Patent · US Expired

Microlithographic reduction projection catadioptric objective

US6636350B2 · kind B2 · utility

91Cited by

36References

26Claims

0Family size

Assignee

Carl Zeiss Stiftung · DE

Inventors

David Shafer · Fairfield, US
Russell Hudyma · San Ramon, US
Wilhelm Ulrich · Aalen, DE

Key dates

Filing date	Jan 16, 2001
Grant date	Oct 21, 2003
Priority date	—
Expiry date	Feb 27, 2021

Classification

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

Abstract

A photolithographic reduction projection catadioptric objective includes a first optical group having an even number of at least four mirrors and having a positive overall magnifying power, and a second substantially refractive optical group more image forward than the first optical group having a number of lenses. The second optical group has a negative overall magnifying power for providing image reduction. The first optical group provides compensative aberrative correction for the second optical group. The objective forms an image with a numerical aperture of at least substantially 0.65, and preferably greater than 0.70 or still more preferably greater than 0.75.

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