Researchon Mechanical Behavior Of Through Silicon Via Of 2.5d Interposer

In this paper, the mechanical behavior of the 2.5D interposer was investigated under the thermodynamic loading of -65 similar to 150 degrees C temperaturecycle and 150 degrees C high temperature storage. It was found that cracks first appeared at the interface between the copper wiring layer and the passivation layer after 500 temperature cycles. With the increasement of temperature cycles, the upper cracks propagated laterally and some cracks converged, causing the surface passivation layer to peel off. Finally, the stress resulted from the expansion of Cu pillar in the through-silicon via (TSV)during the temperature cycling caused the separation of the wiring layer and the passivation layer, which is the main reason for the formation of crack initiation, due to the fact that the coefficient of the thermal expansion(CTE) of copper is larger than that of silicon. In addition, the effects of copper wiring and TSV pitch on stress and cracks were also investigated in this paper.