Abstract: In a method of forming very minute real window patterns to a negative photoresist film that are required in the manufacture of highly packed semiconductor devices, false unexposed patterns are formed in the proximity of the minute real unexposed patterns. The false patterns have a width that, upon a single exposure of the negative photoresist film to ultraviolet light or other energy beam, the photoresist film portion immediately below the false patterns are unexposed but a photoresist portion under the unexposed portion is exposed to light by reason of light diffraction or light circling around under the false pattern. As a result, the false patterns in the photoresist film substantially disappear after development of the photoresist. The partially removed false patterns serve to negate swelling of the photoresist at the time of development and prevent obliteration of the real window patterns or formation of burr-like parts where the real window patterns are to be formed.