JP4265820B2 - Chemical supply system - Google Patents

Description

  The present invention relates to a chemical solution supply system for discharging a chemical solution after being sucked by a pump and dropping the discharged chemical solution. Specifically, the present invention relates to a process for applying a chemical solution such as a photoresist solution in a semiconductor manufacturing apparatus. The present invention relates to a chemical solution supply system suitable for use in a chemical solution use process.

  In a chemical solution use process of a semiconductor manufacturing apparatus, a chemical solution supply system is used to apply a chemical solution such as a photoresist solution to a semiconductor wafer in a predetermined amount. For example, in the chemical liquid supply system disclosed in Patent Document 1, a pump for inhaling or discharging chemical liquid is configured as follows. That is, an incompressible medium is sealed between a flexible film filled with a chemical solution and a bellows that is elastically deformable in the axial direction, and the bellows is expanded or contracted by an actuator mechanism. Along with the expansion or contraction of the bellows, the flexible film is deformed through the incompressible medium, and the chemical solution is sucked or discharged. Further, a switching valve is provided on the downstream side and upstream side of the pump, and control is performed so that only the downstream switching valve is opened when the chemical solution is sucked and only the upstream switching valve is opened when the chemical solution is discharged.

  However, the conventional chemical supply system including a pump using an incompressible medium has problems that an expensive device such as an electropneumatic regulator or a stepping motor is required and the configuration is complicated.

  Therefore, in order to solve the problems in the conventional chemical solution supply system that uses an incompressible medium such as a liquid for expansion or compression of the flexible membrane, it is conceivable to use gas as the compressible medium. However, when the flexible membrane is expanded or compressed using compressed gas, it is necessary to set the pressure in consideration of the head (pipe height) assuming that the pump is set at a high position. The supply pressure of compressed gas inevitably increases.

When the supply pressure of compressed gas increases, an overshoot phenomenon occurs when the upstream switching valve is opened, causing an excessive amount of chemicals to drip at the start of dripping, or a water hammer phenomenon when the upstream switching valve is closed. As a result, there is a problem in that the liquid running out becomes poor at the end of dropping, and a chemical solution that should not be dropped is further dropped, thereby damaging the semiconductor wafer to which the chemical solution is dropped.
Japanese Patent Publication No. 7-123107

  In the present invention, the compressed gas supply system is simplified and inexpensively provided by using compressed gas as a pump working medium, and the supply pressure of the compressed gas is provided with allowance in consideration of the lift. The main purpose is also to eliminate problems such as drip defects.

  Hereinafter, effective means for solving the above-described problems will be described while showing effects and the like as necessary. In the following, in order to facilitate understanding, the corresponding configuration in the embodiment of the invention is appropriately shown in parentheses, but is not limited to the specific configuration shown in parentheses.

Means 1. The flexible membrane (diaphragm 20) partitions the pump chamber (pump chamber 21) and the working chamber (working chamber 22), and compressed gas (compressed air) is supplied to the working chamber (connected to the air source 50). Or the pump (pump 13) for discharging or sucking the chemical solution (resist solution R) by changing the volume of the pump chamber by evacuating the working chamber (connected to the vacuum source 54). ,
Switching means (the first switching valve 14 and the second switching) for switching to a state in which a compressed gas having a set pressure is supplied to the working chamber, a state in which the working chamber is opened to the atmosphere, or a state in which the working chamber is evacuated. Valve 53),
An open / close type shut-off valve (shut-off valve 45) provided between the pump and a position below the liquid drop (the tip nozzle position of the discharge pipe 43)
Switching from the state in which the working chamber is opened to the atmosphere to a state in which compressed gas is supplied to the working chamber by the switching means, and then switching the shut-off valve to the open position when a first set time (time T1) has elapsed. On the other hand, the switching chamber is switched from the state in which the working chamber is set to the set pressure to the state in which the working chamber is opened to the atmosphere by the switching means. A chemical solution supply system comprising control means (controller 56) for driving and controlling the switching means and the shutoff valve to switch to a closed position.

