US3860465A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for obtaining an accurately determined high resistance in a resistor produced in a single crystalline substrate
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1973-02-01
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Granted: 1975-01-14
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Expires: 1993-02-01
Abstract
Abstract The invention refers to a method for obtaining an accurately determined high resistance in a resistor produced in a single crystalline substrate in the form of a diffused region limited in length, width and depth direction, which region is covered with an oxide layer and is provided with a first and a second window in the oxide layer for connection of two terminal contacts. According to the invention, a third window is made in the oxide layer on the top of the diffused region by means of a conventional photo-resist and etching technique whereupon the diffused region is etched in the depth direction through the third window for a predetermined time period during which such a quantity of material is removed that the resistance of the quantity of material remaining in the diffused region, measured between the first and second window, will be equal to a predetermined resistance value.
Inventors
- 👤 Eva Matzner
- 👤 Olaf Sternbeck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:04
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/40; H10D1/43; H10P; H10P95/00; Y; Y10; Y10S; Y10S148/00; Y10S148/051; Y10S148/085; Y10S148/136
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
141 words
A METHOD FOR OBTAINING AN ACCURATELY DETERMINED HIGH RESISTANCE IN A RESISTOR PRODUCED IN A SINGLE CRYSTALLINE SUBSTRATE IN THE FORM OF A DIFFUSE REGION, LIMITED IN LENGTH, WIDTH AND DEPTH DIRECTION, WHICH REGION IS COVERED WITH AN OXIDE LAYER AND IS PROVIDED WITH A FIRST AND A SECOND WINDOW IN THE OXIDE LAYER FOR CONNECTION OF TWO TERMINAL CONTACTS, THE METHOD COMPRISISNG THE STEPS OF MAKING A THIRD WINDOW IN THE OXIDE LAYER ON THE TOP OF THE DIFFUSED REGION, AND THEN ETCHING THE DIFFUSED REGION IN THE DEPTH DIRECTION THROUGH THE SAID THIRD WINDOW FOR A DETERMINED TIME PERIOD, SAID DETERMINED TIME PERIOD BEING SELECTED SO THAT SUCH QUANTITY OF MATERIAL IS REMOVED THAT THE RESISTANCE OF THE QUANTITY OF MATERIAL REMAINING IN THE DIFFUSE REGION, MEASURED BETWEEN THE FIRST AND SAID SECOND WINDOWS EQUALS A PREDETERMINED RESISTANCE VALUE.
Claim 2
Independent Claim
141 words
A METHOD FOR OBTAINING AN ACCURATELY DETERMINED HIGH RESISTANCE IN A RESISTOR PRODUCED IN A SINGLE CRYSTALLINE SUBSTRATE IN THE FORM OF A DIFFUSE REGION, LIMITED IN LENGTH, WIDTH AND DEPTH DIRECTION, WHICH REGION IS COVERED WITH AN OXIDE LAYER AND IS PROVIDED WITH A FIRST AND A SECOND WINDOW IN THE OXIDE LAYER FOR CONNECTION OF TWO TERMINAL CONTACTS, THE METHOD COMPRISISNG THE STEPS OF MAKING A THIRD WINDOW IN THE OXIDE LAYER ON THE TOP OF THE DIFFUSED REGION, AND THEN ETCHING THE DIFFUSED REGION IN THE DEPTH DIRECTION THROUGH THE SAID THIRD WINDOW FOR A DETERMINED TIME PERIOD, SAID DETERMINED TIME PERIOD BEING SELECTED SO THAT SUCH QUANTITY OF MATERIAL IS REMOVED THAT THE RESISTANCE OF THE QUANTITY OF MATERIAL REMAINING IN THE DIFFUSE REGION, MEASURED BETWEEN THE FIRST AND SAID SECOND WINDOWS EQUALS A PREDETERMINED RESISTANCE VALUE.
Claim 3
Dependent Claim
34 words
The method according to claim 1 wherein said third window covers the entire width of the diffused region as well as the greater part of its length between the first and said second windows.
Claim 4
Dependent Claim
45 words
The method according to claim 1 wherein said third window has such a plane geometric pattern that upon the etching in the depth direction of the diffused region, a number of resistance strips connected in parallel between the first and said second window are formed.
Claim 5
Dependent Claim
45 words
The method according tO claim 1 wherein said third window has such a plane geometric pattern that upon the etching in the depth direction of the diffused region, a number of resistance strips connected in series between the first and said second windows are formed.
Claim 6
Dependent Claim
84 words
The method according to claim 1 wherein the removal of material from the diffused region is made in steps by alternatively etching the diffused region and measuring the resistance value in order to bring the resistance between the first and said second windows with successively smaller and smaller partial amounts nearer to the predetermined resistance value, and when the finally obtained resistance value is attained stabilizing the resistor against changes in time by coating the substrate with silicon dioxide at a relatively low temperature.
References Cited (Backward Citations)
US3432920A
Cited
US3764409A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-13 | 1978-07-15 | 1979-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-13 | 1982-07-15 | 1983-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-13 | 1986-07-15 | 1987-01-14 | $7700.00 | Window Closed / Lapsed |