Packaging leakage mechanism: investigation of copper sulfide growths

This paper describes analysis of subtle copper sulfide growths, leakage characteristics and the activation of the leakage mechanism during a high temperature process, on leaded and PBGA packages. The leakage levels on such failures tend to be in the range of tens of uA @1V , and an incorrect analysis path will destroy the leakage evidence and mechanism. During the experiments conducted, it was observed that the activated leakage mechanism could be de-activated and re-activated by heat and moisture. These experiments indicated that failures are latent and the device could fail due to environmental conditions.