In electronic devices, a crack initi ation and propagation of solder joints lead to failure. A cross-sectional observation and bonding strength test （pull or shear） are often carried out to confirm whether a crack exists or not. However, it has been known that bonding strength of solder joints depends on various factors so that it is unidentified the condition of a crack contributes to the value of strength. In this study, we obtained a 3-dimentional crack structure from X-ray CT data by using deep-learning technique before pull strength test and investigated their correlation.
