US4232558A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods for determining bond failure modes using stress wave emission techniques
Assignee: AT&T Inc
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Filing: 1979-04-12
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Granted: 1980-11-11
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Expires: 1999-04-12
Abstract
Abstract As leads that have been thermocompressively bonded to ceramic substrates are pulled to destruction, stress waves are monitored and counted. The total count is compared to empirically developed ranges associated with known failures to determine the failure mode (e.g., lead failure, gold-to-gold failure, ceramic pullout).
Inventors
- 👤 Min-Chung Jon
- 👤 Vito Palazzo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:53
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/14
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
74 words
A method for determining the failure mode of a bonded article during destructive testing, comprising the steps of: monitoring the stress wave emissions emanating from the bonded article during the destructive test; developing a signal that is proportional to the number of excursions of the stress wave emissions above a predetermined threshold; and comparing the developed signal to empirically determined ranges of signals associated with known failure modes to determine the bond failure mode.
Claim 2
Independent Claim
74 words
A method for determining the failure mode of a bonded article during destructive testing, comprising the steps of: monitoring the stress wave emissions emanating from the bonded article during the destructive test; developing a signal that is proportional to the number of excursions of the stress wave emissions above a predetermined threshold; and comparing the developed signal to empirically determined ranges of signals associated with known failure modes to determine the bond failure mode.
Claim 3
Independent Claim
68 words
A method for determining the failure mode of a bonded article during destructive testing, comprising the steps of: monitoring the stress wave emission signals emanating from the bonded article during the destructive test; counting the number of stress wave emission pulses above a predetermined threshold; and comparing the pulse count to ranges of counts associated with specific failure modes to determine the failure mode of the bonded lead.
Claim 4
Independent Claim
68 words
A method for determining the failure mode of a bonded article during destructive testing, comprising the steps of: monitoring the stress wave emission signals emanating from the bonded article during the destructive test; counting the number of stress wave emission pulses above a predetermined threshold; and comparing the pulse count to ranges of counts associated with specific failure modes to determine the failure mode of the bonded lead.
Claim 5
Independent Claim
95 words
A method for determining the failure mode of a lead bonded to a substrate as a destructive pulling force is applied thereto, comprising the steps of: (a) detecting stress wave emission signals generated in the vicinity of the bond during the application of the destructive force; (b) amplifying and monitoring the detected signals; (c) counting the number of excursions of the stress wave emission signals above a predetermined threshold; and (d) comparing the excursion count to ranges of counts that are associated with specific failure modes to determine the failure mode of the bonded lead.
Claim 6
Independent Claim
95 words
A method for determining the failure mode of a lead bonded to a substrate as a destructive pulling force is applied thereto, comprising the steps of: (a) detecting stress wave emission signals generated in the vicinity of the bond during the application of the destructive force; (b) amplifying and monitoring the detected signals; (c) counting the number of excursions of the stress wave emission signals above a predetermined threshold; and (d) comparing the excursion count to ranges of counts that are associated with specific failure modes to determine the failure mode of the bonded lead.
Claim 7
Independent Claim
33 words
The method as set forth in claims 1, 2 or 3 which comprises the further step of: converting the results determined in the comparing step to a visual indication of the failure mode.
Claim 8
Independent Claim
16 words
The method as set forth in claims 1 or 2 wherein the article is thermocompressively bonded.
Claim 9
Independent Claim
16 words
The method as set forth in claims 1 or 2 wherein the article is solder bonded.
Claim 10
Dependent Claim
17 words
The method as set forth in claim 3 wherein the lead is thermocompressively bonded to the substrate.
Claim 11
Dependent Claim
17 words
The method as set forth in claim 3 wherein the lead is solder bonded to the substrate.
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) | 1983-11-11 | 1984-05-12 | 1984-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-11 | 1988-05-12 | 1988-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-11 | 1992-05-12 | 1992-11-11 | $7700.00 | Window Closed / Lapsed |