Method for correcting a mask layout and method of fabricating a semiconductor device using the same

A method of manufacturing a semiconductor device, the method comprising:

• designing a mask layout including first patterns, each of the first patterns having a size related to a first critical dimension (CD) value;
• correcting the mask layout;
• fabricating a photomask having mask patterns corresponding to the corrected mask layout;
• and
• performing a photolithography process using the photomask on a wafer,
• wherein the correcting of the mask layout comprises:
• generating a defocus map using topography data on a region of the wafer;
• and
• correcting the mask layout on a basis of the defocus map,
• wherein the generating of the defocus map comprises respectively setting second CD values for a plurality of sub-regions of the mask layout,
• wherein the second CD values are set based on the topography data.