Soldering (Lead-Free)

Lead-free soldering refers to the use of solder alloys that do not contain lead (Pb) above the RoHS Annex II maximum concentration value of 0.1% (1000 ppm). The transition from tin-lead (SnPb) solders to lead-free solders was one of the most significant manufacturing changes driven by RoHS 1 (2006). The most widely used lead-free solder alloys are SAC (tin-silver-copper) alloys, particularly SAC305 (96.5% Sn, 3% Ag, 0.5% Cu). Lead-free soldering requires higher process temperatures than SnPb soldering (melting point ~220°C for SAC305 vs. ~183°C for SnPb), which has implications for component heat tolerance and PCB design.

Directive 2011/65/EU, Annex II (lead restriction); Annex III exemptions for high-melting temperature solders; IPC standards for lead-free assembly.

Lead-free soldering is now standard across most EEE manufacturing. However, specific Annex III exemptions remain valid for high-melting temperature solders (where lead-free alternatives are not technically feasible) and for certain server, semiconductor, and network infrastructure applications. Manufacturers using lead-bearing solders for exempted applications must document which specific Annex III entry applies. Delegated Directive C(2025)5939 (September 8, 2025) updated exemptions for lead in high-melting temperature solders.