Patent US5880006A successfully refreshed from Google Patents.
US5880006A
Expired / Lapsed
US
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Method for fabrication of a semiconductor device
Assignee: Philips Semiconductors Inc
•
Filing: 1998-05-22
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Granted: 1999-03-09
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Expires: 2018-05-22
Abstract
Abstract A method for forming a semiconductor structure on an active area mesa with minimal loss of field oxide deposited in isolation trenches adjacent the mesa. The trench insulating material is protected by an etch barrier layer having at least a partial resistance to etchants used in further device processing steps. The barrier layer may also be deposited over the surface of the substrate to protect it from damage during device processing. The barrier layer may be removed by an etchant having a selectivity for the barrier layer over that of the surrounding device elements. Final processing of the device may be completed once the barrier layer is removed.
Inventors
- 👤 Xi-Wei Lin
- 👤 Henry Lee
- 👤 Ian R. Harvey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:14
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
113 words
A method for forming a semiconductor structure, comprising: defining isolation trenches in a semiconductor substrate to define at least one active area mesa; filling the trenches with an insulating material; forming a gate electrode on said active area mesa; depositing an etch barrier of silicon nitride layer over the insulating material; depositing a spacer material; etching the spacer material with a first etchant having a selectivity for etching the spacer material at a higher rate than the etch barrier layer, thereby forming spacers adjacent the gate electrode; and etching the etch barrier layer with a second etchant having a selectivity for etching the etch barrier layer at a greater rate than the spacers.
Claim 2
Independent Claim
113 words
A method for forming a semiconductor structure, comprising: defining isolation trenches in a semiconductor substrate to define at least one active area mesa; filling the trenches with an insulating material; forming a gate electrode on said active area mesa; depositing an etch barrier of silicon nitride layer over the insulating material; depositing a spacer material; etching the spacer material with a first etchant having a selectivity for etching the spacer material at a higher rate than the etch barrier layer, thereby forming spacers adjacent the gate electrode; and etching the etch barrier layer with a second etchant having a selectivity for etching the etch barrier layer at a greater rate than the spacers.
Claim 3
Dependent Claim
20 words
The method of claim 1, wherein the first etchant is a plasma mixture including CHF 3 and CF 4 gas.
Claim 4
Dependent Claim
21 words
The method of claim 1, further including the step of growing an oxide layer prior to depositing the etch barrier layer.
Claim 5
Dependent Claim
20 words
The method of claim 3, wherein the etch barrier layer is deposited to a thickness of at least 100 Angstroms.
Claim 6
Dependent Claim
16 words
The method of claim 1, further including planarizing the insulating material prior to forming gate electrode.
Claim 7
Dependent Claim
25 words
The method of claim 3, further including etching the exposed oxide layer after etching of said etch barrier layer to expose the underlying substrate surface.
Claim 8
Dependent Claim
17 words
The method of claim 1, wherein said second etchant is a mixture of phosphoric acid and water.
Claim 9
Dependent Claim
36 words
The method of claim 1, wherein said etch barrier layer is silicon nitride deposited to a thickness of approximately 100 Angstrom and said first etchant is a plasma mixture of CHF 3 and CF 4 gas.
Claim 10
Dependent Claim
16 words
The method of claim 8, wherein said second etchant is the first etchant with additional oxygen.
Claim 11
Independent Claim
120 words
A method of forming a semiconductor structure, comprising: etching a semiconductor substrate to form trenches defining an active area mesa; depositing an insulating material in the trenches; forming a gate electrode on the mesa; depositing a silicon nitride layer over at least a portion of the silicon substrate, the silicon nitride layer covering at least the insulating material; depositing an oxide layer; etching the oxide layer with a first etchant to form spacers adjacent the gate electrode, the first etchant having a selectivity for etching the oxide layer at a faster rate than the silicon nitride layer; and etching the nitride layer with a second etchant having a selectivity for etching silicon nitride at a faster rate than silicon oxide.
Claim 12
Independent Claim
120 words
A method of forming a semiconductor structure, comprising: etching a semiconductor substrate to form trenches defining an active area mesa; depositing an insulating material in the trenches; forming a gate electrode on the mesa; depositing a silicon nitride layer over at least a portion of the silicon substrate, the silicon nitride layer covering at least the insulating material; depositing an oxide layer; etching the oxide layer with a first etchant to form spacers adjacent the gate electrode, the first etchant having a selectivity for etching the oxide layer at a faster rate than the silicon nitride layer; and etching the nitride layer with a second etchant having a selectivity for etching silicon nitride at a faster rate than silicon oxide.
Claim 13
Dependent Claim
19 words
The method of claim 10, further including forming a second oxide layer prior to depositing the silicon nitride layer.
Claim 14
Dependent Claim
20 words
The method of claim 10, wherein the first etchant is a plasma mixture of CHF 3 and CE 4 gas.
Claim 15
Dependent Claim
20 words
The method of claim 10 wherein the second etchant is a plasma mixture of CF 4 /CHF 3 and oxygen.
Claim 16
Dependent Claim
15 words
The method of claim 10, wherein the silicon nitride layer is approximately 100 Angstroms thick.
Claim 17
Dependent Claim
18 words
The method of claim 10, wherein etching the silicon nitride is performed using the spacers as a mask.
Claim 18
Dependent Claim
18 words
The method of claim 10, further including growing an oxide layer prior to depositing the silicon nitride layer.
Claim 19
Dependent Claim
22 words
The method of claim 16, further including the step of etching the second oxide layer after etching of the silicon nitride layer.
Claim 20
Dependent Claim
22 words
The method of claim 10, wherein the first etchant has a selectivity for etching the oxide of at least 4 to 1.
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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) | 2002-03-08 | 2002-09-07 | 2003-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-03-08 | 2006-09-07 | 2007-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-03-08 | 2010-09-07 | 2011-03-09 | $7700.00 | Window Closed / Lapsed |