Substrate container with door gasket

Abstract

A gasket for a wafer container includes a closure body and a retention protrusion. The retention protrusion includes a retention segment extending from the closure body, a compression relief segment extending from the retention segment, and a bead disposed at an end of the compression relief segment. The compression relief segment has a cross-sectional width that is less than a cross-sectional width of the retention segment. The bead has a shape that includes a portion having a width that is greater than the cross-sectional width of the gland at a corresponding depth within the gland. The gasket can be provided on a wafer container or a door of the wafer container.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to substrate containers, and in particular to containers with gaskets having shapes that improve sealing and retention of the gasket. [Background technology]

[0002] Wafer containers define a microenvironment for storing and processing wafers, such as semiconductor wafers. To define the microenvironment, wafer containers typically include an open side and a door that closes the open side. A seal, such as a gasket, can be formed between the door and another portion of the body. The gasket can be retained within a gland formed in a portion of the wafer container or in the door. Summary of the Invention

[0003] FIELD OF THE DISCLOSURE The present disclosure relates to substrate containers, and in particular to containers with gaskets having shapes that improve sealing and retention of the gasket.

[0004] The gaskets according to the embodiments provide significantly stronger retention relative to the required insertion force. Therefore, the gaskets can be more securely secured without increasing the insertion force or otherwise complicating the assembly of the gasket into the wafer container or wafer container door. This reduces the risk of gasket slippage and ensures the quality of the seal. The gaskets according to the embodiments can also improve sealing effectiveness.

[0005] In one embodiment, a door for a wafer container includes a door plate including a gland configured to receive a portion of the gasket, and a gasket including a compression member. The gasket includes a closure body and a retention protrusion. The retention protrusion includes a retention segment extending from the closure body. The retention segment has a cross-sectional width equal to or less than the cross-sectional width of the gland at a corresponding depth within the gland. The retention protrusion further includes a compression relief segment extending from the retention segment. The compression relief segment has a cross-sectional width less than the cross-sectional width of the retention segment. The retention protrusion further includes a bead disposed at an end of the compression relief segment. The bead has a maximum cross-sectional width greater than the cross-sectional width of the gland at a corresponding depth within the gland.

[0006] In one embodiment, the gasket has a retention force to insertion force ratio of 0.5 to 1.0, where the retention force is the force required to remove the gasket from the gland and the insertion force is the force required to fully insert the retention protrusion into the gland.

[0007] In one embodiment, when the door is attached to the wafer container, the conductance through the door seam is less than 0.02.

[0008] In one embodiment, the retention segment forms at least half the total length of the retention protrusion.

[0009] In one embodiment, the retention segment has a length at least twice the overall length of the compression relief segment.

[0010] In one embodiment, the gasket is formed from a thermoplastic elastomer having a Shore A hardness of 50 to 80 durometer.

[0011] In one embodiment, the cross-sectional width of the retention segment is 5% to 15% smaller than the cross-sectional width of the gland where the retention segment merges with the seal body.

[0012] In one embodiment, the cross-sectional width of the bead at its widest point is 5% to 12% greater than the cross-sectional width of the gland at the corresponding depth within the gland.

[0013] In one embodiment, the cross-sectional width of the compression relief segment is 5% to 15% less than the cross-sectional width of the retention segment.

[0014] In one embodiment, a front-opening wafer container includes a container body having a front opening defined by a door frame and a door configured to attach to the door frame. The door includes a door plate with a gland configured to receive a portion of the gasket, and a gasket containing a compression member. The gasket includes a seal body and a retention protrusion. The retention protrusion includes a retention segment extending from the seal body. The retention segment has a cross-sectional width equal to or less than the cross-sectional width of the gland at a corresponding depth within the gland. The retention protrusion further includes a compression relief segment extending from the retention segment. The compression relief segment has a cross-sectional width smaller than the cross-sectional width of the retention segment. The retention protrusion further includes a bead disposed at an end of the compression relief segment. The bead has a maximum cross-sectional width greater than the cross-sectional width of the gland at a corresponding depth within the gland. The gasket is configured to form a seal between the door and the door frame.

