Buffer holder for substrate container

Abstract

The invention relates to a buffer holder for a substrate container. A substrate holder (110) is provided that exhibits a substantially uniform contact surface (128) that can accommodate a large change in position in which substrates on the substrate holder are aligned. The uniform contact surface (128) is allowed to deflect and compress in order to eliminate the possibility that a substrate (114) is damaged by the substrate holder (110) or is unintentionally clamped within the substrate holder (110) or is pressed too tight by the uniform contact surface (128). With this arrangement, no adhesive or tape is utilized, so there is no concomitant degassing of volatile organic compounds that contaminate the microenvironment or concurrent events due to incompatibility of such adhesives and tapes with the washing process.

Description

[0001] Information about divisional applications

[0002] This application is a divisional application of an invention patent application with an application date of February 3, 2017, application number 201780014884.8, and invention name “Buffer Retainer for Substrate Container”.

[0003] Related Applications Cross Reference

[0004] This application claims the benefit of U.S. Provisional Application No. 62 / 292,055, filed on February 5, 2016, and entitled “Cushion Retainer for Substrate Container,” which is hereby incorporated by reference in its entirety. Technical Field

[0005] The present invention generally relates to holding substrates in substrate containers, and more particularly to buffer holders for substrate containers. Background Art

[0006] A front opening unified transport box (FOUP) is a container for storing and transporting wafers and other disc-shaped substrates. Many conventional FOUPs utilize molded polymer holders that include multiple cantilever or bridge-like structures that flex to abut against the edge of the substrate to provide holding force and cushioning functions. The holder is located on the inside of the FOUP door so that the cantilever or bridge-like structure faces and contacts the edge of the substrate when the door is installed.

[0007] However, substrates are known to become stuck and clamped between the cantilever or bridge-like structures of conventional holders. The clamping of the substrate can damage the peripheral portion near the edge of the substrate and can cause the holder to fail to provide the desired cushioning function. In addition, the clamping of the substrate can cause the substrate to become ejected from the container immediately after the door is removed, which can cause damage not only to the clamped substrate but also to other substrates contained within the container. This unintended ejection of the substrate from the container can also cause general disruption and contamination risks to the manufacturing process.

[0008] Substrates are now being manufactured in larger and larger sizes. Additionally, there is a trend in the semiconductor industry toward implementing substrates with reduced thickness. As a result, some substrates have a tendency to warp due to the effects of the delamination process. Combined with the sag due to gravity, the randomness of the warp magnitude and direction can cause the alignment of the front edge of the substrate to exceed the allowable tolerance outside the holder, resulting in misalignment of the substrate with the cantilever or bridge-like structure of the holder.

[0009] Referring to FIG. 1 , a conventional substrate holder 30 is depicted engaging planar substrates 32 and non-planar substrates 34 within a front opening unified transport pod (FOUP) 36. The conventional substrate holder 30 is mounted to a door 38 of the FOUP 36 and includes a substrate engaging portion 42 suspended on a cantilever or bridge-like structure 44. The intended function of the substrate holder 30 is to flex against a front or leading edge 46 of the substrates 32, 34 to provide holding force and cushioning to the substrates 32, 34. According to the intended design, the planar substrate 32 is seated within the wafer engaging portion 42. However, the non-planar substrate 34 is depicted as being stuck between adjacent substrate engaging portions 42. In this scenario, the conventional substrate holder 30 may damage the non-planar substrate 34. Additionally, non-planar substrates 34 may become clamped between adjacent substrate engagement portions 42, such that when door 38 and conventional substrate holder 30 are removed from FOUP 36, non-planar wafers 34 are ejected from wafer carrier 48 of FOUP 36 in an unintended and unpredictable manner. Such ejection of non-planar wafers 34 may damage not only the non-planar wafers 34, but other wafers contained within FOUP 36, and may also result in general disruptions to the manufacturing process and risk of contamination. Misalignment may render the holder unable to provide the desired cushioning function for the substrate.

