Process Optimization of Amorphous Carbon Hard Mask in Advanced 3D-NAND Flash Memory Applications

Amorphous carbon hard mask (ACHM) films are widely used as etching masks in 3D-NAND flash memory, which has put forward higher requirements the film deposition rate, transparency, uniformity, and selective etching. In this work, ACHM processing is engineered optimized by comparatively studying acetylene (C2H2) propylene (C3H6) sources at different temperatures of 300 °C, 350 °C 400 °C. By increasing temperature, non-uniformity, dry etch rate improved penalty a slightly increased extinction coefficient film, due to lower incorporation hydrocarbon reactants absorbed into temperatures. However, Fourier transformation infrared (FTIR) spectrum intensity decreased with increase temperature. The achieved using C3H6 source deposited best ratio values also 10.9 9.5 for SiO2 SiN, respectively. These experimental results can be very promising advancement process applications.