Study on Wet Alkaline Chemicals Etching of Hole Dummy Polysilicon in 3d Multi-Layer Structure

Polysilicon, utilized as a dummy material, is an essential component in the fabrication of 3D film stacked memory structures. This study investigates the removal mechanisms of dummy polysilicon using traditional alkaline chemicals, specifically Ammonia DIW Mixture (ADM) and Tetramethylammonium hydroxide (TMAH), within high aspect ratio hole structures. The results clearly demonstrate that TMAH etching agent offers superior uniformity and stability in the removal of dummy polysilicon compared to the ADM solution.