[0010] Other arrangements have been suggested. For example, in one arrangement, a holder having a solid compressible support unit mounted to the back side of a solid cover body has been proposed. However, this arrangement does limit the amount by which the compressible support unit can deflect and thus provides too much pressure to the planar substrate, thus potentially causing damage. As can be seen from the above discussion, there is a need in the art for a holder that remedies these problems. Several embodiments for addressing these problems are discussed below. Summary of the invention

[0011] The present invention relates generally to a substrate holder presenting a substantially uniform contact surface that can accommodate large variations in the position of alignment of the substrate thereon. The uniform contact surface eliminates the possibility of a substrate being damaged by the substrate holder or being inadvertently clamped within the substrate holder. In addition, the substrate holder has a holder cushion and a mounting structure configured to secure the holder cushion at the outer peripheral portion of the cushion and allow a central region of the cushion to deflect relative to the mounting structure. In operation, a substrate is placed in a substrate container and held by pressing the central region of the holder cushion against the substrate while allowing the central region to compress and deflect so as not to damage the substrate. In addition, no adhesives or tapes are utilized in the disclosed embodiments, and therefore there is no concomitant outgassing of volatile organic compounds that contaminate the microenvironment, or complications resulting from the incompatibility of such adhesives and tapes with a washing process.

[0012] In some embodiments, a temporary replacement substrate holder for supporting a consumable foam, rubber or elastomer insert is disclosed. The substrate holder of the present invention may be a molded plastic component that is attached to the inner side of the FOUP door using the same features as a standard molded holder. Standard plastic cushioning uses cantilever or bridge-like features to apply small loads to the edge of the substrate, but the disclosed substrate holder does not have these cantilever or bridge-like features for applying loads directly to the substrate. Alternatively, the mounting structure is designed to support the foam, rubber or elastomer insert for the purpose of cushioning the edge of the substrate. The mounting structure retains the consumable foam, rubber or elastomer cushion by using features that retain the peripheral portion of the insert or pin and socket connector with or without barbs without the use of adhesives or tapes. In some embodiments, the cushion is overmolded onto the mounting structure. In other embodiments, the peripheral portion of the cushion may be formed with full-length barbs retained by a slot or groove cut through the mounting structure. The disclosed mounting structure accommodates a simplified assembly and removes the foam, rubber or elastomer holder cushion for washing operations and for periodic replacement.

[0013] In some embodiments, the door is configured with the necessary mounting features (eg, hooks, posts, or slots) to directly attach the retainer cushion without the need for an intermediate mounting structure.

[0014] In one illustrative embodiment, a substrate holder for a substrate container includes a holder cushion including a body portion having a thickness defining a thickness dimension. The body portion includes a flexible material that is compressible in the thickness dimension. A mounting structure is configured to secure the holder cushion without the use of an adhesive. In some embodiments, the flexible material is one of a foam material, a rubber material, or an elastomeric material. The mounting structure may be configured to mount to a door of a substrate container, the substrate container being a FOUP.

[0015] In various embodiments, the mounting structure is configured to secure the retainer cushion by compression of an overall dimension of the body portion, the mounting structure applies a reaction force in response to compression of the overall dimension to retain the retainer cushion within the mounting structure, the mounting structure being configured to be mounted to the substrate container. In some embodiments, the mounting structure defines a recess in which the retainer cushion is disposed.

[0016] In some embodiments, the compressed overall dimension is a transverse dimension orthogonal to the thickness dimension. Compression of the transverse dimension may cause the body portion to bend to define a bend of the body portion in the direction of the thickness dimension. In some embodiments, the recess of the mounting structure is configured to accommodate the bend of the body portion. The mounting structure may further include at least one transverse protrusion defining a minimum transverse dimension of the recess. In some embodiments, the mounting structure includes a latch arm configured for coupling the mounting structure to a standard FOUP door.

[0017] In various embodiments of the invention, the mounting structure comprises a frame having side members separated by a plurality of cross members, each cross member defining a mounting surface, the retainer cushion being coupled to the mounting surface of each of the plurality of cross members. The cross members extend transversely relative to the side members. The side members and the plurality of cross members may be one-piece. Each of the plurality of cross members may be arcuate such that the mounting surface is concave or convex. In some embodiments, mounting features extend from the frame for coupling the mounting structure to a substrate container. Axial members may bridge adjacent ones of the plurality of cross members.

[0018] In various embodiments of the invention, the plurality of cross members include a plurality of protrusions, at least one of the plurality of protrusions being disposed on each of the plurality of cross members, the plurality of protrusions extending into or through the thickness of the body portion. The body portion of the retainer cushion may define a plurality of mounting holes, each positioned on the body portion for mating with a corresponding one of the plurality of protrusions and each sized for friction fit with the corresponding one of the plurality of protrusions. In some embodiments, the mounting holes pass through the thickness of the body portion.

