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:
Mar. 04, 2014
Filed:
Jul. 20, 2012
Erik Petrus Buurman, Veldhoven, NL;
Szilard Istvan Csiszar, Veldhoven, NL;
Erik Petrus Buurman, Veldhoven, NL;
Szilard Istvan Csiszar, Veldhoven, NL;
ASML Netherlands B.V., Veldhoven, NL;
Abstract
A lithographic apparatus includes an illuminator for receiving a beam of EUV radiation from a radiation source apparatus and for conditioning the beam to illuminate a target area of a patterning device, such as a reticle. The reticle forms a patterned radiation beam. A projection system transfers the pattern from said patterning device to a substrate by EUV lithography. Sensors are provided for detecting a residual asymmetry in the conditioned beam as the beam approaches the reticle, particularly in a non-scanning direction. A feedback control signal is generated to adjust a parameter of said radiation source in response to detected asymmetry. The feedback is based on a ratio of intensities measured by two sensors at opposite ends of an illumination slit, and adjusts the timing of laser pulses generating an EUV-emitting plasma.