Abstract
With the trend of multi-function and minimizing volume, original electronic package type has not met the performance of new-generation product. Consequently, new type packages based on WLP and CSP skills are developed to achieve the demand of reliability.New WL-CSP with stress buffer layer and bubble-like plate are proposed to improve the solder joint fatigue life. Therefore the thermal stress caused by CTE mismatch could be reduce. Finally, the reliability of the WLP with larger die size could be enhanced by this new design.In order to realize the relationship of the solder joint fatigue life, stress buffer layer and bubble-like plate, a finite element parametric analysis applying software ANSYSa is utilized. The design parameters include the thickness of stress buffer layer, thickness, bending angle and height of different type bubble-like plate.It could be found in the FEM analysis results that the stress buffer layer and bubble-like plate can not only relax the thermal stress of solder joints but also achieve the goal of enhancing package reliability. However, the relationship between each parameter and solder joint fatigue life has a dissimilar trend. Finally, the peeling stress between stress buffer layer as well as two different type bubble-like plate is discussed and the stress state of leadframe is also analyzed in the research.