In the invention of this application, the resist pattern having a given pattern of opening concavity is formed on the component to be dry etched, the aqueous solution containing a water-soluble resin is filled in that opening concavity, and the filled aqueous solution containing a water-soluble resin is dried into a narrow shrunk resin at the middle of the opening concavity, whereby the mask of shrunk resin is formed. It is thus possible to form a micropattern much finer than determined by optical limits.