Patent US3990927A successfully refreshed from Google Patents.
US3990927A
Expired / Lapsed
US
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Method for isolating the components of an integrated circuit
Assignee: Commissariat à l'Énergie Atomique et Aux Énergies Alternatives
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Filing: 1974-11-15
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Granted: 1976-11-09
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Expires: 1994-11-15
Abstract
Abstract The method of isolating integrated circuit components on a conductive silicon wafer having a deep layer isolated from a surface layer consists in forming a first deposit of low density on each surface zone in which an integrated circuit component is to be implanted while leaving an uncoated strip which separates each deposit from adjacent deposits, in forming a channel corresponding to each strip within the surface layer and partly within the deep layer, in performing selective deposition of silica on the entire wafer so as to fill the channels up to the bottom of the first deposits, and in removing the first deposits so as to leave insulating silica walls around the surface zones.
Inventors
- 👤 Michel Montier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:30
CPC Classifications
H; H10; H10P; H10P95/00; H10P76/00; H10P76/40; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/014; H10W10/10; H10W10/13; H10W10/17; Y; Y10; Y10S; Y10S148/00; Y10S148/043; Y10S148/051; Y10S148/085; Y10S148/118; Y10S438/00; Y10S438/914; Y10S438/924
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
181 words
A method of isolation of different components of an integrated circuit formed on a single wafer of conductive silicon having a surface layer and a deep layer electrically isolated from the surface layer, the deep layer having an opposite conductivity to that of the surface layer or being of electrically insulative material the steps of forming a first deposit of a substance on the surface zones of the wafer corresponding to zones in which said components will be implanted with each deposit separated from adjacent deposits by a strip free of deposit, forming a channel directly beneath each of said strips in the surface layer, said channel penetrating slightly into said deep layer, selectively depositing silica on the entire wafer filling each channel level with the bottom portion of said first deposits, said substance producing by oxidation and also by chlorination during the deposition of silica a compound having a density appreciably lower than the density of said substance, and then removing said first deposits by a specific solvent and forming insulating walls around said surface zones by the remaining silica.
Claim 2
Independent Claim
181 words
A method of isolation of different components of an integrated circuit formed on a single wafer of conductive silicon having a surface layer and a deep layer electrically isolated from the surface layer, the deep layer having an opposite conductivity to that of the surface layer or being of electrically insulative material the steps of forming a first deposit of a substance on the surface zones of the wafer corresponding to zones in which said components will be implanted with each deposit separated from adjacent deposits by a strip free of deposit, forming a channel directly beneath each of said strips in the surface layer, said channel penetrating slightly into said deep layer, selectively depositing silica on the entire wafer filling each channel level with the bottom portion of said first deposits, said substance producing by oxidation and also by chlorination during the deposition of silica a compound having a density appreciably lower than the density of said substance, and then removing said first deposits by a specific solvent and forming insulating walls around said surface zones by the remaining silica.
Claim 3
Dependent Claim
19 words
A method according to claim 1, deposition of said substance being uniform, and defining the deposition zones by etching.
Claim 4
Dependent Claim
12 words
A method according to claim 1 said substance being a transition metal.
Claim 5
Dependent Claim
12 words
A method according to claim 3, wherein said transition metal is molybdenum.
Claim 6
Dependent Claim
68 words
A method according to claim 1 including the steps of depositing doped silica on the first deposit, then depositing a uniform deposition of silica in a gas phase and in an oxidizing medium over the entire wafer to swell the substance of said first deposit and to break the portion of silica which covers said substance and then removing said portion by a specific solvent for doped silica.
Claim 7
Dependent Claim
13 words
A method according to claim 5, the doped silica being doped with phosphorus.
Claim 8
Dependent Claim
26 words
A method according to claim 1 including the step of subjecting the substrate to a gas flow containing silane and oxygen to selectively deposit the silica.
Claim 9
Dependent Claim
24 words
A method according to claim 7, the deposition of silica in the gas phase being at a temperature on the order of 400° C.
Claim 10
Dependent Claim
13 words
A method according to claim 7, the gas phase including hydrogen chloride gas.
Claim 11
Dependent Claim
32 words
A method according to claim 9, wherein the mole percentage of hydrogen chloride is on the order of 0.4% and wherein the mole percentage of oxygen is on the order of 2.5%.
Claim 12
Dependent Claim
11 words
A method according to claim 5, the first deposit being molybdenum.
Claim 13
Dependent Claim
11 words
A method according to claim 7, the first deposit being molybdenum.
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) | 1979-11-09 | 1980-05-10 | 1980-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-09 | 1984-05-10 | 1984-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-09 | 1988-05-10 | 1988-11-09 | $7700.00 | Window Closed / Lapsed |