The Effect of Pd and Cu in the Intermetallic Growth of Alloy Au Wire
Authors: Chang, Hen-So; Hsieh, Ker-Chang; Martens, Theo; Yang, Albert
Source: Journal of Electronic Materials, Volume 32, Number 11, 1 November 2003 , pp. 1182-1187(6)
Abstract:This is the new wire evaluation work for the reliability of the wire-bonding process. There is a trend for the plastic integrated-circuit package to function at higher junction temperature with thinner wire. New alloy Au wires have been developed to meet the reliability requirements. Two types of alloy Au wires, Au-Pd and Au-Cu, were evaluated in this study. These samples were aged between 155°C and 205°C under air from 0 h to 3,000 h. According to this study, the phase-formation sequence of Au2Al, Au5Al2, and Au4Al intermetallic is similar to the pure Au wire. There is a Pd-rich layer working as a diffusion barrier to slow down the growth rate of intermetallic phases in the Au-Pd wire. The Au-Cu wire also slowed down the growth rate with a different mechanism. Both wires have better reliability based on the microstructure examination. The reliability test results show longer working life at higher temperatures in comparison with the regular Au wire.
Document Type: Research Article
Publication date: November 1, 2003