US4825277A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Trench isolation process and structure
Assignee: NXP USA Inc
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Filing: 1987-11-17
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Granted: 1989-04-25
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Expires: 2007-11-17
Abstract
Abstract A structure and method for forming an isolation wall in an etched trench are described. The trench walls are covered by a thin silicon oxide layer and the trench conformally filled with an oxy-nitride mixture having a particular range of composition so as to produce a neutral to slight tensile stress in the oxy-nitride relative to silicon. The structure is very simple to fabricate and creates fewer defects in the silicon substrate than prior art techniques. Buried voids in the filled trench are eliminated.
Inventors
- 👤 Robert Mattox
- 👤 Steven Fong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:26
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/10; H10W10/17
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
56 words
A semiconductor device comprising: a semiconductor substrate having a major surface; a trench extending into said substrate from said major surface wherein said trench has a sidewall and a bottom; a silicon oxide-silicon nitride mixture substantially filling said trench to a first surface below said major surface; and a silicon nitride layer completely covering said mixture.
Claim 2
Dependent Claim
56 words
A semiconductor device comprising: a semiconductor substrate having a major surface; a trench extending into said substrate from said major surface wherein said trench has a sidewall and a bottom; a silicon oxide-silicon nitride mixture substantially filling said trench to a first surface below said major surface; and a silicon nitride layer completely covering said mixture.
Claim 3
Dependent Claim
46 words
The device of claim 1 wherein said substrate comprises a semiconductor body having a surface dielectric layer thereon extending to said major surface and wherein said trench extends into said body and further comprising a silicon oxide lining covering at least said sidewall of said trench.
Claim 4
Dependent Claim
17 words
The device of claim 1 further comprising a silicon nitride filled region centrally located in said mixture.
Claim 5
Dependent Claim
29 words
The device of claim 1 wherein said silicon oxide-silicon nitride mixture comprises a silicon oxy-nitride having an equivalent mole fraction of silicon nitride in the range 0.1-0.5 silicon nitride.
Claim 6
Dependent Claim
20 words
The device of claim 4 wherein said equivalent mole fraction of silicon nitride is in the range 0.1-0.4 silicon nitride.
Claim 7
Dependent Claim
20 words
The device of claim 5 wherein said equivalent mole fraction of silicon nitride is in the range 0.1-0.3 silicon nitride.
Claim 8
Dependent Claim
20 words
The device of claim 6 wherein said equivalent mole fraction of silicon nitride is in the range 0.1-0.20 silicon nitride.
Claim 9
Dependent Claim
17 words
The device of claim 1 wherein said silicon oxide-silicon nitride mixture exhibits tensile stress relative to silicon.
Claim 10
Dependent Claim
17 words
The device of claim 8 wherein said tensile stress is less than 5×10 9 dynes/cm 2 .
Claim 11
Dependent Claim
20 words
The device of claim 1 wherein said silicon oxide-silicon nitride mixture has a refractive index in the range about 1.5-1.8.
Claim 12
Dependent Claim
37 words
A semiconductor device comprising: a substrate comprising a semiconductor body; a trench extending into said body; a silicon oxy-nitride mixture in said trench; and a silicon nitride layer completely covering said silicon oxy-nitride mixture in said trench.
Claim 13
Dependent Claim
37 words
A semiconductor device comprising: a substrate comprising a semiconductor body; a trench extending into said body; a silicon oxy-nitride mixture in said trench; and a silicon nitride layer completely covering said silicon oxy-nitride mixture in said trench.
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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) | 1992-04-24 | 1992-10-24 | 1993-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-24 | 1996-10-24 | 1997-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-24 | 2000-10-24 | 2001-04-25 | $7700.00 | Window Closed / Lapsed |