Thermomechanical Testing Techniques for Microcircuits.
Final technical rept. Mar 1972-Dec 1974
MOTOROLA INC PHOENIX AZ SEMICONDUCTOR GROUP
Pagination or Media Count:
This study investigated the performance of more than 3,000 plastic and hermetic 14-lead integrated circuits in various temperature cycling and thermal shock step stress and extended cycle test sequences interaction between thermal shock preconditioning on temperature cycling and wire bond and seal strength degradation when subjected to more than 1,000 thermal cycles. Thermal analysis of 14-lead ceramic DIP was also studied. Glass transition temperature of the various plastics was measured. The latest plastic integrated circuit with large diameter wires was the best package on long term greater than 4,000 cycles thermal cycling. Flat packages were the best hermetic package. Major failure modes were grain boundary fracture in plastic integrated circuits and wire flex failures in hermetic. Temperature cycling affects the bonding wires whereas thermal shock affects the package hermeticity. Mean wire pull strength does degrade approximately 10 in 1,000 cycles, with some zero strength bonds occurring after 240 cycles. The ceramic dual-in-line glass seal shows an average degradation of 6.4 in-lbs1,000 cycles in strength with extended cycling. The mean number of cycles to failure was 7,800.
- Electrical and Electronic Equipment