Mechanical Bonding Properties of Solderable Anisotropic Polymer Composite containing Low-Melting-Point and High-Melting-Point Solder Fillers

Abstract

In this papers, to enhance the mechanical bonding properties of solderable anisotropic polymer composites (SAPCs) containing low-melting-point solder filler only, a new low-melting-point solder and high-melting-point solder mixed filler filled SAPCs (LH-SAPCs) was proposed, and the influence of the high-melting-point solder filler on the conduction path formation and mechanical bonding properties of the LH-SAPC were investigated. Two types of LH-SAPC were synthesized by adding high-melting-point solder within the low-melting-point solder/high-melting-point solder mixed filler at mixing ratios of 0 and 50 vol% (the volume fraction of low-melting-point solder/high-melting-point solder mixed filler in the polymer composite was 20%), and a bonding test was conducted using QFP. The results exhibited that the LH-SAPC containing high-melting-point solder formed a wide and stable conduction path due to the proper selective conduction path formation behavior by the interaction between molten low-melting-point solder and solid-state high-melting-point solder fillers within the polymer composite with low viscosity condition. Furthermore, the mechanical bonding properties of the LH-SAPC joints containing high-melting-point solder were enhanced compared to that of LH-SAPC containing low-melting-point solder only owing to the precipitation hardening and dispersion strengthening effects due to the increase of fine Bi-rich, Cu<sub>6</sub>Sn<sub>5</sub>, and Ag<sub>3</sub>Sn intermetallic compound particles inside the conduction path.