Gas diffuser housings, devices, and related methods

Abstract

Directional gas diffuser devices and housing components thereof, systems including the gas diffuser devices, methods of using the gas diffuser devices, and methods of manufacturing the gas diffuser devices are described.

Description

[Technical Field]

[0001] The present specification relates to gas diffuser devices, and in particular to directional gas diffuser devices and housing components thereof, systems including gas diffuser devices, methods of using gas diffuser devices, and methods of manufacturing gas diffuser devices. [Background technology]

[0002] Various industrial processes and manufacturing systems involve process steps and equipment that distribute gases into the enclosed interior spaces of chambers used to process, store, transport, or handle one or more semiconductor wafers during manufacturing. Exemplary systems include systems for processing semiconductor and microelectronic devices that supply gases used in cleaning, etching, or material deposition steps (e.g., chemical vapor deposition, atomic deposition, etc.). Gases supplied to these systems include reactive gases, corrosive gases such as hydrogen bromide (HBr) and other halide-containing gases, and inert gases.

[0003] Other systems include equipment used to contain, handle, transport, or move multiple semiconductor wafers; examples are devices called wafer transfer chambers, wafer carriers ("FOUPs"), etc. These equipment include an enclosed interior space adapted to contain multiple semiconductor wafers while the wafers are being processed. The enclosed space of the device contains the wafers and may contain an atmosphere that is evacuated (i.e., under reduced pressure) or contains a gas other than air, e.g., an inert gas.

[0004] As an example, a wafer transfer station is a device that includes a chamber with a sealed interior that is evacuated during use while multiple in-process semiconductor wafers are held therein. Before opening the vacuum chamber to remove the wafers, gas may be returned to the sealed interior to equalize the pressure therein with the external (ambient) pressure. The gas may be an inert gas and is generally introduced into the sealed interior through a device called a diffuser. The diffuser introduces the gas into the interior of the transfer station in a steady and diffused manner to avoid disturbing any contaminant particles that may be present inside, which, if disturbed, may settle on the surface of the wafers. Another device including an enclosed space adapted to contain multiple semiconductor wafers is a wafer carrier, sometimes referred to as a "FOUP," which may stand for "Front Opening Unified Pod" or "Front Opening Universal Pod." A FOUP contains multiple semiconductor wafers in an enclosed interior for transporting those wafers. During use, while containing the wafers inside the chamber, the interior is filled with an inert gas atmosphere, as opposed to an air atmosphere. The inert gas is typically added to the enclosed chamber interior by a diffuser. The diffuser introduces the inert gas into the interior of the wafer carrier as a steady and diffused flow to avoid disturbing contaminant particles that may be present inside, which, if disturbed, may settle on the surface of the wafers. Summary of the Invention

[0005] A diffuser housing for a directional gas diffuser is described, which is useful for distributing gaseous source materials within an enclosed interior, such as a chamber of a semiconductor handling or processing device, or other reaction chamber, vacuum chamber, etc. Also described are a diffuser assembly including the housing and other components of the diffuser, such as a diffuser membrane, methods of making the housing and diffuser assembly, a processing system including the diffuser assembly, and methods of using the housing and diffuser assembly.

[0006] According to an exemplary diffuser housing, the housing comprises an elongated body including an inlet at one end, a closed second end, and a diffuser outlet (e.g., an "opening") extending across the face of the body along a length between the inlet end and the closed end. A channel within the housing extends along the length between the inlet end and the closed end and connects to the inlet and the diffuser outlet. The channel can have varying dimensions along the length of the diffuser housing to improve flow uniformity through the diffuser outlet. For example, the channel can have varying cross-sectional area, depth, or both at different positions along the length when viewed in a direction along the longitudinal axis. The cross-sectional area or depth of the channel can be reduced at positions closer to the closed end to improve gas flow uniformity through the diffuser outlet along the length.

[0007] The described diffuser body can be prepared by any useful method, and some useful or currently preferred methods include additive manufacturing techniques, including methods commonly referred to as "3D printing" techniques. This method generally involves a series of individual layer-forming steps that sequentially form multiple layers of a solidified feedstock composition derived from layers of feedstock to form the diffuser housing. Some specific examples of general types of additive manufacturing techniques include what are commonly referred to as "powder-bed" additive manufacturing methods, including various "binder jet printing" techniques. Other examples include stereolithography (SLS) and "feedstock dispensing methods" (FDM). Still other examples are referred to as "laser metal deposition," "direct metal deposition," and "direct energy deposition." The described diffuser body can be prepared by any of these additive manufacturing methods, as well as others now known or that may be developed in the future.

[0008] In one aspect, the present invention relates to a directional gas diffuser including an elongated housing having an inlet end, a closed end, a length between the inlet end and the closed end, an opening on a front side of the housing extending along the length, and a channel extending between the inlet end and the closed end. The channel is defined along the length by the opening extending along the front side, an elongated back side, and an elongated side. The channel has a length, a width, a depth, and a varying cross-sectional area along the channel length.

[0009] In another aspect, the invention relates to a directional gas diffuser that includes an elongated housing, the housing including an inlet end with an inlet, a closed end, a length between the inlet end and the closed end, an opening on a front side of the housing extending along the length, and an interior channel extending between the inlet and the closed end, the channel being defined along the length by the opening on the front side, an elongated, non-porous back surface, and an elongated, non-porous side surface.

[0010] In yet another aspect, the invention relates to a method of making the described directional gas diffuser by additive manufacturing, the method including forming a first feedstock layer on a surface, the first feedstock layer comprising inorganic particles, forming a solidified feedstock from the first feedstock layer, forming a second feedstock layer on the first feedstock layer, the second feedstock layer comprising inorganic particles, and forming a second solidified feedstock from the second feedstock layer, wherein the solidified feedstock layer is part of the directional gas diffuser. [Brief explanation of the drawings]

[0011] [Figure 1] 1A-1C illustrate an example of the described diffuser housing and diffuser assembly. [Figure 2A-2B] FIG. 1 illustrates an example of the chamber and diffuser assembly described. [Figure 3A] FIG. 2 is a side perspective view showing an example of the diffuser housing described. [Figure 3B] 1 is a diagram (plan view) showing an example of the diffuser housing to be described. FIG. [Figure 3C] FIG. 1 is a side cutaway view of an example of an illustrated diffuser housing. [Figure 4] FIG. 2 is a side cutaway view of an illustrated diffuser housing. [Figure 5A-5B] 10A-10C show a comparison of gas flow through the described diffuser devices. [Figure 6] FIG. 1 is a photograph showing laminar flow of water through the described diffuser. DETAILED DESCRIPTION OF THE INVENTION

[0012] All figures are schematic and not necessarily to scale.

