US4554455A
Expired / Lapsed
US
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Potential analyzer
Assignee: Hitachi Ltd
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Filing: 1983-07-28
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Granted: 1985-11-19
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Expires: 2003-07-28
Abstract
Abstract A potential analyzer, suitable for use in measuring the potential of a specimen such as LSI by means of an electron beam probe, comprises a detector for detecting secondary electrons emitted from the specimen irradiated with a primary electron beam, a grid electrode disposed between the detector and the specimen, a power source for applying to the grid electrode a voltage which determines the lower limit of the energy of the secondary electrons detected by the detector, the voltage being changed within a predetermined range, and a filter circuit for averaging the output of the detector produced during a period of time in which the voltage applied to the grid electrode is changed.
Inventors
- 👤 Hideo Todokoro
- 👤 Satoru Fukuhara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:37
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/28; G01R31/302; G01R31/305
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
115 words
A potential analyzer comprising: detector means for detecting secondary electrons emitted from a specimen irradiated with a primary electron beam; grid means disposed between said specimen and said detector means, said grid means including at least a grid electrode for determining a lower limit of the energy of the secondary electrons to be detected by said detector means; voltage source means for applying a voltage to said grid electrode which voltage varies within a predetermined range during the measurement of the potential of said specimen; and circuit means for producing an average value of the output of said detector means during a period of time in which the voltage applied to said grid electrode varies.
Claim 2
Dependent Claim
115 words
A potential analyzer comprising: detector means for detecting secondary electrons emitted from a specimen irradiated with a primary electron beam; grid means disposed between said specimen and said detector means, said grid means including at least a grid electrode for determining a lower limit of the energy of the secondary electrons to be detected by said detector means; voltage source means for applying a voltage to said grid electrode which voltage varies within a predetermined range during the measurement of the potential of said specimen; and circuit means for producing an average value of the output of said detector means during a period of time in which the voltage applied to said grid electrode varies.
Claim 3
Dependent Claim
28 words
A potential analyzer according to claim 1, wherein said circuit means includes a filter circuit connected at the output of said detector means for producing said average value.
Claim 4
Dependent Claim
31 words
A potential analyzer according to claim 2, wherein said filter circuit includes a filter having a cut-off frequency for blocking frequency components included in the voltage applied to said grid electrode.
Claim 5
Dependent Claim
20 words
A potential analyzer according to claim 2, wherein the voltage applied to said grid electrode includes an alternating current component.
Claim 6
Dependent Claim
23 words
A potential analyzer according to claim 3, wherein the voltage applied to said grid electrode includes a high-frequency triangular or saw-tooth wave voltage.
Claim 7
Dependent Claim
54 words
A potential analyzer according to claim 1, wherein said grid means includes at least one first grid electrode for accelerating the second electrons emitted from said specimen, and the earlier-mentioned grid electrode as a second grid electrode for determining the lower limit of the secondary electron energy to be detected by said detector means.
Claim 8
Dependent Claim
33 words
A potential analyzer according to claim 6, wherein said circuit means includes a filter circuit having a cut-off frequency for blocking frequency components included in the voltage applied to said second grid electrode.
Claim 9
Dependent Claim
23 words
A potential analyzer according to claim 7, wherein the voltage applied to said second grid electrode includes a triangular or saw-tooth wave voltage.
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) | 1988-11-18 | 1989-05-20 | 1989-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-18 | 1993-05-20 | 1993-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-18 | 1997-05-20 | 1997-11-19 | $7700.00 | Window Closed / Lapsed |