Abstract
The residual stress of epoxy resin for IC plastic packages generated in the curing process as well as in the cooling process is studied both analytically and experimentally. The property of thermal expansion in the temperature history and the viscoelastic properties at various temperature conditions are measured by the thermal test method and the creep test, respectively. The adhesive strength of the resin is determined by subjecting tubular adhesive-bonded butt joints to axial and torsional load. With these mechanical properties, the residual stress development is investigated using a 4-parameter viscoelastic model with a thermal shrinkage element. The residual stress is analyzed by the finite element method (FEM) for consistency with a model of resin block which contains a metal plate, and the strength of the model is evaluated for residual stress. The analytical results show a tendency similar to experimental results and the critical position indicated by the residual stress is found to occur at the corner of the buried metal plate.
