Patent US4952274A successfully refreshed from Google Patents.
US4952274A
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Method for planarizing an insulating layer
Assignee: Nortel Networks Ltd
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Filing: 1988-05-27
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Granted: 1990-08-28
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Expires: 2008-05-27
Abstract
Abstract In a method for planarizing an insulating layer, the height of steps in a layer of insulating material are reduced while tapering side walls of the steps by forming a layer of sacrificial material between the steps and etching the insulating material and the sacrificial material in a low pressure plasma comprising reactive ions and facetting ions. This method combines many of the advantages of Resist Etch Back (REB) and argon facetting techniques while reducing the deleterious effects of macroloading and microloading.
Inventors
- 👤 Thomas Abraham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:01
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/20; G03F7/24; H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10P95/00; H10P95/06; H10P95/062; H10P95/064
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
60 words
A method for reducing the height of steps in a layer of insulating material while tapering side walls of the steps, the method comprising: forming a layer of sacrificial material between the steps; and etching the insulating material and the sacrificial material in a plasma comprising reactive ions and facetting ions at a pressure between 8 mtorr and 20 mtorr.
Claim 2
Independent Claim
60 words
A method for reducing the height of steps in a layer of insulating material while tapering side walls of the steps, the method comprising: forming a layer of sacrificial material between the steps; and etching the insulating material and the sacrificial material in a plasma comprising reactive ions and facetting ions at a pressure between 8 mtorr and 20 mtorr.
Claim 3
Dependent Claim
25 words
A method as defined in claim 1, comprising forming the layer of sacrificial material with a thickness substantially equal to the height of the steps.
Claim 4
Dependent Claim
55 words
A method as defined in claim 2, comprising forming the layer of sacrificial material between the steps by: forming a layer of sacrificial material having a substantially planar upper surface overlying the entire layer of insulating material; and uniformly removing sacrificial material from the substantially planar upper surface to expose upper surfaces of the steps.
Claim 5
Dependent Claim
22 words
A method as defined in claim 3, comprising uniformly removing material from the substantially planar upper surface by etching the upper surface.
Claim 6
Dependent Claim
21 words
A method as defined in claim 4, comprising uniformly removing material from the substantially planar upper surface by reactive ion etching.
Claim 7
Dependent Claim
17 words
A method as defined in claim 1, comprising etching the sacrificial material faster than the insulating material.
Claim 8
Dependent Claim
20 words
A method as defined in claim 6, comprising etching the sacrificial material up to 50% faster than the insulating material.
Claim 9
Dependent Claim
18 words
A method as defined in claim 7, comprising etching the sacrificial material 25% faster than the insulating material.
Claim 10
Dependent Claim
15 words
A method as defined in claim 1, wherein the facetting ions comprise inert gas ions.
Claim 11
Independent Claim
60 words
A method for reducing the height of steps in a layer of SiO 2 while tapering side walls of the steps, the method comprising: forming a layer of photoresist between the steps; and etching the SiO 2 and the photoresist in a plasma comprising reactive ions and inert gas facetting ions at a pressure between 8 mtorr and 20 mtorr.
Claim 12
Independent Claim
60 words
A method for reducing the height of steps in a layer of SiO 2 while tapering side walls of the steps, the method comprising: forming a layer of photoresist between the steps; and etching the SiO 2 and the photoresist in a plasma comprising reactive ions and inert gas facetting ions at a pressure between 8 mtorr and 20 mtorr.
Claim 13
Dependent Claim
51 words
A method as defined in claim 10, comprising forming the layer of photoresist between the steps by: forming a layer of photoresist having a substantially planar upper surface overlying the entire layer of SiO 2 ; and uniformly etching the substantially planar upper surface to expose upper surfaces of the steps.
Claim 14
Dependent Claim
21 words
A method as defined in claim 11, comprising uniformly removing material from the substantially planar upper surface by reactive ion etching.
Claim 15
Dependent Claim
20 words
A method as defined in claim 12, comprising etching the photoresist up to 50% faster than the SiO 2 .
Claim 16
Dependent Claim
18 words
A method as defined in claim 13, comprising etching the photoresist 25% faster than the SiO 2 .
Claim 17
Dependent Claim
30 words
A method as defined in claim 10, wherein the reactive ions comprise ions of O 2 and CHF 3 , and the inert gas facetting ions comprise ions of Ar.
Claim 18
Dependent Claim
33 words
A method as defined in claim 15, comprising etching the photoresist and SiO 2 in a mixture comprising 5 parts O 2 , 3 parts CHF 3 and 3 to 8 parts Ar.
Claim 19
Independent Claim
77 words
A method for reducing the height of steps in a layer of SiO 2 while tapering side walls of the steps, the method comprising: forming a layer of photoresist between the steps; and etching the SiO 2 and the photoresist in a mixture comprising 5 part O 2 , 3 parts CHF 3 and 3 to 8 parts Ar at a pressure between 8 mtorr and 20 mtorr, and a power between 900 watts and 1300 watts.
Claim 20
Independent Claim
77 words
A method for reducing the height of steps in a layer of SiO 2 while tapering side walls of the steps, the method comprising: forming a layer of photoresist between the steps; and etching the SiO 2 and the photoresist in a mixture comprising 5 part O 2 , 3 parts CHF 3 and 3 to 8 parts Ar at a pressure between 8 mtorr and 20 mtorr, and a power between 900 watts and 1300 watts.
Claim 21
Independent Claim
71 words
A method for reducing the height of steps in a layer of SiO 2 while tapering side walls of the steps, the method comprising: forming a layer of photoresist between the steps; and reactive ion etching the SiO 2 and the photoresist in a mixture comprising 5 parts O 2 , 3 parts CHF 3 and 4 parts Ar at a pressure of 15 mtorr and a power of 1100 watts.
Claim 22
Independent Claim
71 words
A method for reducing the height of steps in a layer of SiO 2 while tapering side walls of the steps, the method comprising: forming a layer of photoresist between the steps; and reactive ion etching the SiO 2 and the photoresist in a mixture comprising 5 parts O 2 , 3 parts CHF 3 and 4 parts Ar at a pressure of 15 mtorr and a power of 1100 watts.
Claim 23
Independent Claim
72 words
A method for reducing the height of steps in a layer of SiO 2 while tapering side walls of the steps, the method comprising: forming a layer of photoresist between the steps; and reactive ion etching the SiO 2 and the photoresist in a gaseous flow comprising 25 sccm O 2 , 15 sccm CHF 3 and 20 sccm Ar at a pressure of 15 mtorr and a power of 1100 watts.
Claim 24
Independent Claim
72 words
A method for reducing the height of steps in a layer of SiO 2 while tapering side walls of the steps, the method comprising: forming a layer of photoresist between the steps; and reactive ion etching the SiO 2 and the photoresist in a gaseous flow comprising 25 sccm O 2 , 15 sccm CHF 3 and 20 sccm Ar at a pressure of 15 mtorr and a power of 1100 watts.
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) | 1993-08-27 | 1994-02-26 | 1994-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-27 | 1998-02-26 | 1998-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-27 | 2002-02-26 | 2002-08-28 | $7700.00 | Window Closed / Lapsed |