US5851701A
Expired / Lapsed
US
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Atom lithographic mask having diffraction grating and attenuated phase shifters
Assignee: Micron Technology Inc
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Filing: 1997-04-01
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Granted: 1998-12-22
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Expires: 2017-04-01
Abstract
Abstract An ATOM lithographic mask includes a transparent substrate having a pattern of attenuated phase shifters and a diffraction grating aligned with the attenuated phase shifters. The attenuated phase shifters form the primary mask pattern, while the diffraction grating diffracts exposure energy directed through the mask to provide off axis illumination for the attenuated phase shifters. The diffraction grating includes chromeless phase shifters formed using an additive or subtractive process. Both the attenuated phase shifters and diffraction grating can be formed as simple line-space patterns or in other patterns as required. In an alternate embodiment the diffraction grating is formed on a separate mask.
Inventors
- 👤 J. Brett Rolson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:04
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/26; G03F1/32; G03F1/50; G03F7/00; G03F7/70; G03F7/70058; G03F7/70091; G03F7/7015; G03F7/70158; G03F7/70216; G03F7/70283
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
92 words
A lithographic mask comprising: a transparent substrate; a pattern of attenuated phase shifters proximate to a first side of the substrate, the attenuated phase shifters comprising an absorbing layer configured to absorb and phase shift an exposure energy directed through the mask; and a diffraction grating formed proximate to a second side of the substrate in alignment with the pattern of attenuated phase shifters and configured to diffract the exposure energy to illuminate the attenuated phase shifters and print a plurality of features corresponding to the attenuated phase shifters on a target.
Claim 2
Dependent Claim
92 words
A lithographic mask comprising: a transparent substrate; a pattern of attenuated phase shifters proximate to a first side of the substrate, the attenuated phase shifters comprising an absorbing layer configured to absorb and phase shift an exposure energy directed through the mask; and a diffraction grating formed proximate to a second side of the substrate in alignment with the pattern of attenuated phase shifters and configured to diffract the exposure energy to illuminate the attenuated phase shifters and print a plurality of features corresponding to the attenuated phase shifters on a target.
Claim 3
Dependent Claim
33 words
The lithographic mask of claim 1 wherein the diffraction grating comprises a plurality of phase shift grooves formed in the substrate to a depth to provide a phase shift for the exposure energy.
Claim 4
Dependent Claim
24 words
The lithographic mask of claim 1 wherein the diffraction grating comprises a plurality of additive phase shifters comprising a transparent material on the substrate.
Claim 5
Dependent Claim
25 words
The lithographic mask of claim 1 wherein the attenuated phase shifters are configured to phase shift the exposure energy by π or odd multiple thereof.
Claim 6
Dependent Claim
19 words
The lithographic mask of claim 1 wherein the attenuated phase shifters comprise a dielectric layer on the absorbing layer.
Claim 7
Dependent Claim
105 words
A lithographic mask comprising: a transparent substrate; a plurality of attenuated phase shifters formed proximate to a first side of the substrate, the attenuated phase shifters comprising an absorbing material configured to absorb and phase shift an exposure energy directed through the mask; and a plurality of diffraction phase shifters formed proximate to a second side of the substrate in alignment with the attenuated phase shifters, the diffraction phase shifters configured to phase shift and diffract the exposure energy to provide off axis illumination for the attenuated phase shifters and to project a pattern of features corresponding to the attenuated phase shifters on a target.
Claim 8
Dependent Claim
105 words
A lithographic mask comprising: a transparent substrate; a plurality of attenuated phase shifters formed proximate to a first side of the substrate, the attenuated phase shifters comprising an absorbing material configured to absorb and phase shift an exposure energy directed through the mask; and a plurality of diffraction phase shifters formed proximate to a second side of the substrate in alignment with the attenuated phase shifters, the diffraction phase shifters configured to phase shift and diffract the exposure energy to provide off axis illumination for the attenuated phase shifters and to project a pattern of features corresponding to the attenuated phase shifters on a target.
