环氧/Cu界面混合分层断裂研究

Study on the Mixed-Mode Fracture of the Epoxy-Cu Interface

高密度塑封器件不同材料间分层断裂常导致器件失效,且界面通常为正应力作用下的张开型(模式I)断裂和切应力作用下的滑开型(模式II)断裂的混合模式。环氧塑封料和Cu引线框架之间热失配较大,在热、力学载荷作用下,环氧/铜界面易发生界面分层断裂。设计了一种双相材料样品和一种可以对样品施加不同角度拉力的装置,用于测试环氧/铜界面混合断裂参数。通过弹性断裂力学分析,基于实验结果可以得到界面断裂能量释放率和混合断裂相位角。该方法可以应用于电子封装中其他界面断裂参数的表征。

In high density plastic packaging devices,delamina tion between differe nt materials often leads to device failure.The interfacial fracture exhibits m i xed-mode case which includes opening mode（mode-I） fracture with normal stress a nd sliding mode（mode-II） fracture with shear stress.The coefficient of trermal expansion（CTE） mismatch between e poxy mold compound and copper lead frame is large.The interfacial fracture is p rone to take place at interface of epoxy/Cu under thermal and mechanical loading s.A bi-material sample and a new apparatus to characterize the mixed-mode fr act ure were designed to test the mixed-mode fracture parameters of epoxy/Cu interf a ce.The energy release rate of interfacial fracture and mode mixity were obtain e d based on the experimental results by the elastic fracture analysis.The metho d can be applied for fracture characterization of other interfaces in electronic packaging.