US6106979A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Use of attenuating phase-shifting mask for improved printability of clear-field patterns
Assignee: Micron Technology Inc
•
Filing: 1997-12-30
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Granted: 2000-08-22
•
Expires: 2017-12-30
Abstract
Abstract An improved photolithographic method employs a pattern of subresolution openings to enhance the printability of clear-field patterns. Incorporating a subresolution opening along the edges of the transmission areas prevents the printing of side lobe light and enables incorporation of a positive bias in the clear-field pattern. This in turn increases the lithographic process latitudes. The photomask must be significantly overexposed as a result of using a positive bias. To compensate for the impact of increased exposure on large transmission areas and avoid degradation of the corresponding resist, a pattern of subresolution openings is incorporated in the large transmission areas. The size and orientation of the subresolution areas creates a diffraction grating effect, reducing the exposure of the area under each transmission area.
Inventors
- 👤 Christophe Pierrat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:02
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/26; G03F1/32
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
52 words
A method for manufacturing a photomask, comprising: preparing a transparent plate; and forming one or more transmission areas intermingled with one or more transparent areas, comprising: depositing attenuating phase-shifting material on the transparent plate in the transmission areas; and forming a plurality of subresolution openings in the one or more transmission areas.
Claim 2
Independent Claim
52 words
A method for manufacturing a photomask, comprising: preparing a transparent plate; and forming one or more transmission areas intermingled with one or more transparent areas, comprising: depositing attenuating phase-shifting material on the transparent plate in the transmission areas; and forming a plurality of subresolution openings in the one or more transmission areas.
Claim 3
Dependent Claim
21 words
The method of claim 1, wherein forming one or more transmission areas further comprises the step of forming a clear-field pattern.
Claim 4
Dependent Claim
22 words
The method of claim 2, wherein forming one or more transmission areas further comprises positively biasing the one or more transmission areas.
Claim 5
Dependent Claim
30 words
The method of claim 1, wherein forming the pattern of subresolution openings further comprises forming openings parallel to and inside each edge of the one or more opaque transmission areas.
Claim 6
Dependent Claim
21 words
The method of claim 1, wherein forming the pattern of subresolution openings further comprises forming a grid of regularly spaced openings.
Claim 7
Independent Claim
85 words
A method for manufacturing a photomask comprising: preparing a transparent plate; and forming a positively biased clear field pattern on the transparent plate comprising one or more transmission areas intermingled with one or more transparent areas, comprising: depositing attenuating phase-shifting material on the transparent plate in the transmission areas; forming a plurality of subresolution openings parallel to and inside each edge of the one or more transmission areas; and forming a grid of subresolution openings within a plurality of the one or more transmission areas.
Claim 8
Independent Claim
85 words
A method for manufacturing a photomask comprising: preparing a transparent plate; and forming a positively biased clear field pattern on the transparent plate comprising one or more transmission areas intermingled with one or more transparent areas, comprising: depositing attenuating phase-shifting material on the transparent plate in the transmission areas; forming a plurality of subresolution openings parallel to and inside each edge of the one or more transmission areas; and forming a grid of subresolution openings within a plurality of the one or more transmission areas.
Claim 9
Dependent Claim
57 words
A photomask, comprising: a transparent plate; and a pattern of attenuating material deposited on the transparent plate, the pattern including: one or more transparent areas; and one or more transmission areas intermingled with the one or more transparent areas, one or more of each of the one or more transmission areas comprising a pattern of subresolution openings.
Claim 10
Dependent Claim
57 words
A photomask, comprising: a transparent plate; and a pattern of attenuating material deposited on the transparent plate, the pattern including: one or more transparent areas; and one or more transmission areas intermingled with the one or more transparent areas, one or more of each of the one or more transmission areas comprising a pattern of subresolution openings.
Claim 11
Dependent Claim
15 words
The photomask of claim 7, wherein the pattern of attenuating material is a clear-field pattern.
Claim 12
Dependent Claim
12 words
The photomask of claim 8, wherein the transmission areas are positively biased.
Claim 13
Dependent Claim
26 words
The photomask of claim 9, wherein the pattern of subresolution openings further comprises subresolution openings parallel to each edge of the one or more transmission areas.
Claim 14
Dependent Claim
19 words
The photomask of claim 9, wherein the pattern of subresolution openings further comprises a grid of regularly spaced openings.
Claim 15
Dependent Claim
51 words
A photomask, comprising: a transparent plate; and a clear-field pattern of attenuating material deposited on the transparent plate, the pattern including: one or more transparent areas; and one or more transmission areas intermingled with one or more transparent areas, the one or more transmission areas comprising a pattern of subresolution openings.
Claim 16
Dependent Claim
51 words
A photomask, comprising: a transparent plate; and a clear-field pattern of attenuating material deposited on the transparent plate, the pattern including: one or more transparent areas; and one or more transmission areas intermingled with one or more transparent areas, the one or more transmission areas comprising a pattern of subresolution openings.
Claim 17
Dependent Claim
12 words
The photomask of claim 12, wherein the transmission areas are positively biased.
Claim 18
Dependent Claim
25 words
The photomask of claim 13, wherein the pattern of subresolution openings comprises subresolution openings parallel to each edge of the one or more transmission areas.
Claim 19
Dependent Claim
18 words
The photomask of claim 13, wherein the pattern of subresolution openings comprises a grid of regularly spaced openings.
Claim 20
Dependent Claim
79 words
A photomask, comprising: a transparent plate; and a positively biased clear-field pattern of attenuating material deposited on the transparent plate, the pattern comprising: one or more transparent areas; and one or more transmission areas intermingled with one or more transparent areas, the one or more transmission areas including: a pattern of subresolution openings parallel to and inside each edge of the one or more transmission areas; and a pattern of subresolution openings comprising a grid of regularly spaced openings.
Claim 21
Dependent Claim
79 words
A photomask, comprising: a transparent plate; and a positively biased clear-field pattern of attenuating material deposited on the transparent plate, the pattern comprising: one or more transparent areas; and one or more transmission areas intermingled with one or more transparent areas, the one or more transmission areas including: a pattern of subresolution openings parallel to and inside each edge of the one or more transmission areas; and a pattern of subresolution openings comprising a grid of regularly spaced openings.
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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) | 2003-08-22 | 2004-02-21 | 2004-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-08-22 | 2008-02-21 | 2008-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-08-22 | 2012-02-21 | 2012-08-22 | $7700.00 | Window Closed / Lapsed |