EP0777147A1
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EP
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Method of forming a pattern and projecting exposure apparatus
Assignee: Hitachi Ltd
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Filing: 1991-09-27
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Granted: —
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Expires: 2011-09-27
Abstract
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(2πβr 2 - θ/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(2πβf 2 - θ/2) (where f is a spatial frequency, and β, θ 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 µm by the use of an optical exposure system.
Inventors
- 👤 Hiroshi Fukuda
- 👤 Tsuneo Terasawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 12:29
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/26; G03F1/30; H; H10; H10P; H10P14/00; H10P14/60; G03F1/29; G03F7/00; G03F7/20; G03F7/2002; G03F7/70; G03F7/70058; G03F7/70125; G03F7/70191; G03F7/70216; G03F7/70241; G03F7/70308; G03F7/70325; G03F7/70333; G03F1/36
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
72 words
A method of mask layout design comprising the steps of obtaining the Fourier transform of a layout pattern drawn on an LSI, multiplying the Fourier transform data by cos(2πβf 2 - θ/2) in the spatial frequency domain (where f is a dimensionless spatial frequency spectrum normalised by NA/λ, 0.3 < β < 0.7, and 10β < θ < 10β - 2 ), and taking the inverse Fourier transform of the resulting product.
Claim 2
Independent Claim
121 words
A method of mask production comprising the steps of obtaining the Fourier transform of a designed layout pattern drawn on an LSI, multiplying the Fourier transform data by cos(2πβf 2 - θ/2) in the spatial frequency domain (where f is a dimensionless spatial frequency vector normalised by NA/λ, 0.3 < β < 0.7 and 10β - 5 < θ < 10β - 2 ), taking the inverse Fourier transform of the resulting product to produce a pattern, and selectively forming a light absorbing layer and a phase-shifting layer of appropriate thickness on a transparent substrate in such a manner that the amplitude transmittance distribution of the mask selected one of said pattern and an approximate solution of said pattern thereof represents.
Claim 3
Dependent Claim
96 words
A mask produced by the steps of obtaining the Fourier transform of a layout pattern drawn on an LSI to, multiplying the Fourier transform data cos(2πβf 2 - θ/2) in the spatial frequent domain by (where f is a dimensionless spatial frequency vector normalised by NA/λ, 0.3 < β < 0.7, and 10β - 5 < θ < 10β - 2 ), and taking the inverse Fourier transform of the resulting product to produce a pattern, said mask having selected one of said pattern and an approximate solution of said pattern as an amplitude transmittance distribution.
Claim 4
Dependent Claim
20 words
A mask according to claim 3 exposed by projection under the illumination condition of 0.3 or less in coherence factor.
Claim 5
Dependent Claim
111 words
A mask comprising an opaque region including a main aperture pattern and sub-aperture patterns arranged substantially symmetrically around the peripheral part of the main aperture pattern and having a substantially opposite phase transmittance to the main aperture pattern, the center distance between the main aperture pattern and sub-aperture pattern being in the range defined by L = κλ/NA (where 0.6 < κ < 0.9), the relationship 2.5 < (S'.T')/(S o .T o ) < 5 being held between the area S o of the main aperture pattern the transmittance T o of the main aperture pattern, the area S' of the subaperture patterns and the transmittance T' of the subaperture patterns.
Claim 6
Dependent Claim
33 words
A mask according to claim 5, comprising a plurality of combinations of said aperture pattern and said subaperture patterns, wherein the phase transmittances of adjacent main patterns are relatively different from each other.
Claim 7
Dependent Claim
88 words
An optical filter disposed at selected one of the pupil plane of lens, a plane conjugate with the pupil plane and the stop position determining the aperture of the lens, wherein the complex amplitude transmittance distribution of said filter is represented by selected one of cos(2πβr 2 - θ/2) (where r is a radial coordinate of the pupil plane normalised by the maximum radius of the pupil, 0.3 < β < 0.7, and 10β -5 < θ < 10β - 2 ) and an appropriate discrete distribution thereof.
Claim 8
Dependent Claim
40 words
An optical lens comprising an optical filter according to claim 7 disposed at selected one of the substantial pupil plane of a lens, a plane conjugate with the pupil plane and the stop position determining the aperture of the lens.
Claim 9
Independent Claim
75 words
A method of manufacturing a semiconductor device comprising the steps of: preparing a mask having a predetermined pattern; preparing a projection lens structure having a filter with a first region and a second region for passing light in different phase each other: setting said semiconductor device at the exposure field of said lens structure; and exposing said mask with light to project said pattern on a principal surface of said device through said lens structure.
Claim 10
Dependent Claim
45 words
A method of manufacturing a semiconductor device according to claim 9, wherein said filter comprising a substrate through which said light passes without shifting said phase of light and a film on said substrate through which said light passes with shifting said phase of light.
Claim 11
Dependent Claim
32 words
A method of manufacturing a semiconductor device according to claim 10, wherein said substrate comprises quartz and said film comprises Al, Cr, MgF 2, SiO 2 or Al plus SiO 2 .
Claim 12
Dependent Claim
19 words
A method of manufacturing a semiconductor device according to claim 9, wherein said light comprising an excimer laser beam.
Claim 13
Dependent Claim
29 words
A method of manufacturing a semiconductor device according to claim 9, wherein one of said first and second regions comprises a Cr film pattern having a discrete thickness distribution.
Claim 14
Dependent Claim
41 words
A method of manufacturing a semiconductor device according to claim 9, wherein said filter forming the projected images of said pattern at first image plane and a second image plane, said principal surface being positioned between said first and second plane.
Claim 15
Dependent Claim
37 words
A method of manufacturing a semiconductor device according to claim 9, wherein said filter performing more uniform light intensity distribution along a light axis at the vicinity of the image plane compared with that without said filter.
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