Browse Prior Art Database

Nondestructive Bond Quality Monitor For Resistance Bonds

IP.com Disclosure Number: IPCOM000075005D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Joshi, KC: AUTHOR

Abstract

The availability of a nondestructive means of indicating the strength of bonds is highly desirable for microelectronic packaging applications. This is a test indicating configuration, particularly adapted to nondestructively monitor and indicate the quality of a joint wherein wires are welded to a connector pin. Herein, the pins are typically 12 mil diameter KOVAR* with 400 - 500 mu of gold plating and the wires to be attached to the pins have a 3.5 mil diameter core with 100 - 150 mu of gold plating.

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Nondestructive Bond Quality Monitor For Resistance Bonds

The availability of a nondestructive means of indicating the strength of bonds is highly desirable for microelectronic packaging applications. This is a test indicating configuration, particularly adapted to nondestructively monitor and indicate the quality of a joint wherein wires are welded to a connector pin. Herein, the pins are typically 12 mil diameter KOVAR* with 400 - 500 mu of gold plating and the wires to be attached to the pins have a 3.5 mil diameter core with 100 - 150 mu of gold plating.

As illustrated, a resistance welding, current monitor, and bond quality indicating apparatus comprises a constant voltage power supply 1 electrically coupled to the wire 2 and pin 3 to be bonded. Connected in series with the welding circuit is a 40 microohm resistor 4 having voltage take-off taps 5 and 6. The current in the welding circuit is simultaneously integrated through the use of an integrator 7. A current trace produced from the current readings is a good indicator of the bond strength. The integrated area under a current-time trace is indicative of the quality of the bond between the wire 2 and pin 3.

This apparatus monitors the current during welding and indicates as unacceptable those welds which have an integrated area below a preestablished criteria. This limit can be set for each wire-pin combination by making a large number of bonds. * Trademark of Westinghouse Electric Corporation.

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