US3703637A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron beam inspection
Assignee: AT&T Inc
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Filing: 1970-11-23
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Granted: 1972-11-21
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Expires: 1990-11-23
Abstract
Abstract Differences between the secondary electron emission characteristics of two phases of the same material in response to bombardment by an electron beam are sensed to enable impurities, comprising one of the material''s phases, in a sample, comprising the material''s phase, to be detected. The electron beam is a low energy beam. Relative motion between the sample and the beam may be effected by sweeping the beam, by moving the sample, or by a combination of the two motions.
Inventors
- 👤 Allan Edward Dugan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:04
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/252; H01J37/256
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
168 words
A method of detecting, in a sample of a first phase of a material, the presence of a second, different phase of the material, said first and second phases having the same atomic number Z, which comprises the steps of: impinging said sample with a low energy electron beam, the electrons in said beam having energies falling within the approximate range 0.2-2.0 keV for effecting the emission from said sample of secondary electrons, substantially all of which have energies within the range 0-15 eV, and back-scattered electrons in approximately equal numbers from both phases of said material; capturing said secondary electrons to the substantial exclusion of said back-scattered electrons to thereby derive a current proportional to the number of said emitted secondary electrons; and relatively moving said beam and the sample and simultaneously detecting, in synchronization with said relative motion, variations in said derived current for indicating changes in the number of said emitted secondary electrons to detect the presence of the second material phase in the sample.
Claim 2
Independent Claim
168 words
A method of detecting, in a sample of a first phase of a material, the presence of a second, different phase of the material, said first and second phases having the same atomic number Z, which comprises the steps of: impinging said sample with a low energy electron beam, the electrons in said beam having energies falling within the approximate range 0.2-2.0 keV for effecting the emission from said sample of secondary electrons, substantially all of which have energies within the range 0-15 eV, and back-scattered electrons in approximately equal numbers from both phases of said material; capturing said secondary electrons to the substantial exclusion of said back-scattered electrons to thereby derive a current proportional to the number of said emitted secondary electrons; and relatively moving said beam and the sample and simultaneously detecting, in synchronization with said relative motion, variations in said derived current for indicating changes in the number of said emitted secondary electrons to detect the presence of the second material phase in the sample.
Claim 3
Independent Claim
168 words
A method of detecting, in a sample of a first phase of a material, the presence of a second, different phase of the material, said first and second phases having the same atomic number Z, which comprises the steps of: impinging said sample with a low energy electron beam, the electrons in said beam having energies falling within the approximate range 0.2-2.0 keV for effecting the emission from said sample of secondary electrons, substantially all of which have energies within the range 0-15 eV, and back-scattered electrons in approximately equal numbers from both phases of said material; capturing said secondary electrons to the substantial exclusion of said back-scattered electrons to thereby derive a current proportional to the number of said emitted secondary electrons; and relatively moving said beam and the sample and simultaneously detecting, in synchronization with said relative motion, variations in said derived current for indicating changes in the number of said emitted secondary electrons to detect the presence of the second material phase in the sample.
Claim 4
Independent Claim
168 words
A method of detecting, in a sample of a first phase of a material, the presence of a second, different phase of the material, said first and second phases having the same atomic number Z, which comprises the steps of: impinging said sample with a low energy electron beam, the electrons in said beam having energies falling within the approximate range 0.2-2.0 keV for effecting the emission from said sample of secondary electrons, substantially all of which have energies within the range 0-15 eV, and back-scattered electrons in approximately equal numbers from both phases of said material; capturing said secondary electrons to the substantial exclusion of said back-scattered electrons to thereby derive a current proportional to the number of said emitted secondary electrons; and relatively moving said beam and the sample and simultaneously detecting, in synchronization with said relative motion, variations in said derived current for indicating changes in the number of said emitted secondary electrons to detect the presence of the second material phase in the sample.
Claim 5
Dependent Claim
24 words
The method of claim 1 wherein said material is tantalum and said first and second phases are respectively the Alpha and Beta phases thereof.
Claim 6
Dependent Claim
24 words
The method of claim 1 wherein said material is tantalum and said first and second phases are respectively the Beta and Alpha phases thereof.
References Cited (Backward Citations)
US3479506A
Cited
US3473023A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-21 | 1976-05-22 | 1976-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-21 | 1980-05-22 | 1980-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-21 | 1984-05-22 | 1984-11-21 | $7700.00 | Window Closed / Lapsed |