Purge port filter support

Abstract

The front-opening unified pod includes a housing and a purge port within the housing. The purge port includes a filter membrane and a purge filter support. The purge filter support includes an outer ring structure and a support frame feature. The support frame extends from the outer ring structure. The outer ring structure includes a plurality of supports providing a support surface for the filter membrane. One or more of the supports each increase in thickness from a thickness of the upper support surface. The purge filter support includes an outer ring structure, one or more openings, and a support frame extending from the outer ring structure. The support frame includes supports providing a support surface configured to contact and support the filter membrane. The one or more supports each increase in thickness from a first thickness of the upper support surface.

Description

[Technical Field]

[0001] Priority This disclosure claims priority to U.S. Provisional Patent Application No. 63 / 249,416, filed September 28, 2021. The priority document is incorporated by reference.

[0002] The present disclosure relates to a purge port of a FOUP, and more particularly, to a filter support used in a purge port of a FOUP. [Background technology]

[0003] Semiconductor devices can be produced from wafer substrates. Wafer substrates, or simply wafers, undergo a series of manufacturing steps. For example, manufacturing steps can include, but are not limited to, deposition of material layers, doping, etching, or chemical or physical reactions of substrate materials. Before, during, or after manufacturing, wafers can be stored and transported in one or more front-opening unified pods ("FOUPs"). For some manufacturing steps, wafers can be processed while still inside the FOUP. The FOUP can include one or more purge ports that supply purge gas to the interior of the FOUP. For example, purge gas can be supplied to maintain the interior of the FOUP at a positive pressure (e.g., a pressure above the pressure of the external environment, a pressure above atmospheric pressure) while the FOUP is open. Summary of the Invention

[0004] In one embodiment, the purge filter support includes an outer ring structure, a support frame, and one or more openings. The support frame extends inward from the outer ring structure. The support frame includes a plurality of supports providing an upper support surface. The upper support surface is configured to contact and support a filter membrane within a purge port of the FOUP. The supports include one or more supports, each increasing in thickness from a first thickness at the upper support surface. One or more openings extend through the support frame between the supports.

[0005] In one embodiment, the FOUP includes a housing and a purge port extending through the housing. The purge port includes a filter membrane and a purge filter support. The purge filter support includes an outer ring structure, a support frame, and one or more openings extending through the support frame. The outer ring structure contacts a periphery of the filter membrane. The support frame extends inward from the outer ring structure and includes a plurality of supports. The supports provide an upper support surface. One or more of the supports each increase in thickness from a first thickness at the upper support surface. A flow of purge gas through the purge port presses the filter membrane against the upper support surface. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a bottom perspective view of an embodiment of a front-opening unified pod (FOUP). [Figure 2] 2 is a partial cross-sectional view of a FOUP taken along line II-II of FIG. 1, according to one embodiment. [Figure 3] 3 is a cross-sectional view of a purge filter of the FOUP of FIG. 2 according to one embodiment. [Figure 4] FIG. 1 is a top perspective view illustrating one embodiment of a filter support for a purge filter in a FOUP. [Figure 5] 5 is a cross-sectional view of the filter support taken along line VV of FIG. 4, according to one embodiment. [Figure 6] 10 is a top perspective view illustrating another embodiment of a filter support for a purge filter in a FOUP. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0007] Like numbers refer to like features.

[0008] The present disclosure relates to a purge port of a FOUP, and more particularly, to a filter support used in a purge port of a FOUP.

[0009] FIG. 1 is a bottom perspective view of one embodiment of a front-opening unified pod ("FOUP"). FOUP 1 includes a housing 2. Housing 1 includes a front opening 3 and a front door 4. Door 4 covers front opening 3, and FOUP 1 can be accessed by moving (e.g., opening, removing) door 4. Housing 2 includes a bottom 6 having a purge port 10. Purge port 10 extends through housing 2. FOUP 1 can include one or more purge ports 10. For example, FOUP 1 in FIG. 1 includes two purge ports 10. In one embodiment, FOUP 1 may include a different number of purge ports 10 (e.g., one, three, etc.).

