Patent ID: 8052797

Claim:
A method for removing inorganic foreign matters from a surface of a substrate made of silicon or glass or a surface of an inorganic coating formed on the substrate, comprising: providing the substrate in an oxygen- or ozone-containing atmosphere having an oxygen concentration or an ozone concentration sufficient to generate uncrosslinked oxygen radicals on the surface of the substrate or the surface of the inorganic coating with irradiation of a light beam; applying to the surface of the substrate or to the surface of the inorganic coating a light beam in a wavelength range which makes a light absorption coefficient of at least one of a material of the substrate, a material of the inorganic coating and the inorganic foreign matters be at least 0.01/cm in an application amount of at least 10 J/cm 2 in the oxygen -or ozone-containing atmosphere, wherein the application of the light beam generates uncrosslinked oxygen radicals on the surface of the substrate or the surface of the inorganic coating; and exposing the surface of the substrate or the surface of the inorganic coating to an acidic solution having a pH ≦6 after the applying of the light beam such that the surface of the substrate or the surface of the inorganic coating has a negative surface potential.