Correlation of the vector diffraction effect on the optical lithographic image of a binary mask with magnification of the projection system

Abstract

We show quantitatively through a computer simulation the effect of vector diffraction on the image in optical lithography. The simulation was made with a new program, and the variation of diffraction as the magnification was varied was calculated for various numerical apertures and degrees of defocus. The diffraction at the mask improves the images of lines across the polarizing direction, and the diffraction at the lens improves the images of the lines along the polarizing direction. We investigated the difference between images of lines along and across the polarizing direction as the magnification increased. Our result shows that the effect of the lens is so dominant that the images of lines along the polarizing direction are always better. (C) 1998 Optical Society of America.