Patent · US Active

Illumination system particularly for microlithography

US7977651B2 · kind B2 · utility

4Cited by
55References
20Claims
0Family size

Assignee

Inventors

Key dates

Filing dateAug 25, 2009
Grant dateJul 12, 2011
Priority date
Expiry dateDec 28, 2029

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG03F7/70358
  • WIPO fieldOptics
  • WIPO sectorInstruments

Abstract

There is provided a projection objective for a projection exposure apparatus that has a primary light source for emitting electromagnetic radiation having a chief ray with a wavelength≦193 nm. The projection objective includes an object plane, a first mirror, a second mirror, a third mirror, a fourth mirror; and an image plane. The object plane, the first mirror, the second mirror, the third mirror, the fourth mirror and the image plane are arranged in a centered arrangement around a common optical axis. The first mirror, the second mirror, the third mirror, and the fourth mirror are situated between the object plane and the image plane. The chief ray, when incident on an object situated in the object plane, in a direction from the primary light source, is inclined away from the common optical axis.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.