[0010] Figure 2 shows a partial cross-section of FOUP 1 taken along line II-II of Figure 1, according to one embodiment. Figure 2 shows a purge port 10 of FOUP 1. Purge port 10 is located in the bottom 6 of FOUP 1. Purge port 10 is disposed in an opening 14 in the bottom 6 of housing 2. Purge port 10 is disposed in opening 14 in a manner that blocks opening 14 (e.g., fluid can only pass through opening 14 by passing through purge port 10). Purge port 10 extends through housing 2 of FOUP 1 to an interior space 12 of FOUP 1.

[0011] FOUP 1 is configured to support one or more semiconductor substrates (not shown) within its interior space 12. In one embodiment, the FOUP is configured to support multiple semiconductor substrates. Purge port 10 is for supplying a purge gas to the interior 12 of FOUP 1. For example, the purge gas supplied through purge port 10 may include, but is not limited to, a generally inert gas (e.g., nitrogen), filtered air (e.g., clean dry air), etc. FIG. 2 includes a dotted arrow indicating the approximate direction of flow of the purge gas through purge port 10.

[0012] As shown in FIG. 2 , the purge port 10 includes an upper retaining member 20A, a lower retaining member 20B, a check valve 24, and a purge filter 30. The retaining members 20A and 20B contact the housing 2 (e.g., contact the sidewalls of the opening 14) and retain the purge port 10 within the opening 14. The check valve 24 and the purge filter 30 are configured to be held in place by the retaining members 20A and 20B. In one embodiment, the purge port 10 may include a single retaining member 20A and 20B, or the retaining members 20A and 20B may be a single piece. As the purge gas flows through the purge port 10, it passes through the purge filter 30. The purge filter 30 is configured to filter solid particles from the purge gas. The purge filter 30 is described in more detail below.

[0013] The check valve 24 may include a grommet 26 configured to mate with a purge nozzle (not shown) that supplies purge gas to the FOUP 1 and the purge port 10. The check valve 24 is configured to remain sealed at atmospheric pressure. When pressurized purge gas (e.g., having a pressure greater than atmospheric pressure) is supplied to the purge port 10, the pressure causes the check valve 24 to open, allowing the purge gas to flow through the purge port 10 and into the interior volume 12 of the FOUP 1. In one embodiment, the purge gas flows through the purge port 10 at up to 1000 liters per minute (LPM). In one embodiment, the purge gas flows through the purge port 10 at 30-1000 LPM. In one embodiment, the purge gas flows through the purge port 10 at up to 500 LPM. In one embodiment, the purge gas flows through the purge port 10 at up to 300 LPM. In one embodiment, the purge gas flows through the purge port 10 at 200 LPM or more. In one embodiment, the purge gas flows through the purge port 10 at 100 LPM or more.

[0014] FIG. 3 shows an enlarged view of the purge filter 30 of FIG. 2. The purge filter 30 includes a filter membrane 32 and a pair of filter supports 34. The filter membrane 32 is sandwiched between the pair of filter supports 34 in the flow direction D1. Each filter support 34 includes an outer ring structure 36 and a support frame 38 extending inward from the outer ring structure 36. Each outer ring structure 36 contacts the filter membrane 32. The periphery 33 of the filter membrane 32 is supported between the two outer ring structures 36 of the filter support 34. For example, the periphery 33 of the filter membrane 32 is sandwiched between the two outer ring structures 36 of the filter support 34 as shown in FIG. 3. In one embodiment, one of the filter supports 34 (e.g., the lower filter support 34 in FIG. 2) may be incorporated into the retaining portion 20B or the housing 2. It should be understood that the "ring structure" is not limited to circular and elliptical shapes, but includes other loop shapes such as square, rectangular, and triangular.

[0015] The support frame 38 includes a plurality of supports 40. For example, the supports 40 form the support frame 38. Each filter support 34 includes an upper support surface 42 that contacts and supports the filter membrane 32. In particular, the upper support surface 42 is configured to provide support for a central portion of the filter membrane 32 through which the purge gas passes (e.g., an inner portion of the filter membrane 32 other than the peripheral edge that is not sandwiched between the outer ring structures 36). The flow of purge gas through the purge ports 10 presses the filter membrane 32 against the upper support surface 42 of the filter support 34. The support frame 38 also has a lower surface 43 formed by the plurality of supports 40. The lower surface 43 is disposed on the opposite side of the plurality of supports from the upper support surface 43A.

