An insulation film comprising an organosilicon polymer and an organic polymer such as polyarylene, polyarylene ether, polyimide, and fluororesin is disclosed, wherein the organosilicon polymer has a relative dielectric constant of 4 or less and has a dry etching selection ratio of 1/3 or less to silicon oxide, fluorine-doped silicon oxide, organosilicate glass, carbon-doped silicon oxide, methyl silsesquioxane, hydrogen silsesquioxane, a spin-on-glass, or polyorganosiloxane. The insulation film is used as an etching stopper or a hard mask in a dry etching process of interlayer dielectric films for semiconductors and can produce semiconductors having excellent precision with minimal damages.
