Part 3: Specifying Base Materials for SMT Circuit Boards

摘要

By now, most companies supplying electronics destined for the world market are aware of the EU's RoHS Directive. The sale of electronic equipment containing more than the established level of lead alloy, cadmium, mercury, hexavalent chromium and polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) flame retardants used in plastics and circuit boards will not be allowed in Europe. Although the effective date for RoHS compliance is July 1, 2006, many companies have already moved to adapt solder processes that use lead-free alloy compositions. The lead-free alloy composition finding favor for soldering on most commercial applications is tin, with a small percentage (by weight) of silver and less than 1% of copper.