Method for repairing damage of dielectric film by hydrocarbon restoration and hydrocarbon depletion using UV irradiation

A method for repairing process-related damage of a dielectric film formed on a substrate caused by processing the dielectric film, wherein the damaged dielectric film has a first carbon content and a first dielectric constant, comprising:

• forming a hydrocarbon film on a surface of the damaged dielectric film by irradiating the damaged dielectric film with UV light in an atmosphere of hydrocarbon-containing gas to react the surface of the damaged dielectric film with activated carbon, thereby restoring the surface with the hydrocarbon film, said hydrocarbon film having a thickness of about 1 nm to about 10 nm and being a layer continuously extending in a direction perpendicular to a thickness direction substantially without pinholes to cover the surface of the damaged dielectric film, wherein the surface-restored dielectric film has a second carbon content which is higher than the first carbon content, and a second dielectric constant which is lower than the first dielectric constant;
• and
• partially removing the hydrocarbon film by irradiating the surface-restored dielectric film with UV light in an atmosphere of oxygen gas, resulting in a hydrocarbon-depleted film, thereby further repairing the damaged dielectric film, wherein the hydrocarbon-depleted dielectric film has a third carbon content which is lower than the second carbon content, and a third dielectric constant which is lower than the second dielectric constant.