Study of Solder Spreadability at Different Soldering Conditions Using Factorial Experiments

The solder spreadability on the soldering surfaces is one of the critical parameters for reflow soldering which is used for electronic assembly. Solder spreadability gives us knowledge about wetting, surface tensions, and reliability issues like bridging etc. This article deals with full factorial experiments of solders spreadability of four different surface finishes (passivated copper, electroless nickel immersion gold - ENIG, immersion tin - ImSn and hot air solder levelling - HASL), and five types of solder paste with the following solder alloy composition: Sn62Pb36Ag2, Sn95.5Ag4Cu0.5, Sn96.5Ag3.5, Sn96.5Ag3Cu0.5, Sn42Bi58. Additionally, three different reflow soldering techniques (infra radiation, convection air and vapour phase soldering)were used in the experiment. The use of factorial experiments is a novelty in our approach. Results show that all used materials and solder pastes have good spreadability. The best results were achieved for copper surface finish.