[0019] In various embodiments of the present invention, a plurality of extensions extend from a face of the body portion in the direction of the thickness dimension, wherein the plurality of cross members define a plurality of apertures. At least one of the plurality of apertures is defined by each of the plurality of cross members, and each of the extensions is sized and positioned on the body portion to mate with the plurality of apertures. The plurality of extensions and the plurality of apertures may be sized for a friction fit therebetween to secure the retainer cushion to the mounting structure. In some embodiments, each of the plurality of extensions includes a neck portion and a bulbous portion distal to the neck portion, the neck portion being disposed in a corresponding one of the plurality of apertures, the bulbous portion being aligned to abut against a second face of the corresponding one of the plurality of cross members to secure the retainer cushion to the cross member, the second face being opposite the mounting face of the corresponding one of the plurality of cross members. The extension and the body portion may be one-piece.

[0020] The foregoing summary is provided to facilitate an understanding of some of the unique innovative features of the present invention and is not intended to be a complete description. A complete understanding of the present invention can be obtained by taking the entire specification, claims, drawings, and abstract as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention may be more fully understood from the following description of various illustrative embodiments considered in conjunction with the accompanying drawings, in which:

[0022] Figure 1 depicts the interaction of a substrate with a conventional holder.

[0023] Figure 2A is a side elevation cross-sectional view of a front opening unified transport box (FOUP) according to an embodiment of the present invention.

[0024] Figure 2B is a cross-sectional view of a retainer cushion engaged with a resident wafer in accordance with an embodiment of the present invention.

[0025] Figure 3 is a front view of a FOUP door with a substrate holder according to an embodiment of the present invention.

[0026] Figure 4 According to an embodiment of the present invention, in the assembly Figure 3 A perspective view of a substrate holder.

[0027] Figure 5 is a perspective view of a frame for supporting a retainer cushion according to an embodiment of the present invention.

[0028] Figure 6 is a device for installation according to an embodiment of the present invention Figure 5A partial perspective view of a retainer cushion of a frame.

[0029] Figure 7 is installed according to an embodiment of the present invention Figure 5 The framework Figure 6 A partial cross-sectional view of a retainer cushion.

[0030] Figure 8 is a partial cross-sectional view of a retainer cushion having an enclosed mounting hole coupled to a frame according to an embodiment of the present invention.

[0031] Fig. 9 is a partial cross-sectional view of a retainer cushion having a cylindrical extension mounted to a frame in accordance with an embodiment of the present invention.

[0032] Fig.10 is a partial cross-sectional view of a retainer cushion having a bulbous extension mounted to a frame in accordance with an embodiment of the present invention.

[0033] Fig.11 is a perspective view of a FOUP door having a receptacle mounting structure integral therewith according to an embodiment of the present invention.

[0034] Fig.12 is a perspective view of a FOUP door having a mounting structure integral therewith including a cross member having an extension thereon in accordance with an embodiment of the present invention.

[0035] Fig.13 is a perspective view of a FOUP door having a mounting structure integral therewith including a cross member having an aperture in accordance with an embodiment of the present invention.

[0036] Fig.14 is a front view of a FOUP door with a substrate holder according to an embodiment of the present invention.

[0037] Fig.15 According to an embodiment of the present invention Fig.14 A partial cross-sectional view of a wafer engaged with a substrate holder.

[0038] Fig.16 is a front view of a FOUP door with a substrate holder according to an embodiment of the present invention.

[0039] Fig.17 is a perspective view of a frame for supporting a retainer cushion according to an embodiment of the present invention.

[0040] Fig.18 is installed according to an embodiment of the present invention Fig.17 A partial cross-sectional view of a retainer cushion of a frame.

[0041] Fig.19 is a perspective view of a substrate holder according to an embodiment of the present invention.

[0042] Fig. 20 is a perspective view of a substrate holder according to an embodiment of the present invention.

[0043] Although the present invention is susceptible to various modifications and alternative forms, it has been shown by way of example in the drawings and its details will be described in detail. However, it should be understood that it is not intended to limit the aspects of the present invention to the specific illustrative embodiments described. On the contrary, it is intended to cover all modifications, equivalent forms and alternative forms that fall within the spirit and scope of the present invention. DETAILED DESCRIPTION

[0044] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and / or" unless the content clearly dictates otherwise.

[0045] The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The detailed description and the drawings, which are not necessarily drawn to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments depicted are intended to be exemplary only. Unless expressly stated to the contrary, selected features of any illustrative embodiment may be incorporated into additional embodiments.

