JP2003323218A - Apparatus for controlling flow rate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for controlling a flow rate, which minimizes pressure losses. <P>SOLUTION: The apparatus 1 for controlling the flow rate comprises a main flow channel and a flow route with fluctuation of one conductance or more and also uses a differential control valve with a pair of orifices, the conductance of the flow rate of which freely and differentially varies. A part of the differential control valve consists of a cylinder that includes a valve head 3, which has a first valve head unit located at one side of an axis direction of the cylinder and a second valve head unit located at the other side of the cylinder axis direction. Each of first orifice and second orifice is configured with the first and the second valve head units within a orifice body 2. The valve head 3 controls the flow rate by dividing the flow from the main flow channel, which is connected to a center unit of the valve head of the orifice body, into two flow routes by keeping a free position of the valve head to the direction of the axis. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid control technique for stably supplying a gas or liquid source material to a process chamber in a semiconductor manufacturing process.

[0002]

2. Description of the Related Art In order to improve the throughput of a process, the same flow rate of source material is supplied to a plurality of chambers and the processes are simultaneously performed under the same conditions to increase the number of wafers processed per unit time. And there are needs. When the source material is a single gas, a plurality of mass flow controllers can be used to supply the source material at the same flow rate to a plurality of chambers relatively easily.

However, when the source material is a liquid and the liquid must be bubbled with an inert gas such as nitrogen gas and supplied together with the inert gas, it cannot be easily performed. . Because, when the bubbling method is used, the vapor pressure of the source material is low, it is necessary to control the flow rate of the inert gas flowing into the source tank by using the mass flow controller as the decompression of the source tank. As a result, it is necessary to guide the source material mixed in the inert gas and flowing out from the source tank together with the inert gas to the process chamber without giving a pressure loss, and when some pressure loss occurs, the source material is liquefied there. This is because it can happen.

Therefore, since a general mechanical flow rate dividing device requires an operating differential pressure of about 10 PSIG (about 69 kPa), it cannot be installed after the source tank to divide the flow rate.

On the other hand, providing a plurality of supply sides including the source tank increases the cost, and since the source material having the same concentration is supplied, it is not easy to manage the temperature of the source tank and the like at exactly the same level. .

[0006]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention provides a flow rate ratio control device capable of diverting a fluid with a small pressure loss and controlling the flow rate ratio thereof. The purpose is to

[0007]

In order to achieve the above-mentioned object, a flow rate control device of the present invention comprises one main flow channel and one or more flow passages in which the conductance fluctuates. The differential control valve is provided with a pair of orifices in which the ratio of the conductance of (1) is changed arbitrarily and differentially.

More specifically, in the flow rate controller of the present invention, the differential control valve has a part having a cylindrical shape, and one of the cylindrical parts sandwiches the cylindrical shape in the axial direction. A generally columnar axially movable valve head having a first valve head on one side and a second valve head on the other side, and an orifice movably accommodating said valve head in the axial direction. A main body, a first valve seat is provided adjacent to the first valve head to form a first orifice, and a second valve seat is adjacent to the second valve head. An orifice body having a second orifice formed therein, and an actuator for moving and holding the axially movable valve head at an arbitrary axial position. Provided in a first flow path connected to the first orifice A flow rate detecting device including a first flow rate detecting device and a second flow rate detecting device provided in a second flow path connected to the second orifice; Depending on the output, the actuator holds the movable valve head in place in the axial direction to allow flow from the orifice body to the main flow channel leading to the central portion of the valve head. Is divided into a flow passing through the first orifice and a flow passing through the second orifice, and the flow rate ratio between the flow rate flowing through the first flow path and the flow rate flowing through the second flow path is controlled. ing.

