Photocopying – Projection printing and copying cameras – Step and repeat
Patent
1993-04-02
1994-10-25
Gellner, Michael L.
Photocopying
Projection printing and copying cameras
Step and repeat
355 67, 355 71, G03B 2742
Patent
active
053593880
ABSTRACT:
In the microlithographic projection system disclosed herein, a reticle whose image is to be projected is illuminated with light having an essentially uniform intensity distribution over the reticle and angular distribution which is annularly concentrated. The annular concentration is produced by a phase grating interposed between the light source and a kaleidoscope which generates multiple overlapping images of this light source. The grating employs an array of elements of differing transmission phasings which suppresses zero order transmission and concentrates incident energy in an annularly diverging beam array.
REFERENCES:
patent: 4992825 (1991-02-01), Fukuda et al.
patent: 5113286 (1992-05-01), Morrison
patent: 5264898 (1993-11-01), Kamon et al.
patent: 5291012 (1994-03-01), Shimizu et al.
"Phase-Shifting Mask and FLEX method for Advanced Photo-lithography"--H. Fukuda et al.--SPIE vol. 1264 Optical/Laser Microlithography III (1990)--pp. 14-25.
"A Novel Method for Improving the Defocus Tolerance in Step and Repeat Photolithography"--T. Hayashida et al.--SPIE vol. 772 Optical Microlithography VI (1987)--5 pages.
Gellner Michael L.
General Signal Corporation
Malley Daniel P.
Pahl Jr. Henry D.
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