The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 21, 2012
Filed:
Mar. 25, 2009
Julian Kaller, Koenigsbronn, DE;
Toralf Gruner, Aalen-Hofen, DE;
Julian Kaller, Koenigsbronn, DE;
Toralf Gruner, Aalen-Hofen, DE;
Carl Zeiss SMT GmbH, Oberkochen, DE;
Abstract
In a projection exposure method, primary radiation having a center wavelength λ is generated and guided through an illumination system along an illumination path and through a projection system along a projection path. The center wavelength is varied within a wavelength variation range Δλ having a lower limit λ≦λ and an upper limit λ≧λ. A specific absorption coefficient k(λ) of at least one gaseous absorbent species selected from the group consisting of oxygen (O), ozone (O) and water vapor (HO) present in at least one gas-filled space along at least one of the illumination path and the projection path varies between a minimum absorption coefficient kand a maximum absorption coefficient kwithin the wavelength variation range such that an absorption ratio (k/k) exceeds 10. A concentration of the absorbent species within the gas-filled space is controlled such that an overall absorption variation effected by the absorbent species for all rays running along differing ray paths towards the image field is maintained below a predetermined absorption variation threshold value.