Gas inlet valve with improved flow geometry

Abstract

This invention relates to an inlet valve (1) for controlling fluid entry into a vacuum process chamber, wherein the inlet valve (1) comprises: a gas application unit (2) having a gas inlet (21), a gas outlet (22), and an internal volume (23) connecting the gas inlet (21) and the gas outlet (22), wherein the gas application unit has a valve seat body (24) with a sealing surface (24a) in the internal volume (23); an adjustment unit (4) having a valve plate (45) extending into and disposed within the internal volume (23) and having a seal (46), wherein the adjustment unit (4) is movably mounted along an adjustment shaft (V) in a closing direction (S) and an opening direction (O), and the valve plate ( The valve plate (45) and valve seat body (24) are configured to correspond to each other such that the seal (46) contacts the sealing surface (24a) in the closed position; a drive unit (3) coupled to an adjustment unit (4) outside the gas application unit (2) and providing adjustment of the adjustment unit (4) along the adjustment axis (V), wherein the valve plate (45) can be brought into the open position in the opening direction (O) by the drive unit (3), in which the seal (46) is spaced apart from the sealing surface (24a) and provides a fluid passage; and a flexible sealing element (25) configured as a diaphragm connected to the gas application unit (2) and the adjustment unit and atmospherically isolating the drive unit (3) from the internal volume (23). The valve seat body (24) is formed annularly around the adjustment axis (V) and has an annular end face (26) facing the valve plate (45). The annular end face (26) includes an inner partial surface (27) and an outer partial surface (28), wherein the distance between the inner partial surface (27) and the adjusting shaft (V) is less than the distance between the outer partial surface (28) and the adjusting shaft (V). The outer partial surface (28) has a sealing surface (24a).

Description

[Technical Field]

[0001] This disclosure relates to an intake valve for introducing fluid into a vacuum processing chamber, which has an improved flow channel structure. [Previous Technology]

[0002] Vacuum process chambers are used in the production of integrated circuits (ICs), semiconductors, flat panel displays, or substrates, where the chamber is filled with process gases for at least some of the process steps after being evacuated. Production must be carried out in a protective atmosphere, as free of contaminating particles as possible. Evacuation is performed using a vacuum valve that connects the vacuum process chamber to a vacuum pump. Vacuum valves differ fundamentally from inlet valves in configuration, technical requirements, and application. General-purpose inlet valves are configured to explicitly apply fluid to the vacuum process chamber (upstream), while classic vacuum valves are used to regulate pressure conditions within the chamber (downstream) or for loading and unloading the chamber. The opening cross-section, closing and opening times, and sealing requirements therefore differ.

[0003] In addition, the vacuum chamber has at least one or two vacuum chamber openings through which the device to be processed can be introduced into and / or exported from the vacuum chamber. For example, in semiconductor wafer or liquid crystal substrate manufacturing equipment, highly sensitive semiconductor or liquid crystal devices are sequentially passed through multiple vacuum process chambers, where each device is processed using a separate processing device.

[0004] Components can be placed, for example, using a robot on an extended support pin of a lifting system, and then placed on a carrier, such as a chuck, by lowering the support pin. Typically, the robotic arm carrying the component then removes it from the chamber. The pin can be lowered after component placement and then separated from the component, meaning there is no contact between the pin and the component. After the robotic arm is removed and the chamber is closed, the chamber is typically evacuated and then filled with process gas before component processing can begin.

[0005] The intake valve is used to fill one or more specific process gases or precursors into the process chamber. Therefore, different substrate treatments can be provided, such as precise deposition of material layers on the wafer or etching of the wafer surface. In particular, a specific amount of process fluid is released into the process chamber, and the reaction between the process fluid and the wafer is initiated or accelerated, for example, through plasma.

[0006] Inlet valves are specifically designed for precise control or regulation of gas flow and are located, for example, within a piping system between a vacuum process chamber (or transfer chamber) and a gas source, atmosphere, or other vacuum process chamber. The opening cross-section of such inlet valves is typically significantly smaller than that of vacuum valves.

[0007] Depending on the application, the intake valve can not only fully open and close the opening, but also control or regulate the flow rate by continuously adjusting the opening cross-section between the open position and the airtight closed position.

