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US5863712A
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Pattern forming method, projection exposure system, and semiconductor device fabrication method
Assignee: Hitachi Ltd
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Filing: 1997-01-06
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Granted: 1999-01-26
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Expires: 2017-01-06
Abstract
Abstract The pattern forming method is capable of forming a projected image or photoresist pattern that is faithful to a designed pattern without performing complex correction of a mask pattern. A projection exposure system and a semiconductor device fabrication method employing this pattern forming method are also disclosed. Exposure is performed by setting a pupil filter with a variable amplitude transmittance to the pupil position of the projection lens of a projection exposure system. The pupil filter has a transparent substrate, a phase retarding layer, a translucent film, and an opaque stencil. The pupil filter is replaced or rotated during either a plurality of exposures or during a single exposure onto the same position on the surface of a wafer substrate that is to be exposed. It is possible to improve the fidelity of the contour of a pattern transferred image without improving the numerical aperture (NA) of a projection lens, decreasing the wavelength of exposure light, or locally correcting a mask pattern. It is also possible to prevent imperfect resolution from occurring and fabricate semiconductor integrated circuit devices with a high yield.
Inventors
- 👤 Rudolf Murai von Bunau
- 👤 Hiroshi Fukuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:38
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70058; G03F7/70125; G03F7/70216; G03F7/70258; G03F7/70308; G03F7/70425; G03F7/70466; G03F1/00; G03F1/36
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
127 words
A pattern forming method of projecting a pattern on a mask, having a top surface, onto a substrate through a projection lens in order to transfer the pattern onto the substrate, comprising the steps of: illuminating the pattern on the mask in a direction almost perpendicular to the top surface of the mask, with a pupil filter having a first pupil function disposed between the mask and the substrate, the pupil filter defining a pupil plane; changing the pupil filter with a first pupil function to a pupil filter with a second pupil function; and continuing illuminating the pattern on the mask, wherein at least one of the first and second pupil functions has an amplitude transmittance distribution that is asymmetric with respect to a pupil center.
Claim 2
Dependent Claim
127 words
A pattern forming method of projecting a pattern on a mask, having a top surface, onto a substrate through a projection lens in order to transfer the pattern onto the substrate, comprising the steps of: illuminating the pattern on the mask in a direction almost perpendicular to the top surface of the mask, with a pupil filter having a first pupil function disposed between the mask and the substrate, the pupil filter defining a pupil plane; changing the pupil filter with a first pupil function to a pupil filter with a second pupil function; and continuing illuminating the pattern on the mask, wherein at least one of the first and second pupil functions has an amplitude transmittance distribution that is asymmetric with respect to a pupil center.
Claim 3
Dependent Claim
69 words
The pattern forming method according to claim 1, wherein the pupil functions include pupil function A 1 and pupil function A 2 satisfying the following relations: A.sub.1 (X, Y)=A.sub.1 (-X, Y)=A.sub.1 (X, -Y)=A.sub.1 (-X, -Y), and A.sub.2 (X, Y)=-A.sub.2 (-X, Y)=-A.sub.2 (X, -Y)=A.sub.2 (-X, -Y), where X and Y denote orthogonal axes in the pupil plane and having an optical axis defined by the projection lens as an origin.
Claim 4
Dependent Claim
72 words
The pattern forming method according to claim 2, wherein the pupil function A 1 (X, Y) takes a value 1 in an entire pupil area, the pupil function A 2 (X, Y) takes any one of values 1, 0, and -1 in the pupil plane, and the area for which A 2 (X, Y)=0 has approximately the shape of a cross, covering an image of an effective source in the pupil plane.
Claim 5
Dependent Claim
62 words
The pattern forming method according to claim 1, wherein the pupil functions include pupil function B 1 and pupil function B 2 satisfying the following relations: B.sub.1 (X, Y)=B.sub.1 (Y, X)=B.sub.1 (-Y, -X), and B.sub.2 (X, Y)=B.sub.1 (-Y, X), where X and Y denote orthogonal axes in the pupil plane with an optical axis defined by the projection lens as an origin.
Claim 6
Dependent Claim
45 words
The pattern forming method according to claim 4, wherein the pupil function B 1 (X, Y) takes any one of values 1, 0.5, and 0 and an area for which B 1 (X, Y)=0.5 covers an image of an effective source in the pupil plane.
Claim 7
Dependent Claim
44 words
The pattern forming method according to claim 5, wherein the pupil function B 1 (X, Y) takes a value 1 or 0 in a pupil area and an area for which B 1 (X, Y)=0 is arranged symmetrically with respect to the pupil center.
Claim 8
Dependent Claim
99 words
The pattern forming method according to claim 1, further comprising the steps of: changing the pupil filter with the second pupil function to a pupil filter with a third pupil function; and continuing illuminating the pattern on the mask, wherein the pupil functions include pupil functions C 1 , C 2 , and C 3 meeting the following relations: C.sub.1 (X, Y)=C.sub.1 (-X, Y)=C.sub.1 (X, -Y)=C.sub.1 (-X, -Y), C.sub.2 (X, Y)=-C.sub.2 (-X, Y)=C.sub.2 (X, -Y), and C.sub.3 (X, Y)=C.sub.2 (-Y, X), where X and Y denote orthogonal axes in the pupil plane with the optical axis as the origin.
Claim 9
Dependent Claim
68 words
The pattern forming method according to claim 7, wherein the pupil function C 1 (X, Y) takes a value 1 in an entire pupil area, the pupil function C 2 (X, Y) takes any one of values 1, 0, and -1, and an area for which C 2 (X, Y)=0 has a shape of a stripe, which covers an image of an effective source in the pupil plane.
Claim 10
Dependent Claim
130 words
The pattern forming method according to claim 1 further comprising the steps of: changing the pupil filter with the second pupil function with a pupil filter with a third pupil function; continuing illuminating the pattern on the mask; changing the pupil filter with the third pupil function with a pupil filter with a fourth pupil function; and continuing illuminating the pattern on the mask, wherein the pupil functions include pupil functions D 1 , D 2 , D 3 , and D 4 meeting the following relations: D.sub.1 (X, Y)=D.sub.1 (Y, X), D.sub.2 (X, Y)=D.sub.1 (-Y, X), D.sub.3 (X, Y)=D.sub.1 (-X, -Y), and D.sub.4 (X, Y)=D.sub.1 (Y, -X), where X and Y denote orthogonal axes in the pupil plane with an optical axis of the projection lens as an origin.
Claim 11
Dependent Claim
45 words
The pattern forming method according to claim 9, wherein the pupil function D 1 (X, Y) takes any one of values 1, 0.5, and 0 and the area for which D 1 (X, Y)=0.5 covers an image of an effective source in the pupil plane.
Claim 12
Dependent Claim
28 words
The pattern forming method according to claim 1, wherein the pupil functions are realized using patterned opaque layers, partially absorbing layers and phase-retarding layers on a transparent substrate.
Claim 13
Dependent Claim
42 words
The pattern forming method according to claim 11, wherein the step of changing a pupil filter with a first pupil function to a pupil filter with a second pupil function involves physically replacing a first pupil filter with a second pupil filter.
Claim 14
Dependent Claim
39 words
The pattern forming method according to claim 1, wherein the step of changing a first pupil filter with a first pupil function to a second pupil filter with a second pupil function is accomplished by rotating the pupil filter.
Claim 15
Dependent Claim
42 words
The pattern forming method according to claim 1, wherein the step of changing a pupil filter with a first pupil function to a pupil filter with a second pupil function involves physically replacing a first pupil filter with a second pupil filter.
Claim 16
Dependent Claim
35 words
The pattern forming method according to claim 1, wherein the different pupil functions are realized using a patterned opaque layer, a partially phase-retarding layer on a transparent substrate and a stencil mask opaque to light.
Claim 17
Dependent Claim
39 words
The pattern forming method according to claim 15, wherein the step of changing a first pupil filter with a first pupil function to a second pupil filter with a second pupil function is accomplished by rotating the stencil mask.
Claim 18
Dependent Claim
63 words
The pattern forming method according to claim 1, wherein the pupil filter having the first pupil function and the pupil filter having the second pupil function are formed from by a patterned opaque, partially absorbing and phase-retarding layer on an optically birefringent substrate, and wherein a polarization of light used in the step of illuminating is changed during the step of continuing illuminating.
Claim 19
Independent Claim
63 words
A method for forming a pattern onto a substrate comprising the steps of: providing a mask having a predetermined pattern formed thereon; providing a pupil filter between the mask and the substrate, the pupil filter having a center and a pupil function with an asymmetric or anti-symmetric phase transmittance distribution with respect to its center; illuminating the mask in a substantially perpendicular direction.
Claim 20
Independent Claim
63 words
A method for forming a pattern onto a substrate comprising the steps of: providing a mask having a predetermined pattern formed thereon; providing a pupil filter between the mask and the substrate, the pupil filter having a center and a pupil function with an asymmetric or anti-symmetric phase transmittance distribution with respect to its center; illuminating the mask in a substantially perpendicular direction.
Claim 21
Dependent Claim
47 words
The method according to claim 18, wherein the pupil filter has a transparent substrate that is partially covered by a phase retarding layer, and wherein the method further comprises the step of laterally translating the transparent substrate in order to illuminate different portions of the transparent substrate.
Claim 22
Independent Claim
66 words
A method for forming a pattern onto a substrate comprising the steps of: providing a mask having a predetermined pattern formed thereon; providing a pupil filter between the mask and the substrate, the pupil filter having a center and a pupil function with an anti-symmetric amplitude transmittance distribution with respect to its center; illuminating the mask and changing filters as necessary to form the pattern desired.
Claim 23
Independent Claim
66 words
A method for forming a pattern onto a substrate comprising the steps of: providing a mask having a predetermined pattern formed thereon; providing a pupil filter between the mask and the substrate, the pupil filter having a center and a pupil function with an anti-symmetric amplitude transmittance distribution with respect to its center; illuminating the mask and changing filters as necessary to form the pattern desired.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2002-01-25 | 2002-07-27 | 2003-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-01-25 | 2006-07-27 | 2007-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-01-25 | 2010-07-27 | 2011-01-26 | $7700.00 | Window Closed / Lapsed |