Further, as another mode, the flow rate control device of the present invention includes an orifice body having a donut-shaped disc portion as a part thereof, and the valve head is housed in the center hole of the donut-shaped disc portion. The donut-shaped disc portion has a first valve seat formed at one end portion in the axial direction of the central hole of the donut-shaped disc portion, and a first orifice formed between the first valve seat and the first valve head. The second valve seat may be formed at the other end of the center hole of the disc portion in the axial direction so that a second orifice is formed between the second valve seat and the second valve head. In this case, in the orifice body,
A first flow path to the first orifice and a second flow path to the second orifice are provided, and the first flow path has a first flow rate sensor for detecting a flow rate. A second flow rate sensor for detecting the flow rate is provided in the second flow path.

The flow rate control in the flow rate control device of the present invention is performed by, for example, calculating the output of the first or second flow rate sensor by the sum of the output of the first flow rate sensor and the output of the second flow rate sensor. This can be done by controlling the position of the movable valve head so that the divided value becomes a predetermined value.

[0011]

1 is a sectional view of a main portion of a first embodiment of a flow rate control system according to the present invention as seen from the front. This flow rate ratio control device is a fluid control device for stably supplying a process gas to each process chamber in a semiconductor manufacturing process. FIG. 2 is a top view of this device, and FIG. 3 is a side sectional view. Figure 8
2 is an external view of the flow rate control device shown in FIG. 1.

The process gas to be controlled is introduced from the main flow channel from the right side of the valve body 1, as indicated by the arrow in FIGS. The orifice body 2 is tightly fitted and fixed to the valve body 1. In the center of the orifice body 2, a hole is provided so that the valve head 3 can move therein, and further, a hole for communicating the main flow channel of the valve body 1 with the hole in the center is provided. . FIG. 6 is a diagram showing details of the orifice body 2.

Details of the valve head 3 are shown in FIG. As can be seen from FIG. 5, the valve head 3 has a cylindrical portion 4 partially.
Has a first valve head 5 which is a slope on one side sandwiching the cylindrical shape in the axial direction of the cylindrical shape part 4, and a second valve head 6 on the other side. is doing. On the other hand, as can be seen from FIG. 6, in the central hole of the orifice body 2,
The first valve seat portion 7 is provided at a position corresponding to the first valve head 5 of the valve head 3.
And a second valve seat portion 8 is provided at a position corresponding to the second valve head 6. A first orifice is formed between the first valve head 5 and the first valve seat portion 7, and a second orifice is formed between the second valve head 6 and the second valve seat portion 8. An orifice is formed. Therefore, the fluid flow from the main flow channel is split into two streams by the first orifice and the second orifice around the circumference of the central cylindrical portion of the valve head 3. The valve head is connected to a plunger 10 via a disc spring 9, and the plunger 10 is
The electromagnet assembly 11 allows the plunger 10 and the valve head 3 to be controllably moved in the axial direction against the biasing force of the disc spring 9 to adjust the axial position of the valve head 3. The electromagnet assembly 11 includes the plunger 10
It is composed of a yoke 12, a solenoid coil 13, a solenoid case 14 and the like which are connected to each other. The electromagnet assembly 11 is coupled to the valve body 1 via the gasket 15. In this embodiment, the disc spring 9
Is shaped so as to bias the valve head 3 and the plunger 10 downward in the axial direction, and the valve head 3 and the plunger 10 are pulled upward by the electromagnetic force of the electromagnet assembly 11 against this biasing force. It is done like this. Therefore, in the normal state described below, the electromagnet assembly is in an electrically biased state.

FIG. 7 shows three states of movement of the valve head 3 with respect to the orifice body 2. In the state of (a), the valve head 3 is urged upward in the axial direction, the first orifice is larger than the second orifice, and the flow rate through the first orifice causes the second orifice to open. More than the flow rate through. In the state of (b), the valve head 3 is located at a substantially central position in the axial direction with respect to the orifice body 2. In this state, the first orifice and the second orifice are closed to the same degree, and the space between the periphery of the valve head 3 and the orifice body 2 is passed through the first orifice and the second orifice. The flow is divided evenly.
In the case of the present embodiment, a slight gap is provided between the outer circumference of the valve head and the hole of the orifice body in order to allow the gas to flow in both flow paths even in the state of (b). ,
As a more tight fit, the flow rate may be almost eliminated in the state of (b). The state of (c) is (a)
Conversely, the second orifice is wider than the first orifice, and the flow rate through the second orifice is higher than the flow rate through the first orifice.

