US5065217A
Expired / Lapsed
US
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Process for simultaneously fabricating isolation structures for bipolar and CMOS circuits
Assignee: Texas Instruments Inc
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Filing: 1990-12-18
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Granted: 1991-11-12
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Expires: 2010-12-18
Abstract
Abstract An isolation structure for bipolar and CMOS circuits formed during the same processing steps to optimize the integration of bipolar and CMOS circuits. A deep trench (46) is formed in a semiconductor circuit for providing deep isolation for bipolar circuits. A shallow recess (56) is then formed simultaneous with a stepped sidewall structure of the deep trench. The recess (56) and the trench (46) are covered by an insulating oxide (60). and thereafter filled with an undoped polysilicon (62) to form the different isolating structures for the different types of circuits.
Inventors
- 👤 Douglas P. Verret
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:09
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/041; H10W10/40
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
33 words
An isolating structure for MOS circuits, comprising: a shallow recess formed in a semiconductor substrate; a thin insulator formed on the surfaces of said recess; and a polysilicon dielectric filling the shallow recess.
Claim 2
Dependent Claim
33 words
An isolating structure for MOS circuits, comprising: a shallow recess formed in a semiconductor substrate; a thin insulator formed on the surfaces of said recess; and a polysilicon dielectric filling the shallow recess.
Claim 3
Dependent Claim
15 words
The isolation structure of claim 1, wherein said shallow recess is approximately 0.8 microns deep.
Claim 4
Dependent Claim
14 words
The isolation structure of claim 1, wherein said thin insulator is an oxide layer.
Claim 5
Dependent Claim
37 words
The semiconductor substrate of claim 1, further comprising: an NMOS transistor formed in said semiconductor substrate; and a PMOS transistor formed in said semiconductor substrate, said PMOS transistor isolated by said isolating structure from the NMOS transistor.
Claim 6
Dependent Claim
24 words
The isolating structure of claim 1, wherein said shallow recess has substantially vertical sidewalls so as to reduce lateral extensions of said isolating structure.
Claim 7
Dependent Claim
19 words
The isolating structure of claim 1, wherein said deep trench is formed to a depth of approximately 8 microns.
Claim 8
Dependent Claim
46 words
An isolating structure for MOS and bipolar circuits, comprising: a shallow recess and a deep trench formed in a semiconductor substrate; a thin insulation layer formed on the surface of said recess and said deep trench; and polysilicon material filling said recess and said deep trench.
Claim 9
Dependent Claim
46 words
An isolating structure for MOS and bipolar circuits, comprising: a shallow recess and a deep trench formed in a semiconductor substrate; a thin insulation layer formed on the surface of said recess and said deep trench; and polysilicon material filling said recess and said deep trench.
Claim 10
Dependent Claim
80 words
An isolating structure for MOS and bipolar circuits, comprising: a semiconductor substrate; a layer of silicon oxide formed on the semiconductor substrate; a layer of non-oxidizing dielectric material formed over said silicon oxide; a deep trench formed through said silicon oxide layer and said dielectric material into said semiconductor substrate; a shallow recess formed through said layer of silicon oxide and said dielectric material extending into said semiconductor substrate; and a non-conductive material filling said deep trench and said recess.
Claim 11
Dependent Claim
80 words
An isolating structure for MOS and bipolar circuits, comprising: a semiconductor substrate; a layer of silicon oxide formed on the semiconductor substrate; a layer of non-oxidizing dielectric material formed over said silicon oxide; a deep trench formed through said silicon oxide layer and said dielectric material into said semiconductor substrate; a shallow recess formed through said layer of silicon oxide and said dielectric material extending into said semiconductor substrate; and a non-conductive material filling said deep trench and said recess.
Claim 12
Dependent Claim
49 words
An isolation structure for use in a semiconductor substrate, comprising: a shallow recess formed in said semiconductor substrate; a deep trench formed in said semiconductor substrate; a thin insulator formed on the surfaces of said recess and said trench; and a polysilicon dielectric filling said recess and said trench.
