METHOD FOR EVALUATING SOLDER JOINT PORTION

摘要

A method for evaluating a solder joint portion by means of which a part and a substrate are joined to each other includes a preparation process for preparing the substrate including the solder joint portion, a thermal shock process for applying thermal shock to the solder joint portion multiple times, and an evaluation process for obtaining a change of a crystal grain size in the solder joint portion caused by the application of the thermal shock so as to evaluate a lifespan of the solder joint portion based on the change of the crystal grain size obtained.