JP4986125B2 - Mass flow control device and gas supply unit - Google Patents

Description

  The present invention relates to an improvement of a mass flow controller and a gas supply unit used for gas supply, particularly for supplying semiconductor manufacturing gas.

Gas supply used for semiconductor manufacturing requires high purity of process gas and high flow rate accuracy, and various fluid control devices for controlling gas supply are integrated into an integrated unit.
For example, the gas supply unit 151 shown in FIG. 6 includes a manual shutoff valve S, a pressure control valve R, a pressure sensor T, a pneumatic drive shutoff valve A1, a mass flow controller M, and a pneumatic drive shutoff valve A2 in series from the upstream side. The devices are arranged, connected to each other by channel blocks V2 to V6 having V-shaped channels (not shown), and joint blocks V1 and V7 are connected to the upstream and downstream ends. Then, a flow rate setting signal is output from the control device (not shown) to the mass flow controller M, and an operation signal is output to the electromagnetic valve (not shown), and the pneumatic drive cutoff valve (A1,. A2) is configured to operate.

At this time, the mass flow controller M receives the flow rate setting signal and adjusts the opening degree of the control valve so as to coincide with the set flow rate. However, the operation signal output to the solenoid valve operates the solenoid valve, and the pneumatic drive cutoff valves (A1, A2) are activated only when the necessary air pressure reaches the pneumatic drive cutoff valves (A1, A2). Therefore, the operation start timings of the mass flow controller M and the pneumatically driven cutoff valves (A1, A2) are shifted.
For example, when a process gas is introduced, if a deviation occurs in the operation start timing, the mass flow controller M starts the flow control even though the pneumatic drive cutoff valves (A1, A2) are not open. The mass flow controller M adjusts the opening degree of the control valve so as to correspond to the flow rate setting signal. However, since the process gas does not actually flow, the mass flow controller M controls the control valve in the opening direction more than necessary. It becomes.
Thus, when the pneumatically driven shut-off valves (A1, A2) are opened, process gas exceeding the flow rate instructed by the flow rate setting signal flows downstream (so-called overshoot phenomenon), and the control flow rate. There was a problem that the accuracy of was worse.
Further, in order to ensure the accuracy of the flow control of the mass flow controller M, a pressure control valve R for controlling the pressure of the gas supplied to the mass flow controller M must be arranged upstream of the mass flow controller M, and the gas supply unit There was a problem that the size of 151 increased.

  A mass flow controller for improving the control flow accuracy is described in, for example, Patent Document 1 or Patent Document 2. Patent Document 1 describes a mass flow controller in which a vertical flow path is provided on the downstream side of a flow control valve of a mass flow controller, and a shut-off valve that opens and closes the flow path is integrally opposed in the same body as the mass flow controller. ing. Furthermore, a switch for instructing the two-position operation of opening or closing the shut-off valve is provided, and an instruction signal of this switch is taken into the control circuit unit of the mass flow controller to link the control of the flow control valve and the shut-off valve. Are listed.

  Patent Document 2 discloses that an upstream side of a gas flow path is a verification valve section for opening and closing the flow path, a verification tank section having a predetermined capacity, and a pressure detection signal by detecting the pressure of the fluid. A mass flow rate control device configured to include a pressure control unit that outputs a pressure control unit that controls to perform a mass flow rate verification operation using a verification valve, a verification tank unit, and a pressure detection unit. It is disclosed. Further, a zero point measuring valve is provided on the downstream side of the gas flow path, and an electromagnetic three-way valve for operating the verification valve and the zero point measuring valve is incorporated.

Japanese Patent Laid-Open No. 11-154022 (FIGS. 1 and 2) JP 2006-38832 A (FIGS. 7 and 9)

  First, in order to incorporate the mass flow control device into the gas supply unit, there are dimensional restrictions. That is, a total length of 99.5 mm × width of 38.15 mm (mainly used in Japan = 1.5 ”size) or a total length of 105 mm × width of 28.6 mm (mainly used in the US = 1.125 "size) must be satisfied.

  According to the technique disclosed in Patent Document 1, there is a problem that the air inlet / outlet member protrudes below the mass flow controller and hinders the integration unit. In addition, since the switch for introducing / extracting air for driving the shut-off valve and the shut-off valve are performed through the pneumatic secondary pipe, there is still a problem that the operation delay of the shut-off valve cannot be solved.

