PROCESS AND MATERIAL CHARACTERIZATION FOR LEAD-FREE TIN-COPPER SOLDER ALLOY
Author: RonaldE. Pratt Company: IEC Electronics Corp. Date Published: 8/23/1998
Surface Mount International
Abstract: The eutectic tin-copper alloy, 99.3Sn-O.7Cu, was characterized and evaluated as a potential lead-free solder candidate. Lead-tie, mixed surface mount and through-hole assemblies that were manufactured at three different sites were analyzed after O, 2000, 4000 and 6000 thermal cycles from O“C to 100 “C. The results for the tin-copper solder joints were compared to those obtained for eutectic tin-lead solder joints. The external visual appearance, void content, wetting, component condition, microstructure, intermetallic growth, crack growth and strength for the lead-free solder joints were assessed at each stage of thermal cycling. It is concluded that the eutectic tin-copper alloy is a viable alternative to tin-lead solder for some applications and that possible enhancements to the microstructure of the solder joints could further expand its range of applications.