On the Kinetics and Mechanism of IMC Growth and Electrified Tensile Intergranular Fracture of Fine Silver Alloy Wires

• Main Authors: Hao-WenHsueh, 薛皓文
• Other Authors: Truan-Sheng Lui
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/j999mp

博士 === 國立成功大學 === 材料科學及工程學系 === 105 === The growth kinetics of intermetallic compound (IMC) of the Ag alloy wires and Al Pad was discussed, and the damage of excessive current density were investigated by electrified test and the dynamic current tensile (DCT) test. Observations on the Ag-8Au-3Pd wires after high temperature storage (HTS) test indicated that the main IMC between Ag alloy wires and Al Pads were Ag2Al (hexagonal), and the main diffused routes were Ag and Al diffusing into each other. Because a Pd-rich phase as a diffusing barrier of Al was existed in the 200 nm thin layer at the top of the IMC, and the Kirkendall voids appeared upper the IMC. The effects of excessive current density on the Ag-8Au-3Pd wires were investigated by electrified test. The grain boundary were reduced and the electrical resistance were decreased by joule’s heat, and the bamboo grains were formed gradually in current stressing. The DCT test were employed to measure the tensile properties during current stressing. Both the elongation and tensile strength of the wires decreased in the DCT test, particularly the Ag-based wires. The voids and cracks were generated by electromigration and were propagated by strain applied. Therefore, the weakened grain boundary was the main cause of intergranular fracture of the Ag-based wires. Overall, compared to the Cu-based wires, electromigration occurred more easily in the Ag-based wires; therefore, the relationship in electrical current and the change in materials should be noticed to avoid the failures happened.