In addition, according to the technique disclosed in Patent Document 2, the configuration of how to provide an electromagnetic three-way valve with respect to a verification valve or a zero-point measurement valve is not shown. There was a problem that the problem of operation delay could not be solved.
In other words, shut-off valves described in Patent Document 2 is intended to cut off the pressing channel to urge directly a metallic diaphragm hydraulic pressure metal diaphragm valve seat. However, since a distributed load is applied to the metallic diaphragm, a sufficient cutoff performance cannot be exhibited with a generally supplied air pressure (for example, 0.4 to 0.7 MPa). Therefore, the shut-off valve and the electromagnetic valve cannot be accommodated in the lower part of the mass flow control device, which has been an obstacle to the compact integration of the gas supply unit.

  The present invention has been made in order to solve the above-described problems. A compact mass flow control device that eliminates the overshoot phenomenon of flow control due to the operation delay of the shut-off valve and enables integration into an integrated unit, and this It aims at providing the compact gas supply unit provided with the mass flow control apparatus.

In order to achieve the above object, a mass flow control device of the present invention includes at least a flow control valve mechanism for controlling a mass flow by changing a valve opening degree by a valve drive signal, and a flow setting signal input from the outside. And a flow rate control valve control means for outputting the valve drive signal to the flow rate control valve mechanism based on the flow rate control valve mechanism, wherein the working gas is provided upstream and / or downstream of the flow rate control valve mechanism. A shut-off valve mechanism that is opened and closed by supplying and exhausting gas is provided, and a working chamber that supplies and discharges working gas in the shut-off valve mechanism and a flow path of a solenoid valve mechanism that feeds and exhausts the working gas are directly communicated with each other. The shut-off valve mechanism and the solenoid valve mechanism are integrally provided in the valve block body of the mass flow control device, and the shut-off valve mechanism is provided with the mass flow control device. A valve chamber provided in the valve block body, an inflow path through which fluid flows into the valve chamber, an outflow path through which fluid flows out from the valve chamber, an inflow path in the inflow path, and an outflow path in the outflow path A valve seat provided on any one of the valve ports, and a metal seat that is disposed so as to define the valve chamber so as to face the valve seat, and that is in contact with the valve seat and blocks the valve port. And a pressing means for pressing the diaphragm valve body, the pressing means being an actuator made of an elastic body disposed on the opposite side of the valve chamber so as to face the diaphragm valve body a plate, actuation always tip is interposed between the diaphragm valve member and the actuator plate and the pressing protrusion which is in contact with the central portion of the diaphragm valve element, the working gas is partitioned by the actuator plate is supplied and discharged And the flow control valve control means outputs a solenoid valve drive signal for operating the solenoid valve mechanism, and synchronizes the valve drive signal and the solenoid valve drive signal. Yes.

  Therefore, the valve block body of the mass flow control device is provided with the shut-off valve mechanism and the solenoid valve mechanism as one body, and the flow control valve mechanism and the solenoid valve mechanism are controlled to synchronize with each other. The supply and discharge of the working gas to the valve mechanism becomes the shortest, the operation timings of the flow control valve mechanism and the shutoff valve mechanism are synchronized, and the flow control overshoot phenomenon that occurs particularly when the valve is opened can be prevented.

The solenoid valve mechanism includes a three-way valve body, a three-way valve chamber in which the three-way valve body is built, a working gas input port for introducing a working gas into the three-way valve chamber, and a working gas communicating with the working chamber. An output port, a three-way valve first valve seat provided around the communication between the three-way valve chamber and the working gas input port; and the three-way valve chamber provided to face the three-way valve first valve seat An exhaust port, a three-way valve second valve seat provided around the communication between the three-way valve chamber and the exhaust port, and an electromagnetic coil for operating the three-way valve body when an operating voltage is applied. it can.
According to these configurations, it is easy to incorporate the shut-off valve mechanism and the solenoid valve mechanism in the valve block body of the mass flow control device.

  Further, in the present invention, a flow rate detecting means for detecting a flow rate and outputting a flow rate signal and a pressure detection means for detecting the pressure of the fluid and outputting a pressure detection signal are provided in the flow path for flowing the fluid, The flow rate control valve control means includes a first control mode for controlling the flow rate based on the flow rate signal and the flow rate setting signal without using the pressure detection signal, a pressure change amount obtained from the pressure detection signal, and the The second control mode for controlling the flow rate based on the flow rate setting signal can be selectively switched.

