Methods of depositing smooth and conformal ashable hard mask films

摘要

Provided are plasma enhanced chemical vapor deposition methods of depositing smooth and conformal ashable hard mask films on substrates containing raised or recessed features. The methods involve using precursors having relatively high C:H ratios, such as acetylene (C:H ratio of 1), and plasmas having low ion energies and fluxes. According to various embodiments, the methods involve depositing smooth ashable hard mask films using high frequency radio frequency-generated plasmas with no low frequency component and/or relatively high pressures (e.g., 2-5 Torr). Also provided are methods of depositing ashable hard mask films having good selectivity and improved side wall coverage and roughness. The methods involve depositing a first ashable hard mask film on a substrate having a feature using a process optimized for selectivity and/or optical properties and then depositing a smoothing layer on the first ashable hard mask film using an HF-only process.