Copper wire degradation under high temperature and high humidity without molding compound

In this study, the degradation of copper wire under high temperature and high humidity is investigated. Unbiased high temperature and high humidity accelerated stress test (uHAST) with a cumulative duration of 1,032 hours is conducted on copper wire test packages using ceramic dual inline package with custom bonding layout as the test vehicle. From the failure testing and analysis, most degradation observed happen during the first 504 hours. The electrical resistance of the copper wire bonding increases by <10%, which is much lower than the 20% guideline used in the industry. However, significant copper migration is observed after 840 hours which may cause failures. The wire bonding degradations after uHAST has been investigated by means of morphological and elemental tests.