Effect of Test Conditions on Electromigration Reliability of Sn–Ag–Cu Flip-Chip Solder Interconnects

Abstract

The high-temperature operation life test (HTOL) was conducted in this paper to study electromigration phenomena of solder interconnects in a flip-chip package assembly. We examined the fatigue reliability and morphological patterns of three solder compositions: Sn–4Ag–0.5Cu, Sn–3.5Ag–1Cu, and Sn–3Ag–1.5Cu, subjected to two test conditions consisting of different average current densities and ambient temperatures (5kA∕cm2 at 150°C and 20kA∕cm2 at 30°C). It is interesting to realize that as the Cu weight content of the solder composition increases, the fatigue life increases under 5kA∕cm2 at 150°C but decreases under 20kA∕cm2 at 30°C. Observed electromigration morphologies along with computed current density and temperature distributions on solder interconnects from the electrothermal coupling analysis were examined, correlated, and discussed.