Patent · US Active

EUV lithography apparatus and method for determining the contamination status of an EUV-reflective optical surface

US8054446B2 · kind B2 · utility

2Cited by

7References

15Claims

0Family size

Assignee

Carl Zeiss SMT GmbH · DE

Inventors

Dieter Kraus · Munich, DE
Dirk Heinrich Ehm · Beckingen, DE
Stefan Schmidt · Aalen, DE

Key dates

Filing date	Aug 21, 2008
Grant date	Nov 8, 2011
Priority date	—
Expiry date	Jan 19, 2030

Classification

Technology area (CPC G)Physics
CPC primaryG01N2021/945
WIPO fieldMeasurement
WIPO sectorInstruments

Abstract

The invention relates to an EUV lithography apparatus with at least one EUV-reflective optical surface and a cavity ringdown reflectometer adapted to determine the contamination status of the EUV-reflective optical surface for at least one contaminating substance by determining the reflectivity of the EUV-reflective optical surface for radiation at a measuring wavelength (λm). The invention further relates to a method for determining the contamination status of at least one EUV-reflective optical surface arranged in an EUV lithography apparatus for at least one contaminating substance comprising determining the reflectivity of the EUV-reflective optical surface for radiation at a measuring wavelength (λm) using a cavity ringdown reflectometer.

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