[0008] When introducing process gas into a vacuum chamber, minimal flow effects within the chamber and rapid, precise filling are crucial. For example, a precisely defined amount of process gas should be introduced into the chamber during one opening cycle of the inlet valve. Therefore, rapid valve start-up and precise adjustment of the valve opening cross-section are desirable.

[0009] Furthermore, the flow characteristics through the intake valve are also crucial here. The flow through the valve should be as uniform as possible so that there is as little or no turbulence or eddies as possible in the process chamber. Turbulence and eddies in the chamber can cause deposited particles to be agitated, leading to process contamination. Classic intake valves according to the prior art already have sufficient flow constancy, but the corresponding requirements are constantly increasing. Flow constancy is generally still acceptable today, but should continue to be improved for further refinement and reliable processes.

[0010] According to existing technology, classic intake valves already have sufficient flow constancy, but the corresponding requirements are constantly increasing. Flow constancy is generally still acceptable today, but should continue to be improved for further refinement and reliable processes. [Summary of the Invention]

[0011] Therefore, the object of the present invention is to provide an improved intake valve for vacuum processes to avoid the above-mentioned disadvantages.

[0012] In particular, the objective is to provide an intake valve for a processing system, thereby enabling rapid and continuous flooding of a vacuum process chamber with process gas.

[0013] This invention relates to an intake valve, wherein the seal is disposed rearward from the gas connection, particularly the gas inlet. The seal is configured such that it is not located within the flow-limiting area of ​​the connection, but rather at a certain distance from the flow-limiting area. This prevents the seal from adversely affecting the flow limitation. The seal is typically made of an elastic material. This elasticity and flexibility of the seal may have a corresponding negative impact on the constancy of the flow rate. In particular, changes in flow characteristics may occur due to thermal expansion or dimensional reduction of the seal.

[0014] Therefore, the sealing line, that is, the line on which the seal engages with or adheres to the valve seat or the sealing surface provided by the valve seat when the valve is closed, can be set at a position that is at a distance from the flow-related area.

[0015] Due to this configuration of the sealing line, improved flow or flow rate constantness is provided through the gas application unit.

[0016] Therefore, the present invention relates to an inlet valve for controlling the entry of fluid into a vacuum process chamber, wherein the inlet valve includes a gas application unit having a gas inlet, a gas outlet, and an internal volume connecting the gas inlet and the gas outlet. The gas application unit has a valve seat body with a sealing surface in the internal volume.

[0017] In the context of this invention, fluid is understood to be at least one gas, a gas mixture, or a gas containing a precursor. Fluid may in particular be a process gas or a precursor gas.

[0018] In addition, an adjustment unit with a valve plate extending into the internal volume is provided. The valve plate is disposed within the internal volume and has a seal, namely a sealing material provided to form an airtight seal. The adjustment unit is movably mounted along the adjustment shaft in the closing and opening directions. The valve plate and valve seat body are configured to correspond to each other such that the seal contacts the sealing surface when in the closed position. As a result, the flow of fluid through the gas application unit can be interrupted.

[0019] The intake valve further includes a drive unit coupled to an adjustment unit external to the gas application unit, and provides adjustment or movement of the adjustment unit along an adjustment axis. The valve plate can be brought into an open position in the opening direction by the drive unit, in which the seal is spaced apart from the sealing surface and provides a fluid passage.

[0020] The drive unit may include a motor or pneumatic system for adjusting the adjustment element.

[0021] In addition, the flexible sealing element is configured as a diaphragm that is connected to the gas application unit and the adjustment unit and isolates the drive unit from the internal volume atmosphere.

[0022] The valve seat body is formed in an annular shape around the adjusting shaft and has an annular end face facing the valve plate. The annular end face includes an inner partial surface and an outer partial surface, wherein the distance of the inner partial surface from the adjusting shaft is less than the distance of the outer partial surface from the adjusting shaft. The outer partial surface includes a sealing surface.

[0023] In one embodiment, the inner portion surface may be larger than the outer portion surface. This results in a correspondingly larger distance between the sealing surface that mates with the seal and the adjusting shaft, and therefore between the sealing surface and the gas inlet. This can thus provide further improved flow rate constancy.

