Testing for tunneling opens

A tunneling-open failure mode is proposed and carefully studied. A circuit with a tunneling open could pass at-speed Boolean tests but fail VLV testing or I/sub DDQ/ testing. Theoretical calculations as well as Boolean and I/sub DDQ/ experiments confirm the existence of tunneling opens. The Murphy experimental data show that seven out of nine VLV-only failure circuits can be explained by this failure mode. All these seven circuits survived 366 hours temperature burn-in. Finally, a cost effective screening strategy is proposed.