DOE RESULTS FOR LEAD-FREE SOLDER PROCESS DEVELOPMENT FOR HARSH ENVIRONMENT CONSIDERATIONS
Authors: Lance A. Brack, Mradul Mehrotra, Emmanuel J. Siméu Company: Raytheon Missile Systems Date Published: 9/24/2006
Abstract: Waste Electric and Electronics Equipment (WEEE) and Restrictions On Hazardous Substance (RoHS) continue to be topics of discussion across the globe at many electronics related conferences, workshops and at many corporations being affected by the European’s initiatives to eliminate lead (Pb) in electronic products. Aerospace and military companies such as Raytheon are exempt from these initiatives, however because of market conditions/forces and lack of critical mass from the aforementioned industry, Raytheon has to become knowledgeable of these processes, evaluate their impact on Raytheon products and be prepared to handle the lead-free challenges. Raytheon Missile Systems (RMS) has provided funding to conduct Pb-Free process development and temperature cycle testing (-55ºC to 125ºC) in order to internally develop the necessary infrastructure. Over the past year, RMS has conducted a feasibility study for process development and characterization of lead-free solders and surface finishes to determine solder process limits using various thermal profiles. Among the surface finishes were tin/silver/copper (SnAgCu) or SAC for BGAs and Sn for leaded and passive devices. This paper will provide an update of the DOE process output relative to SAC and Tin Lead (SnPb) solder comparisons for both convection solder reflow and wave soldering.