Browse Prior Art Database

Non-Adhering Probe for Contacting Solder Pads

IP.com Disclosure Number: IPCOM000046217D
Original Publication Date: 1983-Jun-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Lorber, HW: AUTHOR [+4]

Abstract

By coating the end of a probe used for contacting the individual solder balls used for mechanically and electrically attaching a semiconductor device to a substrate with chromium, the adherence of the solder to the tip of the probe can be minimized.

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Non-Adhering Probe for Contacting Solder Pads

By coating the end of a probe used for contacting the individual solder balls used for mechanically and electrically attaching a semiconductor device to a substrate with chromium, the adherence of the solder to the tip of the probe can be minimized.

Semiconductor wafers containing many semiconductor devices fabricated as individual chips are provided with many individual solder balls on their back surface. Before the chips are broken apart and attached to a MLC (multilayer ceramic) substrate, it is necessary to test the integrity of the circuits in each chip by probing the solder balls which will subsequently make connection to the MLC substrate to form a pluggable module. The method of joining chips to a substrate is described in U. S. Patent 3,429,040.

A so-called "cobra" probe (because of its shape) is shown in the drawing. The probe material is typically fabricated of many metallic elements, for example, palladium, silver, gold, platinum and copper, with at least 55% being of noble metals and 30% of semi-noble metals. To minimize the adhesion of the lead-tin solder to the tip of the probe and thus increase the time between cleaning of the probe, it has been found to be advantageous to coat the tip of the probe with chromium. This reduces the adhesion of solder without prejudicing the required mechanical and electrical properties of the probe.

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