[0015] In one embodiment of the wafer container, the gasket has a retention force to insertion force ratio of 0.6 to 1.0.

[0016] In one embodiment of the wafer container, when the door is attached to the wafer container, the conductance through the door seam is less than 0.02.

[0017] In one embodiment of the wafer container, the retention segments form at least half the overall length of the retention protrusions.

[0018] In one embodiment of the wafer container, the retention segment has a length at least twice the overall length of the compression relief segment.

[0019] In one embodiment of the wafer container, the gasket is formed from a thermoplastic elastomer having a Shore A hardness of 60 to 90 durometers.

[0020] In one embodiment of the wafer container, the cross-sectional width of the retention segment is 5% to 15% smaller than the cross-sectional width of the gland at the location where the retention segment merges with the closure body.

[0021] In one embodiment of the wafer container, the cross-sectional width of the bead at its widest point is 5% to 12% greater than the cross-sectional width of the gland at a corresponding depth within the gland.

[0022] In one embodiment of the wafer container, the cross-sectional width of the compression relief segment is 5% to 15% less than the cross-sectional width of the retention segment. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is an exploded view of a wafer container according to one embodiment. [Figure 2] 1 is a cross-sectional view of a gasket and wafer container door according to one embodiment. [Figure 3] 10A and 10B are views of retention protrusions of a gasket according to one embodiment. [Figure 4] 10A and 10B are views of retention protrusions of a gasket according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] FIELD OF THE DISCLOSURE The present disclosure relates to substrate containers, and in particular to containers with gaskets having shapes that improve sealing and retention of the gasket.

[0025] 1 shows an exploded view of a wafer container according to one embodiment. The wafer container 100 comprises a container body 102 having an open end 104. The wafer container 100 further comprises a door 106. A gasket 108 may be used to seal where the door 106 and container body 102 mate to close the open end 104.

[0026] The wafer container 100 is a container used to process, transport, and / or store wafers, such as semiconductor wafers. The wafer container 100 may be a front-opening container, such as a front-opening integrated pod (FOUP). A container body 102 defines an interior space within the wafer container 100, and an open end 104 is provided on one side of the container body 102. The open end 104 may allow wafers to be placed in and / or removed from the interior space defined by the container body 102. A door 106 may be used to close the open end 104. When the open end 104 is closed by the door 106, a seal may be formed, such that the interior space within the wafer container 100 forms a microenvironment that is protected from contaminants in the environment surrounding the wafer container 100. The seal may be provided by a gasket 108. The gasket 108 is configured to form a seal between the container body 102 and the door 106 when the door 106 closes the open end 104. The gasket 108 may be fabricated from any material suitable for forming a seal, such as a polymeric material. In one embodiment, the gasket 108 comprises a thermoplastic elastomer having a Shore A hardness of 50-80 durometers. In one embodiment, the gasket 108 is formed entirely from a thermoplastic elastomer having a Shore A hardness of approximately 50-80 durometers.

[0027] 1 , the door 106 includes a gland 110 formed on a surface of the door 106 that faces the container body 102 when assembled to close the open end 104. The gland 110 is configured to retain the gasket 108. The gland 110 is a groove configured to accommodate a protrusion from the gasket 108. In one embodiment, the gland 110 is tapered such that the cross-sectional width of the gland 110 decreases as the gland 110 moves from the surface of the door 106 into the body of the door 106. While the gland 110 is shown as being disposed on the door 106, it should be understood that the gland may be located in any location suitable for retaining the gasket 108 so as to form a seal between the door 106 and the container body 102, such as, for example, on the periphery of the open end 104.

[0028] 2 shows a cross-sectional view of a gasket and wafer container door according to one embodiment. Wafer container door 200 includes a gland 202 and a gasket 204. Gasket 204 includes a seal body 206 and a retention protrusion 208. Retention protrusion 208 includes a retention segment 210, a compression relief segment 212, and a bead 214.

