Equipment for evaluating the wettability of solder paste has been developed using a laser displacement method. Using the equipment, the descent behavior of an electronic part in reflow soldering can be measured with a laser displacement meter. From the measured height displacement curve, the wetting time and spread rate of the solder paste onto the electrodes of an electronic part and a substrate can be investigated. The developed equipment can detect the difference in the wettability of solder paste which depends on the solder paste type, the electrode type, and the degradation of the solder paste over time.
