US6071817A
Expired / Lapsed
US
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Isolation method utilizing a high pressure oxidation
Assignee: Bell Semiconductor LLC
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Filing: 1998-03-23
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Granted: 2000-06-06
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Expires: 2018-03-23
Abstract
Abstract The present invention applies a silicon nitride or the like as a mask over portions of a substrate, such as an active region, where oxide growth is undesired. Thereafter, without the formation of a recess in the substrate, a high pressure oxidation process is used to grow an oxide, preferably in a furnace. The oxide thus grows into the non-masked areas of the substrate, as well as over the silicon nitride used as a mask. Thereafter, a chemical-mechanical polish is used to etch away undesired oxide, with the silicon nitride being used as an endpoint to terminate the polish operation.
Inventors
- 👤 Derryl D. J. Allman
- 👤 Kenneth P. Fuchs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:08
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6322; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/0121; H10W10/10; H10W10/13; H10P14/6304; H10P14/6306; H10P14/6308; H10P14/6309
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
105 words
A method of forming an oxidation layer in a substrate comprising the steps of: applying a protective layer as a mask to portions of a top surface of said substrate where oxidation is to be prevented to obtain a masked surface having unmasked portions, said protective layer being capable of withstanding a chemical mechanical polishing; oxidizing said masked surface so that oxide regions are created within said substrate at locations corresponding to said unmasked portions; and removing a top portion of said oxide regions using a chemical-mechanical polishing operation and a pad to obtain isolation regions, wherein pad support is provided by said protective layer.
Claim 2
Independent Claim
105 words
A method of forming an oxidation layer in a substrate comprising the steps of: applying a protective layer as a mask to portions of a top surface of said substrate where oxidation is to be prevented to obtain a masked surface having unmasked portions, said protective layer being capable of withstanding a chemical mechanical polishing; oxidizing said masked surface so that oxide regions are created within said substrate at locations corresponding to said unmasked portions; and removing a top portion of said oxide regions using a chemical-mechanical polishing operation and a pad to obtain isolation regions, wherein pad support is provided by said protective layer.
Claim 3
Dependent Claim
32 words
A method according to claim 1 wherein said protective layer is comprised of silicon nitride, said substrate is silicon, and a buffer layer is disposed between said protective layer and said substrate.
Claim 4
Dependent Claim
27 words
A method according to claim 1 wherein said step of oxidizing uses a high pressure oxidation process in which said oxidation pressure is greater than 2 atmospheres.
Claim 5
Dependent Claim
24 words
A method according to claim 3 wherein said oxidizing step grows said oxide regions using a temperature that is less than 1100 degrees F.
Claim 6
Dependent Claim
17 words
A method according to claim 4 wherein said oxidizing step takes 2 to 600 minutes to complete.
Claim 7
Dependent Claim
17 words
A method according to claim 4 wherein said oxidizing step takes 20 to 60 minutes to complete.
Claim 8
Dependent Claim
26 words
A method according to claim 1, wherein said substrate is a wafer, and said protective layer is substantially uniformally disposed over various locations on said wafer.
Claim 9
Dependent Claim
33 words
A method according to claim 7 wherein said step of applying said protective layer results in unmasked portions having length and width dimensions that are larger than a thickness of said isolation regions.
Claim 10
Dependent Claim
15 words
A method according to claim 1 wherein said oxidizing step uses oxygen, without any hydrogen.
Claim 11
Dependent Claim
24 words
A method according to claim 1 wherein said oxidizing step grows said oxide regions using a temperature that is less than 1100 degrees F.
Claim 12
Dependent Claim
23 words
A method according to claim 1 further including the step of cleaning said masked surface with hydrogen prior to said step of oxidizing.
Claim 13
Dependent Claim
27 words
A method according to claim 1 wherein said protective layer is comprised of polysilicon and a buffer layer is disposed between said protective layer and said substrate.
Claim 14
Dependent Claim
12 words
A method according to claim 1 wherein said protective layer is oxynitride.
Claim 15
Dependent Claim
16 words
A method according to claim 1 wherein said substrate is not subjected to a plasma etch.
Claim 16
Dependent Claim
30 words
A method according to claim 1 further comprising the step of forming a trench in said substrate at locations corresponding to said unmasked portions prior to said step of oxidizing.
Claim 17
Dependent Claim
17 words
A method according to claim 15 wherein sidewalls of said trench are protected using nitride protective layer.
Claim 18
Dependent Claim
25 words
A method according to claim 1 wherein said oxide regions grows over said unmasked portions, but no substantial oxide growth occurs over said masked surface.
