Oval-Shaped OP-Layer Hole Etching: Shape Deformation, Local Arcing, and Hole Bridging Improvements

The challenges of oval-shaped silicon dioxide and polysilicon (OP)-layer hole etching, including shape deformation, local arcing, and adjacent hole bridging are reported. We explore the shape deformation evolution step by step and point out that wiggling of the organic mask is the most critical factor to enhance the occurrence of shape deformation. Further, the local arcing induced profile damage during hole-patterned etching could be eliminated by stacking specific capping materials on the top of OP layers. A DOE of the etch process demonstrates the ability to solve the adjacent hole bridging issue.