Patent ID: 7132171

Claim:
A method of forming a low dielectric constant insulating film, comprising the steps of: (a) forming a non-porous insulating film consisting essentially of said insulating film containing Si—CH n (n=1, 2, 3) bonds in a Si—O—Si or other Si—O skeleton, on a substrate; (b) irradiating said insulating film with ultraviolet light in an atmosphere of reduced-pressure or reduced-pressure and containing mainly inert gas and nitrogen, wherein the ultraviolet light has an energy level higher than the binding energy of the Si—CH n bonds in said insulating film and lower than the binding energy of the Si—O—Si or other Si—O bonds in the skeleton, and wherein the irradiating is without oxidation, to break the Si—CH n bonds and free CH n groups, without affecting the skeleton; and (c) removing the free CH n groups from said insulating film.