Claim 9
Dependent Claim
20 words
The lithographic mask of claim 1 wherein the attenuated phase shifters and the diffraction phase shifters comprise line space patterns.
Claim 10
Dependent Claim
35 words
The lithographic mask of claim 1 wherein the diffraction phase shifters comprise a plurality of grooves etched into the substrate to a depth selected to provide a phase shift of π or odd multiple thereof.
Claim 11
Dependent Claim
34 words
The lithographic mask of claim 1 wherein the diffraction phase shifters comprise a phase layer deposited on the substrate to a thickness selected to provide a phase shift of π or odd multiple thereof.
Claim 12
Dependent Claim
126 words
A lithographic mask comprising: a transparent substrate having a first side and a second opposing side; a mask pattern on the first side of the substrate comprising a plurality of attenuated phase shifters, each phase shifter comprising an absorbing layer configured to absorb and phase shift an exposure energy passing therethrough by an amount equal to π or odd multiple thereof; and a grating pattern formed on the second side of the substrate in alignment with the mask pattern, the grating pattern comprising a plurality of parallel spaced grooves etched into the substrate to a depth selected to phase shift and diffract the exposure energy passing there through to provide off axis illumination of the attenuated phase shifters for printing the mask pattern on a target.
Claim 13
Dependent Claim
126 words
A lithographic mask comprising: a transparent substrate having a first side and a second opposing side; a mask pattern on the first side of the substrate comprising a plurality of attenuated phase shifters, each phase shifter comprising an absorbing layer configured to absorb and phase shift an exposure energy passing therethrough by an amount equal to π or odd multiple thereof; and a grating pattern formed on the second side of the substrate in alignment with the mask pattern, the grating pattern comprising a plurality of parallel spaced grooves etched into the substrate to a depth selected to phase shift and diffract the exposure energy passing there through to provide off axis illumination of the attenuated phase shifters for printing the mask pattern on a target.
Claim 14
Dependent Claim
27 words
The mask of claim 10 wherein the absorbing layer comprises a material selected from the group consisting of molybdenum silicide, and mixtures of chrome nitrogen and oxygen.
Claim 15
Dependent Claim
24 words
The mask of claim 10 wherein the depth of the grooves is selected to provide a phase shift of π or odd multiple thereof.
Claim 16
Dependent Claim
26 words
The mask of claim 10 wherein the primary mask pattern comprises a first line space pattern and the grating pattern comprises a second line space pattern.
Claim 17
Dependent Claim
30 words
The mask of claim 10 wherein a pitch of the grating pattern is selected to provide a desired resolution and depth of focus during illumination of the primary mask pattern.
Claim 18
Dependent Claim
112 words
A lithographic mask comprising: a transparent substrate having a first side and a second side; a plurality of attenuated phase shifters on the first side of the substrate forming a mash pattern, the attenuated phase shifters comprising an absorbing layer and a dielectric layer configured to absorb and phase shift an exposure energy directed through the mask; and a plurality of chase shifters on the second side of the substrate in alignment with the attenuated phase shifters, the phase shifters comprising a transparent material deposited on the substrate to a thickness selected to phase shift the exposure energy for illuminating the attenuated phase shifters for projecting the mask pattern on a target.
Claim 19
Dependent Claim
112 words
A lithographic mask comprising: a transparent substrate having a first side and a second side; a plurality of attenuated phase shifters on the first side of the substrate forming a mash pattern, the attenuated phase shifters comprising an absorbing layer and a dielectric layer configured to absorb and phase shift an exposure energy directed through the mask; and a plurality of chase shifters on the second side of the substrate in alignment with the attenuated phase shifters, the phase shifters comprising a transparent material deposited on the substrate to a thickness selected to phase shift the exposure energy for illuminating the attenuated phase shifters for projecting the mask pattern on a target.
