JP7352947B2 - Valve devices and diversion systems - Google Patents

Description

The present invention relates to a valve device and a flow dividing system, and more particularly to a valve device and a flow dividing system that are suitably used in gas supply systems used in semiconductor manufacturing equipment, drug manufacturing equipment, chemical plants, and the like.

BACKGROUND ART In semiconductor manufacturing equipment, chemical plants, etc., it is required to supply gas to a process chamber or the like at an appropriate flow rate. Mass flow controllers (thermal mass flow controllers) and pressure flow controllers are known as devices for controlling flow rates.

Pressure flow control devices are widely used because they can control the mass flow rate of various fluids with high precision using a relatively simple mechanism that combines a control valve and a restrictor (for example, an orifice plate or critical nozzle). (For example, Patent Document 1). Further, the pressure-type flow rate control device has excellent flow rate control characteristics in that stable flow rate control can be performed even when the primary side supply pressure fluctuates greatly.

Gas may be supplied to the process chamber via a diversion system. In the split flow system, gas whose flow rate is controlled by the above-mentioned pressure type flow control device or the like is supplied to the process chamber from a plurality of split gas lines. The split gas lines are configured to supply gas to different regions of the process chamber. In this configuration, by controlling the on-off valve provided in each branch gas line, it is possible to selectively supply gas to a desired region in the process chamber or change the ratio of the amount of gas supplied to each region as appropriate. can. Such a flow dividing system is disclosed in Patent Document 2, for example.

Japanese Patent Application Publication No. 10-55218 Japanese Patent Application Publication No. 2015-49569

In particular, when using a diversion system, it is required that the characteristics of the on-off valves provided in each diversion gas line, and more specifically, the ease of gas flow (conductance) when the on-off valves are opened, are the same. There is. This is because if the opening/closing valves have different characteristics, it may become impossible to accurately control the ratio of the amount of gas flowing into each region of the process chamber. It goes without saying that even when the valve is incorporated into a system other than a diversion system, it is preferable that the characteristics of the valve remain constant.

The ease of gas flow in the on-off valve can be defined, for example, by a Cv value (Coefficient of flow). The Cv value is a general index indicating the ease of fluid flow in a valve, and the Cv value of gas is typically given by the following formula.
Cv=(Q/6900)×(Gg・T/(P1-P2)・P2) ^1/2

In the above formula, Q is the flow rate (sccm), Gg is the specific gravity of the gas, P1 is the valve primary pressure (kPa abs), P2 is the valve secondary pressure (kPa abs), and T is the temperature (K). . The Cv value corresponds to the flow rate of gas flowing through the valve when the primary and secondary pressures of the valve are constant.

The Cv value of the on-off valve provided in each branch gas line can be adjusted, for example, by mechanically adjusting the valve mechanism (valve body and drive device that drives the valve body). If the amount of movement of the valve body (valve lift) when the valves are opened can be adjusted to be the same for each on-off valve, the ease of flow in each branch gas line when the valves are open can be set to be the same.

However, it is often difficult to maintain a constant Cv value by adjusting the valve mechanism itself as described above. For example, if a piezo actuator is used as the drive mechanism, the stroke of the actuator will vary depending on the temperature, so the Cv value will vary depending on the usage conditions. Furthermore, when the valve seat is made of resin, the Cv value fluctuates as the valve element and the valve seat repeatedly come into contact and separate, which changes the gap when the valve is opened. Furthermore, the degree of adjustment required for the actually assembled valve mechanism varies due to processing errors in the valve body and valve seat, and it is not an easy task to finely adjust the Cv value of each valve.

