Study of Voids Inside Solder Joints Based on SAC305 Solder Paste with Different Properties

Voids inside solder joints are empty spaces which can cause reliability issues. Solder joints with voids are weaker from a mechanical point of view. Additionally, the soled joints with voids are worse from the point of thermal and electrical properties. This article deals with voids inside solder joint prepared with Sn96,5Ag3Cu0,5 solder paste with different properties from the point offlux type and size of solder alloy powder. The aim of this work is to evaluate the influence offlux and particles size on the voids formation. Preparation of solderjoints was done at the same process conditions for all samples. Solderjoints were analysed via X}-ray with following image analyses of voids. The results show that the less aggressive flux caused slightly higher voids formation from the point of the average surface area of voids at the solderingpad. Additionally, the results show that the slightly higher voids formation appears in case of solder paste with smaller solder alloy particles.