Simulation driven design of novel integrated circuits - Part 2: Constitutive material modeling of thermosets

This paper presents the comparison of the simulation capabilities of material behaviors based on the linear viscoelastic (LVE) model and non-linear viscoelastic (NLVE) model for a commercially available molding compound. Both modeling approaches do consider the effect of time and temperature dependency. However, it is found that the LVE modeling technique is not capable of reproducing the large strain, highly non-linear mechanical behavior of the tested thermosets. In order to model this highly non-linear behavior quantitatively, the Bergstrom-Boyce (BB), a non-linear hyperviscoelastic model, is used. When the NLVE model is used to describe the thermo-mechanical behavior of the material, significant improvement in the prediction of time and temperature dependent behavior, as well as in the strain dependent relaxation is achieved. In order to validate the accuracy of BB model, three point bending test and cyclic tensile tests with relaxation segments during loading and unloading to zero, which are not previously used for the calibration of the model, are used. It is also shown and discussed that the proposed methodology can be successfully used in the simulation driven design process in which development of the ECU is supported by quantitative numerical simulation methods.