  The present invention provides a gas supply unit in which a plurality of fluid control devices connected via a plurality of flow path blocks are mounted on an upper surface of a base plate, wherein at least one of the fluid control devices is any one of claims 1 to 4. It can be set as the gas supply unit which is the mass flow control device prescribed | regulated.

  Therefore, since the necessary shut-off valve mechanism is provided inside the mass flow control device, the gas supply unit can be greatly reduced in size and the dead space is minimized, so that the gas replacement property and the high purity of the gas can be achieved. It becomes easy. Furthermore, since the control of the shutoff valve mechanism can be performed by the mass flow control device, the wiring of the gas supply unit, the working gas piping, and the control device are simplified.

  According to the present invention, the shutoff valve mechanism and the solenoid valve mechanism are integrally provided in the valve block body of the mass flow control device, and control is performed so that the operations of the flow control valve mechanism and the solenoid valve mechanism are synchronized. The supply and discharge of the working gas from the valve mechanism to the shut-off valve mechanism is minimized, the operation timing of the flow control valve mechanism and the shut-off valve mechanism is synchronized, and in particular, the flow control overshoot phenomenon that occurs when the valve is opened can be prevented. A compact mass flow rate control device that can be used.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is an example of a mass flow control device according to an embodiment of the present invention. FIG. 2 is an enlarged view showing a shutoff valve device of the mass flow control device according to the embodiment of the present invention. FIG. 3 is an implementation comparative example of the present invention and the prior art. FIG. 4 shows another example of the mass flow control device according to the embodiment of the present invention. FIG. 5 shows an example of the gas supply unit according to the embodiment of the present invention.

  As shown in FIG. 1, the mass flow controller 50 includes a mass flow detector 8, a flow control valve mechanism 10, and a controller 18 including, for example, a microcomputer. The mass flow rate detection means 8 includes a bypass pipe 12, a sensor pipe 14, a sensor circuit 16, and the like, and outputs a flow rate signal S1 detected here to the control means 18. The flow control valve mechanism 10 receives the valve drive signal S2 output from the flow control valve 20, the actuator 26 that drives the flow control valve 20, and the control means 18, and outputs a valve drive voltage toward the actuator 26. Etc. Then, the control means 18 controls the valve of the flow rate control valve 20 so that the flow rate indicated by the flow rate setting signal S0 inputted from the outside such as a host computer and the flow rate indicated by the flow rate signal S1 coincide with each other. The opening can be controlled.

On the other hand, on the upstream side of the mass flow control device 50, a shutoff valve device 52, a test tank unit 56 having a predetermined capacity, and a pressure detection that detects the pressure of gas as a fluid and outputs a pressure detection signal. Means 58. The test tank unit 56 includes a tank main body 68 made of, for example, stainless steel. The tank main body 68 is set to a predetermined flow rate, for example, a capacity of about 40 cm ³ , and the flowing gas is always in the tank main body 68. Is supposed to pass through. Further, a platinum temperature sensor, for example, is attached as a temperature detecting means 70 in the vicinity of the tank main body 68, that is, here, the upper surface of the ceiling of the tank main body 68, and a signal indicating the detected temperature is sent to the control means 18. It can be input.

  The flow rate control valve mechanism 10 can be controlled in a second control mode to be described later using the pressure detection signal S5 output from the pressure detection means 58. Further, the control means 18 performs a mass flow rate verification operation for verifying the accuracy of the flow rate control of the flow rate control valve 20 using the shutoff valve device 52, the verification tank unit 56, and the pressure detection unit 58. It can also be configured to be controllable.

Further, a shutoff valve device 54 is provided downstream of the mass flow control device 50, and a zero point verification operation in the flow control of the flow control valve 20 using the shutoff valve device 54 and the mass flow rate detection means 8. The control means 18 is configured to be able to control.
The shut-off valve devices 52 and 54 are also used when it is necessary to completely shut off the gas flowing to the semiconductor manufacturing apparatus side.
The mass flow control device 50 configured in this way is accommodated in a size that satisfies the above-mentioned SEMI standard (total length 99.5 mm × width 38.15 mm), for example.