Claim 20
Dependent Claim
24 words
The lithographic mask of claim 15 wherein the attenuated phase shifters are configured to provide a phase shift of π or whole multiple thereof.
Claim 21
Dependent Claim
15 words
The lithographic mask of claim 15 wherein the mask pattern comprises a line space pattern.
Claim 22
Dependent Claim
28 words
The lithographic mask of claim 15 wherein the absorbing layer comprises a material selected from the group consisting of molybdenum silicide and mixtures of chrome nitrogen and oxygen.
Claim 23
Dependent Claim
29 words
The lithographic mask of claim 15 wherein a pitch of the attenuated phase shifters is selected to provide a desired resolution and depth of focus for the mask pattern.
Claim 24
Dependent Claim
26 words
The lithographic mask of claim 15 wherein the thickness of the phase shifters is selected to provide a phase shift of π or odd multiple thereof.
Claim 25
Dependent Claim
112 words
A lithographic mask comprising: a substrate having a first side and a second opposing side; a mask pattern on the first side of the substrate comprising a plurality of attenuated phase shifters, each attenuated phase shifter comprising an absorbing layer configured to absorb and phase shift an exposure energy directed through the mask; and a grating pattern formed on the second side of the substrate in alignment with the mask pattern, the grating pattern comprising a plurality of parallel spaced phase shift grooves etched into the substrate to a depth to diffract and phase shift the exposure energy for illuminating the attenuated phase shifters and protecting the mask pattern onto a target.
Claim 26
Dependent Claim
112 words
A lithographic mask comprising: a substrate having a first side and a second opposing side; a mask pattern on the first side of the substrate comprising a plurality of attenuated phase shifters, each attenuated phase shifter comprising an absorbing layer configured to absorb and phase shift an exposure energy directed through the mask; and a grating pattern formed on the second side of the substrate in alignment with the mask pattern, the grating pattern comprising a plurality of parallel spaced phase shift grooves etched into the substrate to a depth to diffract and phase shift the exposure energy for illuminating the attenuated phase shifters and protecting the mask pattern onto a target.
Claim 27
Dependent Claim
22 words
The mask of claim 21 wherein the substrate comprises a material selected from the group consisting of quartz and silica based glass.
Claim 28
Dependent Claim
27 words
The mask of claim 21 wherein the absorbing layer comprises a material selected from the group consisting of molybdenum silicide, and mixtures of chrome nitrogen and oxygen.
Claim 29
Dependent Claim
44 words
The mask of claim 21 wherein the depth is selected to provide a phase shift of π or odd multiple thereof for the exposure energy passing through the phase shift grooves relative to the exposure energy passing through a full thickness of the substrate.
Claim 30
Independent Claim
90 words
A method for fabricating a lithographic mask comprising: providing a transparent substrate having a first side and an opposing second side; forming a plurality of attenuated phase shifters on the first side, the attenuated phase shifters comprising an absorbing layer configured to absorb and phase shift an exposure energy transmitted through the mask during a lithographic process; and forming a plurality of phase shifters on the second side, the phase shifters configured to phase shift and diffract the exposure energy to provide off axis illumination for the attenuated phase shifters.
Claim 31
Independent Claim
90 words
A method for fabricating a lithographic mask comprising: providing a transparent substrate having a first side and an opposing second side; forming a plurality of attenuated phase shifters on the first side, the attenuated phase shifters comprising an absorbing layer configured to absorb and phase shift an exposure energy transmitted through the mask during a lithographic process; and forming a plurality of phase shifters on the second side, the phase shifters configured to phase shift and diffract the exposure energy to provide off axis illumination for the attenuated phase shifters.
Claim 32
Dependent Claim
30 words
The method of claim 25 wherein forming the phase shifters comprise grooves etched in the substrate to a depth for producing a phase shift of π or odd multiple thereof.
Claim 33
Dependent Claim
31 words
The method of claim 25 wherein the phase shifters comprise a transparent phase layer on the substrate to a thickness for producing a phase shift of π or odd multiple thereof.
