JP4896007B2 - Wafer container with sealable door - Google Patents

Description

(Related application)
This application claims the benefit of US Provisional Patent Application No. 60/563529, entitled “WAFER CONTAINER WITH SEALABLE DOOR”, filed April 18, 2004, the entirety of which is incorporated herein by reference. Is done.

  The present invention relates to containers, and more particularly to sealable doors for semiconductor wafers.

  Semiconductor wafers have undergone numerous treatments during processing. This usually involves transporting multiple wafers between workstations or equipment for processing. Semiconductor wafers are easily scratched and easily damaged by physical contact or shock and static electricity. Furthermore, semiconductor manufacturing processes are extremely sensitive to contamination by particles or chemicals. Therefore, in order to reduce the adverse effects of wafer contaminants, special containers have been developed to minimize common contaminants and to isolate the wafer from contaminants outside the container. These containers generally include a removable door with a gasket or other device to provide a tight seal of the door to the container body.

  As semiconductors are getting smaller in scale, i.e., the number of circuits per unit area is increasing, particulate contamination is much more problematic than before. The size of the particles that can break the circuit is decreasing and approaching the molecular level. Thus, greater particle control is desired at all stages of semiconductor wafer manufacturing, processing, transport, and storage.

  Wafer carriers are generally made from thermoplastic materials. For example, the initial container disclosed in US Pat. No. 4,248,346 was made of a highly moldable plastic such as polyethylene. Recent containers are supported by a rigid h-bar, molded into an elongated small hole, as disclosed in US Pat. No. 5,273,159, and are flexible, for example, as disclosed in US Pat. No. 5,586,658. Sometimes made of polycarbonate with a more elastic covering. Each of U.S. Pat. Nos. 4,248,346 and 5,586,658 is hereby fully incorporated by reference.

  Some conventional containers have a door seal to the enclosure and can also be sealed to the processing equipment. Such containers are referred to as “SMIF pods” (Standard Mechanical Interface) in which the door closes the lower open part of the container part, or FOUPs (Front Opening Unified Pods) and FOSBs (Front Opening Shipping Box) in which the door closes the open front part. It was. These containers have very strict structural and performance requirements. For example, they must be mechanically sealed and locked by both robotic means and manual means, and must be hermetically sealed by simply closing the door and locking it in place with respect to the container. .

  Conventional seals for both SMIF pods and transport modules are generally relatively simple elastic seals that are simply compressed axially between the door and the enclosure to provide a seal. Such seals tend to over-press, particularly when the polycarbonate material is in contact with an elastic seal, resulting in uneven openings, reduced average life of the seal, and poor sealing.

A very recent design features a seal cross-section characterized by a bridge extending radially outward relative to the vertical end, with a knife edge in contact with the bridge in addition to axial compression of the end. Giving a seal. An example of such a design is found in US patent application Ser. No. 09/998621, named “SEALING ELEMENT, HERMETIC CONTAINER AND SEALING METHERED THEREOF” by Takahashi et al., Which is hereby fully incorporated by reference. The problem with this approach, however, is the “divergent column buckling” at the end, where the free end of the end buckles radially inward over one tangential part of the seal and in the other tangential part Buckling outward. Such a scenario allows the seal to leak at the transition point between inner and outer buckling.
U.S. Pat. No. 4,248,346 US Pat. No. 5,273,159 US Pat. No. 5,586,658 US Patent Publication No. 2002/0195455

  What is needed in the industry is a better performing and longer lasting sealing structure for sealing the door to the enclosure of the wafer container.

SUMMARY OF THE INVENTION The present invention addresses industry demands for better performing and longer lasting seal structures for wafer containers by providing an elastic seal that does not rely on direct compression when sealing. To do. In accordance with the present invention, a wafer container includes an enclosure with a door frame that defines an opening for insertion and removal of the wafer and a door that can be attached to the door frame to seal the enclosure. In an embodiment of the present invention, a continuous elastic seal extends around the door inside the periphery. The seal can be partially inserted into the radial configuration of the door, located on the sealing surface adjacent to the periphery of the door. In cross section, the elastic seal has an insertion portion, a bridging portion connected to the insertion shaft and extending radially outward with respect to the door axis, and a seal head portion connected to the bridging portion. The seal head portion includes a foot portion that protrudes from the bridge portion toward the seal surface of the door, and a head portion that extends in a direction substantially opposite to the foot portion with respect to the bridge portion. Since the door frame has a seal engagement structure such as a rib extending around the door frame, when the door is seated on the door frame, the bridging portion of the elastic seal comes into contact with the seal engagement structure. In the seal engagement structure, the bridging portion is displaced in the axial direction toward the seal surface, and the head portion of the seal head is rotated in the radial direction to come into contact with the seal engagement structure. This displacement action also positively positions the foot of the seal head in contact with the sealing surface of the door frame.

