US4548883A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Correction of lithographic masks
Assignee: Nokia Bell Labs
•
Filing: 1983-05-31
•
Granted: 1985-10-22
•
Expires: 2003-05-31
Abstract
Abstract A lithographic mask is corrected by ion beam removal of material at the location of a defect after the mask is initially formed. In the case of defects due to excess material (opaque defects), the ion beam removes the excess opaque material. In the case of pinholes (clear defects), the substrate (typically glass) is rendered opaque. The ion beam may be used for imaging the defect, typically by detection of secondary electrons or photons emitted where the ion beam impinges on the mask. Optical masks (visible, ultraviolet) and X-ray masks, among others, can be corrected.
Inventors
- 👤 Alfred Wagner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:59
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/88; G03F1/68; G03F1/72; G03F1/74; H; H01; H01J; H01J2237/00; H01J2237/30; H01J2237/317; H01J2237/3174; H01J2237/31745; Y; Y10; Y10S; Y10S430/00; Y10S430/162
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
64 words
A method of correcting an X-ray shadow mask that comprises a pattern of a material that is substantially opaque to X-ray radiation, CHARACTERIZED BY depositing on said pattern a layer of a material having a relatively low sputter yield as compared to that of said pattern, and thereafter directing an ion beam at an opaque defect on said mask, whereby said defect is removed.
Claim 2
Independent Claim
64 words
A method of correcting an X-ray shadow mask that comprises a pattern of a material that is substantially opaque to X-ray radiation, CHARACTERIZED BY depositing on said pattern a layer of a material having a relatively low sputter yield as compared to that of said pattern, and thereafter directing an ion beam at an opaque defect on said mask, whereby said defect is removed.
Claim 3
Dependent Claim
25 words
The method of claim 1 whereby said pattern essentially comprises a material selected from the group consisting of gold, silver, zinc, lead, bismuth and cadmium.
Claim 4
Dependent Claim
26 words
The method of claim 1 whereby said material having a relatively low sputter yield is selected from the group consisting of molybdenum, tantalum, chromium, and aluminum.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein said pattern as formed has a thickness of at least 5000 angstroms.
Claim 6
Dependent Claim
23 words
The method of claim 1 wherein said layer that is deposited on said pattern has a thickness of no more than 1000 angstroms.
Claim 7
Dependent Claim
38 words
The method of claim 1 wherein said ion beam is applied a multiplicity of times to said defect, wherein a depth of material is removed per application that is less than twice the diameter of said ion beam.
References Cited (Backward Citations)
US3748975A
Cited
DE2638474A1
Cited
US4085330A
Cited
JPS55101947A
Cited
JPS55150225A
Cited
US4253029A
Cited
JPS5652751A
Cited
JPS57102019A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-21 | 1989-04-22 | 1989-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-21 | 1993-04-22 | 1993-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-21 | 1997-04-22 | 1997-10-22 | $7700.00 | Window Closed / Lapsed |