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US5733813A
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Method for forming planarized field isolation regions
Assignee: National Semiconductor Corp
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Filing: 1996-05-09
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Granted: 1998-03-31
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Expires: 2016-05-09
Abstract
Abstract Planarized field isolation regions are formed in a semiconductor substrate to isolate adjacent semiconductor devices by implanting an isolation material, such as oxygen or nitrogen ions, into a substrate patterned to define the field isolation regions. The implanted isolation material combines with the silicon in the substrate to form a field isolation region that extends downward from the surface of the substrate.
Inventors
- 👤 Hung Sheng Chen
- 👤 Chih Sieh Teng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:26
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/0125; H10W10/10; H10W10/13
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
104 words
A method for forming field isolation regions in a silicon substrate, the method comprising the steps of: forming a masking layer on the substrate; patterning and etching the masking layer to expose a surface region of the substrate; implanting the surface region of the substrate with a material to form an implant region that extends downward from the top surface of the substrate; and annealing the substrate in an ambient having substantially no oxygen so that the material in the implanted region chemically reacts with the silicon substrate to form a field isolation region that extends downward from the top surface of the substrate.
Claim 2
Independent Claim
104 words
A method for forming field isolation regions in a silicon substrate, the method comprising the steps of: forming a masking layer on the substrate; patterning and etching the masking layer to expose a surface region of the substrate; implanting the surface region of the substrate with a material to form an implant region that extends downward from the top surface of the substrate; and annealing the substrate in an ambient having substantially no oxygen so that the material in the implanted region chemically reacts with the silicon substrate to form a field isolation region that extends downward from the top surface of the substrate.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the masking layer includes a layer of oxide and an overlying layer of silicon nitride.
Claim 4
Dependent Claim
11 words
The method of claim 1 wherein the material includes oxygen ions.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein the material is implanted in multiple steps prior to the annealing step.
Claim 6
Dependent Claim
11 words
The method of claim 1 wherein the material includes nitrogen ions.
Claim 7
Dependent Claim
20 words
The method of claim 1 and further comprising the step of removing the masking layer prior to the annealing step.
Claim 8
Dependent Claim
10 words
The method of claim 1 wherein the ambient includes nitrogen.
Claim 9
Dependent Claim
19 words
The method of claim 5 wherein the nitrogen ions are implanted in multiple steps prior to the annealing step.
Claim 10
Dependent Claim
26 words
The method of claim 1 and further comprising the step of forming a layer of screen oxide over the surface region prior to the implanting step.
Claim 11
Dependent Claim
21 words
The method of claim 9 and further comprising the step of removing the layer of screen oxide after the annealing step.
References Cited (Backward Citations)
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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) | 2001-03-30 | 2001-09-29 | 2002-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-03-30 | 2005-09-29 | 2006-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-03-30 | 2009-09-29 | 2010-03-31 | $7700.00 | Window Closed / Lapsed |