JP2001147722A - Gas flow rate controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas flow rate controller for accurately and safely supplying gas. SOLUTION: This gas flow rate controller consists of a pneumatically driven value A for controlling a gas flow rate, by changing the aperture of a gas passage according to driving air pressure, a gas flow rate measuring instrument B having a gas rate measuring part, consisting of the combination of a sonic nozzle and a pressure sensor and a storage/operation part for arithmetically processing a signal sent from the gas flow rate measuring part and sending a control signal, a pneumatically driven stop value C, and a plate D, detachably fitting the pneumatically driven value A, the gas flow rate measuring instrument B and the stop value C on its one face and piercing the gas passage connecting these parts A to C in this order. The measuring instrument B detects and operates the gas flow rate of gas flowing into the gas passage of the plate D and sends a control signal to an external air pressure controller and the aperture of the value A is adjusted by driven air sent from the air pressure controller, on the basis of the sent data to control the gas flow rate of gas flowing into the gas passage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas flow control device using a pressure measuring device including a sonic nozzle and a pressure sensor. This gas flow control device is particularly suitable for controlling the flow rate of a source gas in semiconductor manufacturing.

[0002]

2. Description of the Related Art Conventionally, in various industries, gas flow rate control is performed. In particular, in semiconductor manufacturing, various source gases need to be supplied under accurate sequence control, and various gas flow controllers are used for this purpose.

FIG. 3A is a flow chart showing the configuration of a gas flow control device conventionally used in a general gas line, and FIG. 3B shows a control device configured according to the above flow diagram. It is.

The gas supplied through the gas line 80 is controlled to a substantially constant pressure by a regulator 84 through a manual opening / closing valve 82, and the pressure is displayed by a pressure sensor 86. The gas whose pressure is controlled is then sent to a mass flow controller 92 (hereinafter, MFC) through a filter 88 and a stop valve 90, whereby the gas flow rate is controlled. The gas whose gas flow rate has been controlled is then supplied to a desired location through a stop valve 94.

[0005] The filter 88 removes fine particles mixed in the gas line 80, and is provided for the purpose of preventing the mixed fine particles from flowing downstream and preventing the MFC 92 from being damaged. .

Reference numeral 96 denotes a branch line for introducing a purge gas, which is connected to the upstream side of the MFC 92. 98, 10
Reference numeral 0 denotes a check valve and a stop valve interposed in the branch line 96, respectively.

[0007] A branch line 102 is also connected to the downstream side of the MFC 92. 104 is a stop valve interposed in the branch line.

As shown in FIG. 3 (B), the control device constructed in accordance with the above flow chart is configured such that each component can be attached and detached from one direction (the direction of arrow X in this figure). Such a panel is generally called a surface mount type gas panel.

Of the above components, the regulator 84
Is provided to secure the operation stability of the MFC 92 by keeping the gas supply pressure constant and to prevent the gas from flowing back to the upstream side when the pressure rises downstream of the regulator 84. ing.

The valves 9 provided on both sides of the MFC 92
The reference numerals 0 and 94 are provided for the purpose of preventing the control valve built in the MFC 92 from being completely closed, and having to frequently replace the MFC 92, and preventing outside air from entering the line at the time of the replacement. Has been established.

Although not shown in the above flow chart, a branch line may be further provided upstream and downstream of the MFC 92 for introducing a gas at the time of purging and performing vacuum evacuation.

As apparent from the above description, the conventional gas flow control device is mainly composed of the MFC, and is composed of components for protecting the MFC and components for ensuring safety in the event of an abnormality. Therefore, it cannot always be said that the gas flow control apparatus meets the original purpose of accurately and safely supplying gas at a required flow rate when needed, which is the original purpose of the gas flow control apparatus. In order to manufacture a gas flow control device that meets the above-mentioned object, it is necessary to add further components to make the configuration complicated, and in this case, it becomes expensive.

Further, the components are manually (regulator),
It is driven by various powers such as pneumatic pressure (open / close valve) and electric power (MFC), so that automatic control is difficult.

Further, it is also difficult to provide the current self-diagnosis function of the apparatus (for example, a valve seat leak or a change in the actual flow rate of the MFC).

Further, in the conventional gas flow control device, the driving air pressure of the open / close valve used is not monitored,
For this reason, the exact opening / closing timing is not known. For this reason, a shift in the scheduled timing between the valves occurs,
In some cases, backflow of gas may occur.

Further, the conventional gas flow control device is MF
C has problems such as poor replacement characteristics and response speed, which are the essential problems of C. In addition, MFC uses a heating coil for the electric valve and the flow rate sensing part, so it cannot be used as an intrinsically safe explosion-proof structure. There's a problem.

