Released of Latent Heat from Solder Joints to Surrounding During Solidification of Solder Alloy - Experimental Study

The thermal behavior of solder alloys during melting and solidification is important from point of many aspects. It has influence on formation of joint structure together with intermetallic compounds, reliability issues like tombstoning effect or warpage effect, dimensional changes of components and printed circuit board etc. This article deals with influence of released latent heat from solder joints on the surrounding temperature. Printed circuit boards with soldering pads designed side by side in the matrix and solder paste based on SAC387 solder alloy particles was used in experimental study. The influence of increased number of solder joints in a defined area was examined. The temperature profiles were measured below soldering pads during reflow soldering to find the thermal influences. The results show that released latent heat from solder joint has influence on surrounding temperature and it can delay the solidification of neighbor joint.