ARC induced gate oxide breakdown during plasma etching process

In this paper, an are induced gate oxide breakdown during a plasma etching process is observed and its mechanism is analyzed. The gate oxide under a polyl layer is broken during the poly4 etching process and the poly4 layer is 0.8 mu m higher than the gate (polyl) layer. Broken gate oxide points are found scattered around an are occurrence point where an excessively high electric field is generated. Pattern deterioration, which is caused by heavy ion bombardment when an are occurs, has been observed on the are occurrence point and is the sign of low yield. It is found that any are occurrence can cause dies to fail by breaking the gate oxide, even if the deteriorated pattern area is not on active circuits.