Visco-elastic-plastic properties and constitutive modeling of underfills

Abstract

The thermo-mechanical testing of HYSOL FP4526 underfill, a filled polymer, is reported, including the details of sample preparation and test procedures. Both strain rate and temperature dependence are found for the Young's modulus of the underfill. The constitutive framework proposed for solder alloys (Qian and Liu, 1997) is, for the first time, applied successfully to the thermo-mechanical properties of HYSOL FP4526 in this paper. Excellent agreement between model predictions and experimental data is achieved.