US5616513A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shallow trench isolation with self aligned PSG layer
Assignee: International Business Machines Corp
•
Filing: 1995-06-01
•
Granted: 1997-04-01
•
Expires: 2015-06-01
Abstract
Abstract A method for forming trench isolation and in specific shallow trench isolation(STI) using SiO 2 plugs is proposed. The SiO 2 plugs of the STI have a buried phosphorus (P) rich layer introduced during and subsequent to the trench formation to tie up any sodium ionic contamination from processes prior to gate formation. P impurity layer is formed below the surface of the deposited SiO 2 layer. A preferred method for forming the buried P layer is by shallow implantation in a vertical direction into the deposited SiO 2 layer prior to planarization. The process is self aligned to the trench isolation regions.
Inventors
- 👤 Joseph F. Shepard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:00
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/0148; H10W10/10; H10W10/17
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
111 words
A method of forming a trench isolation in a silicon substrate having a frontside and a backside, said trench isolation consisting of plurality of trenches with silicon dioxide plugs, comprising the steps of: etching said plurality of trenches on the frontside in said silicon substrate; depositing a layer of silicon dioxide in contact with said frontside and to fill said plurality of trenches; forming a layer of phosphorus impurities beneath the surface of said silicon dioxide layer; and, removing the silicon dioxide layer, from the frontside of the silicon substrate, outside of said plurality of trenches, thereby forming said trenches with silicon dioxide plugs containing a buried layer of phosphorus impurities.
Claim 2
Independent Claim
111 words
A method of forming a trench isolation in a silicon substrate having a frontside and a backside, said trench isolation consisting of plurality of trenches with silicon dioxide plugs, comprising the steps of: etching said plurality of trenches on the frontside in said silicon substrate; depositing a layer of silicon dioxide in contact with said frontside and to fill said plurality of trenches; forming a layer of phosphorus impurities beneath the surface of said silicon dioxide layer; and, removing the silicon dioxide layer, from the frontside of the silicon substrate, outside of said plurality of trenches, thereby forming said trenches with silicon dioxide plugs containing a buried layer of phosphorus impurities.
Claim 3
Dependent Claim
33 words
A method of claim 1, wherein said forming a layer of phosphorus impurities is carried out after deposition of partial thickness of said silicon dioxide layer to partially fill said plurality of trenches.
Claim 4
Dependent Claim
14 words
A method of claim 1, wherein said layer of phosphorus impurities formed by implantation.
Claim 5
Dependent Claim
19 words
A method of claim 3 wherein said implanted dose of said P impurities is selected from 1E15/cm2 to 5E15/cm2.
Claim 6
Independent Claim
128 words
A method of forming a trench isolation in a silicon substrate having a frontside and a backside, said trench isolation consisting of plurality of trenches with silicon dioxide plugs, comprising the steps of: etching said plurality of trenches on said frontside in said silicon substrate; depositing a first layer of silicon dioxide so as to partially fill said plurality of trenches; forming a layer of phosphorus impurities beneath surface of said first layer of silicon dioxide; depositing a second layer of silicon dioxide so as to completely fill said plurality of trenches; and, removing said first and second silicon dioxide layer from the frontside of the silicon substrate, outside said plurality of trenches, thereby forming said trenches with silicon dioxide plugs containing a buried layer of phosphorus impurities.
Claim 7
Independent Claim
128 words
A method of forming a trench isolation in a silicon substrate having a frontside and a backside, said trench isolation consisting of plurality of trenches with silicon dioxide plugs, comprising the steps of: etching said plurality of trenches on said frontside in said silicon substrate; depositing a first layer of silicon dioxide so as to partially fill said plurality of trenches; forming a layer of phosphorus impurities beneath surface of said first layer of silicon dioxide; depositing a second layer of silicon dioxide so as to completely fill said plurality of trenches; and, removing said first and second silicon dioxide layer from the frontside of the silicon substrate, outside said plurality of trenches, thereby forming said trenches with silicon dioxide plugs containing a buried layer of phosphorus impurities.
Claim 8
Dependent Claim
14 words
A method of claim 5, wherein said layer of phosphorus impurities formed by implantation.
Claim 9
Dependent Claim
19 words
A method of claim 5 wherein said implanted dose of said P impurities is selected from 1E15/cm2 to 5E15/cm2.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-03-31 | 2000-09-30 | 2001-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-03-31 | 2004-09-30 | 2005-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-03-31 | 2008-09-30 | 2009-04-01 | $7700.00 | Window Closed / Lapsed |