A Novel Continuous Plasma Etch with Optimized Algorithms for Yield Improvement and High Production Throughput in NOR Memory

In NOR memory device, there was massive yield loss of more than 10% caused by missing contacts in a multi-layer resist (MLR) contact etch process. We have developed a novel continuous plasma process (CPP) combined with new endpoint algorithms to fix the missing contact issue. We present the investigation of root cause using etch movies at the hardmask (HM) step. Later, we show results from applying the novel CPP combined with new endpoint algorithms at two HM steps. This approach significantly improved process margin by eliminating missing contact issue and also reduced raw process time (RPT) by 4.8% for better production throughput.