Optimization of reflow soldering process for the surface mounted assembly

摘要

The effect of Cu-Sn intermetallic compounds (IMC) and porosity on the fatigue failure of solder joint has been studied by the fatigue testing. The samples consist of leadless ceramic chip carriers (LCCC) soldered onto FR-4 printed circuit boards (PCB), and are prepared by conventional surface mount technology (SMT) reflow soldering using a 63Sn-37Pb solder paste with metal content of 90percent. The specimens, with various IMC thicknesses and pores area fraction obtained by controllign the soldering time, are subjected to thermal shock between -45 deg C and 135 deg C with a frequency of two cyclic shear fatigue test controlled by the displacement until failure.