US4104086A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming isolated regions of silicon utilizing reactive ion etching
Assignee: International Business Machines Corp
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Filing: 1977-08-15
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Granted: 1978-08-01
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Expires: 1997-08-15
Abstract
Abstract A method for isolating regions of silicon involving the formation of openings that have a suitable taper in a block of silicon, thermally oxidizing the surfaces of the openings, and filling the openings with a dielectric material to isolate regions of silicon within the silicon block. The method is particularly useful wherein the openings are made through a region of silicon having a layer of a high doping conductivity.
Inventors
- 👤 James Allan Bondur
- 👤 Hans Bernhard Pogge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:52
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/69; H10P50/691; H10P50/692; H10P50/20; H10P50/24; H10P50/242; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/0145; H10W10/10; H10W10/17; Y; Y10; Y10S; Y10S148/00; Y10S148/051; Y10S148/131; Y10S148/161; Y10S148/168; Y10S438/00; Y10S438/978
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
111 words
A method for isolating regions of silicon comprising: providing a silicon body composed principally of one conductivity; forming tapered sided openings of less than about 4 micrometers in width at the surface in said body by reactive ion etching; the taper of said tapered sided openings being greater than about 2° from the vertical and terminating into the substantially flat bottom of said openings; thermally oxidizing the surfaces of said openings; filling said thermally oxidized openings with a dielectric material wherein the said regions of silicon are isolated; and removing said dielectric material from above the surface of said body wherein the said openings are uniformly filled at the said surface.
Claim 2
Independent Claim
111 words
A method for isolating regions of silicon comprising: providing a silicon body composed principally of one conductivity; forming tapered sided openings of less than about 4 micrometers in width at the surface in said body by reactive ion etching; the taper of said tapered sided openings being greater than about 2° from the vertical and terminating into the substantially flat bottom of said openings; thermally oxidizing the surfaces of said openings; filling said thermally oxidized openings with a dielectric material wherein the said regions of silicon are isolated; and removing said dielectric material from above the surface of said body wherein the said openings are uniformly filled at the said surface.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein said silicon body contains a layer of highly doped silicon and said openings extend through said layer.
Claim 4
Dependent Claim
52 words
The method of claim 2 wherein said openings are formed in a silicon reactive chlorine specie ambient having a pressure of between about 2 and 50 micrometers, said chlorine specie in said ambient being between about 2 and 10 percent, and the etch rate between about 0.03 and 0.08 micrometers per minute.
Claim 5
Dependent Claim
23 words
The method of claim 3 wherein the power applied for said reactive ion etching is between about 0.1 and 0.75 watts/cm 2 .
Claim 6
Dependent Claim
27 words
The method of claim 3 wherein the said chlorine specie is chlorine gas and the said chlorine in said ambient is between about 2 and 8 percent.
Claim 7
Dependent Claim
15 words
The method of claim 3 wherein the remaining gas component of said ambient is argon.
Claim 8
Dependent Claim
17 words
The method of claim 1 wherein said taper is between about 2° to 20° from the vertical.
Claim 9
Dependent Claim
24 words
The method of claim 1 wherein less than 2000 Angstroms of silicon dioxide is formed by said thermally oxidizing the surfaces of said openings.
Claim 10
Dependent Claim
20 words
The method of claim 1 wherein said dielectric layer is silicon dioxide and it is deposited by chemical vapor deposition.
Claim 11
Dependent Claim
18 words
The method of claim 9 wherein between about 1 and 5 micrometers of said dielectric layer is deposited.
Claim 12
Dependent Claim
15 words
The method of claim 1 wherein said dielectric material is removed by reactive ion etching.
Claim 13
Dependent Claim
36 words
The method of claim 1 wherein a silicon dioxide mask is used for said reactive ion etching of silicon and said mask has a tapered silicon dioxide opening of about 5° to 20° from the vertical.
Claim 14
Independent Claim
100 words
A method for isolating regions of silicon comprising: providing a silicon body composed principally of one conductivity and having a layer of highly doped silicon; etching tapered sided openings in said body and through said highly doped layer in a silicon reactive chlorine specie ambient having a pressure of between about 2 to 50 micrometers, chlorine specie of gas between about 2 to 10 percent, and etch rate between about 0.03 and 0.08 micrometers per minute; thermally oxidizing the surfaces of said openings; filling said thermally oxidized openings with a dielectric material wherein the said regions of silicon are isolated.
Claim 15
Independent Claim
100 words
A method for isolating regions of silicon comprising: providing a silicon body composed principally of one conductivity and having a layer of highly doped silicon; etching tapered sided openings in said body and through said highly doped layer in a silicon reactive chlorine specie ambient having a pressure of between about 2 to 50 micrometers, chlorine specie of gas between about 2 to 10 percent, and etch rate between about 0.03 and 0.08 micrometers per minute; thermally oxidizing the surfaces of said openings; filling said thermally oxidized openings with a dielectric material wherein the said regions of silicon are isolated.
Claim 16
Dependent Claim
21 words
The method of claim 13 wherein the power applied for said etching is between about 0.1 to 0.75 watts/cm 2 .
Claim 17
Dependent Claim
26 words
The method of claim 13 wherein the said chlorine specie is chlorine gas and the said chlorine in said ambient is about 2 to 8 percent.
Claim 18
Dependent Claim
14 words
The method of claim 15 wherein the remaining component of said ambient is argon.
Claim 19
Dependent Claim
25 words
The method of claim 13 wherein the said layer of highly doped silicon has a doping level greater than about 2 × 10 19 atoms/cc.
Claim 20
Dependent Claim
16 words
The method of claim 13 wherein said highly doped layer is within the said silicon body.
Claim 21
Dependent Claim
30 words
The method of claim 13 wherein the said dielectric material is removed from above the surface of said body wherein the said openings are uniformly filled at the said surface.
Claim 22
Dependent Claim
29 words
The method of claim 19 wherein a further heating of said structure at a temperature of about 900° to 950° C to improve the structure of said dielectric material.
Claim 23
Dependent Claim
34 words
The method of claim 18 wherein a said layer is N+, said body is P and a P+ implant is made at the bottom of said openings prior to said thermally oxidizing said openings.
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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) | 1981-07-31 | 1982-01-30 | 1982-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-31 | 1986-01-30 | 1986-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-31 | 1990-01-30 | 1990-08-01 | $7700.00 | Window Closed / Lapsed |