A NEW ENVIRONMENTALLY BENIGN METHOD FOR LEAD-FREE SOLDER DEFLUXING
Authors: Albert J. Mastrangelo, Susan Chute, Jay Soma, Robe Company: Petroferm Inc. Date Published: 9/24/2006
Abstract: Emerging global environmental regulations, including the approaching enactment of the Restriction of Hazardous Substances (RoHS) Directive, are forcing manufactures to reexamine cleaning processes used in electronics assembly. The demand for more vigorous chemistries to remove post reflow flux residues is increasing. This is due to the higher activity level in lead-free soldering fluxes, the effect of higher reflow temperatures on board cosmetics, and an increase in rework of lead-free assemblies. Lead-free solder paste formulations are proving to be much more of a challenge to clean with currently available azeotropic vapor degreasing chemistries than the previous generations of lead containing pastes. Recent testing of multiple cleaning technologies has indicated that the co-solvent degreasing process is capable of cleaning these new fluxing systems. In addition to being an effective cleaning process, the cosolvent technology is both environmentally friendly and cost effective. This study examines the effectiveness of the co-solvent process using a variety of cleaning chemistry types and a large number of both lead-free and lead alloy eutectic solder paste formulations from multiple leading suppliers.