Patent · US Expired

Projection lens and microlithographic projection exposure apparatus

US6879379B2 · kind B2 · utility

15Cited by
19References
51Claims
0Family size

Assignee

Inventors

Key dates

Filing dateNov 14, 2003
Grant dateApr 12, 2005
Priority date
Expiry dateNov 14, 2023

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG03F7/70966
  • WIPO fieldOptics
  • WIPO sectorInstruments

Abstract

A projection exposure apparatus for microlithography has a light source, an illumination system, a mask-positioning system and a projection lens. The latter has a system aperture plane and an image plane and contains at least one lens that is made of a material which has a birefringence dependent on the transmission angle. The exposure apparatus further has an optical element, which has a position-dependent polarization-rotating effect or a position-dependent birefringence. This element, which is provided close to a pupil plane of the projection exposure apparatus, compensates at least partially for the birefringent effects produced in the image plane by the at least one lens.

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