A Constitutive Model of Polyimide Films and Its Integration with Finite Eleement Analysis for Residual Stress Prediction in Thin Film Interconnects

摘要

When lainated structures such as thin film interconnects and high density printed wiring board ware subjected to thermal loads during the manufacturing process, stresses can be produced at the interfaces due to the coefficient of thermal expansion mismatch between heterogeneous materials,. These stresses mah cuase delamination and peeling of the films and they may also affect overall reliability of thin film interconnects. At the same time, the stress state in the structure can change during manufacturing processes due to changes of boundary and lading conditions, more importantly, due to viscoelastic properties of polymers used in the structures. In this study, experiments, were conducted to obtain the viscoelastic properties of polyimide films. A constitutive equation was proposed to describe the visoelastic relations. Further, a process modeling approach was ued to monitor thermally induced stress evolution during.