  In the above configuration, when the compressed gas having the set pressure is supplied to the working chamber, the flexible membrane is bent toward the side that compresses the volume of the pump chamber, and as a result, the chemical liquid is discharged from the pump. On the other hand, when the working chamber is evacuated, the flexible membrane bends to the side that expands the volume of the pump chamber, and as a result, the chemical is sucked into the pump. Here, since the set pressure of compressed gas is generally set to a relatively high pressure in consideration of the head, the pressure difference between the set pressure and the vacuum pressure becomes large, and it is assumed that switching between them is performed. In addition, an overshoot phenomenon occurs at the start of the dropping of the chemical liquid by the pump, and a water hammer phenomenon occurs at the end of the dropping of the chemical liquid to the pump, so that the dropping precision of the chemical liquid is lowered.

  Therefore, in the present means 1, switching to the atmospheric pressure between the set pressure and the vacuum pressure is enabled by the switching means, and the pressure in the working chamber is increased from the atmospheric pressure to the set pressure at the start of discharge of the chemical liquid. Thus, the control means controls so that the pressure in the working chamber is reduced from the set pressure to the atmospheric pressure at the end of the discharge of the chemical liquid. Thereby, the pressure difference at the time of the pressure switching by the switching means becomes small, and the rising speed and the falling speed to the set pressure at the start of the chemical liquid discharge or at the end of the chemical liquid discharge become gentle. In addition, the overshoot phenomenon is suppressed by switching the shut-off valve to the open position when the first set time elapses before reaching the set pressure when starting the dropping of the chemical solution, and set when the dropping of the chemical solution ends. The water hammer phenomenon can be suppressed by switching the shut-off valve to the closed position when the second set time elapses from the pressure.

  As described above, the overshoot phenomenon and the water hammer phenomenon can be suppressed even when compressed gas is used as the medium supplied to the working chamber and the set pressure is relatively high in consideration of the head. Therefore, highly accurate dropping of the chemical solution can be realized without using an incompressible medium, and a system with a simple configuration and an inexpensive cost can be provided.

  Mean 2. The chemical solution supply according to claim 1, further comprising a throttle passage (orifice 40) for restricting the compressed gas when the compressed gas is supplied to the working chamber and when the compressed gas is discharged from the working chamber. system.

  According to the means 2, due to the presence of the throttle passage, it takes a relatively long time to reach the set pressure when compressed gas is supplied to the working chamber. Similarly, the compressed gas is discharged from the working chamber. In some cases, it will take a relatively long time to reach atmospheric pressure. As a result, the first set time and the second set time can be set with a relatively large margin, and the first and second set times can be easily adjusted according to the viscosity of the chemical solution.

  Means 3. 3. The chemical solution supply system according to claim 2, wherein the throttle passage is constituted by an orifice (orifice 40).

  According to the means 3, by configuring the throttle passage by the orifice which is a fixed throttle passage, it is possible to secure the time from the atmospheric pressure to the set pressure and to reach from the set pressure to the atmospheric pressure with a simple and inexpensive configuration. Time can be secured. Moreover, since it is a fixed throttle passage, it is advantageous in that the throttle degree of the compressed gas does not change carelessly.

  Means 4. 3. The chemical solution supply system according to claim 2, wherein the throttle passage is provided with a needle for adjusting a throttle amount.

  According to the means 4, the throttle amount can be adjusted by adjusting the needle by narrowing the compressed air with the needle. As a result, the time characteristics from the atmospheric pressure to the set pressure and the time characteristics from the set pressure to the atmospheric pressure can be adjusted. Needle adjustment is also possible for changes in the usage environment of the chemical solution supply system, for example, significant differences in chemical solution viscosity It becomes possible to cope with.

  Means 5. Setting operation means (setting operation unit 57) for setting and operating the first setting time and the second setting time is provided, and the first setting time and the second setting time set by the setting operation means are stored in the control means. The chemical solution supply system according to any one of the above means 1 to 4, wherein the chemical solution supply system is held.

  According to the means 5, the first setting time and the second setting time can be set by the setting operation means, and the setting status is reflected in the control of the control means, so that the operation timing of the switching means and the shutoff valve is separated from them. The operation can be performed by operating at a remote position, and the workability of the setting operation is improved.

  Hereinafter, an embodiment embodying the invention will be described with reference to the drawings. In the present embodiment, a chemical supply system used in a production line for semiconductor devices or the like is embodied. First, a pump unit 11 that is a main part of the chemical supply system will be described with reference to FIGS. 1 and 2. To do.

  As shown in FIGS. 1 and 2, the pump unit 11 is roughly divided into a base 12, a pump 13 mounted on the base 12, and a first switching valve 14 that constitutes a switching means mounted on the pump 13. Are configured as a unit. The base 12 includes a mounting portion (not shown) for installing the pump unit 11 at an appropriate location.

