Non-elastomeric, non-polymeric, non-metallic membrane valve for semiconductor processing equipment

Abstract

Non-elastomeric, non-polymeric, non-metallic membrane valves for high vacuum applications are disclosed. Such valves function even when the fluid control side of the valve is exposed to a sub-atmospheric pressure field that can typically be used to fold / seal traditional elastomeric membrane valves.

Description

This application is a divisional application of the invention patent application with application number 202080067255.3, application date July 23, 2020, and invention name “Non-elastomeric, non-polymer, non-metallic diaphragm valve for semiconductor processing equipment”. Incorporated by Reference

[0001] The PCT request form is filed concurrently with this specification as a part of this application. Each application to which this application claims benefit or priority identified in the concurrently filed PCT request form is incorporated herein by reference in its entirety and for all purposes. Background Art

[0002] In semiconductor processing operations, it is often necessary to provide a variety of gases that may flow into a semiconductor processing chamber in various combinations, at various flow rates, and at various times. In some semiconductor processing tools, it is not uncommon for as many as 15-20 different gases (where each gas is typically controlled individually) to be supplied to the tool. Semiconductor processing tools typically include a "gas box" that houses a large number of different computer-controlled valves, mass flow controllers, and / or other gas flow components that can be controlled to provide the desired gas mixture at different times during the semiconductor processing operation.

[0003] Such gas boxes are typically assembled from relatively large (e.g., 1.5" square mounting flanges for interfacing flow components with their respective manifolds) discrete components (e.g., surface mounted valves, manifold channels, seals, etc.). Such components can be assembled into a "gas stick" for controlling each gas, which is then mounted into a cabinet to form a "gas box." The gas stick can include multiple surface mounted components, e.g., 5 to 10 such components, and a semiconductor processing tool can include multiple, e.g., 10 or 20 such gas sticks. Technical Field

[0004] This article introduces a new design for a semiconductor processing gas flow control assembly that can be used to provide a more compact valve system. Summary of the invention

[0005] Details of one or more embodiments of the subject matter described in this specification are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. The following non-limiting embodiments are considered part of this disclosure; other embodiments will also be apparent from the entire disclosure and drawings.

[0006] In some embodiments, a device may be provided that includes a substrate having one or more microfluidic valve structures, each of the one or more microfluidic valve structures including a diaphragm having a nominal diameter D d, a first side and a second side opposite the first side; a base; an aperture in the base, the aperture having a cross-sectional area A in a plane parallel to the base o ; and a boss structure having a nominal outer diameter D o and nominal inner diameter D i For each microfluidic valve structure in such a device, the diaphragm may be made of a non-elastomeric material, the boss structure may extend from the base toward the first side of the diaphragm, and when the microfluidic valve structure is in an unactuated state, the surface of the boss structure facing the diaphragm may be separated from the first side of the diaphragm by a gap of a distance d, Di may be less than or equal to 0.2·D d , A o Can be less than or equal to And the dimensions of the gap between the diaphragm, the boss structure and the microfluidic valve structure can be designed so that, when the microfluidic valve structure is transformed into an actuated state by pressurizing the second side of the diaphragm to a first pressure, a portion of the diaphragm is caused to elastically deform toward the boss structure and seal against the boss structure.

[0007] In some such embodiments, for one or more of the microfluidic valve structures, A o Can be less than or equal to And A o Can be greater than or equal to In some other such embodiments, for one or more of the microfluidic valve structures, A o Can be less than or equal to And A o Can be greater than or equal to In some other such embodiments, for one or more of the microfluidic valve structures, A o Can be less than or equal to And A o Can be greater than or equal to In some other such embodiments, for one or more of the microfluidic valve structures, A o Can be less than or equal to And A o Can be greater than or equal to In some other such embodiments, for one or more of the microfluidic valve structures, A o Can be less than or equal to And A o Can be greater than or equal to In some other such embodiments, for one or more of the microfluidic valve structures, A o Can be less than or equal to And A o Can be greater than or equal to

[0008] In some embodiments, for a first microfluidic valve structure among one or more microfluidic valve structures, the maximum distance along the first axis between the first side of the diaphragm for the first microfluidic valve structure and the surface of the protruding seat structure for the first microfluidic valve structure can be less than or equal to 40 μm, and the first axis can be perpendicular to the surface of the protruding seat structure for the first microfluidic valve structure.

[0009] In some embodiments of the device, a first side of a diaphragm of a first microfluidic valve structure used in one or more microfluidic valve structures can be subjected to a pressure equal to or less than atmospheric pressure, and a second side of the diaphragm of the first microfluidic valve structure can be subjected to atmospheric pressure when the first microfluidic valve structure is in an unactuated state.

[0010] In some embodiments of the device, the first pressure of the first microfluidic valve structure can be higher than atmospheric pressure.

[0011] In some embodiments of the device, a diaphragm for at least one of the one or more microfluidic valve structures can be made of silicon or silicon dioxide.

[0012] In some embodiments of the device, at least one of the one or more microfluidic valve structures can be made of multiple layers of silicon or silicon dioxide.

[0013] In some embodiments of the device, the device can be configured to be connected to a gas supply source so that at least one first microfluidic valve structure among the one or more microfluidic valve structures is part of a flow path within the device, and the flow path is configured to be fluidically connected to the gas supply source so that the boss structure for the first microfluidic valve structure is fluidly inserted between the gas supply source and the diaphragm for the first microfluidic valve structure.

[0014] In some such embodiments of the device, the device may further include a gas supply, and the device may be connected to the gas supply such that the boss structure for the first microfluidic valve structure is fluidly inserted between the gas supply and the diaphragm for the first microfluidic valve structure.

