US3864825A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making thin-film microelectronic resistors
Assignee: Microsystems International Ltd
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Filing: 1973-11-12
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Granted: 1975-02-11
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Expires: 1993-11-12
Abstract
Abstract The present disclosure relates to a number of layers of resistive materials superimposed upon an area of the substrate, the material of highest resistivity being deposited first, and therefore at the bottom of the stack, and the remaining layers being deposited in decreasing order of resistivity. Thereafter the layers are selectively trimmed to give required values.
Inventors
- 👤 Edward S B Holmes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:34
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/006; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49099; Y10T29/49101
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
146 words
A method of forming a plurality of resistors upon a surface of a substrate member, comprising the steps of; a. depositing upon the surface of said substrate member a stack of n layers of electrically conductive material of differing resistivity, where n is an integer greater than one, said layers being deposited in decreasing order of resistivity of the layer materials; b. defining the required areal geometry of each of said plurality of resistors and isolating each of said plurality of resistors by masking and subsequently chemically removing said n layers of electrically conductive material from the surface of the substrate adjacent and exterior to the perimeter of each of said resistors; c. forming spaced apart terminal means for each of said resistors, the terminal means corresponding to each of said resistors being electrically connected to the top electrically conductive layer of each of said resistors.
Claim 2
Independent Claim
146 words
A method of forming a plurality of resistors upon a surface of a substrate member, comprising the steps of; a. depositing upon the surface of said substrate member a stack of n layers of electrically conductive material of differing resistivity, where n is an integer greater than one, said layers being deposited in decreasing order of resistivity of the layer materials; b. defining the required areal geometry of each of said plurality of resistors and isolating each of said plurality of resistors by masking and subsequently chemically removing said n layers of electrically conductive material from the surface of the substrate adjacent and exterior to the perimeter of each of said resistors; c. forming spaced apart terminal means for each of said resistors, the terminal means corresponding to each of said resistors being electrically connected to the top electrically conductive layer of each of said resistors.
Claim 3
Dependent Claim
50 words
The method of claim 1 which further comprises chemically removing at least part of the areal geometry of at least one layer from one of said plurality of resistors to provide an electrically conductive path of a required resistance value between the spaced apart terminal means associated with said resistor.
Claim 4
Dependent Claim
31 words
The method of claim 1 wherein n is two, the firstly deposited layer adjacent said substrate member being nichrome and the secondly deposited layer remote from said substrate member being tantalum.
Claim 5
Dependent Claim
31 words
The method of claim 1 wherein n is two, the firstly deposited layer adjacent said substrate member being chromium, and the secondly deposited layer remote from said substrate member being tantalum.
Claim 6
Dependent Claim
38 words
The method of claim 4 which comprises evaporating chromium onto a substrate surface to form a first resistive layer, baking said first resistive layer and sputtering tantalum onto said first resistive layer to form a second resistive layer.
Claim 7
Dependent Claim
30 words
The method of claim 5 which comprises trimming one or both of said resistive layers to provide an electrically conductive path between said terminal means of a required resistance value.
Claim 8
Dependent Claim
58 words
The method of claim 2 wherein at least part of the areal geometry of at least one layer of one of said plurality of resistors is removed simultaneously with the removal of one of said n layers of electrical conductor material from the surface of the substrate adjacent and exterior to the perimeter of each of said resistors.
Claim 9
Dependent Claim
33 words
The method as defined in claim 1 wherein the electrically conductive materials of any one of said deposited layers is chromium and the electrically conductive material of the next overlying layer is tantalum.
Claim 10
Dependent Claim
33 words
The method as defined in claim 1 wherein the electrically conductive material of any one of said deposited layers is nichrome and the electrically conductive material of the next overlying layer is tantalum.
Claim 11
Independent Claim
120 words
A method of forming a plurality of resistors upon a surface of a substrate member, comprising the steps of: a. depositing upon the surface of said substrate member a stack of n layers of electrically resistive material of differing resistivity, where n is an integer greater than one, said layers being deposited in decreasing order of resistivity from the substrate member, b. defining the required areal geometry of each resistor of said plurality of removing said n layers from the surface of the substrate exterior to said resistors, c. defining the ohmic values of each of said resistors by removing m-1 of said layers of predetermined ones of said resistors, where m is a number between 1 and n inclusive.
Claim 12
Independent Claim
120 words
A method of forming a plurality of resistors upon a surface of a substrate member, comprising the steps of: a. depositing upon the surface of said substrate member a stack of n layers of electrically resistive material of differing resistivity, where n is an integer greater than one, said layers being deposited in decreasing order of resistivity from the substrate member, b. defining the required areal geometry of each resistor of said plurality of removing said n layers from the surface of the substrate exterior to said resistors, c. defining the ohmic values of each of said resistors by removing m-1 of said layers of predetermined ones of said resistors, where m is a number between 1 and n inclusive.
Claim 13
Dependent Claim
58 words
The method of claim 10 wherein at least part of the areal geometry of at least one layer, of one of said plurality of resistors is removed simultaneously with the removal of one of said n layers of electrically resistive material from the surface of the substrate adjacent and exterior to the perimeter of each of said resistors.
Claim 14
Dependent Claim
38 words
The method of claim 11 which comprises evaporating chromium onto a substrate surface to form a first resistive layer, baking said first resistive layer and sputtering tantalum onto said first resistive layer to form a second resistive layer.
Claim 15
Dependent Claim
35 words
The method of claim 10 comprising the additional step of trimming one or more of said resistive layers in each of said resistors to provide electrically resistive paths between terminals thereof, of required resistance values.
Claim 16
Dependent Claim
36 words
The method as defined in claim 10 wherein chromium is deposited as the electrically resistive material of any one of said layers and tantalum is deposited as the electrically resistive material of the next overlying layer.
Claim 17
Dependent Claim
36 words
The method as defined in claim 10 wherein nichrome is deposited as the electrically resistive material of any one of said layers and tantalum is deposited as the electrically resistive material of the next overlying layer.
Claim 18
Dependent Claim
32 words
The method of claim 11 in which the step of removing up to m-1 of said layers is a chemical etch, through a mask aperture, of each said layer to be removed.
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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) | 1978-02-10 | 1978-08-12 | 1979-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-10 | 1982-08-12 | 1983-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-10 | 1986-08-12 | 1987-02-11 | $7700.00 | Window Closed / Lapsed |