US5447884A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shallow trench isolation with thin nitride liner
Assignee: Qimonda AG
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Filing: 1994-06-29
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Granted: 1995-09-05
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Expires: 2014-06-29
Abstract
Abstract A method of forming shallow trench isolation with a nitride liner layer for devices in integrated circuits solves a problem of recessing the nitride liner that led to unacceptable voids in the trench filler material by using a liner thickness of less than 5 nm. A densification step of a pyrogenic oxide anneal at 800° C. not only drives out impurities and achieves the same density as a conventional argon anneal at 1000° C., but also drastically reduces the thermal load.
Inventors
- 👤 Paul M. Fahey
- 👤 Erwin Hammerl
- 👤 Herbert L. Ho
- 👤 Mutsuo Morikado
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:24
CPC Classifications
H; H10; H10P; H10P95/00; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/0145; H10W10/10; H10W10/17; Y; Y10; Y10S; Y10S148/00; Y10S148/05
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
138 words
A method of forming isolation members embedded in a silicon layer of an integrated circuit comprising the steps of: depositing a protective layer containing at least one layer of nitride on a top surface of a silicon layer; etching through said protective layer to form a set of isolation mask apertures; etching through said set of isolation mask apertures in a reactive ion etch process to form a set of isolation trenches; depositing a conformal layer of nitride having a thickness less than 5 nm; depositing a CVD layer of oxide having a thickness sufficient to fill said set of isolation trenches; removing that portion of said CVD layer of oxide outside said set of isolation trenches to expose said at least one layer of nitride; and stripping said at least one layer of nitride in phosphoric acid.
Claim 2
Independent Claim
138 words
A method of forming isolation members embedded in a silicon layer of an integrated circuit comprising the steps of: depositing a protective layer containing at least one layer of nitride on a top surface of a silicon layer; etching through said protective layer to form a set of isolation mask apertures; etching through said set of isolation mask apertures in a reactive ion etch process to form a set of isolation trenches; depositing a conformal layer of nitride having a thickness less than 5 nm; depositing a CVD layer of oxide having a thickness sufficient to fill said set of isolation trenches; removing that portion of said CVD layer of oxide outside said set of isolation trenches to expose said at least one layer of nitride; and stripping said at least one layer of nitride in phosphoric acid.
Claim 3
Dependent Claim
31 words
A method according to claim 1, in which said step of filling said trench is followed by a step of annealing said CVD layer of oxide in a pyrogenic oxidation anneal.
Claim 4
Dependent Claim
45 words
A method according to claim 2, in which said step of filling said trench comprises ozone-assisted deposition of TEOS and in which said step of annealing said CVD layer of oxide in a pyrogenic oxidation anneal drives out fluorine from said CVD layer of oxide.
Claim 5
Dependent Claim
24 words
A method according to claim 1, in which said step of filling said trench is conducted at a temperature of less than 800° C.
Claim 6
Dependent Claim
31 words
A method according to claim 4, in which said step of filling said trench is followed by a step of annealing said CVD layer of oxide in a pyrogenic oxidation anneal.
Claim 7
Dependent Claim
45 words
A method according to claim 5, in which said step of filling said trench comprises ozone-assisted deposition of TEOS and in which said step of annealing said CVD layer of oxide in a pyrogenic oxidation anneal drives out fluorine from said CVD layer of oxide.
Claim 8
Dependent Claim
30 words
A method according to claim 1, in which said step of depositing a conformal layer of nitride is preceded by a step of growing a thin layer of thermal oxide.
Claim 9
Dependent Claim
31 words
A method according to claim 7, in which said step of filling said trench is followed by a step of annealing said CVD layer of oxide in a pyrogenic oxidation anneal.
Claim 10
Dependent Claim
45 words
A method according to claim 8, in which said step of filling said trench comprises ozone-assisted deposition of TEOS and in which said step of annealing said CVD layer of oxide in a pyrogenic oxidation anneal drives out fluorine from said CVD layer of oxide.
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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) | 1998-09-04 | 1999-03-06 | 1999-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-09-04 | 2003-03-06 | 2003-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-09-04 | 2007-03-06 | 2007-09-05 | $7700.00 | Window Closed / Lapsed |