Adjustable height wafer box

An adjustable height wafer box for the transportation of coin-stacked semiconductor wafers is disclosed. The adjustable height wafer box comprises a base plate, a cover plate, a plurality of ring insert plates and elastomer bumpers. The ring insert plates are stacked so as to successively engage one another, as well as engaging the base plate and the cover plate. The elastomer bumpers are engaged between successive ring insert plates and extend inwardly into the wafer containment space. The number of ring insert plates can be chosen to adjust the height of the wafer box in accordance with the number of coin-stacked semiconductor wafers to be shipped.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains to a box for the transportation of semiconductor wafers. In particular, this invention pertains to such a box with walls that are adjustable in height so as to accommodate the number of coin-stacked wafers to be transported.

2. Description of the Prior Art

In the prior art, there are many boxes for the transportation of coin-stacked semiconductor wafers. However, typical prior art wafer boxes have a fixed size for a fixed number of semiconductor wafers. As a result, the volume of shipping containers and dunnage material is the same regardless of the number of wafers enclosed within the wafer box. This can increase the shipping costs associated with a “partial run” which is typically defined as less than twenty-four wafers.

Examples of some prior art are U.S. Pat. No. 6,193,068 entitled “Containment Device for Retaining Semiconductor Wafers” issued on Feb. 27, 2001 to Lewis et al.; U.S. Pat. No. 6,286,684 entitled “Protective System for Integrated Circuit (IC) Wafers Retained Within Containers Designed for Storage and Shipment” issued on Sep. 11, 2001 to Brooks et al.; U.S. Pat. No. 6,003,674 entitled “Method and Apparatus for Packing Contaminant-Sensitive Articles and Resulting Package” issued on Dec. 21, 1999 to Brooks; and U.S. Pat. No. 5,724,748 entitled “Apparatus for Packaging Contaminant-Sensitive Articles and Resulting Package” issued on Mar. 10, 1998 to Brooks et al. Also of interest is U.S. patent application Ser. No. 10/507,471 entitled “Wafer Box with Radially Pivoting Latch Elements” filed on Sep. 10, 2004 by Forsyth.

OBJECTS AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a box for semiconductor wafers which is adjustable in size in order to reduce the volumetric space required for shipping partial lots of semiconductor wafers.

This and other objects are achieved by providing a wafer box with a base plate, a plurality of ring insert plates, and a cover plate. The wall height is varied by varying the number of ring insert plates stacked and assembled between the base plate and the cover plate. The ring insert plates are generally ring-shaped and include an upper circular ridge and a lower circular groove. The upper circular ridge of a ring insert plate is received by the lower circular groove of an upwardly successive ring insert plate. The upper circular ridge of the uppermost ring insert plate is received by a lower circular groove in the cover plate. Likewise, the base plate includes a ridge which is received by the groove in the lowermost ring insert plate. The ring insert plates further include notches to receive elastomer bumpers to act as cushions to the wafers inserted into the assembled box.

The inner diameter of the ring insert plates is chosen to accommodate the desired size of the semiconductor wafers, with allowance for the elastomer bumpers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings in detail, wherein like numerals refer to like elements throughout the several views, one sees thatFIG. 1is a top plan view of the adjustable height wafer box10of the present invention (with the cover plate removed) and thatFIG. 2is a cross-sectional view of the adjustable height wafer box10of the present invention. Adjustable height wafer box10includes base plate12, ring insert plates30, cover plate50and elastomer bumpers60. Wafer containment space70is formed within adjustable height wafer box10. A typical material for the base plate12, ring insert plates30and cover plate50is polyethylene plastic and a typical material for elastomer bumpers60is extruded soft or semi-soft plastic, but those skilled in the art will recognize a range of equivalents after review of this disclosure.

Base plate12comprises planar floor14, outer cylindrical wall16, upper circular ridge18recessed from outer cylindrical wall16, and inner circular ridge20extending upwardly from planar floor14and inwardly adjacent from upper circular ridge18. Gap22is formed between upper circular ridge18and inner circular ridge20. Ledge24is formed in the transition from outer cylindrical wall16to upper circular ridge18.

