FE-simulation for polymeric packaging materials

Finite element (FE)-simulations are a useful tool to evaluate the thermo-mechanical behaviour of electronic packages. However, the use of the FE-method generates special difficulties, in particular concerning the proper constitutive modeling of materials used in the assembly. One more general problem in the numerical investigations of encapsulated silicon chips is the occurrence of interfaces between the dissimilar materials. Due to the assumption of sharp interface edges and interface crack tips stress singularities arise which might be accounted for only approximately in the FE-calculation. The paper intends to show solutions of these simulation difficulties. The complex material behaviour is discussed for different filled epoxy materials, especially with regard to the influence of filler content. A new solution method of the interfacial edge problem is shortly introduced. As an example, the pull strength test is used and the asymptotic solution of an interface edge is presented.