[0024] According to one embodiment, the inner part surface and the outer part surface may be formed in an annular shape, particularly around the adjustment axis.

[0025] In one embodiment, the valve seat body may include or extend around a cylindrical recess forming a gas inlet or gas outlet, wherein the recess has a cross-sectional area orthogonal to the adjustment axis orientation.

[0026] In particular, the radius of the cross-sectional area may include the corner radius, wherein the corner radius is defined by the curvature path of the surface between the lateral surface and the end face of the recess.

[0027] In particular, the end face can be located on the valve seat plane, and the projection of the cross-sectional area onto the valve seat plane can define the inner boundary of the end face, and the projection of the path of the seal onto the valve seat plane, especially the projection of the sealing line, can define the outer boundary of the end face.

[0028] In particular, the end face is orthogonally aligned with the adjustment shaft.

[0029] In one embodiment, the inner side surface may be defined by the perimeter of the inner boundary of the end face and the distance between the end face and the valve plate surface of the valve plate.

[0030] The seal extends particularly around the surface of the valve plate.

[0031] The outer side surface can be defined accordingly by the perimeter of the outer boundary of the end face and the distance between the end face and the seal, especially the distance between the end face and the bottom surface of the seal.

[0032] In one embodiment, the valve seat body and the valve plate may be configured such that the outer side surface is larger than the inner side surface. In particular, in the open position of the valve, i.e., when there is no contact between the sealing surface and the seal, the outer side surface may be larger than the inner side surface.

[0033] In the open position, there is a distance between the end face and the seal. This distance can be greater than 0.05 mm and less than 1.0 mm, especially less than 0.75 mm or 0.55 mm.

[0034] In one embodiment, the valve seat body and the valve disc may be formed such that the area ratio of the outer side surface to the inner side surface is greater than 1:1 and less than 5:1.

[0035] In one embodiment, the seal may be attached to the valve plate and protrude from the valve plate at a sealing height h, especially in the closing direction.

[0036] In particular, the sealing height h can satisfy: 0.1mm < h < 0.5mm.

[0037] According to one embodiment, when the valve plate, particularly the valve plate surface, is in the open position, the distance d between it and the sealing surface of the valve seat body can satisfy: 0.2mm < d < 1.2mm. In particular, the distance d can be greater than 0.25mm and less than 1.0mm.

[0038] Specifically, in the closed position, the valve plate divides the internal volume into a first internal volume and a second internal volume, wherein the gas inlet can freely enter the first internal volume and the gas outlet can freely enter the second internal volume. In this configuration, the gas outlet can be connected to the vacuum chamber, and in particular, can freely enter the vacuum process chamber, while the gas inlet can in particular freely enter the process gas source.

[0039] The intake valve of the present invention will be described in more detail below with reference to exemplary embodiments schematically shown in the drawings, purely by way of example. The same elements in the drawings are labeled with the same reference numerals. The described embodiments are generally not shown to scale and should not be construed as limiting.

Implementation Method

[0043] FIG1 shows a cross-sectional view of an embodiment of the intake valve 1 according to the present invention.

[0044] The intake valve 1 includes a gas application unit 2, which in turn includes a gas inlet 21, two gas outlets 22, and an internal volume 23, wherein the internal volume 23 is freely accessible to or connected to the gas inlet 21 and the gas outlets 22. The gas application unit 2 has a sealing surface 24a in the internal volume 23. The sealing surface 24a forms, in particular, the valve seat of the intake valve 1 and is part of the valve seat body 24.

[0045] In an alternative embodiment not shown, the intake valve 1 may have a single or multiple gas outlets.

[0046] The intake valve 1 also has a drive unit 3. In the illustrated embodiment, the drive unit 3 is configured to be pneumatically driven. However, it is understood that, according to alternative embodiments of the invention, an electromechanical drive unit with an electric motor can be provided.

