The FIB (Focus Ion Beam) Construction analysis is widely used in FA field, such as evaluating process limitations, debugging, and root cause demonstration. In this paper, we describe the reliability check method of the via by using FIB. Based on the electromigration (EM) test of the vias, the reliability check method of the vias is studied through the influence of void area ratio in the via on the EM lifetime of the via. The results showed that under different operating conditions, the same void area ratio has almost the same influence on the EM lifetime, and with the increase of void area ratio in the via, the EM lifetime of the via decreases, when the lifetime decreases by 20%, the corresponding void area ratio is about 12%, which can be used as the check criteria of the via.