| 摘要 |
PROBLEM TO BE SOLVED: To provide a Wynn-Dyson imaging system reducing thermal deformation.SOLUTION: A reticle prism and a wafer prism are made of a glass material having a thermal expansion coefficient of about 100 ppb/°C or less. A Wynn-Dyson imaging system comprises: a first window arranged between a reticle 16 and a reticle prism 110R; and a second window arranged between a wafer 18 and a wafer prism, and maintaining symmetry of an image. The first window substantially blocks arrival of convective heat and radiation heat at the reticle prism, thus reducing the amount of thermally-induced image deformation of a reticle image formed on the wafer. |
