TWM552185U - Gasket for sealing a substrate container and substrate container using the same - Google Patents

Abstract

A gasket and substrate container with improved conductance. In one embodiment, the gasket provides two lines of sealing contact. A flange portion of the gasket provides a first line of sealing contact and provides a firm but semi-rigid interface with the soft gasket material, which may also act as a compressed stop between a door and a shell of the substrate container. A second line of sealing may also be provided by a flexible tip structure that extends radially outward and in a forward direction from the flange portion. The dual seal has been shown to reduce leak rates by three- to four- fold over conventional substrate containers.

Description

Pad for sealing a substrate container and substrate container using the same

This creation is generally directed to substrate containers and wafer carriers, and more particularly to door seals for such substrate containers.

Various conventional substrate carriers, such as a front open unit (FOUP) and a standard mechanical interface (SMIF), include a container shell defining an opening for access. The opening of the shell is typically surrounded by a frame that houses the door and the door is latched into the frame to form a casing with the shell. Elastomeric seals, also known as gaskets, are placed between the door and the shell to attempt to maintain the integrity of the microenvironment within the enclosure.

Some conventional substrate containers substantially prevent particles from entering the interior of the enclosure during cleaning and provide some degree of low pressure sealing. However, conventional substrate containers are not sufficient to maintain a low pressure seal for a long time. For many conventional substrate containers, the internal pressure of the container is balanced with the surrounding environment within a few minutes. Container leaks, also known as "conduction", are problematic. The entry of gases, especially oxygen (air) into the substrate container, poses a problem for wafer fabrication. Oxygen may form oxides on the surface, forming defects, and reducing overall yield and overall degrading the substrate.

Therefore, it is desirable to prevent such components from entering the microenvironment within the enclosure.

Various embodiments of the present work include an improved sealed liner for a substrate container. The disclosed seal is used to limit the position of the door in a direction parallel to the mounting axis of the door. Sealing table The face acts as a compressible stop that is aligned against the door during installation. The compressible stop is configured to interfere with the shell sealing surface before the door is fully engaged, thus forming a seal along the perimeter. In some embodiments, the seal includes a second feature that provides additional interference with the surface of the shell, thereby conforming to the contour of the surface of the shell and permitting some minor misalignment and minor variations in the shell sealing surface.

By combining these features, various embodiments of the present invention use two methods to form a seal. One method is a large compression surface and the second method is a flexible tip structure. In this manner, some embodiments provide two seals with the same liner. The large compression surface forms a primary seal. The wide flange portion of the pad enables adjustment as the door moves over a large amount within the shell. The flexible tip structure incorporates a primary seal of the flange portion to form a very low pressure seal. Bridging to the top end of the flange portion with a cantilever or flexure provides positive deflection in the direction of the seal to provide a positive seal feature.

Therefore, the seal is maintained at a low pressure, and it is generally difficult to maintain a seal at a low pressure. This tip additionally allows for erroneous adjustments in the interface between the shell and the door while still forming a seal.

10‧‧‧ cushion

20‧‧‧Substrate container

24‧‧‧

26‧‧‧ Shell

32‧‧‧Flange section

36‧‧‧ positive

38‧‧‧Back

40‧‧‧Flange thickness

50‧‧‧Flexible top structure

52‧‧‧Crimping section

54‧‧‧Flexed part

56‧‧‧Flex thickness

60‧‧‧ anchoring section

62‧‧‧radial protruding ribs

66‧‧‧ Anchoring recess

68‧‧‧ deflection recess

72‧‧‧Seal interface interface

74‧‧‧First sealed contact line

76‧‧‧Second sealing contact line

n‧‧‧Backward direction

X‧‧‧ forward direction

Y‧‧‧pad axis

1 is a perspective view of a pad in accordance with an embodiment of the present invention.

2 is a substrate container of the liner of FIG. 1 implemented in accordance with an embodiment of the present invention.

3 is a cross-sectional view of the gasket of FIG. 1 in accordance with an embodiment of the present invention.

