Interfacial Bonding Behavior between Sn-Ag-Cu Series Lead-free Solders and Cu/Ni-P/Au Substrate

• Main Authors: Po-Cheng Shih, 施伯錚
• Other Authors: Kwang-Lung Lin
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/62788210599217926763

碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 91 === Abstract The interfacial bonding behavior between Sn-Ag-Cu series lead-free solders and Cu/Ni-P/Au substrates were investigated in this work, which includes the shear strength measurement and interfacial reaction. The solder compositions are Sn-3.2Ag-0.5Cu and Sn-3.5Ag-0.5Cu-0.07Ni- 0.01Ge (in wt%). The shear strength was investigated with a shear strength tester and the influences of thermal aging time and the composition of the solder on the shear strength were also studied. Furthermore, the possible factors of affecting interfacial bonding behavior were discussed relating to interfacial reaction. The shear strength test data revealed that the average value of shear strength of Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge solder is slightly higher than that of Sn-3.2Ag-0.5Cu solder after reflowed. Hence the addition of Ni, Ge can enhance the shear strength of solder ball attachment. On the other hand, as thermal aging time increased, the shear strength was decreased, and the average shear strength in the two solder systems are quite close. Therefore, the influences of the addition of Ni, Ge on shear strength seemed not evident after thermal aging treatment. The ductile fracture surface occurred in the solder after reflow and aging. The results of interfacial analysis revealed that there are two intermetallic compounds formed at the interface. One is pyramid-shape (Cu, Ni)6Sn5 and the other is (Ni, Cu)3Sn4. Moreover, the Ag3Sn IMC of the particle and plate shapes can be observed in the solder alloy. After long-term thermal aging, (Ni, Cu)3Sn4 and Ag3Sn coarsened but (Cu, Ni)6Sn5 not, meanwhile the composition of IMCs almost kept constant and no other new IMC formed at the interface or in the solder alloy.