[0016] Figure 4 is a top perspective view of a filter support 34 according to one embodiment. For example, the filter support 34 of Figure 4 may be the upper filter support of Figure 3. As described above, the filter support 34 includes an outer ring structure 36 and a plurality of supports 40 forming a support frame 38 extending radially inward from the outer ring structure 36. The supports 40 provide an upper support surface 42 of the filter support 34. For example, each support 40 provides a portion of the upper support surface 42. Each support 40 is configured to contact the filter membrane 32 within the purge filter 30.

[0017] As shown in the illustrated embodiment, the support 40 can include an inner ring structure 44 and ribs 46. The inner ring structure 44 and the ribs 46 can form a support frame 38, as shown in FIG. 4 . The inner ring structure 44 is disposed within the outer ring structure 36. The inner ring structure 44 is connected to the outer ring structure 36 by the ribs 46. Each rib 36 extends from the outer ring structure 36 to the inner ring structure 44. The outer ring structure 36 also includes one or more side walls 62 that define an inlet opening 64 for the filter support 34. The filter membrane 32 is disposed across the inlet opening 64.

[0018] The filter support 34 includes one or more openings 48 extending through the support frame 38 between the supports 40. For example, the openings 48 extend through the support frame 38 by extending between at least two of the supports 40. The openings 48 allow purge gas to pass through the filter support 34. As shown in FIG. 4 , the openings 48 may include a central opening 48A extending through the inner ring structure 44. The openings 48 may also include openings 48B extending through the filter support 34 between the outer ring structure 36 and the inner ring structure 44, respectively.

[0019] 4, the overlap between the support frame 38 and the inlet opening 64 in a direction perpendicular to the upper support surface 42 (e.g., in the flow direction D1) is greater than 20%. In one embodiment, the overlap between the support frame 38 and the inlet opening 64 may be greater than 25%. In another embodiment, the overlap between the support frame 38 and the inlet opening 64 may be greater than 30%.

[0020] FIG. 5 shows a cross section of the filter support 34 taken along line VV in FIG. 4. The plurality of supports 40 includes a first support 40-1. The first support 40-1 includes an upper support surface 42 and a lower surface 43 (e.g., a portion of the upper support surface 42 and a portion of the lower surface 43). The lower surface 43 is disposed on the opposite side of the first support 40-1 from the upper support surface 42. For example, the lower surface 43 and the upper support surface 42 are disposed on opposite sides in the purge flow direction D1. It should be understood that "upper" and "lower" with respect to the surfaces of the support refer only to the filter support 34. Therefore, the upper support surface 42 may not correspond to other relative directions / surfaces when used with the purge port 10. For example, in the upper filter support 34 in the purge filter 20 of FIG. 2, the upper support surface 42 faces downward (e.g., in direction D2, facing the same or similar direction as the bottom 6) and the lower surface 43 faces upward (e.g., in direction D1, facing the same or similar direction as the top of the housing 2).

[0021] As shown in FIG. 4 , the first support 40-1 has a varying thickness. The thickness of the first support 40-1 varies as one progresses from the upper support surface 42 into the first support 40-1 (e.g., as one progresses in a direction D2 perpendicular to the upper support surface 42, or as one progresses in a direction away from the upper support surface 42 along the purge flow direction D1). The thickness of the first support 40-1 extends to or approximately parallel to the upper support surface 42 on the first support 40-1 (e.g., the thickness is measured along a plane defined by the upper support surface 42 on the first support 40-1). For example, the thickness of the first support 40, in one embodiment, is measured parallel to the filter membrane 32 of the assembled purge filter 10.

[0022] The first support 40-1 has a first thickness T1 relative to the upper support surface 42 on the support 40-1. The first thickness T1 is the thickness of the first support 40-1 at the upper support surface 42. As shown in FIG. 5, the thickness of the first support 40-1 increases from the first thickness T1. The first thickness T1 can be 0.5 mm or less. In one embodiment, the first thickness T1 may be 0.25 mm or less. In one embodiment, the first thickness T1 may be 0.2 mm or less. In one embodiment, the first thickness T1 may be 0.15 mm or less.

