US5019771A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Contact sensing for integrated circuit testing
Assignee: Martek Inc
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Filing: 1990-05-21
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Granted: 1991-05-28
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Expires: 2010-05-21
Abstract
Abstract A technique for detecting whether electrical contact between a probe tip and a device under test ("DUT") has been established. A contact sensing circuit has a ground that is isolated from the ground of the DUT (and remaining portions of the test equipment) during contact sensing. The contact sensing circuit has elements that operate to apply a characteristic signal to one of the DUT terminals, such as its ground terminal. This causes virtually all the DUT circuit traces to track the applied signal (relative to the contact sensing ground). The contact sensing circuit further includes elements, coupled to the probe, that operate to detect the presence of the characteristic signal (relative to the contact sensing ground) on the probe. Once electrical contact has been established, the characteristic signal output is disconnected from the DUT, the test equipment ground is connected to the contact sensing circuit ground, and the probe output is coupled to the relevant portions of the test equipment circuitry.
Inventors
- 👤 Tsen-Shau Yang
- 👤 Ger-Chih Chou
- 👤 Fu-Chieh Hsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:25
CPC Classifications
G; G01; G01R; G01R1/00; G01R1/02; G01R1/06; G01R1/067; G01R1/06794
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
268 words
Circuitry for use with test apparatus having a test apparatus input terminal and an associated probe having a probe tip and a probe output, for sensing the status of electrical contact between the probe tip and a device under test ("DUT") in the test apparatus, comprising: generator means, having a generator reference terminal and a generator output terminal, for providing a first signal on said generator output terminal relative to said generator reference terminal, said first signal having a defined characteristics; and detector means, having a detector input terminal, a detector output terminal, and a detector reference terminal, for providing a second signal on said detector output terminal relative to said detector reference terminal, said second signal representing the amount of signal having the defined characteristic relative to said detector reference terminal appearing at said detector input terminal; said generator and detector reference terminals being electrically connected to each other; and means for selectively establishing a contact sensing mode and a measurement mode, said contact sensing mode being characterized in that said generator and detector reference terminals are at least partially isolated from the DUT, said generator output terminal is coupled to the DUT, and the probe output is disconnected from the test apparatus input terminal and coupled to said detector input terminal, whereupon said second signal provides an indication of the degree of electrical contact between the probe tip and the DUT, said measurement mode being characterized in that said generator output terminal is disconnected from the DUT and the probe output is disconnected from the detector input terminal and coupled to the test apparatus input terminal.
Claim 2
Dependent Claim
268 words
Circuitry for use with test apparatus having a test apparatus input terminal and an associated probe having a probe tip and a probe output, for sensing the status of electrical contact between the probe tip and a device under test ("DUT") in the test apparatus, comprising: generator means, having a generator reference terminal and a generator output terminal, for providing a first signal on said generator output terminal relative to said generator reference terminal, said first signal having a defined characteristics; and detector means, having a detector input terminal, a detector output terminal, and a detector reference terminal, for providing a second signal on said detector output terminal relative to said detector reference terminal, said second signal representing the amount of signal having the defined characteristic relative to said detector reference terminal appearing at said detector input terminal; said generator and detector reference terminals being electrically connected to each other; and means for selectively establishing a contact sensing mode and a measurement mode, said contact sensing mode being characterized in that said generator and detector reference terminals are at least partially isolated from the DUT, said generator output terminal is coupled to the DUT, and the probe output is disconnected from the test apparatus input terminal and coupled to said detector input terminal, whereupon said second signal provides an indication of the degree of electrical contact between the probe tip and the DUT, said measurement mode being characterized in that said generator output terminal is disconnected from the DUT and the probe output is disconnected from the detector input terminal and coupled to the test apparatus input terminal.
Claim 3
Dependent Claim
18 words
The circuit of claim 1 wherein said generator means is a sine wave oscillator having a characteristic frequency.
Claim 4
Dependent Claim
22 words
The circuit of claim 2 wherein said detector means comprises a band pass filter operable to pass signals at said characteristic frequency.
Claim 5
Dependent Claim
20 words
The circuit of claim 3 wherein said detector means further comprises a peak detector coupled to said band pass filter.
