Characterization of adhesives for microelectronic industry in DMA and relaxation experiments for interfacial fracture toughness characterization — Difficulties and solution

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 attaches materials by dynamic mechanical analysis (DMA) and relaxation experiments in order to derive elastic and viscoelastic material models in a wide temperature range. 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. Critical interface fracture data, which include the Critical (Strain) Energy Release Rate G_c(Ψ) as a function of temperature, humidity or aging, are crucially needed in microelectronic industry for failure modeling, lifetime prediction and design evaluation associated with reliability [1], but they are rarely given in literature. Therefore fast measurement methods are needed [2, 3]. This work shows a measurement method of the critical fracture mechanic properties with the micro Mixed Mode Tester (μMMT) [2] on samples cut from real products and their numerical evaluation using linear elastic fracture mechanics and cohesive zone modeling.