[IEEE Proceedings of the 11th International Symposium on the Physical and Failure Analysis of Integrated Circuits. IPFA 2004 - Taiwan (5-8 July 2004)] Proceedings of the 11th International Symposium on the Physical and Failure Analysis of Integrated Circuits. IPFA 2004 (IEEE Cat. No.04TH8743) - Discoloration related failure mechanism and its root cause in electroless nickel immersion gold (ENIG) pad metallurgical surface finish