Analysis of reversed depth micro-loading based on pulsed plasma

Depth Micro-loading control is being generally concerned for the latest semiconductor manufacturing technology during plasma etching, e.g. 14nm CMOS and 3D NAND device etch process. Most current leakage between two adjacent devices can be optimized by changing depth micro-loading. In this paper, a silicon etching method is developed at NAURA etch tool by using CHF3 as the main etch gas under a pulsed plasma. It shows a widely controllable tuning window for depth micro-loading. Normal depth micro-loading can be eliminated or reversed. The trend is shown that the depth micro-loading decreases with the ratio of CHF3/HBr increase.