  As another example, when seated, the frame can be dimensioned such that the bridging portion of the elastic seal is intervened and compressed between the door sealing surface and the door frame sealing surface.

  An advantage of the present invention is that a double seal is made on each side of the elastic seal. For door frame and seal contact surface, seal line contact between the projecting part of the frame and the bridging part of the seal, and contact of the seal line between the head part of the seal end and the tangential periphery of the projecting part of the frame There is. For the contact surface between the seal and the door sealing surface, the seal line contact between the seal head foot and the door sealing surface, and between the outer corner of the insert and the door sealing surface. There is a seal line contact.

  Another advantage is that the rotational action does not cause axial compression of the seal end, thus eliminating the possibility of diverging column buckling. Rather, the sealing action of the seal end is accomplished by a predictable and repeatable rotation of the seal end end. Further, since the contact force between the seal and the surface is reduced, there is no compression of the seal end and the pressing is reduced.

  Furthermore, an advantage of the preferred embodiment of the present invention is that it can be easily replaced when the seal wears out or when another sealing characteristic is desired.

Detailed Description of the Preferred Embodiment Referring to FIGS . 1-2, a wafer container 20 commonly known as a transfer module includes an enclosure 22 and a door 24 as a concept. The enclosure 22 generally includes a shell 26 that defines an interior space 28 to enclose a plurality of wafers 30. The shell 26 has a pair of opposing side walls 32, 34, an upper part 36, a lower part 38, and a back part 40. The open front 42 faces the back 40 and is defined by a door frame 44 that receives the door 24 for sealingly enclosing the interior space 28. It should be noted that the “door frame” as used herein is not limited to a structure separate from the enclosure 22 or an additional structure, that is, a structure integrated with the enclosure 22. Should. If anything, a “door frame” is defined as being just part of the portion of the enclosure 22 that receives the door 24. The enclosure 22 may also include a robot lifting flange 46 on the upper portion 36, a manual handle 48 on the side walls 32, 34, and a kinematic coupling having a groove 49 on the outer surface of the lower portion 38.

  The door 24 generally includes an outer frame portion 50 and an outer panel 52, and has an inner surface 54 and an outer surface 56. The door 24 is given an axis annotated in the figure as “A1”, and the closing part is given an axis annotated in the figure as “A2”. For proper insertion of the door 24 into the door frame 44, the axes A1 and A2 should be axially aligned. When the door 24 is inserted into the door frame 44, the door 24 moves in the axial direction. When “radial” is used herein, it refers to a direction or orientation perpendicular to the axis A1 or A2.

  The door seal surface 58 extends around a portion of the door inner surface 54 adjacent to the periphery 60 of the door 24. The door 24 generally has one or more locking mechanisms 62 for the outer frame 50 that can be operated through the keyhole 63 to securely lock the door 24 to the door frame 44. The locking mechanism 62 is a David. L. It can be operated as disclosed in US Pat. No. 5,711,427, attached to David L. Nyeth and owned by the owner of the present invention, which is hereby incorporated by reference in its entirety. The door 24 may further include a door guide 64 at each corner 66 to accurately position and position the door 24 within the door frame 44. A wafer cushion 68 having an elastic finger 70 for engaging with one of the plurality of wafers 30 may be provided on the inner surface 54 of the door 24.

  Another embodiment of a wafer container 20 known as a SMIF (Standard Mechanical Interface) pod is shown in FIGS. In this embodiment, the wafer container 20 also generally includes an enclosure 22 and a door 24. The enclosure 22 generally includes side walls 72, 74, 76, 78 and an upper portion 80 that is opposite the open bottom 82. Similar to the open front of the embodiment of FIGS. 1-2, the open bottom 82 is defined by a door frame 44 that receives a door 24 for sealingly enclosing the interior space 28.

