Thermomechanical Behavior of Multilayer Structures in Microelectronics

Linear thermoelastic lamination theory was used to determine the state of residual stresses and warpage in multilayer structures following elevated temperature curing. The inputs necessary are the mechanical and thermal properties of each layer, the stacking sequence of layers, and the irreversible chemical deformation taking place during curing of the polymeric matrix layers. The predictions were verified experimentally with a woven-glass/epoxy material. The basic mechanical and thermal properties and polymerization shrinkage were determined for the unidirectional layer. Subsequently, the warpage was measured for a [0₆/90₆] antisymmetric cross-ply laminate by means of the shadow moire´ method. Experimental results were in good agreement with the theoretical prediction.