[0029] The wafer container door 200 is a door configured to close a wafer container, such as the door 106 of the wafer container 100, and the door closes the open end 104 as shown in FIG. 1 and described above. The gland 202 is a groove formed in the wafer container door 200. In one embodiment, the sides of the gland 202 are parallel to one another, and the groove has a constant width throughout its depth. In one embodiment, the sides of the gland 202 are angled toward one another so that the groove has a tapered shape, with the width of the groove decreasing with depth. The relative thickness of each segment of the retention protrusion 208 may correspond to the width of the gland 202 at the depth that the segment, or an associated portion thereof, occupies when the retention protrusion 208 is fully inserted into the gland 202.

[0030] The gasket 204 is configured to form a seal between the wafer container door 200 and a corresponding wafer container (not shown), such as the wafer container 100 described above and shown in FIG. 1 . The gasket 204 is configured to be retained on the wafer container door 200 by an interference fit between the retention protrusions 208 and the gland 202. The gasket 204 may be fabricated from any material suitable for forming a seal, such as a polymeric material. In one embodiment, the gasket 204 includes a thermoplastic elastomer having a Shore A hardness of 50-80 durometers. In one embodiment, the gasket 204 is formed entirely from a thermoplastic elastomer having a Shore A hardness of 50-80 durometers.

[0031] The seal body 206 is a portion of the gasket 204 configured to be compressed between the door 200 and the wafer container to form a seal. The seal body 206 may have any shape and thickness suitable for such compression. The seal body 204 may be configured to be preloaded by contact with the wafer container door 200. In one embodiment, the seal body 206 may be configured such that when the gasket 204 is retained within the gland 202, a leading edge of the seal body 206 is angled away from the door 200. In one embodiment, at least a portion of the seal body 206 may be angled relative to the retention protrusion 208 to form an acute angle with the retention protrusion 208.

[0032] The retention protrusion 208 is configured to be inserted into the gland 202 to retain the gasket 204 on the door 200. The retention protrusion 208 is configured to compress at least a segment of the retention protrusion 208 with the walls of the gland 202 to create a retention force. Compression of the retention protrusion by the gland 202 may also create a resistance force against insertion of the retention protrusion 208 into the gland 202. The retention protrusion 208 includes a retention segment 210, a compression relief segment 212, and a bead 214.

[0033] The retention segment 210 is a segment of the retention protrusion 208 that connects to the closure body 206. At the closure body 206, the retention segment 210 may have a cross-sectional width that is smaller than the width of the opening in the gland 202. In one embodiment, the cross-sectional width of the retention segment at the closure body 206 may be 5% to 15% smaller than the cross-sectional width of the opening in the gland 202. A portion of the retention segment 210 may be configured to be inserted into the gland 202. The portion of the retention segment 210 configured to be inserted into the gland 202 may have a cross-sectional width that is approximately equal to the cross-sectional width of the gland 202 at a depth corresponding to the position of the retention segment 210 when the gasket 204 is inserted into the gland 202. In one embodiment, the retention segment 210 forms at least half the total length of the retention protrusion 208. In one embodiment, the retention segment 210 has a length that is at least twice the length of the compression relief segment 212.

[0034] Compression relief segment 212 is a segment of retention protrusion 208 that extends from retention segment 210 to bead 214. Compression relief segment 212 is a segment of retention protrusion 208 that has a cross-sectional thickness that is less than the cross-sectional width of gland 202 at a corresponding depth. In one embodiment of gland 202 having a typical width for a standard FOUP design, compression relief segment 212 has a thickness that is approximately 0.15 mm less than the thickness of retention segment 210. In one embodiment, the overall length of compression relief segment 212 is less than or equal to half the overall length of retention segment 210.