Next, the configuration of the shut-off valve devices 52 and 54 will be described in detail. Here, since the two shut-off valve devices 52 and 54 have the same configuration, the following explanation will be made by taking the shut-off valve device 54 on the downstream side as an example.
As shown in FIG. 2, the downstream shut-off valve device 54 includes a valve chamber 36 in which gas temporarily accumulates, an inflow path 34 through which a gas as a control fluid flows, and a valve chamber 36. And an outflow passage 40 through which gas flows out.
The upper end portion of the inflow path 34 is either directly communicated with the flow rate control valve 20 or forms another flow path, and as a result, the inflow port which is the lower end portion of the inflow path 34 Is the valve port 42 of the shut-off valve device 54. A ring-shaped valve seat 44 made of, for example, fluororesin (PTFE, PCTFE, etc.) is provided at the end (the lower end in the figure) of the valve port 42 so as to slightly protrude in the distal direction. The valve seat 44 may be a metal valve seat by processing the valve opening 42 portion.

The outflow passage 40 extends from an outflow port 78 provided so as to face the valve chamber 36, and its tip is configured as a fluid outlet 6B (see FIG. 1). The inflow path 34, the outflow path 40, and the valve chamber 36 can be formed in the valve block body 80 by cutting a lump made of, for example, stainless steel to process holes and recesses. The valve block body 80 is used in common with the flow rate control valve 20, and a shutoff valve device 54 is integrally provided in the mass flow rate control body 50. The valve chamber 36 is provided so as to be located at the innermost part of the mounting recess 74, and the lower portion of the valve chamber 36 is hermetically partitioned by a metal diaphragm valve body 38 that can be bent.

  A pressing means 82 for pressing the diaphragm valve body 38 to open and close the valve port 42 is provided on the opposite side of the diaphragm valve body 38 from the valve chamber 36. The pressing means 82 is divided by the actuator plate 84 and is supplied and discharged with an actuator plate 84 made of an elastic body disposed on the opposite side of the valve chamber 36 so as to face the diaphragm valve body 38. The operation chamber 86 and an operation gas supply / discharge mechanism 88 that supplies and discharges operation gas into and from the operation chamber 86 are mainly configured.

Specifically, first, the diaphragm valve body 38 is made of a bendable metal plate having a thickness of, for example, about 0.1 mm, and has a curved cross section and is formed in an arc shape. The diameter of the diaphragm valve body 38 is set to about 22 mm, for example. The diaphragm valve body 38 is positioned at the innermost part of the mounting recess 74, and the periphery thereof is hermetically pressed by, for example, a stainless steel diaphragm press 90 formed in a ring shape. On the surface of the diaphragm retainer 90 opposite to the surface in contact with the diaphragm valve body 38, a plurality of strips, for example, two strips, with a triangular cross section are provided along the circumferential direction. The actuator plate 84 is pressed here to enhance the sealing performance of this portion.

The actuator plate 84 is made of, for example, a disc-shaped elastic body having a thickness of about 0.4 mm, and an engagement protrusion is formed in a ring shape on the periphery thereof. As this elastic body, natural rubber or synthetic rubber can be used. For example, ethylene propylene rubber, butyl rubber, urethane rubber, silicone rubber, chlorosulfonated rubber, chlorinated polyethylene rubber, acrylic rubber, or the like can be used.
A pressing projection 92 is interposed between the central portion of the actuator plate 84 and the central portion of the diaphragm valve body 38. In the illustrated example, the pressing projection 92 is formed in a button shape as a disc-shaped projection made of brass or stainless steel and having a diameter of about 10 mm, and is attached and fixed to the actuator plate 84 side.

  Specifically, a projection screw 94 is provided at the center of the pressing projection 92, and the projection screw 94 passes through the center of the actuator plate 84 and has a screw hole at the center from the opposite side. The pressing protrusion 92 is attached and fixed by tightening the protrusion screw 94 with a button holder 96 as a guide protrusion member. On the surface where the pressing projection 92 contacts the actuator plate 84, a plurality of strips having a triangular cross section, for example, two seal grooves, are formed in a ring shape along the circumferential direction. The sealability of this part is improved.

  The peripheral portion of the actuator plate 84 thus formed is pressed by a ring-shaped plate pressing member 98 made of, for example, stainless steel. At this time, the plate holding member 98 is formed with a fitting recess 98A for fitting the engaging projection 84A of the actuator plate 84, and the hemispherical tip of the engaging projection 84A when assembled and mounted. By crushing the part, the sealability of this part can be maintained high.

