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US3961102A
Expired / Lapsed
US
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Scanning electron microscope fabrication of optical gratings
Assignee: Cornell Research Foundation Inc
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Filing: 1974-09-13
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Granted: 1976-06-01
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Expires: 1994-09-13
Abstract
Abstract A method of making optical gratings by the use of a Scanning Electron Microscope wherein (1) a substrate having a thin film of electron resist thereon is exposed in adjacent areas by an electron dosage and the amount of such dosage and the depth of the thin film are selected such that energy deposition in regions between adjacent exposed areas in said electron resist is below the threshold sensitivity of said resist for development, (2) the development time of the resist is made an inverse function of the electron dosage, and/or (3) the period of the grating is controlled by use of a standard scanning format.
Inventors
- 👤 Joseph M. Ballantyne
- 👤 Chung L. Tang
- 👤 Lawrence Bryce Rhodes
- 👤 John J. Turner
- 👤 Ji Liang Yang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:10
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/30; H01J37/305; H01J37/3053; H01J37/3056; G; G02; G02B; G02B5/00; G02B5/18; G02B5/1847; G02B5/1857; G03; G03F; G03F7/00; G03F7/0005; G03F7/001
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
169 words
In the method of making optical gratings which includes the steps of (1) providing a structure having a substrate with a film of electron resist material thereon, (2) exposing adjacent areas by electron dosage, and (3) developing the electron resist; the improvement which comprises: a. determining the electron scattering characteristics of said substrate and said film as an inverse function of their densities, and b. selecting values for resist thickness and electron dosage such that, for a given grating period, the total energy deposited by the electron beam (including scattered as well as unscattered electrons) will cause the resist in the areas of the grating lines and the resist in the areas between grating lines to react differently to a substantial degree during development, the electron beam penetration being such that when the depth of the groove produced when the resist is exposed and developed is at its maximum dimension, the width of the groove at its maximum dimension is less than one-half of the period of the grating.
Claim 2
Dependent Claim
169 words
In the method of making optical gratings which includes the steps of (1) providing a structure having a substrate with a film of electron resist material thereon, (2) exposing adjacent areas by electron dosage, and (3) developing the electron resist; the improvement which comprises: a. determining the electron scattering characteristics of said substrate and said film as an inverse function of their densities, and b. selecting values for resist thickness and electron dosage such that, for a given grating period, the total energy deposited by the electron beam (including scattered as well as unscattered electrons) will cause the resist in the areas of the grating lines and the resist in the areas between grating lines to react differently to a substantial degree during development, the electron beam penetration being such that when the depth of the groove produced when the resist is exposed and developed is at its maximum dimension, the width of the groove at its maximum dimension is less than one-half of the period of the grating.
Claim 3
Dependent Claim
108 words
In the method of making optical gratings which includes the steps of (1) providing a structure having a substrate with a film of electron resist material thereon, (2) exposing adjacent areas by electron dosage, and (3) developing the electron resist; the improvement which comprises: selecting a time period for said developing of the electron resist as an inverse function of the electron dosage, the electron beam penetration being such that when the depth of the groove produced when the resist is exposed and developed is at its maximum dimension, the width of the groove at its maximum dimension is less than one-half of the period of the grating.
Claim 4
Dependent Claim
108 words
In the method of making optical gratings which includes the steps of (1) providing a structure having a substrate with a film of electron resist material thereon, (2) exposing adjacent areas by electron dosage, and (3) developing the electron resist; the improvement which comprises: selecting a time period for said developing of the electron resist as an inverse function of the electron dosage, the electron beam penetration being such that when the depth of the groove produced when the resist is exposed and developed is at its maximum dimension, the width of the groove at its maximum dimension is less than one-half of the period of the grating.
Claim 5
Dependent Claim
189 words
In the method of making optical gratings which includes the steps of (1) providing a structure having a substrate with a film of electron resist material thereon, (2) exposing adjacent areas by electron dosage, and (3) developing the electron resist; the improvement which comprises: a. determining the electron scattering characteristics of said substrate and said film as an inverse function of its density, b. selecting values for resist thickness and electron dosage such that, for a given grating period, the total energy deposited by the electron beam (including scattered as well as unscattered electrons) will cause the resist in the areas of the grating lines and the resist in the areas between grating lines to react differently to a substantial degree during development, and c. selecting a time period for said developing of the electron resist as an inverse function of the electron dosage, the electron beam penetration being such that when the depth of the groove produced when the resist is exposed and developed is at its maximum dimension, the width of the groove at its maximum dimension is less than one-half of the period of the grating.