The present invention has been made in order to solve the above problems, and provides a valve device and a valve device that can relatively easily adjust the ease of fluid flow when the valve is opened and reduce individual differences. Its main purpose is to provide a diversion system with

A valve device according to an embodiment of the present invention includes a main body provided with an inlet, an outlet, and a flow path between the inlet and the outlet, and a flow path between the inlet and the outlet. a valve mechanism intervening in the valve mechanism; a resistor body constituted by a plurality of resistance elements each having a flow passage portion and intervening in a flow path on the upstream side or downstream side of the valve mechanism; a fixture for fixing a resistor to the main body, and the plurality of resistance elements are removably held by the fixture.

In one embodiment, each of the plurality of resistance elements includes an annular plate on the surface of which a bottomed groove serving as the flow path is formed, and the resistor is configured by stacking the annular plates. .

In one embodiment, the fixture includes a shaft member into which the plurality of annular plates are commonly fitted, and the shaft member includes an axial member that is aligned with a bottomed groove formed in the annular plate. An extending notch is formed.

In one embodiment, the valve mechanism is provided on a first side of the main body, a housing space for accommodating the resistor is provided on the second side opposite to the first side, and the fixture is configured to The resistor is fixed to the main body from the second side.

In one embodiment, the accommodation space is a space whose diameter is larger than that of the flow path leading to the valve mechanism, and the resistor is arranged so as to be in contact with a bottom surface of the accommodation space.

In one embodiment, the device further includes an elastic member that urges the resistor toward the inner bottom surface.

In some embodiments, the Cv value passing through the valve mechanism is greater than the Cv value passing through the resistor.

A diversion system according to an embodiment of the present invention includes a gas supply source, a common line connected to the gas supply source, and a plurality of distribution gas lines commonly connected to the common line. Each of the plurality of branch gas lines is provided with one of the valve devices described above.

In some embodiments, the diversion system described above further includes a pressure sensor that measures fluid pressure upstream of the valve device.

According to the valve device and the flow dividing system according to the embodiments of the present invention, variations in the characteristics of the valve device can be improved relatively easily, and gas can be supplied at a desired flow rate.

FIG. 1 is a diagram showing a diversion system according to an embodiment of the present invention. FIG. 2 shows a process chamber to which gas is supplied. FIG. 1 is a sectional view showing a valve device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of a resistor and a fixture included in the valve device according to the embodiment of the present invention. FIG. 2 is a perspective view of a resistor and a fixture provided in the valve device according to the embodiment of the present invention after assembly. It is a perspective view showing an annular plate as a resistance element which constitutes a resistor with which a valve device of an embodiment of the present invention is provided.

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following embodiments.

FIG. 1 shows a flow diversion system 100 with a valve device 10 according to an embodiment of the invention. The diversion system 100 includes a gas supply source 2, a gas box 4 connected to the gas supply source 2, a common gas line L1 provided downstream of the gas box 4, and a common gas line L1 branched from the common gas line L1. A plurality of branch gas lines L2 are commonly connected to the line L1. Further, in this embodiment, a pressure sensor 8 is provided in the common gas line L1. The gas supplied from the gas supply source 2 may be various gases used in semiconductor manufacturing processes, such as source gas, etching gas, and carrier gas.

The gas box 4 includes, for example, a pressure-type flow rate controller interposed in the flow path from the gas supply source 2, and can control the flow rate of gas flowing through the common gas line L1 on the downstream side to a desired flow rate. . Although FIG. 1 shows one gas supply source 2 and one gas box 4, in other embodiments, a plurality of gas supply sources of different gas types are connected to the gas box 4, and the gas box There may be multiple flow controllers within 4 for each gas source. The downstream side of each flow rate controller may be connected to the common gas line L1 via a merging block (not shown).

In the diversion system 100, each of the diversion gas lines L2 is provided with the valve device 10 of this embodiment used as an on-off valve. Each valve device 10 includes a valve mechanism 30 and a resistor 20 provided upstream of the valve mechanism 30. The valve device 10 is typically adjusted so that gas flows through each branch gas line L2 with equal ease of flow. The detailed configuration of the valve device 10 will be described later.