[0013] The present disclosure relates to a diffuser housing (or simply "housing") for a directional gas diffuser useful for distributing gaseous source material (e.g., "reagent gas") within an enclosed interior of a semiconductor processing chamber or other type of vacuum chamber, reaction chamber, etc. The present disclosure also relates to a diffuser assembly including the housing and other components of the diffuser, such as a diffuser membrane, to methods of making the housing and diffuser assembly, to processing systems including the diffuser assembly, and to various methods of using the housing and diffuser assembly.

[0014] The described diffuser assembly is of a type sometimes referred to as a "directional diffuser," distinct from other common types of diffusers, such as "showerhead" diffusers, "tube" diffusers, "disk" diffusers, and "plate" diffusers. Directional diffusers have a configuration that includes an elongated diffuser body between two ends of an elongated diffuser housing, one end being a fluid inlet end and the second end being a closed end. Directional diffusers include a diffuser opening on only one side of the diffuser body that extends along the length of the elongated diffuser housing between the inlet end and the closed end, with a diffuser membrane covering the opening. The diffuser membrane is porous and semi-resistant to gas flow, allowing gas under moderate pressure to flow through it as a dispersed or "diffused" stream directed from only one side of the housing. Gas flows into the diffuser housing at the inlet end, flows along the length of the housing, then through the membrane transverse to the flow through the housing and exits the housing laterally from only a portion of the housing (e.g., from one side), e.g., perpendicular to the direction of gas flow into and within the housing. On the remainder of the housing (the side not including the opening and diffuser membrane), the housing includes a non-porous surface that encloses an internal channel that extends from the inlet along the length of the housing to a closed end and contacts the diffuser membrane.

[0015] A gaseous fluid can flow into the inlet and into the inlet end of the internal channel. The fluid then flows along the length of the internal channel, which also flows along the length of a diffuser membrane held in a length-wise opening on one side of the housing. As the fluid flows within the internal channel along the length of the housing, a portion of the fluid also passes laterally (relative to the direction of flow along the channel) through the diffuser membrane throughout its length. The diffuser membrane functions as a diffuser outlet extending along the length of the diffuser, allowing gas flowing along the length of the diffuser body to flow laterally (perpendicular to the length-wise direction of the internal channel) within the internal channel and exit the housing on one (and only one) side of the diffuser housing; the flow of gaseous fluid from the housing is primarily in a direction perpendicular to the flow of fluid through the internal channel of the housing, with the fluid entering the channel at the inlet.

[0016] The diffuser is described as "directional" because the transverse flow occurs directionally relative to the circumference of the diffuser. The diffuser has a circumference when viewed lengthwise. The transverse flow does not occur in all directions around the circumference (i.e., all 360 degrees around the circumference). Instead, the openings in the housing through which the gas flows span a portion of the circumference, sometimes referred to as a "side" of the housing. The portion of the housing where the transverse flow occurs may be less than half the entire circumference; for example, the flow may occur over less than 180 degrees of the circumference, e.g., between 10 and 170 degrees, or between 20 and 150 degrees, or between 40 and 120 degrees.

[0017] A benefit of directional flow from a diffuser over less than the entire perimeter is the ability to control the direction and placement of direct gas flow into the chamber. The flow can be directed for the purpose of avoiding direct flow of gas into areas of the chamber where particulate contamination may be present. Direct flow of gas toward particle-laden areas of the chamber can disturb and disperse particles within the chamber, which is preferably avoided. More generally, the flow can be directed to provide uniform or sufficient contact of the gas with the wafer or workpiece within the chamber.

[0018] The directional diffuser has a length dimension between the inlet end and the closed end, a width perpendicular to the length, and a depth perpendicular to the length and width. The directional diffuser is elongated and has a length greater than its width and greater than its depth. Exemplary directional diffusers can have a length that is at least 2, 4, 5, 10, 12, 15, 20, or 30 times the depth or width, or both, measured at the exterior surface of the housing.

[0019] Referring to FIG. 1 , an exemplary directional diffuser 100 is shown. The directional diffuser 100 includes a housing 112 having a length (L), a width (w), and a depth (d). The housing 112 includes an inlet 102 at an inlet end 106, a second end (“closed end”) 104, and a length L extending between the inlet end 106 and the closed end 104. On a front side 108 (top side, as shown) of the housing 112, an opening 118 extends along the length L and width w between the inlet end 106 and the closed end 104. As shown, two separate longitudinal openings 118 are shown, but the two openings 118 may alternatively be formed as a single opening unobstructed along the length L. A porous diffuser membrane 120 is retained within each of the two openings 118.

[0020] More specifically, inlet 102 opens into an interior channel (not shown) defined by a porous diffuser membrane 120 on one side and by three elongated, non-porous sidewalls on three other sides, including a (not visible) left sidewall 114, a right sidewall 116, and a (not visible) bottom or back sidewall 122. Each sidewall 114, 116, and 122 is non-porous, i.e., impermeable to gas flow, and each sidewall 114, 116, and 122 includes a non-porous inner surface that defines an interior channel extending along the length L of housing 100.

[0021] Generally, when positioned for use inside an enclosed chamber ("chamber" or "enclosed chamber") of a semiconductor handling or processing device, the directional diffuser extends from a sidewall, top, or bottom of the chamber, with the length of the diffuser extending from the sidewall, top, or bottom into the interior space of the chamber. Optionally, the directional diffuser may be mounted within the chamber on a rotational mount that allows the diffuser to be rotated about an axis extending along the length of the diffuser.

[0022] 2A, a side view of a chamber 220 including a directional diffuser 200 as described herein is shown. The directional diffuser 200 is mounted within the enclosed interior space 220 of the chamber 202 and is used to distribute a uniform flow of gas from a gas source (not shown) to the interior 220 of the chamber 202, which contains the wafer 218.