[0015] In some embodiments of the device, the device may further include a diaphragm layer, an actuator pumping chamber layer, and a valve pumping chamber layer. In such embodiments, the diaphragm of a first microfluidic valve structure in the one or more microfluidic valve structures may be provided by the diaphragm layer, a first side of the diaphragm layer may provide a first side of the diaphragm of the first microfluidic valve structure, a second side of the diaphragm layer may provide a second side of the diaphragm of the first microfluidic valve structure, the first side of the diaphragm layer may be bonded to the valve pumping chamber layer, the second side of the diaphragm layer may be bonded to the actuator pumping chamber layer, and the actuator pumping chamber layer may have a diameter D centered on the diaphragm of the first microfluidic valve structure. aplThe valve pumping chamber layer may have a through hole having a diameter D also centered on the diaphragm of the first microfluidic valve structure. vpl through hole, and D vpl Can be smaller than D apl . BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Various embodiments disclosed herein are illustrated by way of example and not limitation in the figures of the accompanying drawings in which like reference numerals refer to similar elements.

[0017] Figure 1 An exemplary device having a non-elastomeric, non-polymer, non-metallic microfluidic valve structure is depicted.

[0018] Figures 2 to 4 The Mach number in the orifice for a non-elastomeric, non-polymer, non-metallic microfluidic valve structure under various flow conditions is shown for two different arrangements of such valve structures.

[0019] Figure 5 Simplified perspective views of various elements of a microfluidic valve structure are provided.

[0020] Figure 6 A diagram depicting a flow splitter used to combine multiple gases together in a controlled manner.

[0021] Figure 7 An example of a dual-source splitter is depicted.

[0022] The figures herein are generally not drawn to scale, although, for example, various aspects of the figures discussed below may be drawn to scale. DETAILED DESCRIPTION

[0023] Modern semiconductor processing tools typically utilize a large number of different process gases that are introduced into the semiconductor processing chamber at different times, in different combinations, and at different flow rates. In some modern semiconductor processing tools, some reaction gases may flow in an alternating manner, wherein each sequential reaction gas stream is followed by an inert or purge gas stream that is used to remove any residues of the reactant before the subsequent reaction stream. This prevents the two reactants from mixing in the gas distribution system, which may produce undesirable side effects (although such mixing may also be desirable once the reaction gases are in the semiconductor processing chamber). A problem with the use of conventional gas control components is that the flow paths involved are typically very long and may include considerable lengths between the last controllable flow component of a given gas supply source and the point at which the gas flows into the semiconductor processing chamber. Gas trapped in such a flow path may be wasted.

[0024] In order to provide a more compact, low-cost solution for gas flow control in semiconductor processing tools, the inventors have conceived a novel non-elastic, non-polymer, non-metallic film valve. This film valve may be somewhat similar to the elastomeric microfluidic film valve used in, for example, a microfluidic box or other liquid-based analytical systems in some aspects. However, due to the operating pressures usually seen in semiconductor processing systems, and the usually highly toxic or reactive reaction gases usually handled by such systems, the microfluidic valve technology that is often used for liquid-based microfluidic processing (such as may be used for gene sequencing systems) is not suitable. For example, the elastomeric microfluidic valves that are usually used for chemical and biological analysis in microfluidic applications may be susceptible to chemical attack or gas permeation through the elastomeric film used in such valves. In addition, since most semiconductor processing chambers operate at a pressure lower than atmospheric pressure, the downstream pressure environment of such valves and therefore the side of such elastic film that provides sealing in such valves may often be under a reduced pressure compared to the other side of such film, which usually causes such elastomeric film to be deformed into a "sealed" state and difficult or impossible to reliably open.

[0025] To address such issues, the inventors have conceived a non-elastomeric, non-polymeric, non-metallic membrane valve, wherein the valve is made of layers of non-elastomeric, non-polymeric, and non-metallic materials that are bonded together to form a layered stack. Such materials [e.g., silicon (e.g., glass) or silicon dioxide (e.g., quartz)] may be selected so as to be non-reactive with gases flowing through such a valve. By avoiding the use of polymers and elastomeric materials, potential gas permeation problems through the membrane of such a valve are avoided; avoiding the use of metallic materials reduces the risk of adverse chemical reactions between the valve material and the process gases that the valve may handle.

[0026] In an elastic membrane valve, a thin elastic membrane layer is usually covered on a substrate having an inlet port and an outlet port, which can be sealed by the elastic membrane layer when the elastic membrane layer contacts the substrate. In some such valves, there may be a spacer layer between the elastomeric membrane and the substrate, which creates a gap between the elastomeric membrane and the substrate when the elastomeric membrane is in an undeformed state, thereby allowing liquid or gas to flow from one port to another port; when pressure is applied to the side of the elastic membrane opposite to the gap, the elastic membrane deflects toward the inlet port and the outlet port and contacts the inlet port and the outlet port, thereby sealing them. In other such valves, the elastic membrane can be flush with the substrate when it is not deformed, thereby sealing the inlet port and the outlet port. When one side of the elastic membrane opposite to the side sealed against the inlet and outlet is subjected to decompression, the elastic membrane can be expanded upward, thereby allowing the fluid to flow from the inlet to the outlet. When the actuating pressure (or negative pressure) is removed, the elastic membrane returns to its undeformed state. Elastic materials, such as silicone, are commonly used in such valves because such materials are liquid-tight (and most microfluidic systems are used to transmit liquids), robust and can withstand large strains without permanent deformation or rupture. This makes such elastic membranes become relatively ideal choices in most cases, because the flexibility of the elastic membrane material allows it to fit the inner surface of the valve structure, thereby achieving a very good seal to the inlet and outlet ports, and can withstand repeated actuation and relatively wide-ranging deflection. In addition to providing the elastic membrane layer of overall rigidity for the valve structure, the microfluidic valve with an elastic membrane valve can also have one or more conventionally rigid structural layers. Such rigid structural layers can be provided, for example, by non-elastomeric polymer materials (such as acrylic acid or polycarbonate) or by non-elastomeric, non-polymer materials (such as glass).