  Here, the pump 13 will be described. The pump 13 includes a pump housing 15 fixed to the base 12. The pump housing 15 is formed with a recess 16 that opens on a side surface thereof. A chamber forming body 17 is accommodated in the recess 16. A valve housing 18 of the first switching valve 14 is attached to the side surface of the pump housing 15 with screws 19 so as to close the opening of the recess 16.

  The valve housing 18 and the chamber forming body 17 sandwich the peripheral edge of the diaphragm 20 constituting the flexible membrane. The gap between the valve housing 18 and the chamber forming body 17 is hermetically held by the peripheral edge of the diaphragm 20, and the space formed by the valve housing 18 and the chamber forming body 17 is separated from the pump chamber 21 by the diaphragm 20. It is partitioned into a working chamber 22. The pump side space defined by the diaphragm 20 is a pump chamber 21, and the valve side space is a working chamber 22.

  In the pump housing 15, a suction side joint 23 that constitutes a suction port is attached to the lower surface, and a suction passage 24 that connects the suction side joint 23 and the pump chamber 21 is formed. A suction side check valve 25 is provided in the suction passage 24. The suction side check valve 25 includes a valve seat 26 provided on the side opposite to the pump chamber 21 and a spherical body 27 that comes into contact with or separates from the valve seat 26. Therefore, when no pressure is applied to the sphere 27, the sphere 27 is in contact with the valve seat 26 by its own weight. The pressure difference applied to the suction side check valve 25 is closed when the pump chamber 21 side is high, while the suction side check valve 25 is opened when the pump chamber 21 side is low. .

  A discharge side joint 28 constituting a discharge port is attached to the upper surface of the pump housing 15, and a suction passage 29 that connects the discharge side joint 28 and the pump chamber 21 is formed. A discharge side check valve 30 is provided in the discharge passage 29. The discharge-side check valve 30 includes a valve seat 31 provided on the pump chamber 21 side and a sphere 32 that contacts or is separated from the valve seat 31. Therefore, when no pressure is applied to the sphere 32, the sphere 32 is in contact with the valve seat 31 by its own weight. When the pressure difference applied to the discharge side check valve 30 is high on the pump chamber 21 side, the discharge side check valve 30 is opened. On the other hand, when the pump chamber 21 side is low, the discharge side check valve 30 is closed. .

  With the above configuration, when the pump chamber 21 is pressurized by the operation of the diaphragm 20, the suction side check valve 25 is closed and the discharge side check valve 30 is opened, so that the chemical solution in the pump chamber 21 passes through the discharge passage 29. Discharged. On the other hand, when the pump chamber 21 is depressurized by the operation of the diaphragm 20, the suction side check valve 25 is opened, the discharge side check valve 30 is closed, and the chemical solution is sucked into the pump chamber 21 through the suction passage 24.

  Next, the first switching valve 14 will be described. The valve housing 18 is provided with an air supply side joint 33 constituting an air supply port and an exhaust side joint 34 constituting an exhaust port. In the valve housing 18, there are an air supply passage 35 communicating with the air supply side joint 33, an exhaust passage 36 (shown only in FIG. 3) communicating with the exhaust side joint 34, and an operation passage 37 communicating with the working chamber 22. Each is formed. An electromagnetic switching portion 38 is provided in front of the valve housing 18, and a wiring 39 for receiving a power source and an operation signal extends from the electromagnetic switching portion 38.

  The electromagnetic switching unit 38 includes an electromagnetic solenoid and a circuit for operating the solenoid, and the first switching valve 14 selectively switches the passage communicated with the operation passage 37 to the air supply passage 35 or the exhaust passage 36. It is configured as a position 3 port type electromagnetic switching valve. The exhaust passage 36 and the working passage 37 are communicated when the electromagnetic solenoid is OFF, and the air supply passage 35 and the working passage 37 are communicated when the electromagnetic solenoid is ON. Therefore, when the electromagnetic solenoid is turned on, the compressed gas is supplied to the working chamber 22 via the air supply passage 35 and the working passage 37, and presses the diaphragm 20 toward the pump chamber 21. On the other hand, when the electromagnetic solenoid is turned off, the compressed gas is discharged from the working chamber 22 through the working passage 37 and the exhaust passage 36, and the diaphragm 20 is not pressed toward the pump chamber 21 side.

