Method of etch proximity correction and method of creating photomask layout using the same

A method of creating a photomask, comprising:

• designing a target layout comprising a pattern region;
• performing etch proximity correction to create a measurement layout;
• and
• performing optical proximity correction to create the photomask,
• wherein the performing of the etch proximity correction comprises:
• setting a target position on an edge of a target pattern in a pattern region of a target layout;
• setting a proximity region affecting the target position by the etch reaction when the target pattern is etch-patterned;
• obtaining a project area radially extending from the target position toward an outermost portion of the proximity region and ending within the proximity region;
• obtaining a non-project area corresponding to an area extending past an end of the project area to the outermost portion of the proximity region;
• calculating an etch bias value using the project area, and the non-project area;
• and
• correcting the target position in the target pattern using the etch bias value and creating patterned wafer using the corrected target pattern.