Browse Prior Art Database

Wire Bond Nugget Removal Technique

IP.com Disclosure Number: IPCOM000048770D
Original Publication Date: 1982-Mar-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Eve, JL: AUTHOR [+3]

Abstract

As part of the QC (quality control) and process monitor activity for ceramic substrates, EC (engineering change) wires are conventionally bonded to top surface pads and then pulled to failure to assess the quality of the bond components. A normal product exhibits a failure mode wherein the wire fails at a point just above the bond, leaving the bonded wire section (the nugget) on the EC pad. See Figs. 1A and 1B.

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Wire Bond Nugget Removal Technique

As part of the QC (quality control) and process monitor activity for ceramic substrates, EC (engineering change) wires are conventionally bonded to top surface pads and then pulled to failure to assess the quality of the bond components. A normal product exhibits a failure mode wherein the wire fails at a point just above the bond, leaving the bonded wire section (the nugget) on the EC pad. See Figs. 1A and 1B.

Subsequent substrate operations require that these nuggets be removed. The removal operation must leave the EC pad in a testable state (i.e., minimal damage to the EC pad).

Present techniques include the use of an operator to manually remove the nugget using a dental pick or micro-chisel with the aid of a microscope.

This nugget can be removed (as shown in Figs. 2A and 2B) by using a torsional foot probe. The operator loads the substrate into a substrate holder, aligns the nugget to be removed with the torsion foot, and pushes a button. The foot twists through a pre-set angle first in one direction and then in the other direction, exerting an alternating shearing force on the nugget, causing it to separate at the wire to EC pad interface. The operation is consistent and automatic and imparts minimal change, if any, to the EC pads.

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