EVALUATION ON QUALITY AND RELIABILITY OF SINGLE- SIDED AND DOUBLE-SIDED SOLDER JOINT

摘要

The reasons that lead to solder joint failure include: mismatch of the thermal coefficients of different materials with inherent design deficiency; thermal cycling; isothermal process; stress cycling and strain cycling and so on. In order to improve the electronic product design, manufacture yield and reduce cost, in this paper, the engineering management was used to design an accelerated life test (ALT) experiment to analyze the solder joint quality and reliability. The two accelerated stresses (thermal cycling stress and power cycling stress) were selected in the test. The thermal cycling stress is from (-20C) to (+90C). The power cycling is power on and off twice for one thermal cycle. Pull test was used for the samples passing the ALT test and the samples working in the regular environment. The scanning electron microscopy (BSe-SEM) was used to observe the cross-section of solder joint to show the weakest link. The root cause was analyzed for every micro image and BSe-SEM photo. The thermal dynamics theory was used to estimate the pressure created in the product and lead to failure. Finally, the advantage and disadvantage were compared for the single-sided solder joint and double-sided solder joint. Summarized the method used the system and engineering management to design the experiment. The suggestions were made to design engineer to choose the solder joint to improve product quality and reliability.