Electroless plating copper cones on leadframe to improve the adhesion with epoxy molding compound
A simple method to increase the adhesion strength between leadframe and epoxy molding compound (EMC) was reported in this paper.Cone-structured copper film was deposited on copper-based leadframe sheets by electroless plating.SEM observation of the as-prepared film indicates that cone size distinctly depends on plating time.Adhesion strength between EMC and cone-coated leadframe was measured by button shear test (BST).Results show that when deposition time t≤120s,the adhesion strength increases rapidly with the growth of copper cones,when t >120s,although cones keep growing,the adhesion strength tends to level off.Average adhesion strength reaches maximum value of 33.80(±1.74) MPa,increased by 87% (57%~124%) when substrate was plated for 600s,compared with that of conventional leadframe.By observing leadframe side of fracture surface after destructive button shear test,two failure modes were proposed: failure at interface and inside EMC.It is assumed that the copper nano-cones structure could effectively increase the contact area of EMC and leadframe,which leads to mechanical interlocking.Such micro-nano structure and its unique property are expected to be applied in the practical industry.
Wenjing Zhang Qin Lu Tao Hang Ming Li Dali Mao
State Key Laboratory of Metal Matrix Composites,Key Laboratory for Thin Film and Microfabrication Te Research Institute for Science and Engineering,Waseda University,3-4-1 Okubo,Shinjuku,Tokyo 169-8555
国际会议
桂林
英文
259-263
2012-08-13（万方平台首次上网日期，不代表论文的发表时间）