摘要
For the advanced 2.5D/3D IC applications, the IMCs suppression and phase stability should be emphasized. With a reduced bonding height of microbumps, the IMCs would occupy a high volume fraction of the joints during the reflow process or operation. A high volume fraction of IMCs and excessive phase transition could induce internal stress and voids, which might be adverse to reliability of interconnection. The novel Cu–26Zn–18Ni/Sn-3.5Ag/Cu–26Zn–18Ni (by weight) microbumps have been fabricated and the considerable inhibition on the IMCs and void formation was investigated. Four kinds of IMC were found in Cu–26Zn–18Ni/Sn-3.5Ag/Cu–26Zn–18Ni microbumps.: (Cu,Ni) 6 (Sn,Zn) 5 , (Cu,Ag) 5 (Sn,Zn) 8 , Ag 3 Sn and (Cu,Ni)Zn. The tough bulk (Cu,Ag) 5 (Sn,Zn) 8 combined with solid solution strengthened and refined (Cu,Ni) 6 (Sn,Zn) 5 grains as well as the void-free microstructure were expected to enhance the reliability of microbumps. The effect of Ag on the formation of tough (Cu,Ag) 5 (Sn,Zn) 8 was also addressed. These findings provided insights into the design of substrate alloy in advanced electronic packaging reliability.