The Degradation of Bonding Wires and Sealing Glasses with Extended Thermal Cycling

The purpose of this investigation was to determine if there was a detrimental effect on internal bonded wires of ceramic dual-in-line and ceramic flat packages, which had been subjected to thermal cycling for up to 1000 cycles. Several manufacturers\´ parts were used - three ceramic dual-in-line packages (CDIP) and two flat packages. All parts were stressed to MIL-STD-883, Method 1010, Condition C (¿65°C. to +150°C) or Method 1011, Condition C. Samples were removed at various steps throughout the cycling program. All parts were decapped and wires pulled. Pull strength and failure locations were recorded. This investigation indicated that end-of-life due to temperature cycling, can be observed to start within 1000 cycles, but due to the slow mean degradation rate, the calculated mean cycles to failure is very large (>1018 cycles). Thermal shock cause much less degradation of the wire bond strengths than did temperature cycling at this condition C level. The results show that Method 1010-C does cause slight degradation in mean pull strength, almost no degradation in maximum value observed, and extensive degradation to lowest values observed. Zero wirepull strengths were obtained after 240 temperature cycles and "percent fail less than 0.5 gram-force" increases significantly with increasing cycles from 240 to 1000. The purpose of the second part of this investigation was to determine if there was a degradation in CERDIP sealing glass strength of parts subjected to 1000 cycles of MIL-STD-883, Method 1011, Condition A (0 - 100°C) Thermal Shock.