Numerical simulation study on thermomechanical reliability of annealed TSV-Cu structure

Pre-annealing is an essential process in TSV fabrication, which can relieve internal stress of TSV-Cu and change its mechanical properties. In the subsequent process, the TSV-Cu structure has to undergo thermal load, and thermal deformation and thermal stress are unavoidable due to thermal mismatch of interface materials. Excessive thermal stress threatens interface crack and solder joint reliability of TSV-Cu structure. In this paper, the stress and energy character of interfacial crack and solder joint of TSV-Cu structures under thermal loads of 25-420-25°C have been investigated by FEM calculation, and the thermomechanical reliability of different annealed TSV-Cu structures also has been studied. In comparison, the pre-annealing process at 400°C+120 min is relatively the most favorable for the thermomechanical reliability of the TSV-Cu structure.