Low-cycle fatigue testing and thermal fatigue life prediction of electroplated copper thin film for through hole via

Abstract

A new fatigue test method was proposed for low-cycle fatigue lives of electroplated copper thin films for the through hole (TH) in a printed wiring board. And the low-cycle fatigue lives were investigated according to the proposed method. Furthermore, thermal stress analysis of the TH with the finite element method was performed to predict thermal fatigue life of the TH based on Manson-Coffin law for electroplated copper thin films obtained from the low-cycle fatigue test. Low-cycle fatigue damage in the electroplated copper thin film was occurring in the grain boundaries and the damage mechanism was found same as that for thermal fatigue damage in TH in the printed wiring board. And the fatigue life of TH predicted from the Manson-Coffin law at the maximum temperature of thermal fatigue test was good agreement with the thermal fatigue life obtained from the experimental result of thermal fatigue test.