A novel two-step poly CMP to improve dishing and erosion effect on self-aligned floating gate process

A novel two-step poly CMP approach is successfully demonstrated. Experimental results show that the dishing amount was less than 10 nm at the largest pattern of 100 um wide and had no variation in whole patterns, which means local and global planarization are achieved. This result suggests that the developed two-step poly CMP process can be successfully applicable to fabricate the self-aligned floating gate flash memories.