Through-hole filling characteristics of solderable polymer composites with low melting point alloy fillers

Abstract

In this paper, we describe the development of a novel through-hole filling technique using solderable polymer composites (SPCs) with low-melting-point-alloy (LMPA) fillers. Three types of SPCs with different LMPA concentrations (40, 50 and 60 vol%) were formulated, and through-hole filling tests were conducted under different environmental reflow conditions (atmospheric pressure and decompression conditions). The results indicated that the through-hole filling assemblies showed weak filling characteristics with huge defects under atmospheric pressure reflow conditions because polymer trapped in the hole. On the other hand, the through-hole filling assemblies fabricated under decompression reflow conditions showed favorable filling characteristics and excellent, stable electrical properties due to the effective removal of polymer from the through-hole.