US3828606A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for determining thermal fatigue of electronic components
Assignee: Boeing Co
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Filing: 1972-12-06
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Granted: 1974-08-13
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Expires: 1992-12-06
Abstract
Abstract A method for determining thermal fatigue of electronic circuits and parts therefor includes the use of a thin-film thermal strain gage made from metals including metal alloys which are deposited on a preselected substrate by vacuum evaporation, sputtering, coevaporation or similar techniques. The substrate material is selected in relation to the resistor gage material in such a manner as to create a predetermined mismatch of thermal expansion coefficient. The resistivity of the gage is responsive to a spectrum of temperature changes and reveals the progress toward ultimate failure of the circuit. The gage may take the form of a narrow strip-like assembly which is arranged immediately adjacent to an electronic device, component or other parts subject to failure due to thermal fatigue.
Inventors
- 👤 A Wolter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:19
CPC Classifications
G; G01; G01N; G01N25/00; G01N25/72
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
130 words
A method of determining the fatigue experience of a thermal sensitive electronic circuit and the like comprising the steps of: selecting a thermal fatigue material for a thin-film gage, said material having an irreversible strain sensitivity selected to correspond to the spectrum of thermal damage incurred by said circuit and part therefor, utilizing a substance material having a selected thermal expansion coefficient different from the thermal expansion coefficient of said thermal fatigue material, and forming a thermal fatigue thin-film gage by film deposits of said thermal fatigue material upon said substrate material to undergo resistivity changes in response to essentially the same thermal excursions as experienced by said thermal sensitive electronic circuit, determining the resistivity change of said thermal fatigue gage to reveal the progress toward failure of said circuit.
Claim 2
Independent Claim
130 words
A method of determining the fatigue experience of a thermal sensitive electronic circuit and the like comprising the steps of: selecting a thermal fatigue material for a thin-film gage, said material having an irreversible strain sensitivity selected to correspond to the spectrum of thermal damage incurred by said circuit and part therefor, utilizing a substance material having a selected thermal expansion coefficient different from the thermal expansion coefficient of said thermal fatigue material, and forming a thermal fatigue thin-film gage by film deposits of said thermal fatigue material upon said substrate material to undergo resistivity changes in response to essentially the same thermal excursions as experienced by said thermal sensitive electronic circuit, determining the resistivity change of said thermal fatigue gage to reveal the progress toward failure of said circuit.
Claim 3
Dependent Claim
19 words
The method of claim 1 including the step of: delineating the geometry of said thin-film gage by photolithographic means.
Claim 4
Dependent Claim
28 words
The method of claim 1 Including the step of: selecting an elevated temperature and superatmospheric pressure for depositing a film of said gage material upon said substrate material.
Claim 5
Dependent Claim
27 words
The method of claim 3 including the step of: heat-treating the thin-film gage material after depositing upon said substrate material to maintain thermal stability of said gage.
Claim 6
Dependent Claim
21 words
The method of claim 4 wherein said forming a thermal fatigue thin-film gage includes depositing a gate film by metal evaporation.
Claim 7
Dependent Claim
21 words
The method of claim 4 wherein said forming a thermal fatigue thin-film gage include depositing a gage film by metal sputtering.
Claim 8
Dependent Claim
21 words
The method of claim 4 wherein said forming a thermal fatigue thin-film gage includes depositing a gage film by metal co-evaporation.
Claim 9
Dependent Claim
29 words
The method according to claim 1 wherein the difference between the thermal expansion coefficients of the gage material and substrate material produces a thermal threshold sensitivity less than 150*C.
Claim 10
Dependent Claim
18 words
The method according to claim 1 wherein said thermal fatigue material is further defined as a metal alloy.
Claim 11
Dependent Claim
18 words
The method according to claim 9 wherein said metal alloy is further defined as a three element alloy.
Claim 12
Dependent Claim
25 words
The method according to claim 1 including the step of arranging said thermal fatigue gage at a point of potential failure in said electronic circuit.
Claim 13
Dependent Claim
33 words
The method according to claim 11 wherein said arranging of the thermal fatigue gage at a point of potential failure further includes incorporating said fatigue gage as an integral part of electronic circuits.
Claim 14
Dependent Claim
22 words
The method of claim 11 where said resistivity change is determined by a resistance measurement taken at spaced location on said gage.
Claim 15
Dependent Claim
25 words
The method of claim 13 including the step of: using electrical conductors at opposed ends of said thermal fatigue gage for determining said resistivity change.
Claim 16
Dependent Claim
29 words
The method of claim 14 wherein said electronic circuit is further defined to include a microelectronic circuit and said resistivity change is measured at points remote to said circuit.
References Cited (Backward Citations)
US3186228A
Cited
US3272003A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-12 | 1978-02-11 | 1978-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-12 | 1982-02-11 | 1982-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-12 | 1986-02-11 | 1986-08-13 | $7700.00 | Window Closed / Lapsed |