Ring insert plates30are generally ring-like in shape with a cross section with a lower outer leg32and a lower inner leg34. The periphery of lower outer leg32aligns with outer cylindrical wall16of base plate12and lower inner leg34aligns with inner circular ridge20of base plate12. The space between lower outer leg32and lower inner leg34forms lower circular groove36. The cross section of ring insert plates30further includes upper outer leg38and upper inner leg40. The diameter of upper outer leg38is substantially the same as that of upper circular ridge18of base plate12whereas the diameter of upper inner leg40is substantially the same as inner circular ridge20of base plate20. Gap42is formed between upper outer leg38and upper inner leg40. Ledge44is formed at the transition from lower outer leg32to upper outer leg38. The profile of ledge44, upper outer leg38, gap42and inner upper leg40is substantially the same as the profile of ledge24, upper circular ridge18, gap22and inner circular ridge20of base plate12. This allows lower outer leg32and lower inner leg34to engage either base plate12or a successively lower ring insert plate30.

Vertical gap46is formed between lower inner leg34of a given ring insert plate30and upper inner leg40of a successively lower ring insert plate30. A substantially identical vertical gap48is formed between the lower inner leg34of the lowest ring insert plate30and inner circular ridge20of base plate12.

Cover plate50comprises planar top52, outer circular ridge54about a periphery of planar top52and inner circular ridge56inwardly adjacent to outer circular ridge54. Outer circular ridge54and inner circular ridge52align with lower outer leg32and lower inner leg34, respectively, so as to present a lower profile which is substantially equal thereto. This allows cover plate50to engage the uppermost ring insert plate30. Vertical gap58, substantially identical to vertical gaps46,48, is formed between inner circular ridge56and the upper inner leg40of the highest ring insert plate30.

Elastomer bumpers60include inner bumper pad62joined to outer support element64by cross-support element66to form an H-type configuration. Elastomer bumpers60are installed so that cross-support elements66pass through vertical gaps46,48,58, and inner bumper pads62are inwardly adjacent from lower inner leg34and upper inner leg40thereby extending into and defining wafer containment space70. Outer support element64is engaged within the space bounded outwardly by upper outer leg38and bounded inwardly by upper inner leg40of a given ring insert plate30and the lower inner leg34of a successively upward ring insert plate30. Similarly, the outer support element64of the lowest elastomer bumper60is engaged within the space bounded outwardly by upper circular ridge18and bounded inwardly by inner circular ridge20of base plate12and the lower inner leg34of the lowest ring insert plate30. The outer support element64of the highest elastomer bumper60is engaged within the space bounded outwardly by upper outer leg38of the highest ring insert plate30and bounded inwardly by upper inner leg40of the highest ring insert plate30and the inner circular ridge56of cover plate50.

To use adjustable height wafer box10, the user starts with base plate12and installs the lowest elastomer bumpers60. The user then alternates installing a ring insert plate30and elastomer bumpers60(typically at least four elastomer bumpers would be required around the periphery of wafer containment space70between each successive ring insert plate30). The user chooses the appropriate number of ring insert plates30to construct a wafer box10with the appropriate height for the number of semiconductor wafers (not shown) to be shipped. The user would then insert the semiconductor wafers and place the cover plate50over the highest ring insert plate30to complete the wafer box10. The user would then use any number of methods to secure the wafer box10from disassembly. One way to secure the wafer box10from disassembly would be to place the completed and filled wafer box10into a shipping container100and secure the shipping container with straps200with Velcro or similar buckles300as shown inFIGS. 3 and 4.

Alternately, for the shipment of a small number of semiconductor wafers, the ring insert plates30can be omitted, with the base plate12attached to the cover plate50with the elastomeric bumpers60and a small number of semiconductor wafers therebetween.

Thus the several aforementioned objects and advantages are most effectively attained. Although a single preferred embodiment of the invention has been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims.