Rapid laser-beam reflowing of Pb-free solder foils

Abstract

Different demands are claimed concerning the mechanical, thermal, and electrical characteristics of solders and soldered joints. This is due to new operation fields together with processing temperatures up to 200/spl deg/C. New development and analysis of Pb-free solders with a widespread melting range complies with acute requirements to ensure higher strength and fatigue stability as well as better wetting performance. The aim of the laser-beam processing experiments was to extend the quality of micro soldered joints and metallization systems through grain refining by rapid laser-beam reflow of innovative Pb-free solders. The experimental tests included the structure of the reflowed solder foil, the shear strength and specific diffusion phenomena of soldered joints.