A new method to calculate intensity distribution in source mask optimization

We proposed a new method to perform intensity calculation for the Abbe´s image model. The method is similar to the decomposition of the transmission cross coefficients (TCC) of the optics system using sum of coherent systems decomposition (SOCS) by SVD. The singular values and kernels are derived efficiently for a pixel-based source. The intensity calculation can be expressed using sum of convolutions between mask and a few kernels and then largely reduce a large amount of convolution computations in the Abbe´s image model. This method can be used in the source and mask optimization (SMO) to increase computational efficiency.