[0023] Chamber 202 includes a bottom 206, a top 204, and (left and right) sidewalls 208 and 210 that define a sealed chamber interior 220. Directional diffuser 200 includes a housing 230, an inlet end 222, a closed end 224, and a length between the two ends. On the front side 226 of housing 230 (facing left as shown), an opening 232 extends along a length L and a width w between the inlet end 222 and the closed end 224 and directionally from a portion of the periphery of housing 230 (see FIG. 2B). A porous diffuser membrane (not shown) is retained within the opening.

[0024] Gaseous fluid enters the diffuser 200 at the inlet end 222 and flows along the length of the diffuser 200 in the direction of the arrows in FIG. 2A. As the fluid passes along the length, a portion of the fluid passes laterally (see arrows in FIG. 2A) through a porous diffuser membrane that extends along the front surface 226. The fluid passes through the porous diffuser membrane and enters the interior 220 of the sealed chamber 202.

[0025] 2B shows a top cutaway view of diffuser 200 and chamber 202. Details shown in FIG. 2B include front and back walls 212, 214 of chamber 202, side walls 242, 244, and back wall 246 of diffuser housing 230, and an internal channel 240 within diffuser housing 230. Internal channel 240 is defined by a porous diffuser membrane (not shown) located on front surface 226 and by three elongated, non-porous side walls on three other sides, including left and right side walls 242, 244, and back wall 246. Each side wall 242, 244, and 246 is non-porous, i.e., impermeable to gas flow, and each side wall 242, 244, and 246 includes a non-porous inner surface that defines internal channel 240 extending along the length L of housing 230.

[0026] Chamber 202 may be a component of a device or apparatus used in manufacturing, storing, transporting, or handling multiple semiconductor wafers. For example, exemplary types of devices containing chamber 202, shown in Figures 2A and 2B, include devices and apparatus commonly known as wafer carriers ("FOUPs") and wafer transfer stations. Other examples include deposition chambers (e.g., chemical vapor deposition chambers, atomic layer deposition chambers, etc.), and etch chambers, among others. Exemplary gases that may be dispensed for any of these processes include inert gases, reactive or corrosive gases (e.g., halogens or halogen-containing gases such as hydrogen bromide), and others.

[0027] 2A, diffuser 200 can be used to deliver a gas, such as an inert gas, from an external source to interior 220 of chamber 202. According to an exemplary diffuser housing and diffuser assembly, the diffuser housing includes the described channels defined within the interior of the housing by non-porous sidewalls (the term "sidewalls" refers to the sidewalls and backwalls), the channels designed with size and shape features that control the flow of gaseous fluid through the diffuser membrane to create useful, desired, or improved flow characteristics, including along the diffuser length with a desired uniformity of flow (based on flow pressure, flow rate, or both) through the diffuser membrane.

[0028] The purpose of a directional diffuser is to distribute the gaseous fluid as a uniform flow of gas through the chamber. To that end, the described diffuser assemblies can be designed to include internal channels that include shapes or dimensions that vary along the length of the channel in a manner that provides added control of the flow of gas through the diffuser, for example, by improving the uniformity of the flow through the diffuser membrane at different locations along the length of the diffuser membrane. See, e.g., FIG. 5A.

[0029] To achieve improved uniformity of flow along the length of the diffuser, the internal channel may exhibit varying cross-sectional size (area, having a width component and a depth component, both perpendicular to the length of the diffuser housing, as shown in FIG. 1 ) or dimension (e.g., depth or width) along said length as one way of providing the desired control of flow through the diffuser. During use, when a gaseous fluid is placed under pressure in the internal channel and flows from the inlet end to the closed end of the diffuser assembly, the pressure of the fluid will vary along the length of the diffuser. The pressure of the gas within the channel will typically decrease at locations in the channel farther from the source of gas pressurization, i.e., farther from the inlet end and closer to the closed end.

[0030] To accommodate (e.g., reduce or prevent) a decrease in gas pressure along the length of the internal channel as gas flows from the inlet end to the closed end of the channel, the channel can be adjusted in size, i.e., in cross-sectional area, depth, width, or a combination thereof, along its length. To improve the uniformity of gas flow through the diffuser membrane, which means providing a more uniform flow of gas (based on flow rate or gas pressure) through the diffuser membrane as measured at different locations along the length of the diffuser membrane, the internal channel can have a cross-sectional area, depth, or both that decreases along the length of the channel, with the channel having a larger cross-sectional area, depth, or both nearer the inlet end and a reduced cross-sectional area, depth, or both nearer the closed end.

[0031] An example of a diffuser (300) including an internal channel having a depth and cross-sectional area that varies along the length of the internal channel is shown in Figures 3A, 3B, and 3C. Figure 3A shows a side perspective view of the directional diffuser 300, Figure 3B shows a top view of the directional diffuser 300, and Figure 3C shows a side cutaway view of the directional diffuser 300. Referring to Figure 3A, the exemplary directional diffuser 300 is shown. The directional diffuser 300 includes a housing 312 having a length (L), a width (w), and a depth (d). The housing 312 includes an inlet 302 at an inlet end 306, a second end ("closed end") 304, and a length L extending between the inlet end 306 and the closed end 304. On the front side 308 of the housing 312, an opening 318 extends along the length L and width w between the inlet end 306 and the closed end 304. A porous diffuser membrane (not shown) may be held within opening 318 as part of the diffuser assembly.

[0032] Inlet 302 opens into an interior channel 310 defined by an opening 318 on one side and by three elongated (in the length direction) non-porous sidewalls on three other sides, including left and right sidewalls 314 and 316 and a bottom or back sidewall 322. The sidewalls are not separate but blend together as a single curved surface. Each of sidewalls 314, 316, and 322 is non-porous, i.e., impermeable to gas flow, and each sidewall 314, 316, and 322 includes a non-porous inner surface 324 that defines an interior channel extending along the length L of housing 300.

[0033] As best shown in FIG. 3C , interior channel 314 has a cross-sectional area and depth (d) that vary along the length (L) of channel 310. With particular regard to depth, near inlet end 306, a non-porous lower or back surface 324, which defines a portion of interior channel 310, meets channel 302a of inlet 302. Surface 324 defines the depth (d) of channel 310 between opening 318 and surfaces 324 of sidewalls 314, 316, and 322. Depth (d) is greatest at approximately midpoint 330 of channel 324, between distal end 334 of channel 310 and proximal end 332 of channel 310.

