a method for preparing data for exposure includes forming a first plurality of rectangular patterns from a reticle preparing rule ; lining an object pattern for performing reticle exposure with the first rectangular patterns , and extracting a second plurality of rectangular patterns , disposed in an n × n matrix , from the first plurality of rectangular patterns in the object pattern ; and performing a violation detecting treatment and a correcting treatment of the pattern width and the pattern distance of the reticle exposure pattern on the basis of the distance between the second plurality of rectangular patterns .