Patent ID: 7527695

Claim:
A method for cleaning a substrate comprises irradiating the substrate to be cleaned, with ultraviolet light or vacuum ultraviolet light (hereinafter referred to simply as the UV light), wherein the substrate to be cleaned is a substrate having a transmittance of at least 20% at the wavelength of the UV light; a second space containing a surface on the side of the substrate on which the cleaning is to be carried out (hereinafter referred to as the to-be-cleaned surface) and its vicinity, is an atmosphere comprising a gas (hereinafter referred to as the process gas) or a liquid (hereinafter referred to as the process liquid), which generates at least one of ozone, excited state oxygen atoms and active oxygen species by the irradiation with the UV light; a first space containing a surface on the other side of the substrate (hereinafter referred to as the to-be-irradiated surface) is an atmosphere comprising a gas showing a low absorption of the UV light; and the UV light is permitted to enter via the first space into the to-be-irradiated surface of the substrate, then pass through the interior of the substrate and then be applied to the to-be-cleaned surface.