  The working gas supply / discharge mechanism 88 is mainly constituted by an electromagnetic valve 102 and a cylindrical casing 104 covering the periphery thereof. Here, for example, a three-way valve type electromagnetic valve is provided as the electromagnetic valve 102 accommodated in the casing 104, and the three-way valve body 108 can be driven by the electromagnetic coil 106. Here, the first gas port of the three-way valve body 108 communicates with the inside of the working chamber 86 through a flow path 108 A formed in the casing 104, and the second outlet is a flow formed in the casing 104. The working gas inlet 76 (see FIG. 2) is communicated via the path 108B, and the third gas port is communicated to the atmosphere side via the channel 108C. Here, the power of the electromagnetic valve 102 is supplied from the control means 18, and energization / non-energization is controlled by the control means 18. That is, at the time of non-energization, the valve body 108 is pressed by the means of the spring 130 in the direction of closing the opening portion of the flow path 108B to be closed. At this time, the flow path 108 </ b> A and the flow path 108 </ b> C are in communication with each other, and the working gas does not flow into the working chamber 86. On the other hand, when energized, the valve element 108 moves in a direction to push back the spring 130 by the electromagnetic force generated by the electromagnetic valve 102, and is pressed in the direction to close the opening of the flow path 108C to be closed. At this time, the flow path 108 </ b> A and the flow path 108 </ b> B are communicated, and the working gas flows into the working chamber 86.

A male screw 110 is formed on the outer periphery of the casing 104. The male screw 112 is screwed into a female screw 112 provided at the tip of the inner wall surface of the mounting recess 74, and the casing 104 is tightened toward the back. Can be attached and fixed by pressing toward the valve chamber 36 side.
Further, a seal member 114 made of, for example, an O-ring is provided between the inner wall of the mounting recess 74 and the casing 104 to maintain airtightness. In addition, a seal member 116 made of an O-ring or the like is provided between the casing 104 and the electromagnetic valve 102 provided on the inner side thereof to maintain airtightness. Further, the lid member 120 that covers the three-way valve body 108 of the solenoid valve 102 is also provided with a seal member 118 made of an O-ring or the like between the solenoid valve 102 and the airtightness of this portion is maintained. It is like that.

Thereby, a partition wall on the opposite side of the working chamber 86 is formed by the upper end surface of the casing 104, and the working gas is supplied into the working chamber 86 through the flow path 108A as necessary. By switching the three-way valve body 108, the working gas in the working chamber 86 can be opened to the atmosphere via the flow path 108C.

Next, the first control mode of the mass flow control device of the present invention configured as described above and the operation of the shut-off valve device will be described. The first control mode here means a control mode in a so-called normal state.
The control means 18 of the mass flow control device 50 controls the flow rate control so that the flow rate indicated by the flow rate setting signal S0 input from the outside such as a host computer and the flow rate indicated by the flow rate signal S1 coincide with each other. For example, the valve opening degree of the valve 20 is continuously controlled by the PID control method. As a result, the processing gas having the required mass flow rate is supplied to the downstream semiconductor manufacturing apparatus or the like.

  Here, when the processing gas is flown, the uppermost shut-off valve device 52 and the most downstream shut-off valve device 54 receive the flow rate setting signal S0 from the outside and at the same time the shutoff valve operation signal S3, S4 is output and the operation is performed in the opening direction. Therefore, the gas whose flow rate is controlled by the flow control valve 20 flows through the inflow path 34 of the shutoff valve device 54 and flows into the valve chamber 36 from the valve port 42, and further flows into the outflow path 40 side through the outlet 78. To the semiconductor manufacturing apparatus from the fluid outlet 6B (see FIG. 1).

Further, depending on the operating state of the semiconductor manufacturing apparatus, which is a processing gas usage system, it is frequently necessary to completely stop the processing gas supply. In such a case, the shutoff valve device 54 provided on the most downstream side of the mass flow control device 50 is operated so as to be fully closed, and the flow of the processing gas is completely stopped.
Specifically, as described above, by operating the three-way valve type electromagnetic valve 102 of the working gas supply / exhaust mechanism 88 of the shut-off valve device 54, it is supplied at 0.4 to 0.7 MPa. The factory side working gas (specifically, working air) is introduced into the working chamber 86 through the flow path 108B, the three-way valve body 108 and the flow path 108A. When the working gas is introduced into the working chamber 86, the rubber actuator plate 86 partitioning the working chamber 86 is elastically bent and deformed in the upward direction in FIG. A force F toward the body 38 is generated.

