Fluorinated amorphous carbon films (a-C:F) with postnitrogen plasma treatments demonstrate the characteristics of interlayer dielectrics, including high resistance to pyrolysis, copper diffusion, and penetration of corrosive species into intermetals. Nitrogen plasma nitridation was performed to passivate a-C:F films against copper diffusion, and to prevent the fluorine contents from penetrating into copper intermetals. These improvements to a-C:F films are potentially applicable to fluorinated dielectrics, such as SiOF.