Therefore, for example, a flow rate detecting device including a flow rate sensor and a laminar flow element such as a combination of the thermal flow sensor 16 and the laminar flow element 17 shown in FIG. It is provided in each of the passages, the flow rate of each passage is detected, and the electromagnet assembly 11
By moving and holding the valve head 3 in the axial direction and adjusting the balance of the openings of the first and second orifices, the flow rate ratio of the two flow paths can be controlled. For example, in the control of the flow rate of the flow rate control device of the present embodiment, the output of the first or second flow sensor is divided by the sum of the output of the first flow sensor and the output of the second flow sensor. This can be done by controlling the position of the valve head 3 so that the value becomes a predetermined value.

10 and 11 are a top view, a front cross section and a side cross section of a second embodiment of the present invention. This embodiment differs from the first embodiment in that the means for driving the valve head 23 uses a piezo actuator 24 instead of an electromagnet. In FIG. 11, the orifice body 22 is fitted and fixed inside the valve body 21. A stepped hole is provided at the center of the orifice body 22, and a valve head 23 is inserted into this hole so that a predetermined gap is formed between the hole and the orifice body. 23 is movable in the axial direction in the center hole of the orifice body. A piezo actuator 24 is fixed to one end of the valve head 23, and the valve head 23 is axially moved and held by the operation of the piezo actuator 24. The valve head 23 has a cylindrical portion 25 in a part thereof, and a first valve head 26 is provided at one end of the cylindrical portion on one side in the axial direction, and an end on the other side is provided. A second valve head 27 is provided on the. Both valve heads are in the form of an annular ridge, as can be seen from the drawing. The first and second valve heads 26, 27 of the valve head 23 are adapted to form first and second orifices with opposing surfaces of the orifice body, as shown.

As shown by the arrows in FIGS. 10 and 11, the fluid is introduced from the lower right side in FIG. 11 through the main flow channel, and through the hole provided in the orifice body 22, the valve head 23. Into the chamber on the outer periphery of the center of the columnar part, and through the chamber, the flow is split into the first orifice and the second orifice.

The flow rate ratio control in this embodiment is controlled in substantially the same manner as in the first embodiment. That is, for example, a flow rate detecting device including a flow rate sensor and a laminar flow element such as a combination of the thermal flow sensor 16 and the laminar flow element 17 shown in FIG. 9 is provided in each of the first flow path and the second flow path. By detecting the flow rate of each flow path,
According to this detection result, the piezo actuator 24 moves and holds the valve head 23 in the axial direction to adjust the balance between the openings of the first and second orifices, thereby controlling the flow rate ratio of the two flow paths. You can

[0019]

As described above, the flow rate control device of the present invention uses the differential control valve having the pair of orifices in which the ratio of the conductance is changed arbitrarily and differentially. The pressure loss can be reduced. Further, since it is a differential control valve, it is not affected by the dynamic pressure of the fluid, the size of the valve is not limited, and it is possible to favorably control a valve having a considerably large diameter. Therefore,
A large flow rate can be controlled, and extremely reliable flow rate ratio control is possible.

FIG. 12 is a graph comparing the pressure loss between the conventional mechanical flow splitter and the flow rate controller according to the present invention. As is clear from the graph, the flow rate control device of the present invention has extremely less pressure loss than the conventional device.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a first embodiment of a flow rate control device of the present invention as seen from the front.

FIG. 2 is a top view of the device of FIG.

FIG. 3 is a side sectional view.

FIG. 4 is an external view of an electromagnet assembly.

5 is an enlarged detailed view of the valve head 3. FIG.

FIG. 6 is a diagram showing details of an orifice body.