  Here, in the working chamber 22, an orifice 40 constituting a throttle passage is formed on the way to the working passage 37. Accordingly, the supply of the compressed gas to the working chamber 22 or the discharge of the compressed gas from the working chamber 22 proceeds slowly by the throttling action of the orifice 40.

  Next, the overall configuration of the chemical supply system using the pump unit 11 configured as described above will be described based on the circuit diagram of FIG.

  One end of the suction pipe 41 is connected to the suction side of the pump unit 11, that is, the suction side joint 28 of the pump 13, and the other end of the suction pipe 41 is in the resist solution R as a chemical solution filled in the resist bottle 42. Led.

  A discharge pipe 43 is connected to the discharge side of the pump unit 11, that is, to the discharge side joint 23 of the pump 13. A shutoff valve 45 is connected to the discharge pipe 43 via a filter 44. The filter 44 removes dust and the like before the resist solution R is dropped from the tip nozzle of the discharge pipe 43. The shut-off valve 45 is an inexpensive air operated valve that can be simply switched between an open position and a closed position. In the present embodiment, a suck-back valve (not shown) is provided integrally with the shut-off valve. It is provided on the tip nozzle side from 45. Since the suck back valve is a well-known valve for preventing the resist solution R from dripping, detailed description thereof is omitted here. The tip nozzle of the discharge pipe 43 is directed downward and is disposed at a position where the chemical solution is dropped at the center position of the semiconductor wafer 47 rotating on the rotating plate 46.

  As described above, the resist solution R filled in the resist bottle 42 is guided along the flow path to the tip nozzle of the discharge pipe 43 through the suction pipe 41, the pump chamber 21 in the pump 13, and the discharge pipe 43. It has become.

  An air supply pipe 48 is connected to the air supply side of the pump unit 11, that is, the air supply side joint 33 of the first switching valve 14. The air supply pipe 48 is connected to an air source 50 through a pressure control valve 49. Then, air compressed by a compressor or the like is supplied from the air source 50, and the compressed air having the set pressure is supplied to the first switching valve 14 after setting the compressed air to a pressure set by the pressure control valve 49. It has come to be. A pressure gauge 51 is connected downstream of the pressure control valve 49 in the air supply pipe 48 so that it can be checked whether or not the set pressure is obtained.

  An exhaust pipe 52 is connected to the exhaust side of the pump unit 11, that is, to the exhaust side joint 34 of the first switching valve 14. The exhaust pipe 52 is connected to a second switching valve 53 which is a two-position three-port electromagnetic switching valve. The second switching valve 53 constitutes switching means together with the first switching valve 14. One of the remaining two ports of the second switching valve 53 is open to the atmosphere, and the other is connected to the vacuum source 54. When the electromagnetic solenoid provided in the second switching valve 53 is OFF, the inside of the exhaust pipe 52 is opened to the atmosphere, and when the electromagnetic solenoid is ON, the exhaust pipe 52 and the vacuum source 54 are communicated with each other. Accordingly, when the electromagnetic solenoid of the first switching valve 14 is OFF, the working chamber 22 is opened to the atmosphere when the electromagnetic solenoid of the second switching valve 53 is turned OFF. On the other hand, when the electromagnetic solenoid of the first switching valve 14 is OFF and the electromagnetic solenoid of the second switching valve 53 is turned ON, the working chamber 22 is connected to the vacuum source 54 and becomes lower than the atmospheric pressure, and the diaphragm 20 will bend toward the working chamber 22 side.

  The first switching valve 14, the second switching valve 53 and the shutoff valve 45 are connected to a controller 56 having a microcomputer or the like. The controller 56 constitutes a control means. The first switching valve 14, the second switching valve 53, and the shutoff valve 45 are individually turned on / off by the controller 56, thereby controlling the open / closed state. The controller 56 is connected to a setting operation unit 57 having input means such as a key or a dial. The setting operation unit 57 constitutes a setting operation means. The setting operation unit 57 switches the time T1 (first set time) from when the first switching valve 14 is switched to the open position to when the cutoff valve 45 is switched to the open position, and the first switching valve 14 is switched to the closed position. The time T2 (second set time) from when the shut-off valve 45 is switched to the closed position is individually set. The times T1 and T2 set here are stored and held by the controller 56. It is used when determining the switching timing of the shutoff valve 45.

  Next, the operation sequence of the chemical solution supply system will be described based on the time chart shown in FIG.