[0023] The first support 40-1 also has a second thickness greater than the first thickness T1. The second thickness is not the thickness of the upper support surface 42. As shown in FIG. 4, the second thickness can be a thickness T3 relative to the lower surface 43 of the first support 40-1. The second thickness T2 is the thickness of the lower surface 43. In one embodiment, the second thickness can be the thickness of the first support 40-1 at a partial distance between the upper support surface 42 and the lower surface 43 (e.g., thickness T3). The second thickness can be at least 1.0 mm. In one embodiment, the second thickness can be at least 1.2 mm. This second thickness T2 is sufficient to allow the filter support 34 to be injection molded. For example, it has been found that high injection pressures required to properly injection mold a filter support having a maximum thickness T2 of less than 1.2 mm can result in premature curing of the injected polymer in the injection mold. This premature curing occurs to a significant extent when the maximum thickness T2 is less than 1.0 mm. Therefore, the filter support 34 is advantageously structured so as to be polymer injection moldable.

[0024] The area of ​​the lower surface 43 is larger than the area of ​​the upper support surface 42 on the first support 40-1. The upper support surface 42 on the support 40 is larger than the area of ​​the lower surface 43 on the support 40 (e.g., larger than the area of ​​the lower surface on the same support). In one embodiment, the area of ​​the upper support surface 42 is 85% or less of the area of ​​the lower surface 43 (e.g., 85% or less of the area of ​​the lower surface on the same support). In one embodiment, the area of ​​the upper support surface 42 is 65% or less of the area of ​​the lower surface 43 (e.g., 65% or less of the area of ​​the lower surface 43 on the same support). In one embodiment, the area of ​​the upper support surface 42 is 45% or less of the area of ​​the lower surface 43 (e.g., 45% or less of the area of ​​the lower surface on the same support).

[0025] The first support 40-1 includes a first sidewall 52 and a second sidewall 54. The first sidewall 52 and the second sidewall 54 are disposed opposite each other on the first support 40-1 (e.g., disposed on opposite surfaces of the first support 40-1). For example, in the cross-section of the first support 40-1 shown in FIG. 5, the sidewalls 52, 54 are on opposite surfaces of the first support 40-1. The sidewalls 52, 54 are each a sidewall extending from the upper support surface 42. For example, each sidewall 52, 54 is a sidewall extending between the upper support surface 42 and the lower surface 43. In one embodiment, the interior angle α1 between the upper support surface 42 and the first sidewall 52 is greater than 90° and less than 180°. In one embodiment, the interior angle α2 between the upper support surface 42 and the second side wall 54 is greater than 90° and less than 180°. For example, a 90° interior angle corresponds to a 90-degree angle at which each side wall would extend perpendicular to the upper support surface.

[0026] It should be appreciated that one or more other supports 40 can have similar characteristics as described above with respect to the first support 40-1. In one embodiment, one or more supports 40 have increasing thicknesses as described above with respect to the first support 40-1. For example, the filter support 34, in one embodiment, may have multiple supports 40 having increasing thicknesses as described with respect to the first support 40-1. In such an embodiment, the first thickness of the upper support surface 42 may differ between different supports 40. In one embodiment, at least 50% of the supports 40 in the filter support 34 can each have the characteristics as described above with respect to the first support 40-1.

[0027] The thickness of each of the one or more supports 40 is increased such that the overlap between the upper support surface 42 and the inlet opening 64 in a direction perpendicular to the upper support surface 42 (e.g., in the flow direction D1) is less than 20%. In one embodiment, the overlap between the upper support surface 42 and the inlet opening 64 in a direction perpendicular to the upper support surface 42 is less than 15%. In one embodiment, the overlap between the upper support surface 42 and the inlet opening 64 in a direction perpendicular to the upper support surface 42 is less than 10%.

[0028] Filter support 10 can advantageously allow upper support surface 42 to provide support for an inner portion of filter membrane 32 disposed over inlet opening 64 (e.g., the portion of the filter membrane not sandwiched by outer ring structure 36) and correspondingly occlude only a minimal amount of filter membrane 32 (e.g., less than 20%, less than 15%, less than 10%). The thickness of support 40 (e.g., having a thicker second thickness) can also advantageously allow filter support 34 to be injection molded.