Claim 19
Dependent Claim
24 words
A method according to claim 1 wherein a top surface of said isolation regions substantially corresponds to a top surface of said protective layer.
Claim 20
Independent Claim
117 words
A method of forming an oxidation layer in a substrate comprising the steps of: applying a protective layer as a mask to portions of a top surface of said substrate where oxidation is to be prevented to obtain a masked surface having unmasked portions, said protective layer being capable of withstanding a chemical mechanical polishing and inhibiting oxide growth over a top surface of said protective layer; oxidizing said masked surface so that oxide regions are created within said substrate at locations corresponding to said unmasked portions; and removing a top portion of said oxide regions using a chemical-mechanical polishing operation and a pad to obtain isolation regions, wherein pad support is provided by said protective layer.
Claim 21
Independent Claim
117 words
A method of forming an oxidation layer in a substrate comprising the steps of: applying a protective layer as a mask to portions of a top surface of said substrate where oxidation is to be prevented to obtain a masked surface having unmasked portions, said protective layer being capable of withstanding a chemical mechanical polishing and inhibiting oxide growth over a top surface of said protective layer; oxidizing said masked surface so that oxide regions are created within said substrate at locations corresponding to said unmasked portions; and removing a top portion of said oxide regions using a chemical-mechanical polishing operation and a pad to obtain isolation regions, wherein pad support is provided by said protective layer.
Claim 22
Dependent Claim
27 words
A method according to claim 19 wherein said step of oxidizing uses a high pressure oxidation process in which said oxidation pressure is greater than 2 atmospheres.
Claim 23
Dependent Claim
24 words
A method according to claim 20 wherein said oxidizing step grows said oxide regions using a temperature that is less than 1100 degrees F.
Claim 24
Dependent Claim
15 words
A method according to claim 19 wherein said oxidizing step uses oxygen, without any hydrogen.
Claim 25
Dependent Claim
24 words
A method according to claim 19 wherein said oxidizing step grows said oxide regions using a temperature that is less than 1100 degrees F.
Claim 26
Dependent Claim
23 words
A method according to claim 19 further including the step of cleaning said masked surface with hydrogen prior to said step of oxidizing.
Claim 27
Dependent Claim
17 words
A method according to claim 19 wherein said oxidizing step takes 2 to 600 minutes to complete.
Claim 28
Dependent Claim
17 words
A method according to claim 19 wherein said oxidizing step takes 20 to 60 minutes to complete.
Claim 29
Dependent Claim
16 words
A method according to claim 19 wherein said substrate is not subjected to a plasma etch.
Claim 30
Dependent Claim
24 words
A method according to claim 19 wherein a top surface of said isolation regions substantially corresponds to a top surface of said protective layer.
Claim 31
Dependent Claim
30 words
A method according to claim 19 further comprising the step of forming a trench in said substrate at locations corresponding to said unmasked portions prior to said step of oxidizing.
Claim 32
Dependent Claim
18 words
A method according to claim 29 wherein sidewalls of said trench are protected using a nitride protective layer.
Claim 33
Dependent Claim
27 words
A method according to claim 29 wherein said step of oxidizing uses a high pressure oxidation process in which said oxidation pressure is greater than 2 atmospheres.
Claim 34
Dependent Claim
24 words
A method according to claim 31 wherein said oxidizing step grows said oxide regions using a temperature that is less than 1100 degrees F.
Claim 35
Dependent Claim
15 words
A method according to claim 29 wherein said oxidizing step uses oxygen, without any hydrogen.
Claim 36
Dependent Claim
24 words
A method according to claim 29 wherein said oxidizing step grows said oxide regions using a temperature that is less than 1100 degrees F.
Claim 37
Dependent Claim
23 words
A method according to claim 29 further including the step of cleaning said masked surface with hydrogen prior to said step of oxidizing.
Claim 38
Dependent Claim
32 words
A method according to claim 19 wherein said protective layer is comprised of silicon nitride, said substrate is silicon, and a buffer layer is disposed between said protective layer and said substrate.
Claim 39
Dependent Claim
27 words
A method according to claim 19 wherein said protective layer is comprised of polysilicon and a buffer layer is disposed between said protective layer and said substrate.
Claim 40
Dependent Claim
12 words
A method according to claim 19 wherein said protective layer is oxynitride.
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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) | 2003-06-06 | 2003-12-06 | 2004-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-06-06 | 2007-12-06 | 2008-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-06-06 | 2011-12-06 | 2012-06-06 | $7700.00 | Window Closed / Lapsed |