We have studied the wetting behaviors and interfacial reactions of Pb-containing (63Sn-37Pb, 95Pb-5Sn) and Pb-free solders (pure Sn, 96Sn-4Ag, 57Bi-43Sn, 77.2Sn-20In-2.8Ag) on Au foils in order to understand the role of Pb in Pb-based solders. Surface morphology, wetting angle, and interfacial reaction of the solders were studied by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Analysis (EDX). Pb-containing and Pb-free solders (pure Sn, 96Sn-4Ag, 77.2Sn-20In-2.8Ag) showed rough surfaces due to the precipitation of intermetallic compounds on the surface of the solder caps. The eutectic SnBi (57Bi-43Sn) solder, however, showed a smoother surface. The wetting angle of the eutectic SnPb (63Sn-37Pb), pure Sn, 96Sn-4Ag, and 77.2Sn-20In-2.8Ag solders decreased significantly with reflow time, while the eutectic SnBi and 95Pb-5Sn solders showed a much smaller decrease. A large amount of intermetallic compounds was formed throughout the entire region of the solder cap for the eutectic SnPb, 96Sn-4Ag, 95Pb-5Sn, and 77.2Sn-20In-2.8Ag, mainly due to the high solubility of Au in these solders. Slow intermetallic compound growth was observed for the eutectic SnBi solder.
|Number of pages||6|
|Journal||Materials Research Society Symposium - Proceedings|
|State||Published - 1 Dec 1997|
|Event||Proceedings of the 1996 MRS Fall Symposium - Boston, MA, USA|
Duration: 3 Dec 1996 → 5 Dec 1996