4 is a partial cross-sectional view of the door of the shell of FIG. 2 in accordance with an embodiment of the present invention.

Figure 5 is a partial cross-sectional view of the door and shell of Figure 2 joined to the gasket of Figure 1 in accordance with an embodiment of the present invention.

Figure 6 is a graph comparing the oxygen concentration of a conventional substrate container with a substrate container having an "ideal" seal with the substrate carrier of Figure 2 in accordance with an embodiment of the present invention.

Referring to Figure 1, a liner 10 in accordance with an embodiment of the present invention is depicted. The liner 41 is continuous about the liner axis y . An r-θ-z coordinate system is depicted, the z-axis being concentric with the pad axis y .

Referring to Fig. 2, a substrate container 20 for implementing the liner 10 of Fig. 1 in accordance with an embodiment of the present invention is depicted. The substrate container 20 includes a door 24 and a shell layer 26. In some embodiments, the gasket 10 is mounted to the door 24 of the substrate container 20, as depicted in FIG. In other embodiments, the liner 10 is mounted to a shell 26 (not depicted).

Referring to Figure 3, a cross-sectional view of the liner 10 of Figure 1 in accordance with an embodiment of the present teachings is depicted. The liner 10 includes a flange portion 32 that is continuous about the liner axis, and the flange portion 32 includes a front side 36 and a back side 38. A flange thickness 40 is defined between the front face 36 and the back face 38, the flange thickness 40 being defined as the dimension between the front face 36 and the back face 38 that is parallel to the pad axis y . The front side 36 faces in a direction x parallel to the pad axis y .

In various embodiments, the flexible tip structure 50 extends radially outward from the flange portion 32. The flexible tip structure 50 includes a beaded portion 521 and a flex portion 54. The curled portion 52 extends forwardly from the front side 36 of the flange portion 32 in the forward direction. The flex portion 54 bridges the flange portion 32 and the bead portion 52. The flex portion 54 includes a flex thickness 56 that is defined as an axial thickness parallel to the pad axis y . The flex thickness 56 is less than the flange thickness 40 of the flange portion 32. In various embodiments, the flexible tip structure 50 and the flange portion 32 are integrally formed with each other to form a single unitary piece.

In various embodiments, the liner 10 includes an anchor portion 60 that extends from a flange portion 32 adjacent the back surface 38 in a rearward direction parallel to the liner axis, the rearward direction being opposite the forward direction. In some embodiments, the anchor portion 60 includes a radially protruding rib 62. The radially projecting ribs 62 can extend radially inward from the anchor portion 60 (as shown) or radially outward from the anchor portion 60. In some embodiments, the flange portion 32, the flexible tip structure 50, and the anchor portion 60 are This integrally forms a single, unitary part.

Referring to Figures 4 and 5, the liner 10 is depicted in the operation of one embodiment of the present creation. The shell 26 defines an opening and the door 24 is mounted within the opening. The gasket 10 is disposed between the shell 26 and the door 24 and provides a sealing contact between the shell 26 and the door 24. In the depicted embodiment, the door 24 defines an anchoring recess 66 in which the anchor portion 60 of the cushion 10 is disposed. Also in the depicted embodiment, the door 24 defines a deflection recess 68 that is continuous and axially aligned with the back surface 38 of the flexible tip structure 50. The deflecting recess 68 is sized such that the flexible tip structure 50 can deflect therein to prevent the flexible tip structure 50 from compressing between the door 24 and the shell 26.

In the depicted embodiment, the shell layer 26 includes a sealing interface portion 72 that contacts the flange portion 32 of the gasket 10 to define a first sealing contact line 74 between the flange portion 32 and the sealing interface portion 72 (Fig. 5) . In various embodiments, the sealing interface portion 72 contacts the beaded portion 52 of the flexible tip structure 50 to define a second sealing contact line 76 between the beaded portion 52 and the sealing interface portion 72.