[0046] refer to Figure 2A , a substrate container 100 is depicted in an embodiment of the present invention. The substrate container 100 includes a housing portion 102 defining an opening 103, and a door 104 configured to form a closure for the opening 103. A substrate holder 110 is mounted on an interior face 106 of the door 104 for contacting a front or forward edge 112 of a resident substrate 114 stored within the substrate container 100, the resident substrate 114 being substantially centered about a central axis 116. Figure 2A In the depiction of , the forward edges 112 are depicted as being unevenly spaced along an axial direction 118 parallel to the central axis 116 .

[0047] The substrate holder 110 includes a holder cushion 120 supported by a mounting structure 130. The holder cushion 120 includes a body portion 122 having a thickness 124 defining a thickness dimension. The body portion 122 is made of a flexible material that is compressible in the thickness dimension. In addition, the holder cushion 120 is mechanically retained at an outer peripheral portion 133 by the mounting structure 130, such that no adhesive or tape is required to secure the body portion 122 to the substrate container 100. In the depicted embodiment, the mounting structure 130 is configured to be mounted to the door 104.

[0048] refer to Figure 2B , an embodiment of the present invention depicts the interaction of the substrate 114 with the central region 134 of the retainer buffer 120. The grooves and recesses are formed by interaction with the edge 112 of the resident substrate 114. Thus, the foam, rubber or elastomeric material compresses and is used to define a custom fit recess 136 that provides retention of the forward edge 112 of the resident substrate in the axial direction 118. The recess 136 is easily formed because, in addition to being compressed, the central region 134 of the retainer buffer 120 is also allowed to deflect away from the substrate 114. Due to the resiliency of the retainer buffer, the recess disappears as soon as the substrate 114 is disengaged.

[0049] The flexible material of the main body portion 122 may be a foam material, a rubber material, or an elastic material. Non-limiting examples of flexible materials include polyurethane or polyethylene. Flexible materials may also include fluoroelastomers (FKM), silicone, ethylene propylene copolymers (EPDM), urethanes, nitrile rubber (NBR), and synthetic rubbers. Injection moldable thermoplastic elastomers may also be implemented for the flexible material, including thermoplastic polyolefin elastomers (TEO), thermoplastic polyurethanes, copolyester elastomers, and polyether copolyamide thermoplastic elastomers. In some embodiments, the flexible material, for example, is carbon-loaded to dissipate static electricity.

[0050] In various embodiments, the hardness of the flexible material may be in the range of 50 to 90 Shore A, inclusive. In some embodiments, the hardness is in the range of 50 to 60 Shore A, inclusive. In some embodiments, the hardness is in the range of 80 to 90 Shore A, inclusive. Herein, a range referred to as "inclusive" includes the endpoint values ​​of the stated range and all values ​​between the endpoints.

[0051] Functionally, the holder buffer 120 of the substrate holder 110 presents a substantially uniform contact surface 128 that can accommodate large variations in the axial spacing between the leading edges 112 of the residing substrates 114. The uniform contact surface 128 eliminates the possibility of the residing substrates 114 being damaged by the substrate holder 110 or being inadvertently clamped within the substrate holder 110. Furthermore, since no adhesive or tape is implemented in the installation of the holder buffer 120, there is no concomitant outgassing of volatile organic compounds (VOCs) that contaminate the microenvironment. The holder buffer 120 can also be easily removed during washing of the substrate container 100.

[0052] Figure 2A The depicted embodiment of presents a FOUP type container. It should be noted that the embodiments and concepts depicted herein may be applicable to any substrate container that involves edge contact with one or more substrates for substrate holding and buffering, including but not limited to front opening shipping boxes (FOSBs) and standard mechanical interface (SMIF) pods. Also, Figure 2A The substrate container of FIG. 1 depicts the substrate holder 110 as being mounted to the door 104. Embodiments in which the substrate holder 110 is implemented at other locations within the substrate container (eg, mounted to the rear wall 132) are also contemplated.

[0053] As used herein, a "substrate" is a structure that is substantially planar or intended to be substantially planar and has a substantially uniform thickness and when properly supported. Substrate forms include sheets, plates, or flat plates. Substrates may have any shape, including circular, rectangular, and polygonal. Substrates may have homogenous materials, such as glass, silicon, or glass epoxy. Substrates may also include material compositions, such as doped materials (e.g., glass epoxy doped with copper or carbon), laminated composite materials (e.g., copper-clad epoxy), or core materials with coatings deposited thereon. Substrates also include masks used in lithography applications and silicon wafers that have been processed or partially processed by lithography techniques.

