Quantitative characterization of 96.5Sn3.5Ag and 80Au20Sn optical fiber solder bond joints on silicon micro-optical bench substrates

Stress analysis of optical fiber solder bond joints on silicon micro-optical bench substrates under thermal cycle loading was investigated using two-dimensional (2-D) and three-dimensional (3-D) finite element analyses. Finite element simulations were carried out to investigate the effect of the distance between the fiber and the silicon substrate for planar and v-groove solder attachment geometries. It was found that the maximum stress-strain along the interface of the solder and silicon substrate increases as the distance between the fiber and substrate decreases for both geometries. The solder bond strength under thermal loading was also examined to determine the influence of alternative solder material. Favorable results were obtained for 96.5Sn3.5Ag solder as compared to 80Au20Sn solder. If adequate space is provided between the fiber and silicon v-groove inclined walls, the reliability of the v-groove geometry is projected to be comparable to an optimally designed planar bond joint geometry.