A method of manufacturing a reticle, the method including preparing a substrate, determining position data of a pattern to be formed on the substrate, and setting a primary exposure condition to form the pattern; performing a primary exposure simulation regarding the substrate based on the position data of the pattern and the primary exposure condition; calculating a primary deformation rate of the substrate, which is generated in the primary exposure simulation; correcting the position data of the pattern based on the primary deformation rate of the substrate to provide a corrected position data of the pattern; and exposing the substrate under the primary exposure condition based on the corrected position data of the pattern.