[0054] Herein, the substrate holder 110 is generally or collectively referred to by the reference number 110 and individually by the reference number 110 followed by a letter suffix (e.g., 110a). Similarly, the holder buffer 120 and the mounting structure 130 are generally or collectively referred to by the reference numbers 120 and 130, respectively, and individually by the reference numbers 120 and 130, respectively, followed by a letter suffix (e.g., 120a and 130a).

[0055] refer to Figure 3 and 4, an embodiment of the present invention depicts a substrate holder 110a including a mounting structure 130a and a holder buffer 120a. Generally, the mounting structure 130a is configured to secure the holder buffer 120a at portion 133a by compression of the overall dimensions of the body portion 122, and the mounting structure 130a applies a reaction force (e.g., friction or in response to bending) in response to the compression of the overall dimensions to retain the holder buffer 120a within the mounting structure 130a. As used herein, "overall dimensions" refers to the total or largest dimension along a given direction. For example, for a block-shaped body, the overall dimensions would be height, width, and thickness.

[0056] In some embodiments, the mounting structure 130a includes a receptacle 140 having a ridge portion 142 extending from a base portion 144, the ridge portion 142 and the base portion 144 cooperating to define a recess 146. The ridge portion 142 defines a lateral inner dimension 152 and an axial inner dimension 154. Herein, "lateral" refers to a direction parallel to the x-axis of a Cartesian coordinate 156 and "axial" refers to a direction parallel to the y-axis of the Cartesian coordinate, such as Figure 3 and 4 The base portion 144 may be substantially planar, or alternatively curved to define a convex or concave boundary of the recess 146. In some embodiments, at least one lateral protrusion 162 protrudes from an inner edge 164 of the ridge portion 142, thereby defining a minimum lateral dimension 158 of the recess 146.

[0057] In the depicted embodiment, the mounting structure 130a is configured to accommodate a retainer cushion 120a including a block-shaped body 180 having a peripheral portion 133a and a central region 134a. The block-shaped body 180 defines a height or axial dimension 182, a width or transverse dimension 184, and a thickness or thickness dimension 124 (i.e., a dimension parallel to the z-axis of the Cartesian coordinates). In some embodiments, the transverse dimension 184 of the block-shaped body 180 is greater than the transverse inner dimension 152 of the recess 146, and / or the minimum transverse dimension 158 of the recess 146.

[0058] The mounting structure 130a can be configured to mount to a substrate container 100, for example, to a door 104 of a substrate container 100. In some embodiments, a plurality of arms 192 extend from a spine portion of the receptacle 140. In various embodiments, the arms are configured to mate with features of existing substrate containers (e.g., attachment points for conventional substrate holders on a FOUP door).

[0059] In assembly, the block body 180 of the retainer bumper 120a is inserted into the receptacle 140. Because the lateral dimension 184 of the block body 180 may be oversized relative to the lateral inner dimension 152 and / or the minimum lateral dimension 158 of the recess 146, an interference fit exists between the receptacle 140 and the peripheral portion 133a of the block body 180. The interference forms a friction fit between the receptacle 140 and the block body 180 that retains the block body 180 within the receptacle 140 but allows the central region 134a to deflect relative to the mounting structure 130a when in use to prevent damage to the substrate 114.

[0060] In some embodiments, the resulting compression of the transverse dimension 184 of the retainer cushion 120a causes the retainer cushion 120a to bend to define a convexity in the direction of the thickness dimension 124. In some embodiments, the mounting structure 130a is configured to accommodate the convexity, for example, by providing a gap (not depicted) between the block body 180 and the base portion 144, or by an arcuate base portion 144 defining a convex boundary of the recess 146. In some embodiments, the bending causes the central region 134a of the contact surface 128a to bend outward from the receptacle 140. Functionally, the ridge portion 142 of the receptacle 140 applies a force to the perimeter 186 of the block body 180, which helps to retain the block body 180 within the receptacle 140.

[0061] refer to Figures 5 to 8 , a mounting structure 130b and a corresponding holder buffer 120b of a substrate holder 110b are depicted in an embodiment of the present invention. The mounting structure 130b includes a frame 200 having side members 202 separated by a plurality of cross members 204, each cross member 204 defining a mounting face 206. The holder buffer 120b is coupled to the mounting face 206 of each of the plurality of cross members 204. In some embodiments, the side members 202 and the plurality of cross members 204 are one-piece. In various embodiments, each of the cross members 204 is arcuate so that the mounting face 206 is convex. In the depicted embodiment, the mounting structure 130b includes a mounting feature 208 extending from the frame 200 for coupling the mounting structure 130b to the substrate container 100. The mounting structure 130b may include an axial member 212 bridging adjacent ones of the plurality of cross members 204.

