Dynamic Test Method of Solder Reflow Performance and Its Application

Dynamic test of solder reflow process by microscope, CCD etal video picture, has been introduced. The whole process of solder reflow is not only observed but also analyzed conveniently by this method. At the same time, deficiencies in the solder paste-tin ball testing were avoided that only the final pattern of the process could be available and its middle process could not be observed. By the dynamic testing of solder reflow process, the effect of preflow time on performance was studied and the performance of solder paste shrinking to a sphere was evaluated. The experiment results showed that there was a limitation of the temperature keeping time during the paste reflowing and the faults would be increased greatly if the time over limitation. Possibility of solder balls, tombstoning and deflection of elements is reduced when the viscosity of solder paste increased and a better reference of solder reflow process was offered by comparison of different solder reflow processes.