Alignment device

Abstract

Abstract PURPOSE:To contrive the improvement of alignment accuracy by a method wherein such a detecting optical system as a two focal point optical system is provided in the illuminating light sending optical path of an alignment optical system and illuminating light itself is focused on two points so as to correspond to the amount of chromatic aberration. CONSTITUTION:Exposure light and illuminating light for alignment are separated by a dichroic mirror 22 and an alignment optical system is so contrived as to be able to observe simultaneously a reticle 1 and a wafer 4 by the illuminating light which is hard to sensitize a resist even during exposure. Moreover, a two focal point optical system 21 is provided in an illuminating light sending optical path of the alignment optical system and the illuminating light for alignment is condensed on two focal points using this optical system 21 in such a way as to correspond to the amount of chromatic aberration of a projection lens 3. Thereby, the need to provide a correcting optical system in an alignment optical path between the reticle 1 and the water 4 is eliminated and a mark on the reticle and a mark on the wafer are directly detected to make possible a high-accuracy alignment.

Inventors

• 👤 Nobutaka Umagome
• 👤 伸貴 馬込

Bibliographic Details