Claim 6
Dependent Claim
189 words
In the method of making optical gratings which includes the steps of (1) providing a structure having a substrate with a film of electron resist material thereon, (2) exposing adjacent areas by electron dosage, and (3) developing the electron resist; the improvement which comprises: a. determining the electron scattering characteristics of said substrate and said film as an inverse function of its density, b. selecting values for resist thickness and electron dosage such that, for a given grating period, the total energy deposited by the electron beam (including scattered as well as unscattered electrons) will cause the resist in the areas of the grating lines and the resist in the areas between grating lines to react differently to a substantial degree during development, and c. selecting a time period for said developing of the electron resist as an inverse function of the electron dosage, the electron beam penetration being such that when the depth of the groove produced when the resist is exposed and developed is at its maximum dimension, the width of the groove at its maximum dimension is less than one-half of the period of the grating.
Claim 7
Independent Claim
125 words
A method of operating a scanning electron microscope which includes the steps of (1) adjusting the scan pattern by observing the scan of a standard of known absolute dimensions such that known positions of the electron beam are made to correspond to some absolute dimensions of the standard and (2) causing the scan pattern so adjusted to strike the target area such that the known positions of the electron beam correspond to the same absolute dimensions as on the standard, the electron beam penetration being such that when the depth of the groove produced when the resist is exposed and developed is at its maximum dimension, the width of the groove at its maximum dimension is less than one-half of the period of the grating.
Claim 8
Independent Claim
125 words
A method of operating a scanning electron microscope which includes the steps of (1) adjusting the scan pattern by observing the scan of a standard of known absolute dimensions such that known positions of the electron beam are made to correspond to some absolute dimensions of the standard and (2) causing the scan pattern so adjusted to strike the target area such that the known positions of the electron beam correspond to the same absolute dimensions as on the standard, the electron beam penetration being such that when the depth of the groove produced when the resist is exposed and developed is at its maximum dimension, the width of the groove at its maximum dimension is less than one-half of the period of the grating.
Claim 9
Independent Claim
103 words
A method of making optical gratings by the use of a scanning electron microscope which includes the steps of (1) adjusting the scan pattern by observing the scan on a known dimension standard, and (2) causing the adjusted scan pattern to expose the electron resist of said optical grating to thereby produce a grating having a predetermined period, the electron beam penetration being such that when the depth of the groove produced when the resist is exposed and developed is at its maximum dimension the width of the groove at its maximum dimension is less than one-half of the period of the grating.
Claim 10
Independent Claim
103 words
A method of making optical gratings by the use of a scanning electron microscope which includes the steps of (1) adjusting the scan pattern by observing the scan on a known dimension standard, and (2) causing the adjusted scan pattern to expose the electron resist of said optical grating to thereby produce a grating having a predetermined period, the electron beam penetration being such that when the depth of the groove produced when the resist is exposed and developed is at its maximum dimension the width of the groove at its maximum dimension is less than one-half of the period of the grating.
Claim 11
Dependent Claim
39 words
The method of claim 1 wherein the electron resist is of the negative type whereby the areas of the grating lines will receive sufficient energy for cross-linking and areas between the grating lines will receive insufficient energy for cross-linking.
Claim 12
Dependent Claim
39 words
The method of claim 1 wherein the electron resist is of the positive type whereby the areas of the grating lines will receive sufficient energy for development and areas between the grating lines will receive insufficient energy for development.
Claim 13
Dependent Claim
48 words
The method of claim 7 wherein the period of said grating is selected within the range of 90-2500 nm, the thickness of said thin film of electron resist is less than 3500 A, and the dosage is selected within the range of (2-75)×10 - 10 C/cm 2 .
Claim 14
Dependent Claim
47 words
The method of claim 3 wherein the period of said grating is selected within the range of 300-375 nm, the dosage is selected within the range of (6-16)×10 - 10 C/cm 2 , and the time for developing said resist is selected within the range 8-40 seconds.
Claim 15
Dependent Claim
12 words
The method of claim 1 wherein the grating lines are non-uniformly spaced.
Claim 16
Dependent Claim
12 words
The method of claim 1 wherein the grating lines are non-straight lines.
Claim 17
Dependent Claim
9 words
A product produced by the method of claim 1.
Claim 18
Dependent Claim
9 words
A product produced by the method of claim 2.
Claim 19
Dependent Claim
9 words
A product produced by the method of claim 3.
Claim 20
Dependent Claim
9 words
A product produced by the method of claim 5.
References Cited (Backward Citations)
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US3681103A
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US3679497A
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US3775592A
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US3703402A
Cited
US3843875A
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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) | 1979-06-01 | 1979-12-01 | 1980-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-01 | 1983-12-01 | 1984-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-01 | 1987-12-01 | 1988-06-01 | $7700.00 | Window Closed / Lapsed |