US3796947A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron beam testing of film integrated circuits
Assignee: AT&T Inc
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Filing: 1973-02-27
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Granted: 1974-03-12
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Expires: 1993-02-27
Abstract
Abstract The application discloses apparatus for testing integrated circuit boards for continuity and isolation of conductive paths on the boards without physical connections to the elements under test. The electrical states of the elements of a board are obtained by observation of the time dependence of secondary electron emission when the elements are the targets of a controllable electron beam which is selectively addressed to the elements under test.
Inventors
- 👤 W Harrod
- 👤 D Hindermann
- 👤 J Sebeson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:53
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/28; G01R31/302; G01R31/305
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
155 words
An arrangement for testing electrical circuits for continuity and isolation of conductive paths comprising: means for holding the circuit to be tested; an electron beam source; means for positioning beams from said source selectively on elements of said circuit; means for controlling said electron beam source to selectively generate electron beams of a selected energy level and selected time duration so as to create a positive charge on a targeted element; a grid interposed between said electron beam source and said circuit, a potential source connected to said grid to define a reference potential; means for measuring the magnitude of secondary electron emission from any selected circuit element of said electrical circuit under test as a function of time relative to the occurrence of an electron beam from said source on said selected element, means for generating signals defining the magnitude and time dependence of said secondary electron emission, and means for interpreting said signals.
Claim 2
Dependent Claim
155 words
An arrangement for testing electrical circuits for continuity and isolation of conductive paths comprising: means for holding the circuit to be tested; an electron beam source; means for positioning beams from said source selectively on elements of said circuit; means for controlling said electron beam source to selectively generate electron beams of a selected energy level and selected time duration so as to create a positive charge on a targeted element; a grid interposed between said electron beam source and said circuit, a potential source connected to said grid to define a reference potential; means for measuring the magnitude of secondary electron emission from any selected circuit element of said electrical circuit under test as a function of time relative to the occurrence of an electron beam from said source on said selected element, means for generating signals defining the magnitude and time dependence of said secondary electron emission, and means for interpreting said signals.
Claim 3
Dependent Claim
69 words
An arrangement in accordance with claim 1 wherein said circuit under test comprises a circuit board comprising a conductive backplate, an insulating layer substantially parallel with and having a first major plane surface in intimate contact with said backplate and a plurality of conductive paths on the second major plane surface of said insulating layer and said arrangement further comprises means for selectively applying control signals to said backplate.
Claim 4
Dependent Claim
64 words
An arrangement in accordance with claim 1 wherein said circuit under test comprises a nonconductive layer having a plane surface, a plurality of conductive paths on said plane surface of said layer, a non-conductive layer overlying said conductive paths, and means for selectively applying potentials to at least certain of said conductive paths; and wherEin said elements comprise portions of said overlying nonconductive layer.
Claim 5
Dependent Claim
146 words
An arrangement in accordance with claim 1 wherein said means for measuring the magnitude of secondary electron emission as a function of time comprises: a secondary electron emission detector for generating output signals corresponding to received secondary electron emission, a sample and hold level comparator circuit comprising: means for storing a first signal corresponding in absolute magnitude to the initial secondary electron emission resulting from the application of said electron beam to a target element, means for storing a second signal corresponding to the absolute magnitude of the secondary emission resulting from the application of said electron beam to a targeted element at a point in time displaced from the occurrence of the emission represented by said first signal, means for comparing said first and said second signals and for generating output signals defining the difference in magnitudes represented by said first and said second samples.
Claim 6
Dependent Claim
73 words
An arrangement in accordance with claim 1 wherein said energy level of said electron beam is selected to be of a value such that the ratio of secondary electron current to electron beam current is substantially greater than unity and said time duration is selected to be sufficiently long to permit the potential of the element targeted with said electron beam to reach an equilibrium potential relative to the potential of said grid.
Claim 7
Independent Claim
96 words
The method of testing electrical circuits comprising the steps: (1) placing a circuit to be tested in a defined relation with a controllable electron beam source, a reference potential grid, and a secondary emission electron detector; (2) directing an electron beam of a selected energy level such that the secondary electron emission from an element of the circuit targeted by the beam substantially exceeds the electron beam current; (3) measuring the secondary electron emission from the targeted elements and generating discrete signals defining the time dependence of that secondary electron emission; and (4) interpreting said signals.
Claim 8
Independent Claim
96 words
The method of testing electrical circuits comprising the steps: (1) placing a circuit to be tested in a defined relation with a controllable electron beam source, a reference potential grid, and a secondary emission electron detector; (2) directing an electron beam of a selected energy level such that the secondary electron emission from an element of the circuit targeted by the beam substantially exceeds the electron beam current; (3) measuring the secondary electron emission from the targeted elements and generating discrete signals defining the time dependence of that secondary electron emission; and (4) interpreting said signals.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |