US5246799A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of removing excess material, for repairing phase-shifting lithographic masks
Assignee: Nokia Bell Labs
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Filing: 1991-09-20
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Granted: 1993-09-21
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Expires: 2011-09-20
Abstract
Abstract A defect in the form of excess material, located in a trench region at a major surface of a phase-shifting mask, is removed by spinning on the major surface a planarization layer for which dry-etching conditions exist at which it anisotropically etches at the same rate as that of the excess material. Then the planarization layer is dry-etched under those conditions, using a patterned protective masking layer, such as chrome, having an aperture overlying the defect in the trench. This aperture need not be precisely laterally aligned with the defect (unless the defect extends to an edge of the trench). A plurality of such defects can be simultaneously removed. Likewise, defects located on plateau regions of the mask can be repaired.
Inventors
- 👤 Christophe Pierrat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:03
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/68; G03F1/72; G03F1/26; G03F1/30
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
154 words
A method of repairing a phase-shifting lithographic mask, the mask having a substrate, the substrate having a trench region and a plateau region each of which has a substantially planar top surface except in a defect region located in one of the trench or plateau regions where excess material is present, comprising the steps of (a) forming a first layer having a substantially planar surface overlying at least the one region, the first layer having a portion, overlying at least the lateral extent of the defect region, that is characterized by etching conditions at which it etches at substantially the same rate as that of the excess material; and (b) etching through the portion of the first layer at the etching conditions until the etching reaches the level of the top surface of the one region, whereby the excess material is removed, and whereby the entire surface of the one region is substantially planar.
Claim 2
Independent Claim
154 words
A method of repairing a phase-shifting lithographic mask, the mask having a substrate, the substrate having a trench region and a plateau region each of which has a substantially planar top surface except in a defect region located in one of the trench or plateau regions where excess material is present, comprising the steps of (a) forming a first layer having a substantially planar surface overlying at least the one region, the first layer having a portion, overlying at least the lateral extent of the defect region, that is characterized by etching conditions at which it etches at substantially the same rate as that of the excess material; and (b) etching through the portion of the first layer at the etching conditions until the etching reaches the level of the top surface of the one region, whereby the excess material is removed, and whereby the entire surface of the one region is substantially planar.
Claim 3
Dependent Claim
66 words
The method of claim 1 in which prior to the etching, a second layer is formed on the top surface of the first layer, and an aperture is formed in the second layer overlying at least the entire lateral extent of the defect region, the second layer being resistant to the etching, whereby the aperture in the second layer defines the portion of the first layer.
Claim 4
Dependent Claim
19 words
The method of claim 2 in which the excess material has the same composition as that of the substrate.
Claim 5
Dependent Claim
18 words
The method of claim 2 further comprising the step of two-dimensionally inspecting the mask for the defect region.
Claim 6
Dependent Claim
14 words
The method of claim 2 in which the first layer is essentially a polymer.
Claim 7
Dependent Claim
19 words
The method of claim 5 in which the excess material has the same composition as that of the substrate.
Claim 8
Dependent Claim
15 words
The method of claim 2 in which the second layer comprises a layer of metal.
Claim 9
Dependent Claim
23 words
The method of claim 2 further comprising the step of removing the remnants of the first and second layers subsequent to step (b).
Claim 10
Dependent Claim
12 words
The method of claim 2 in which the composition is essentially quartz.
Claim 11
Dependent Claim
14 words
The method of claim 9 in which the first layer is essentially a polymer.
Claim 12
Dependent Claim
19 words
The method of claim 9 in which the excess material has the same composition as that of the substrate.
Claim 13
Dependent Claim
13 words
The method of claim 1 in which the second layer comprises a metal.
Claim 14
Dependent Claim
22 words
The method of claim 1 further comprising the step of two-dimensionally inspecting the mask for the defect region prior to step (a).
Claim 15
Dependent Claim
19 words
The method of claim 1 in which the excess material has the same composition as that of the substrate.
Claim 16
Dependent Claim
14 words
The method of claim 1 in which the first layer is essentially a polymer.
Claim 17
Dependent Claim
19 words
The method of claim 15 in which the excess material has the same composition as that of the substrate.
Claim 18
Dependent Claim
12 words
The method of claim 16 in which the composition is essentially quartz.
Claim 19
Dependent Claim
21 words
The method of claim 1 further comprising the step of removing the remnants of the first layer subsequent to step (b).
Claim 20
Dependent Claim
103 words
A photolithographic method including the steps of: (a) repairing a phase-shifting in accordance with the steps recited in claim 18; (b) directing the optical radiation onto the mask, and focusing the radiation propagating through the mask onto a photoresist layer located on a major surface of a wafer, or on a layer of material located on a major surface of a wafer; (c) developing the photoresist layer, whereby an edge feature is formed therein; and (d) defining a feature at the major surface of the wafer or in the layer of material, respectively, in accordance with the edge feature in the photoresist layer.
Claim 21
Dependent Claim
104 words
A photolithographic method including the steps of: (a) repairing a phase-shifting mask in accordance with the steps recited in claim 8; (b) directing the optical radiation onto the mask, and focusing the radiation propagating through the mask onto a photoresist layer located on a major surface of a wafer, or on a layer of material located on a major surface of a wafer; (c) developing the photoresist layer, whereby an edge feature is formed therein; and (d) defining a feature at the major surface of the wafer or in the layer of material, respectively, in accordance with the edge feature in the photoresist layer.
References Cited (Backward Citations)
US4906326A
Cited
US5085957A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-09-20 | 1997-03-22 | 1997-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-20 | 2001-03-22 | 2001-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-20 | 2005-03-22 | 2005-09-21 | $7700.00 | Window Closed / Lapsed |