JPS62137473A - Mass flow control valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a control valve for controlling the flow rate of a fluid, and particularly to a mass flow control valve that prevents foreign matter from entering the fluid.

[Background technology]

When manufacturing semiconductor devices, it is necessary to supply processing gas to various processing equipment at a controlled flow rate, and mass 7o-:I trol pulp is usually installed in the gas supply system of this type of equipment. Il. Generally, this type of control valve consists of a mass flow meter installed in a part of the gas flow path to measure the flow rate, and a control valve that adjusts the opening degree of the gas flow path based on the measured value of this mass flow meter. are doing.

As shown in FIG. 3, a conventional control valve of this type includes a cylindrical valve cylinder 30, and a valve body 31 and a valve seat body 32 that are fitted on the upper and lower sides of the valve cylinder 30, respectively. have,
The valve body 31 and the valve seat body 32 are slidably brought into close contact with each other by a temporary spring 34 inserted between the plug 33 and a suitable elastic force. A first passage 35 is provided in the valve seat body 32.
and a second passage 36 are opened, and both passages 3
5.36 is the inlet port 37 at the joint surface with the valve body 31
and is open as an exit boat 38.

Further, as shown in FIG. 4, a valve passage 39 extending in the circumferential direction is formed in the joint surface of the valve body 31, the width of which gradually decreases from the center to the periphery. Further, a valve stem 40 is connected to the upper surface of the valve body 31, and a pulse motor 4 is connected to the valve stem 40.
1, the valve stem 40 is configured to rotate in rotation.

According to this configuration, when the valve body 31 is rotated via the valve stem 40, the rotation angle of the valve body 31 with respect to the valve seat body 32 is changed, and the position of the valve passage 39 facing the outlet port 38 of the valve seat body 32 is changed. be changed. Therefore, the degree of opening of the exit boat 38 is changed, and the flow rate of gas flowing through these passages is controlled.

However, in this configuration, in order to control the flow rate, the valve body 31 must be rotated relative to the valve seat body 32, so frictional force acts on the joint surface between the two, causing wear. A problem that wear powder becomes foreign matter and gets mixed into the gas is likely to occur. Particularly, when foreign matter is mixed into the processing gas for manufacturing semiconductor devices, it causes a decrease in the manufacturing yield of semiconductor devices. In addition, the valve body 31 and the valve seat body 32
Because it is necessary to rotate relative to each other while in surface contact,
Contact resistance on both surfaces increases the rotational operation force, which tends to cause problems such as difficulty in smooth operation.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a mass flow control valve that prevents the generation of foreign matter in the control valve and reduces the operating force of the valve to enable smooth operation.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, the valve body is configured to be movable in the axial direction, and the actual opening degree of the passage is adjusted by changing the amount of clearance between the valve body and the valve seat body as the valve body moves in the axial direction, thereby controlling the operation of the valve body. This is intended to facilitate smooth operation and prevent the generation of foreign matter.

〔Example〕

FIG. 1 is an overall cross-sectional configuration diagram of an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA in FIG. 1.

This mass flow control valve includes a main flow path 1 formed in a cylindrical shape, and bulges 2a and 2b are formed near both ends of the main flow path 1, respectively, and a detour path 3 made of a small diameter cylinder is provided between these. is formed. A flow rate limiting element 4 is inserted in the main flow path 1. Further, a thermal mass flow meter 5 having self-heating resistors 6a and 6b is disposed approximately in the center of the detour 3, and its resistance value changes depending on the gas flow rate flowing through the detour 3. . These self-heating resistors 6a and 6b constitute a bridge circuit together with other resistors 6c and 6d, and are connected to a voltmeter 7. In the figure,
8 is a cover.

A mass flow control valve 9 is disposed downstream of the main flow path 1. This mass flow control valve 9 has a cylindrical valve barrel 10 connected to the main flow path 1 and oriented in the vertical direction, and a valve body 11 and a valve seat body 12 are installed inside the valve barrel 10 above and below. ing. The valve seat body 1 has a first passage 15 with an inlet port 17 opened at approximately the center of the upper surface.
and a second passageway 16 having an outlet port 18 at the end of the top surface.
and are fixedly provided within the valve cylinder lO. Further, the valve body 11 has a flat joint surface with the valve seat body 1, and is installed inside the valve cylinder 10 so as to be movable in the vertical direction, that is, in the axial direction. And this valve body 1
A screw 19 that protrudes upward is integrally attached to the top surface of 1. This screw 19 is prevented from rotating by a key 20 provided on a fixed frame 23 of the valve, and the threaded portion at its upper end is screwed into a female threaded portion of a rotating shaft 22 of a pano smoke 21. In addition, in the figure, 24 and 25 are rings for sealing.

Next, the effect will be explained.

A part of the gas flowing through the main channel 1 is separated into the bulge 2a, passes through the detour 3, and returns to the main channel 1 through the bulge 2b. The self-heating resistors 5a and 5b attached to the detour 3 are cooled by the gas flow flowing through the detour 3, and their resistance values are changed depending on the degree of cooling.