[0017]

The present inventors have made various studies to solve the above problems. As a result, it is known that the above problem can be solved by configuring a gas flow control device using a gas flow measurement device in which a pneumatic drive valve, a sonic nozzle, and a pressure sensor are combined, and a plate having a gas flow path formed therein. Thus, the present invention has been completed.

Accordingly, it is an object of the present invention to provide a gas flow control device which solves the above problems.

[0019]

The present invention to achieve the above object is as described below.

[1] (A) Pneumatic drive valve for controlling gas flow rate by changing opening of gas flow path in accordance with drive air pressure, and (B) Gas flow rate measurement consisting of a combination of sonic nozzle and pressure sensor A gas flow rate measuring device having a memory section for taking in and processing a signal transmitted by the gas flow rate measuring section and transmitting a control signal; (C) a pneumatic drive stop valve; and (D) a pneumatic drive. A valve, a gas flow meter, and a pneumatically driven stop valve are detachably mounted on one side thereof, and a plate provided with a gas flow path connecting these in this order,
The flow rate of the gas flowing through the gas flow path formed in the plate is detected and calculated by a gas flow meter, and a control signal is sent to an external pneumatic controller. A gas flow control device that controls a gas flow rate flowing through a gas flow path formed in the plate by adjusting an opening degree of a valve.

[2] The gas flow control device according to [1], wherein the shape of the mounting surface of the pneumatically driven valve, the gas flow measuring device, and the pneumatically driven stop valve to the plate is standardized.

[3] The gas flow control device according to the above [1], wherein the storage operation unit stores flow calibration characteristics for each type of gas.

[4] The gas flow control device according to the above [1], wherein the memory operation unit has a leak judging function of the pneumatically driven valve and the pneumatically driven stop valve.

[5] The storage operation unit is a sonic nozzle,
The gas flow control device according to the above [1], further comprising a function of determining a closed state of a downstream portion of the sonic nozzle.

[6] The gas flow control device according to [1], wherein a pneumatic drive valve is used as the pneumatic stop valve.

Hereinafter, the present invention will be described in detail with reference to the drawings.

[0027]

FIG. 1 shows an example of a surface-mounted gas panel 200 incorporating a gas flow control device of the present invention. The configuration of the present invention is a component surrounded by a two-dot chain line Y.

In FIG. 1, reference numeral 2 denotes a cross section of the plate. The plate 2 is a thick plate made of metal such as stainless steel or aluminum. The plate 2 has substantially U-shaped gas flow paths 6 perforated at predetermined intervals from one surface 4 (the upper surface in the figure) of the plate 2. The upper end of the U-shaped gas flow path 6 forms a substantially circular communication hole 8 on the upper surface of the plate. Reference numeral 10 denotes a pneumatically driven stop valve mounted on the upper surface of the plate 2, which is detachable so that the communication hole 8 of the gas flow path 6 formed in the plate 2 is connected to the gas flow path of the stop valve 10. Attached to the plate 2. As a result, the gas flowing through the gas flow path 6 is sent to the valve 10 through the communication hole 8a, and then returned to the gas flow path 6 from the communication hole 8b through the valve 10.

Reference numerals 7a and 7b denote purge gas introduction paths, respectively, which are connected to the flow path 6 via a stop valve 10 and a stop valve 18 described later.

Reference numeral 12 denotes a pneumatic drive valve connected to the valve 10, reference numeral 14 denotes a gas flow rate measuring device, reference numerals 16 and 18 denote gas drive stop valves, both of which are sequentially connected at predetermined intervals on the plate 2. And these valves 12, 1
Each of the flow paths of the gas flowmeters 6 and 18 and the gas flow meter 14 is connected to each communication hole of the U-shaped flow path 6 in the same manner as the valve 10. As a result, the gas sent from the upstream side 6a of the gas flow path 6 to the gas flow path 6 flows out of the downstream side 6b of the gas flow path 6 sequentially through the valve and the measuring instrument.

The bottom surfaces of the valves 10, 12, 16, 18 and the measuring instrument 14 are all formed in the same shape.
Therefore, they are regularly arranged in the same direction on the plate 2 with a predetermined interval and the same bottom shape.

The pneumatic drive valve 12 is a pneumatic drive control valve that can be adjusted to an arbitrary opening by a fluid control system. Examples of this include controlling the gas flow rate by adjusting the opening degree of the gas flow path by driving the metal diaphragm with driving air pressure,
Such valves are known. Particularly preferred pneumatically driven valves include the valves described in JP-A-11-101352 designed for such purpose.

FIG. 2 is an enlarged view of the gas flow meter 14. In FIG. 2, reference numeral 60 denotes a gas inflow pipe, and the gas flowing into the gas flow meter 14 through the U-shaped gas flow path 6 is sent to the pressure measurement chamber 62 through the inflow pipe 60. The pressure sensor 64 measures the inflow gas pressure. 70
Is a storage operation processing unit described later, and the measurement data of the pressure sensor is operated here.