[0027] However, in the non-elastomeric, non-polymeric, non-metallic membrane valve of the present invention, the entire wet valve structure including the membrane (i.e., the portion of the valve that will be in contact with the fluid flow that the valve is designed to control) can be made of a non-elastomeric, non-polymeric, and non-metallic material. In particular, materials such as silicon (glass) or silicon dioxide (quartz) can be used, both of which are largely unreactive with most semiconductor processing gases. While such materials offer good resistance to chemical attack, both glass and quartz are very brittle materials, which severely limits their use in membrane valve situations.

[0028] The most significant problem with using non-elastomeric, non-polymeric, non-metallic materials is that such materials are generally stiffer than elastomeric materials, thereby limiting the amount of travel that a membrane made of such materials may undergo in response to a given pressure applied thereto. In addition, most of such materials that are well suited for use with the various gases used in semiconductor processing equipment, such as materials that are largely unreactive with such gases (e.g., silicon and quartz), may have very low plasticity and may break when subjected to excessive bending. In contrast, elastomeric materials, due to their elasticity and compliance, are able to withstand severe deformation without breaking.

[0029] Figure 1 Depicted are exemplary devices having non-elastomeric, non-polymer, non-metallic microfluidic valve structures. Figure 1 In the embodiment of the present invention, the device 100 is implemented in a substrate 102 in which a plurality of patterned layers 104, such as layers 104a-104g, are arranged to provide a microfluidic valve structure 106. The number and arrangement of layers 104 can be different from that depicted, and it should be understood that any arrangement of layers that can achieve a structure having similar features to those discussed herein falls within the scope of the present disclosure. The layers can be bonded together using any suitable bonding technique (e.g., diffusion bonding, fusion bonding, etc.).

[0030] The layer 104 of the substrate 102 can be configured to provide a diaphragm 108, such as a thin circular region, which can be used as a flexible membrane interposed between the actuator boost chamber 132 and the valve boost chamber 138. The diaphragm 108 can have a first side 110 and a second side 112, and a nominal diameter D vpl The valve plenum chamber 138 can be generally defined as an open volume sandwiched between the first side 110 and the base 114 and bounded by the outer perimeter of the diaphragm 108. The valve plenum chamber 138 can include a boss structure 120 that can protrude upward from the base 114 and extend toward the first side 110 of the diaphragm 108. The boss structure 120 can, for example, form a continuous wall around a central region thereof and have a surface 122 that faces the first side 110 of the diaphragm 108. In some embodiments (e.g., Figure 1 In the embodiment shown in FIG. 1 , the boss structure 120 may be an annular wall extending upward from the base 114 toward the first side 110 of the diaphragm 108 .

[0031] The orifice 118 can be located within the central region of the boss structure 120, for example, at the center of the central region of the boss structure 120, and can pass through the base 114. The orifice 118 can also be located at other locations within the central region of the boss structure 120, for example, at a location within the central region of the boss structure 120 that is not centered on the boss structure 120. The orifice 118 can fluidly connect the valve plenum 138 with a gas inlet 124, which can be used to supply semiconductor processing gas from a gas source (not shown) to the microfluidic valve structure 106. The valve plenum 138 can be fluidly connected to the outlet port 116, through which the processing gas can flow when the microfluidic valve structure 106 is in an open state and the gas inlet 124 is fluidly connected to a gas supply source for such processing gas. The orifice 118 can have any desired cross-sectional shape, although in the examples discussed herein, the orifice 118 has a circular cross-sectional shape with a diameter D.

[0032] Control of the microfluidic valve structure 106 to flex the diaphragm 108 may be provided by any suitable mechanism. For example, the actuator plenum 132 may interface with a controllable pneumatic source (e.g., a valve connected to a source of pressurized air) that allows the actuator plenum 132 to be controllably pressurized, thereby flexing and expanding the diaphragm 108 into the valve plenum 138, thereby causing the first side 110 of the diaphragm 108 to move toward the surface 122. When the diaphragm 108 is sufficiently expanded, the first side 110 of the diaphragm 108 may contact the surface 122, thereby sealing the boss structure 120 and preventing further gas flow from the orifice 118 and out of the boss structure 120. When the microfluidic valve structure is in an unactuated state, the first side 110 and the surface 122 may be separated by a gap 126 of a distance d.

[0033] Figure 1 The illustrated microfluidic valve structure can be used without regard to the direction of flow (e.g., where the gas flows in the direction illustrated, or where the gas flows in the opposite direction). However, in scenarios where the orifice 118 is fluidly inserted between the gas supply and the diaphragm 108, placing the orifice 118 upstream relative to the diaphragm 108 can provide significant advantages. As used herein, the term "fluidically inserted" refers to a first structure in a fluid flow system being positioned relative to two second structures in the fluid flow system such that a fluid flowing from one of the second structures to the other second structure must contact or flow through the first structure before reaching the other second structure. For example, a kitchen sink would be described as being fluidly inserted between the kitchen faucet of the sink and the drain pipe of the sink. Similarly, the main water shutoff valve of a house would be described as being fluidly inserted between the street water main and the internal plumbing of the house.

[0034] As gas flows through the microfluidic valve structure 106 in the manner depicted, it may encounter two general areas of increased resistance to flow. The first area is the orifice 118, which may be sized generally to act as a sonic restrictor, e.g., configured such that gas flowing through the orifice 118 develops a sonic, fully blocked flow within the orifice 118, i.e., M=1. If the size of the orifice 118 is tightly controlled, as may be achieved through photolithography, very precise orifice sizes may be achieved. This precise dimensional control, combined with fully blocked flow, may allow very precise time-based metering of gas flow through the microfluidic valve structure.

