Thermal behavior of flip chip LED packages using electrical conductive adhesive and soldering methods

This paper investigated thermal behavior of three kinds of FC packages connected with AuSn, SAC305, and electrical conductive adhesive using 1-D thermal resistance circuit method, and finite element method as well as experimental measurements. Simulation results indicated that the low thermal conductivity of electrical conductive adhesive led to high thermal resistance at this layer and decreased the thermal dissipation of the package as a bottleneck when the heat power was 0.74W in this study. The junction temperature and Rjc of adhesive package was much higher than the other two and led to package failure. SAC soldering package showed similar heat dissipation ability with the AuSn one. Additionally, the results of FE analysis show better agreement with experimental observation compared with 1-D thermal resistance circuit method.