Thereafter, the gas is sent from the gas outlet pipe 68 through the sonic nozzle 66 to the U-shaped gas flow path 6.

In FIG. 1, reference numeral 20 denotes a pneumatic controller provided with a storage operation processing unit, which receives a signal sent from the storage operation processing unit 70 of the gas flow rate measuring device 14 and receives driving air through a driving air line 22 to drive the pneumatic driving valve 12. Send to

As the pneumatic controller 20, a commercially available electropneumatic regulator or a gas controller using a proportional solenoid can be used.

A control unit 24 transmits a control signal to the pneumatic controller 20 according to a predetermined sequence or manually, whereby the pressurized air is supplied to the driving air lines 26 and 2.
8 and 30, respectively, to control the opening and closing of the valves 10, 16 and 18.

Next, a case where the gas flow rate is controlled using the gas flow rate control device will be described.

The gas flow meter 6 sends the gas
Sent into the pressure measuring chamber 62 shown in FIG. 2 as described above, where the pressure is measured by the pressure sensor 64.

The pressure signal measured by the pressure sensor 64 is sent to a storage operation processing unit 70, where a predetermined operation such as a comparison operation is performed.

The calculation result by the storage calculation processing unit 70 is converted into an electric signal, and is converted into an electric signal.
Is transmitted to

The driving air pressurized through the driving air line 22 is supplied to the pneumatic driving valve 12 by the pneumatic controller 20 receiving the electric signal. By the supply of the driving air, the opening of the valve 12 is adjusted so as to have a predetermined desired flow rate. When the flow rate is smaller than the set value, the operation of increasing the air pressure is performed, and when the flow rate is larger, the operation of decreasing the air pressure is automatically performed. As a result, the flow rate of the gas flowing out of the gas flow control device is maintained at a predetermined flow rate.

Next, a case where self-diagnosis is performed using the above-described device will be described.

(1) Diagnosis of Seat Leak The pneumatic valve 12 has a complete closing function. That is, it is incorporated in the gas flow control device while guaranteeing that there is no sheet leak. However, when foreign matter adheres to the seat portion (valve seat) of the drive valve, the valve breaks down, or the life of the valve comes, the drive valve may cause a seat leak. The determination of seat leak in this case is
This is performed as follows.

First, the valves 12 and 16 on both sides of the gas flow meter 14 are closed. Next, the output of the pressure sensor 64 is observed. If there is a pressure increase, it can be determined that the upstream valve 12 has a leak. When the output of the sensor 64 indicates a pressure drop, it can be determined that the downstream valve 16 has a leak.

(2) State Diagnosis of Sonic Nozzle and Its Downstream Side When a foreign substance such as a particle adheres to the sonic nozzle 66 or the downstream side of the sonic nozzle 66 approaches a closed state, the sonic state of the gas passing through the nozzle is reduced. It cannot be maintained and the actual flow rate changes. The following operation is performed to periodically diagnose this condition.

First, the pneumatic drive valve 12 on the upstream side of the gas flow meter 14 is closed, and a pressure drop state (initial characteristic) with respect to time is measured by the pressure sensor 64 and recorded in the pneumatic controller 20.

Next, after the elapse of a desired period, the pressure drop state is measured in the same manner. The state of the device can be determined by comparing the characteristics after the passage with the initial characteristics.

When the descent characteristic is a descent in the sonic range, the nozzle is diagnosed, and when the descent characteristic is in a subsonic range, the flow path on the downstream side is diagnosed as blocked. Further, it can also be used as a judgment data of the maintenance time according to the degree of the change.

(3) Calibration Characteristics The CF (now version factor) of the gas is stored in the storage arithmetic processing unit 70 of the gas flow meter according to the type of gas, and this data is used when the gas type is changed. .
The correction of the gas flow rate with respect to the temperature can be similarly performed.

In the above description, the pressure sensor 6
The detection signal of No. 4 is compared with the set value by the storage arithmetic processing unit 70 and transmitted to the pneumatic controller 20. However, the present invention is not limited to this, and the comparing process may be performed in the pneumatic controller 20. Further, a purge branch line may be provided between the gas flow rate measuring device 14 and the pneumatic drive valve 12, and a filter or the like may be provided in a flow path as appropriate. For example, a commercially available gasket-like filter may be attached to the joint on the upstream side of the gas flow control device.

Further, the gas flow path in the plate is formed in a substantially U-shape. However, the present invention is not limited to this. The gas flow path can be formed in any shape such as a V-shape or an arc shape.