[0035] The second region is located in the annular region sandwiched between the surface 122 and the first side 110 and has a height defined by the gap 126. This region may have a height defined to a large extent by the interior (D) of the boss structure 120, such as i ) and external (D o ) size (such as inner and outer diameters) and the gap distance d, etc., which determines the flow resistance.

[0036] If the airflow direction is Figure 1 , i.e., where the diaphragm 108 is fluidly interposed between the air supply and the orifice 118, the diaphragm 108 and the annular gap between the diaphragm 108 and the surface 122 of the boss structure 120 will be upstream of the orifice. In this scenario, if choked flow occurs in the area between the diaphragm 108 and the surface 122 of the boss structure 120, the choked flow will generally not form at the downstream orifice 108. In this scenario, the orifice 118 is no longer an effective mechanism for controlling or metering gas flow and becomes redundant. The mass flow rate through the annular gap at the choked flow may be affected by a variety of factors, including the gap distance d between the diaphragm 108 and the surface 122 of the boss structure 120, the inner diameter D of the boss structure 120, and the mass flow rate through the annular gap at the choked flow. i , and the radial thickness 120(0.5·(D o -D i )). Two of these factors can be controlled by manufacturing tolerances, but it is difficult to control the gap distance d because this value may fluctuate during use depending on, for example, pressure conditions within the valve boost chamber 138 and / or atmospheric pressure conditions.

[0037] Additionally, it may generally be desirable to reduce the gap distance d overall because the smaller the distance d, the smaller the gap through which the diaphragm must be displaced in order to contact the surface 122 of the raised seal structure 120. Given the limited flexibility of non-elastomeric, non-polymeric, non-metallic materials (e.g., quartz or glass), the range of motion that a diaphragm 108 made of such materials may provide for a given size of diaphragm may be very limited.

[0038] Thus, for configurations in which the diaphragm 108 is fluidly inserted between the gas supply and the orifice 118, the microfluidic valve structure may use a large gap size, which may require a larger diameter diaphragm but avoid potential choked flow in the annular gap region, or may require a smaller gap size, which allows for a smaller diameter diaphragm but may increase the chance that choked flow will occur in the annular gap rather than the orifice 118 [one may also attempt to adjust the gap size to be “just right”, but because the gap size may fluctuate with environmental conditions (e.g., due to ambient pressure conditions), such an attempt may not produce reliable performance].

[0039] However, if Figure 1 The illustrated configuration of diaphragm 108, orifice 118, and gas supply, wherein orifice 118 is fluidly interposed between the gas supply and diaphragm 108, can produce choked flow through orifice 118 for a given flow regime with a gap distance d that is much smaller than that used in the reverse arrangement.

[0040] For example, in the exemplary orifice 118 with a diameter of d = 0.3 mm and with a diameter D i =1mm boss structure 120 with an argon flow rate of 10 standard cubic centimeters per minute (SCCM), it was observed that when the orifice was fluidly inserted between the gas source and the diaphragm, the Mach number of the flow through the orifice 118 remained relatively constant at 1 for a range of gap sizes from 0.005mm to 1mm, but in the same configuration in which the diaphragm was fluidly inserted between the gas source and the orifice, for gap sizes greater than 0.2mm, the Mach number of the flow through the orifice 118 remained similarly constant at 1, but for gap sizes between 0.005mm and 0.2mm, the Mach number dropped rapidly to 0.01. Figure 2 A graph of this behavior is shown (orifice upstream = orifice fluidly interposed between gas source and diaphragm; orifice downstream = diaphragm fluidly interposed between gas source and orifice). From this simulation data, it can be seen that positioning the orifice so that it is fluidly interposed between the gas source and the diaphragm allows the use of a gap distance d as low as ˜0.005 mm without losing choke flow in the orifice 118, whereas a diaphragm fluidly interposed between the gas source and the orifice requires a gap distance d of ˜0.2 mm or more to ensure choke flow occurs within the orifice.

[0041] Figure 3 and Figure 4 Similar graphs are depicted for the simulated data. Figure 3 Describes something like Figure 2 , except that the exemplary orifice 118 has a diameter d=0.5 mm and the boss structure 120 has a diameter D i=1 mm, and an argon flow rate of 30 standard cubic centimeters per minute (SCCM) is introduced through the microfluidic valve structure 106. Similarly, Figure 4 Describes something like Figure 2 , except that both the exemplary orifice 118 and the boss structure 120 have a diameter D i and D = 1 mm, and an argon flow rate of 120 standard cubic centimeters per minute (SCCM) is introduced through the microfluidic valve structure 106. In both additional cases, similar characteristics can be observed, namely, positioning the orifice so that it is fluidly inserted between the gas source and the diaphragm allows the use of a much smaller gap distance d, such as 0.01 mm or 0.05 mm, while still maintaining a blocked flow condition in the orifice 118, while positioning the diaphragm so that it is fluidly inserted between the gas source and the orifice requires maintaining the gap distance d to be, for example, 2.5 mm or higher (for Figure 3 for the scene; Figure 4 scenario, for the simulated scenario, fully blocked flow never really develops).

