US5161059A
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US
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High-efficiency, multilevel, diffractive optical elements
Assignee: Massachusetts Institute of Technology
•
Filing: 1989-08-29
•
Granted: 1992-11-03
•
Expires: 2009-08-29
Abstract
Abstract A high-efficiency, diffractive optical element having at least one surface including multilevel steps, the steps determined by calculating equiphase boundaries utilizing a disclosed equation and algorithm. The optical element can be adapted to correct for chromatic and/or spherical aberration, and can be used in UV lithographic apparatus.
Inventors
- 👤 Gary J. Swanson
- 👤 Wilfrid B. Veldkamp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:21
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70216; G03F7/70308; G02; G02B; G02B27/00; G02B27/42; G02B27/4205; G02B27/4211; G02B27/4216; G02B27/4222; G02B3/00; G02B3/02; G02B3/08; G02B5/00; G02B5/18; G02B5/1847; G02B5/1857; G02B5/1876; G03F1/00; G03F7/0005; G03F7/001
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
83 words
High-efficiency, diffractive optical element having at least one surface including multilevel steps, the steps determined by calculating equiphase boundaries utilizing the equation ##EQU6## where x and y denote coordinates on the optical element, λ denotes wavelength, and a nm represents a series of optimized coefficients, and the algorithm ______________________________________
Equiphase Boundaries
Level #N (l = 0, ±1, ±2, . . .)
Phase Etch Depth θ
______________________________________
1 φ(x, y) = (l + 1)π
π
##STR14##
##STR15##
3
##STR16##
##STR17##
4
##STR18##
##STR19##
______________________________________
Claim 2
Dependent Claim
83 words
High-efficiency, diffractive optical element having at least one surface including multilevel steps, the steps determined by calculating equiphase boundaries utilizing the equation ##EQU6## where x and y denote coordinates on the optical element, λ denotes wavelength, and a nm represents a series of optimized coefficients, and the algorithm ______________________________________
Equiphase Boundaries
Level #N (l = 0, ±1, ±2, . . .)
Phase Etch Depth θ
______________________________________
1 φ(x, y) = (l + 1)π
π
##STR14##
##STR15##
3
##STR16##
##STR17##
4
##STR18##
##STR19##
______________________________________
Claim 3
Dependent Claim
19 words
The high-efficiency, diffractive optical element of claim 1, wherein the multilevel steps are adapted to correct for chromatic aberration.
Claim 4
Dependent Claim
19 words
The high-efficiency, diffractive optical element of claim 1 wherein the multilevel steps are adapted to correct for spherical aberration.
Claim 5
Dependent Claim
28 words
In UV lithographic apparatus, an optical system including at least one optical element, one surface of said optical element including a multilevel step pattern adapted for aberration correction.
Claim 6
Dependent Claim
28 words
In UV lithographic apparatus, an optical system including at least one optical element, one surface of said optical element including a multilevel step pattern adapted for aberration correction.
Claim 7
Dependent Claim
43 words
UV lithographic exposure system comprising: a source of UV radiation; and an optics column for generating an optical beam or image, the optics column including at least one optical element, one surface of which includes a multilevel step pattern adapted for aberration correction.
Claim 8
Dependent Claim
43 words
UV lithographic exposure system comprising: a source of UV radiation; and an optics column for generating an optical beam or image, the optics column including at least one optical element, one surface of which includes a multilevel step pattern adapted for aberration correction.
Claim 9
Dependent Claim
21 words
The lithographic exposure system of claim 5 wherein the at least one optical element corrects both for spherical and chromatic aberration.
Claim 10
Dependent Claim
85 words
The lithographic exposure system of claim 5 wherein the steps of the multilevel step pattern are determined by calculating equiphase boundaries utilizing the equation ##EQU7## where x and y denote coordinates on each optical element, λ denotes wavelengths, and a nm represents a series of optimized coefficients, and the algorithm ______________________________________
Equiphase Boundaries
Level #N (l = 0, ±1, ±2, . . .)
Phase Etch Depth θ
______________________________________
1 φ(x, y) = (l + 1)π
π
##STR20##
##STR21##
3
##STR22##
##STR23##
4
##STR24##
##STR25##
______________________________________
Claim 11
Dependent Claim
26 words
The lithographic exposure system of claim 5 wherein the source of UV radiation has a wavelength in the range of substantially 190 nm to 300 nm.
Claim 12
Dependent Claim
17 words
The lithographic exposure system of claim 5 wherein the source of UV radiation is an eximer laser.
Claim 13
Dependent Claim
16 words
The lithographic exposure system of claim 5 wherein the UV radiation source is a mercury lamp.
References Cited (Backward Citations)
US3586412A
Cited
US3726732A
Cited
US4327171A
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US4252891A
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US4434224A
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GB2129157A
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US4414059A
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US4737447A
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US4564584A
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US4579812A
Cited
US4690880A
Cited
US4724043A
Cited
US4632898A
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US4936665A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-11-03 | 1996-05-04 | 1996-11-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-03 | 2000-05-04 | 2000-11-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-03 | 2004-05-04 | 2004-11-03 | $7700.00 | Window Closed / Lapsed |