[0053]

According to the present invention, the above-described configuration provides the following effects. (1) In the surface mount type gas panel, since the bottom shapes of all the components are the same, the flow path can be easily designed with the plate. For this reason, it is possible to easily cope with the addition or modification of the line. (2) Since the gas flow rate is controlled by the pneumatic drive valve and the gas flow rate measuring device using the sonic nozzle, the configuration of the device is simplified and the manufacturing cost is reduced. (3) An intrinsically safe explosion-proof device can be constructed by using air pressure for driving the valve. (4) The pneumatically driven valve can be used as a pneumatically driven stop valve. In this case, the relationship between the opening degree of the pneumatically driven valve and the air pressure is obtained and stored in advance, so that the opening degree of the valve can be arbitrarily adjusted. As a result, it is possible to avoid a sudden pressure rise when introducing the purge gas, reduce the pressure impact on the pressure sensor of the gas flow meter, and at the time of venting, the gas flows out of the vacuum pump or the exclusion device beyond the allowable limit of its processing capacity. It can be controlled so as not to happen. In addition, since the valve can be closed softly, damage to the seat portion of the valve can be minimized, and the generation of particles can be suppressed to a minimum. (5) Since the gas flow rate control device can have a self-diagnosis function, in this case, it can be confirmed in advance that the process conditions such as the actual gas flow rate and the complete closing of the valve have not changed. It is also possible to determine the maintenance time,
Accidents such as sudden process inoperability can be minimized. (6) The gas flow control device of the present invention has many gas types that can be controlled, and the gas flow range can be changed only by replacing the gas flow measurement unit.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing the configuration of an embodiment of the present invention.

FIG. 2 is a schematic view showing an example of the structure of a gas flow meter.

FIG. 3 (A) shows an example of a conventional gas flow control device.
Is a flow diagram, and (B) is a schematic configuration diagram.

[Explanation of symbols]

 2 plate 4 one side 6 gas flow path 6a upstream 6b downstream 7a, 7b purge gas introduction path 8 communication hole 10, 16, 18 stop valve 12 pneumatic drive valve 14 gas flow meter 20 pneumatic controller 22 drive air line 24 control unit 60 Gas inflow pipe 62 Pressure measurement chamber 64 Pressure sensor 66 Sonic nozzle 68 Gas outflow pipe 70 Memory operation processing unit 80 Gas line 82 On / off valve 84 Regulator 86 Pressure sensor 88 Filter 90, 94, 100 Stop valve 92 Mass flow controller 96 Branch line 98 Reverse Stop valve 100, 104 Stop valve 200 Gas panel

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[Procedure amendment]

[Submission date] November 24, 1999 (1999.11.
24)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

[Title of the Invention] Gas flow control device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nara ▲ Saki ▼ Katsumi 5-36-5 Kamata, Ota-ku, Tokyo 10th Sakairi Building 5F AC E Co., Ltd. (72) Inventor Toshikatsu Meguro Miyagi 5-2, Kameoka, Ohira, Ohira-mura, Kurokawa-gun, F-term F-term (reference) in Oyama Plant of Motoyama Works

Claims (6)

[Claims] 1. A gas flow measuring unit comprising a combination of (A) a pneumatic drive valve for controlling a gas flow rate by changing an opening degree of a gas flow path according to a drive air pressure, and (B) a sonic nozzle and a pressure sensor. A gas flow measuring device having a storage operation unit that takes in and processes a signal sent by the gas flow measurement unit and sends out a control signal; (C) a pneumatic drive stop valve; and (D) the pneumatic drive valve. When,
A gas flow meter and a pneumatically driven stop valve are detachably mounted on one side thereof, and a plate is provided with a gas flow path that connects these in this order, and flows through the gas flow path formed in the plate. The flow rate of the gas is detected and calculated by a gas flow meter, and a control signal is sent to an external pneumatic controller.Based on this data, the opening degree of the pneumatic drive valve is adjusted by the driving air sent out by the pneumatic controller. A gas flow control device that controls a gas flow rate flowing through a gas flow path formed in a gas flow path. 2. The gas flow control device according to claim 1, wherein the shape of the mounting surface of the pneumatically driven valve, the gas flow measuring device, and the pneumatically driven stop valve to the plate is standardized. 3. The gas flow control device according to claim 1, wherein the storage operation unit stores flow calibration characteristics for each type of gas. 4. The gas flow control device according to claim 1, wherein the storage operation unit has a function of determining leak of the pneumatically driven valve and the pneumatically driven stop valve. 5. The gas flow control device according to claim 1, wherein the storage operation unit has a function of determining a closed state of the sonic nozzle and a downstream portion of the sonic nozzle. 6. The gas flow control device according to claim 1, wherein a pneumatic drive valve is used as the pneumatic stop valve.