[0034] Another example of a diffuser (400) including internal channels each having a varying cross-sectional area and depth along the length of the internal channel is shown in Figure 4. Figure 4 shows a side cutaway view of the directional diffuser 400 including a diffuser housing 412 having a length (L), a width (w), and a depth (d). The housing 412 includes an inlet 402 at an inlet end 406, a second end ("closed end") 404, and a length L extending between the inlet end 406 and the closed end 404. On the front side 408 of the housing 412, an opening 418 extends along the length L and width w between the inlet end 406 and the closed end 404. A porous diffuser membrane (not shown) may be retained within each elongated opening 418 as part of the diffuser assembly.

[0035] The inlet 402 opens into an interior channel 414 defined by an opening 418 on one side and an elongated (lengthwise) non-porous sidewall on the remaining side. As shown, the interior channel 414 has a depth (d) that varies along the length (L) of the channel 414 between the inlet end 406 and the closed end 404; the steady and gradual reduction in depth of the interior channel 414 in the distal portion of the housing 412 is sometimes referred to as a "tapered" depth, or a "tapered" or "gradual" reduction in depth. In particular, near the inlet end 406, the surface 324 defines the depth (d) of the channel 414 between the opening 418 and the back surface 424. The depth (d) is greatest at d and gradually decreases along the length L in a direction toward the closed end 404.

[0036] According to certain exemplary diffusers herein, the diffuser may be designed with internal channels that control the flow of fluid through the length of the diffuser housing and through the diffuser membrane at different locations along the length of the housing to create improved uniformity or uniformity of flow through the diffuser membrane at locations along the length of the diffuser. Generally, in directional diffusers that include internal channels that are uniform in cross section and dimension along the length of the diffuser, the flow of gas through the diffuser membrane (at locations along the length of the diffuser) is not uniform by having a higher flow (or pressure) of fluid at the inlet end and a lower flow (or pressure) at the outlet end.

[0037] 5A and 5B diagrammatically show the gas flow rate (velocity) of a gaseous fluid flowing through the membranes 510 and 610 of the illustrated diffusers 500 and 600. Referring to FIG. 5A, the diffuser 500, including the membrane 510, has an internal channel (not shown) that is uniform in cross-sectional area and dimensions along the length of the diffuser 500, from the inlet end 512 to the closed end 514. The gaseous fluid flows into the inlet end 512 and passes along the length of the diffuser 500 toward the closed end 514. Along this path, the pressure of the fluid within the internal channel gradually decreases, which causes a gradually reduced level of flow through the membrane 510.

[0038] 5A and 5B show higher and lower rates of fluid flow through diffuser membrane 510 and membrane 610 as ranges of gray shades. The different relative flow rates are shown in gray scale. The flow in FIGS. 5A and 5B is lowest at the outer peripheral edges (518, 618) of diffuser membrane 510. Slightly higher relative flow rates occur at locations 524 and 624 and areas of the same gray shade. Even slightly higher relative flow rates occur at locations 522 and 622 and areas of the same gray shade. The highest relative flow rates are in the darkest areas, locations 520 and 620 and areas of the same dark gray shade.

[0039] 5A shows that the fluid flow through the diffuser membrane 510 is greatest in region 502 near the inlet end 512 and gradually reduces along the length of the diffuser 500 toward the closed end 514, with the lowest flow rate near the closed end 514. While the lack of uniformity in the flow rate through the membrane 510 may not precisely correlate to the distance from the inlet, in a general sense, the fluid pressure in the interior channels and the fluid flow rate through the membrane 510 are greatest near the inlet end 512 and lowest near the closed end 514 of the diffuser 500.

[0040] In contrast, Figure 5B shows the reduced variability in fluid flow rate through the diffuser membrane along the length of the diffuser for the illustrated diffuser. Referring to Figure 5B, diffuser 600, including membrane 610, has internal channels (not shown) that exhibit a gradually reduced depth and cross-sectional area along the length of the diffuser, with a greater depth and cross-sectional area near inlet end 610 and a lower (e.g., smallest) depth and cross-sectional area near closed end 614. Gaseous fluid flows into inlet end 612 and passes along the length of diffuser 600 toward closed end 614. Along this path, the cross-sectional area and depth of the internal channels of diffuser 600 are gradually reduced.

[0041] 5B shows fluid flow through diffuser membrane 610 being more uniform along the length of diffuser 600 compared to the fluid flow through diffuser membrane 510 of diffuser 500, which does not have a variable depth or cross-sectional area along the length of diffuser 500. The improved uniformity of the flow rate through membrane 610 can be observed as a relatively uniform flow rate of fluid through membrane 610 in region 602 near inlet end 612 compared to the flow rate of fluid through membrane 610 in region 604 near closed end 614. While the flow rate of gas through membrane 610 may not precisely correlate to distance from inlet end 612, in a general sense, the flow rate of gaseous fluid through membrane 610 is not significantly different in region 602 compared to the flow rate of fluid through membrane 610 in region 604. While some amount of variability in the flow rate of the gaseous fluid still remains along the length of the diffuser 600 and membrane 610, that variability is reduced relative to the diffuser of FIG. 5A and does not include a significant or clear maximum flow near the inlet end 612 or a significant or clear minimum level of pressure or flow near the closed end 614.

[0042] A diffuser assembly can include the described diffuser housing and one or more diffuser membranes attached to and contained within one or more openings extending along the length of the housing on one side of the housing. In use, when gas passes from the internal channel to the exterior of the directional diffuser, the gas must pass through the diffuser membrane. The diffuser membrane is positioned with one surface facing the internal channel of the housing and a second surface facing the space exterior to the housing, which in use is the enclosed interior space of the chamber.

[0043] A variety of different types of diffuser membranes are known, including various porous or apertured sheet-like structures ("membranes") that allow the flow of gaseous fluids through the structure. Membrane diffusers are effective in distributing a uniform flow of reagent gas from a gas source, through an internal channel of a housing, through the diffuser membrane, and into the interior space of a chamber, with the diffuser assembly extending into the interior space of the chamber. The diffuser membrane is designed to cause the reagent gas to flow uniformly throughout the reaction chamber, distributing the gas uniformly within the chamber in a diffused manner, to prevent the flow from disturbing and displacing particulate contaminants that may be present in the interior space.