[0047] The intake valve 1 is shown in the open position, meaning that fluid can flow through the internal volume 23, particularly from the gas inlet 21 to the gas outlet 22. The pneumatic drive unit 3 includes a first lifting piston 31 and a second lifting piston 32, which can be moved in the opening direction O by pressurization within their respective lifting cylinders, thus moving the valve 1 to the open position. Pressurization can be provided via respective compressed air passages or compressed air inlets 31a and 32a, here provided by hollow screws with outlet holes.

[0048] Furthermore, the return element 33, such as a spring, is configured to generate a restoring force in the closing direction S. This restoring force is applied directly to the first lifting piston 31, and also acts on the second lifting piston 32 when the two lifting pistons are in contact.

[0049] Due to the configuration of the return element 33, valve 1 is held in the closed position or moved to the position without active pressurization in the lifting cylinder.

[0050] The intake valve 1 further includes an adjustment unit 4. The adjustment unit 4 is configured to be coupled to the drive unit 3, as shown in the figure.

[0051] For this purpose, the adjusting unit 4 is formed with a coupling portion 41. This portion 41 corresponds to the corresponding portion of the driving unit 3. For example, the lower end of the second lifting piston 32 also has a coupling portion. The driving-side coupling portion may, for example, have external threads, while the coupling portion 41 of the adjusting unit 4 may have internal threads. Through the engagement of the threads, especially screwing in, a robust and precise coupling between the adjusting unit 4 and the driving unit 3 can be achieved. Alternatively, the coupling can also be achieved by a screw 42, as shown here, wherein the screw head engages with the first piston 31, and the screw thread engages with the coupling portion 41.

[0052] According to an alternative embodiment, coupling may be provided, for example, by a clamping or snap-fit ​​mechanism. The invention also extends to other connection variations known in the relevant art, such as magnetic connections between two components.

[0053] The drive unit 3 is therefore coupled to the adjustment unit 4 outside the gas application unit 2 and is able to provide adjustment of the adjustment unit 4 along the adjustment axis V. The adjustment unit 4 includes a valve plate 45 at its opposite end. Therefore, the valve plate 45 can be brought into the open position in the opening direction O by the drive unit 3, in which the valve plate 45 is spaced apart from the sealing surface 24a, thus providing gas flow between the gas inlet 21 and the gas outlet 22 through the internal volume 23.

[0054] The valve plate 45 includes a seal 46, which contacts the valve seat body 24 when the valve 1 is closed, thereby providing a sealing fit between the seal 46 and the sealing surface 24a, i.e., the valve is in the closed state. At this time, the flow of fluid through the gas application unit is interrupted.

[0055] The adjustment unit 4 extends into the internal volume 23 and is adjustablely mounted outside the gas application unit 2. The valve plate 45 is disposed within the internal volume 23 and is movable along the adjustment shaft V in the closing direction S and the opening direction O.

[0056] In the closed position, the valve plate 45 is pressed against the sealing surface 24a. A plate-side seal 46, such as a sealing ring, is used to ensure an airtight seal here. The seal 46 may be disposed on the plate 45 (as shown here) or (in other embodiments) on the sealing surface 24a. The seal 46 is particularly composed of an elastomer, thermoplastic, metal, etc., and may have a shape adapted to the shape of the plate 45 (e.g., an O-ring), or may be vulcanized onto the plate 45.

[0057] The intake valve 1 further includes a flexible sealing element 25. The flexible sealing element 25 is designed as a diaphragm, particularly a metal diaphragm.

[0058] The sealing element 25 is connected to the gas application unit 2 on one side and the adjustment unit 4 on the other, thereby sealing the internal volume 23 relative to the drive unit 3. The flexibly configured diaphragm 25 thus provides a flexible seal for the internal volume 23, particularly relative to the drive unit 3, meaning the seal remains intact even when the adjustment element 4 moves. The sealing element 25 can be connected to the gas application unit 2, and / or the drive unit 3, for example, by means of a clamp.

[0059] The valve seat body 24 is formed in an annular shape around the adjusting shaft V and has an annular end face 26 facing the valve plate 45. The end face 26 extends particularly orthogonally to the adjusting shaft V.