The plurality of branch gas lines L2 are connected to the process chamber 6 to which gas is supplied. In the embodiment shown in FIG. 1, two branch gas lines L2 are commonly connected to line A on the downstream side of the valve device 10, and four branch gas lines L2 are commonly connected to line B on the downstream side of the valve device 10. , five branch gas lines L2 are connected to the line C downstream of the valve device 10. Lines A, B, and C each have supply ports at different locations in the process chamber 6.

FIG. 2 is a diagram showing an internal area of the process chamber 6. As shown in FIG. The process chamber 6 has, for example, a cylindrical processing space, and a region RA, a region RB, and a region RC are provided concentrically from the center of the chamber. In addition, the lines A, B, and C shown in FIG. 1 are connected to the areas RA, RB, and RC, and it is possible to flow gas from the gas supply source 2 to each of the areas RA, RB, and RC. It is. Note that, in order to simplify the drawing, only the right half of the process chamber 6 shown in FIG. 1 is shown, and the left end portion corresponds to the center of the process chamber 6.

Inside the chamber, a wafer is placed under a concentric room via a shower plate (not shown). In order to uniformly form a film on the wafer or to perform appropriate patterning, it is preferable to adjust the amount of gas blown from each region RA, RB, and RC. Further, it is preferable that the ratio of the amount of gas supplied from each region is appropriately selected depending on the pattern of the film formed on the wafer.

Referring again to FIG. 1, in the diverting system 100 having the above configuration, various flow ratio patterns (1:1:1, 1:2:1) can be created by controlling the opening and closing of the valve device 10 in each diverted gas line L2. , 1:3:1, etc.), the gas can be flowed into the regions RA, RB, and RC. The flow ratio pattern is determined by the number of branch gas lines L2 in which the valve device 10 is open.

The number of branch gas lines L2 to be opened in each line A, B, and C can be determined as appropriate based on line A in which one branch gas line is opened. In addition, when the output of the pressure sensor 8 exceeds the specified value, it is determined that the pressure on the downstream side of the gas box 4 is too high, and only in this case, multiple branch gas lines (here, two branch gas lines) are connected in line A. You may also open the line) to lower the pressure. Then, the number of opened branch gas lines in the other lines B and C may be determined based on the state in which the two branch gas lines in line A are opened, and with a lower pressure.

However, in order to supply gas to each region RA, RB, and RC in the process chamber with the desired various flow rate ratio patterns as described above, the gas flowability of each branch gas line L2 must be the same. It is preferable that If these flow easinesses are different, the gas will flow to each region at a flow rate ratio that is different from the ratio of the number of open branch gas lines.

On the other hand, the valve device 10 provided in each branch gas line L2 uses a resistor 20 provided on the upstream side of the valve mechanism 30 to facilitate gas flow when the valve is opened. It is configured to be adjustable. It is therefore possible to supply gas to each region of the process chamber at a desired flow rate ratio.

FIG. 3 shows the configuration of the valve device 10 of this embodiment. 4 is an exploded perspective view of the resistor 20 and fixture 24 included in the valve device 10, FIG. 5 is a perspective view of the resistor 20 and fixture 24 after assembly, and FIG. 2 is a perspective view showing an annular plate 22 as a resistance element constituting the body 20. FIG.

As shown in FIG. 3, the valve device 10 includes a main body 12 provided with an inlet 14, an outlet 16, and flow paths f1, f2, and f3 therebetween; ) 12U, and a resistor 20 provided in flow paths f1 and f3 between the inlet 14 and the valve mechanism 30.

The resistor 20 is housed in a housing space 12A that opens to the lower surface side (second side) 12D of the main body 12, and is fixed to the main body 12 using a fixture 24 that closes the housing space 12A. It is fixed to the main body 12 from the lower surface side of the main body 12. In the present embodiment, the fixture 24 is fixed to the main body 12 using a threaded portion 24b (see FIG. 4, etc.) formed around the fixture 24, but is not limited thereto. However, it is preferable that the fixture 24 is fixed to the main body 12 in a manner that it can be attached to and detached from the main body 12.

