Patent · US Expired

Projection optical system

US6992753B2 · kind B2 · utility

1Cited by

9References

38Claims

0Family size

Assignee

Carl Zeiss SMT GmbH · DE

Inventors

Daniel Krähmer · Aalen, DE
Eric Eva · Aalen, DE

Key dates

Filing date	Dec 24, 2003
Grant date	Jan 31, 2006
Priority date	—
Expiry date	May 16, 2024

Classification

Technology area (CPC G)Physics
CPC primaryG03F7/70958
WIPO fieldOptics
WIPO sectorInstruments

Abstract

Radiation-induced damage to a lens material in a projection exposure system is reduced by selection of maximum design fluence values HD for lenses and at least one lens made of a material having a characteristic transition point TRC after exposure to a given amount of radiation, wherein, for instance, TRC<0.8. HD among other relationships and/or characteristics of the lenses.

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