Patent Application
20060000747
1. Field of the Invention
This invention relates to a container for shipping a stacked array of integrated circuit wafers such as semiconductor wafers. More particularly, the present invention relates to horizontal-type wafer shipping containers that may be reused a number of times.
2. Description of the Related Art
A variety of shipping containers are known for shipping and storing integrated circuit wafers. Typically, these containers are intended to provide a stable support for shipping and handling a number of wafers simultaneously. The containers are also intended to provide sufficient protection to substantially reduce the likelihood of breakage of the wafers, which are typically brittle. It is also desirable for wafer shipping containers to protect the wafers from contamination from airborne particulates and an excessive accumulation of static electricity.
Two general types of reusable shipping containers are in common use for shipping integrated circuit wafers. One type of shipping container has a chamber with internal structure for retaining an array of disc-shaped wafers in an aligned row. This type of shipping container is known as a “vertical shipper” or “front opening shipping box”. The other type of shipping container is known as a “HWS” or “horizontal wafer shipper” and has a chamber for retaining a plurality of wafers in a stacked array, with separators between the wafers and foam cushions placed above and below the stacked array for cushioning.
Shipping containers for integrated circuit wafers are often constructed to be used in conjunction with automated equipment that unloads each wafer from the container when needed for use. For example, some front opening shipping boxes have a bottom surface that is adapted to be releasably received onto a “load port” in a manufacturing assembly line. The load port typically has a clamp, such as an “L”-shaped pin or a “T”-shaped pin, that pivots to engage an overhang or other structure attached to the bottom of the container in order to retain the container in place. Once the shipping container is clamped onto the load port, a robot arm or other automated device removes the wafers from the shipping container in sequential fashion.
In many instances, the bottom sections of wafer shipping containers are provided with a series of cavities that are precisely positioned in a standardized, predetermined arrangement. These cavities are known as “information pad holes” or “info pad holes” and often comprise four circular cavities or recesses that are arranged in a generally “V”-shaped pattern. Some or all of the cavities are then filled with snap-in plastic plugs according to a pre-defined set of rules that provide information relating to the identity or use of the wafers in that container. In particular, the user may select certain cavities to be filled by plugs in order to provide information such as the type of wafers in the container, or a desired location where the wafers are to be used in a particular manufacturing line.
As an example, a shipping container with four info pad holes may be provided with one plug that fills a certain one of the four holes. In turn, the desired load port is arranged with three projections for reception in the unfilled cavities. If, for example, the three projections correspond to the arrangement of the three unfilled cavities, the shipping container will rest flatly against the upper surface of the load port. On the other hand, if the shipping container cannot be flatly received on the load port due to contact of projections against plugs mounted in one of the three cavities, the user is thereby tacitly informed that the selected shipping container is not the proper container for use at that particular load port.
While the horizontal wafer shipping containers described above have been deemed satisfactory by many, there is a continuing need to improve the state of the art with respect to such containers. In particular, features that provide additional protection for the wafers and facilitate use of the shipping container are especially desirable.
The present invention relates to a horizontal wafer shipping container that is constructed to provide enhanced protection against contaminates for integrated circuit wafers received in the container. The container includes an upper section with a continuous depending wall having a lower edge portion, and a lower section in contact with a seal. The seal contacts the lower edge portion when the lower section and the upper section are assembled together.
The present invention also relates to a shipping container for integrated circuit wafers, wherein a lower section of the container includes a plurality of cavities that receive info pad plugs. At least one of the info pad plugs includes an adhesive for connecting the plug to the lower section.
In more detail, the present invention is directed in one aspect to a shipping container for integrated circuit wafers. The shipping container comprises a lower section including a base and a wall extending upwardly from the base. The base and the wall of the lower section define a chamber for receiving a plurality of integrated circuit wafers. The base includes a shoulder that extends next to the wall of the lower section along a path that lies in a flat reference plane. The shipping container also comprises an upper section including a top and a wall depending from the top. The wall of the upper section extends continuously along a path that is adjacent the periphery of the top and has a lower edge portion. The lower edge portion extends along a path that lies in a flat reference plane and is adjacent the shoulder when the lower section and the upper section are assembled together. The shipping container also includes a seal that is in contact with the lower edge portion and the shoulder when the lower section and the upper section are assembled together.
The present invention is also directed in another aspect to a shipping container for integrated circuit wafers. The container comprises an upper section including a top and a wall depending from the top. The shipping container also comprises a lower section releasably connected to the upper section. The lower section includes a base and a wall extending upwardly from the base. The base and the wall of the lower section define a chamber for receiving a plurality of integrated circuit wafers. The lower section additionally includes a plurality of cavities for receiving info pad plugs. The shipping container also comprises at least one info pad plug received in one of the cavities. At least one info pad plug comprises a body and an adhesive for connecting the body to the lower section.
These and other aspects are described in more detail in the description that follows and are illustrated in the accompanying drawings.
A shipping container for integrated circuit wafers according to one embodiment of the present invention is illustrated in
In more detail, the lower section 12 includes a base 16 having an overall, generally octagonal configuration in plan view as shown in
The lower section 12 also includes a wall 18 that extends upwardly from the base 16. As depicted in
The base 16 includes a shoulder 21 that is located radially outwardly from the wall 18. A groove 24 is disposed on the shoulder 24 and extends along a circular path that is concentric with the path of the wall 18.
