US5854104A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for fabricating nonvolatile semiconductor memory device having a ferroelectric capacitor
Assignee: Sharp Corp
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Filing: 1997-01-30
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Granted: 1998-12-29
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Expires: 2017-01-30
Abstract
Abstract A process for fabricating a nonvolatile semiconductor memory device has one transistor and one ferroelectric capacitor electrically connected to each other by a contact plug, which comprising forming a transistor; forming an inter-layer insulating film, at least an upper surface portion thereof being a titanium oxide film; forming a capacitor lower electrode; and forming a capacitor insulating film and a capacitor upper electrode, wherein the lower electrode forming step comprises: depositing a titanium nitride film and a platinum film on the titanium oxide film; etching the platinum film with a first etching gas adapted to suppress deposition of substances including platinum; and etching the titanium nitride film with a second etching gas having a high etching selectivity to the titanium oxide film.
Inventors
- 👤 Shigeo Onishi
- 👤 Takao Kinoshita
- 👤 Jun Kudo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:44
CPC Classifications
H; H10; H10B; H10B12/00; C; C23; C23F; C23F4/00; H10B53/00; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/692; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
122 words
A process for fabricating a nonvolatile semiconductor memory device having one transistor and one ferroelectric capacitor electrically connected to each other by a contact plug, which comprising forming a transistor; forming an inter-layer insulating film, at least an upper surface portion thereof being a titanium oxide film; forming a capacitor lower electrode; and forming a capacitor insulating film and a capacitor upper electrode, wherein the lower electrode forming step comprises: depositing a titanium nitride film and a platinum film on the titanium oxide film; etching the platinum film with a first etching gas adapted to suppress deposition of substances including platinum; and etching the titanium nitride film with a second etching gas having a high etching selectivity to the titanium oxide film.
Claim 2
Dependent Claim
122 words
A process for fabricating a nonvolatile semiconductor memory device having one transistor and one ferroelectric capacitor electrically connected to each other by a contact plug, which comprising forming a transistor; forming an inter-layer insulating film, at least an upper surface portion thereof being a titanium oxide film; forming a capacitor lower electrode; and forming a capacitor insulating film and a capacitor upper electrode, wherein the lower electrode forming step comprises: depositing a titanium nitride film and a platinum film on the titanium oxide film; etching the platinum film with a first etching gas adapted to suppress deposition of substances including platinum; and etching the titanium nitride film with a second etching gas having a high etching selectivity to the titanium oxide film.
Claim 3
Dependent Claim
21 words
A process as set forth in claim 1, wherein the first etching gas contains a chlorine-based gas and a fluorine-based gas.
Claim 4
Dependent Claim
41 words
A process as set forth in claim 2, wherein the first etching gas contains chlorine gas, and C n F 2n+2 (n: a natural number), CHF 3 or SiF 4 gas in a volume ratio of about 4/1 to about 1/1.
Claim 5
Dependent Claim
24 words
A process as set forth in claim 1, wherein the second etching gas contains a chlorine-based gas or a fluorine-based gas and oxygen gas.
Claim 6
Dependent Claim
33 words
A process as set forth in claim 4, wherein the second etching gas contains chlorine gas or SF 6 gas, and oxygen gas in a volume ratio of about 50/1 to about 5/1.
Claim 7
Dependent Claim
118 words
A process as set forth in claim 1, wherein the capacitor insulating film/upper electrode forming step comprises: (i) depositing a ferroelectric film, a platinum film, a titanium nitride film and an aluminum film over the entire surface of the inter-layer insulating film including the capacitor lower electrode; (ii) etching the aluminum film and the titanium nitride film with a third etching gas, and etching the platinum film with a fourth etching gas adapted to suppress deposition of substances including platinum for formation of the capacitor upper electrode; and (iii) etching the ferroelectric film with a fifth etching gas less reactive to aluminum by employing the resulting upper electrode as a mask for formation of the capacitor insulating film.
Claim 8
Dependent Claim
19 words
A process as set forth in claim 6, wherein the third etching gas in step (ii) is chlorine gas.
Claim 9
Dependent Claim
24 words
A process as set forth in claim 6, wherein the forth etching gas in step (ii) contains a chlorine-based gas and a fluorine-based gas.
Claim 10
Dependent Claim
42 words
A process as set forth in claim 8, wherein the forth etching gas contains chlorine gas, and C n F 2n+2 (n: a natural number) , CHF 3 or SiF 4 gas in a volume ratio of about 4/1 to about 1/1.
Claim 11
Dependent Claim
26 words
A process as set forth in claim 6, wherein the fifth etching gas in step (iii) contains CF 4 or SF 6 gas, and oxygen gas.
Claim 12
Dependent Claim
35 words
A process as set forth in claim 10, wherein CF 4 or SF 6 gas, and oxygen gas are contained in the fifth etching gas in a volume ratio of about 10/1 to about 3/1.
Claim 13
Dependent Claim
88 words
A process as set forth in claim 1, wherein a contact plug is formed by opening a contact hole in the inter-layer insulating film, depositing a titanium film and a titanium nitride film sequentially over the inter-layer insulating film including the contact hole, depositing a tungsten film on the titanium nitride film so as to fill the contact hole, and etching back the titanium film, the titanium nitride film and the tungsten film by a CMP method to such an extent that the inter-layer insulating film is exposed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-12-28 | 2002-06-29 | 2002-12-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-28 | 2006-06-29 | 2006-12-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-28 | 2010-06-29 | 2010-12-29 | $7700.00 | Window Closed / Lapsed |