[0062] In various embodiments, the plurality of cross members 204 include a plurality of extensions 214. At least one of the plurality of extensions 214 is disposed on one of the plurality of cross members 204. The plurality of extensions 214 extend through the thickness 124 ( Figure 7 ) or extends into the thickness 124 of the main body portion 122 ( Figure 8The body portion 122 of the retainer cushion 120b may define a plurality of mounting holes or apertures 216 ( Figure 6 ), each of which is positioned on the main body portion 122 for mating with a corresponding one of the plurality of extensions 214 and each of which is sized for friction fit with a corresponding one of the plurality of extensions 214.

[0063] refer to Fig. 9 and 10 , an embodiment of the present invention depicts a substrate holder 110c including a mounting structure 130c and a holder buffer 120c. The mounting structure 130c may have the same general form as described for the mounting structure 130b and include the same components and attributes as the mounting structure 130b. The difference between the mounting structures 130b and 130c is that the mounting structure 130c includes a concave mounting feature (e.g., the aperture 236) rather than a convex mounting feature (e.g., the extension 214).

[0064] In the depicted embodiment, the plurality of extensions 232 extend from the mounting face 234 of the body portion 122 in the direction of the thickness dimension 124. The plurality of cross members 204 define a plurality of apertures 236. In some embodiments, at least one of the plurality of apertures 236 is defined by each of the plurality of cross members 204. In one embodiment, the plurality of extensions 232 of the retainer cushion 120c and the plurality of apertures 236 of the cross members 204 are sized for a friction fit therebetween to secure the retainer cushion 120c to the mounting structure 130c ( Fig. 9 The extension portion 232 and the main body portion 122 may be formed in one piece.

[0065] In some embodiments, each of the plurality of extensions 232 of the retainer cushion 120c includes a neck portion 242 and a bulbous portion 244 distal to the neck portion 242, the neck portion 242 being disposed in a corresponding one of the plurality of apertures 236. The bulbous portion 244 of a given extension can be aligned to abut against a second face 246 of the traverse member 204 to secure the retainer cushion 120c to the traverse member 204. The second face 246 of a given traverse member 204 is opposite the mounting face 206.

[0066] refer to Figures 11 to 13 According to an embodiment of the present invention, the door 104 of the substrate container is modified to directly accommodate a given one of the disclosed retainer cushions. For example, the door 104 may include a receptacle 140 ( Fig.11 ), the cross member 204 and the extension 214 of the mounting structure 130b which are integral therewith ( Fig.12 ) or the cross member 204 and the aperture 236 ( Fig.13). The corresponding retainer cushion 120a, 120b, or 120c can then be coupled directly to the door 104 without the need for an intermediate mounting structure 130. In various embodiments, the mounting structure 130 is integrally formed with the door 104, for example, by an injection molding process. In other embodiments, the components are separately formed and made integral by, for example, a welding, bonding, or fusion process.

[0067] refer to Fig.14 and 15 , an embodiment of the present invention depicts a substrate holder 110d including a mounting structure 130d and a holder cushion 120d. Like the mounting structures 130b and 130c, the mounting structure 130d includes side members 202 separated by a cross member 204. Also like the mounting structures 130b and 130c, the mounting structure 130d and the holder cushion 120d may include complementary mounting features 252 (e.g., Figure 7 and 8 The extension 214 and the opening 216, or Fig. 9 and 10 The mounting structure 130d may also include a mounting feature 208 for coupling the mounting structure 130d to the substrate container 100. In the depicted embodiment, the mounting feature 208 is hook-shaped for mating with a retaining structure 254 protruding from the inner side of the door 104.

[0068] For mounting structure 130d and retainer buffer 120d, the retaining force applied to the residing substrate 114 is primarily through the stretching displacement of retainer buffer 120d in the axial direction 118. The axial stretching tensions retainer buffer 120d such that retainer buffer 120d acts as a stretched membrane that applies a radial force Fr to substrate 114. This is in contrast to mounting structures 130a, 130b, and 130c and retainer buffers 120a, 120b, and 120c, for which the primary retaining force is a reaction to the elastic compression and acts as a stretched membrane providing a secondary retaining force. In various embodiments, the cross members 204 are sized to deflect easily in anticipation of the resident substrate 114 being directly aligned with the cross members 204 so that the retainer buffer 120d can deflect and there is a spacing between the cross members 204 for the retainer buffer 120d to deflect when the resident substrate 114 is not aligned with one of the cross members 204.

