Patent US4191938A successfully refreshed from Google Patents.
US4191938A
Expired / Lapsed
US
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Cermet resistor trimming method
Assignee: International Business Machines Corp
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Filing: 1978-07-03
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Granted: 1980-03-04
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Expires: 1998-07-03
Abstract
Abstract A method for laser trimming of resistors which includes sputter depositing or vaporizing resistor material in a limited area but the resistor geometry and trimming location is designed to achieve a maximum resistor trimming range with a minimum substrate area occupied by the resistor. A cermet resistor is fabricated on a metallized ceramic substrate with the resistor having a low length to width ratio. A laser cut is used to provide resistor values greater than 250 ohms and up to 16000 ohms.
Inventors
- 👤 3rd John Gow
- 👤 Herman S. Hoffman
- 👤 Earl Stephans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:55
CPC Classifications
H; H01; H01C; H01C17/00; H01C17/22; H01C17/23; H01C7/00; H01C7/006; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49099
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
56 words
A method of trimming a thin film resistor which comprises the steps of: fabricating on a substrate a thin film resistor material having a low length to width ratio; establishing the sheet resistance of said material at 1000 ohms per square; and laser trimming said material to provide resistor values from 250 ohms to 16000 ohms.
Claim 2
Independent Claim
56 words
A method of trimming a thin film resistor which comprises the steps of: fabricating on a substrate a thin film resistor material having a low length to width ratio; establishing the sheet resistance of said material at 1000 ohms per square; and laser trimming said material to provide resistor values from 250 ohms to 16000 ohms.
Claim 3
Independent Claim
59 words
A method of trimming a thin film resistor which comprises the steps of: fabricating on a substrate a thin film resistor material having a low length to width ratio; establishing the sheet resistance of said material at 1000 ohms per square; and laser trimming said material to vary the number of squares and vary the resistance of said material.
Claim 4
Independent Claim
59 words
A method of trimming a thin film resistor which comprises the steps of: fabricating on a substrate a thin film resistor material having a low length to width ratio; establishing the sheet resistance of said material at 1000 ohms per square; and laser trimming said material to vary the number of squares and vary the resistance of said material.
Claim 5
Dependent Claim
36 words
The method as set forth in claim 2 wherein said thin film resistor material is cermet and the laser trimming is carried out by making laser cuts to vary the number of squares of cermet material.
Claim 6
Independent Claim
74 words
A method of trimming a thin film resistor which comprises the steps of: fabricating on a substrate a thin film cermet resistor material having a low length to width ratio of 1 to 4; establishing the sheet resistance of said cermet material at 1000 ohms per square; and making 0.001 inch wide laser cuts of said cermet material to vary the number of squares of the cermet material and accordingly vary the resistance thereof.
Claim 7
Independent Claim
74 words
A method of trimming a thin film resistor which comprises the steps of: fabricating on a substrate a thin film cermet resistor material having a low length to width ratio of 1 to 4; establishing the sheet resistance of said cermet material at 1000 ohms per square; and making 0.001 inch wide laser cuts of said cermet material to vary the number of squares of the cermet material and accordingly vary the resistance thereof.
Claim 8
Independent Claim
80 words
A method of trimming a thin film resistor which comprises the steps of: fabricating on a substrate a thin film resistor material having a low length to width ratio; establishing the sheet resistance of said material at 1000 ohms per square; fabricating conductive electrodes which contact said resistor material; and laser trimming said resistor material to create a varying number of squares in parallel or in series with said electrodes to provide a range of resistance values for said resistor.
Claim 9
Independent Claim
80 words
A method of trimming a thin film resistor which comprises the steps of: fabricating on a substrate a thin film resistor material having a low length to width ratio; establishing the sheet resistance of said material at 1000 ohms per square; fabricating conductive electrodes which contact said resistor material; and laser trimming said resistor material to create a varying number of squares in parallel or in series with said electrodes to provide a range of resistance values for said resistor.
Claim 10
Independent Claim
87 words
A method of trimming a thin film resistor which comprises the steps of: fabricating on a substrate a thin film resistor of cermet material having a length to width ratio of 1 to 4 to equal 1/4 square; establishing the sheet resistance of said material at 1000 ohms per square; fabricating conductive electrodes which contact said resistor material along the width thereof; and laser trimming said resistor by making linear cuts to selectively increase the number of squares in said resistor and increase the resistance value thereof.
Claim 11
Independent Claim
87 words
A method of trimming a thin film resistor which comprises the steps of: fabricating on a substrate a thin film resistor of cermet material having a length to width ratio of 1 to 4 to equal 1/4 square; establishing the sheet resistance of said material at 1000 ohms per square; fabricating conductive electrodes which contact said resistor material along the width thereof; and laser trimming said resistor by making linear cuts to selectively increase the number of squares in said resistor and increase the resistance value thereof.
Claim 12
Dependent Claim
31 words
The method of trimming as set forth in claim 6 wherein said linear cuts may be made to increase the number of squares in parallel or in series with said electrodes.
Claim 13
Independent Claim
108 words
A method of trimming a thin film resistor which comprises the steps of: fabricating on a substrate a thin film resistor of cermet material having a composition in the range of 70% Cr-30% SiO to 50% Cr-50% SiO and having a length to width ratio of 1 to 4 to equal 1/4 square; fabricating conductive electrodes which contact said resistor material along the width thereof; and laser trimming said resistor by making linear cuts which are operable to create a range of 1/4 square to 16 squares between said electrodes whereby the resistance of said resistor may be adjusted in the range of 250 ohms to 16000 ohms.
Claim 14
Independent Claim
108 words
A method of trimming a thin film resistor which comprises the steps of: fabricating on a substrate a thin film resistor of cermet material having a composition in the range of 70% Cr-30% SiO to 50% Cr-50% SiO and having a length to width ratio of 1 to 4 to equal 1/4 square; fabricating conductive electrodes which contact said resistor material along the width thereof; and laser trimming said resistor by making linear cuts which are operable to create a range of 1/4 square to 16 squares between said electrodes whereby the resistance of said resistor may be adjusted in the range of 250 ohms to 16000 ohms.
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) | 1983-03-04 | 1983-09-03 | 1984-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-04 | 1987-09-03 | 1988-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-04 | 1991-09-03 | 1992-03-04 | $7700.00 | Window Closed / Lapsed |