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:
Jul. 08, 2003
Filed:
Jun. 21, 2001
Noriaki Kandaka, Kawasaki, JP;
Hideki Komatsuda, Ageo, JP;
Nikon Corporation, Tokyo, JP;
Abstract
Sources are disclosed for producing short-wavelength electromagnetic radiation (EMR) such as extreme ultraviolet (“EUV” or “soft X-ray”) radiation useful in microlithography. The sources collect a greater amount of the EMR produced by a plasma than conventional sources and form the collected EMR into an illumination EMR flux having higher intensity than conventionally. The EMR flux desirably has a rotationally symmetrical intensity distribution. The plasma is produced by two electrodes contained in a vacuum chamber. A high-voltage pulsed power supply applies a plasma-creating potential across the electrodes. EMR produced by the plasma is collected, typically by a reflective element configured to form a collimated beam of EMR. The electrodes are configured and oriented such that, as the collimated beam passes by the electrodes, the electrodes exhibit minimal blocking of the EMR flux. The electrodes can include a center electrode and a surrounding hollow cylindrical electrode separated from the center electrode by an insulating member. The axis of rotational symmetry of the electrodes desirably is substantially parallel to the propagation axis of the EMR flux.