[0042] In the non-elastomer, non-polymer, non-metal microfluidic valve structure discussed herein, the film / diaphragm of the microfluidic valve structure can be configured to have a very small actuation gap (i.e., the distance that the diaphragm must move through) to seal the orifice of the valve structure and hinder fluid flow. The actuation gap can generally be driven by the size of the diaphragm, wherein a larger diaphragm allows a larger displacement and therefore allows a larger actuation gap. For example, a microfluidic valve structure with a silicon-based diaphragm having an effective diameter of 5 mm can be configured to allow only a deflection of 0.04 mm before the orifice of the sealing valve structure. However, as previously described, for a microfluidic valve structure intended to act with a semiconductor processing device (wherein the gas flowing through the microfluidic valve structure can flow into an environment below atmospheric pressure), the diaphragm can be exposed to a pre-existing pressure difference when in an unactuated state, for example, a pressure below atmospheric pressure on a first side of the diaphragm, and atmospheric pressure (or a pressure below atmospheric pressure on a first side of the diaphragm higher than the pressure below atmospheric pressure) on a second side of the diaphragm. Thus, the diaphragm may be in a partially expanded or flexed state even without active actuation - actuation by increasing pressure on the second side of the diaphragm may simply cause the diaphragm to deflect or expand further until the first side of the diaphragm contacts the boss structure.

[0043] This problem is unique to microfluidic valves in the context of semiconductor processing tools, and imposes some practical limitations on such valves that are not encountered in normal microfluidic systems (e.g., microfluidic systems for processing liquids that can be used for genetic, chemical or biological liquid analysis). For example, the diaphragm deflection as a function of constant pressure increases nonlinearly with increasing diaphragm diameter. Therefore, increasing the diaphragm diameter can provide a larger potential travel margin in the diaphragm, but at the expense of an increase in the "static" deflection due to atmospheric pressure, which acts to reduce the size of the gap between the diaphragm 108 and the surface 122 of the available boss structure, and can also cause increased stress in the diaphragm, which may lead to earlier failure. Another disadvantage of increasing the diaphragm diameter is that fewer microfluidic valve structures can be manufactured at one time. As previously described, photolithography can be used to manufacture the layers of the microfluidic device described herein. In this technology, a large number of microfluidic valve structures can be manufactured on a single wafer (e.g., a silicon wafer). This manufacturing technology is expensive to implement and becomes more cost-effective when a large number of microfluidic valve structures are manufactured simultaneously on a wafer. Therefore, since fewer microfluidic valve structures can fit on a wafer of a given size as the diameter size of the diaphragm 108 increases, it may be beneficial in many embodiments to reduce or minimize the diameter of the diaphragm. In particular, the inventors have discovered that, in some embodiments, reducing the diameter D vpl The limit is to a value of about one centimeter or less, such as 10mm, 9mm, 8mm, 7mm, 6mm, 5mm, 4mm, or 3mm, 2mm, 1mm, or values ​​therebetween.

[0044] The diameter of the diaphragm and the properties of the material used to provide the diaphragm can effectively determine the maximum amount of travel that the diaphragm can provide (without failure) when the second side of the diaphragm is subjected to a given pressure environment. This maximum amount of travel can in turn determine the size of the gap distance d, taking into account any pre-actuation displacement due to atmospheric pressure effects if necessary. For example, a microfluidic valve structure with a 5mm diameter and an 85μm thick diaphragm can have a gap distance of 0.040mm, although this gap distance is conservative and in some cases a larger gap distance can be used, such as up to 0.125mm in some embodiments.

[0045] The orifice can generally be selected based on the gas flow characteristics desired for a given semiconductor processing tool using the microfluidic valve structure. The size of the orifice can be selected to produce a choked flow therethrough within the range of flow rates required for semiconductor processing operations provided by the semiconductor processing tool. For example, an orifice diameter of 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm, or values ​​therebetween, can be used in various embodiments.

[0046] The size of the boss structure can be selected based on the orifice size, gap distance and diaphragm diameter. For example, the inner diameter Di of the boss structure can be selected to be less than or equal to 0.2·D d , where D d is the nominal diameter of the diaphragm, e.g. D vpl The inner diameter Di, gap distance d and orifice diameter D can be selected so that A o Less than or equal to Among them A o is the cross-sectional area of ​​the orifice, for example, for a circular orifice, In various embodiments, and or

[0047] The various layers of the microfluidic valve structures disclosed herein can be configured in a variety of different ways. For example, some embodiments can feature a layer having a through-hole feature, which is then bonded to a layer that does not have a corresponding through-hole feature to form a blind hole or internal chamber within the layer stack. In other embodiments, the blind hole can be formed directly in the layer without any bonding, such as by etching or mechanically processing the feature to a depth less than the thickness of the layer. The thickness of the various layers can be selected as required for a particular application. For example, in some microfluidic valve structures, the thickness of the diaphragm can be between 15 μm and 120 μm, for example, a thickness of approximately 0.085 mm; of course, the thickness of the diaphragm at least partially determines the stroke that the diaphragm can achieve during actuation.

[0048] In some embodiments, the thickness of the base may be between 100 μm and 1000 μm, for example, 0.725 mm thick; the thickness of the base may be selected to structurally support the boss structure and withstand operating pressures within the valve structure. However, the thickness of the base may also determine the length of the orifice; an orifice that is too long may experience an undesirable increase in flow resistance.

[0049] Figure 5 A simplified perspective view of the various elements of the microfluidic valve structure discussed above is provided. Figure 5 In the figure, the diameter D is shown. d The diaphragm 508 is provided with a boss structure 520 having a surface 522 facing the first side 510 of the diaphragm 508 and separated from the first side 510 by a gap of a distance d. Figure 5 The top side of the diaphragm 508 may be pressurized to drive the diaphragm 508 into contact with the surface 522 of the boss structure 520. The boss structure 520 may have an inner diameter D i and outer diameter D o , the inner diameter D i and outer diameter Do can each define an area A together with the gap distance d g1 and A g2 The cylindrical reference surface of , for example, is defined by multiplying the circumference associated with each corresponding diameter by the gap distance d. The orifice 518 can be located in the base of the microfluidic valve structure (not shown); the orifice can have a cross-sectional area A o Generally speaking, A g1 Can be selected as greater than A o twice as much.

