Solder Joint Shape Optimization for Ceramic Leadless Chip Carriers

Abstract

ABSTRACT In this paper, the solder joint shape of ceramic leadless chip carriers is optimized in order to obtain longer lifetime. Six different leadless ceramic SAW-filter packages were selected for the solder joint reliability tests. For each package type there were two solder pad versions, a “short” and a “long” one. Six test boards containing four samples of each package type were included in the thermal cycling test. The total number of package samples was thus 144. The thermal cycling test was conformable with IPC-9701, TC3. Stress-dependent Engelmaier’s model was utilized in order to interpret the test results. The lifetime estimations in varying use conditions were created based on this model. After doing this, the lifetime predictions in the real environment were given by utilizing Response Surface Methodology (RSM). Based on the findings, the fatigue life can be extended by up to 30 % simply by solder pad length optimization.