  Here, since the central portion of the diaphragm valve body 38 and the distal end portion of the pressing projection 92 provided at the central portion of the actuator plate 84 are always in contact, the central portion of the diaphragm valve body 38 is in contact with the pressing projection 92. Will be intensively pressed. As a result, the diaphragm valve body 38 can be easily bent and deformed, seated on the valve seat 44, and the valve port 42 can be completely closed to completely block the flow of the processing gas. As a result of the experiment, the shut-off valve device 54 could be reliably opened and closed even when the pressure of the working gas supplied from the outside was 0.35 MPa.

  When the processing gas is allowed to flow again after the processing gas is shut off, as described above, the electromagnetic valve 102 is driven to move the three-way valve body 108 and the pressurized state introduced into the working chamber 86 is reached. The working gas is released to the atmosphere through the flow path 108C. As a result, the actuator plate 84 moves away from the valve seat 44 by its own elastic return force and the elastic restoring force of the diaphragm valve body 38 to return to the original position (normally open state), thereby opening the valve port 42. It will be.

  Thus, the working fluid is always supplied to the flow path 108B at 0.4 to 0.7 MPa, and when the operation signals S3 and S4 of the shutoff valves 52 and 54 are input, the three-way valve body 108 is If the flow path 108A and the working chamber 86 are filled with the working fluid, the shutoff valves 52 and 54 can be operated. Therefore, the shutoff valves 52 and 54 operate after the shutoff valve operation signals S3 and S4 are input. The time difference until is very short.

  FIG. 3 is an experimental example in which the time from when the shut-off valve operation signals S3 and S4 are input to when the shut-off valves 52 and 54 are operated is compared with the prior art. In Comparative Examples 1 to 3, the distance between the shut-off valve device and the solenoid valve mechanism is 2 m, 20 m, and 30 m, respectively, and the working gas pressure is 0.4 MPa and 0.7 MPa. The time until occlusion was compared.

  As a result, as shown in FIG. 3, the shut-off valve device integrated into the mass flow control device of the present invention operates in less than half the time compared to the conventional comparative example, and is almost the same as the shut-off valve device and the flow rate. The operation timing with the control valve mechanism was synchronized, and the overshoot phenomenon of the mass flow control device when the shut-off valve was opened could be prevented.

  Next, the second control mode will be briefly described. In a semiconductor manufacturing process using a mass flow controller, pressure fluctuations may occur due to unexpected causes or processing gas switching. When the pressure fluctuation of the processing gas supplied to the mass flow controller suddenly occurs, the accuracy of the flow control may be affected for a short time. The second control mode is provided as a control mode in which the accuracy of the flow rate control is not deteriorated even when a pressure fluctuation occurs in the gas supplied to the mass flow rate control device.

First, in the first control mode described above, the pressure detection signal S5 output from the pressure detection unit 58 is output to the control unit 18, for example, every 10 msec, stored in the control unit 18, and the amount of pressure change every 10 msec. Is monitoring. On the other hand, the control means 18 includes, for example, a valve drive signal S2 for controlling the valve opening degree of the flow rate control valve 20 for each flow rate setting signal S0 corresponding to a pressure of 0.05 MPa, and a first control mode to a second control mode. The pressure fluctuation threshold amount is stored in order to determine whether to switch to
Then, the pressure change amount is compared with the pressure fluctuation threshold amount, and when the pressure change amount is larger than the pressure fluctuation threshold amount, it is determined that the pressure fluctuation has occurred, and the first control mode to the second control mode are determined. Switch to.

In the second control mode, a valve drive signal for controlling the valve opening degree of the flow control valve 20 is calculated from the pressure detection signal S5 and the flow rate setting signal S0 before the pressure change amount exceeds the pressure fluctuation threshold amount. , Output to the flow control valve 20.
The pressure change amount and the pressure fluctuation threshold amount are continuously compared during the second control mode, and when the pressure change amount becomes smaller than the pressure fluctuation threshold amount, the second control mode is switched to the first control mode. .
As described above, since the first control mode and the second control mode are provided so as to be switched according to the pressure fluctuation of the processing gas supplied to the mass flow control device, when the pressure fluctuation of the processing gas occurs In addition, the accuracy of the process gas flow rate control is maintained.

