Toward defects-free in lead-free micro-soldering

Many works have been continued to replace Sn-Pb solder alloys by lead-free solder. The lead-free solders to be used in electronics assembly should be compatible for micro-soldering that means the alloys should have adequate melting temperature range and excellent wettability. No lead-free solders has superior wettability to Sn-Pb, therefore, to secure sound joints without defects is important not only from the reliability but also from the environmental aspects, because the sound joints usually offers long life, high reliability and repair free. This work aimed to make a strategy for obtaining defects-free joints in micro-soldering with lead-free solder from the environmental conscious view paint. Especially, the work:focused on? the appropriate selection of lead-free solders and soldering atmosphere to reduce soldering defects.