Carrier for Semiconductive Wafers

This invention relates generally to carriers for semiconductive wafers and, more particularly, to such carriers having provision for impeding spillage of semiconductive wafers therefrom during manual handling of the carriers.

Carriers for holding twelve, twenty-four or more spaced semiconductive wafers each are employed in many types of semiconductive wafer processing systems to facilitate batch processing and to minimize damage of the wafers due to improper handling. Such carriers are employed, for example, as input magazines for sequentially supplying semiconductive wafers to automatic wafer handling and processing systems, or as output magazines for sequentially receiving processed semiconductive wafers from such systems, or as intermediate (throughput) devices for holding semiconductive wafers that may require sampling, testing, or some other special handling at some point during processing by such systems. In nearly all of these cases the carriers must, at some point, be manually transported to or from such systems with the attendant risk that in so doing the semiconductive wafers may slip from the carriers and thereby be damaged or broken. This risk is particularly great in the case of carriers of the type permitting unobstructed passage of semiconductive wafers therethrough. If such carriers are tilted slightly forward or backward while they are being manually transported, any semiconductive wafers contained therein will slide out. Although this risk is much less critical in the case of a carrier of the type permitting passage of semiconductive wafers into or out of the carrier from only one end of the carrier, care must still be exercised while such a carrier is being manually transported to avoid tilting it downward in the direction of its open end.

Past efforts to eliminate the risk of spilling semiconductive wafers from carriers while they are being manually transported have resulted in elaborate switching mechanisms for locking the semiconductive wafers in place in the carriers during manual transport thereof. However, the person transporting the carriers has to remember to actuate the switching mechanism before picking up the carriers or run the risk of spilling the semiconductive wafers contained therein, in which event, the risk is, in fact, not reduced at all. Moreover, when placing the carriers in a semiconductive wafer handling and processing system the person transporting the carriers also has to remember to deactuate the switching mechanisms in order to release the semiconductive wafers to the handling and processing system. In addition to these drawbacks, such switching mechanisms are generally complex and add significantly to the cost of the carriers.

The principal object of this invention is to provide an improved carrier for semiconductive wafers that is automatically operable when picked up to impede spillage of the semiconductive wafers from the carrier and that is automatically operable when set down to release the semiconductive wafers.

Another object of this invention is to provide an improved carrier of the foregoing type that is simple in design and operation and that is not significantly more expensive than a standard carrier.

These objects are accomplished in accordance with the illustrated preferred embodiment of this invention by providing a carrier having a pair of fixedly-spaced oppositely-facing side plates forming a plurality of transport channels arranged in parallel stacked relationship for receiving a like plurality of semiconductive wafers. In each side plate a recessed region is provided extending partially into the transport channels and having a spring-loaded stop member pivotally mounted therein. In response to the carrier being set down, each stop member is activated to automatically permit passage of the wafers through the channels (i.e., to not block the channels), and in response to the carrier being picked-up, stop member is activated to automatically block the channels and prevent wafer spillage by inhibiting passage of the wafers through the channels.

FIG. 1 is a perspective view, of the carrier of the present invention when carrier is set down upon a surface.

FIG. 2 is a side view of the carrier of FIG. 1 showing the orientation of one of the stop members when the carrier is set down upon the surface.

FIG. 3 is a top view of the carrier of FIG. 1 when the carrier is lifted from the surface.

FIG. 4 is a side view of the carrier of FIG. 1 showing the orientation of one of the stop members when the carrier is lifted from the surface.

FIGS. 5 and 6 are cutaway views of a portion of the carrier of FIG. 1 showing one of the cam housings, and the position and orientation of one end of the stop member in that cam housing when the carrier is set down upon the surface and when the carrier is lifted from the surface, respectively.