Next, the verification operation mode will be briefly described.
When performing a verification operation for verifying whether the flow rate measurement value of the mass flow control device is correct or not, the downstream shut-off valve device 54 is opened, and the shut-off valve device 52 having the most upstream value is closed. Will be done as a state. The opening / closing operation in this case is the same as the case described above for the opening / closing operation of the shut-off valve device 54 on the downstream side.
First, the semiconductor manufacturing apparatus side is continuously evacuated, and the upstream shut-off valve device 52 is completely closed in a state where a certain amount of gas is stably flowing at a predetermined flow rate. Then, the gas that has been filled in the tank main body 68 of the verification tank unit 56 until now flows out gradually from the tank main body 68 to the downstream side, and at the end, the pressure is reduced to the base pressure by evacuation. Will do. The change in pressure at this time is measured by the pressure detecting means 58 to obtain a fluctuation characteristic, that is, a pressure drop characteristic.

Such pressure drop characteristics are acquired each time the set flow rate of the gas is changed and stored in the verification data memory 72B. The pressure drop characteristic acquired for each set flow rate is compared with each reference pressure drop characteristic acquired in advance and stored in the reference data memory 72A, and the difference is calibrated.
In the above-described shut-off valve devices 52 and 34, a case where a three-way valve type solenoid valve is used as the solenoid valve 102 has been described as an example. However, the invention is not limited to this, and a two-way valve or a four-way valve is used. The above solenoid valve may be used. When a two-way valve type solenoid valve is used, the supply and discharge of the working gas is controlled by an external control system.

  The closing operation of the shut-off valve device 54 described above is also performed when the zero point of the mass flow control device is adjusted. For example, the gas flowing through the flow control valve 20 by setting the shut-off valve device 54 to a fully closed state. The zero flow rate can be completely zeroed, and zero point calibration can be performed with the detected value of the flow rate at this time.

Moreover, it can be set as the mass flow control apparatus 51 shown in FIG. 4 in this invention. The same components as those shown in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.
The mass flow control device 51 shown in FIG. 4 is provided with a valve block 81 so as to satisfy the above SEMI standard (total length 105 mm × width 28.6 mm). The cutoff valve 52 can be provided below the valve block 81 by the length of the entire length.
Accordingly, the fluid inlet 6A of the mass flow control device 51 can be formed with a smaller number of turns than that of the mass flow control device shown in FIG. Therefore, the pressure loss of the processing gas can be minimized.

Next, a gas supply unit using the mass flow controller of the present invention will be described with reference to FIG. The gas supply unit 150 shown in FIG. 5 has a manual shut-off valve S and a mass flow controller 50 arranged on the base B, and the manual shut-off valve S and the mass flow controller 50 are connected to a V (not shown) V. Are connected by a flow path block V2 having a flow path, and joint blocks V1 and V7 are disposed on the upstream side and the downstream side.
Compared with the conventional gas supply unit 151 shown in FIG. 6, since the mass flow control device 50 includes the shut-off valve devices 52 and 54, the pneumatically driven shut-off valves A1 and A2 are not required, and pressure detecting means is provided. At the same time, when the pressure fluctuation of the processing gas occurs, the control is performed by switching between the first control mode and the second control mode, so that the pressure control valve R and the pressure sensor T are not required. Further, the flow path blocks V3 to V6 for connecting them are not required.
Therefore, the gas supply unit having the same function can be made very compact and not only can be supplied at low cost, but also the number of connection points can be reduced, so that the possibility of gas leakage can be kept extremely low.

It is one Example of the mass flow control apparatus concerning embodiment of this invention. It is an enlarged view which shows the cutoff valve apparatus of the mass flow control apparatus concerning embodiment of this invention. It is an implementation comparative example of the present invention and the prior art. It is another Example of the mass flow control apparatus concerning embodiment of this invention. It is one Example of the gas supply unit concerning embodiment of this invention. It is a conventional gas supply unit.