[0044] An example of a diffuser membrane formed from a sintered porous body is described in U.S. Patent Application Publication No. 2013 / 0305673, which is incorporated herein by reference in its entirety.

[0045] According to a preferred example of the diffuser assembly, the described directional diffuser includes a flat or slightly curved sheet-type diffuser membrane capable of producing a flow of water through the diffuser assembly that exits the diffuser membrane in a substantially laminar flow that is relatively uniform along the length of the diffuser membrane and falls from the diffuser membrane as a film or curtain. Figure 6 is a photograph of an example of a directional diffuser of this preferred type exhibiting laminar flow of water through the diffuser under test conditions.

[0046] The diffuser assemblies herein can be tested for this type of desired laminar flow characteristic using water by allowing water (e.g., deionized water) to flow through the assembly by entering the inlet, flowing through the internal channels, and then flowing through a diffuser membrane located on one surface of the diffuser assembly. With the diffuser assembly oriented horizontally, with its length and width in a common horizontal plane, and with the diffuser membrane pointing downward and its depth oriented vertically, water at low to moderate pressures is made to flow into the inlet and allowed to pass through the diffuser membrane. Desirably, when tested at ambient pressure and temperature, the water will flow relatively uniformly through the diffuser membrane, preferably in the form of a thin film or "curtain" formed from the flowing water along the length of the diffuser membrane. The water flowing from the membrane preferably retains the film or curtain form as long as the flow is maintained. See Figure 6.

[0047] The diffuser housings described herein, having the described elongated configuration, input end, closed end, and interior channel, are not limited with respect to the particular method used to prepare the housings. The described housings can be prepared by any current or future manufacturing method that would be effective to form the described diffuser housings.

[0048] Several specific methods may be useful for forming different examples of the described diffuser housings. For example, diffuser housings that include internal channels with variable cross-sectional area and / or depth along the length of the channels may be difficult to form on a commercial scale in a cost-effective manner by using only machining, molding, or CNC (computer numerical control) equipment and techniques.

[0049] In accordance with exemplary methods and exemplary diffuser housings, techniques that have been found to be effective for preparing diffuser housings or components of diffuser housings include additive manufacturing techniques, including those commonly referred to as "3D printing" techniques.

[0050] Many different versions of additive manufacturing techniques are known. Additive manufacturing methods generally involve a series of individual layer-forming steps, sequentially forming layers upon layers of solidified feedstock composite obtained from a feedstock composite. Some specific examples of general types of additive manufacturing techniques include what are commonly referred to as "powder bed" additive manufacturing methods, including various "binder jet printing" techniques. Other examples include stereolithography (SLS) and "feedstock distribution methods" (FDM). Yet another example, referred to as "laser metal deposition," or "direct metal deposition," or "direct energy deposition," involves the use of a laser and a feedstock composite (as a powder or wire) to sequentially form "weld pools" on a surface, which sequentially solidify to form multiple layers of a multilayer body.

[0051] The described diffuser bodies may be prepared by any of these additive manufacturing methods, as well as other methods, any of which are now known or may be developed in the future.

[0052] Using a series of additive manufacturing steps, each step forming a single layer of the structure, multiple layers of solidified feedstock are sequentially formed into a structure referred to herein as a multi-layer composite (or "composite"). As used herein, the term "composite" (or "multi-layer composite") refers to a structure formed by additive manufacturing by sequentially forming a series of multiple individual and individually formed layers of solidified feedstock. The composite takes the form of a diffuser housing, or a component of a diffuser housing, herein, which includes an inlet end with an inlet, a closed end, a length between the inlet end and the closed end, an opening on a front side, and an interior channel extending between the inlet and the closed end, the channel being defined along the length by the opening on the front side, an elongated, non-porous back surface, and elongated, non-porous side surfaces. The housing has dimensions referred to herein as length, width, and depth. In some embodiments, the cross-sectional area, depth, or both of the channel vary along the length of the channel.

[0053] According to an exemplary diffuser body prepared by additive manufacturing techniques, the entire housing, between the two ends and from the front to the back, can be formed and held together solely as a structure of multiple layers formed by the multiple layer forming steps of additive manufacturing methods and without joining two separately produced pieces together using a joining step such as a vacuum brazing step. A diffuser housing formed as a multi-layer composite by additive manufacturing methods, without joining (such as by vacuum brazing), is sometimes referred to herein as a "continuous" diffuser housing.

[0054] The term "continuous" in this context means that the complete housing is formed as a single-piece composite structure from multiple sequentially formed layers. The term "continuous" does not refer to a structure prepared by separately forming two individual pieces and then joining the two separately formed pieces together, for example, by vacuum brazing techniques or by a different type of joining technique. A continuous diffuser housing would not include seams or boundaries resulting from the joining step, particularly seams or boundaries made from a joining material or filler material having a different composition than the material of the diffuser housing.

[0055] One particular example of an additive manufacturing technique is a technique commonly referred to as "selective laser melting." Selective laser melting (SLM), also known as direct metal laser melting (DMLM) or laser powder bed fusion (LPBF), is a three-dimensional printing method that uses a high-power density laser to melt solid particles of a feedstock material, allowing the molten (liquid) material of the particles to flow and form a layer of molten material, which then cools and solidifies to form a solidified feedstock. According to some particular exemplary methods, the particles of the feedstock can be completely melted to form a liquid (i.e., liquefied), and the liquid material can be allowed to flow and form a substantially continuous, substantially non-porous (e.g., less than 80, 85, 90, or 95 percent porous) film, which then cools and hardens as a solidified feedstock layer of a multilayer composite.

[0056] Additive manufacturing techniques can be useful for forming diffuser housings made from a wide range of materials, including metallic materials (including alloys), metal matrix composite materials, ceramic materials, polymers, and combinations thereof.

[0057] With additive manufacturing techniques, including selective laser melting techniques, the range of possible metals, alloys, and metal matrix composites that can be used to form the diffuser housing can advantageously include materials that are not easily formed into useful diffuser housings by previous techniques, such as machining techniques. The range of materials available with additive manufacturing techniques includes metals and metal alloys that can be melted by laser energy, such as aluminum alloys, iron-based alloys (stainless steel alloys), titanium alloys, nickel and nickel-based alloys, and various metal matrix composites, some of which are not easily processed by machining. Exemplary materials can exhibit such high hardness that they can be difficult to process by machining techniques to form the precise structure of the diffuser housing, including precise and varying dimensions (e.g., varying depths). Using additive manufacturing techniques, these materials can be processed to form diffuser housings including interior channels with variable dimensions along the length of the channels, e.g., variable cross-sectional areas, variable depths, or both, even from materials that would similarly be difficult to form using standard machining techniques.

