Dynamic fatigue and failure behavior of silver-filled electronically conductive adhesive joints at ambient environmental conditions

Abstract

Electronically-conductive adhesives (ECAs) have been used for electronics packaging applications. Today this technology is used in electronics for laptop computers, camcorders, watch electronics, hard-drive suspensions and in various other electronic equipments. Even though ECAs have excellent potential for being efficient and less costly alternative to lead-solder interconnects, they still possess a number of problems with respect to durability and design to meet specific needs. One of the issues that requires understanding is the fatigue behavior due either to mechanical or thermal stresses varying in a cyclic manner. This study intends to address the fatigue and failure behavior of ECAs under ambient operating conditions. For this purpose, joints were prepared using stainless steel adherend specimens bonded with a commercial ECA, and tested using monotonic and cyclic loadings at ambient environmental conditions (28°C and 20% relative humidity). S–N curves were generated using these specimens at four different load-ratios (R), namely 0.1, 0.3, 0.5, 0.7 and 150 Hz cyclic frequency. The S–N curves were not parallel, exhibited non-linear behavior with diminishing slope at higher R values.