Experimental and Theoretical Study of Warpage Behavior for Viscoelastic Three Layer-Laminated Structure by Thermal Load

Abstract

We experimentally examined the warpage behavior of a viscoelastic three-layer laminated structure consisting of steel/epoxy resin/printed board which modeled that of electronic devices caused simply by a series of thermal load from heating to cooling. We also calculated the warpage behavior using the finite element method and a thermo-viscoelastic stress/deformation analysis program based on linear viscoelastic theory which we have developed. Then, those experimental values were compared with those two theoretical values. From our results, the experimental warpage values are in good agreement with the thermo-viscoelastic analysis values, but are not in good agreement with the finite element analysis values. In addition, the warpage behavior of the viscoelastic three-layer laminated structure is influenced not only by the material properties such as glass transition temperature, modulus of longitudinal elasticity, and thermal expansion coefficient which depend on the temperature and flexural rigidity based on the thickness and width of the three-layer laminated structure.