Patent ID: 7389491

Claim:
A method of correcting a photomask comprising: (a) selecting a monitoring pattern among mask patterns formed on a surface of a photomask and defining a boundary region to be opened for correcting the monitoring pattern; (b) defining a correction pattern for the selected monitoring pattern without an exposure on an electronic device substrate using an aerial image emulator capable of estimating a critical dimension (CD) transferred on the electronic device substrate through an aerial image of the electronic device substrate; and (c) opening the boundary region of the correction pattern to correct the correction pattern, wherein the operation (b) comprises: (b1) putting the photomask on a stage of the aerial image emulator; (b2) converting positions of the monitoring pattern and the boundary region into coordinates and storing the coordinates in the aerial image emulator; (b3) recognizing, at the aerial image emulator, an aerial image by a mask pattern of the photomask; (b4) finding a coordinate of the position and moving the stage to perform a first alignment between the photomask and the aerial image emulator; (b5) performing, at the aerial image emulator, a second alignment by comparing the recognized aerial image with an ideal simulated aerial image memorized in advance in the aerial image emulator; and (b6) recognizing, at the aerial image emulator, a difference between the ideal simulated aerial image and the recognized aerial image with respect to the monitoring pattern, and when the difference deviates from tolerance, defining the monitoring pattern as a correction pattern.