US3801910A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Externally accessing mechanical difficult to access circuit nodes using photo-responsive conductors in integrated circuits
Assignee: International Business Machines Corp
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Filing: 1972-07-03
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Granted: 1974-04-02
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Expires: 1992-07-03
Abstract
Abstract A structure for selectively externally accessing mechanically difficult to access circuit nodes in an integrated circuit by the combination of an externally accessible circuit terminal and a plurality of connecting means, each of which connect a particular circuit node which is difficult to access to said terminal. Each of the connecting means includes a photoconductive semiconductor device which is normally electrically nonconductive but which is adapted to electrically conduct when subjected to localized light such as a laser beam. When the particular photoconductive device is rendered conductive, it in turn makes the connecting means associated with it conductive and, thereby, provides a conductive path from the particular circuit node to the externally accessible terminal.
Inventors
- 👤 H Quinn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:25
CPC Classifications
H; H10; H10P; H10P74/00; H10P74/20; H10P74/207; G; G01; G01R; G01R31/00; G01R31/28; G01R31/2851; G01R31/2884; H10F; H10F39/00; H10F39/10; H10F39/107; H10P74/27; H10P74/273; H10P74/277
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
221 words
In a system for testing a semiconductor integrated circuit structure comprising a semiconductor substrate surface from which a plurality of regions of different conductivity types extend into the substrate to provide the active and passive devices of the circuit and a layer of insulative material covering said surface, an integrated circuit further including the combination of a plurality of chip terminals formed on said insulative layer, at least one externally accessible circuit terminal, a plurality of photoconductive semiconductor devices formed at said surface of the substrate, a plurality of first conductive connecting means on said insulative layer, each respectively extending through said insulative layer to connect a respective one of said photoconductive devices to said externally accessible terminal, and a plurality of second conductive connecting means on said insulative layer, each respectively extending through said insulative layer to connect a respective one of said photoconductive devices to a respective one of said chip terminals, said photoconductive devices being normally nonconductive but adapted to conduct when selectively exposed to light to thereby provide a conductive path from the chip terminal to which the exposed device is connected through the exposed device to the externally accessible circuit terminal, means for connecting said externally accessible terminAl to a tester, and means for applying localized light selectively to at least one of said photoconductive devices.
Claim 2
Dependent Claim
221 words
In a system for testing a semiconductor integrated circuit structure comprising a semiconductor substrate surface from which a plurality of regions of different conductivity types extend into the substrate to provide the active and passive devices of the circuit and a layer of insulative material covering said surface, an integrated circuit further including the combination of a plurality of chip terminals formed on said insulative layer, at least one externally accessible circuit terminal, a plurality of photoconductive semiconductor devices formed at said surface of the substrate, a plurality of first conductive connecting means on said insulative layer, each respectively extending through said insulative layer to connect a respective one of said photoconductive devices to said externally accessible terminal, and a plurality of second conductive connecting means on said insulative layer, each respectively extending through said insulative layer to connect a respective one of said photoconductive devices to a respective one of said chip terminals, said photoconductive devices being normally nonconductive but adapted to conduct when selectively exposed to light to thereby provide a conductive path from the chip terminal to which the exposed device is connected through the exposed device to the externally accessible circuit terminal, means for connecting said externally accessible terminAl to a tester, and means for applying localized light selectively to at least one of said photoconductive devices.
Claim 3
Dependent Claim
29 words
The testing system of claim 1 wherein the chip terminals are on a plurality of chips on a wafer and the photoconductive devices are located in the wafer kerf.
Claim 4
Dependent Claim
12 words
The system of claim 1 wherein said localized light is collimated light.
Claim 5
Dependent Claim
13 words
The system of claim 3 wherein said collimated light is a laser beam.
Claim 6
Dependent Claim
12 words
The system of claim 2 wherein said localized light is collimated light.
Claim 7
Dependent Claim
13 words
The system of claim 5 wherein said collimated light is a laser beam.
Claim 8
Dependent Claim
215 words
In the testing of a semiconductor integrated circuit structure comprising a semiconductor substrate surface from which a plurality of regions of different conductivity types extend into the substrate to provide the active and passive devices of the circuit and chip terminals formed on said insulative layer, a method for externally accessing said chip terminals comprising forming in said integrated circuit, a test circuit including at least one externally accessible circuit terminal, a plurality of photoconductive semiconductor devices formed at said surface of the substrate, a plurality of first conductive connecting means on said insulative layer, each respectively extending through said insulative layer to connect a respective one of said photoconductive devices to said externally accessible terminal, and a plurality of second conductive connecting means on said insulative layer, each respectively extending through said insulative layer to connect a respective one of said photoconductive devices to a respective one of said chip terminals, said photoconductive devices being normally nonconductive but adapted to conduct when selectively exposed to light to thereby provide a conductive path from the chip terminal to which the exposed device is connected through the exposed device to the externally accessible circuit terminal, connecting a tester to said externally accessible terminal, and selectively applying localized light to at least one of said photoconductive devices.
Claim 9
Dependent Claim
215 words
In the testing of a semiconductor integrated circuit structure comprising a semiconductor substrate surface from which a plurality of regions of different conductivity types extend into the substrate to provide the active and passive devices of the circuit and chip terminals formed on said insulative layer, a method for externally accessing said chip terminals comprising forming in said integrated circuit, a test circuit including at least one externally accessible circuit terminal, a plurality of photoconductive semiconductor devices formed at said surface of the substrate, a plurality of first conductive connecting means on said insulative layer, each respectively extending through said insulative layer to connect a respective one of said photoconductive devices to said externally accessible terminal, and a plurality of second conductive connecting means on said insulative layer, each respectively extending through said insulative layer to connect a respective one of said photoconductive devices to a respective one of said chip terminals, said photoconductive devices being normally nonconductive but adapted to conduct when selectively exposed to light to thereby provide a conductive path from the chip terminal to which the exposed device is connected through the exposed device to the externally accessible circuit terminal, connecting a tester to said externally accessible terminal, and selectively applying localized light to at least one of said photoconductive devices.
Claim 10
Dependent Claim
29 words
The testing method of claim 7 wherein the chip terminals are on a plurality of chips on a wafer and the photoconductive devices are located in the wafer kerf.
Claim 11
Dependent Claim
12 words
The method of claim 7 wherein said localized light is collimated light.
Claim 12
Dependent Claim
13 words
The method of claim 9 wherein said collimated light is a laser beam.
Claim 13
Dependent Claim
12 words
The method of claim 8 wherein said localized light is collimated light.
Claim 14
Dependent Claim
13 words
The method of claim 11 wherein said collimated light is a laser beam.
Claim 15
Dependent Claim
46 words
The testing system of claim 1 wherein said integrated circuit includes a plurality of said externally accessible circuit terminals and said tester applies signals to at least one of said externally accessible circuit terminals and senses signal from at least one other externally accessible circuit terminal.
Claim 16
Dependent Claim
46 words
The testing method of claim 7 wherein said test circuit includes a plurality of said externally accessible circuit terminals and said tester applies signals to at least one of said externally accessible circuit terminals and senses signal from at least one other externally accessible circuit terminal.
References Cited (Backward Citations)
US3539876A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-01 | 1977-10-01 | 1978-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-01 | 1981-10-01 | 1982-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-01 | 1985-10-01 | 1986-04-02 | $7700.00 | Window Closed / Lapsed |