US5284549A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Selective fluorocarbon-based RIE process utilizing a nitrogen additive
Assignee: International Business Machines Corp
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Filing: 1992-01-02
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Granted: 1994-02-08
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Expires: 2012-01-02
Abstract
Abstract A CHF3-based RIE etching process is disclosed using a nitrogen additive to provide high selectivity of SiO2 or PSG to Al2O3, low chamfering of a photoresist mask, and low RIE lag. The process uses a pressure in the range of about 200-1,000 mTorr, and an appropriate RF bias power, selected based on the size of the substrate being etched. The substrate mounting pedestal is preferably maintained at a temperature of about 0 degrees C. Nitrogen can be provided from a nitrogen-containing molecule, or as N2. He gas can be added to the gas mixture to enhance the RIE lag-reducing effect of the nitrogen.
Inventors
- 👤 Michael S. Barnes
- 👤 Melanie M. Chow
- 👤 John C. Forster
- 👤 Michael A. Fury
- 👤 Chang-Ching Kin
- 👤 Harris C. Jones
- 👤 John H. Keller
- 👤 James A. O'Neill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:21
CPC Classifications
C; C03; C03C; C03C15/00; H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; Y; Y10; Y10S; Y10S438/00; Y10S438/97
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
69 words
A method for selectively reactive ion etching SiO 2 over an aluminum oxide etch stop material on a workpiece in an etching chamber, comprising the steps of: introducing a gas mixture including CHF 3 and a nitrogen containing molecule into said chamber at flow rates of between 40 sccm and about 60 sccm; and maintaining said gas mixture at a pressure in the range of 500 to 1,000 mtorr.
Claim 2
Independent Claim
69 words
A method for selectively reactive ion etching SiO 2 over an aluminum oxide etch stop material on a workpiece in an etching chamber, comprising the steps of: introducing a gas mixture including CHF 3 and a nitrogen containing molecule into said chamber at flow rates of between 40 sccm and about 60 sccm; and maintaining said gas mixture at a pressure in the range of 500 to 1,000 mtorr.
Claim 3
Dependent Claim
15 words
The etching process of claim 1 wherein said nitrogen containing molecule is N 2 .
Claim 4
Dependent Claim
24 words
The etching process of claim 1 and further including a pedestal for mounting said workpiece, the temperature of said pedestal being below 0° C.
Claim 5
Dependent Claim
37 words
The etching process of claim 1 wherein: said workpiece consists of a single wafer of 125 mm diameter; and further comprising a source of RF power in the range of about 500-700 watts for exciting said gas-mixture.
Claim 6
Dependent Claim
13 words
The etching process of claim 1 wherein said gas mixture further includes He.
Claim 7
Dependent Claim
24 words
The etching process of claim 1 wherein the gas flow rates of said CHF 3 and N 2 are 40 and 60 sccm, respectively.
References Cited (Backward Citations)
US4741799A
Cited
US4666555A
Cited
US4668338A
Cited
US4767724A
Cited
US4872947A
Cited
US4956043A
Cited
JPS6433323A
Cited
US4904341A
Cited
JPH03204928A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-02-07 | 1997-08-09 | 1998-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-02-07 | 2001-08-09 | 2002-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-02-07 | 2005-08-09 | 2006-02-08 | $7700.00 | Window Closed / Lapsed |