Experimental optimization of process parameters for diode laser soldering of BGA

It has been shown that diode laser soldering is suitable for electronic packaging especially for the rework of ball grid array (BGA) chips, because laser soldering technique for BGA packaging has several distinct advantages over conventional methods. In this study, we build an experimental prototype laser soldering workstation and have some researches on the laser bumping process. We first summarize researches and applications of laser soldering in electronics assembly in recent years. Then our diode laser soldering system is introduced. In order to study the influence of different parameters for obtaining a good solder Joint, some experiments are carried out with a continuous-wave (CW) diode laser rating up to 2.4 watts on the soldering process. We study some key parameters including laser power, irradiation time, reflow height, the amount of flux and misalignment. Experimental results are compared and analyzed. In the end, optimized process parameters are given as a conclusion.