Methods of rasterizing mask layout and methods of fabricating photomask using the same

A method for fabricating a photomask, the method comprising:

• driving an image converter to obtain a raster image of a mask layout;
• driving a simulation tool to produce a contour image based on the raster image;
• driving a corrector to correct the mask layout based on a comparison of the contour image with a target image;
• and
• forming the photomask including mask patterns corresponding to the corrected mask layout, wherein obtaining the raster image includes:
• providing, on a grid, a pattern acquired from the mask layout;
• obtaining grid points surrounding an edge of the pattern;
• constructing, on the pattern, a path that extends from the edge toward adjacent edges of the pattern;
• and
• allocating a raster value to each of the grid points, the raster value corresponding to an overlap area between a pixel having a center located on one of the grid points and the pattern having a boundary limited by the path.

A method for correcting a mask layout, the method comprising:

• providing a pattern from the mask layout on a grid, the mask layout in a vector graphics format;
• obtaining grid points corresponding to an edge of the pattern;
• constructing a path on the pattern, the path extending from the edge toward a number of adjacent edges of the pattern, the path not extending around all of the pattern;
• generating a raster image of the mask layout by allocating raster values to the grid points, the raster values corresponding to an overlap area between a pixel and the pattern;
• producing a contour image based on the raster image;
• and
• correcting the mask layout based on a comparison of the contour image with a target image to fabricate a photomask corresponding to the corrected mask layout.