US4293374A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High aspect ratio, high resolution mask fabrication
Assignee: International Business Machines Corp
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Filing: 1980-03-10
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Granted: 1981-10-06
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Expires: 2000-03-10
Abstract
Abstract A high aspect ratio collimating mask for use in ion beam epitaxy or ion implantation doping is formed through the use of damage-trail-forming materials which are irradiated through a mask and then etched. The high aspect ratio is obtained in part by the sequential formation of a plurality of spaced mask plates. The mask is useful in producing large scale integrated circuits by ion implantation during epitaxial growth of a crystal wafer.
Inventors
- 👤 Praveen Chaudhari
- 👤 Ned J. Chou
- 👤 Ralph Feder
- 👤 Alan B. Fowler
- 👤 James A. VanVechten
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:00
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/20; H; H10; H10P; H10P30/00; H10P30/20; H10P30/22; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/944
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
137 words
The process of making a high aspect ratio collimating mask comprising the step of: forming on a first thin plate of damage-trail-forming material, a preliminary mask of particle-arresting material configured to leave unmasked regions where openings are to be formed, irradiating said first plate through said preliminary mask with particles having sufficient energy to pass through said first plate with negligible deflection and form damage trails therethrough, etching said first plate to enlarge said damage trails, mounting a second thin plate of damage-trail-forming material spaced from and superimposed with said first plate, irradiating said second plate through said preliminary mask and the enlarged damage trails in said first plate, with particles energized sufficiently to pass through said second plate with negligible deflection and form damage trails therethrough, and etching said second plate to enlarge said damage trails.
Claim 2
Dependent Claim
137 words
The process of making a high aspect ratio collimating mask comprising the step of: forming on a first thin plate of damage-trail-forming material, a preliminary mask of particle-arresting material configured to leave unmasked regions where openings are to be formed, irradiating said first plate through said preliminary mask with particles having sufficient energy to pass through said first plate with negligible deflection and form damage trails therethrough, etching said first plate to enlarge said damage trails, mounting a second thin plate of damage-trail-forming material spaced from and superimposed with said first plate, irradiating said second plate through said preliminary mask and the enlarged damage trails in said first plate, with particles energized sufficiently to pass through said second plate with negligible deflection and form damage trails therethrough, and etching said second plate to enlarge said damage trails.
Claim 3
Dependent Claim
29 words
The process as defined in claim 1 wherein said damage-trail-forming material is selected from the group consisting of Al 2 O 3 , SiO 2 , mica and garnet.
Claim 4
Dependent Claim
13 words
The process, as defined in claim 1, wherein said particle-arresting material comprises gold.
Claim 5
Dependent Claim
39 words
The process, as defined in claim 1, wherein said damage-trail-forming material is sapphire with the plates thereof having a thickness of about 10 microns, and wherein the energy of said irradiation is in the order of 1 MeV protons.
Claim 6
Dependent Claim
24 words
The process, as defined in claim 3, wherein said particle-arresting material comprises gold and said preliminary mask has a thickness of about 10 microns.
Claim 7
Dependent Claim
35 words
The process, as defined in claim 1, wherein said plates each have a thickness of about 10 microns, the openings therethrough are etched to about 100 nanometers, and the spacing therebetween is about 1 centimeter.
References Cited (Backward Citations)
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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) | 1984-10-05 | 1985-04-06 | 1985-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-05 | 1989-04-06 | 1989-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-05 | 1993-04-06 | 1993-10-06 | $7700.00 | Window Closed / Lapsed |