BACKGROUND ART In view of the trend for higher and higher packing densities for semiconductor integrated circuits or chips, there has been developed in recent years by electronic manufacturers extremely miniaturized rectangular plate- shaped parts of the type having no terminal leads, such as pin grid array packages. Some of these types of pin grid array package structures are formed with solder balls on their bottom surface rather than with external terminal pins and are referred to as"ball grid arrays" (BGA) packages. Over the years, these BGA packages of this type are becoming even smaller with extraordinary small outer dimensions and are sometimes referred to as "micro ball grid arrays" (BGA) packages. For example, a typical HBGA package having forty-four solder balls on its bottom surface may have a length dimension of about 11 mm, a width dimension of about 6 mm, and a thickness of approximately 2 mm.

During the manufacturing of the HBGA packages, these packages are stored in and transported to and from various types of processes or manufacturing equipment for carrying out different manufacturing or assembling steps.

For instance, the GBGA packages may be assembled, marked, tested, inspected, and the like during which time the packages are handled and transported between the various

manufacturing processes and/or machines. Further, after the processing steps have been completed the ßBGA pack- ages are also packed and transported from a chip manu- facturer's site to an assembly station at a customer's site where further assembly operations are performed.

Heretofore, there is known in the prior art of a chip carrier tray with a cover having a plurality of separate compartments or pockets for accommodating a number of individual HBGA packages spaced apart from each other. Such a prior art chip carrier tray with a cover is illustrated in Figure 1. The chip carrier tray 2 and the cover 4 are both formed of a general square-shaped configuration. The tray 2 includes a plurality of separate compartments 6 each being capable of holding therein a single uBGA package 8. However, this prior art chip carrier tray with cover suffers from the disadvantage that the cover must be removed and each of the individual ßBGA packages in the separate compartments of the carrier tray must then be manipulated in order to inspect the solder balls on the respective bottom surfaces. Thus, this inspection process has become a very time-consuming and costly task to perform.

Therefore, it would be desirable to provide an im- proved chip carrier tray and flippable cover for effec- tively and efficiently packing and/or shipping a plurality of HBGA packages so as to facilitate their handling and transportation during the various steps of manufacturing and/or assembly and subsequent shipping to the customer. Further, it would be expedient that the cover is flippable so as to facilitate the inspection of the solder balls on the bottom surfaces of the ßBGA packages.

DISCLOSURE OF INVENTION It is a general technical advantage of the present invention to provide an improved ßBGA carrier of a

generally square-shaped configuration which is relatively simple and economical to manufacture and assemble, but yet overcomes the disadvantages of the prior art BGA carriers.

It is a technical advantage of the present invention to provide an improved chip carrier tray and cover for effectively and efficiently packing and/or shipping a plurality of ßBGA packages so as to facilitate their handling and transportation during the various steps of manufacturing and/or assembly and subsequent shipping to a customer.

It is another technical advantage of the present invention to provide an improved chip carrier formed of a tray and a cover in which the cover is flippable so as to facilitate the inspection of the solder balls on the bottom surfaces of the HBGA packages.

It is still another technical advantage of the present invention to provide an improved GBGA carrier for packing and shipping of a plurality of ßBGA packages which includes a tray member having a plurality of first pockets and a lid member having a plurality of second pockets aligned with corresponding ones of the plurality of first pockets.

It is yet still another technical advantage of the present invention to provide an improved HBGA carrier which is made of an inexpensive material and construction, but yet is relatively durable and re- usable.

In accordance with these aims and objectives, the present invention is concerned with the provision of an improved uBGA carrier for packing and shipping of a plurality of ßBGA packages which includes a substantially square-shaped tray member and a substantially square- shaped lid member. The tray member is formed of a ledge portion and a centrally raised platform surrounded on each side by the ledge portion. The centrally raised

platform has a plurality of first pockets disposed therein for packing and storing the plurality of ßBGA packages. The lid member is formed of a raised lip portion and a central cavity portion surrounded on each side by the lid portion. The central cavity portion has a plurality of second pockets formed therein which are vertically aligned with corresponding ones of the plurality of first pockets in the tray member when the lid member is placed on top of the tray member. The uBGA carrier is flippable upside down so that when the tray member is removed the solder balls on the bottom surfaces thereof are facing upwardly to facilitate inspection of the same.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and advantages of the present invention will become more fully apparent from the following detailed description when read in con- junction with the accompanying drawings with like reference numerals indicating corresponding parts throughout, wherein: Figure 1 is an exploded, perspective view of a chip carrier tray with cover of the prior art; Figure 2 is an exploded, perspective view of a chip carrier tray with a flippable cover, constructed in ac- cordance with the principles of the present invention; Figure 3 is a top plan view of the carrier tray of Figure 2 ; Figure 4 is a bottom plan view of the carrier tray of Figure 2; Figure 5 is a cross-sectional view of the carrier tray, taken along the lines 5-5 of Figure 3; Figure 6 is a cross-sectional view of the carrier tray taken along the lines 6-6 of Figure 3; Figure 7 is an enlarged view of the encircled area A of Figure 3;