Further, an outer cover 18 is attached to the lower surface side of the main body 12 via a gasket ring 28 using screws or the like (not shown) so as to cover the fixture 24 attached to the main body 12. By attaching the outer lid 18 through the gasket ring 28 in this manner, the housing space 12A can be airtightly sealed from the outside.

Further, the accommodation space 12A is formed as a space whose diameter is larger than that of the flow path f3 leading to the valve mechanism 30, and the resistor 20 is arranged so as to come into contact with the inner bottom surface 12B of the accommodation space 12A. In this configuration, gas does not flow between the top surface of the resistor 20 and the bottom surface 12B of the housing space 12A. Furthermore, although not shown in the figure, by providing an elastic member that urges the resistor 20 toward the inner bottom surface, it is possible to press the resistor 20 against the inner bottom surface 12B and more effectively block the gas flow. can. As the elastic member, a disc spring or the like can be used.

The main body 12 is made of highly corrosion-resistant stainless steel such as SUS316L, and may include a joint portion having an inlet 14 and a joint portion having an outlet 16. A flow path f1 between the inflow port 14 and the accommodation space 12A, a flow path f2 between the storage space 12A and the mounting portion of the valve mechanism 30, and a flow path f3 between the mounting portion of the valve mechanism 30 and the outflow port 16. The accommodation space 12A can be formed inside the main body 12 by drilling with a drill or the like.

Further, in this embodiment, the valve mechanism 30 includes a diaphragm valve body 32, a valve seat 34 formed by an annular protrusion provided on the main body 12, and a drive mechanism 36 connected to the diaphragm valve body 32. We are prepared. As the drive mechanism 36, for example, a piezo actuator, an air-driven actuator, or the like can be used. Various drive mechanisms may be used as the drive mechanism 36 as long as they can press the diaphragm valve body 32 against the valve seat 34 or separate the diaphragm valve body 32 from the valve seat 34. The diaphragm valve body 32 is, for example, a circular thin plate (for example, 15 to 100 μm thick) made of stainless steel or cobalt-nickel alloy, and is formed into an inverted dish shape with a slightly bulged upward in the center. good. The diaphragm valve body 32 may be formed from a single diaphragm, or may be formed from a stack of 2 to 4 diaphragms.

The valve mechanism 30 is not limited to one using the diaphragm valve body 32 as described above, but may be of various other types such as a bellows valve or a needle valve as long as it can open and close the flow path. However, the valve mechanism 30 of the valve device 10 provided in each of the branch gas lines is designed to have the same predetermined Cv value when the valve body moves and becomes open (however, in reality Preferably, the Cv values of the two may be slightly different.

Next, details of the resistor 20 used in this embodiment will be explained with reference to FIGS. 4 to 6. The resistor 20 is configured using a plurality of resistance elements each having a flow path, and here is configured by stacking annular plates 22 as resistance elements. Further, the stacked annular plate 22 has its center opening 22b fitted into a shaft member 25 provided on the fixture 24, and is removably held by the fixture 24. The annular plate 22 and the fixture 24 are made of highly corrosion-resistant stainless steel such as SUS316L, for example.

Furthermore, a wide bottomed groove 22a is formed on the surface of the annular plate 22 as a flow path section. In the illustrated embodiment, four bottomed grooves 22a are arranged evenly in the circumferential direction, but the number and size of the grooves (groove width and groove depth) depend on the ease of flow required in the resistor 20. A plurality of patterns are prepared and may be selected as appropriate. Although the size of the annular plate 22 is not particularly limited, the outer diameter is, for example, 12 mm to 20 mm, the inner diameter is, for example, 6 mm to 10 mm, and the thickness is, for example, 0.1 mm to 0.3 mm. . The annular plate 22 may have a similar configuration to a bypass plate included in a known thermal flowmeter.

