US6235626B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming a gate electrode using an insulating film with an opening pattern
Assignee: NEC Corp
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Filing: 1998-11-30
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Granted: 2001-05-22
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Expires: 2018-11-30
Abstract
Abstract The present invention provides a method of forming a gate recess in an insulating film on a substrate for depositing a gate electrode film being in contact with a part of the substrate and also extending at least within the gate recess. The method comprises the steps of: forming an etching mask pattern with a first opening pattern on the insulating film; carrying out a first anisotropic etching process by use of the etching mask pattern at a first selective ratio of the etching mask pattern to the insulating film, thereby to form a first recessed portion having a bottom which lies at a first level higher than an interface level between the insulating film and the substrate; and carrying out a second anisotropic etching process by use of the etching mask pattern again at a second selective ratio of the etching mask pattern to the insulating film, wherein the second selective ratio is higher than the first selective ratio, thereby to form a gate recess which comprises a second recessed portion both having a bottom which lies at the interface level and having first side walls of a first oblique angle and a third recessed portion both having a bottom united with a top of the second recessed portion and having second side walls of a second oblique angle which is smaller than the first oblique angle.
Inventors
- 👤 Yoichi Makino
- 👤 Hironobu Miyamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:02
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/012; H10D64/0124; H10D64/0125; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/081; H10W20/082
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
224 words
A method of forming a gate recess in an insulating film on a substrate for depositing a gate electrode film being in contact with a part of said substrate and also extending at least within said gate recess, said method comprising the steps of: forming an etching mask pattern with a first opening pattern on said insulating film; carrying out a first anisotropic etching process by use of said etching mask pattern at a first selective ratio of said etching mask pattern to said insulating film, thereby to form a first recessed portion having a bottom which lies at a first level higher than an interface level between said insulating film and said substrate; and carrying out a second anisotropic etching process by use of said etching mask pattern again at a second selective ratio of said etching mask pattern to said insulating film, wherein said second selective ratio is higher than said first selective ratio, thereby to form a gate recess which comprises a second recessed portion both having a bottom which lies at said interface level and having first side walls of a first oblique angle and a third recessed portion both having a bottom united with a top of said second recessed portion and having second side walls of a second oblique angle which is smaller than said first oblique angle.
Claim 2
Independent Claim
224 words
A method of forming a gate recess in an insulating film on a substrate for depositing a gate electrode film being in contact with a part of said substrate and also extending at least within said gate recess, said method comprising the steps of: forming an etching mask pattern with a first opening pattern on said insulating film; carrying out a first anisotropic etching process by use of said etching mask pattern at a first selective ratio of said etching mask pattern to said insulating film, thereby to form a first recessed portion having a bottom which lies at a first level higher than an interface level between said insulating film and said substrate; and carrying out a second anisotropic etching process by use of said etching mask pattern again at a second selective ratio of said etching mask pattern to said insulating film, wherein said second selective ratio is higher than said first selective ratio, thereby to form a gate recess which comprises a second recessed portion both having a bottom which lies at said interface level and having first side walls of a first oblique angle and a third recessed portion both having a bottom united with a top of said second recessed portion and having second side walls of a second oblique angle which is smaller than said first oblique angle.
Claim 3
Dependent Claim
38 words
The method as claimed in claim 1 , wherein said first selective ratio of said first anisotropic etching process is less than 1, whilst said second selective ratio of said second anisotropic etching process is more than 1.
Claim 4
Dependent Claim
32 words
The method as claimed in claim 2 , wherein said first oblique angle is in the range of 75-90 degrees whilst said second oblique angle is in the range of 45-70 degrees.
Claim 5
Dependent Claim
52 words
The method as claimed in claim 1 , wherein said level of said bottom of said first recessed portion is not larger than a width of said bottom of said first recessed portion so that said bottom of said second recessed portion reaches said interface level upon said second anisotropic etching process.
Claim 6
Dependent Claim
37 words
The method as claimed in claim 1 , wherein a depth of said second recessed portion is larger than zero and not larger than a double of a width of said bottom of said first recessed portion.
Claim 7
Dependent Claim
22 words
The method as claimed in claim 1 , wherein an aspect ratio of said second recessed portion is not larger than 2.
Claim 8
Dependent Claim
22 words
The method as claimed in claim 6 , wherein an aspect ratio of said second recessed portion is not larger than 1.
