US5766829A
Expired / Lapsed
US
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Method of phase shift lithography
Assignee: Micron Technology Inc
•
Filing: 1995-05-30
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Granted: 1998-06-16
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Expires: 2015-05-30
Abstract
Abstract A method of phase shift lithography includes forming a chromeless phase shift reticle with a pattern of parallel, spaced phase shifters. The phase shift reticle is placed between an exposure source (e.g., UV light) and a substrate having a layer resist formed thereon. Following an initial exposure, the phase shift reticle is rotated and the substrate is exposed a second time. The resist is then developed to form features in areas of resist that have not been exposed. These areas correspond to the projected points of intersection of the phase shifters. Using a positive tone resist, solid resist features are formed. These solid features can be used as mask blocks for etching the substrate to form field emitter sites for a field emission display. Using a negative tone resist, open areas are formed in the resist and can be used to deposit a material on the substrate such as a contacts for a semiconductor structure. The method of the invention can also be implemented using two different reticles with intersecting patterns or using a single reticle having intersecting phase shift areas.
Inventors
- 👤 David A. Cathey, Jr.
- 👤 J. Brett Rolfson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:56
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/26; G03F1/34; G03F7/00; G03F7/70; G03F7/70216; G03F7/70283; G03F7/70425; G03F7/70466
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
104 words
A method of phase shift lithography comprising: providing a target with a layer of resist thereon; providing a first and a second chromeless phase shift pattern on a same reticle, said first and second patterns comprising parallel spaced phase shifters formed to project an intersecting pattern on the target; directing an exposure energy through the first pattern to form an exposure pattern on the resist; moving the reticle or the target to align the second pattern with the exposure pattern; directing the exposure energy through the second pattern; and developing the resist to form features corresponding to selected areas of resist that remain unexposed.
Claim 2
Independent Claim
104 words
A method of phase shift lithography comprising: providing a target with a layer of resist thereon; providing a first and a second chromeless phase shift pattern on a same reticle, said first and second patterns comprising parallel spaced phase shifters formed to project an intersecting pattern on the target; directing an exposure energy through the first pattern to form an exposure pattern on the resist; moving the reticle or the target to align the second pattern with the exposure pattern; directing the exposure energy through the second pattern; and developing the resist to form features corresponding to selected areas of resist that remain unexposed.
Claim 3
Dependent Claim
21 words
The method as claimed in claim 1 wherein the resist comprises a positive tone resist and the features comprise resist islands.
Claim 4
Dependent Claim
19 words
The method as claimed in claim 1 wherein developing the resist forms a resist mask for etching the target.
Claim 5
Dependent Claim
26 words
The method as claimed in claim 3 further comprising etching the target using the resist mask to form field emitter sites for a field emission display.
Claim 6
Dependent Claim
21 words
The method as claimed in claim 1 wherein the resist comprises a negative tone resist and the features comprise open areas.
Claim 7
Dependent Claim
22 words
The method as claimed in claim 1 wherein developing the resist forms a resist mask for depositing a material onto the target.
Claim 8
Dependent Claim
17 words
The method as claimed in claim 6 wherein depositing the material forms contacts for a semiconductor device.
Claim 9
Dependent Claim
15 words
The method as claimed in claim 1 wherein the features are generally circular in shape.
Claim 10
Dependent Claim
26 words
The method as claimed in claim 1 wherein developing the resist forms a resist mask for etching the target to form openings for a Spindt cathode.
Claim 11
Independent Claim
106 words
A method of phase shift lithography comprising: providing a target with a layer of resist thereon; providing a chromeless phase shift reticle comprising first and second phase shift regions formed to project an intersecting pattern on the target; directing an exposure energy through the first phase shift region to form an exposure pattern on the resist; moving the target or the reticle to align the second phase shift region with the exposure pattern; directing exposure energy through the second phase shift region; and developing the resist to form features corresponding to areas unexposed by the exposure energy passing through the first and second phase shift regions.
Claim 12
Independent Claim
106 words
A method of phase shift lithography comprising: providing a target with a layer of resist thereon; providing a chromeless phase shift reticle comprising first and second phase shift regions formed to project an intersecting pattern on the target; directing an exposure energy through the first phase shift region to form an exposure pattern on the resist; moving the target or the reticle to align the second phase shift region with the exposure pattern; directing exposure energy through the second phase shift region; and developing the resist to form features corresponding to areas unexposed by the exposure energy passing through the first and second phase shift regions.
Claim 13
Dependent Claim
21 words
The method as claimed in claim 10 wherein the resist comprises a positive tone resist and the features comprise resist islands.
Claim 14
Dependent Claim
23 words
The method as claimed in claim 10 wherein the resist comprises a negative tone resist and the features comprise openings in the resist.
Claim 15
Dependent Claim
18 words
The method as claimed in claim 10 wherein the target comprises a baseplate of a field emission display.
Claim 16
Dependent Claim
14 words
The method as claimed in claim 10 wherein the target comprises a semiconducting substrate.
Claim 17
Dependent Claim
15 words
The method as claimed in claim 10 wherein the features are generally circular in shape.
Claim 18
Dependent Claim
20 words
The method as claimed in claim 10 wherein the features are generally circular in shape with a sub micron diameter.
References Cited (Backward Citations)
US3755704A
Cited
US3812559A
Cited
US3665241A
Cited
US5079113A
Cited
US5045417A
Cited
US5290647A
Cited
US5126220A
Cited
US5328807A
Cited
US5255035A
Cited
US5194344A
Cited
US5217830A
Cited
US5194346A
Cited
US5194345A
Cited
US5318868A
Cited
US5316878A
Cited
US5240796A
Cited
US5324600A
Cited
US5208125A
Cited
US5281500A
Cited
US5288568A
Cited
US5382483A
Cited
US5302238A
Cited
US5308741A
Cited
US5439764A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-06-15 | 2001-12-15 | 2002-06-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-06-15 | 2005-12-15 | 2006-06-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-06-15 | 2009-12-15 | 2010-06-16 | $7700.00 | Window Closed / Lapsed |