However, the annular plate 26 disposed at the top of the annular plates 22 does not need to be provided with a groove, and this annular plate 26 is provided to close the bottomed groove 22a of the annular plate 22 below. ing. In addition, an elastic member (such as an annular disc spring or a coil spring) for biasing the uppermost annular plate 26 toward the inner bottom surface 12B of the accommodation space 12A of the main body 12 may be incorporated in the middle of the stacked annular plates 22, It may be provided below the annular plate 22 at the lowest stage, that is, on the stepped surface of the fixture 24. However, generally, it is sufficient to press the annular plate 26 against the inner bottom surface 12B with an appropriate pressing force by adjusting the screws of the fixture 24.

The plurality of annular plates 22 having the above configuration are stacked with their respective bottomed grooves 22a aligned. A notch 25a extending in the axial direction and aligned with the bottomed groove 22a formed in the annular plate 22 is formed in the shaft member 25 of the fixture 24 into which the plurality of annular plates 22 are commonly fitted. There is. Similarly to the bottomed groove 22a, four notches 25a are provided evenly in the circumferential direction.

The gas that has passed through the bottomed groove 22a flows through the notch 25a to the flow path f3 that communicates with the valve mechanism 30. On the other hand, gas cannot flow through a portion where the bottomed groove 22a is not provided. Therefore, the resistor 20 can be used as a flow restrictor whose ease of flow depends on the number and size of the bottomed grooves 22a.

Furthermore, in this embodiment, by increasing the number of annular plates 22, a resistor 20 through which gas flows more easily can be obtained, and by decreasing the number of annular plates 22, a resistor 20 through which gas is more difficult to flow can be obtained. Therefore, by using the resistor 20, the ease of gas flow on the upstream side of the valve mechanism 30 or the pressure of the gas immediately before the valve mechanism 30 can be adjusted. This makes it possible to adjust the ease with which gas flows through the resistor 20 and the valve mechanism 30, that is, the overall Cv value of the valve device 10.

Here, in order to adjust the overall Cv value of the valve device 10 (Cv value based on the primary side pressure and secondary side pressure of the valve device 10 and the flow rate of gas flowing at that time) using the resistor 20, The Cv value of the valve mechanism 30 (Cv value when passing through the valve mechanism 30 in a fully open state) is required to be larger than the Cv value of the resistor 20 (Cv value when passing through the resistor 20). This means that when the Cv value of the resistor 20 is larger than the Cv value of the valve mechanism 30, the ease of gas flow in the valve device 10 is determined by the Cv value of the valve mechanism 30, regardless of the adjustment of the Cv value of the resistor 20. This is because it is decided. Therefore, it is preferable that the Cv value of the resistor 20 is adjusted, for example, the number of annular plates is adjusted within a range where the Cv value of the resistor 20 does not exceed the Cv value of the valve mechanism 30.

Note that the number of annular plates may be selected as appropriate in consideration of the required flowability and the Cv value of the valve mechanism 30, but it is preferably 5 or more, and 10 or more. More preferred. When the number of sheets is large, the Cv value, which can be adjusted by increasing or decreasing one sheet, can be set to a small value, so the ease of flow can be adjusted more precisely.

In this way, in this embodiment, a stack of a plurality of annular plates is used as the restrictor, and the grooves provided in the annular plates can be formed with relatively high precision in shape. On the other hand, it is conceivable to use orifice plates of different sizes as restrictors, but it is often difficult to increase the processing accuracy of orifice formation. Therefore, by using a stack of a plurality of annular plates instead of an orifice plate, it becomes possible to adjust the Cv value with higher accuracy.

