Browse Prior Art Database

Extended Pad for Testing Package Parts

IP.com Disclosure Number: IPCOM000044522D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Anderson, CJ: AUTHOR [+3]

Abstract

Extending a controlled collapse chip connection pad to provide a landing area for a test probe makes testing possible without serious circuit degradation. Modifying interior pads by forming distinct solder wettable areas for chip connection and for probing minimizes solder stealing problems in the extended pads. Probing package parts for electrical testing requires a large number of contacts (N 1000) which must probe the part without damage to the thin film structures. This structure allows the use of an existing probe technology buckling beam contact (BBC), to address pads formed by modifying the pad shape. The figure shows an enlargement of a small area of a typical silicon thin film multi-chip, or tile part, showing five pads. Each chip may have 100 or more pads and there are additional pads at each part edge.

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Extended Pad for Testing Package Parts

Extending a controlled collapse chip connection pad to provide a landing area for a test probe makes testing possible without serious circuit degradation. Modifying interior pads by forming distinct solder wettable areas for chip connection and for probing minimizes solder stealing problems in the extended pads. Probing package parts for electrical testing requires a large number of contacts (N 1000) which must probe the part without damage to the thin film structures. This structure allows the use of an existing probe technology buckling beam contact (BBC), to address pads formed by modifying the pad shape. The figure shows an enlargement of a small area of a typical silicon thin film multi- chip, or tile part, showing five pads. Each chip may have 100 or more pads and there are additional pads at each part edge. Of these pads, typically half, or more, must be addressed for testing. Addressing the pads at the slit edge is not a problem since metal lines can be patterned outside the tile to test pads which are later diced away, removing material 1 outboard of broken line 2. Such structures, if not removed, significantly degrade the package performance. Pad removal is not possible within the area of the chip occupied by pads 3 and 4. A modified pad, which can be addressed with a BBC array, uses the standard vertical structure. The small portion 5 of the pad 3 is aligned, and solder is joined to the chip. The larger portion 6...