  The door 24 in the embodiment of FIGS. 3-8 includes an outer frame 50 and has an inner surface 54 and an outer surface 56. Again, the door seal surface 58 extends around a portion of the door inner surface 54 adjacent to the periphery 60 of the door 24. The door 24 generally has one or more locking mechanisms 62 on the outer frame 50 to securely lock the door 24 to the door frame 44. The door 24 may further have a door guide 64 at each corner 66 to accurately position and position the door 24 of the door frame 44. A wafer support structure 84 comprising a plurality of wafer receiving shelves 86 is engaged with a structure 88 on the inner surface 54 of the door 24.

  FIG. 4 shows a cross-sectional view of the door 24 in the vicinity of the periphery 60. The door seal surface 58 is bounded by the peripheral edge 90 of the door 24 and the insertion radial groove 90. The elastic seal 94 extends on the seal engagement surface 58 around the periphery 90 and inward, and has a pair of opposed edges 95 and 95a. The elastic seal 94 generally includes a mounting portion 96 that extends along the inner edge 95 and a seal head portion 97 that extends along the outer edge 95a. The elastic seal 94 has a larger dimension ΔR in the radial direction and a smaller dimension ΔZ in the axial direction. The bridging portion 98 extends between the attachment portion 96 and the seal head portion 97 and generally includes an adjacent portion 100 connected to the attachment portion 96 and an intermediate portion 102 connected to the seal head 97. The seal head 97 generally includes a head portion 106 that extends axially away from the door seal surface 58 and a foot portion 108 that extends toward and faces the door seal surface 58. The bridge 98 and the seal head 97 generally have a t-shaped cross section in this embodiment. The attachment 96 of the elastic seal 94 is received in the insertion radial groove 92 of the door 24 as shown.

  Referring now to the cross-sectional view of FIG. 6, the door 24 is engaged with the door frame 44. In the illustrated embodiment, the door frame 44 is integral with the enclosure 22 and extends generally around the perimeter structure 110 and the periphery of the door frame and into a recess 114 defined by the outer flange wall 116. And a seal engaging protrusion 112 in the form of a general rib. A frame seal surface 118 is provided on the seal engagement protrusion 112. The separation structure 110 engages with the door inner surface 54, and thereby arranges the frame seal surface 118 in the axial direction with respect to the door 24 to determine the depth of engagement of the door frame 44 with the door 24. It will be apparent that the spacing structure 110 can be appropriately sized or shimmed to control the contact force between the elastic seal 94 and the seal engagement protrusion 112.

  Importantly, the elastic seal 94 is substantially uncompressed when the door 24 engages the door frame 44, and the seal engagement protrusion 112 rather deflects the bridge 98 of the elastic seal 94. . This engagement results in four separate seal lines of contact between the resilient seal 94, the enclosure 22, and the door 24. The head portion 106 of the seal head 97 bends radially inward to contact the tangential periphery 120 of the seal engagement protrusion 112 and form a first line contact 122. A second line contact 124 is formed between the intermediate portion 102 of the bridging portion 98 and the frame seal surface 118. A third line contact 126 is formed between the foot 108 of the seal end 97 and the door seal surface 58. Finally, a fourth line of contact 128 is formed between the corner 130 of the attachment 96 and the door seal surface 58.

  Another embodiment of the present invention is shown in FIG. In this embodiment, the door frame 44 is substantially the same except that the engagement protrusion 112 has a rounded knife edge engagement portion 132. A second line contact 124 is thus formed between the protrusion 134 of the rounded knife edge engaging portion 132 and the intermediate portion 102 of the bridging portion 98, with the other tangent lines contacting at the same position as before. .

  In one embodiment, the elastic seal 94 may feature a plurality of protrusions 134 and is shown in the cross-sectional view of FIG. The protrusions 134 protrude from the attachment part 96 at a predetermined interval. The protrusion 134 fits into a through groove 136 formed in a radially extending lip 138 adjacent to the insertion radial groove 92, and fixes the elastic seal 94 to the insertion radial groove 92. As shown in FIG. 3, the number and position of the through grooves 136 and the protrusions 134 are asymmetric with respect to adjacent portions and can provide an indexing attachment of the elastic seal 94.

