Fluorinated Amorphous Carbon Thin Films for Multilevel Interconnections of Integrated Circuits.

Abstract

Fluorinated amorphous carbon thin films (a-C:F) for low-dielectric-constant interlayer dielectrics were deposited by helicon-wave plasma-enhanced chemical vapor deposition using fluorocarbon compounds as a source material. The a-C:F films could be grown from C4F8 at a high deposition rate (above 400nm/min) and they were thermally stable up to 300°C. The addition of bias power to the substrate made it possible to completely fill gaps in the wiring (space 0.35μm, height 0.65μm) with the a-C:F film. To protect the a-C:F film during further processing, we deposited a SiO2 film to add mechanical strength and resistance to the oxygen plasma used to remove resist materials. The adhesion between the a-C:F and SiO2 films was dramatically improved by inserting an adhesion promoter consisting of a-C:H and Si-rich SiO2.