| Summary: | 碩士 === 中華大學 === 機械與航太工程研究所 === 95 === Due to the high speed and high I/O count for semiconductor package requirements, thousands of soldered interconnection are indispensable, and this situation renders the traditional finite element method (FEM) analysis a formidable challenge. This thesis presents an FEM submodeling technique with simplified soldered interconnections for investigating the reliability of the semiconductor package. For the submodeling technique, a global model with two equivalent layers was created to represent the soldered bump encapsulating the underfill and soldered ball. Once the global model is solved, the critical small-scale region, i.e., the soldered interconnection, which is called the submodel, is reconsidered as another finite element model. The submodel is then used to solve these specified displacement boundary conditions, which are interpolated from the global model, together with external loads. Two particular flip chip ball grid array (FCBGA) packages companied with experiment results were considered to illustrate the analytical procedures. All solder used was eutectic (63Sn-37Pb) material, and nonlinear behavior using a bilinear elastic-plastic with the hyperbolic Sine creep equation was considered during three thermal cyclic loadings which ranged from 0 to 100 ºC. The predicted lifespan was used in the modified Coffin-Manson’s law. According to the FEM results, the predicted life of the soldered balls were agreed with experiment results well. However the soldered joints life provided more conservative than that of experiment. Due to uncertainty material property of substrate, it is suggested that modified higher young’s modulus of the substrate is able to reach the desired life prediction for soldered joints. One concluded that the methodology in this thesis provides an efficient FEM for evaluating FCBGA package life reliability.
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