Thermal fatigue reliability design of solder bumps in TSV interposer package based on finite element analysis

The thermal fatigue reliability of solder bumps in TSV interposer package is analyzed by finite element method. The 3D finite element model of TSV interposer package is established in ANSYS software. Anand constitutive model is adopted to describe the viscoplastic behavior of Sn3.0Ag0.5Cu lead-free solder bumps. The influences of material properties and structural geometries on thermal fatigue reliability are evaluated by Taguchi method. The optimized factor combination design for promoting thermal fatigue reliability is obtained and validated by finite element analysis. The finite element modeling results show that the critical solder bump is located at the corner of solder bump array. Both the maximum von Mises stress and accumulated nonlinear strain energy density are located at the top layer elements of the critical solder bump. It is found that the material properties of underfill have the most important influence on thermal fatigue reliability of solder bumps. The higher Modulus and lower CTE improves the thermal fatigue life greatly. It is validated by finite element analysis that the optimized factor combination design can successfully improve the thermal fatigue reliability of solder bumps.