Study on reliability of ultrathin device embedded in organic substrate under drop impact loading using stresses monitor and simulation

摘要

Reliability of the embedded ultrathin device in the organic substrate packaging is one of major concerns during its applications. In this paper, drop impact tests were conducted to the embedded ultrathin stress sensor chip in the organic substrate. Stresses were monitored with the embedded stress sensor chip based on silicon piezoresistive effects. Dynamic explicit finite element model with the input-G method was built up to investigate the stress and strain behaviors of the embedded chip and solder bump. The drop impact simulation model was validated by the experimental stresses monitoring results. It indicated that the discrepancy of the normal stress σ11 at the center of embedded stress sensor chip from experimental and numerical simulation results is within 10%. Based on the validated model, the effects of material properties and structural parameters on the stress and strain responses were studied by the numerical simulation. The maximum normal stress σ11 at the embedded sensor chip and the peeling stress σ33 of the solder bump were selected as the indexes for the comparisons and optimizations. The experimental and numerical simulation efforts can provide design guidelines for the embedded ultrathin chip in the organic substrate packaging.