[0060] End face 26 further includes an inner surface and an outer surface, wherein the distance of the inner surface from the adjusting shaft V is less than the distance of the outer surface from the adjusting shaft V, and the outer surface includes a sealing surface 24a. In other words, the seal 46 engages with the outer surface when the valve is closed. Therefore, the sealing line defined by this engagement is offset backward from the direct inflow area of ​​the gas inlet 21.

[0061] Figure 2 shows a top view of the valve seat body 24 of the intake valve shown in Figure 1. Here, the valve seat body 24 extends around a central recess forming the gas inlet 21. The recess has a cross-sectional area 21a orthogonal to the adjustment axis V. The inner portion region 27 and the outer portion region 28 are also shown.

[0062] The recess thus internally restricts the end face 26. In other words, the projection of the cross-sectional area 21a onto the end face 26 defines the inner boundary of the end face 26. Furthermore, the projection of the path of the seal onto the end face 26, particularly the projection of the sealing line, can define the outer boundary of the end face 26.

[0063] In the illustrated embodiment, the inner side surface is defined by the perimeter of the inner boundary of the end face 26 and the distance between the end face 26 and the valve plate surface 45a of the valve plate 45.

[0064] The outer side surface is defined by the perimeter of the outer boundary of the end face 26 and the distance between the end face 26 and the seal. This applies in particular to any open position, i.e., when the valve is not closed.

[0065] The valve seat body 24 and the valve plate 45 are formed such that the outer side surface is larger than the inner side surface, especially in the open position.

[0066] The opening position is defined, in particular, by the distance d between the valve plate 45, especially the valve plate surface 45a, and the sealing surface 24a of the valve seat body 24. This distance is particularly applicable as follows: 0.2 mm < d < 1.0 mm.

[0067] In particular, the shapes of the valve seat body 24 and the valve disc are such that the area ratio of the outer side surface to the inner side surface is in the range of 1:1 to 5:1.

[0068] The seal 46 has a sealing height h greater than 0.1 mm and protrudes from the valve plate by less than 1.0 mm. Therefore, the seal protrudes from the valve plate 45 according to its height.

[0069] Due to this advantageous configuration of the intake valve 1, precise and stable flow rate constantness can be provided, i.e., constant flow rate through the gas application unit 2.

[0070] For intake valves, it is generally crucial that the flow rate through the valve be as uniform as possible. The required range for flow rate constancy is less than 1%. In prior art intake valves, the flow-limiting portion is typically located between the seal (usually made of PFA, PA, FFKM, or FKM) and the sealing surface. Since the sealing material is typically composed of an elastic material with significant thermal expansion behavior, this can lead to uncontrolled effects on the flow rate, particularly due to changes in the thermal environment, opening / closing cycles with elastic compression and plastic compression, or other influences.

[0071] In order to overcome this drawback, the present invention is based on the idea of ​​removing the flow throttling portion of the valve from the seal.

[0072] By resetting the sealing line as described above, a flow restriction area is formed between the lower planar metal surface (valve plate surface 45a) of the valve plate 45 and the interior, specifically between the gas inlet 21. Therefore, the flow restriction area is no longer located between the seal and the sealing surface.

[0073] Due to the described ratio of the inner side surface to the outer side surface, further improved flow constantness can be provided robustly and consistently.

[0074] The requirements for intake valves are increasingly trending towards uniform and constant flow rates, which are essential for various applications (such as ALD, CVD, etching). Current diaphragm and other types of intake valves ideally provide ±2% flow rate constantness.

[0075] Due to the design of the proposed intake valve 1, the constancy of the Cv value can be significantly improved because the deformation behavior (e.g., expansion) as well as the elastic and plastic behaviors of the sealing material are removed from the flow-limiting region.

[0076] This invention has been described with reference to exemplary embodiments, but many other changes and variations may be made without departing from the scope of the invention. Therefore, the appended claims are intended to cover such changes and variations within the actual scope of the invention. [Simplified Explanation of the Diagram]

[0040] Further advantages of the present invention will become apparent from the detailed description and drawings.

[0041] FIG1 shows a cross-sectional view of an embodiment of the intake valve according to the present invention.

[0042] Figure 2 shows the valve seat body of the intake valve shown in Figure 1.

