Reliability studies of two flip-chip BGA packages using power cycling test

Abstract

Power cycling tests of the second level reliability of two flip-chip BGA packages are discussed in this paper. The first one is for a flip-chip on laminate package (FCPBGA) and the other for a flip-chip on ceramic package (FCCBGA). For the FCPBGA, test strategies will be first discussed and then focus will be given to a unique failure mode associated with this type of packages assembled back to back onto printed circuit board. Instead of anticipated failures of the corner solder joints under the die shadow, as in the case of wire-bonded packages, we found that solder joints failed first in the central region of the package and then failures of solder joints spread out in the radial direction from the center of the package. Explanation will be given to the physical mechanisms that caused this type of failure. For the FCCBGA, the improved test strategies based on what has been learned from the test of FCPBGA will be presented and focus will be given to the effect of different parameters on the second level reliability of the package. Here, because of the increased rigidity of the ceramic substrate solder joints failed as expected first at the corner(s) of the ceramic substrate. Based on the test results and the modified Coffin–Manson equation, predictions or the solder joint fatigue life will be shown.