Figure 8 is a top plan view of the carrier cover of Figure 2; Figure 9 is a bottom plan view of the carrier cover of Figure 2; Figure 10 is a cross-sectional view of the carrier cover, taken along the lines 10-10 of Figure 9; and Figure 11 is an enlarged perspective view of one of theZBGA packages.

BEST MODE FOR CARRYING OUT THE INVENTION Referring now in detail to the drawings, there is shown in Figure 2 an improved ßBGA carrier 10 which is constructed in accordance with the principles of the present invention. The ßBGA carrier is comprised of a novel tray 12 and a flippable cover 14 for packing and shipping a plurality of micro ball grid array (BGA) packages 16 and is specially adapted for facilitating the inspection of the solder balls on the bottom surfaces of the pBGA packages. The details of the carrier tray 12 are illustrated in Figures 3-7, and the details of the flippable carrier cover 14 are depicted in Figures 8-10.

Each of the ßBGA packages 16 (one of which is illustrated in detail in Figure 11) is of a substantially rectangu- larly-shaped configuration and includes opposed side edges 18, opposed end edges 20, a top surface 22, and a bottom surface 24. The bottom surface 24 is provided with a plurality of solder balls 26 which are arranged in a matrix configuration. TheZBGA package 16 may be similar to the type commercially available from Advanced Micro Devices, Inc. of Sunnyvale, California, under their part No. AM29LV800-120UAC. In this instance, the GBGA package 16 has forty-four solder balls 26 formed on its bottom surface 24.

With reference to Figures 2, and 3 through 7, the BGA carrier tray 12 is of a substantially square-shaped configuration and has width and length dimensions of ap-

proximately 101.6 mm. The carrier tray 12 is formed with a plurality of individual compartments or pockets 28 which are arranged in a matrix of rows and columns. For example, the pockets 28 may be arranged into six rows and ten columns so as to pack or store sixty ßBGA packages 16 therein. The carrier tray is of a single-piece construction and is preferably formed of a suitable plastic material such as polyethylene which may be fabricated by a conventional injection molding process.

It should be noted that while the pockets 28 may have various width and dimensions, they are all made of the same size so as to conform to the contour of the GBGA packages 16 for storing a predetermined quantity thereof, for example, sixty.

As can be seen from Figures 3-7, the carrier tray includes a narrow ledge portion 30 and a centrally raised platform 32 surrounded on each side by the ledge portion 30. The plurality of pockets 28 are formed in the raised platform 32. Since all of the pockets 28 are identical in their construction, it will be sufficient to describe in detail only one of them. The pocket 28 is of a gen- erally rectangularly-shaped configuration and has dimen- sions of about 11.07 mm in length and about 5.94 mm in width. The pocket is formed by opposed raised end sup- port members 34a, 34b and a slightly stepped central por- tion 36 sandwiched between the support members. Further, the step portion 36 is formed with an aperture 38 dis- posed in its center. The step portion 36 has dimensions of approximately 6.86 mm (in length) and of approximately 5.08 mm (in width). The aperture 38 has dimensions of about 3.3 mm x 2.54 mm.

In this manner, when the ßBGA packages 16 are dis- posed in the individual pockets 28 of the carrier tray 12 only the bottom surface 24 adjacent the opposed end edges 20 of the xbBGA packages 16 are supported by means of the opposed raised end support members 34a, 34b so that the

solder balls 26 thereof on the bottom surface are sus- pended freely above the stepped portion 36. As a result, the solder balls 26 are substantially aligned over the aperture 38 and do not contact or engage with any part of the pocket 28. This can best be seen from Figure 6.

This serves to reduce the possibility of physical damage to the sensitive parts on the bottom surface portions of the uBGA packages 16. In addition, ventilation is provided to the ßBGA packages 16 by the apertures 38, such as when the carrier tray 12 filled with HBGA is placed into an oven for temperature testing.

