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:
Nov. 09, 1999
Filed:
Oct. 10, 1997
Toshihiko Ishihara, San Diego, CA (US);
Thomas Hofmann, San Diego, CA (US);
Palash P Das, Vista, CA (US);
Alexander I Ershov, San Diego, CA (US);
Cymer, Inc., San Diego, CA (US);
Abstract
A very narrow band pulse excimer laser capable of producing pulses at a rate in the range of about 500 to 2000 Hz with enhanced energy dose control and reproducibility. A prior art burst mode 'slug effect' occuring at one gas circulation time after the beginning of a burst of pulses is eliminated by the addition of a minute quantity of oxygen. In a preferred embodiment very narrow bandwidth is achieved by reducing fluorine partial pressure to less than 0.10 percent and by increasing the reflectance of the output coupler to greater than 25 percent. In a preferred embodiment, prior art fused silica beam expansion prisms used in the prior art line narrowing module were replaced with calcium fluoride prisms.