Claims

1. An inlet valve (1) for controlling fluid entry into a vacuum process chamber, the inlet valve (1) comprising: a gas application unit (2) having a gas inlet (21), a gas outlet (22), and an internal volume (23) connecting the gas inlet (21) and the gas outlet (22), wherein the gas application unit includes a valve seat body (24) having a sealing surface (24a) in the internal volume (23); an adjustment unit (4) having a valve plate (45) extending into and disposed within the internal volume (23) and having a seal (46), wherein the adjustment unit (4) is movably mounted along an adjustment shaft (V) in a closing direction (S) and an opening direction (O), and the valve plate (45) and the valve seat body (24) are configured to correspond to each other such that the seal (46) contacts the sealing surface (24a) in a closed position. A drive unit (3) coupled to an adjustment unit (4) outside the gas application unit (2) and providing adjustment of the adjustment unit (4) along the adjustment shaft (V), wherein the valve plate (45) can be brought into an open position in the opening direction (O) by the drive unit (3), in which the seal (46) is spaced apart from the sealing surface (24a) and provides a fluid passage; a flexible sealing element (25) configured as a diaphragm connected to the gas application unit (2) and the adjustment unit and isolating the drive unit (3) from the atmosphere of the internal volume (23), characterized in that: the valve seat body (24) is formed annularly around the adjustment shaft (V) and has an annular end face (26) facing the valve plate (45), The annular end face (26) includes an inner partial surface (27) and an outer partial surface (28), wherein the distance between the inner partial surface (27) and the adjusting shaft (V) is less than the distance between the outer partial surface (28) and the adjusting shaft (V), and the outer partial surface (28) includes the sealing surface (24a).

2. The intake valve (1) as claimed in claim 1, wherein the inner portion surface (27) is larger than the outer portion surface (28).

3. The intake valve (1) as claimed in claim 1 or 2, wherein both the inner portion surface (27) and the outer portion surface (28) are annular.

4. The intake valve (1) as claimed in claim 1 or 2, wherein the valve seat body (24) extends around a cylindrical recess forming the gas inlet (21) or the gas outlet (22), and the recess has a cross-sectional area (21a) orthogonal to the adjustment axis (V), and in particular, wherein a radius of the cross-sectional area (21a) includes a corner radius, wherein the corner radius is defined by a curvature path of the surface between a side surface of the recess and the end face (26).

5. The intake valve (1) as claimed in claim 4, wherein the end face (26) is located on a valve seat plane, and a projection of the cross-sectional area (21a) onto the valve seat plane defines an inner boundary of the end face, and a projection of the path of the seal (46) onto the valve seat plane, in particular a sealing line, defines an outer boundary of the end face (26).

6. The intake valve (1) as claimed in claim 5, wherein an inner side surface is defined by the distance between the inner boundary perimeter of the end face (26) and a valve plate surface (45a) of the end face (26) and the valve plate (45), and in particular, wherein the seal (46) extends around the valve plate surface (45a), and an outer side surface is defined by the distance between the outer boundary perimeter of the end face (26) and the seal (46).

7. The intake valve (1) as claimed in claim 6, wherein the valve seat body (24) and the valve plate (45) are formed such that the outer side surface is larger than the inner side surface, particularly in the open position.

8. The intake valve (1) as claimed in claim 6, wherein the valve seat body (24) and the valve plate (45) are formed such that the area ratio of the outer side surface to the inner side surface is in the range of 1:1 to 5:

1.

9. The intake valve (1) as claimed in claim 6, wherein the seal (46) is connected to the valve plate (45) and protrudes from the valve plate (45) at a sealing height h.

10. The intake valve (1) as claimed in claim 9, wherein the sealing height h is in the range of: 0.1 mm < h < 0.5 mm.

11. The intake valve (1) as claimed in claim 6, wherein in the open position, the distance d between the valve plate (45), in particular, the surface of the valve plate (45a) and the sealing surface (24a) of the valve seat body (24) is: 0.2 mm < d < 1.2 mm.

12. The intake valve (1) as claimed in claim 6, wherein the intake valve includes a return element (33), in particular a spring, wherein the return element (33) is configured to apply a return force to the adjustment unit (4) in the direction of the closing direction (S).

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