[0058] The material used to prepare the diffuser housing can be any material that is useful for preparing diffuser housings, such as inorganic materials, including various metals (including alloys), metal matrix composites, ceramic materials, and polymers.

[0059] Examples of useful polymers may include polyethylene, polystyrene, and fluoropolymers, including hydrofluoropolymers and perfluoropolymers such as polytetrafluoroethylene (PTFE) and perfluoroalkyl polymers (PFA).

[0060] The term "metal" is used herein in a manner consistent with the meaning of the term "metal" within metallurgical, chemical, and additive manufacturing technologies, and refers to any metallic or semi-metallic chemical element, or an alloy of two or more of these elements.

[0061] The term "metal matrix composite" ("MMC") refers to a composite material prepared to contain at least two constituents or phases, one phase being a metal or metal alloy, and another phase being a different metal or another non-metallic material, such as fibers, particles, or whiskers, dispersed in the metal matrix. The non-metallic material can be carbon-based, inorganic, ceramic, etc. Some exemplary metal matrix composites are made from combinations of aluminum alloys with alumina particles, aluminum alloys with carbon, aluminum alloys with silicon, aluminum alloys with silicon carbide (SiC), titanium alloys with TiB2, titanium alloys with silicon, and titanium alloys with silicon carbide (SiC).

[0062] Metals and metal alloys that may be useful according to the methods herein include metals and metal alloys that have been used in the past to prepare diffuser structures, as well as other materials that have not been used. Useful or preferred materials include metals and various metal matrix composites, such as iron alloys (e.g., stainless steel and other types of steel), titanium and titanium alloys, nickel and nickel alloys (e.g., Hastelloy C22, Hastelloy C276), aluminum and aluminum alloys, molybdenum and molybdenum alloys, etc.

[0063] Additive manufacturing methods allow a complete (or substantially complete) functional diffuser housing to be prepared using a single manufacturing process (a single additive manufacturing “step”), which provides high manufacturing efficiency (high manufacturing throughput) in a reduced amount of time per unit. A diffuser housing substantially complete with all required structures (e.g., inlet end, closed end, front face, side walls, and interior channels) can be prepared by a single series of additive manufacturing steps. For example, what is sometimes referred to as a “one-step” additive manufacturing process for forming a diffuser structure can form many, most, or all of the required structures (e.g., inlet end, closed end, front face, side walls, and interior channels) of a diffuser housing as a single, multilayer composite as described. A one-step additive manufacturing process avoids the need for individually forming multiple separate pieces by separate steps, followed by an additional step of joining the multiple, separately formed pieces together to form the functional diffuser structure.

[0064] Furthermore, additive manufacturing techniques can be used to form diffuser housings having highly accurate dimensions or varying dimensions or shapes, including shapes or varying dimensions that are difficult to form by conventional techniques, including varying dimensions (cross-sectional area, depth, width, or a combination thereof) of the internal channel along the length of the internal channel.

[0065] Each layer of the composite can be formed as desired, from the desired material, and to the desired thickness, to create a diffuser housing in the form of a multilayer composite having the described design. By an exemplary additive manufacturing method, each layer is prepared from a collection of particles (called a "feedstock"), generally in powder form. The feedstock contains small particles made from one or a variety of different inorganic materials that can be melted by a high-energy laser to liquefy, flow, form layers of molten material, and then cool and solidify to form the layers of the multilayer composite.

[0066] Useful particles according to the present disclosure can be any particles that can be processed to form the described useful multilayer composites. Examples of useful particles include inorganic particles that can be fully melted, partially melted (e.g., sintered), or liquefied by laser energy to form the described layers of the diffuser housing. Examples of such particles include inorganic particles made from metals (including alloys), ceramics, or metal matrix composites. Some useful examples generally include metals and metal alloys, and metal matrix composites, such as stainless steel, nickel-based alloys, aluminum and aluminum alloys, and titanium and titanium alloys.

[0067] Useful particles of the feedstock can be of any size (e.g., average particle size) or size range that is effective, including small or relatively small particles on the micron scale (e.g., having an average size of less than 500 microns, less than 100 microns, less than 50 microns, 10 microns, or less than 5 microns).

[0068] The particles may be selected to achieve effectiveness in the described processes, such that they can be contained in the feedstock, formed into a feedstock layer, and fully melted or partially melted (e.g., sintered) to form a layer containing the molten particles, which can be cooled to form the solidified feedstock as a layer of a multilayer composite. The size, shape, and chemical composition of the particles may be any that is effective for these purposes.

[0069] The particles can be in the form of a feedstock composite that can be used in the additive manufacturing processes herein. By way of example, a feedstock useful in an additive manufacturing process can include particles that can be heated, partially melted or fully melted, and then cooled to form layers of a multi-layer composite. The feedstock material is not required to include other materials, but can optionally include amounts of other materials if desired.

[0070] Exemplary feedstock composites for use in selective laser melting or selective laser sintering techniques may contain at least 80, 90, or 95, 98, or 99 percent inorganic particles by weight, based on the total weight of the feedstock composite. If desired, other ingredients may be present in minor amounts, such as one or more of a flow aid, surfactant, lubricant, leveling agent, etc.

[0071] Each layer of the multilayer composite can be formed to have any useful thickness. The thickness of a layer of the multilayer composite is measured from the layer of the composite after the layer is formed by melting particles of the feed layer to form a molten feed layer and then cooling to form a solidified feed layer of the composite. Exemplary thicknesses of the solidified layer of the composite can range from 30 microns to 100, 200, or more microns, e.g., from 30 to 50, 60, 70, 80 microns, up to 90, 100, 150, 200, 300, 400, or 500 microns. In exemplary composite structures, all layers of the composite can have the same or substantially the same thickness. In other exemplary composite structures, the layers do not all have the same thickness, but different layers of the composite can each have different thicknesses.