Referring now to FIGS. 1, 2 and 3, there is shown a carrier 11 with two sides 13, each side having a plurality of flanges 15 and having a recessed region 17 with a shaft-support portion19, the shaft-support portion having an aperture 21 therethrough. The recessed region of each side 13 17 is bounded at one end (the top end) by a cam housing 23, and at the other end (the bottom end) by the shaft-support portion 19. Each cam housing 23 is affixed (for example, by screws) to the top end of corresponding side 13. The sides 13 are spaced apart a selected distance, with the flanges 15 positioned facing each other such that corresponding pairs of consecutive flanges on each side 13 form stacked parallel transport channels 25 into which semiconductive wafers or the like may be placed. Rods 27, which are anchored (e.g., riveted or screwed) to the sides 13, serve to fix the position and distance of the sides 13 with respect to each other. The recessed region 17 of each side 13 extends partially into the flanges 15 and into the transport channels 25 at a selected angle substantially perpendicular to the flanges and the transport channels.

A spring-loaded stop member (flag shaft) 29 is pivotally mounted in each recessed region 17. Each stop member 29 comprises a top shaft portion 31, a middle or flag portion 33, and a bottom shaft portion 35, the top shaft portion 31 being disposed for pivotal and translational movement within the corresponding cam housing 23 and the bottom shaft portion 35 being disposed for translational movement through aperture 21 of the corresponding shaft-support portion 19. A cam slot 37 is provided in each cam housing 23. A cam follower pin 39 is provided at the end of the top shaft portion 31 of each stop member 29 for prescribed movement within the cam slot 37 of the corresponding cam housing 23. Each stop member 28 has a compressible spring 41 disposed about the top shaft portion 31 between the flag portion 33 and the base of the corresponding cam housing 23.

As shown in FIGS. 1, 2, 3 and 4, bottom shaft portions 35 of stop members 29 may be inserted (pushed) fully into apertures 21 or may extend a selected length from the bottom of shaft-support portions 19. For example, in response to carrier 11 being placed (set down) upon a surface 42 as shown in FIGS. 1 and 2, bottom shaft portions 35 are fully inserted into apertures 21, compressing springs 41 and inserting top shaft portions 31 further into cam housings 23 as shown in FIG. 5. As the top shaft portions 31 translate (are inserted) further into cam housing 23, cam follower pins 39 are made to traverse or follow cam slots 37 in an upward and outward direction causing flag portions 33 of stop members 29 to turn outward (away) from recessed region 27, thereby releasing (not binding or blocking) any wafers that may stored in the transport channels 25 of the carrier 11. In response to carrier 11 being picked up or being raised from the surface 42 as shown in FIGS. 3, 4 and 6, springs 41 are released from their compressed state and push down upon flag portions 33 causing bottom shaft portions 35 to extend through and from apertures 21 and causing cam follower pins 39 to move downward and inward within cam slots 37. This, in turn, causes flat portions 33 to turn inward and block items such as wafers that may be stored in the transport channels 25, thereby impeding the wafers from slipping or falling out of the carrier. It is understood that, for mechanical operation clearance purposes, the section of each top shaft portion 31 encircled by corresponding spring 41 when carrier 11 is picked up and the space in each cam housing 23 for receiving the corresponding top shaft portion 31 when the carrier is set down are each at least equal in length to the section of each bottom shaft portion 35 extending from the corresponding aperature 21 when carrier 11 is picked up.

In an alternative embodiment of the present invention, carrier 11 may comprise a third side and one or more stop members disposed as indicated hereinabove, this third side together with sides 13 forming a partial enclosure to prevent wafers from falling out of the carrier in the direction of the third side. In a further embodiment, the stop members may be disposed so as to stop spillage of wafers in opposite directions. For example, carrier 11 may comprise two sides, each having a stop member disposed so that, upon the carrier being picked up, one stop member would act to bind or block the wafers from the front and thereby prevent their spillage in a forward direction and the other stop member would act to bind or block the wafers from the rear and thereby prevent their spillage in a rearward direction.