1
David R Shafer, Yung Ho Chuang, Bin Ming B Tsai: Broad spectrum ultraviolet catadioptric imaging system. KLA Instruments Corporation, Thomas Schneck, Mark Protsik, February 10, 1998: US05717518 (103 worldwide citation)

An ultraviolet (UV) catadioptric imaging system, with broad spectrum correction of primary and residual, longitudinal and lateral, chromatic aberrations for wavelengths extending into the deep UV (as short as about 0.16 .mu.m), comprises a focusing lens group with multiple lens elements that provide ...


2
David R Shafer, Russell Hudyma, Wilhelm Ulrich: Microlithographic reduction projection catadioptric objective. Carl Zeiss Stiftung, Darby & Darby, October 21, 2003: US06636350 (82 worldwide citation)

A photolithographic reduction projection catadioptric objective includes a first optical group having an even number of at least four mirrors and having a positive overall magnifying power, and a second substantially refractive optical group more image forward than the first optical group having a n ...


3
David R Shafer, Abe Offner, Rama Singh: Optical relay system with magnification. The Perkin Elmer Corporation, Thomas P Murphy, Edwin T Grimes, Francis L Masselle, May 31, 1988: US04747678 (76 worldwide citation)

There is disclosed a ring field relay optical system incorporating concave spherical mirrors and including magnification achieved, at least partially, by a convex spherical mirror. In further modifications, aberrations introduced by the convex mirror are controlled by lens groups formed from fused s ...


4
David R Shafer, Alois Herkommer, Karl Heinz Schuster, Gerd Fürter, Rudolf von Bünau, Wilhelm Ulrich: Catadioptric objective comprising two intermediate images. Carl Zeiss Stiftung, July 29, 2003: US06600608 (75 worldwide citation)

An objective comprising axial symmetry, at least one curved mirror and at least one lens and two intermediate images. The objective includes two refractive partial objectives and one catadioptric partial objective. The objective includes a first partial objective, a first intermediate a image, a sec ...


5
Simon J Cohen, Hwan J Jeong, David R Shafer: Four-mirror extreme ultraviolet (EUV) lithography projection system. Ultratech Stepper, The Regents of the University of California, Allston L Jones, November 7, 2000: US06142641 (69 worldwide citation)

The invention is directed to a four-mirror catoptric projection system for extreme ultraviolet (EUV) lithography to transfer a pattern from a reflective reticle to a wafer substrate. In order along the light path followed by light from the reticle to the wafer substrate, the system includes a domina ...


6
John H Bruning, Anthony R Phillips Jr, David R Shafer, Alan D White: Lens system for X-ray projection lithography camera. Tropel Corporation, Eugene Stephens & Associates, October 4, 1994: US05353322 (66 worldwide citation)

Optimum solutions for three-mirror lenses for projection lithography cameras using X-ray radiation to image a mask on a wafer are represented as single points within regions of two-dimensional magnification space defined by the magnification of a convex mirror as one coordinate and the ratio of the ...


7
David R Shafer: Four mirror unobscurred anastigmatic telescope with all spherical surfaces. The Perkin Elmer Corporation, Salvatore A Giarratana, Francis L Masselle, Edwin T Grimes, October 7, 1980: US04226501 (58 worldwide citation)

A telescope made only of spherical mirrors including a first mirror system comprising a first, concave spherical mirror and a second, convex spherical mirror have a common center of curvature, the ratio of the radius of said first, concave mirror to said second convex mirror being approximately .sqr ...


8
David R Shafer: Microlithographic reduction projection catadioptric objective. Carl Zeiss Stiftung, Darby & Darby, March 29, 2005: US06873476 (54 worldwide citation)

The invention concerns a microlithographic reduction projection catadioptric objective having an even number greater than two of curved mirrors, being devoid of planar folding mirrors and featuring an unobscured aperture. The objective has a plurality of optical elements, and no more than two optica ...


9
David R Shafer: Reflective projection system comprising four spherical mirrors. Ultratech Stepper, Allston L Jones, April 25, 1995: US05410434 (54 worldwide citation)

The reflective projection system has a relatively wide field of view that comprises two concave and two convex spherical mirrors, situated in certain non-light-blocking positions with respect to one another, for deriving, with negligible image aberrations, a projected magnified or demagnified image ...


10
David R Shafer: Restrictive off-axis field optical system. The Perkin Elmer Corporation, Edwin T Grimes, Thomas P Murphy, September 4, 1984: US04469414 (53 worldwide citation)

This invention is directed to a restricted off-axis field optical system having a broad spectral range, which first and second nearly concentric optical subsystems, said subsystems being constructed and arranged with respect to each other so that variation in performance of one subsystem with wavele ...