness of 0.1 mm to 0.3 mm, and has a low tension, so the biasing force of the spring 36 is set to 0.05 N to 0.15 N.

The bushing 39 is press-fit into the retaining hole 122 until it abuts against the guide member 38, positioning and holding 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 bushing 39 are press-fit 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 surface of the retaining hole 122 and the outer surface of the plunger 34, and slidably holds the plunger 34.

The pump screw 32, plunger 34, guide member 38, and bushing 39 are made of fluororesin. It is desirable to form these using 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.

Returning to Figure 1, the detection unit 4 is a magnetic sensor that detects the position of the detected part 3. The detection unit 4 is positioned 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 positioned in the ON position P12, the detection unit 4 sends a detection signal to the host controller (not shown), and when the detected part 3 is not positioned in the ON position P12, the detection unit 4 does not send a detection signal to the host controller (not shown).

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

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

The diaphragm 20 is positioned at the discharge completion position P2, away from the detected portion 3, which is positioned at the off position P11. Furthermore, the diaphragm 20 is attached to the body 10 in a state in which it bends 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 that is attached to the body 10 in a flat state when in an unloaded state.

The detector 4 shown in Figure 2 does not detect the magnet 33 of the detectable part 3 when it is in the OFF position P11. Therefore, the detector 4 does not send a detection signal to the upper controller (not shown).

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 (toward the drive chamber 15) due to its own elastic force, and the sealing force of the diaphragm 20 against the first concave surface 111 decreases.

As shown in Figure 5, the first concave surface 111 has multiple grooves 112 formed in the circumferential direction, and multiple 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).

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 able to displace toward the second concave surface 121 (drive chamber 15).

As shown in FIG. 6, the diaphragm 20 moves from the discharge completion position P2 to the contact position P3 where it contacts the contact surface 343 of the detected part 3 while separated from the detected part 3. Therefore, while the diaphragm 20 moves 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 in the off position P11.

When the diaphragm 20 deforms by bulging from the contact 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.

As shown in Figure 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 reaches its maximum.

As shown in Figure 7, the head 322 of the pump screw 32 hits the bottom of the retaining hole 122, restricting movement of the detected part 3 in the retraction direction and positioning it in 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 in the ON position P12.

The detected part 3 has a flat contact surface 343, and the corners 344 of this contact surface 343 are smoothly curved. 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 for deterioration due to stress concentration to occur in the part that comes into contact with the detected part 3. This prevents particles from being generated in areas that have deteriorated due to stress concentration.

When the detected part 3 is placed in the ON position P12, the detection part 4 shown in FIG. 3 detects the magnet 33 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 in a predetermined amount of resist liquid.

In the diaphragm pump 1 shown in Figure 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 Figure 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.

As shown in Figure 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.

The detected part 3 and 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 in conjunction with 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.

In addition, the biasing force of the spring 36 is small, at between 0.05 N and 0.15 N. As a result, the load acting on the part of the detected part 3 that comes into contact with the diaphragm 20 is small. Therefore, even if the detected part 3 comes into contact with the diaphragm 20 and moves in conjunction with the diaphragm 20, the part of the diaphragm 20 that comes into contact with the detected part 3 is less likely to wear out, and particles are less likely to be generated.

As shown in Figure 5, the flange 323 of the pump screw 32 is engaged with the closing surface 382 of the guide member 38, preventing the detected part 3 from moving in the protruding direction beyond the OFF position P11. Therefore, the diaphragm 20 is separated from the detected part 3 while moving from the abutment position P3 to the discharge completion position P2, so it is not subjected to loads other than the operating air and is less likely to deteriorate due to stress concentration.

When the detected part 3 moves from the ON position P12 to the OFF position P11, the detection part 4 shown in FIG. 2 can no longer detect the magnet 33 and therefore no longer sends 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).

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

When the diaphragm 20 is unloaded, the portion of the diaphragm 20 that corresponds to the space 13 is attached to the body 10 in a state where it bends toward the first concave surface 111, 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, ensuring a stable discharge rate of resist liquid.

The diaphragm 20 is thin and the tension acting on it is small, so it easily deforms in response to pressure fluctuations in the drive chamber 15. Therefore, the diaphragm pump 1 can be expected to have good discharge performance. 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.

The diaphragm 20 is made from PFA, which is less likely to generate particles. Furthermore, the diaphragm 20 is formed by extrusion and roll molding, which eliminates unevenness caused by cutting marks and reduces particle generation. Therefore, even if the diaphragm 20 is repeatedly deformed, particles are less likely to be generated from its surface.

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 it. As a result, the tension acting on the diaphragm 20 is small, the diaphragm 20 is less susceptible to deterioration due to stress concentration, and particles are less likely to be generated from deteriorated parts.

As shown in Figures 5 to 7, in the diaphragm pump 1, the detected part 3 moves while contacting 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 part 3 and wear out compared to when the detected part contacts the diaphragm for the entire stroke of the diaphragm, improving the durability of the diaphragm 20.

