Patent ID: 7682760

Claim:
A method of manufacturing a Levenson-type mask including a transparent substrate and a light shielding film arranged on a main surface of said transparent substrate and having a plurality of opening portions, said opening portions including a same phase opening portion and a reverse phase opening portion, said reverse phase opening portion having a concave portion formed in said main surface, said concave portion having an undercut portion formed to extend to below an end portion of said reverse phase opening portion, said same phase opening portions and said reverse phase opening portions being set in pairs to form a first pattern in a processed object, comprising: an opening portion setting step of defining said same phase opening portion and said reverse phase opening portion on opposite sides of said first pattern; determining a distance between said pairs; setting said same phase opening portion in at least one of said opening portions that form said pairs opposed to each other if a distance between said pairs is less than or equal to a prescribed distance.