Publication Date:
2012-08-16
Description:
A uniform layer of the Cu 5 Zn 8 phase is formed at the Sn-9 wt pct Zn (Sn-9Zn)/Cu interface after reflow at 503 K (230 °C) but fractures very severely during subsequent solid-state aging at 443 K (170 °C). Such a severe fracture of an interfacial intermetallic compound deteriorates the integrity of joint interface and leads to excessive atomic interdiffusion as well as intermetallic compound growth. In the current study, it was observed that by inserting an electroless palladium (Pd) layer at the Sn-9Zn/Cu interface, a Pd 2 Zn 9 phase is formed between Cu 5 Zn 8 and Sn-9Zn solders. This Pd 2 Zn 9 phase exhibits higher microstructural stability at the interface during solid-state aging and effectively retards the fracture of the Cu 5 Zn 8 phase. The integrity of the Sn-9Zn/Cu interface is improved remarkably. Mechanical tests reveal that the shear strength of the Sn-9Zn/Cu joint is enhanced by inserting an electroless Pd layer at the interface. Content Type Journal Article Pages 1-6 DOI 10.1007/s11661-012-1377-0 Authors Po-Hsun Lee, Department of Chemical Engineering, National Chung-Hsing University, Taichung, 402 Taiwan R.O.C. Chi-Pu Lin, Department of Chemical Engineering, National Chung-Hsing University, Taichung, 402 Taiwan R.O.C. Chih-Ming Chen, Department of Chemical Engineering, National Chung-Hsing University, Taichung, 402 Taiwan R.O.C. Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623
Electronic ISSN:
1543-1940
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