[0072] The described diffuser housing can be prepared by additive manufacturing methods that use a series of individual layer-forming steps to form a high-density metal or metal matrix composite multilayer composite structure. As one example, a technique called laser additive manufacturing (LAMT) can be used to form the multilayer composite layer-by-layer, in an "additive manufacturing" manner. Laser additive manufacturing uses high-power laser energy to selectively cause metal or metal matrix composite particles in a feedstock layer to heat, melt (at least partially), and flow, forming a substantially solidified feedstock layer. By one specific example, called selective laser melting (SLM), the feedstock layer is melted to form a substantially continuous, non-porous fused layer, which solidifies as a substantially continuous, non-porous solidified feedstock layer. By another specific example, called selective laser sintering (SLS), the feedstock layer is sintered (partially melted) to form a layer of partially melted feedstock particles, which, upon cooling, forms a solidified feedstock layer that may contain a level of space between the melted particles as pore space.

[0073] More specifically, multilayer composites can be built by sequential steps that create many thin cross sections (herein, "solidified feedstock" of "layers") of a larger three-dimensional structure (the composite). A layer of feedstock is formed and includes many particles of a metal or metal matrix composite. Laser energy is selectively applied to the feedstock layer over a portion of the feedstock layer. The portion of the feedstock layer that receives the laser energy is the portion that will be formed as the diffuser housing.

[0074] The laser energy at least partially melts particles in the portion of the feedstock exposed to the laser energy, the molten material of the particles liquefying and flowing to contact other molten particles, and the molten particles cool and solidify as a layer of solidified feedstock.

[0075] After the initial layer of solidified feedstock is formed, an additional thin layer of feedstock is deposited on top of the completed layer containing the solidified feedstock. The process is repeated to form multiple layers of solidified feedstock, each layer formed on top of and attached to the top surface of the previous layer. Multiple layers are deposited, one on top of each completed layer, in order to form a multi-layer composite, which is a composite of multiple layers of successively formed solidified feedstock. The multiple layers can be of the same composite and thickness, or different composites and different layer thicknesses.

[0076] Binder jet additive manufacturing processes involve the addition of a polymer to form a solidified feedstock layer, the formation of a "green body" containing the polymer, and post-processing steps such as debinding and thermal treatment (e.g., sintering) to remove the polymer. Many laser-based additive manufacturing processes, such as those generally and in detail described herein, avoid the need for a polymer during the formation of the solidified feedstock layer. These laser-based processes also do not require a debinding or sintering step to form the final multilayer composite.

[0077] A first aspect is directed to a directional gas diffuser comprising an elongated housing, the housing having an inlet end, a closed end, a length between the inlet end and the closed end, an opening on a front side of the housing extending along said length, and a channel extending between the inlet end and the closed end, the channel being defined along said length by the opening extending along the front side, an elongated back side, and an elongated side, the channel having a length, width, depth, and a varying cross-sectional area along the channel length.

[0078] In a second aspect according to the first aspect, the length is greater than the width, and the width is greater than the maximum depth of the channel.

[0079] In a third aspect according to the first or second aspect, the depth decreases along a portion of the length as the channel extends towards the closed end.

[0080] In a fourth aspect according to any one of the first to third aspects, the back elongate surface is non-porous and the two side elongate surfaces are non-porous.

[0081] In a fifth aspect according to any one of the first to fourth aspects, the housing further comprises a multi-layer composite extending from the elongated rear side to the front side.

[0082] In a sixth aspect according to any one of the first to fifth aspects, the multilayer composite comprises a metal or metal alloy, a metal composite matrix, a ceramic, or a polymer.

[0083] In a seventh aspect according to any one of the first to sixth aspects, the multilayer composite does not include a seam.

[0084] In an eighth aspect according to any one of the first to seventh aspects, the diffuser further comprises a diffuser membrane secured to the opening.

[0085] In a ninth aspect according to the eighth aspect, relative to an otherwise equivalent diffuser having channels with uniform cross-sectional area, the varying cross-sectional area along the length creates a more uniform flow rate of fluid through the diffuser membrane along the length of the diffuser membrane.

[0086] In a tenth aspect according to the eighth or ninth aspects, the diffuser is capable of creating a laminar flow of water through the diffuser membrane, whereby the diffuser is positioned horizontally with the diffuser membrane facing downwards and water passing through the diffuser is capable of creating a continuous thin water film formed from the flowing water along the length of the diffuser membrane.

[0087] An eleventh aspect is directed to a directional gas diffuser comprising an elongated housing, the housing having an inlet end with an inlet, a closed end, a length between the inlet end and the closed end, an opening on a front side of the housing extending along the length, and an interior channel extending between the inlet and the closed end, the channel being defined along the length by the opening on the front side, an elongated, non-porous back side, and an elongated, non-porous side surface.

[0088] In a twelfth aspect according to the eleventh aspect, the length is greater than the width, and the width is greater than the maximum depth of the channel.

[0089] In a thirteenth aspect according to the eleventh or twelfth aspects, the depth decreases along a portion of the length as the channel extends towards the closed end.

[0090] In a fourteenth aspect according to any one of the eleventh to thirteenth aspects, the back elongate surface is non-porous and the two side elongate surfaces are non-porous.

[0091] In a fifteenth aspect according to any one of the eleventh to fourteenth aspects, the housing further comprises a multi-layer composite extending from the elongated rear side to the front side.

[0092] In a sixteenth aspect according to the fifteenth aspect, the multilayer composite comprises a metal or metal alloy, a metal composite matrix, a ceramic, or a polymer.

[0093] In a seventeenth aspect according to any one of the eleventh to sixteenth aspects, the multilayer composite does not include a seam.

[0094] An eighteenth aspect is directed to an apparatus comprising a chamber including an interior adapted to contain one or more semiconductor wafers, the chamber comprising the directional gas diffuser of any one of aspects 1 to 17 in the interior connected to a source of inert gas.

[0095] A nineteenth aspect according to the eighteenth aspect, selected from a wafer carrier and a wafer transfer station.

[0096] A twentieth aspect is directed to a method of equalizing pressure in a chamber of a wafer transfer station according to the nineteenth aspect, the method comprising distributing an inert gas through a diffuser to increase the pressure within the chamber, the chamber containing a plurality of semiconductor wafers, the chamber being closed and containing an interior that is below atmospheric pressure.

[0097] A twenty-first aspect is directed to a method of replacing a gaseous atmosphere in a chamber of a wafer carrier according to the nineteenth aspect, the method comprising distributing an inert gas through a diffuser to add the inert gas to the chamber while the chamber contains a plurality of semiconductor wafers in the gaseous atmosphere.