  In FIG. 4, when the first command signal from the controller 56 is first turned ON at the timing t1, the electromagnetic solenoid of the first switching valve 14 is turned ON and the first switching valve 14 is switched to the open position. Then, the compressed air set to the set pressure via the air source 50 and the pressure control valve 49 flows into the working chamber 22. At this time, since the compressed air flowing into the working chamber 22 is subjected to the throttling action of the orifice 40, the pressure in the working chamber 22 gradually increases and eventually reaches the set pressure. Since the diaphragm 20 presses the pump chamber 21 by the pressure in the working chamber 22, the pressure in the working chamber 22 becomes the discharge pressure of the resist solution R filled in the pump chamber 21 as it is. Therefore, when the pump discharge pressure is equal to the atmospheric pressure at the time t1, the pressure is gradually increased based on the throttle action of the orifice 40, and finally reaches the set pressure.

  Next, when the third command signal from the controller 56 is turned ON at the timing t2 when the time T1 set by the setting operation unit 57 has elapsed from t1, the shutoff valve 45 is switched to the open position. As a result, the discharge pipe 43 is opened, and the resist solution R is dropped from the tip nozzle of the discharge pipe 43 based on the pressure in the pump chamber 21. At the switching timing of the shut-off valve 45 to the open position, the pump discharge pressure is not suddenly increased from the vacuum pressure to the set pressure, but the pump discharge pressure is increased from the atmospheric pressure to the set pressure. Since the pump discharge pressure has not yet reached the set pressure, the overshoot phenomenon is greatly reduced, and the dropping state of the resist solution R from the tip nozzle can be maintained with higher accuracy than at the start of dropping. That is, the phenomenon that a large amount of the resist solution R is dropped at the start of dropping is eliminated, and the resist solution R can be evenly applied on the semiconductor wafer 47.

  At the timing t3, the first command signal from the controller 56 is turned OFF, and the first switching valve 14 is switched to the closed position. At this time, since the second switching valve 53 is in the closed position, the working chamber 22 is opened to the atmosphere. However, since it is affected by the restricting action of the orifice 40 when it is opened to the atmosphere, the pump discharge pressure does not immediately become atmospheric pressure, but gradually decreases, and finally reaches atmospheric pressure.

  Next, when the third command signal from the controller 56 is turned OFF at the timing t4 when the time T2 set by the setting operation unit 57 has elapsed from t3, the shutoff valve 45 is switched to the closed position. Thereby, the discharge pipe 43 is closed, and the dropping operation of the resist solution R is completed. At the switching timing of the shut-off valve 45 to the closed position, the pump discharge pressure is not lowered suddenly from the set pressure to the vacuum pressure, but is reduced from the set pressure to the atmospheric pressure. Since the difference is small and the pump discharge pressure has already been reduced to a pressure lower than the set pressure, the water hammer phenomenon is greatly reduced, and the liquid running out at the end of the dropping of the resist solution R from the tip nozzle is extremely large. Become good. That is, in practice, the set pressure of the pressure control valve 49 is a relatively high pressure in consideration of the head (pipe height), so that the shutoff valve is in a situation where the pump discharge pressure is at such a high set pressure. When 45 is switched to the closed position, there is a risk that a liquid shortage occurs and an excess resist solution R is applied to the semiconductor wafer R, but this problem can be solved.

  At the timing t5, the second command signal from the controller 56 is turned ON, and the second switching valve 53 is switched to the open position. Then, the working chamber 22 communicates with the vacuum source 54, and the pressure in the working chamber 22 is reduced so as to be lower than the atmospheric pressure. When the inside of the working chamber 22 is brought close to the vacuum pressure, the diaphragm 20 bends toward the working chamber 22 side, so that the resist solution R from the resist bottle 42 is sucked into the pump chamber 21. Thereafter, at the timing of t6, the second command signal from the controller 56 is turned OFF, and the second switching valve 53 is switched to the closed position. As a result, the operation of sucking the resist solution R into the pump chamber 21 is completed, and at the next timings t7 and t8, operations similar to those described above for t1 and t2 are executed. The operation of -t6) is repeated.

