A Room Temperature Chemical Vapor Deposition SiOF Film Formation Technology for the Interlayer in Submicron Multilevel Interconnections

Abstract

A new interlayer dielectric film formation technology for multilevel interconnection by catalytic chemical vapor deposition has been developed. This technique utilizes fluorotriethoxysilane and water vapor as gas source. The films deposited at 25°C have remarkably good properties, such as tightly bonded Si‐O networks with no OH radicals, large density value (2.20 g/cm³), small residual stress (50 MPa), low leakage current, and small dielectric constant (3.7), although the film contains residual fluorine and carbon atoms with , respectively. Based on the film characterization results, we speculate that the reaction sequence for the film deposition is: hydrolysis of fluorotriethoxysilane monomers, formation of siloxane oligomers with reaction by‐product (alcohol), adsorption of the oligomers to the wafer surface, and then polymerization. The electrical conduction mechanism study revealed that the Schottky emission was dominant for the electric conduction through the film. It also has clarified that the deposition film thickness has no dependence on Al wiring widths, and is completely isotropic with no crack or keyhole in the film.