Claim 6
Dependent Claim
27 words
The circuit of claim 1, and further comprising visual indicator means, responsive to said second signal, for providing a visual indication of a desired degree of contact.
Claim 7
Dependent Claim
13 words
The circuit of claim 5 wherein said visual indicator means comprises an LED.
Claim 8
Dependent Claim
36 words
The circuit of claim 1, and further comprising optical coupling means, responsive to said second signal, for generating a signal representative of said second signal relative to a reference that is not isolated from the DUT.
Claim 9
Dependent Claim
236 words
Circuitry for sensing the status of electrical contact between a plurality of probes and a device under test ("DUT"), comprising: generator means, having a generator reference terminal and a generator output terminal, for providing a first signal on said generator output terminal relative to said generator reference terminal, said first signal having a defined characteristic; and a corresponding plurality of detector means, each associated with a respective one of the probes, each having a detector input terminal, a detector output terminal, and a detector reference terminal, for providing a second signal on said detector output terminal relative to said detector reference terminal, said second signal representing the amount of signal having the defined characteristic relative to said detector reference terminal appearing at said detector input terminal; said generator and detector reference terminals being electrically connected to each other; and means for selectively establishing a contact sensing mode and a measurement mode, said contact sensing mode being characterized in that said generator and detector reference terminals are at least partially isolated from the DUT, said generator output terminal is coupled to the DUT, and the probes are coupled to said detector input terminals, whereupon said second signals provide indications of the degree of electrical contact between the probe tips and the DUT, said measurement mode being characterized in that said generator output terminal is disconnected from the DUT and said probe is connected to the test apparatus.
Claim 10
Dependent Claim
236 words
Circuitry for sensing the status of electrical contact between a plurality of probes and a device under test ("DUT"), comprising: generator means, having a generator reference terminal and a generator output terminal, for providing a first signal on said generator output terminal relative to said generator reference terminal, said first signal having a defined characteristic; and a corresponding plurality of detector means, each associated with a respective one of the probes, each having a detector input terminal, a detector output terminal, and a detector reference terminal, for providing a second signal on said detector output terminal relative to said detector reference terminal, said second signal representing the amount of signal having the defined characteristic relative to said detector reference terminal appearing at said detector input terminal; said generator and detector reference terminals being electrically connected to each other; and means for selectively establishing a contact sensing mode and a measurement mode, said contact sensing mode being characterized in that said generator and detector reference terminals are at least partially isolated from the DUT, said generator output terminal is coupled to the DUT, and the probes are coupled to said detector input terminals, whereupon said second signals provide indications of the degree of electrical contact between the probe tips and the DUT, said measurement mode being characterized in that said generator output terminal is disconnected from the DUT and said probe is connected to the test apparatus.
Claim 11
Dependent Claim
32 words
The circuitry of claim 8, and further comprising: a multiplexer having multiplexer inputs coupled to said detector output terminals and a multiplexer output that provides a selected one of said second signals.
Claim 12
Independent Claim
80 words
A method of sensing the status of electrical contact between a probe and a device under test ("DUT"), comprising the steps of: applying a signal having a defined characteristic to a node on the DUT, the signal being referenced to a level at least partially isolated from the DUT; sensing signals on the probe relative to the level at least partially isolated from the DUT; and determining the degree to which the signals on the probe having the defined characteristic.
Claim 13
Independent Claim
80 words
A method of sensing the status of electrical contact between a probe and a device under test ("DUT"), comprising the steps of: applying a signal having a defined characteristic to a node on the DUT, the signal being referenced to a level at least partially isolated from the DUT; sensing signals on the probe relative to the level at least partially isolated from the DUT; and determining the degree to which the signals on the probe having the defined characteristic.
Claim 14
Dependent Claim
32 words
The method of claim 10 wherein the DUT is a die on a wafer which is held to a chuck, and wherein said applying step comprises applying the signal to the chuck.
Claim 15
Dependent Claim
16 words
The method of claim 10 wherein said applying step comprises applying the signal to DUT ground.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-05-27 | 1994-11-26 | 1995-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-05-27 | 1998-11-26 | 1999-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-05-27 | 2002-11-26 | 2003-05-28 | $7700.00 | Window Closed / Lapsed |