[0050] In some embodiments, the diaphragm 108 can be implemented in a particular manner, such as with different diameters for defining the first side 110 and the second side 112. For example, as shown in FIG. AA, the first side 110 of the diaphragm 108 and the valve plenum chamber 138 can be formed by a nominal diaphragm diameter D vpl and the second side 112 of the diaphragm 108 and the actuator plenum 132 may be defined by a nominal actuator plenum diameter D apl It can be seen that the actuator boost chamber 132 can be disposed in an actuator boost chamber layer 134 (layer 140a), which can have a diameter D vpl Similarly, the valve plenum 138 may be disposed in a valve plenum layer 140 (layer 140c), which may have a diameter D apl By avoiding D vpl and D apl The same structure can significantly reduce stress at the corners where layers 140a and 140c meet layer 140b providing diaphragm 108, thereby providing more robust valve operation and a lower chance of valve failure.

[0051] Non-elastomeric, non-polymer, non-metallic microfluidic valve structures such as those disclosed herein may be used in semiconductor processing equipment in a variety of ways. Figure 6 and 7 Exemplary embodiments in which such microfluidic valve structures may be used are depicted. Figure 6 A diagram depicting a flow splitter used to combine multiple gases together in a controlled manner. Figure 6 In the embodiment, a plurality of gas sources 630a-630f are provided. For example, each gas source 630 can receive gas from a pressurized gas source or container. The gas sources 630 can each be fluidly connected to an inlet channel 642, for example, gas source 630a can be fluidly connected to inlet channel 642a, gas source 630b can be fluidly connected to inlet channel 642b, and so on. Each inlet channel 642 can also be connected by a corresponding plurality of non-elastic, non-polymer, non-metallic microfluidic valve structures 606 (in Figure 6Only three are marked, but it is obvious that each inlet channel 642 has seven such microfluidic valve structures 606) connected to the corresponding branch channel 646 fluid. In this example, each inlet channel is connected to the seven microfluidic valve structures, but it should be understood that more or fewer such microfluidic valve structures can be provided, and two or more gas supply sources 630 can be connected to their respective branch channels 642 through different numbers of microfluidic valve structures 606 (rather than each having the same number of microfluidic valve structures). The branch channels 646 can all converge at a common outlet channel 644, which can lead to a mixed gas outlet 648.

[0052] In such Figure 6 In the flow divider shown, the microfluidic valve structure 606 can be maintained in a closed state, such as by pressurizing the diaphragm using a pneumatic valve and pressurized air, thereby preventing the process gas provided by the gas source 630 from flowing into the branch channel 646. If a specific combination of process gases at a specific mixing ratio and / or flow rate is required, an appropriate number of microfluidic valve structures 606 for each of these gas supply sources 130 can be actuated to an open state, thereby allowing these process gases to flow into their respective branch channels 646 and the common outlet channel 644. For example, if a ratio of 1:3:7 of gases from the gas supply sources 630a, 630c, and 630d, respectively, is required, then one microfluidic valve structure 606 fluidly connecting the inlet channel 642a and the branch channel 646a can be opened, three microfluidic valve structures 606 fluidly connecting the inlet channel 642c and the branch channel 646c can be opened, and seven microfluidic valve structures 606 fluidly connecting the inlet channel 642d and the branch channel 646d can be opened. Assuming that the orifice of each microfluidic valve structure 606 is the same size, a fully blocked flow provided through each orifice of each open microfluidic valve structure can provide the desired gas ratio.

[0053] Figure 7 An example of a dual-source current splitter is depicted. Figure 7In the embodiment of the present invention, two gas sources 730a and 730b are connected to respective pressurized gas sources and supply corresponding processing gases to inlet channels 742a and 742b, respectively. Each inlet channel 742 is connected to a common outlet channel 744 fluid by a plurality of corresponding microfluidic valve structures 706a and 706b. The common outlet channel 744 leads to a mixed gas outlet 748. In this particular example, instances A and B of the microfluidic valve structure 706a are in an open state (which can be a default unactuated state in some embodiments), while instances C, D, E, F and G of the microfluidic valve structure 706a are in a closed state. Similarly, instances A, B, C and D of the microfluidic valve structure 706b are in an open state, while instances E, F and G of the microfluidic valve structure 706a are in a closed state. Therefore, the mixing ratio of the gas from the gas source 730a to the gas from the gas source 730b can be 1:2.

[0054] It will be appreciated that many other embodiments of microfluidic valve structures can be implemented using the microfluidic valve structures disclosed in the present application. For example, one such embodiment is a semiconductor processing showerhead, for example, a gas distributor that distributes processing gases on a semiconductor wafer during a processing operation. A showerhead typically has a large number (e.g., hundreds or thousands) of gas distribution ports distributed on the underside of the showerhead - the diameter of this area is typically at least as large as the wafer being processed. The flow of processing gas through the showerhead is typically regulated by a valve located outside the showerhead. For valves located outside, there may be a significant delay, such as several seconds, between opening the valve and releasing the gas flowing therethrough through the showerhead [this delay is caused by the need for the gas to flow out of the valve, through the showerhead, and through the gas distribution ports on the underside (or panel) of the showerhead]. A large amount of waste gas may also accumulate in the showerhead after each gas flow.

