Toxicity, Availability and Extraction

of the Metals used in Lead-Free Solders


Professor Julie M. Schoenung

Chemical Engineering and Materials Science

University of California, Davis USA




To be Presented at:

UC SMART Sponsored Two-Day Workshop on

Pb-free Solder for Electronic, Optical, and MEMS Packaging Manufacturing

September 5-6, 2002

University of California, Los Angeles



There is significant pressure for the US electronics industry to eliminate lead-based solders from their components and assemblies.The driving forces include regulatory activities from abroad, primarily from Europe and Japan, state-level initiatives domestically, and economic incentives to maintain or increase market share through enhanced public perception.These pressures have led to substantial research and development of alternative lead-free alloys, which contain other alloying elements such as antimony, bismuth, copper, indium, silver and tin. This presentation will present our research findings into the environmental impacts of these alternatives during the early stages of the metalís life cycle.Specifically, this presentation will focus on (i) the toxicity and public health effects of each metal, (ii) the availability and supply of raw materials containing each metal, and (iii) the extraction and production processes used to acquire each metal.Lead will be included in the discussion, as it serves as the baseline for comparison.Our results indicate that, from the perspective of being environmentally conscious, lead-free solder alloys present significant environmental challenges and limitations to full-scale substitution.



Acknowledgments:Anna Ku, Dele Ogunseitan, Jean-Daniel Saphores, Andrew Shapiro; UC Irvine and AT&T Foundation for financial support.