| 摘要 |
PURPOSE:To detect and correct possible unsymmetry of a lattice by positioning the pattern of a reticle on a wafer with high precision, through the medium of interference fringes, and further estimating the shape of the lattice formed on the wafer. CONSTITUTION:Light emitted from a light source 11 is enlarged with a beam expander 12, converted to parallel rays or converged rays by passing an illuminating-optical system 13 composed of collimator lenses or condenser lenses, and enters the entrance pupil of the first lense system 15. A reticle 14 is set between the light source optical system 13 and the first fourier transformation lense 15. The image coming out of the pattern of the reticle 14 serving as the second light source is once converged with the first fourier transformation lense 15, and further projected to a wafer 18 through the second fourier transformation lense 17. The pattern formed on the reticle 14 forms interference fringes on the wafer surface 17 by filtering on the spectrum plane. |
