Patent ID: 8365106

Claim:
A method comprising: generating, by a computer, effective source data and mask data to be used in an exposure apparatus including an illumination optical system which illuminates a mask by using light from a light source, and a projection optical system which projects a pattern of the mask onto a substrate; and fabricating a mask based on the generated mask data, wherein the mask data generation step includes setting a target pattern to be formed on the substrate, an effective source, and an exposure parameter settable in the exposure apparatus, calculating a first aerial image to be formed on an image plane of the projection optical system, based on the set target pattern, effective source, and exposure parameter, deciding a pattern of the mask based on the calculated first aerial image, calculating a diffracted light distribution to be formed on a pupil plane of the projection optical system, based on the decided pattern, deciding a new effective source based on the calculated diffracted light distribution and the set exposure parameter, and changing the set effective source to the new effective source, calculating a second aerial image to be formed on the image plane, based on the decided mask pattern, the decided new effective source, and the set exposure parameter, evaluating the calculated second aerial image, and determining whether the calculated second aerial image satisfies an evaluation criterion, and generating data containing data of the decided new effective source as the effective source data, if it is determined that the calculated second aerial image satisfies the evaluation criterion, and generating data containing data of the decided pattern as the mask data, wherein the calculating step of the first aerial image includes changing at least one of a relative position between elements of the target pattern and a shape of an element of the target pattern, and calculating the first aerial image of the changed target pattern, and in the deciding pattern, the pattern of the mask is decided based on the calculated aerial images.