Experimental Investigation of the Formation of Surface Mount Solder Joints

Abstract

As part of a major project to develop a computer-based model to support the product and process design activity for reflow soldered assemblies, it has been found necessary to carry out fundamental investigations of the processes occurring as solder pastes approach and pass the reflow temperature. This paper presents the results and our interpretation of the observed physical phenomena arising from recent high-speed video microscopy studies of the reflow of bulk deposits of solder paste and also of the formation of solder joints during infrared reflow soldering. These studies have provided insights into the physical phenomenology of reflowing solder paste, the interpretation of wetting curves and the mechanisms behind the formation of manufacturing driven defects.

A study on the solderability of QFP outer lead using Nd:YAG laser

“…Additionally, the temperature profile of the IR reflow has a constant zone before soldering temperature. In the case of IR reflow, because of slow heating and constant temperature zone, the paste heated slowly and most of the contained humidity and solvent will evaporate into air [13]. So, laser soldering has more solder balls than IR soldering.…”