A seal 26 is received in the groove 24. The seal 26 extends along a circular path in a flat reference plane parallel to the plane of extension of the base 16. The seal 26 may comprise an O-ring made of, for example, silicone rubber or other elastomeric materials. Alternatively, the seal 26 may be constructed of other gasket materials such as a resilient polymeric foam having a durometer in the range of about 10 A to about 60 A, and more preferably about 30 A. The use of foam materials is presently preferred because such materials are reduced in volume when compressed, in contrast to other materials that are displaced when compressed. However, other materials may also be used, including a molded polymer with a thermally activated foaming agent, a gel (preferably a UV-curable crosslinkable gel), a tacky adhesive or a hollow tube.
The seal 26 has sufficient memory to recover its original shape when relaxed, and yet is sufficiently flexible to ensure that the seal 26 conforms to the shape of the groove 24 when compressed. The seal 26 as shown in the drawings has a circular cross-sectional configuration, although other cross-sectional configurations (such as rectangular, square or wedge-shaped) are possible as well. Preferably, the cross-sectional configuration of the seal 26 matches the cross-sectional configuration of the groove 24. For example, in the exemplified embodiment shown in the drawings (see, e.g.,
The upper section 14 includes a top 28 having a flat configuration. Optionally, the top 28 includes a locater or index mark 29 (
The wall 30 includes a lower edge portion 32 that extends along a path lying in a flat reference plane. The lower edge portion includes a pair of ribs 22, each of which extends along a circular path that is concentric with the inner surface of the wall 30. When the upper section 14 and the lower section 12 are assembled together as shown in
The construction of the container 10 with respect to the shoulder 21, the seal 26 and the ribs 22 is a particular advantage, in that the seal 26 contacts the ribs 22 and the groove 24 in flat, parallel reference planes. Certain prior art horizontal wafer shipping containers, such as shipping containers similar to the container described in U.S. Pat. No. 6,193,090, were provided with a gasket or seal that extended along an undulating path including portions following along the periphery of one or more access openings. As a result, this gasket was relatively expensive to construct. By contrast, the present invention enables the use of a relatively inexpensive seal, such as a flat foam gasket made by a stamping process from a flat sheet of foam material. Moreover, the overall length of the seal is considerably less than the overall length of the prior art gasket, resulting in fewer areas where the integrity or sealing tightness of the seal could be compromised.
The base 16 and the wall 18 of the lower section 12 together partially define a chamber 34 for receiving a stacked array of integrated circuit wafers such as semiconductor wafers. The wafers are not shown in the drawings, but generally resemble thin disks of material having a diameter smaller than the inner diameter of the wall 18. The wafers are preferably separated by circular sections of resilient packaging material such as polymeric sheet material. Preferably, circular sections of foam material are provided in the chamber 34 above and below the stack of wafers and compressed when the container 10 is closed to provide cushioning.
The container 10 also includes four latches 36 having a generally overall, U-shaped configuration. Each latch 36 has two end portions with apertures 38 (
When the sections 12, 14 are assembled together, a middle portion of each latch 36 is received in a notch 42 (
A total compression force on the sections 12, 14 of preferably less than about 30 pounds, and more preferably less than about 10 pounds, is needed to compress the seal 26 sufficiently to close the container 10 and latch the latches 36. Preferably, the ribs 22 each have a generally “U” or “V”-shaped cross-sectional configuration that tapers to a lowermost, slightly rounded edge. This edge provides local regions where the seal 26 is sufficiently compressed and helps to avoid the need of compressing larger regions of the seal 26, which might otherwise require a higher compression force to close the container 10. For example, with a low density foam material having a density in the range of two pounds to six pounds per cubic foot, a compression force of approximately 5.5 to 8.5 pounds will be needed to close the container 10 and latch the latches 36, when at least part of the cross-sectional area of the seal is compressed to a 25% compression.
The base 16 includes a bottom surface 44 (see, e.g.,
Optionally, one or more info pad plugs 50 are received in the info pad cavities 46. In the accompanying drawings, one plug 50 is shown, although other plugs may be provided as well. The presence and placement pattern of the plugs 50 in the holes 46 provides information relating to the type of wafers in the chamber 34.
Preferably, each plug 50 comprises a polymeric body 52 and an adhesive 54 for connecting the body 52 to the ledge 48. Preferably, the adhesive 54 is a high tack pressure sensitive adhesive. Preferably, the adhesive 54 has sufficient strength to reliably retain the plug 50 in the hole 46 during normal shipping, handling and manufacturing operations, but also enables the plug 50 to be removed from the hole 46 without undue effort when desired. Optionally, a lever-type hand tool may be used to pry the plug 50 from the hole 46 to facilitate disengagement of the plug 50 from the shoulder 48. An example of a suitable plug 50 is “Bumpon” brand bumper, no. SJ-5763, from 3M Company.
The container also includes a clamping plate 56 (
As illustrated in
The lower section 12 also includes two finger-gripping recesses 66 that extend along opposite sides of the base 16. Each recess 66 includes four side-by-side, parallel channels that are all inclined upwardly as the center of the base 16 is approached. The upward inclination of the channels facilitates gripping of the container 10 and helps to ensure that the container 10, when loaded with wafers, is not inadvertently dropped.
Preferably, the sections 12, 14 are integrally made using a polymeric material in a blow molding process. Suitable polymeric materials include olefinic materials such as polypropylene copolymer and high density polyethylene. Optionally, a static dissipative material such as carbon particles or fibers (including nanotubes) can be added to the polymeric material to enhance static dissipative properties to the container 10. Additional information regarding the construction of the sections 12, 14 is set out in the aforementioned U.S. Pat. No. 6,193,090 which is expressly incorporated by reference herein.
The embodiments described above exemplify the present invention, and other constructions are possible. Accordingly, the invention should not be deemed limited to the particular embodiments mentioned above, but instead only by a fair scope of the claims that follow along with their equivalents.