Even if the diaphragm 20 rubs against the detected part 3 and wears down, generating particles, the detected part 3 is located on the drive chamber 15 side, so the particles are contained within the drive chamber 15 and do not mix with the resist liquid.

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

In addition, the diaphragm pump 1 has the detectable portion 3 slidably disposed in the retaining hole 122, and the flange portion 323 of the pump screw 32 abuts against 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 detectable portion 3, thereby suppressing particles generated by the detectable portion 3. Furthermore, the diaphragm pump 1 has a compact structure, and the detectable portion 3 can be movably disposed in the body 10 while being independent from the diaphragm 20.

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 the function of detecting the displacement of the diaphragm 20, the durability of the diaphragm 20 can be improved and particle generation can be suppressed.

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

For example, the diaphragm 20 may be formed by either extrusion molding or roll molding. The diaphragm 20 may also 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 tube-shaped extrusion into a sheet.

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

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 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, resulting in wear.

For example, as shown in Figure 8, the diaphragm 20 may be placed in the space 13 in a flat state when no load is applied.

For example, the diaphragm 20 may be molded in a flat sheet shape. However, by molding the portion of the diaphragm 20 that is placed in the space 13 into a curved shape, it is easier to place the diaphragm 20 in the body 10 with the portion corresponding to the space 13 bent when no load is applied.

For example, the detection unit 4 may be arranged so as to communicate with the retaining hole 122.

For example, the pump screw 32 may be divided into a first part that engages with the guide member 38 and a second part that has a male threaded portion 321a that fastens to the female threaded hole 341 of the plunger 34.

For example, the movable part may be constructed as a single part, and the magnet 33 may be attached to the movable part by insert molding.

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

Claims (8)

A diaphragm pump that sucks and discharges a predetermined amount of chemical liquid to be supplied to a semiconductor wafer,
a film-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 solution chamber into which the chemical solution flows and a drive chamber to which an operating fluid for displacing the diaphragm is supplied;
a detected portion that is held by the body so as to be able to come into contact with a surface of the diaphragm that is located on the drive chamber side and that is movable following the diaphragm;
a detection unit that detects a displacement of the diaphragm based on the position of the detected portion;
and
The movable distance of the detection part is smaller than the maximum stroke amount of the diaphragm.
A diaphragm pump configured as follows. 2. The diaphragm pump according to claim 1,
The diaphragm is formed by extrusion, rolling, or both.
A diaphragm pump configured as follows. 3. The diaphragm pump according to claim 1,
The diaphragm is made of PFA.
A diaphragm pump configured as follows . 3. The diaphragm pump according to claim 1,
The diaphragm has a film thickness of 0.1 mm or more and 0.3 mm or less.
A diaphragm pump configured as follows. A diaphragm pump that sucks and discharges a predetermined amount of chemical liquid to be supplied to a semiconductor wafer,
a film-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 solution chamber into which the chemical solution flows and a drive chamber to which an operating fluid for displacing the diaphragm is supplied;
a detected portion that is held by the body so as to be able to come into contact with a surface of the diaphragm that is located on the drive chamber side and that is movable following the diaphragm;
a detection unit that detects a displacement of the diaphragm based on the position of the detected portion;
and
the diaphragm has a film thickness of 0.1 mm or more and 0.3 mm or less;
a biasing member that biases the detected portion toward the space portion,
The biasing force of the biasing member is 0.05 N or more and 0.15 N or less.
A diaphragm pump configured as follows. A diaphragm pump that sucks and discharges a predetermined amount of chemical liquid to be supplied to a semiconductor wafer,
a film-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 solution chamber into which the chemical solution flows and a drive chamber to which an operating fluid for displacing the diaphragm is supplied;
a detected portion that is held by the body so as to be able to come into contact with a surface of the diaphragm that is located on the drive chamber side and that is movable following the diaphragm;
a detection unit that detects a displacement of the diaphragm based on the position of the detected portion;
and
The diaphragm is disposed in the body in a state where a portion of the diaphragm corresponding to the space portion is deflected when the diaphragm is in an unloaded state.
A diaphragm pump configured as follows. A diaphragm pump that sucks and discharges a predetermined amount of chemical liquid to be supplied to a semiconductor wafer,
a film-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 solution chamber into which the chemical solution flows and a drive chamber to which an operating fluid for displacing the diaphragm is supplied;
a detected portion that is held by the body so as to be able to come into contact with a surface of the diaphragm that is located on the drive chamber side and that is movable following the diaphragm;
a detection unit that detects a displacement of the diaphragm based on the position of the detected portion;
and
the body has a bottomed retaining hole that opens to an inner wall of the drive chamber,
The holding hole accommodates the detected portion and a biasing member that biases the detected portion toward the space portion,
The detection unit is disposed outside the holding hole.
A diaphragm pump configured as follows. 8. The diaphragm pump according to claim 7,
The detected part is
a magnet to be detected by the detection unit;
a movable portion to which the magnet is attached and which is accommodated in the holding hole so as to be able to protrude or retract;
a stopper portion disposed inside the holding hole and limiting movement of the movable portion;
having
A diaphragm pump configured as follows.