  Here, the setting method of the time T1 and the time T2 in the setting operation part 57 is demonstrated. When the viscosity of the resist solution R is low, the time T1 is set to be relatively short compared to when the viscosity of the resist solution R is high. This is because the resist solution R easily jumps on the semiconductor wafer 47 at the start of dropping because the viscosity is low, so that the resist solution R is evenly applied to the semiconductor wafer 47 by reducing the jump. is there. On the other hand, when the viscosity of the resist solution R is high, the time T2 is set to a relatively short time compared to the case where the viscosity of the resist solution R is low. This is because the high viscosity makes it easy for the resist solution R to run out at the end of the dropping, so that the switching valve 45 is switched to the closed position when the pump discharge pressure is relatively high to improve the running out of the solution. . The time T1 and the time T2 determine optimum values while performing appropriate inspections based on the above points. Since these settings can be performed by remote operation at the setting operation unit 57, the setting workability is high.

  The setting operation unit 57 has been described as performing the setting operation for the time T1 and the time T2, but t1, t3, t5 which are timings for further switching the first switching valve 14 and the second switching valve 53 in the setting operation unit 57. , T6 may be set.

  According to the embodiment described above in detail, the following excellent effects can be obtained.

  Since air, which is a gas, is used as a medium that is supplied to and discharged from the working chamber 22 of the pump 13 and controls the diaphragm 20, it can be configured without using expensive equipment such as a stepping motor and the configuration is simplified. . In addition, the configuration of the pump 13 itself is simple, and the shut-off valve 45 can also be a simple air operated valve that can be simply turned on / off. And cost reduction. In addition, since the single controller 56 controls all of the first switching valve 14, the second switching valve 53, and the shutoff valve 45, that is, the entire chemical supply system, the control system can be simplified. Can do.

  The pump discharge pressure is not suddenly increased from the vacuum pressure to the set pressure, but the pump discharge pressure is increased from the atmospheric pressure to the set pressure, and the switching of the first switching valve 14 to the open position and the cutoff valve are performed. In the stage where the first switching valve 14 is switched to the open position and is gradually pressurized by the throttle action of the orifice 40 (after T1 has elapsed), the shutoff valve 45 is not switched to the open position 45 at the same time. Is switched to the open position. Thereby, the overshoot phenomenon at the start of dropping is greatly reduced, and the dropping state of the resist solution R from the tip nozzle can be maintained with higher accuracy than at the start of dropping. As a result, the phenomenon that a large amount of the resist solution R is dropped at the start of dropping is eliminated, and the resist solution R can be evenly applied on the semiconductor wafer 47.

  Switching to the closed position of the first switching valve 14 and switching to the closed position of the shut-off valve 45 are not performed at the same time, and switching to the closed position of the first switching valve 14 is performed and the pressure is gradually reduced by the throttle action of the orifice 40. The shut-off valve 45 is switched to the closed position in the step (after T2). As a result, the water hammer phenomenon at the end of dropping is greatly reduced, and the liquid running out at the end of dropping of the resist solution R from the tip nozzle is extremely good. That is, in practice, the set pressure of the pressure control valve 49 is a relatively high pressure in consideration of the head (pipe height), so that the shutoff valve is in a situation where the pump discharge pressure is at such a high set pressure. When 45 is switched to the closed position, there is a possibility that a liquid shortage occurs and an excessive resist solution R is applied to the semiconductor wafer R, but this problem can be solved.

  In addition, the first switching valve 14 is switched to the closed position to temporarily set the working chamber 22 to atmospheric pressure, and then the second switching valve 53 is switched to the open position. Since the pressure state is switched in three stages of set pressure, atmospheric pressure, and vacuum pressure, the pressure is reduced based on the throttling action of the orifice 40 as compared with the case of immediately switching from the set pressure to the vacuum pressure. Will also be slow. Therefore, the degree of pressure reduction per unit time from the set pressure is reduced by switching the first switching valve 14 to the closed position, the water hammer phenomenon is further reduced, and the setting operation of the time T2 is very easy. It will be a thing.

  As described above, the dropping state of the resist solution R can be changed to the dropping start point and dropping end point only by supplying air to the working chamber 22 and controlling the ON / OFF timing of the simple ON / OFF switching type valves 14, 45, 53. As a result, the resist liquid R application process to the semiconductor wafer 47 can be performed with high accuracy.

  In the present embodiment, since the pump unit 11 is configured by integrating the pump 13 and the first switching valve 14, there is no piping between the pump 13 and the first switching valve 14, and the working chamber The length of the flow path reaching 22 can be shortened. As a result, the system configuration can be further simplified, and there is an advantage that the responsiveness to the opening / closing switching of the first switching valve 14 is increased.

  In addition, this invention is not limited to the content of description of the said embodiment, For example, you may implement as follows.

