Development of Nondestructive Pull Test Requirements for Gold Wires on Multilayer Thick-Film Hybrid Microcircuits

Thermosonic wire bonding !s used to attach 1-mil gold wires to muitilayer thick-film hybrid microcircuits manufactured by the Bendix Corporation, Kansas City Division, for the Department of Energy. A study was conducted to develop a realistic nondestructive pull test limit which would detect unacceptable wire bonds and would be compatible with production processes without applying excessive stress to the wires. The effect of environmental testing on wire bond strength was also examined. A 1.5-gf nondestructive pull test limit was incorporated into production which provided an adequate screen for unacceptable bonds without significantly increasing rework time and cost for wire failures. No degradation of wire bond strengths resulted from environmental testing.