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:
Apr. 02, 2013
Filed:
Aug. 25, 2011
Ralf Mueller, Aalen, DE;
Aksel Goehnermeier, Aalen, DE;
Wolfgang Singer, Aalen, DE;
Carl Zeiss SMT GmbH, Oberkochen, DE;
Abstract
A projection objective has an object surface and an image surface. The projection objective includes a plurality of optical elements arranged along an optical axis and configured so that during operation the projection objective images a pattern arranged in the object surface onto the image surface. The optical elements include a concave mirror a first deflecting mirror and a second deflecting mirror. The first deflecting mirror is tilted relative to the optical axis by a first tilt angle, t, about a first tilt axis so that during operation the first deflecting mirror deflects light at a wavelength λ from the object surface towards the concave mirror or deflects light at λ from the concave mirror towards the image surface. The second deflecting mirror is tilted relative to the optical axis by a second tilt angle, t, about a second tilt axis. For a pattern including a grating having a line width of 45 nm and a pitch, p, the projection objective images the pattern to the image surface such that for a first orientation of the pattern and a second orientation of the pattern a difference, ΔHV, between the imaged line width is 1.2 nm or less for 100 nm<p<1,000 nm, where the grating lines in the first orientation are orthogonal to the grating lines in the second orientation.