A method of correcting an overlay includes: forming a first pattern on a first substrate; forming a second pattern on the first pattern; obtaining a first overlay error profile of the second pattern and obtaining a first overlay correction profile from the first overlay error profile; forming a third pattern on the second pattern; obtaining a second overlay error profile of the third pattern and obtaining a second overlay correction profile from the second overlay error profile; and forming the second pattern on a second substrate, wherein the forming of the second pattern on the second substrate includes: determining whether the second overlay correction profile has a non-correctable model parameter; and when the second overlay correction profile has the non-correctable model, obtaining a preliminary correction profile to correct a position of the second pattern to be formed on the second substrate.