Screening life cycle assessment of silver-based conductive adhesive vs. lead-based solder and plating materials

Abstract

Conductive adhesives are getting growing attention in the electronics industry as they constitute an alternative to lead-free solders and conventional solders. The purpose of the present research is to compare the 10Sn90Pb solder paste to an epoxy based isotropically conductive adhesive (ICA) containing pure silver. The study is done from a life cycle perspective in Japan using input data from literature and the inventory results are evaluated using the Life cycle Impact assessment Method based on Endpoint modeling (LIME) methodology. The findings are that the silver containing adhesive, excluding platings, are superior to the 10Sn90Pb, and that trade-offs exist between 10Sn90Pb and silver-epoxy ICA. For surface platings palladium dominates the results. Overall, the results are dominated by various lead emissions, the silver resource consumption, and the sulfur oxide emissions from palladium production. The most important research limitations are the representativity of the metal production data and end-of-life scenario. The value of the present study is that so far no LIME-based life cycle impact assessment case study comparing 10Sn90Pb solder paste and silver-epoxy ICA including platings has been reported. © 2007 The Japan Institute of Metals.