US4455741A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fabrication of solid state electronic devices using fluorescent imaging of surface temperature profiles
Assignee: Nokia Bell Labs
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Filing: 1982-10-15
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Granted: 1984-06-26
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Expires: 2002-10-15
Abstract
Abstract Solid state electronic devices are optically monitored during fabrication to detect hot spots which are indicative of faulty operation. The surface temperatures of such a device are measured by applying a fluorescent material to the device, and subsequently monitoring the temperature dependent fluorescence of the material, which is reflective of the temperature of the underlying device. Devices are accepted, rejected, or further processed in response to the monitored fluorescence.
Inventors
- 👤 Paul R. Kolodner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:08
CPC Classifications
G; G01; G01K; G01K11/00; G01K11/20; G01N; G01N25/00; G01N25/72
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
91 words
A method for fabricating a solid state electronic device, comprising the steps of: forming a layer of fluorescent material on a surface of a partially or fully completed solid state electronic device, the fluorescence of said material varying as the temperature of the underlying device varies; exposing said material to energy which causes said material to fluoresce; monitoring the fluorescence of said material while the solid state electronic device is contacted with a voltage and/or current source; and accepting, rejecting, or further processing said device in response to the monitored fluorescence.
Claim 2
Independent Claim
91 words
A method for fabricating a solid state electronic device, comprising the steps of: forming a layer of fluorescent material on a surface of a partially or fully completed solid state electronic device, the fluorescence of said material varying as the temperature of the underlying device varies; exposing said material to energy which causes said material to fluoresce; monitoring the fluorescence of said material while the solid state electronic device is contacted with a voltage and/or current source; and accepting, rejecting, or further processing said device in response to the monitored fluorescence.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein said layer of material is less than 10 microns thick.
Claim 4
Dependent Claim
16 words
The method of claim 2 wherein said layer of material is less than 5 microns thick.
Claim 5
Dependent Claim
16 words
The method of claim 3 wherein said layer of material is less than 1 micron thick.
Claim 6
Dependent Claim
22 words
The method of claim 1 wherein the fluorescence of said material is detectably responsive to temperature changes less than 10 degrees Celsius.
Claim 7
Dependent Claim
22 words
The method of claim 5 wherein the fluorescence of said material is detectably responsive to temperature changes less than 1 degree Celsius.
Claim 8
Dependent Claim
25 words
The method of claim 6 wherein the fluorescence of said material is detectably responsive to temperature changes less than a tenth of a degree Celsius.
Claim 9
Dependent Claim
25 words
The method of claim 7 wherein the fluorescence of said material is detectably responsive to temperature changes less than a hundredth of a degree Celsius.
Claim 10
Dependent Claim
23 words
The method of claim 1 wherein the spatial resolution of the thermal profile associated with the monitored fluorescence is less than 50 microns.
Claim 11
Dependent Claim
23 words
The method of claim 9 wherein the spatial resolution of the thermal profile associated with the monitored fluorescence is less than 2 microns.
Claim 12
Dependent Claim
26 words
The method of claim 1 wherein the energy which causes the material to fluoresce is ultraviolet light in the spectral range of 300 to 400 nanometers.
Claim 13
Dependent Claim
27 words
The method of claim 1 wherein the monitored fluorescence is normalized to the fluorescence monitored when the device is not contacted with a voltage and/or current source.
Claim 14
Dependent Claim
16 words
The method of claim 1 wherein the material layer comprises Europium Thenoyltrifluoroacetonate (EuTTA) distributed in PMMA.
Claim 15
Dependent Claim
16 words
The method of claim 12 wherein the material layer comprises Europium Thenoyltrifluoroacetonate (EuTTA) distributed in dPMMA.
Claim 16
Dependent Claim
21 words
The method of claim 14 wherein said layer includes about 0.5 to about 40 percent by weight of Europium Thenoyltrifluoroacetonate (EuTTA).
Claim 17
Dependent Claim
28 words
The method of claim 15 wherein the fluorescence intensity of the material layer varies with temperature as approximately a straight line with a slope of approximately -0.05/degree Celsius.
Claim 18
Dependent Claim
29 words
The method of claim 16 wherein said layer is illuminated with approximately 700 microwatts per centimeter squared of UV radiation in the wavelength range from 345 to 380 nanometers.
Claim 19
Dependent Claim
14 words
The method of claim 1 wherein said fluorescence is monitored using a CCD array.
Claim 20
Dependent Claim
14 words
The method of claim 10 wherein said fluorescence is monitored using a CCD array.
Claim 21
Dependent Claim
14 words
The method of claim 15 wherein said fluorescence is monitored using a CCD array.
Claim 22
Dependent Claim
20 words
The method of claim 20 wherein a thermal picture of substantially the entire device is imaged by a CCD array.
Claim 23
Dependent Claim
15 words
The method of claim 1 wherein said material layer comprises EuFOD distributed in a polymer.
Claim 24
Dependent Claim
20 words
The method of claim 22 wherein said layer includes about 2 to about 50 percent by weight of the EuFOD.
Claim 25
Dependent Claim
29 words
The method of claim 1, further comprising the step of producing a thermal transient in said device by delivering power, or increasing the delivery of power, to said device.
Claim 26
Dependent Claim
33 words
The method of claim 24 wherein said exposing step occurs substantially simultaneously with the onset of said thermal transient, and wherein the resulting fluorescence of said material is detected during said monitoring step.
Claim 27
Dependent Claim
50 words
The method of claim 24, wherein said exposing step occurs over a period of time which includes the duration of said thermal transient, and said monitoring step includes the step of gating a detector which detects the fluorescence of said material, substantially simultaneously with the onset of said thermal transient.
Claim 28
Dependent Claim
55 words
The method of claim 25 wherein said layer of fluorescent material has a fluorescence lifetime, τ, which is smaller than t x , the time required for heat to diffuse a preselected distance across the surface of said device, and wherein said exposing step occurs over a period of time less than t x .
Claim 29
Dependent Claim
55 words
The method of claim 26 wherein said layer of fluorescent material has a fluorescence lifetime, τ, which is smaller than t x , the time required for heat to diffuse a preselected distance across the surface of said device, and wherein said detector is gated for a period of time less than t x .
Claim 30
Dependent Claim
21 words
The method of claim 1 wherein said layer of fluorescent material has a fluorescence lifetime which is less than 10 nanoseconds.
Claim 31
Independent Claim
14 words
The method of clainm 29 wherein said material comprises Rhodamine B distributed in polyethyleneimine.
Claim 32
Independent Claim
14 words
The method of clainm 29 wherein said material comprises Rhodamine B distributed in polyethyleneimine.
Claim 33
Dependent Claim
10 words
The method of claim 29 wherein said material comprises bianthrone.
Claim 34
Dependent Claim
10 words
The method of claim 29 wherein said material comprises dimethylaminoazobenzene.
Claim 35
Dependent Claim
10 words
The method of claim 29 wherein said material comprises 9-methylanthracene.
Claim 36
Dependent Claim
13 words
The method of claim 1 wherein said device is an integrated circuit device.
Claim 37
Dependent Claim
12 words
The method of claim 1 wherein said device is a laser diode.
Claim 38
Dependent Claim
13 words
The method of claim 1 wherein said device is a Josephson junction device.
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) | 1987-06-26 | 1987-12-26 | 1988-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-26 | 1991-12-26 | 1992-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-26 | 1995-12-26 | 1996-06-26 | $7700.00 | Window Closed / Lapsed |