Patent US3558885A successfully refreshed from Google Patents.
US3558885A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scanning microscope with feedback means to maintain a constant target current
Assignee: International Standard Electric Corp
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Filing: 1968-10-08
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Granted: 1971-01-26
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Expires: 1988-10-08
Abstract
Abstract The invention includes a scanning mirror microscope having a feedback control loop between target and cathode to stabilize the target current. It is then possible to obtain a quantitative plot of the target voltage by scanning an electron beam over the target surface. The invention also includes a scanning electron microscope having a feedback control loop between the target and the output of a velocity analyzer of secondary electrons emitted from the target to obtain the same quantitative plot. In either case, examination tests on semiconductor integrated circuits are made possible.
Inventors
- 👤 John P W Flemming
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:01
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/26; H01J37/29; H01J37/292; H01J37/252; H01J37/256; H01J37/28
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
75 words
An electron bombardment examination device comprising; a scanning mirror microscope including means to scan an electron beam across a target and a cathode; and a feedback control loop adapted to be actuated by the output current from said target, said loop being connected to control the potential difference between said cathode and said target in a manner to reduce fluctuations in said output current as said electron beam scans over the surface of said target.
Claim 2
Dependent Claim
75 words
An electron bombardment examination device comprising; a scanning mirror microscope including means to scan an electron beam across a target and a cathode; and a feedback control loop adapted to be actuated by the output current from said target, said loop being connected to control the potential difference between said cathode and said target in a manner to reduce fluctuations in said output current as said electron beam scans over the surface of said target.
Claim 3
Dependent Claim
33 words
The invention as defined in claim 1, wherein said feedback control loop includes an amplifier responsive to said output current for controlling the potential difference between said target and said cathode inversely therewith.
Claim 4
Dependent Claim
79 words
An electron bombardment examination device comprising: a scanning electron microscope including means to scan an electron beam across a target; a velocitY analyzer; and a feedback control loop adapted to be actuated by the output from said velocity analyzer to control the potential of said target according to the electron energy level accepted by said velocity analyzer and in such a manner as to reduce fluctuations in said output as the electron beam scans the surface of the target.
Claim 5
Dependent Claim
79 words
An electron bombardment examination device comprising: a scanning electron microscope including means to scan an electron beam across a target; a velocitY analyzer; and a feedback control loop adapted to be actuated by the output from said velocity analyzer to control the potential of said target according to the electron energy level accepted by said velocity analyzer and in such a manner as to reduce fluctuations in said output as the electron beam scans the surface of the target.
Claim 6
Dependent Claim
44 words
The invention as defined in claim 3, wherein said feedback control loop includes an amplifier responsive to the output of said velocity analyzer for controlling the potential of said target inversely therewith, said velocity analyzer being positioned to intercept secondary electrons from said target.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-25 | 1974-07-27 | 1975-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-25 | 1978-07-27 | 1979-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-25 | 1982-07-27 | 1983-01-26 | $7700.00 | Window Closed / Lapsed |