[0035] The bead 214 is provided at an end of the retention protrusion 208, at the end of the compression relief segment 212 opposite where the compression relief segment 212 joins with the retention segment 210. The bead 214 is a portion of the retention protrusion 208 that is insertable into the gland 202 and configured to form an interference therewith. The bead 214 includes a tip 216 having a cross-sectional width smaller than the opening of the gland 202, thereby allowing the tip 216 to be introduced into the gland 202. The bead 214 further includes at least one interference-fit portion 218 having a cross-sectional width greater than the cross-sectional width of a corresponding depth within the gland 202. The interference-fit portion 218 may comprise the widest point of the bead 214 in terms of cross-sectional width. The bead may have any suitable shape, such as rounded or tapered, extending from the tip 216 to the interference-fit portion 218. The interference fit portion 218 can be sized to be compressed by the wall of the gland 202 when the retention protrusion 208 is inserted into the gland 202. In one embodiment, the interference fit portion 218 has or includes a widest point with a cross-sectional width that is 5% to 12% greater than the cross-sectional width of the gland at a corresponding depth within the gland. In one embodiment configured for use with a standard FOUP design, the interference fit portion 218 has a cross-sectional width that is approximately 0.15 mm greater than the cross-sectional width of the gland at a corresponding depth within the gland. In one embodiment, the bead 214 has a rounded shape with a diameter that corresponds to the maximum cross-sectional width of the interference fit portion 218. In one embodiment, the bead 214 can be positioned relative to the compression relief segment 212 such that the interference fit portion 218 is continuous with a line formed on one side by the compression relief segment 212 and extends outwardly to an opposite side of the compression relief segment. In one embodiment, the bead 214 is positioned relative to the compression relief segment 212 such that the interference fit portion 218, when viewed in cross section, extends outwardly relative to both sides of the compression relief segment 212. Further non-limiting examples of the bead 214 are included in the retention protrusions 300 and 400 shown in Figures 3 and 4 and described below.Compressing the interference fit portion 218 of the bead 214 can cause some or all of the retention protrusion 208 to expand and form an interference fit with the gland 202, thereby retaining the gasket 204 within the gland 202 and forming a seal that inhibits flow from one side of the gland 202 to the other side of the gland 202 when the door 200 is attached to a wafer container.

[0036] The retention protrusion 208, including the retention segment 210, compression relief segment 212, and bead 214, can exert a relatively large retention force compared to the insertion force of the gasket 204. The retention force is the amount of force required to remove the gasket 204 from the gland 202. The insertion force is the amount of force required to fully insert the gasket 204 into the gland 202. In one embodiment, the ratio of the retention force to the insertion force can range from 0.5 to 1.0. By comparison, standard gasket designs for wafer containers have a retention force ratio of about 0.25 to about 0.35. Thus, the gasket 204 can provide easier assembly and / or stronger retention of the gasket 204 within the gland 202 compared to standard gasket designs.

[0037] A gasket was prepared with a retention protrusion 208. Three embodiments were prepared, each including a retention segment 210, a compression relief segment 212, and a bead 214. The bead shape and the relative length of each segment were consistent across the three embodiments. The only variation across the example embodiments was the change in cross-sectional width of one or more segments of the retention protrusion. Among the embodiments shown in Table 1, Embodiment 2 has a retention segment and bead with a cross-sectional width that is 0.05 mm, or approximately 2.5%, larger than that of Embodiment 1. Embodiment 3 has the same cross-sectional width in the retention segment as Embodiment 1, but with a bead that is 0.1 mm, or approximately 5%, larger than that of Embodiment 1. The force in Newtons required to fully insert each embodiment into the gland of the corresponding wafer container door was measured and recorded in Table 1 as the insertion value. The force in Newtons required to remove the fully inserted embodiment from the gland was then measured and recorded in Table 1 as the retention value. The ratio of the retention value divided by the insertion value is shown as the ratio value. The same insertion and retention force tests were then performed on a proven product of record (POR) currently used as a seal for wafer container doors, which has sloped walls formed to correspond to the shape of the gland, without a separate compression relief segment or bead as in Examples 1-3. TIFF0007805378000001.tif40170

[0038] As can be seen in Table 1, while the ratio of retention force to compression force varies across each embodiment as the individual cross-sectional widths of the segments are varied, the ratio is significantly greater in all embodiments compared to POR, at least in part due to the individual provision and placement of compression relief segments and beads.

[0039] Additionally, the gasket 204 can provide a stronger seal when the door 200 is attached to a wafer container compared to standard gasket designs. For example, the conductance through a door according to one embodiment attached to a wafer container can be 0.02 or less.

[0040] FIG. 3 illustrates a retention protrusion of a gasket according to one embodiment. The gasket 300 includes a seal body 302 and a retention protrusion 304. The retention protrusion 304 includes a retention segment 306, a compression relief segment 308, and a bead 310. In the embodiment shown in FIG. 3, the bead 310 includes a tip 312 and an interference-fit portion 314. The cross-sectional shape of the bead 310 may be, for example, a generally rhomboid shape with rounded corners. The interference-fit portion 314 includes an interference projection 316 that extends outward relative to a first side 318 of the retention protrusion 304. In the gasket 300, a second side 320 opposite the first side 318 is continuously tapered along the entire length of the retention protrusion 304.

[0041] FIG. 4 illustrates a retention protrusion of a gasket according to one embodiment. The gasket 400 includes a seal body 402 and a retention protrusion 404. The retention protrusion 404 includes a retention segment 406, a compression relief segment 408, and a bead 410. In the embodiment shown in FIG. 4, the bead 410 includes a tip 412 and an interference-fit portion 414. The bead 410 has a generally circular cross-sectional shape. In the gasket 400, the generally circular cross-sectional shape of the bead 410 is offset from the center of the circular cross-sectional shape so that a first side 418 of the retention protrusion 404 tapers continuously along the entire length of the retention protrusion 404. The interference-fit portion 414 includes an interference projection 416 extending outwardly to a second side 420, the second side 420 being opposite the first side 418 of the retention protrusion 404. 4, the gasket 400 is inserted into the gland 422. When the gasket 400 is inserted into the gland 422, the retention segments 406 and the beads 410 are compressed, and the compression relief segments 408 expand to further fill the gland 422 due to compression from objects surrounding the retention segments 406 and the beads 410.

[0042] Aspects It is understood that any of embodiments 1-9 can be combined with any of embodiments 10-18.

[0043] Aspect 1: A door for a wafer container, comprising: a door plate including a gland configured to receive a portion of the gasket; A gasket containing a compression material Equipped with The gasket is A sealing portion main body; Retaining protrusion and Equipped with The retaining protrusion is a retention segment extending from the closure body, the retention segment having a cross-sectional width equal to or less than the cross-sectional width of the gland at a corresponding depth within the gland; a compression relief segment extending from the retention segment, the compression relief segment having a cross-sectional width less than a cross-sectional width of the retention segment; a bead located at the end of the compression relief segment, the maximum cross-sectional width of which is greater than the cross-sectional width of the gland at the corresponding depth within the gland; A door equipped with:

[0044] Aspect 2. The door according to aspect 1, wherein the gasket has a retention force to insertion force ratio of 0.5 to 1.0, the retention force being the force required to remove the gasket from the gland and the insertion force being the force required to fully insert the retention protrusion into the gland.

[0045] Aspect 3: The door according to aspect 1 or 2, wherein when the door is attached to the wafer container, the conductance through the door seam is less than 0.02.

[0046] Embodiment 4. The door according to any of embodiments 1 to 3, wherein the retention segment forms at least 1 / 2 of the overall length of the retention protrusion.

[0047] Embodiment 5. The door according to any of embodiments 1 to 4, wherein the retention segment has a length at least twice the overall length of the compression relief segment.

[0048] Aspect 6. The door according to any of Aspects 1 to 5, wherein the gasket is formed from a thermoplastic elastomer having a Shore A hardness of 50 to 80 durometers.

[0049] Aspect 7: The door according to any one of Aspects 1 to 6, wherein the cross-sectional width of the retaining segment is 5% to 15% smaller than the cross-sectional width of the gland at the location where the retaining segment joins with the sealing portion body.

[0050] Aspect 8. A door according to any of aspects 1 to 7, wherein the cross-sectional width of the bead at its widest point is 5% to 12% greater than the cross-sectional width of the gland at the corresponding depth within the gland.

[0051] Aspect 9. The door according to any of aspects 1 to 8, wherein the cross-sectional width of the compression relief segment is 5% to 15% less than the cross-sectional width of the retention segment.

[0052] Aspect 10: A container body having a front opening, the front opening being defined by a door frame; a door configured to be attached to a door frame; A front-opening wafer container comprising: The door, a door plate including a gland configured to receive a portion of the gasket; A gasket containing a compression material Equipped with The gasket is A sealing portion main body; Retaining protrusion and Equipped with The retaining protrusion is a retention segment extending from the closure body, the retention segment having a cross-sectional width equal to or less than the cross-sectional width of the gland at a corresponding depth within the gland; a compression relief segment extending from the retention segment, the compression relief segment having a cross-sectional width less than a cross-sectional width of the retention segment; a bead located at the end of the compression relief segment, the maximum cross-sectional width of which is greater than the cross-sectional width of the gland at the corresponding depth within the gland; Equipped with The gasket is configured to form a seal between the door and the door frame. Front-opening wafer container.

[0053] Embodiment 11. The front-opening wafer container according to embodiment 10, wherein the gasket has a retention force to insertion force ratio of 0.6 to 1.0.

[0054] Aspect 12: The front-opening wafer container according to aspect 10 or 11, wherein when the door is attached to the wafer container, the conductance through the door seam is less than 0.02.

[0055] Embodiment 13. The front-opening wafer container according to any of embodiments 10 to 12, wherein the retention segments form at least one-half of the overall length of the retention protrusions.

[0056] Embodiment 14. The front-opening wafer container according to any of embodiments 10 to 13, wherein the retention segment has a length at least twice the overall length of the compression relief segment.

[0057] Aspect 15 The front-opening wafer container according to any of Aspects 10 to 14, wherein the gasket is formed from a thermoplastic elastomer having a Shore A hardness of 60 to 90 durometers.

[0058] Aspect 16: A front-opening wafer container according to any one of aspects 10 to 15, wherein the cross-sectional width of the retention segment is 5% to 15% smaller than the cross-sectional width of the gland at the location where the retention segment joins with the sealing portion body.

[0059] Aspect 17: The front-opening wafer container according to any of aspects 10 to 16, wherein the cross-sectional width of the bead at its widest point is 5% to 12% greater than the cross-sectional width of the gland at the corresponding depth within the gland.

[0060] Embodiment 18: The front-opening wafer container according to any of embodiments 10 to 17, wherein the cross-sectional width of the compression relief segment is 5% to 15% less than the cross-sectional width of the retention segment.

[0061] The examples disclosed in this application are to be considered in all respects as illustrative and not limiting. The scope of the invention is indicated by the appended claims, rather than by the foregoing description, and all variations that come within the meaning and range of equivalents of the claims are intended to be embraced therein.

Claims

1. 1. A door for a wafer container, comprising: a door plate including a gland configured to receive a portion of the gasket; A gasket containing a compression material Equipped with The gasket is A sealing portion main body; Retaining protrusion and Equipped with The retaining protrusion is a retention segment extending from the closure body, the retention segment having a cross-sectional width equal to or less than the cross-sectional width of the gland at a corresponding depth within the gland; a compression relief segment extending from the retention segment, the compression relief segment having a cross-sectional width less than a cross-sectional width of the retention segment; a bead disposed at an end of the compression relief segment, the bead having a maximum cross-sectional width greater than the cross-sectional width of the gland at a corresponding depth within the gland; Equipped with door.

2. a container body having a front opening, the front opening being defined by a door frame; a door configured to be attached to the door frame; A front-opening wafer container comprising: The door, a door plate including a gland configured to receive a portion of the gasket; A gasket containing a compression material Equipped with The gasket is A sealing portion main body; Retaining protrusion and Equipped with The retaining protrusion is a retention segment extending from the closure body, the retention segment having a cross-sectional width equal to or less than the cross-sectional width of the gland at a corresponding depth within the gland; a compression relief segment extending from the retention segment, the compression relief segment having a cross-sectional width less than a cross-sectional width of the retention segment; a bead disposed at an end of the compression relief segment, the bead having a maximum cross-sectional width greater than the cross-sectional width of the gland at a corresponding depth within the gland; Equipped with the gasket is configured to form a seal between the door and the door frame. Front-opening wafer container.

3. 10. The door of claim 1, wherein the gasket has a retention force to insertion force ratio of 0.5 to 1.0, the retention force being the force required to remove the gasket from the gland and the insertion force being the force required to fully insert the retention protrusion into the gland.

4. The door of claim 1 , wherein the retention segment forms at least half the overall length of the retention protrusion.

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