DIC on the Thermal Expansion Coefficient Measurements of Palladium at Different Temperature Levels

• Main Authors: Yu-tsung Chu, 朱祐璁
• Other Authors: Chi-Hui Chien
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/njrnea

碩士 === 國立中山大學 === 機械與機電工程學系研究所 === 102 === In traditional IC packaging, wire bonding is typically performed using gold. In recent years, increasing gold prices have motivated the packaging industry actively to develop copper wire bonding technology. Coating copper wire bonding with palladium can prevent oxidation of the copper wire, increase its strength, maintain ball shape after bonding, and reduce production cost. Computers are currently used to perform simulations using the finite element method to solve complex problems. However, basic mechanical parameters of the material must be entered into the relevant program before simulation and analysis can be effectively performed. Some of the literatures provide experimental values of the thermal expansion coefficient of palladium at low temperature, from -243℃ to -3℃,which are used to determine, by extrapolation the thermal expansion coefficient at high temperatures from 20.15℃ to 227℃. However, no experimental results on the thermal expansion coefficient of palladium at high temperatures have been obtained. This investigation measures the thermal expansion coefficient of palladium at various temperature, from 30℃ to 200℃, using digital image correlation. The experimentally obtained thermal expansion coefficient of palladium and its deviation from extrapolated values in the literature increased with temperature. At temperature of 170℃, the deviation was 19.34%, indicating that the data extrapolated from the literature must be revised. Best fitting a combination of experimental data at low temperature in the literature and experimental data herein yields a cubic polynomial which can predict the thermal expansion coefficient of palladium from -243℃ to 200℃.