  That is, in the above embodiment, air has been described as an example of the compressible medium supplied to and discharged from the working chamber 22, but other gases such as nitrogen can be used in addition to air. In addition, although an example in which the fixed orifice 40 is used to throttle the air supplied to and discharged from the working chamber 22, a variable throttle such as a needle may be used.

  Further, the example in which the resist solution R is used as the chemical solution has been shown, but this is because the target for dropping the chemical solution is based on the semiconductor wafer 47. Therefore, the chemical solution and the dripping target of the chemical solution may be other than that.

  Further, the pressure is gradually changed when the pump discharge pressure is increased to the set pressure using the orifice 40 or when the pressure is reduced from the set pressure. Good. Even in this case, a three-stage pressure state of a set pressure, an atmospheric pressure, and a vacuum pressure is set, and the vacuum pressure for sucking the resist solution R in the pump 13 to the set pressure for discharging the resist solution R is set. This is because an abrupt pressure change can be alleviated by once creating a state in which the pressure is maintained at atmospheric pressure, and the above-described overshoot phenomenon and water hammer phenomenon can be alleviated. However, the configuration according to the above-described embodiment is superior in terms of suppressing these phenomena.

  Further, the operation is switched between the case where the working chamber 22 is opened to the atmosphere and the case where it is communicated with the vacuum source 54 by the second switching valve 53, and the orifice 40 is provided at the inlet to the working chamber 22. For this reason, even when the working chamber 22 is in communication with the vacuum source 54, it is affected by the throttling action of the orifice 40. However, the working chamber 22 is communicated with the vacuum source 54 in order to suck the resist solution R into the pump chamber 21, and the dropping process is interrupted in this situation. It is not necessary to receive the squeezing action by 40. Therefore, a vacuum passage that connects the working chamber 22 and the vacuum source 54 without passing through the orifice 40 may be separately formed. Specifically, the second switching valve 53 is omitted, the exhaust pipe 52 is always open to the atmosphere, and a switching valve for opening and closing the vacuum passage may be provided separately. Thereby, the suction | inhalation operation | work of the resist liquid R to the pump chamber 21 can be performed in a short time.

It is a front view which shows a pump unit in a chemical | medical solution supply system. It is the sectional view on the AA line of FIG. It is circuit explanatory drawing which shows the whole circuit of a chemical | medical solution supply system. It is a time chart which shows the operation | movement sequence of a chemical | medical solution supply system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Pump unit, 13 ... Pump, 14 ... 1st switching valve which comprises switching means, 20 ... Diaphragm which comprises a flexible membrane, 21 ... Pump chamber, 22 ... Actuation chamber, 40 ... Orifice, 45 ... Shut-off valve 53 ... second switching valve constituting switching means, 56 ... controller constituting control means, 57 ... setting operation section constituting setting operation means, R ... resist solution as chemical solution, T1, T2 ... first setting time And the second set time.

Claims (5)

The pump chamber and the working chamber are partitioned by a flexible membrane, and the compressed gas is supplied to the working chamber or the working chamber is evacuated to change the volume of the pump chamber, thereby discharging the chemical liquid. Or a pump to inhale,
Switching means for switching to either a state in which a compressed gas having a set pressure is supplied to the working chamber, a state in which the working chamber is opened to the atmosphere, or a state in which the working chamber is evacuated;
An open / close shut-off valve provided between the pump and a position below the medicine droplet;
Switching from the state where the working chamber is opened to the atmosphere to a state where compressed gas is supplied to the working chamber by the switching means, and then switching the shut-off valve to the open position when a first set time has passed, The switching means is switched from the state where the working chamber is set to the set pressure to the state where the working chamber is opened to the atmosphere by the switching means, and then the switching valve is switched to the closed position when a second set time has elapsed. And a control means for drivingly controlling the shutoff valve.   2. The chemical supply system according to claim 1, further comprising a throttle passage for restricting the compressed gas when the compressed gas is supplied to the working chamber and when the compressed gas is discharged from the working chamber.   3. The chemical solution supply system according to claim 2, wherein the throttle passage is configured by an orifice.   The chemical solution supply system according to claim 2, wherein the throttle passage includes a needle for adjusting a throttle amount.   Setting operation means for setting and operating the first setting time and the second setting time is provided, and the first setting time and the second setting time set by the setting operation means are stored and held in the control means. The chemical solution supply system according to any one of claims 1 to 4, wherein

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