Soldering & Surface Mount Technology

Purpose – Using two different conceptual approaches to environmental life-cycle assessment, attributional and consequential, the purpose was to test the hypothesis that a typical lead free solder paste Sn95.5Ag3.8Cu0.7 is worse than Sn63Pb37 as far as global environmental impacts are concerned.

Design/methodology/approach – Single index weighting indices within the impact methodology Life cycle Impact Assessment Method based on Endpoint Modelling (LIME) impact methodology, were applied to the flows of three life cycle inventory models and their globally related flows. The LIME results based on three environmental impact categories, i.e. resource consumption, global warming and ozonelayer depletion are presented and discussed.

Findings – The attributional LCA (ALCA) results point towards a larger impact for Sn95.5Ag3.8Cu0.7 than Sn63Pb37 mostly due to the higher Sn and Ag content. This study confirms earlier similar ALCAs. The system expansion for the Consequential LCA (CLCA) did not change this conclusion.

Research limitations/implications – The present study has not included the affected microelectronics packaging parts of electronic products, nor has it included toxic effects as they are local. ALCA was considered to be equal to CLCA for Sn95.5Ag3.8Cu0.7, where no Ag nor Sn recycling was included.

Originality/value – For the first time a global environmental impact assessment of the shift to Pb-free solder paste using the LIME weighting method applied to a CLCA is reported. Environmental life-cycle investigations intended to support decisions of an ecological nature in the microelectronics packaging industry should benefit from the consequential approach.