Evaluation of Stress Induced by Plasma Assisted ALD SiN Film

Abstract

Stresses characteristic induced by silicon nitride thin film formed using plasma assisted atomic layer deposition were investigated. SiN films were deposited using batch-type ALD equipment. Stresses were evaluated by UV-Raman spectroscopy, and SiN densities and chemical bonding states were evaluated by X-ray reflectometry and hard X-ray photoelectron spectroscopy, respectively. The stresses induced by SiN films were influenced by the film density and chemical bonding states. It could be controlled by optimization of process temperature. In addition, thermal stability and in-plane fluctuation of stress were also discussed. It was indicated that P-ALD technique has high in-plane uniformity of stress and higher stress comparing with conventional thermal ALD.