Claim 34
Dependent Claim
17 words
The method of claim 25 further comprising forming a transparent dielectric layer on the attenuated phase shifters.
Claim 35
Dependent Claim
22 words
The method as claimed in claim 25 further comprising forming a transparent dielectric layer between the attenuated phase shifters and the substrate.
Claim 36
Dependent Claim
109 words
A lithographic system comprising: an exposure source for providing an exposure energy for patterning a layer of resist on a target; a mask configured to transmit the exposure energy onto the target; the mask comprising a plurality of attenuated phase shifters, each attenuated phase shifter comprising an absorbing layer configured to absorb and phase shift the exposure energy transmitted through the mask; and a diffraction grating formed on the mask in alignment with the attenuated phase shifters, the diffraction grating comprising a plurality of phase shifters configured to diffract the exposure energy to provide off axis illumination for the attenuated phase shifters during patterning of the layer of resist.
Claim 37
Dependent Claim
109 words
A lithographic system comprising: an exposure source for providing an exposure energy for patterning a layer of resist on a target; a mask configured to transmit the exposure energy onto the target; the mask comprising a plurality of attenuated phase shifters, each attenuated phase shifter comprising an absorbing layer configured to absorb and phase shift the exposure energy transmitted through the mask; and a diffraction grating formed on the mask in alignment with the attenuated phase shifters, the diffraction grating comprising a plurality of phase shifters configured to diffract the exposure energy to provide off axis illumination for the attenuated phase shifters during patterning of the layer of resist.
Claim 38
Dependent Claim
14 words
The system of claim 30 wherein each phase shifter comprises a phase shift groove.
Claim 39
Dependent Claim
13 words
The system of claim 30 wherein each phase shifter comprises a phase layer.
Claim 40
Dependent Claim
14 words
The system of claim 30 wherein each attenuated phase shifter comprises a dielectric layer.
Claim 41
Dependent Claim
128 words
A lithographic system comprising: an exposure source for providing an exposure energy; a mask comprising a transparent substrate configured to project the exposure energy onto a target; a plurality of attenuated phase shifters formed proximate to a first side of the substrate, each attenuated phase shifter comprising an absorbing layer configured to absorb and phase shift the exposure energy by an amount equal to π or odd multiple thereof; and a plurality of diffraction phase shifters formed proximate to a second side of the substrate in alignment with the attenuated phase shifters, the diffraction phase shifters comprising a diffraction grating configured to diffract the exposure energy to provide off axis illumination for the attenuated phase shifters for printing features corresponding to the attenuated phase shifters on the target.
Claim 42
Dependent Claim
128 words
A lithographic system comprising: an exposure source for providing an exposure energy; a mask comprising a transparent substrate configured to project the exposure energy onto a target; a plurality of attenuated phase shifters formed proximate to a first side of the substrate, each attenuated phase shifter comprising an absorbing layer configured to absorb and phase shift the exposure energy by an amount equal to π or odd multiple thereof; and a plurality of diffraction phase shifters formed proximate to a second side of the substrate in alignment with the attenuated phase shifters, the diffraction phase shifters comprising a diffraction grating configured to diffract the exposure energy to provide off axis illumination for the attenuated phase shifters for printing features corresponding to the attenuated phase shifters on the target.
Claim 43
Dependent Claim
18 words
The system of claim 34 wherein each attenuated phase shifter comprises a dielectric layer on the absorbing layer.
Claim 44
Dependent Claim
21 words
The system of claim 34 wherein each diffraction phase shifter comprises a groove etched into the substrate to a selected depth.
Claim 45
Dependent Claim
23 words
The system of claim 34 wherein each diffraction phase shifter comprises a transparent chase layer deposited on the substrate to a selected thickness.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-12-21 | 2002-06-22 | 2002-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-21 | 2006-06-22 | 2006-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-21 | 2010-06-22 | 2010-12-22 | $7700.00 | Window Closed / Lapsed |