FIG. 7 shows three states of movement of the valve head 3 with respect to the orifice body 2.

FIG. 8 shows an appearance of the flow rate control device shown in FIG.

FIG. 9 is a schematic diagram of a flow rate detection device in which a thermal flow sensor and a laminar flow element are combined.

FIG. 10 is a view showing a front surface and a cross section of a second embodiment of the present invention.

11 is a side cross-sectional view of the device shown in FIG.

FIG. 12 is a graph comparing pressure loss between a conventional mechanical flow splitter and a flow rate control device according to the present invention.

[Explanation of symbols]

1 valve body, 2 orifice body, 3 valve head,
4 Cylindrical-shaped part, 5 1st valve head, 6 2nd valve head, 7 1st valve-seat part, 8 2nd valve-seat part,
9 disc spring, 10 plunger, 11 electromagnet assembly, 12 yoke, 13 solenoid coil, 14 solenoid case, 15 gasket, 16 thermal flow sensor, 17 laminar flow element, 21 valve body, 22 orifice body, 23
Valve head, 24 piezo actuator, 25 cylindrical portion, 26 first valve head, 27 second valve head

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5F045 AA04 EE03 EE04 EE17                 5H307 AA20 BB01 CC03 DD07 EE02                       EE07 EE12 ES02 FF06 FF08                       GG05 GG09 HH04                 5H309 AA20 BB20 CC20 DD10 EE04                       FF03 FF06 FF20

Claims (5)

[Claims] 1. A flow rate ratio control device comprising one main flow channel and one or more flow passages with varying conductance, wherein the conductance ratio is changed arbitrarily and differentially. A flow rate ratio control device comprising a differential control valve having a pair of orifices. 2. The flow rate control device according to claim 1, wherein the differential control valve has a part having a cylindrical shape, and one of which sandwiches the cylindrical shape in the axial direction of the cylindrical part. A generally valve-shaped axially movable valve head having a first valve head on its side and a second valve head on the other side, and said valve head is housed movably in the axial direction. An orifice body, a first valve seat is provided in the vicinity of the first valve head to form a first orifice, and a second valve is formed in the vicinity of the second valve head. An orifice body provided with a seat so as to form a second orifice, and an actuator for moving the axially movable valve head to an arbitrary position in the axial direction and holding the position. And provided in a first flow path connected to the first orifice A flow rate detection device including one flow rate detection device and a second flow rate detection device provided in a second flow path connected to the second orifice, and an output of the flow rate detection device. According to, the movable valve head is held in position in the axial direction by the actuator, so that the flow from the main flow channel leading from the orifice body to the central portion of the valve head, The flow rate is divided into a flow passing through the first orifice and a flow passing through the second orifice, and the flow rate ratio between the flow rate flowing through the first flow path and the flow rate flowing through the second flow path is controlled. , Flow rate control device. 3. The flow rate control device according to claim 2, further comprising an orifice body having a donut-shaped disc part, wherein the valve head is housed in a central hole of the donut-shaped disc part. The donut-shaped disc portion is formed with the first valve seat at one end portion in the axial direction of the center hole of the donut-shaped disc portion, and the first orifice is formed between the first valve seat and the first valve head. The flow rate ratio is such that the second valve seat is formed at the other end in the axial direction of the central hole of the disk portion, and the second orifice is formed between the second valve seat and the second valve head. Control device. 4. The flow rate control device according to claim 3, wherein the orifice body has a first flow path leading to the first orifice and a second flow path leading to the second orifice. Is provided, the first flow path is provided with a first flow rate sensor for detecting a flow rate, and the second flow path is provided with a second flow rate sensor for detecting a flow rate. A flow rate ratio control device, which is provided. 5. The flow rate control device according to claim 4, wherein the output of the first or second flow sensor is the sum of the output of the first flow sensor and the output of the second flow sensor. A flow rate control device in which the flow rate is controlled by controlling the position of the movable valve head so that the value divided by is a predetermined value.