Patent ID: 8021804

Claim:
A photomask manufacturing method of placing, on a placing portion of a rotating apparatus, a mask blank formed by stacking a mask pattern thin film and a resist film on a substrate in this order, placing the mask blank in an exposure/writing apparatus while controlling an orientation of the mask blank using the rotating apparatus, and exposing/writing a mask pattern in the resist film using the exposure/writing apparatus, the method comprising: a defect information storage step of storing defect information into an information storage device in correspondence to an identification marker, the defect information including a type of a defect about at least one of the substrate, the mask pattern thin film, and the resist film in the mask blank provided with the identification marker on at least one end face of the substrate, and a position of the defect specified using a position of the identification marker as a reference; a placing orientation determination step of determining a placing orientation of the mask blank with respect to the exposure/writing apparatus using an orientation of the identification marker as a reference; and an orientation correction step of performing rotation control of the rotating apparatus using the orientation of said identification marker as a reference so that an orientation of the mask blank on the placing portion coincides with the placing orientation determined in the placing orientation determination step, wherein the placing orientation determination step detects the identification marker of the mask blank placed on the placing portion using a sensor, refers to the information storage device to obtain the defect information, and determines, based on writing information of the mask pattern to be exposed/written by the exposure/writing apparatus and the defect information, the placing orientation that achieves an arrangement of the mask pattern on the substrate in which the defect does not adversely affect a pattern transfer function of a photomask produced from the mask blank.