[0098] In a twenty-second aspect according to the twenty-first aspect, the gaseous atmosphere in the chamber is air, and the inert gas displaces the air.

[0099] A twenty-third aspect is directed to a method of making a housing of the directional gas diffuser of any one of the first to seventeenth aspects by additive manufacturing, the method comprising forming a first layer of solidified feedstock and forming a second layer of solidified feedstock on a surface of the first layer of solidified feedstock, wherein the layer of solidified feedstock is part of the housing.

[0100] A 24th embodiment according to the 23rd embodiment, further including forming a first feedstock layer on a surface, the first feedstock layer comprising inorganic particles; forming a solidified feedstock from the first feedstock layer; forming a second feedstock layer on the first feedstock layer, the second feedstock layer comprising inorganic particles; and forming a second solidified feedstock from the second feedstock layer, wherein the solidified feedstock layer is part of a housing of a directional gas diffuser.

[0101] A twenty-fifth embodiment according to the twenty-third embodiment, further comprising forming a solidified feedstock by melting the inorganic particles using a laser.

[0102] In a 26th aspect according to any one of the 23rd to 25th aspects, the solidified feedstock layer comprises particles selected from metal or metal alloy particles, metal composite matrix particles, ceramic particles, and polymer particles.

Claims

1. Elongated housing 1. A directional gas diffuser comprising: an inlet end; a closed end; an opening extending on a front surface of the housing; a channel having a smooth inner surface extending between the inlet end and the closed end; wherein the channel between the inlet end and the closed end comprises: the opening extending along the front surface; With a long, narrow back, With elongated sides and is longitudinally defined by a cross-sectional area of ​​the channel varies along the length of the directional gas diffuser; A directional gas diffuser, wherein the depth of the channel is greatest at a midpoint of the channel between the inlet end and the closed end.

2. A diffuser as described in claim 1, wherein the length of the channel is greater than the width of the channel, and the width of the channel is greater than the maximum depth of the channel.

3. A diffuser as described in claim 1, wherein the elongated back surface is non-porous and the two elongated side surfaces are non-porous.

4. A diffuser as described in claim 1, wherein the housing further comprises a multilayer composite extending from the elongated back surface to the front surface.

5. The diffuser of claim 4, wherein the multilayer composite comprises a metal or metal alloy, a metal composite matrix, a ceramic, or a polymer.

6. A diffuser as described in claim 4, wherein the multilayer composite does not contain seams.

7. A diffuser as described in claim 1, further comprising a diffuser membrane fixed to the opening.

8. A diffuser as described in claim 7, wherein a diffuser having channels with a cross-sectional area that varies along the length of the channel produces a more uniform flow rate of fluid through the diffuser membrane along the length of the diffuser membrane than a diffuser having channels with a uniform cross-sectional area along the length of the channel.

9. A diffuser as described in claim 7, wherein the diffuser is capable of creating a laminar flow of water through the diffuser membrane, whereby the diffuser is positioned horizontally with the diffuser membrane facing downwards and water passing through the diffuser is capable of creating a continuous thin water film formed from the flowing water along the length of the diffuser membrane.

10. Elongated housing 1. A directional gas diffuser comprising: an inlet end having an inlet; a closed end; an opening extending along a front surface of the housing; an interior channel having a smooth interior surface extending between the inlet and the closed end; and wherein the interior channel between the inlet and the closed end comprises: the opening on the front surface; A narrow, non-porous backing; With long, narrow non-porous sides and is longitudinally defined by A directional gas diffuser, wherein the depth of the internal channel is greatest at a midpoint of the internal channel between the inlet end and the closed end.

11. A diffuser as described in claim 10, wherein the length of the internal channel is greater than the width of the internal channel, and the width of the internal channel is greater than the maximum depth of the internal channel.

12. A diffuser as described in claim 10, wherein the elongated back surface is non-porous and the two elongated side surfaces are non-porous.

13. A diffuser as described in claim 10, wherein the housing further comprises a multi-layer composite extending from the elongated back surface to the front surface.

14. The diffuser of claim 13, wherein the multilayer composite comprises a metal or metal alloy, a metal composite matrix, a ceramic, or a polymer.

15. The diffuser of claim 13, wherein the multilayer composite does not include seams.

16. 10. An apparatus comprising a chamber including an interior adapted to contain one or more semiconductor wafers, the chamber comprising the directional gas diffuser of claim 1 in the interior connected to a source of inert gas.

17. 17. The apparatus of claim 16, selected from a wafer carrier and a wafer transfer station.

18. 20. A method of controlling pressure in a chamber of the wafer transfer station in the apparatus of claim 17, the method comprising distributing an inert gas through the diffuser to increase pressure within the interior while the chamber contains a plurality of semiconductor wafers and while the chamber is closed and contains the interior at less than atmospheric pressure.

19. 20. A method of replacing a gaseous atmosphere in a chamber of the wafer carrier in the apparatus of claim 17, the method comprising dispensing an inert gas through the diffuser to add inert gas to the interior of the chamber while the chamber contains a plurality of the semiconductor wafers in the gaseous atmosphere.

20. The method of claim 19, wherein the gaseous atmosphere in the chamber is air and the inert gas displaces the air.

21. 10. A method of making a housing for a directional gas diffuser according to claim 1 by additive manufacturing, said method comprising: forming a first layer of solidified feedstock; forming a second layer of solidified feedstock on the surface of the first layer of solidified feedstock; Including, The method, wherein the first layer of solidified feedstock and the second layer of solidified feedstock are part of the housing.

22. forming a first feedstock layer on the surface, the feedstock layer comprising inorganic particles; forming a first solidified feedstock from the first feedstock layer; forming a second feedstock layer on the first feedstock layer, the second feedstock layer comprising inorganic particles; forming a second solidified feedstock from the second feedstock layer; Further comprising:

22. The method of claim 21, wherein the first layer of solidified feedstock and the second layer of solidified feedstock are part of a housing of the directional gas diffuser.

23. 22. The method of claim 21, further comprising forming the solidified feedstock by melting inorganic particles using a laser.

24. The method of claim 21, wherein the solidified feedstock comprises particles selected from metal or metal alloy particles, metal composite matrix particles, ceramic particles, and polymer particles.

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