Challenges of viscoelastic characterization of low TG epoxy based adhesives for automotive applications in DMA and relaxation experiments

Abstract

Microelectronic devices integrate more and more diverse materials in order to miniaturize the packages. Epoxy resins enable smaller electronic devices with promising features [1]. The performance and the reliability of the product are highly dependent on the material behavior of the components and on their interaction under different loading situation. Electrically conductive adhesives are widely used in semiconductor technology. The focus of this work is set on Isotropic Conductive Adhesives (ICA) with a high amount of electrically conductive filler particles. The aim of this work is the material characterization of highly filled epoxy based die attach materials by dynamic mechanical analysis (DMA) and relaxation experiments in order to derive the elastic and a viscoelastic material model in a wide temperature range and the thermo mechanical analysis TMA measurement results to obtain the coefficient of thermal expansion CTE and information about the residual stresses in the adhesive material. A comparison and discussion of measurement and simulation results from FEA with implemented material models obtained using DMA and relaxation experiment will be done. We use as an example to illustrate our method a measurement from two glue samples A and B. The measurement of the epoxy based highly filled die attach material is a challenging topic. We show how to overcome the difficulties in measuring these materials.