Macro- and Microscopic DMA measurements - Complementary techniques to determine viscoelastic material properties of packaging polymers

The application of virtual evaluation tools based on the Finite Element Method (FEM) is already widespread in the field of electronics. To predict the lifetime and reliability of microelectronic devices as well as the stress evolution for certain application conditions, fully parametrized finite element studies are utilized. At the assembly level, the geometries and material properties of these models are required to be provided as very complex and predominantly non-linear data. Thus, the predictive power of these models rely on the precisely measured thermo-mechanical properties of the involved materials, for instance the viscoelastic behavior of polymers used in underfillers, PCBs, adhesives, or mold layers. To that, this study focusses on the viscoelastic behavior and its characterization techniques. It is always challenging to determine the relevant viscoelastic properties on product-identical size ranges and specimens. To address this challenge, in this paper, macroscopic and microscopic variants of the Dynamical Mechanical Analysis (DMA) technique are applied to identical, IC product-relevant polymer samples to compare the results of both approaches as well as highlight their corresponding strengths. To directly compare the two DMA techniques, they are both applied to identical dog bone samples, prepared for the macroscopic DMA.