PURPOSE: To improve the performance of a projection lens by combining ≥2 kinds of glass materials whose refractive indexes due to abnormal dispersion of specific wavelength are controlled.
CONSTITUTION: Light of an (i) ray (365 or 313nm) is projected from an alignment illumination system 34, e.g. Xe-Hg extra-high voltage lamp by using a cut filter to illuminate the main beam splitter 26 of a main optical system by a beam splitter 31 for alignment. At this time, optional lighting is performed by an alignment system XY driving system 35 according to alignment mark position on a reticle and a wafer, and the alignment mark 25A on the reticle 5 and the alignment mark 313 on the wafer 29 are irradiated with light in a 313 or 365nm ultraviolet ray range at the same time. Its reflected light is returned to the alignment mark on the wafer 29 and a lens 30 for alignment. Consequently, a high-accuracy projection lens of a single quartz system usable in the far ultraviolet ray range is manufactured.
SASAKO MASARU
ENDO MASATAKA
ISHIHARA TAKESHI
| JPS61129828A | 1986-06-17 |