Patent US5626716A successfully refreshed from Google Patents.
US5626716A
Expired / Lapsed
US
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Plasma etching of semiconductors
Assignee: Lam Research Corp
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Filing: 1995-09-29
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Granted: 1997-05-06
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Expires: 2015-09-29
Abstract
Abstract A dry etching process for use in the manufacture of silicon integrated circuit devices uses a mixture of about eight parts neon to one part CHF 3 (Freon 23) to form the etching plasma. The process etches doped oxides of silicon, such as BPSG and BPTEOS, in preference to undoped oxides of silicon, silicon nitride, silicides and silicon.
Inventors
- 👤 William F. Bosch
- 👤 Helen H. Zhu
- 👤 Syed A. Haider
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:12
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
86 words
A dry etching process for use in the manufacture of silicon integrated circuit devices comprising the steps of: positioning in the chamber of a plasma etching apparatus a silicon wafer having a surface layer of a doped oxide of silicon that is to be etched; flowing a mixture consisting essentially of CHF 3 and neon into the chamber; and applying radio frequency energy to the chamber for providing a discharge in the chamber that ionizes the mixture and forms a plasma that etches the surface layer.
Claim 2
Dependent Claim
86 words
A dry etching process for use in the manufacture of silicon integrated circuit devices comprising the steps of: positioning in the chamber of a plasma etching apparatus a silicon wafer having a surface layer of a doped oxide of silicon that is to be etched; flowing a mixture consisting essentially of CHF 3 and neon into the chamber; and applying radio frequency energy to the chamber for providing a discharge in the chamber that ionizes the mixture and forms a plasma that etches the surface layer.
Claim 3
Dependent Claim
24 words
The process of claim 1 in which the gaseous mixture includes between 4 and 16 parts neon to one part CHF 3 by volume.
Claim 4
Dependent Claim
20 words
The process of claim 1 in which the gaseous mixture includes eight parts neon to one part CHF 3 .
Claim 5
Dependent Claim
109 words
A process for the manufacture of silicon integrated circuit devices comprising the steps of: preparing a silicon wafer that includes on a silicon surface a plurality of layers including layers of doped and undoped oxides of silicon; positioning the wafer on one of the two electrodes of a plasma etching apparatus; passing a gaseous mixture consisting essentially of CHF 3 and neon through the apparatus; and applying a radio frequency voltage between the two electrodes of the apparatus for generating a discharge that ionizes the gaseous mixture and creates a plasma that etches selectively layers of doped oxides of silicon in preference to layers of undoped oxides of silicon.
Claim 6
Dependent Claim
109 words
A process for the manufacture of silicon integrated circuit devices comprising the steps of: preparing a silicon wafer that includes on a silicon surface a plurality of layers including layers of doped and undoped oxides of silicon; positioning the wafer on one of the two electrodes of a plasma etching apparatus; passing a gaseous mixture consisting essentially of CHF 3 and neon through the apparatus; and applying a radio frequency voltage between the two electrodes of the apparatus for generating a discharge that ionizes the gaseous mixture and creates a plasma that etches selectively layers of doped oxides of silicon in preference to layers of undoped oxides of silicon.
Claim 7
Dependent Claim
16 words
The process of claim 4 in which the plasma that etches is predominantly reactive ion etching.
Claim 8
Dependent Claim
26 words
The process of claim 4 characterized in that the doped layers are doped with dopants from the group consisting of boron and phosphorus and mixtures thereof.
Claim 9
Dependent Claim
38 words
The process of claim 1 in which the CHF 3 and the neon flow into the chamber at a rates of 400 sccm and 50 sccm, respectively, and the pressure in the chamber is maintained at 100 millitores.
Claim 10
Dependent Claim
18 words
The process of claim 7 in which the r-f energy applied is maintained between 700 and 1100 watts.
Claim 11
Dependent Claim
107 words
A process for etching a silicon wafer that includes surface layers of which one is a layer of silicon nitride and another is a layer of a doped oxide of silicon that is to be etched preferentially to the layer of silicon nitride comprising the steps of: positioning the silicon wafer to be etched in a plasma etching apparatus; and flowing a gaseous medium consisting essentially of a mixture of CHF 3 and neon gas through the apparatus to ionize the gaseous medium and create a plasma that etches preferentially the exposed surface of the doped oxide of silicon layer to form an opening in such layer.
Claim 12
Dependent Claim
107 words
A process for etching a silicon wafer that includes surface layers of which one is a layer of silicon nitride and another is a layer of a doped oxide of silicon that is to be etched preferentially to the layer of silicon nitride comprising the steps of: positioning the silicon wafer to be etched in a plasma etching apparatus; and flowing a gaseous medium consisting essentially of a mixture of CHF 3 and neon gas through the apparatus to ionize the gaseous medium and create a plasma that etches preferentially the exposed surface of the doped oxide of silicon layer to form an opening in such layer.
Claim 13
Dependent Claim
23 words
The process of claim 6 in which the gaseous mixture is between four and sixteen parts neon to one part CHF 3 .
Claim 14
Dependent Claim
25 words
The process of claim 9 in which the gaseous medium being flowed through the apparatus is eight parts neon to one part CHF 3 .
Claim 15
Dependent Claim
30 words
The process of claim 10 in which the layer of doped oxide of silicon is a layer of a silicate glass doped with approximately equal parts of boron and phosphorus.
Claim 16
Dependent Claim
19 words
The process of claim 12 in which boron and phosphorus are each four per cent of the silicate glass.
Claim 17
Dependent Claim
24 words
The process of claim 14 in which the mixture of CHF 3 and neon is eight parts neon and one part CHF 3 .
Claim 18
Dependent Claim
29 words
The process of claim 14 in which the layer of doped oxides of silicon is a layer of a silicate glass doped with equal parts of boron and phosphorus.
Claim 19
Dependent Claim
25 words
The process of claim 14 in which the layer of doped oxides of silicon is doped with four percent boron and four per cent phosphorus.
Claim 20
Dependent Claim
31 words
The process of claim 14 in which the wafer has a diameter of eight inches and the radio frequency energy applied for generating the discharge is between 700 and 1100 watts.
Claim 21
Dependent Claim
56 words
The process of claim 1 in which the silicon wafer being etched includes a surface layer of a doped oxide of silicon and at least one layer of a composition from the group consisting of silicon nitride, undoped oxides of silicon, and oxynitrides, the plasma etching the doped oxide preferentially with respect to the other compositions.
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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) | 2000-05-05 | 2000-11-04 | 2001-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-05-05 | 2004-11-04 | 2005-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-05-05 | 2008-11-04 | 2009-05-06 | $7700.00 | Window Closed / Lapsed |