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Flexible Shorting Apparatus

IP.com Disclosure Number: IPCOM000041027D
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Baker, DE: AUTHOR [+3]

Abstract

A simple and reliable method of electrically shorting items on irregularly or flat surfaces is described.

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This is the abbreviated version, containing approximately 93% of the total text.

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Flexible Shorting Apparatus

A simple and reliable method of electrically shorting items on irregularly or flat surfaces is described.

Wafer testing tools use a space transformer assembly 10 to spread chip probe signals out to a workable pattern of lands 12. These lands 12 are in turn connected to a tester. A common problem of the transformer 10 is that the gold plated tips of the probes 14 wear off, thereby degrading the chip contact and reducing the test yields. To repair the costly transformers, a replating operation is done which requires all the probes 14 to be sorted to ground. The flexible shorting apparatus 16 was designed to sort all the lands 12 to ground on the backside of the transformer 10, which in turn shorts the probes 14 while leaving them accessible for the replating operation.

Apparatus 16 utilizes a conductive cloth 18 to fit over a foam padding material 20. Retaining ring 22 holds the cloth 18 around the foam 20 and grounds the cloth 18 to base surface 24. Shorting of the lands 12 is via physical contact pressure between the lands 12 and the cloth 18 due to the weight of the transformer 10 and foam compression.

The flexing properties of the foam allow for shorting of surfaces with irregularities as well as shorting of contoured surfaces. By changing the foam consistency, the cloth can be kept in contact with a variety of irregularly contoured surfaces. In the preferred embodiment, the conductive cloth 18 is im- pregnated with graphite, but it...