PRODUCTION OF STAMPER

PROBLEM TO BE SOLVED: To lower a ratio occupied by a servo area and to increase a recording area for data by executing the development of a photosensitive resist film in such a manner that the developing speed in a thickness direction is higher than the developing speed in a surface direction. SOLUTION: If the developing speed in the thickness direction is higher than the developing speed in the surface direction, the development may be progressed down to the prescribed depth while a developed area does not spread on the upper side of the resist. Consequently, recessed parts are so formed as to substantially eliminate the difference in the sectional areas on the upper side and the lower side on a resist master disk, by which steep edges are formed. Then, the rugged shapes of steep edges are also formed on a stamper formed with rugged patterns as the inversion patterns. The developing speed in the thickness direction may be higher than the developing speed in the surface direction simply by previously treating the resist film before the exposure by an alkaline soln.