Experimental Investigation Of Tensile Strength And Fracture Mode Of Imc Layer In Soder Joints

In microelectronic packaging, solder joints are used not only for chip-level flipchip (FC) packaging technology, but also widely used in board-level, ball grid array(BGA) packaging technology. The reliability of the solder joint has a directly impacton the reliability of the micro-electronic products. The bounding force of solder jointreliability depends largely on the intermetallic compounds which generated by thereaction of solder and pad in the reflow process. Therefore, the study of mechanicalbehaviors of the IMC layer is an important issue for the reliability of solder joints.Tensile specimens with a Cu/IMC/solder/IMC/Cu structure were prepared, andwere treated by0h,72h,168h,288h,500h,1000h isothermal aging processing at150℃. Interface between Cu pad and Sn3.0Ag0.5Cu solder was metallographicobserved, the change of IMC’s morphology, thickness, roughness were measured.Finally, a relationship of the IMC’s thickness and the aging time was derived.Quasi-static tensile tests were conducted on the micro-tester Instron5948, toobtain the tensile strength of specimens in different aging time, and the effects of theaging time, IMC’s thickness and the roughness which had a effect on the interface’stensile strength. It have a conclusion that roughness had significant influence on thetensile strength.Fracture analysis of fractured specimens was conducted by optical microscopyand scanning electron microscopy. Two fracture modes were found, and the fracturingsurface tends to be flat with the aging time increases.In this paper, how the IMC layer’s thickness and roughness change affects themechanical behavior of the IMC layer was researched. and summarizes the fracturemode of the IMC layer interface,Some conclusions of the study will help to further understand how themicro-structure evolution affecting the mechanical behavior of solder joints.