[0055] As discussed in U.S. Patent Application No. 15 / 346,920 filed on November 11, 2016, a more efficient showerhead can be provided by implementing a microfluidic valve structure (such as those disclosed herein) within the showerhead (e.g., at each gas distribution port). In this way, the flow path from each microfluidic valve structure to the gas distribution port can generally be as short as possible, thereby reducing the transmission time of the gas released thereby. In some embodiments, each microfluidic valve structure, or a group of such valve structures, can be individually actuatable, thereby allowing a group of valves to be actuated or not actuated and allowing different gas flow patterns to be provided by the showerhead. It should be understood that the microfluidic valve structures discussed herein can be used to provide valves for active showerheads discussed in U.S. Patent Application No. 15 / 346,920, the contents of which are incorporated herein by reference in their entirety.

[0056] As described above, the microfluidic valve structures discussed herein can be actuated by any suitable mechanism (e.g., by actuation of a pneumatic valve that can be used to pressurize the diaphragm of such a valve structure). Such a pneumatic valve can be controlled by a controller of a semiconductor processing tool. The controller can be part of a system that can include semiconductor processing equipment, including one or more processing tools, one or more chambers, one or more platforms for processing, and / or specific processing components (wafer bases, gas flow systems, etc.). These systems can be integrated with electronic devices to control their operations before, during, and after processing semiconductor wafers or substrates. Electronic devices can be referred to as "controllers", which can control various components or sub-components of one or more systems. Depending on the processing requirements and / or the type of system, the controller can be programmed to control any process disclosed herein, as well as various parameters that affect semiconductor processing, such as the delivery of processing gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, position and operation settings, wafer conveyors and / or other conveying tools in and out of the tool, and / or load locks connected or engaged with a specific system.

[0057] In general, a controller can be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. The integrated circuit can include a chip in the form of firmware that stores program instructions, a digital signal processor (DSP), a chip defined as an application specific integrated circuit (ASIC), and / or one or more microprocessors, or a microcontroller that executes program instructions (e.g., software). The program instructions can be instructions sent to the controller in the form of various individual settings (or program files) that define operating parameters for performing a specific process on or for a semiconductor wafer or system. In some embodiments, the operating parameters can be part of a recipe defined by a process engineer to complete one or more processing steps during the manufacture of one or more (kinds of) layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0058] In some implementations, the controller may be part of or coupled to a computer that is integrated with the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the "cloud" or all or part of a wafer fab host system that may allow remote access to wafer processing. The computer may enable remote access to the system to monitor the current progress of a manufacturing operation, check the history of past manufacturing operations, check trends or performance criteria for multiple manufacturing operations, change parameters of a current process, set processing steps to follow the current process, or start a new process. In some examples, a remote computer (e.g., a server) may provide a process recipe to the system via a network (which may include a local network or the Internet). The remote computer may include a user interface that enables input or programming of parameters and / or settings, which are then sent from the remote computer to the system. In some examples, the controller receives instructions in the form of data that specify parameters for each processing step to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control. Thus, as described above, the controller may be distributed, for example, by including one or more discrete controllers networked together and working toward a common purpose (e.g., the process and control described herein). An example of a distributed controller for such a purpose is one or more integrated circuits on a chamber communicating with one or more integrated circuits remotely (e.g., at a platform level or as part of a remote computer), which combine to control the process on the chamber.

[0059] Exemplary systems may include, but are not limited to, plasma etching chambers or modules, deposition chambers or modules, spin rinse chambers or modules, metal plating chambers or modules, cleaning chambers or modules, chamfer edge etching chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, atomic layer deposition (ALD) chambers or modules, atomic layer etching (ALE) chambers or modules, ion implantation chambers or modules, track chambers or modules, and any other semiconductor processing system that may be associated with or used in the manufacture and / or preparation of semiconductor wafers.

[0060] As described above, depending on one or more processing steps to be performed by the tool, the controller can communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout the factory, a host computer, another controller, or tools used in material transport to transport wafer containers to and from tool locations and / or load ports in a semiconductor manufacturing facility.

[0061] As used herein, the term "wafer" may refer to a semiconductor wafer or substrate or other similar types of wafers or substrates. As used herein, a wafer station may refer to any location in a semiconductor processing tool where a wafer may be placed during any of a variety of wafer handling operations or wafer transfer operations. Wafer support is used herein to refer to any structure in a wafer station configured to receive and support a semiconductor wafer, such as a pedestal, electrostatic chuck, wafer support rack, etc.

[0062] It should also be understood that the use of ordinal indicators [e.g., (a), (b), (c), ...] herein is for organizational purposes only and is not intended to convey any particular order or importance of the items associated with each ordinal indicator. For example, "(a) obtaining information about speed and (b) obtaining information about position" would include obtaining information about position before obtaining information about speed, obtaining information about speed before obtaining information about position, and obtaining information about position and obtaining information about speed simultaneously. However, there may be situations where some of the items associated with an ordinal indicator may inherently require a particular order, for example, "(a) obtaining information about speed, (b) determining a first acceleration based on the information about speed, and (c) obtaining information about position"; in this example, (b) would require the execution of (a) because (b) depends on the information obtained in (a) - however, (c) may be executed before or after (a) or (b).

[0063] It should be understood that the use of the word "each," if used herein, such as in the phrase "for each <item> of one or more <items>" or "each <item>," should be understood to include both single-item groups and multi-item groups, i.e., the use of the phrase "for each of..." means that it is used in a programming language to refer to each item in any group of items being referred to. For example, if the group of items referred to is a single item, then "each" will refer only to that single item (although dictionary definitions of "each" often define the term as "each of two or more things"), and does not mean that there must be at least two of those items. Similarly, when a selected item may have one or more sub-items and one of those sub-items is selected, it will be understood that in the case where the selected item has one and only one sub-item, the selection of that one sub-item is inherent in the selection of the item itself.

