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:
Sep. 21, 1999
Filed:
Sep. 18, 1997
David M Williamson, West Malvern, GB;
SVG Lithography Systems, Inc., Wilton, CT (US);
Abstract
An all reflective ring field projection optic system for use in scanning photolithography used in the manufacture of semiconductor wafers. The projection optics are designed for wavelengths in the extreme ultraviolet ranging from 11 to 13 nm to provide an arcuate image field for a reduction step and scan photolithography system. A sequence or configuration of mirrors from the long conjugate end to the short conjugate end consists of a convex, concave, convex, and concave mirror with an aperture stop being formed at or near the second convex mirror. This sequence of mirror powers provides a relatively large image field size while maintaining a relatively compact reticle wafer distance of less than 900 mm. The projection optics form an instantaneous annual field of up to 50 mm.times.2 mm at the wafer, permitting scanning to cover a field on a wafer of at least 50 mm.times.50 mm, greatly increasing throughput. The optical projection system can print features as small as 0.05 microns.