Virtual thermo-mechanical prototyping for high-temperature-application microelectronics

In this paper, an investigation on the reliability issues of the packages for high temperature applications is presented. First, experimental characterizations of aging effect on the packaging materials and the package were carried out. DMA, TMA and TGA were used to measure the moduli, coefficients of thermal expansion (CTE), and the shrinkage induced by the aging process. Construction analysis was performed to examine the aging effect on the microstructure of the aged samples. It is found that aging has significant influence on the rubbery modulus, the glass transition temperature (T_g) and the strength. Oxidation is believed to be one of the main mechanisms for the degradation of the material properties. In order to reduce cost and time-to-market, thermo-mechanical virtual prototyping is applied to investigate effect of aging on the reliability of the high temperature application packages. An aging-dependent elastic model has been established to describe the material property evolution caused by aging. 3D Finite Element models were established to simulate the impact of the aging effect on the stress/strain of the package. Aging-induced shrinkage was also considered in the model, which was applied to the surface layer. The modeling results indicate that the aging of the compounds have a significant impact on the stress/strain status in the package. And the aging-induced shrinkage can not be simply neglected. Further research work on the experimental aspects and improvement of the aging-related material models are needed.