Influence of birefringence on the image formation of high-resolution projection optics

The influence of birefringence on high-resolution projection optics used fo r microlithography is investigated theoretically. A formula for partially c oherent imaging that is based on the scalar diffraction theory is extended to include the birefringent properties of lens materials, By the determinat ion of the birefringent properties of lens materials by use of random numbe rs, data on 200 lenses, each composed of 10 birefringent elements, are gene rated to estimate statistically the degree of imaging-performance degradati on. As a result, it was found that the image contrast of a five-bar pattern decreases as a quadratic function of the maximum magnitude of the birefrin gence that was set in common for all. elements in each lens data set. (C) 2 000 Optical Society of America OCIS codes: 110.3000, 110.5220, 260.1440.