Functionally, compression of the flange portion 32 along the first sealing contact line 74 provides a strong but semi-rigid interface with the soft gasket material and a compression stop for the shell. When the liner 10 is compressed during closure, it forms a sealing lip on the periphery. The flexible tip structure 50 provides contact along the second sealing contact line 76 proximate the perimeter of the seal. The crimped portion 52 follows the geometry and curvature of the sealing interface surface. Any undulations in the surface profile will be compensated for by the flexible tip structure 50.

The deflecting recess 68 enables the flexible tip structure 50 to deflect in the rearward direction n without being sandwiched between the door 24 and the shell 26. This reduces the deformation or wrinkling of the seal because the seal can slide freely over the sealing interface portion and find a naturally balanced configuration. Two seal lines are formed between the gasket 10 and the sealing interface portion 72.

Referring to FIG. 6, a substrate container and a conventional base for comparing the creations are described for an embodiment of the present creation. Experimental data for plate containers and "ideal" seal configurations. The graph of Figure 6 depicts the oxygen concentration in the purge carrier versus the time the vessel was purged. In this example, the conventional substrate container is a standard A300 wafer carrier. The "ideal" seal is an A300 carrier that has been specifically sealed so that there is no leakage through the door; instead, leakage occurs through other paths, such as purging the crucible. Therefore, the "ideal" seal represents the basis on which the liner can be achieved.

The "Paneled Door" data indicates the A300 with the padding of this creation. Presenting two data sets - implementing a first or upper data set with a door with a plastic latch configuration, implementing a second or lower data set with a metal latched configuration door. In both instances, the improvement in the seal, as indicated by the time it takes to reach a given oxygen concentration, is significantly improved. For example, conventional substrate containers achieve an oxygen content of 200 parts per million (ppm) in less than 30 minutes, while a door with a disclosed pad reaches the same 200 ppm after 90 minutes or even 120 minutes. Oxygen content. This represents a three to four times better leak rate for containers that implement the disclosed liners than conventional substrate containers.

10‧‧‧ cushion

X‧‧‧ forward direction

Y‧‧‧pad axis

Claims (11)

A pad for sealing a substrate container, the pad comprising: a flange portion continuous about a pad axis, the flange portion including a front surface and a back surface, and defining the front surface and the back surface a first axial thickness parallel to one of the pad axes, the front face being oriented in a forward direction parallel to one of the pad axes; a flexible tip structure extending radially outward from the flange portion The flexible tip structure includes a bead portion and a flex portion extending forwardly from the front surface of the flange portion in the forward direction, the flex portion bridging the flange portion and The beaded portion defines a second axial thickness parallel to one of the pad axes, the second axial thickness being less than the first axial thickness of the flange portion. The pad of claim 1, wherein the flange portion and the flexible tip structure are unitary. A pad of claim 1, comprising an anchor portion extending from a flange portion adjacent to the back surface in a rearward direction parallel to the pad axis, the rearward direction and the The forward direction is opposite. A pad of claim 3, wherein the flange portion, the flexible tip structure, and the anchor portion are integral. A pad of claim 3, wherein the anchoring portion comprises a radially protruding rib. A pad of claim 5, wherein the radially projecting ribs extend radially inward from the anchoring portion. A substrate container comprising a shell defining an opening, a door mounted within the opening, and a request item disposed between the shell and the door and providing a sealed contact between the shell and the door A liner of any of 1 to 2. A substrate container comprising a shell defining an opening, a door mounted within the opening, and a request item disposed between the shell and the door and providing a sealed contact between the shell and the door A liner of any of 3 to 6. The substrate container of claim 8, wherein the door defines an anchoring recess in which the anchoring portion of the cushion is disposed. The substrate container of claim 9, wherein the door defines a deflecting recess that is continuous and axially aligned with a back surface of the flexible tip structure, the deflecting recess being sized to provide the flexibility The tip structure can be deflected therein to prevent compression of the flexible tip structure between the door and the shell. The substrate container of claim 10, wherein the shell layer includes a sealing interface portion that contacts the flange portion of the gasket to define a first sealing contact between the flange portion and the sealing interface portion A wire, the sealing interface portion contacting the bead portion of the flexible tip structure to define a second sealing contact line between the bead portion and the sealing interface portion.