[0064] It should also be understood that reference to a plurality of controllers that are generally configured to perform various functions is intended to encompass situations in which only one controller is configured to perform all of the functions disclosed or discussed, as well as situations in which various controllers each perform a subset of the functions discussed. For example, an auto-calibration wafer may include a controller that is configured to control the operation of various sensors on the auto-calibration wafer and transmit data therefrom to another controller associated with a semiconductor processing tool; the semiconductor processing tool controller may then analyze such data to determine various operating parameters for use with the semiconductor processing tool.

[0065] Various modifications to the embodiments described in this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Therefore, the claims are not intended to be limited to the embodiments shown herein, but are to be given the broadest scope consistent with the disclosure, the principles and novel features disclosed herein.

[0066] Certain features described in this specification in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination. In addition, although features may be described above as functioning in certain combinations and even initially claimed as such, in some cases one or more features of a claimed combination may be removed from the combination, and a claimed combination may be directed to a sub-combination or a variation of a sub-combination.

[0067] Similarly, although operations are depicted in a particular order in the accompanying drawings, this should not be understood as requiring such operations to be performed in the particular order shown or in sequence, or performing all the operations shown to achieve the desired result. In addition, the accompanying drawings may schematically depict another exemplary process in the form of a flow chart. However, other operations not depicted may be incorporated into the schematically shown exemplary process. For example, one or more additional operations may be performed before, after, at the same time, or between any of the operations shown. In some cases, multitasking and parallel processing may be advantageous. In addition, the separation of various system components in the above-mentioned embodiments should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. In addition, other embodiments are within the scope of the appended claims. In some cases, the actions described in the claims may be performed in different orders and still achieve the desired results.

Claims

1. A device comprising: A substrate having one or more microfluidic valve structures, each of the one or more microfluidic valve structures comprising: The diaphragm has a nominal diameter D d , a first side and a second side opposite to the first side; base; An aperture in the base having a cross-sectional area A in a plane parallel to the base o ; as well as The boss structure has a nominal outer diameter D o and nominal inner diameter D i , where, for each microfluidic valve structure: The diaphragm is made of a non-elastomeric material, The boss structure extends from the base toward the first side of the diaphragm, When the microfluidic valve structure is in an unactuated state, the surface of the boss structure facing the diaphragm is separated from the first side of the diaphragm by a gap of a distance d, D i Less than or equal to 0.2·D d , A o Less than or equal to and The dimensions of the diaphragm, the boss structure, and the gap of the microfluidic valve structure are such that when the microfluidic valve structure is transformed into an actuated state by pressurizing the second side of the diaphragm to a first pressure, a portion of the diaphragm is caused to elastically deform toward the boss structure and seal against the boss structure.

2. The device according to claim 1, wherein: For one or more of the microfluidic valve structures, A o Less than or equal to And A o Greater than or equal to 3. The device according to claim 1, wherein: For one or more of the microfluidic valve structures, A o Less than or equal to And A o Greater than or equal to 4. The device according to claim 1, wherein: For one or more of the microfluidic valve structures, A o Less than or equal to And A o Greater than or equal to 5. The device according to claim 1, wherein: For one or more of the microfluidic valve structures, A o Less than or equal to And A o Greater than or equal to 6. The device according to claim 1, wherein: For one or more of the microfluidic valve structures, A o Less than or equal to And A o Greater than or equal to 7. The device according to claim 1, wherein: For one or more of the microfluidic valve structures, A o Less than or equal to And A o Greater than or equal to 8. The device according to claim 1, wherein: For a first microfluidic valve structure of the one or more microfluidic valve structures: a maximum distance along a first axis between the first side of the diaphragm for the first microfluidic valve structure and the surface of the boss structure for the first microfluidic valve structure is less than or equal to 40 μm, and The first axis is perpendicular to the surface of the boss structure for the first microfluidic valve structure.

9. The device according to claim 1, wherein: The first side of the diaphragm for a first microfluidic valve structure among the one or more microfluidic valve structures is subjected to a pressure equal to or lower than atmospheric pressure, and the second side of the diaphragm of the first microfluidic valve structure is subjected to atmospheric pressure when the first microfluidic valve structure is in an unactuated state.

10. The device of claim 9, wherein the first pressure of the first microfluidic valve structure is higher than atmospheric pressure.

11. The device of claim 1, wherein the diaphragm for at least one of the one or more microfluidic valve structures is made of silicon or silicon dioxide.

12. The device of claim 1, wherein at least one of the one or more microfluidic valve structures is made of multiple layers of silicon or silicon dioxide.

13. A device according to claim 1, wherein the device is configured to be connected to a gas source so that at least a first microfluidic valve structure among the one or more microfluidic valve structures is part of a flow path within the device, and the flow path is configured to be fluidically connected to the gas supply source so that the boss structure for the first microfluidic valve structure is fluidly inserted between the gas supply source and the diaphragm for the first microfluidic valve structure.

14. The device according to claim 13 further comprises the gas supply source, wherein the device is connected to the gas supply source so that the boss structure for the first microfluidic valve structure is fluidly inserted between the gas supply source and the diaphragm for the first microfluidic valve structure.

15. The apparatus according to claim 1, further comprising: Diaphragm layer; Actuator plenum layer; and Valve plenum layer, wherein: The diaphragm of a first microfluidic valve structure of the one or more microfluidic valve structures is provided by the diaphragm layer, the first side of the diaphragm layer providing the first side of the diaphragm of the first microfluidic valve structure, The second side of the membrane layer provides the second side of the membrane of the first microfluidic valve structure, The first side of the diaphragm layer is bonded to the valve pumping chamber layer, the second side of the diaphragm layer being bonded to the actuator pumping chamber layer, The actuator pumping chamber layer has a diameter D apl a through hole centered on the diaphragm of the first microfluidic valve structure, The valve plenum layer has a diameter D vpl The through hole is also centered on the diaphragm of the first microfluidic valve structure, and D vpl Less than D apl .

Images