The degree of this resistance change is measured by the bridge circuit and the voltmeter 7-, and based on this, the flow rate in the main flow path 1 can be measured. A signal of this measurement value is sent to the mass flow control valve 9.

Then, the control valve 9 operates the pulse motor 2I based on this measurement value signal, thereby causing the valve body 1 to operate.
1 on the valve seat body 12. 2nd each passage 1
5. Adjust the opening degree of 16.

That is, for example, when increasing the opening degree to increase the flow rate, the pulse motor 21 rotates and moves the screw 19 upward via the rotating shaft 22. For this reason, the valve body 11 integrated with the screw 19 is gradually moved upward within the valve cylinder 10, increasing the distance between the contact surface with the valve seat body 12. As a result, the first. The substantial opening degree of the second passage 15.16 increases;
Increase the flow rate of gas flowing through them. Conversely, when the valve body 11 approaches the valve seat body 12 and the distance between the joint surfaces of the two becomes smaller, the first. The substantial opening degree of the second ii11 passage 15.16 is reduced, and the gas flow rate is reduced.

Therefore, in this control valve 9, the valve body 11
The valve body 1
1 and the valve seat body 12 will not wear out, and no foreign matter will be generated. Although the valve body 11 slides on the seal ring 24 by axial movement, no wear occurs in this portion.

In addition, in this control valve 9, there is no need to rotate the valve body 11 while it is in contact with the valve seat body 12, so when operating the valve body 11, a frictional force between the valve body 12 and the valve seat body 12 acts. This allows for smooth operation and delicate control.

〔effect〕

(1) The valve body is configured to be movable in the axial direction within the valve cylinder, and as the axis moves, the gap between the contact surfaces with the valve seat body is changed to adjust the opening degree of the passage and control the flow rate. Therefore, foreign matter such as abrasion powder caused by friction between the valve body and the valve seat body is not generated (it is possible to prevent foreign matter from entering the gas).

(2) As described above, even if the mass flow control valve is used to control the flow rate of processing gas for manufacturing semiconductor devices, a highly clean processing gas can be obtained, and the manufacturing yield of semiconductor devices can be improved.

(3) When adjusting the flow rate, there is no need to rotate the valve body while it is connected to the valve seat body, so there is no increase in operating force caused by friction between the two, and the operation is light and smooth. This enables delicate control of flow rate.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, the mechanism for operating the valve body can also utilize a link mechanism, a cylinder mechanism, etc. in addition to the above-mentioned configurations.

Furthermore, the minimum flow rate can be adjusted as appropriate by forming grooves or recesses on the joint surface of the valve body.

Further, each part can be made of a material such as quartz to withstand corrosive gas.

[Application field]

In the above explanation, the invention made by the present inventor was mainly applied to a control valve for controlling the flow rate of processing gas for manufacturing semiconductor devices, which is the field of application in which the invention was made, but the invention is not limited to this. It can be similarly applied to anything that controls the flow rate of liquid or other fluids.

[Brief explanation of drawings]

FIG. 1 is an overall sectional view of one embodiment of the present invention, and FIG.
FIG. 3 is a sectional view of a part of the conventional configuration, and FIG. 4 is a sectional view taken along line AA in FIG. 3. ■ Main channel, 2a, 2b, bulge, 3, detour, 4, flow rate limiting element, 5, mass flow meter, 6a. 6b... Self-heating resistor, 9... Control valve, 10... Valve cylinder, 11... Valve body, 12... Valve seat body, 15... First passage, 16... 2nd aisle, 17.
... Inlet boat, 18... Outlet boat, 19... Screw, 21... Pulse motor, 22... Rotating shaft, 23
...Fixed frame, 24.25...Seal ring, 30.
... Valve barrel, 31... Valve body, 32... Valve seat body, 35.
...First passage, 36... Second passage, 37... Inlet boat, 38... Outlet port, 39... Valve passage, 40
...Valve stick. Figure 2 Figure 3

Claims (1)

[Claims] 1. A valve cylinder disposed facing a fluid flow path, a valve body and a valve seat body housed within the valve cylinder, and relative movement between the valve body and the valve seat body. A mass flow control valve that controls the flow rate of fluid flowing through the flow path by varying and adjusting the opening degree of a passage opened in the valve seat body, the valve body being axially moved within the valve cylinder. configured so that it can be moved to
A mass flow control valve characterized in that the valve body is configured to move in the axial direction to change the distance between the contact surfaces with the valve seat body, thereby changing the substantial opening degree of the valve seat body passage. 2. The mass flow control valve according to claim 1, wherein the valve seat body has first and second passages communicating with the fluid passage, and both passages are opened at the joint surface with the valve body. . 3. The mass flow control valve according to claim 2, wherein the valve body has a flat joint surface, and when the valve body contacts the joint surface with the valve seat body, the first and second passages are closed.