Phase shifting mask topography effect correction based on near-field image properties

Abstract

Image intensity imbalance created by a phase shifting mask (PSM) layout can be corrected using a near-field image. Because an aerial image is not used, various parameters associated with the exposure conditions and stepper need not be considered, thereby significantly simplifying the computations to determine the appropriate correction. Of importance, using the near-field image can provide substantially the same correction generated using the aerial image. Thus, using the near-field image can provide an accurate and quick correction for image intensity imbalance between shifters of different phases. After correcting for the image intensity imbalance, additional proximity correction techniques can be applied to the layout to correct-for other effects.

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