[0029] When purge gas flows through the purge ports 10, backpressure is created as the purge gas flows through the filter membrane 32. Increasing the flow rate of purge gas through the filter membrane 32 also increases the amount of backpressure. The backpressure exerts an upward force on the purge ports 10 and the FOUP 1. If the backpressure becomes high enough, it can lift the FOUP 10 away from the purge nozzles (not shown) that respectively supply purge gas to each purge port 10. The filter support 34 advantageously reduces the backpressure by minimizing the amount of blockage caused by the filter membrane 32, resulting in reduced backpressure. The filter support 34, when used with higher purge gas flow rates, can advantageously achieve reduced backpressure on the purge ports 10. For example, this can allow the FOUP 10 to utilize a higher purge gas flow rate without reaching a greater backpressure that could lift the FOUP 10 away from the purge nozzles.

[0030] 6 is a top view of another embodiment of a filter support 134. The filter support 134 is configured for use in the purge port 10 of the FOUP 1 in a manner similar to the filter support 34 of FIG. 2. The filter support 134 includes an outer ring structure 136 and a support frame 138 extending inwardly from the outer ring structure 136. The support frame 138 includes a plurality of supports 140 and openings 148 extending through the support frame 138 between the supports 140. The filter support 134 can have a configuration similar to that described above with respect to the filter support 34 of FIGS. 2-5, except for the arrangement of the openings 148 and the supports 140 in the support frame 138.

[0031] As shown in FIG. 6 , the supports 140 extend inward from the outer ring structure 136 to a central location 180. For example, the central location 180 can be at the center of the outer ring structure 136. Each support 140 is a rib extending from the outer ring structure 136 to the central location 180. Thus, the filter support 134 does not have a central opening (e.g., central opening 48A). Each of the supports 140 can have characteristics such as those described above with respect to the first support 40-1 of the filter support 34. For example, one or more of the supports 140 have an increasing thickness, as also described above with respect to the first support 40-1 of the filter support 34.

[0032] Aspects Any of the embodiments 1 to 13 can be combined with any of the embodiments 14 to 19.

[0033] Aspect 1. A purge filter support comprising: an outer ring structure; a support frame extending inwardly from the outer ring structure, the support frame including a plurality of supports providing an upper support surface configured to contact and support a filter membrane in a purge port of a front-opening unified pod, the plurality of supports including one or more supports each increasing in thickness from a first thickness of the upper support surface; and one or more openings extending through the support frame between the plurality of supports.

[0034] Embodiment 2. The purge filter of embodiment 1, wherein, for each of the one or more supports, the thickness extends at or generally parallel to the upper support surface.

[0035] Embodiment 3. The purge filter of any one of embodiments 1 and 2, wherein the plurality of supports comprises an inner ring structure disposed within the outer ring structure, and ribs connecting the outer ring structure to the inner ring structure.

[0036] Embodiment 4. The purge filter of embodiment 3, wherein the one or more openings include a central opening extending through the inner ring structure.

[0037] Embodiment 5. The purge filter of any one of embodiments 1-4, wherein each of the one or more supports has a second thickness that is absent from the upper support surface and that is greater than the first thickness.

[0038] Embodiment 6. The purge filter of any one of embodiments 1-5, wherein the plurality of supports includes a first support having a first sidewall extending from an upper support surface, wherein an included angle between the upper support surface and the first sidewall is greater than 90° and less than 180°.

[0039] Embodiment 7. The purge filter of embodiment 6, wherein the first support includes a second sidewall extending from the upper support surface, wherein an included angle between the upper support surface and the second sidewall is greater than 90° and less than 180°, and wherein, in a cross-section of the first support, the first sidewall and the second sidewall are disposed on opposite sides of the first support.

[0040] Embodiment 8. The purge filter of any one of embodiments 1-7, wherein the outer ring structure includes one or more sidewalls that define an inlet opening, and wherein an overlap between the upper support surface and the inlet opening in a direction perpendicular to the upper support surface is less than 20%.

[0041] Embodiment 9. The purge filter of any one of embodiments 1-8, wherein the outer ring structure includes one or more sidewalls that define an inlet opening, and wherein an overlap between the upper support surface and the inlet opening in a direction perpendicular to the upper support surface is less than 10%.

[0042] Embodiment 10. The purge filter of embodiment 8, wherein the overlap between the support frame and the inlet opening in a direction perpendicular to the upper support surface is greater than 20%.

[0043] Aspect 11. The purge filter of any one of Aspects 1 to 10, wherein the support frame has a lower surface formed by a plurality of supports, the lower surface is disposed on the plurality of supports opposite the upper support surface, and the area of ​​the lower surface is larger than the area of ​​the upper support surface.