[0069] refer to Figures 16 to 18, an embodiment of the present invention depicts a substrate holder 110e including a mounting structure 130e and a holder buffer 120e. Like the mounting structure 130b, the mounting structure 130e includes a frame 200 having side members 202 separated by cross members 204 and an axial member 212 bridging adjacent cross members 204. Also like the mounting structure 130b, the mounting structure 130e may include a mounting feature 208 extending therefrom.

[0070] Unlike the mounting structure 130b, not all cross members 204 separate or bridge the side members 202. Rather, only the first cross member 204a and the second cross member 204b of the plurality of cross members 204 separate or bridge the side members 202. In the depicted embodiment, the first cross member 204a and the second cross member 204b are the uppermost cross member and the lowermost cross member of the plurality of cross members 204. Also, in the depicted embodiment, the axial member 212 is aligned with and cooperates with the first cross member 204a and the second cross member 204b to define the inner frame 270. In some embodiments, a flange structure 272 extends from the inner frame 270, the flange structure defining the central opening 268. The flange structure includes a seat portion 274 and a transverse portion 276 and cooperates with the inner frame 270 to define an undercut 278.

[0071] The retainer cushion 120e is configured to couple with and bridge the flange structure 272. As with other disclosed retainer cushions 120, the retainer cushion 120e includes a main body portion 122 made of a flexible material. The retainer cushion 120e also includes opposing rail portions 282 extending from the main body portion 122. Alternatively, the retainer cushion includes a continuous rail portion 282 having opposing sides. Each rail portion 282 includes a lip 284 extending below the main body portion 122 and configured to fit within the undercut 278. The lip 284 and the main body portion 122 cooperate to define a slot 285. In the depicted embodiment, the rail portion 282 defines a perimeter 286 of the edge portion 133e. Also, in the depicted embodiment, the main body portion 122 of the retainer cushion 120e has a central region 134e that spans across the opening 268 without the need for additional supports. Alternatively, a support structure (not depicted) (e.g., a strap, laces, and / or a mesh structure) may bridge the opening 268 to provide additional resilient support to the main body portion 122 of the retainer cushion 120e. In some embodiments, the rail portion 282 is continuous, thereby surrounding the main body portion 122; in other embodiments, the two rail portions 282 extend only along opposite edges of the main body portion 122.

[0072] In assembly, the rail portion 282 of the retainer cushion 120e is coupled to the flange structure 272 to cover the opening 268. For configurations in which the rail portion 282 surrounds or substantially surrounds the body portion 122, the retainer cushion 120e snaps over the flange structure 272 of the mounting structure 130e, effectively forming a cap over the flange structure 272. To remove the retainer cushion 120e, for example prior to a washing process, the rail portion 282 is lifted or peeled away from the flange structure 272.

[0073] For configurations where the retainer buffer 120e includes two separate and opposing rail portions 282, the retainer buffer 120e can be slid over the flange structure 272 from one end. The flange structure 272 can include a protrusion 288 that increases the interference between the lateral portion 276 of the flange structure 272 and the slot 285 formed by the rail portion 282 of the retainer buffer 120e. The increased interference can help secure the retainer buffer 120e to the flange structure 272. To remove the retainer buffer 120e, the retainer buffer 120e is slid off the lateral portion 276 of the flange structure 272.

[0074] In operation, the body 122 of the retainer cushion 120e engages the edge of the resident substrate 114. In some embodiments, the flexible material of the body portion 122 of the retainer cushion 120e is a resilient foam material that relies on compression of the foam to apply radial force on the resident substrate. In other embodiments, the flexible material is an elastic material that stretches (similar to the retainer cushion 120d), becomes taut upon engagement with the resident substrate 114 to apply the substrate retention force. The embodiments are not mutually exclusive such that embodiments may rely on compression of the foam and stretching of the elastic material to apply the substrate retention force.

[0075] It is also contemplated to use a composite retainer cushion 120e where the body portion 122 includes an elastic base having an elastic foam material disposed over a face for contact with the resident substrate 114. The elastic foam material may be bonded to the elastic base by adhesive-free techniques such as fusion, welding, or overmolding.

