Characterization of methyl-doped silicon oxide film deposited using Flowfill™ chemical vapor deposition technology

Abstract

In this article, methyl-doped silicon oxide films deposited using Flowfill™ chemical vapor deposition (CVD) technology have been chracterized for use in inter-layer dielectrics application. Films with different methyl concentrations were deposited and characterized in order to study the effect of methyl concentration on film properties. Material properties including chemical composition and bonding structure, density, dielectric constant (κ), refractive index, thermal stability, resistance to moisture absorption, leakage current, and hardness were investigated. The films have a κ as low as 2.7 and were found to be thermally stable up to 550 °C. They show excellent resistance to moisture absorption. Low-leakage current and breakdown voltage higher than 3 MV/cm were obtained. Their hardness is lower than silicon oxide deposited using plasma-enhanced CVD but is higher than most polymer and nanoporous low-dielectric constant (low-κ) materials. The chemical mechanical polishing (CMP) characteristics of these films and their stability under plasma treatments were also studied. Film’s CMP removal rate decreases as the methyl concentration in film increases. An atomically smooth surface with root mean square surface roughness <1 nm over a 10×10 μm area was obtained after CMP. This film remains stable under nitrogen (N2) and hydrogen (H2) plasma but is damaged by oxygen (O2) plasma.