Claim 9
Dependent Claim
27 words
The method as claimed in claim 1 , wherein said first opening pattern of said etching mask pattern has a size of not more than 0.4 micrometers.
Claim 10
Dependent Claim
20 words
The method as claimed in claim 1 , wherein said etching mask pattern is made of an organic resist material.
Claim 11
Dependent Claim
18 words
The method as claimed in claim 1 , wherein said etching mask pattern is made of a metal.
Claim 12
Independent Claim
214 words
A method of forming a gate electrode, comprising the steps of: forming an etching mask pattern with a first opening pattern on an insulating film on a substrate; carrying out a first arisotropic etching process by use of said etching mask pattern at a first selective ratio of said etching mask pattern to said insulating film, thereby to form a first recessed portion having a bottom which lies at a first level higher than an interface level between said insulating film and said substrate; carrying out a second anisotropic etching process by use of said etching mask pattern again at a second selective ratio of said etching mask pattern to said insulating film, wherein said second selective ratio is higher than said first selective ratio, thereby to form a gate recess which comprises a second recessed portion both having a bottom which lies at said interface level and having first side walls of a first oblique angle and a third recessed portion both having a bottom united with a top of said second recessed portion and having second side walls of a second oblique angle which is smaller than said first oblique angle; and forming a gate electrode film being in contact with said substrate and also extending at least within said gate recess.
Claim 13
Independent Claim
214 words
A method of forming a gate electrode, comprising the steps of: forming an etching mask pattern with a first opening pattern on an insulating film on a substrate; carrying out a first arisotropic etching process by use of said etching mask pattern at a first selective ratio of said etching mask pattern to said insulating film, thereby to form a first recessed portion having a bottom which lies at a first level higher than an interface level between said insulating film and said substrate; carrying out a second anisotropic etching process by use of said etching mask pattern again at a second selective ratio of said etching mask pattern to said insulating film, wherein said second selective ratio is higher than said first selective ratio, thereby to form a gate recess which comprises a second recessed portion both having a bottom which lies at said interface level and having first side walls of a first oblique angle and a third recessed portion both having a bottom united with a top of said second recessed portion and having second side walls of a second oblique angle which is smaller than said first oblique angle; and forming a gate electrode film being in contact with said substrate and also extending at least within said gate recess.
Claim 14
Dependent Claim
38 words
The method as claimed in claim 11 , wherein said first selective ratio of said first anisotropic etching process is less than 1, whilst said second selective ratio of said second anisotropic etching process is more than 1.
Claim 15
Dependent Claim
32 words
The method as claimed in claim 12 , wherein said first oblique angle is in the range of 75-90 degrees whilst said second oblique angle is in the range of 45-70 degrees.
Claim 16
Dependent Claim
52 words
The method as claimed in claim 11 , wherein said level of said bottom of said first recessed portion is not larger than a width of said bottom of said first recessed portion so that said bottom of said second recessed portion reaches said interface level upon said second anisotropic etching process.
Claim 17
Dependent Claim
37 words
The method as claimed in claim 11 , wherein a depth of said second recessed portion is larger than zero and not larger than a double of a width of said bottom of said first recessed portion.
Claim 18
Dependent Claim
22 words
The method as claimed in claim 11 , wherein an aspect ratio of said second recessed portion is not larger than 2.
Claim 19
Dependent Claim
22 words
The method as claimed in claim 16 , wherein an aspect ratio of said second recessed portion is not larger than 1.
Claim 20
Dependent Claim
27 words
The method as claimed in claim 11 , wherein said first opening pattern of said etching mask pattern has a size of not more than 0.4 micrometers.
Claim 21
Dependent Claim
20 words
The method as claimed in claim 11 , wherein said etching mask pattern is made of an organic resist material.
Claim 22
Dependent Claim
18 words
The method as claimed in claim 11 , wherein said etching mask pattern is made of a metal.
Claim 23
Dependent Claim
26 words
The method as claimed in claim 11 , further comprising a step of removing at least underlying parts of said insulation film under said gate electrode.
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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) | 2004-05-21 | 2004-11-20 | 2005-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-05-21 | 2008-11-20 | 2009-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-05-21 | 2012-11-20 | 2013-05-22 | $7700.00 | Window Closed / Lapsed |