Method for manufacturing a photomask

A manufacturing method for a photomask based on design data indicating plurality of first figure elements comprising the steps of;

• extracting first data from the design data indicating a first figure element;
• forming a first figure element group including the first figure element and first figure elements affecting the first figure element due to the optical proximity effect;
• assigning identical identification data to a identical first data group indicating the first figure element group;
• estimating a influence of an optical proximity effect on the first figure element group;
• generating second data indicating a second figure element for compensating the influence of the optical proximity effect on the first figure element group;
• configuring figure data indicating plurality of second figure elements by assigning identical second data to the identical first data being included in the identical first data group with the identical identification data;
• and
• forming photomask patterns on the photomask using the figure data.