The Polymer Society of Korea

Abstract

In electronic packaging, no-clean solder pastes suffer from reliability issues caused by fine flux residues. Water-soluble solder pastes provide superior cleanability but are vulnerable to moisture absorption under high-humidity conditions, resulting in reduced process stability during reflow. This study aims to introduce functional polymer additives to improve the humidity resistance of water-soluble solder pastes. Prior to additive application, baseline reflow conditions and flux behavior were investigated using a commercial water-soluble solder paste flux from DS Hi-Metal, whose detailed composition was not disclosed. Surface conditions were compared under different reflow atmospheres (air, dry air, and nitrogen), and FT-IR analysis before and after reflow was conducted to examine functional group changes. Based on these investigations, siloxane–polyether functional polymer additives are expected to enhance process reliability under high-humidity conditions.