Although the embodiments of the present invention have been described above, various modifications are possible. For example, the fixture may not have the shaft member as described above, but may have a plurality of wall-like members configured to support the outer peripheral side of the stacked annular plates 22. Moreover, the annular plates 22 to be stacked do not necessarily need to be composed only of plates having similar flow path portions (grooves). For example, if the number of grooves provided in the annular plate is two, it will be more difficult for gas to flow than in a plate with four grooves. Therefore, by combining these multiple types of plates, it becomes possible to adjust the Cv value with greater flexibility.

Further, the resistor 20 may be configured to include a plate without a flow path in addition to a plate provided with a flow path. As long as the resistor 20 includes a plurality of resistance elements having flow path portions, it will be referred to herein as a resistor constituted by a plurality of resistance elements, regardless of the presence or absence of other components.

Further, the valve device may be of a normally closed type or a normally open type. Further, the valve device can be applied not only to an on-off valve but also to a valve whose opening degree can be adjusted arbitrarily.

Furthermore, although the embodiment in which the resistor is provided on the upstream side of the valve mechanism has been described above, the resistor may be provided on the downstream side of the valve mechanism. In the embodiment shown in FIG. 3, such an embodiment can be realized by connecting the outflow port 16 to the gas inflow side and connecting the inflow port 14 to the gas discharge side. Further, in the embodiment shown in FIG. 3, the resistor 20 is provided in the vertical flow path f3 arranged inside the valve seat 34, but in the middle of the flow path connected to the valve chamber outside the valve seat 34. A housing space and a resistor may be provided in the housing.

The valve device and the flow dividing system according to the embodiments of the present invention are suitably used, for example, in a gas supply line in semiconductor manufacturing equipment.

2 Gas supply source 4 Gas box 6 Process chamber 8 Pressure sensor 10 Valve device 12 Main body 12A Housing space 12B Bottom surface 14 Inlet 16 Outlet 18 Outer cover 20 Resistor 22 Annular plate 22a Bottomed groove (flow path)
22b Central opening 24 Fixture 28 Gasket ring 30 Valve mechanism 32 Diaphragm valve body 34 Valve seat 36 Drive mechanism 100 Diversion system

Claims (8)

a main body provided with an inlet, an outlet, and a flow path between the inlet and the outlet;
a valve mechanism interposed in the flow path between the inlet and the outlet;
a resistor that is interposed in a flow path on the upstream side or downstream side of the valve mechanism and is constituted by a plurality of resistance elements each having a flow path portion;
a fixture for holding the resistor and fixing the resistor to the main body,
the plurality of resistance elements are removably held with respect to the fixture ;
Each of the plurality of resistance elements includes an annular plate on the surface of which a bottomed groove serving as the flow path portion is formed, and the resistor is configured by stacking the annular plates. The fixture has a shaft member into which the plurality of annular plates are commonly fitted, and the shaft member has an axially extending notch that is aligned with a bottomed groove formed in the annular plate. A valve device according to claim 1 , wherein the valve device is formed. The valve mechanism is provided on a first side of the main body, an accommodation space for accommodating the resistor is provided on a second side opposite to the first side, and the fixture is provided on the second side. 3. The valve device according to claim 1 , wherein the resistor is fixed to the main body. 4. The valve device according to claim 3 , wherein the housing space is a space whose diameter is larger than that of a flow path leading to the valve mechanism, and the resistor is arranged so as to come into contact with a bottom surface of the housing space. . The valve device according to claim 4 , further comprising an elastic member that urges the resistor toward the inner bottom surface. 6. The valve device according to claim 1 , wherein a Cv value passing through the valve mechanism is larger than a Cv value passing through the resistor. A distribution system comprising a gas supply source, a common gas line connected to the gas supply source, and a plurality of distribution gas lines commonly connected to the common gas line, the system comprising:
A diversion system, wherein each of the plurality of diversion gas lines is provided with the valve device according to any one of claims 1 to 6 . 8. The flow diversion system of claim 7 , further comprising a pressure sensor that measures fluid pressure upstream of the valve device.