Determination of Equivalent Material Properties of Microsystem Structure for Structural Simulation Analysis

In the microsystem package structure, there are a large number of silicon through holes (TSV), microbumps, substrates, and other structures. The size effect between different structures in the microsystem package is obvious, which brings a lot of difficulties in the simulation analysis and calculation of the structure. Therefore, the TSV/underfill layer is equivalent to a uniform medium by using the idea of structural homogenization. Based on the elastic mechanics method, the equivalent calculation methods of various material parameters (elastic modulus, shear modulus, Poisson's ratio, and thermal expansion coefficient) of cylindrical structures such as TSV are derived in this article. Further, by using the derived results and based on the differential idea, the equivalent calculation process of material parameters after homogenization of microbump/underfill layer with drum ball morphology is given. Compared with the existing methods, the proposed method not only considers the structural and morphological characteristics of the analysis object better, but also has higher calculation efficiency, better consistency, and more reasonable calculation results.