Abstract

Extreme ultraviolet lithography (EUVL) is a new technique for the mass production of future integrated circuits with a minimum feature size below 100 nm. One of the biggest technological barriers is the need for uniform illumination over a large area. We have designed and developed an illumination optics for EUVL that consists of four mirrors and provides an illuminated area 100 mm × 125 mm in size. It is applicable to EUVL optics based on a ring-shaped scanning field such as that provided by two-aspherical mirror reduction optics.¹ This large area was achieved by means of the synchronous movement of the third mirror and the mask stage.

© 1995 IEEE