Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making electrical device
Patent
1995-10-18
1997-01-21
Rosasco, S.
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making electrical device
430312, 430322, 430325, 2504911, 2504921, G03C 500
Patent
active
055958575
ABSTRACT:
A novel method of pattern formation and a projection exposure apparatus are disclosed, in which the pupil of a projection lens of the projection exposure apparatus used for forming an LSI pattern or the like has mounted thereon an optical filter having a complex amplitude transmittance distribution expressed substantially as T(r)=cos (2.pi..beta.r.sup.2 -.theta./2) as a function of a radial coordinate r normalized by the maximum radius of the pupil. Alternatively, Fourier transform of a layout pattern drawn on the LSI is obtained, an obtained Fourier transform data is multiplied by cos (2.pi..beta.f.sup.2 -.theta./2) (where f is a spatial frequency, and .beta., .theta. appropriate real numbers), the inverse Fourier transform of the resulting product is taken to produce a pattern, and this pattern or an approximate solution thereof is used as a mask pattern thereby to produce an LSI by exposure. As a result, even when the NA is increased and the wavelength shortened to improve the resolution limit, a large depth of focus and a high image quality are obtained at the same time. It is thus possible to form a pattern of 0.2 to 0.3 .mu.m by the use of an optical exposure system.
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Progress In Optics, vol. 2, 1963, pp. 133-152.
Fukuda Hiroshi
Terasawa Tsuneo
Hitachi , Ltd.
Rosasco S.
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