A comparison study of thermal aging effect on mold compound and its impact on leadframe packages stress

This report discloses an advanced approach to improve the prediction of electronic IC packages' reliability performance by studying packaging materials' thermo-mechanical properties at different high temperature storage conditions. Package level reliability has been well studied. However, during material screening stage, it is difficult to estimate the impact of IC packaging materials on package reliability performance based on typical material properties such as CTE, Tg and Storage Modulus determined at time zero stage. In this study, 3 types of Epoxy mold compounds (EMCs) were characterized with their thermo-mechanical properties by means of TGA, TMA and DMA at different 175°C high temperature storage (HTS) durations, i.e. 0hr, 1000hrs and 2000hrs respectively. Furthermore, simulation assessments for package stress are conducted for EMC evaluation at package level. The thermo-mechanical properties of EMC materials obtained are used as inputs for static linear simulation. Package stresses are retrieved from the simulation for relative comparison. The simulation results clearly show that the material degradation due to HTS has significant impact on the package stress level especially at high temperature range, which is critical for packages with stringent reliability requirement in automotive industry.