US5695896A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for fabricating a phase shifting mask
Assignee: Micron Technology Inc
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Filing: 1995-12-04
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Granted: 1997-12-09
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Expires: 2015-12-04
Abstract
Abstract A simplified process for forming a phase shifting mask is disclosed. A chrome layer is formed on a transparent substrate and patterned. A resist layer is patterned to define the phase shifting areas and the substrate is dry etched to a first predetermined depth, stripped and cleaned. Another resist layer is patterned to define the phase shifting areas and the substrate is dry etched a second predetermined depth, stripped and cleaned. A further resist layer is patterned to define the phase shifting areas and the substrate is wet etched a third predetermined depth, stripped and cleaned. The sum of the three predetermined depths is such that it corresponds to a 180° phase shift of light passing through the substrate. The third predetermined depth is at least about one third of the total depth.
Inventors
- 👤 Christophe Pierrat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:22
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/26; G03F1/30
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
179 words
A process for fabricating a phase shifting mask comprising: patterning an opaque layer on a transparent mask substrate to form a desired pattern; coating said substrate with a resist and creating a first phase shifting pattern on said substrate; dry etching said substrate through said first pattern to a first predetermined depth; removing said resist forming said first phase shifting pattern and cleaning said substrate; coating said substrate with a resist and creating a second phase shifting pattern on said substrate; dry etching said substrate through said second pattern to a second predetermined depth; removing said resist forming said second phase shifting pattern and cleaning said substrate; coating said substrate with a resist and creating a third phase shifting pattern on said substrate; wet etching said substrate through said third pattern to a third predetermined depth; and removing said resist forming said third phase shifting pattern and cleaning said substrate; wherein the sum of said first, second and third predetermined depths creates a pattern in said substrate corresponding to a 180° phase shift of light passing through said substrate.
Claim 2
Dependent Claim
179 words
A process for fabricating a phase shifting mask comprising: patterning an opaque layer on a transparent mask substrate to form a desired pattern; coating said substrate with a resist and creating a first phase shifting pattern on said substrate; dry etching said substrate through said first pattern to a first predetermined depth; removing said resist forming said first phase shifting pattern and cleaning said substrate; coating said substrate with a resist and creating a second phase shifting pattern on said substrate; dry etching said substrate through said second pattern to a second predetermined depth; removing said resist forming said second phase shifting pattern and cleaning said substrate; coating said substrate with a resist and creating a third phase shifting pattern on said substrate; wet etching said substrate through said third pattern to a third predetermined depth; and removing said resist forming said third phase shifting pattern and cleaning said substrate; wherein the sum of said first, second and third predetermined depths creates a pattern in said substrate corresponding to a 180° phase shift of light passing through said substrate.
Claim 3
Dependent Claim
33 words
A process for fabricating a phase shifting mask as defined in claim 1 wherein said wet etching step comprises etching said substrate with a BOE 7:1, using a buffered HF in water solution.
Claim 4
Dependent Claim
38 words
A process for fabricating a phase shifting mask as defined in claim 1 wherein said first and second predetermined depths are substantially equal and said third predetermined depth is greater than or equal to said first predetermined depth.
Claim 5
Dependent Claim
19 words
A process for fabricating a phase shifting mask as defined in claim 1 wherein said mask substrate comprises quartz.
Claim 6
Dependent Claim
25 words
A process for fabricating a phase shifting mask as defined in claim 1 wherein said third predetermined depth is between about 50 and 150 nm.
Claim 7
Dependent Claim
25 words
A process for fabricating a phase shifting mask as defined in claim 5 wherein said third predetermined depth is between about 90 and 150 nm.
Claim 8
Dependent Claim
22 words
A process for fabricating a phase shifting mask as defined in claim 6 wherein said third predetermined depth is about 150 nm.
Claim 9
Dependent Claim
11 words
A phase shifting mask produced by the process of claim 1.
Claim 10
Dependent Claim
194 words
A process for fabricating a phase shifting mask comprising: patterning an opaque layer on a transparent mask substrate to form a desired pattern; coating said substrate with a resist and creating a first phase shifting pattern on said substrate; dry etching said substrate through said first pattern to a first predetermined depth; removing said resist forming said first phase shifting pattern and cleaning said substrate; coating said substrate with a resist and creating a second phase shifting pattern on said substrate; dry etching said substrate through said second pattern to a second predetermined depth; removing said resist forming said second phase shifting pattern and cleaning said substrate; coating said substrate with a resist and creating a third phase shifting pattern on said substrate; wet etching said substrate through said third pattern to a third predetermined depth; and removing said resist forming said third phase shifting pattern and cleaning said substrate; wherein the sum of said first, second and third predetermined depths creates a pattern in said substrate corresponding to a 180° phase shift of light passing through said substrate and said third predetermined depth is at least about one third of the total depth.
Claim 11
Dependent Claim
194 words
A process for fabricating a phase shifting mask comprising: patterning an opaque layer on a transparent mask substrate to form a desired pattern; coating said substrate with a resist and creating a first phase shifting pattern on said substrate; dry etching said substrate through said first pattern to a first predetermined depth; removing said resist forming said first phase shifting pattern and cleaning said substrate; coating said substrate with a resist and creating a second phase shifting pattern on said substrate; dry etching said substrate through said second pattern to a second predetermined depth; removing said resist forming said second phase shifting pattern and cleaning said substrate; coating said substrate with a resist and creating a third phase shifting pattern on said substrate; wet etching said substrate through said third pattern to a third predetermined depth; and removing said resist forming said third phase shifting pattern and cleaning said substrate; wherein the sum of said first, second and third predetermined depths creates a pattern in said substrate corresponding to a 180° phase shift of light passing through said substrate and said third predetermined depth is at least about one third of the total depth.
Claim 12
Dependent Claim
33 words
A process for fabricating a phase shifting mask as defined in claim 9 wherein said wet etching step comprises etching said substrate with a BOE 7:1, using a buffered HF in water solution.
Claim 13
Dependent Claim
19 words
A process for fabricating a phase shifting mask as defined in claim 9 wherein said mask substrate comprises quartz.
Claim 14
Dependent Claim
25 words
A process for fabricating a phase shifting mask as defined in claim 9 wherein said third predetermined depth is between about 50 and 150 nm.
Claim 15
Dependent Claim
25 words
A process for fabricating a phase shifting mask as defined in claim 12 wherein said third predetermined depth is between about 90 and 150 nm.
Claim 16
Dependent Claim
22 words
A process for fabricating a phase shifting mask as defined in claim 13 wherein said third predetermined depth is about 150 nm.
Claim 17
Dependent Claim
11 words
A phase shifting mask produced by the process of claim 9.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-12-08 | 2001-06-09 | 2001-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-08 | 2005-06-09 | 2005-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-08 | 2009-06-09 | 2009-12-09 | $7700.00 | Window Closed / Lapsed |