  Various other preferred embodiments of the elastic seal 94 in accordance with the present invention are shown in FIGS. 9-14, wherein the engagement protrusions 134 are engaged and deflected in a free state for various shapes. Both are shown with imaginary lines.

1 is a perspective view of an embodiment of a front insertion type wafer container according to the present invention. FIG. FIG. 2 is an internal view of the wafer container door of FIG. 1. 1 is a top perspective view of an embodiment of a lower insertion wafer carrier according to the present invention. FIG. FIG. 3 is a cross-sectional view of an embodiment of an elastic seal according to the present invention disposed on a wafer container door. FIG. 6 is a cross-sectional view of another embodiment of an elastic seal according to the present invention. FIG. 3 is a cross-sectional view of an elastic seal according to the present invention showing the engagement of the seal between the door and the door frame of the wafer container. FIG. 4 is a cross-sectional view of an elastic seal according to another embodiment of the present invention showing the engagement of the seal between the door and the door frame of the wafer container. FIG. 4 is a lower perspective view of the lower insertion type wafer carrier of FIG. 3. It is sectional drawing of another embodiment of the wafer carrier of this invention, Comprising: It is a figure which shows an elastic seal and a seal engaging part in the state which does not bend, and the state which bent. FIG. 6 is a cross-sectional view of another embodiment of the wafer carrier of the present invention, showing the elastic seal and the seal engaging portion in an undeflected state and a deflected state. FIG. 6 is a cross-sectional view of yet another embodiment of the wafer carrier of the present invention, showing the elastic seal and the seal engagement portion in an undeflected state and a deflected state. FIG. 6 is a cross-sectional view of yet another embodiment of the wafer carrier of the present invention, showing the elastic seal and the seal engagement portion in an undeflected state and a deflected state. FIG. 6 is a cross-sectional view of yet another embodiment of the wafer carrier of the present invention, showing the elastic seal and the seal engagement portion in an undeflected state and a deflected state.

Claims (6)

A sealable container for holding a plurality of wafers,
An enclosure defining an interior space for receiving the wafer;
A door that can be attached to a door frame in order to seal and close the open side of the enclosure, the door having an inner side and providing a door periphery;
An elastic seal arranged on the inner side of the door around and inward of the door periphery;
Have
The enveloping part is provided with an open side defined by a door frame, comprising a sealing engagement member projecting outwardly from the door frame is arranged around the a and the frame peripheral frame periphery Rutotomoni the door frame The seal engaging member is configured as a continuous rib having a tip portion, an inwardly facing surface, and an outwardly facing surface;
The elastic seal has an inner end portion and an outer end portion, a seal head structure extending along the outer end portion, and a bridging portion, and the inner end portion extends along the end portion. And has an attachment structure for attaching to the groove of the door, and the bridge portion connects the attachment structure and the seal head structure,
The bridging portion and the seal head structure define a t-shaped portion having an arm that contacts the door and an opposing arm that extends outward from the inner side of the door;
The sealing engagement member and the elastic seal is arranged to cooperate, when the door engages the door frame, the tip portion of the sealing engagement member, first contacts the bridge portion of the elastic seal, door Establishing contact of the first seal line along the periphery and pulling the arm facing the door of the t-shaped portion inwardly toward the mounting structure by engagement with the bridging portion, thereby The arm engages with the outwardly facing surface of the engagement member to establish contact of the second seal line along the door periphery , and the seal head structure contacts the door and a third along the door periphery. A container that establishes seal line contact. The container according to claim 1, wherein the mounting structure contacts the door and establishes contact of a fourth seal line along the door periphery . The container according to claim 1, further comprising a separation structure in the enclosure to provide an engagement depth for the door when the door is attached to the door frame . The container of claim 1, wherein the attachment structure has a plurality of protrusions, and the door has a plurality of structures for receiving the protrusions to hold an elastic seal against the door . The container of claim 1, further comprising at least one locking mechanism operably associated with the door to lock the door in place within the door frame . The container according to claim 1, wherein the seal engaging member has a knife edge engaging portion .

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