Fast reconstruction of the aberrated scanning lithographic image by a quadratic imaging model and an integral transfer function.

Abstract

Since the pupil function is defined as a time-invariant system, the traditional partially coherent imaging model is time-consuming to calculate the effect of spatially varying wavefront aberrations on the scanning image. A fast reconstruction method of the aberrated scanning aerial image is presented for the scanning projection lithographic tool. In the proposed method, the principal components (PCs) are used to decompose and reconstruct the aberrated aerial image. Due to the exact quadratic relationship between the PC coefficients and the Zernike coefficients, the integration of the PCs in the intensity domain can be transformed into the integration of quadratic Zernike vectors when reconstructing the scanning aerial image. An integral transfer function is introduced to describe this process. This method can not only reconstruct the aberrated scanning image quickly but can also obtain the explicit relationship between the Zernike coefficients and the aberrated scanning aerial image.