With reference to Figures 2 and 8 through 10, the ßBGA flippable carrier cover 14 is also of a substan- tially square-shaped construction and has likewise width and length dimensions of approximately 101.6 mm. The flippable carrier cover 14 is formed with a plurality of individual compartments or pockets 40 which are arranged in a matrix of rows and columns. For instance, the pockets 40 are formed into six rows and ten columns. The flippable carrier cover is of a single-piece construction and is also preferably formed of a suitable plastic material such as polyethylene which may be fabricated by a conventional injection molding process. Again, the pockets 40 are all made of the same size and conform to the contour of the 4BGA packages.

As can be seen from Figure 9, the carrier cover 14 includes a narrow raised lip portion 42 and a central cavity portion 44 surrounded on each side by the lip por- tion 42. The plurality of pockets 40 are formed in the central portion 44. Each of the pockets 40 is of a generally rectangular shape and has dimensions of about 11.07 mm in length and about 5.94 mm in width.

In use, a predetermined number of uBGA packages 16 (i. e., sixty) are loaded or packed into the corresponding pockets 28 of the carrier tray 12 so as to completely fill the same. As can best be seen from Figure 6, it

will be noted that the opposed raised end support members 34a, 34b contact or engage only the bottom surface 24 ad- jacent the opposed end edges 20 of the ßBGA packages 16 so that the solder balls 26 on the bottom surface thereof are suspended freely above the stepped portion 36 and are substantially aligned over the aperture 38. With the carrier tray 12 being filled with uBGA packages, they may now be transported to and from various types of proces- sing or manufacturing equipment for carrying out various manufacturing or assembly steps, such as assembling, marking, testing and inspection.

As part of the typical inspection process conducted at the manufacturer's site, the solder balls 26 on the bottom surface 24 of the GAGA packages 16 are visually inspected for compliance with quality standards. Unlike the prior art carrier trays in which each of the individual uBGA packages must be manipulated in order to inspect the solder balls on the bottom surface, the flip- pable carrier cover 14 of the present invention is used to flip over the plurality of uBGA packages 16 in the corresponding pockets 28 so as to facilitate the inspec- tion of the solder balls 26. In particular, the flip- pable carrier cover 14 is disposed on top of and over the carrier tray 12 filled with the BGA packages 16. As a consequence, the lip portion 42 of the carrier cover 14 will come to rest against the ledge portion 30 of the carrier tray 12 so that the cover pockets 40 will be vertically aligned with the tray pockets 28 having the GBGA packages 16 disposed therein.

Next, the carrier tray 12 and cover 14 will be turned over or flipped upside-down so that the ßBGA packages 16 are disposed in the corresponding cover pockets 40 with the solder balls 26 facing upwardly.

Then, the carrier tray 12 can be lifted away from the flippable carrier cover 14 so as to allow the solder balls 26 to be visually inspected (Figure 2). In order

to place the uBGA packages 16 back into the tray pockets 28, the operations just described are performed in the reverse order. Therefore, when all of the remaining processing steps have been completed the carrier 10 is suitably transported from the chip manufacturer's site to an assembly station at a customer's site where further assembly operations can be performed. Therefore, the overall assembly operation has been greatly simplified and the packing cost of the ßBGA packages 16 has been significantly reduced. It is also to be noted that the GAGA carrier 10, after it has been completely unloaded at the customer's site, can be reused since it is made of a durable plastic material.

From the foregoing detailed description, it can thus be seen that the present invention provides an improved GBGA carrier for packing and shipping of a plurality of uBGA packages and is specially adapted for facilitating the inspection of the solder balls on the bottom surfaces of the x2BGA packages. The GBGA carrier of the present invention includes a tray member having a plurality of first pockets and a lid member having a plurality of second pockets. When the lid member is placed on top of the tray member, the second pockets are vertically aligned with corresponding ones of the first pockets in the tray member. Thereafter, the HBGA carrier can be flipped upside down so that when the tray member is removed the solder balls are facing upwardly to allow in- spection of the same.

While there has been illustrated and described what is at present considered to be a preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made, and equivalents may be substituted for elements thereof without departing from the true scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the

teachings of the invention without departing from the central scope thereof. Therefore, it is intended that this invention not be limited to the particular embodi- ment disclosed as the best mode contemplated for carrying out the invention, but that the invention will include all embodiments falling within the scope of the appended claims.