[0076] refer to Fig.19 , an embodiment of the present invention depicts a substrate holder 110f including a mounting structure 130f and a holder buffer 120f. Like the mounting structures 130b to 130e, the mounting structure 130f includes side members 202 separated by cross members 204 and may include mounting features 208. The mounting structure 130f also includes a central axial member 300 supported by the cross member 204. The central axial member 300 defines an axially extending channel 302. The holder buffer 120f is disposed within the channel 302.

[0077] In the depicted embodiment, the retainer cushion 120f is tubular, and the channel 302 defines an arcuate or semicircular surface to conform to the tubular form. The mounting structure 130f may include clamps 306 disposed at opposite ends of the channel 302 that secure the retainer cushion 120f to the mounting structure 130f. The retainer cushion 120f may be formed from a foam tube or a hollow O-ring wire rod.

[0078] In operation, the holder buffer 120f protrudes from the mounting structure 130f to contact the wafer, similar to the holder buffer 120a of the substrate holder 110a.

[0079] refer to Fig. 20 , an embodiment of the present invention depicts a substrate holder 110g including a mounting structure 130g and a holder buffer 120g. The mounting structure 130g includes a mounting plate 320 and (like the mounting structures 130b to 130f) may include mounting features 208. A mounting rail 322 extends axially along the center of the mounting plate 320. The holder buffer 120g is arcuate and coupled to the mounting rail 322. In one embodiment, the holder buffer 120g includes an arcuate sheet buffer 324 formed by cutting and expanding a cylindrical tube. The expanded cylindrical tube is used to preload the arcuate sheet buffer 324 against the rail 322.

[0080] In operation, the holder buffer 120g extends from the mounting structure 130g to contact the wafer, similar to the holder buffer 120a of the substrate holder 110a.

[0081] Having described several illustrative embodiments of the present invention, it will be readily apparent to those skilled in the art that still other embodiments may be made and used within the scope of the appended claims. The numerous advantages of the present invention covered by this document have been set forth in the foregoing description. However, it will be understood that the present invention is merely illustrative in many respects. Changes may be made in detail (particularly with respect to the shape, size, and arrangement of parts) without exceeding the scope of the present invention. Of course, the scope of the present invention is defined in the language in which the appended claims are expressed.

Claims

1. A substrate holder for a substrate container, comprising: a retainer cushion comprising a body portion having an outer peripheral portion, a central region, and a thickness defining a thickness dimension, the body portion being formed of a flexible material compressible in the thickness dimension; and a mounting structure configured to secure the retainer cushion at the outer peripheral portion and to allow the central region to deflect relative to the mounting structure; Wherein the mounting structure includes a frame having side members separated by a plurality of one-piece cross members, each cross member defining a mounting surface, the retainer cushion being coupled to the mounting surface of each of the plurality of cross members. 2 . The substrate holder of claim 1 , wherein each of the plurality of traverse members is arcuate such that the mounting surface is concave or convex.

3. The substrate holder of claim 1, comprising mounting features extending from the frame for coupling the mounting structure to the substrate container.

4. The substrate holder of claim 1, comprising an axial member bridging adjacent ones of the plurality of traverse members.

5. A substrate holder according to claim 1, wherein the plurality of cross members include a plurality of extensions, at least one of the plurality of extensions being disposed on a corresponding one of the plurality of cross members, and the plurality of extensions extending into or through the thickness of the main body portion.

6. A substrate holder according to claim 5, wherein the main body portion of the holder buffer pad defines a plurality of mounting holes through the thickness of the main body portion, each hole being positioned on the main body portion for mating with a corresponding one of the plurality of extensions and each being sized for friction fit with the corresponding one of the plurality of extensions.

7. A substrate holder according to claim 1, comprising a plurality of extensions extending from the face of the main body portion in the direction of the thickness dimension, wherein the plurality of cross members define a plurality of orifices, at least one of the plurality of orifices being defined by each of the plurality of cross members, and wherein each of the extensions is sized and positioned on the main body portion to mate with the plurality of orifices.

8. The substrate holder of claim 7, wherein the plurality of protrusions and the plurality of apertures are sized for a friction fit therebetween to secure the holder buffer pad to the mounting structure, and wherein the protrusions are unitary with the body portion.

9. A substrate holder according to claim 7, wherein each of the plurality of extensions includes a neck portion and a bulbous portion at a distal end of the neck portion, the neck portion being disposed in a corresponding one of the plurality of orifices, the bulbous portion being aligned to abut against a second surface of the corresponding one of the plurality of cross members to secure the holder buffer pad to the cross member, the second surface being opposite to the mounting surface of the corresponding one of the plurality of cross members.

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