Claim 13
Dependent Claim
49 words
An isolation structure for use in a semiconductor substrate, comprising: a shallow recess formed in said semiconductor substrate; a deep trench formed in said semiconductor substrate; a thin insulator formed on the surfaces of said recess and said trench; and a polysilicon dielectric filling said recess and said trench.
Claim 14
Dependent Claim
27 words
The isolation structure of claim 9, wherein said shallow recess includes substantially vertical sidewalls to reduce a lateral surface area of said substrate required by said structure.
Claim 15
Dependent Claim
24 words
The isolation structure of claim 9, wherein said shallow recess is about 0.8 micron deep, and said trench is greater than five microns deep.
Claim 16
Dependent Claim
32 words
The isolation structure of claim 9, wherein said trench includes stepped sidewalls such that an upper portion of said trench has a greater lateral area than a lower portion of said trench.
Claim 17
Dependent Claim
25 words
The isolation structure of claim 12, wherein said upper trench portion has a lateral area substantially the same as a lateral area of said recess.
Claim 18
Dependent Claim
18 words
The isolation structure of claim 9, further including a conductor formed over one said trench or recess structure.
Claim 19
Dependent Claim
37 words
An isolating structure for circuits formed in a semiconductor substrate, comprising: a shallow recess formed in the semiconductor substrate; a thin insulator formed on the surfaces of said recess; and a polysilicon dielectric filling the shallow recess.
Claim 20
Dependent Claim
37 words
An isolating structure for circuits formed in a semiconductor substrate, comprising: a shallow recess formed in the semiconductor substrate; a thin insulator formed on the surfaces of said recess; and a polysilicon dielectric filling the shallow recess.
Claim 21
Dependent Claim
15 words
The isolation structure of claim 15, wherein said shallow recess is approximately 0.8 microns deep.
Claim 22
Dependent Claim
13 words
The isolation structure of claim 15, wherein said insulator is an oxide layer.
Claim 23
Dependent Claim
24 words
The isolating structure of claim 15, wherein said shallow recess has substantially vertical sidewalls so as to reduce lateral extensions of said isolating structure.
Claim 24
Dependent Claim
48 words
An isolating structure for circuits formed in a semiconductor substrate, comprising: a shallow recess and a deep trench formed in a semiconductor substrate; a thin insulation layer formed on the surface of said recess and said deep trench; and polysilicon material filling said recess and said deep trench.
Claim 25
Dependent Claim
48 words
An isolating structure for circuits formed in a semiconductor substrate, comprising: a shallow recess and a deep trench formed in a semiconductor substrate; a thin insulation layer formed on the surface of said recess and said deep trench; and polysilicon material filling said recess and said deep trench.
Claim 26
Dependent Claim
79 words
An isolating structure for circuits formed in a semiconductor substrate, comprising: a layer of silicon oxide formed on the semiconductor substrate; a layer of non-oxidizing dielectric material formed over said silicon oxide; a deep trench formed through said silicon oxide layer and said dielectric material into said semiconductor substrate; a shallow recess formed through said layer of silicon oxide and said dielectric material extending into said semiconductor substrate; and a non-conductive material filling said deep trench and said recess.
Claim 27
Dependent Claim
79 words
An isolating structure for circuits formed in a semiconductor substrate, comprising: a layer of silicon oxide formed on the semiconductor substrate; a layer of non-oxidizing dielectric material formed over said silicon oxide; a deep trench formed through said silicon oxide layer and said dielectric material into said semiconductor substrate; a shallow recess formed through said layer of silicon oxide and said dielectric material extending into said semiconductor substrate; and a non-conductive material filling said deep trench and said recess.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-11-11 | 1995-05-13 | 1995-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-11 | 1999-05-13 | 1999-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-11 | 2003-05-13 | 2003-11-12 | $7700.00 | Window Closed / Lapsed |