Investigation of EOS damage issue induced by failure analysis on back-end test vehicle

Back-end Test Vehicle (BTV) test-key responds to BEOL status effectively. In different process node, it can assist in monitoring real product process inline BEOL status by using fewer process steps. FA is very important steps to confirm the failure Device-Under-Test (DVT) for yield improvement in the BTV validation flow. FA has more and more challenges in advanced process nodes, one of them is EOS damage issue, which issue occurred during the BTV test-key failure analysis in advanced process node. The EOS didn´t come out previous process node and above. This paper will investigate which FA steps on earth happened EOS damage, after that, EOS root cause and solved method was discussed base on experiment result.