Explanation of symbols

6A: Fluid inlet, 6B: Fluid outlet, 8: Mass flow rate detection means, 10: Flow rate control valve mechanism, 12: Bypass pipe, 14: Sensor pipe, 16: Sensor circuit, 18: Control means, 20: Flow rate control valve, 26: Actuator, 28: Valve drive circuit,
34: inflow path, 36: valve chamber, 38: diaphragm valve body, 40: outflow path, 42: valve opening, 44: valve seat,
50, 51: Mass flow control device, 52, 54: Shut-off valve device, 56: Test tank, 58: Pressure detection means, 62, 64: Working gas supply / exhaust port, 68: Tank body, 70: Temperature detection means ,
74: recess, 78: outlet, 80, 81: valve block body, 82: pressing means, 84: actuator plate, 84A: engagement protrusion, 86: working chamber, 88: working gas supply / discharge mechanism, 90: diaphragm presser , 92: pressing protrusion, 94: protrusion screw, 96: button holder, 98: plate pressing member, 98A: fitting recess,
102: Solenoid valve (solenoid valve mechanism), 104: casing, 106: electromagnetic coil, 108: three-way valve body,
108A, 108B, 108C: flow path, 110: male screw, 112: female screw, 114, 116, 118: seal member, 120: lid member, 130: spring,
S0: flow rate setting signal, S1: flow rate signal, S2: valve drive signal, S3, S4: shutoff valve operation signal (solenoid valve drive signal), S5: pressure detection signal,
150, 151: gas supply unit,
M: Mass flow controller, S: Manual shutoff valve, R: Pressure control valve, T: Pressure sensor, A1, A2: Pneumatic drive shutoff valve, V1, V7: Joint block, V2, V3, V4, V5, V6: Flow Road block,

Claims (4)

At least a flow rate control valve mechanism for controlling the mass flow rate by changing the valve opening degree according to the valve drive signal, and a flow rate control for outputting the valve drive signal to the flow rate control valve mechanism based on a flow rate setting signal input from the outside In a mass flow control device comprising a valve control means,
A shut-off valve mechanism that is opened and closed by supplying and exhausting working gas to the upstream side and / or the downstream side of the flow control valve mechanism, and a working chamber in which the working gas in the shut-off valve mechanism is supplied and discharged; The shutoff valve mechanism and the solenoid valve mechanism are integrally provided in the valve block body of the mass flow control device so as to directly communicate with the flow path of the solenoid valve mechanism for supplying and exhausting the working gas,
The shut-off valve mechanism includes a valve chamber provided in a valve block body of the mass flow control device, an inflow passage through which fluid flows into the valve chamber, an outflow passage through which fluid flows out from the valve chamber, and the inflow A valve seat provided at a valve port comprising either one of an inflow path and an outflow path of the outflow path, the valve seat being disposed so as to face the valve seat, and the valve seat A metal diaphragm valve body that abuts against the valve port and a pressing means for pressing the diaphragm valve body,
It said pressing means includes an actuator plate made of arranged elastic body so as to face the diaphragm valve element on the opposite side of the valve chamber, is always the tip is interposed between the diaphragm valve member and the actuator plate A pressing projection that contacts the central portion of the diaphragm valve body, and a working chamber that is partitioned by the actuator plate and into which working gas is supplied and discharged,
The flow rate control valve control means outputs a solenoid valve drive signal for operating the solenoid valve mechanism, and synchronizes the valve drive signal and the solenoid valve drive signal.   The solenoid valve mechanism includes a three-way valve body, a three-way valve chamber in which the three-way valve body is housed, a working gas input port that introduces working gas into the three-way valve chamber, and a working gas output port that communicates with the working chamber. And a three-way valve first valve seat provided around the communication between the three-way valve chamber and the working gas input port, and an exhaust port provided opposite to the three-way valve first valve seat in the three-way valve chamber And a three-way valve second valve seat provided around the communication between the three-way valve chamber and the exhaust port, and an electromagnetic coil for operating the three-way valve body when an operating voltage is applied. The mass flow control device according to claim 1. A flow rate detection means for detecting a flow rate and outputting a flow rate signal and a pressure detection means for detecting the pressure of the fluid and outputting a pressure detection signal are provided in the flow path for flowing the fluid,
The flow rate control valve control means includes a first control mode for controlling the flow rate based on the flow rate signal and the flow rate setting signal without using the pressure detection signal, and a pressure change amount obtained from the pressure detection signal. The mass flow control device according to claim 1, wherein the mass flow control device is configured to selectively switch between a second control mode in which a flow rate is controlled based on the flow rate setting signal.   The gas supply unit in which a plurality of fluid control devices connected via a plurality of flow path blocks are mounted on the upper surface of the base plate, wherein at least one of the fluid control devices is according to any one of claims 1 to 3. A gas supply unit which is a mass flow controller.

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