Microstructure, solderability, and growth of intermetallic compounds of Sn-Ag-Cu-RE lead-free solder alloys
- 337 Downloads
The near-eutectic Sn-3.5 wt.% Ag-0.7 wt.% Cu (Sn-3.5Ag-0.7Cu) alloy was doped with rare earth (RE) elements of primarily Ce and La of 0.05–0.25 wt.% to form Sn-3.5Ag-0.7Cu-xRE solder alloys. The aim of this research was to investigate the effect of the addition of RE elements on the microstructure and solderability of this alloy. Sn-3.5Ag-0.7Cu-xRE solders were soldered on copper coupons. The thickness of the intermetallic layer (IML) formed between the solder and Cu substrate just after soldering, as well as after thermal aging at 170°C up to 1000 h, was investigated. It was found that, due to the addition of the RE elements, the size of the Sn grains was reduced. In particular, the addition of 0.1wt.%RE to the Sn-3.5Ag-0.7Cu solder improved the wetting behavior. Besides, the IML growth during thermal aging was inhibited.
Key wordsLead-free solder rare earth (RE) elements solderability test intermetallic layer
Unable to display preview. Download preview PDF.
- 1.J. Glazer, J. Electron. Mater. 23, 693 (1994).Google Scholar
- 2.International Printed Circuit Association Solder Products Value Council, “White Paper: IPC-SPVC-WP-006 Round Robin Testing and Analysis, Lead Free Alloys: Tin, Silver, Copper,” 12 August 2003.Google Scholar
- 5.C.M.L. Wu, D.Q. Yu, C.M.T. Law, and L. Wang, J. Mater. Res. 17, 3146 (2002).Google Scholar
- 7.D.R. Flanders, E.G. Jacobs, and R.F. Pinizzotto, J. Electron. Mater. 26, 883 (1997).Google Scholar