[0044] Embodiment 12. The purge filter of embodiment 10, wherein the area of ​​the upper support surface is no more than 85% of the area of ​​the lower surface.

[0045] Embodiment 13. The purge filter of any one of embodiments 11 and 12, wherein an area of ​​the upper support surface is no more than 45% of an area of ​​the lower surface.

[0046] Embodiment 14. A front-opening unified pod comprising: a housing; a purge port extending through the housing, the purge port including a filter membrane and a first purge filter support, the first purge filter support including an outer ring structure contacting a periphery of the filter membrane, and a support frame extending inwardly from the outer ring structure and including a plurality of supports providing an upper support surface, the plurality of supports including one or more supports increasing in thickness from a first thickness about the upper support surface; and one or more openings extending through the support frame between the plurality of supports, wherein a flow of purge gas flowing through the purge port is configured to press the filter membrane against the upper support surface of the support frame.

[0047] Embodiment 15. The front-opening unified pod of embodiment 14, wherein the purge port includes a second purge filter support including a second outer ring structure and a second support frame extending inwardly from the second outer ring structure, the second support frame including a plurality of second supports providing a second support surface that contacts and supports the filter membrane, the filter membrane being disposed between the upper support surface of the first purge filter and the second support surface of the second purge filter support.

[0048] Embodiment 16. The front-opening unified pod of embodiment 15, wherein a peripheral edge of the filter membrane is sandwiched between an outer ring structure of the first purge filter support and a second outer ring structure of the second purge filter support.

[0049] Embodiment 17. The front-opening unitary pod of any one of embodiments 14-16, wherein the purge port includes a check valve.

[0050] Embodiment 18. The front-opening unified pod of any one of embodiments 14-17, wherein the outer ring structure includes one or more side walls defining an inlet opening, wherein the purge gas is configured to flow in a first direction through the purge filter support, and wherein an overlap between the upper support surface and the inlet opening in the first direction is less than 10%.

[0051] Embodiment 19. The front-opening unified pod of embodiment 18, wherein the overlap between the support frame and the entrance opening in the first direction is greater than 20%.

[0052] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalents of the claims are intended to be embraced.

Claims

1. A purge filter support configured to be included in a purge filter including a filter membrane, comprising: an outer ring structure; a support frame extending inwardly from the outer ring structure, the support frame including a plurality of supports providing an upper support surface configured to contact and support the filter membrane within a purge port of a front-opening unified pod, the plurality of supports including one or more supports each increasing in thickness from a respective first thickness of the upper support surface; one or more openings extending through the support frame and between the plurality of supports; Equipped with A purge filter support configured such that the purge filter is supported in place within the purge port by upper and lower retaining members.

2. The plurality of supports are an inner ring structure disposed within the outer ring structure; a rib connecting the outer ring structure to the inner ring structure; 10. The purge filter support of claim 1, comprising:

3. A forward-opening unified pod, Housing and a purge port extending through the housing; and Equipped with The purge port is an upper holding member and a lower holding portion; A purge filter, A filter membrane; a purge filter including a first purge filter support; Including, The first purge filter support comprises: an outer ring structure contacting a periphery of the filter membrane; a support frame extending inwardly from the outer ring structure, the support frame including a plurality of supports providing an upper support surface, the plurality of supports including one or more supports each increasing in thickness from a respective first thickness relative to the upper support surface; one or more openings extending through the support frame between the plurality of supports; a flow of purge gas through the purge port configured to press the filter membrane against the upper support surface of the support frame; the purge filter is configured to be held in place within the purge port by upper and lower retaining members; Forward-opening unified pod.

4. the purge filter includes a second purge filter support including a second outer ring structure and a second support frame extending inwardly from the second outer ring structure, the second support frame including a plurality of second supports providing a second support surface that contacts and supports the filter membrane; the filter membrane is disposed between the upper support surface of the first purge filter support and the second support surface of the second purge filter support. The forward-opening unified pod according to claim 3 .

5. the outer ring structure includes one or more sidewalls defining an inlet opening; the purge gas is configured to flow in a first direction through the first purge filter support; an overlap between the upper support surface and the inlet opening in the first direction being less than 10%; The forward-opening unified pod according to claim 3 .

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