US3786557A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fabrication of thin film resistors
Assignee: Individual
•
Filing: 1972-05-22
•
Granted: 1974-01-22
•
Expires: 1992-05-22
Abstract
Abstract A method of fabricating thin film resistors is disclosed including the step of trimming the resistors to their final values by heating a resistance layer from which all the resistors are formed for a predetermined time to ensure that each resistance value will fall within a range appropriate to that resistor. The time of heating is determined by first separately determining the heating time required to bring each individual resistor within its appropriate range. A time period which overlaps at least a portion of each individual time period is then selected as the heating time.
Inventors
- 👤 G Bodway
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:05
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H01; H01C; H01C17/00; H01C17/22; H01C17/26; H01C17/265; H10D86/00; H10D86/01; H10D86/03; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49099
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
158 words
A method for fabricating a plurality of thin film resistors, each resistor having a resistance value within a predetermined range of values, said method comprising the steps of: forming a film of resistive material on an insulating substrate, the sheet resistivity of said film being lower than the ultimate resistivity required for any of said resistors; plating electrical connections onto said rEsistive layer; heating said substrate for a first time period to stabilize said film of resistive material; determining a plurality of associated time periods for a subsequent heating necessary to raise the resistance of associated ones of said plurality of resistors to a value within said predetermined range of values; and heating said substrate for a second time period, said second time period having at least some overlap with a portion of each of said associated time periods, to thereby simultaneously trim all of said resistors to their ultimate values lying within said predetermined range of values.
Claim 2
Independent Claim
158 words
A method for fabricating a plurality of thin film resistors, each resistor having a resistance value within a predetermined range of values, said method comprising the steps of: forming a film of resistive material on an insulating substrate, the sheet resistivity of said film being lower than the ultimate resistivity required for any of said resistors; plating electrical connections onto said rEsistive layer; heating said substrate for a first time period to stabilize said film of resistive material; determining a plurality of associated time periods for a subsequent heating necessary to raise the resistance of associated ones of said plurality of resistors to a value within said predetermined range of values; and heating said substrate for a second time period, said second time period having at least some overlap with a portion of each of said associated time periods, to thereby simultaneously trim all of said resistors to their ultimate values lying within said predetermined range of values.
References Cited (Backward Citations)
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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) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |