US6489215B2
Expired / Lapsed
US
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Method of making insulator for electrical structures
Assignee: Micron Technology Inc
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Filing: 2001-02-16
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Granted: 2002-12-03
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Expires: 2021-02-16
Abstract
Abstract Structures and methods are disclosed for insulating a polysilicon gate adjacent to an electrically active region with a silicon base layer. A layer of silicon nitride having a thickness in a range from about 100 Å to about 150 Å is conformally deposited over the polysilicon gate. A layer of silicon dioxide is formed over the layer of silicon nitride on the polysilicon gate. The layer of silicon dioxide is subjected to a spacer etch to form spacers upon the layer of silicon nitride and on lateral sidewalls of the polysilicon gate. A portion of the layer of silicon nitride situated between the polysilicon gate and the spacer is removed by an etching process that is selective to silicon dioxide and to polysilicon. The etch forms a recess defined between the polysilicon gate, and each respective spacer. A cover layer is formed to close an opening to the recess so as to enclose a void therein. Alternatively, the etch can be a series of selective etches that extends the recess into the silicon base layer, after which the silicon base layer is implanted so that the recess isolates electrically active areas in the silicon base layer. A void is then enclosed below the opening to the recess within the silicon base layer by a cover layer deposited non-conformally thereover.
Inventors
- 👤 Chandra V. Mouli
- 👤 Fernando Gonzalez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:08
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/015; H10D64/60; H10D64/66; H10D64/671; H10D64/675; H10D64/679; H10D8/00; H10D8/01; H10D8/045; H10W; H10W10/00; H10W10/01; H10W10/021; H10W10/20
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
127 words
A void formation method comprising: providing a structure projecting from a semiconductor substrate, said structure having a base at said semiconductor substrate and an opposite projecting end such that a lateral surface of said structure extends from said base to said opposite projecting end, wherein: said lateral surface is next to an adjacent inner layer of primary material; said inner layer is next to an outer layer of secondary material so that said inner layer is located between said lateral surface and said outer layer; and said primary material can be selectively removed over said secondary material; selectively removing some of the primary material to form a plurality of voids; and capping said voids to form a plurality of closed voids on each side of the structure.
Claim 2
Dependent Claim
127 words
A void formation method comprising: providing a structure projecting from a semiconductor substrate, said structure having a base at said semiconductor substrate and an opposite projecting end such that a lateral surface of said structure extends from said base to said opposite projecting end, wherein: said lateral surface is next to an adjacent inner layer of primary material; said inner layer is next to an outer layer of secondary material so that said inner layer is located between said lateral surface and said outer layer; and said primary material can be selectively removed over said secondary material; selectively removing some of the primary material to form a plurality of voids; and capping said voids to form a plurality of closed voids on each side of the structure.
Claim 3
Dependent Claim
27 words
The method as recited in claim 1 , wherein selectively removing some of the primary material comprises removing a portion of said outer layer of secondary material.
Claim 4
Dependent Claim
61 words
The method as recited in claim 2 , wherein: removing said portion of said outer layer of secondary material comprises a spacer etch of said outer layer of secondary material to form, adjacent to said lateral surface, a spacer upon the inner layer of primary material; and each said capped void is situated between one of said spacers and the structure.
Claim 5
Dependent Claim
24 words
The method as recited in claim 1 , wherein: capping said voids comprises depositing a cover layer over said voids without filling said voids.
Claim 6
Dependent Claim
29 words
The method as recited in claim 1 , wherein said outer layer of secondary material comprises material selected from the group consisting of silicon dioxide, polysilicon, and silicon nitride.
Claim 7
Dependent Claim
36 words
The method as recited in claim 1 , wherein said structure comprises a gate layer projecting from a gate oxide layer, said gate oxide layer being adjacent to an electrically active area within said semiconductor substrate.
Claim 8
Dependent Claim
44 words
The method as recited in claim 1 , wherein: said inner layer of primary material is substantially composed of one of silicon dioxide and silicon nitride; and said outer layer of secondary material is composed of the other of silicon dioxide and silicon nitride.
Claim 9
Dependent Claim
29 words
The method as recited in claim 1 , wherein said inner layer of primary material has a thickness in the range from about 100 Å to about 150 Å.
Claim 10
Dependent Claim
32 words
The method as recited in claim 4 , wherein: said cover layer is composed of a dielectric material; and said outer layer of secondary material is composed of an electrically conductive material.
Claim 11
Dependent Claim
44 words
The method as recited in claim 1 , wherein selectively removing some of the primary material comprises etching a portion of said inner layer of primary material with an etch that is selective to said structure and to said outer layer of secondary material.
Claim 12
Dependent Claim
14 words
The method as, recited in claim 10 , wherein said etch is dry etch.
Claim 13
Dependent Claim
15 words
The method as recited in claim 10 , wherein said etch is a wet etch.
Claim 14
Dependent Claim
29 words
The method as recited in claim 4 , wherein said cover layer is composed of a material selected from the group consisting of silicon nitride, silicon dioxide, and polysilicon.
Claim 15
Dependent Claim
33 words
The method as recited in claim 4 , wherein said cover layer is composed of an electrically conductive material and said outer layer of secondary material is substantially composed of a dielectric material.
Claim 16
Dependent Claim
104 words
The method as recited in claim 1 , wherein: selectively removing some of the primary material comprises: performing a spacer etch of said outer layer of secondary material to form a pair of spacers upon the inner layer of primary material, each said spacer being adjacent said lateral surface; and etching a portion of said inner layer of primary material with an etch that is selective to said structure and to said outer layer of secondary material to form an opening to a recess that is remote from said semiconductor substrate with an etchant that is selective to said structure and to said spacer.
Claim 17
Dependent Claim
205 words
The method as recited in claim 1 , wherein: selectively removing some of the primary material comprises: performing a spacer etch of said outer layer of secondary material to form a pair of spacers upon the inner layer of primary material, each said spacer being adjacent said lateral surface; etching a portion of said inner layer of primary material with an etch that is selective to said structure and said outer layer of secondary material to form adjacent said lateral surface: a top portion of the inner layer of primary material that is remote from the semiconductor substrate; a bottom portion of the inner layer of primary material that is proximal to the semiconductor substrate; a first recess defined in part by the structure and the top portion of the inner layer of primary material, the first recess having an opening remote from the semiconductor substrate; and a second recess defined in part by the structure and the bottom portion of the inner layer of primary material, the second recess having an opening proximal to the semiconductor substrate; and capping said voids comprises depositing a cover layer over the opening to the first recess and the opening to the second recess on the lateral surface.
Claim 18
Independent Claim
173 words
A method for insulating a gate comprising: providing a gate stack projecting from a gate oxide layer upon a semiconductor substrate, said gate stack having first and second opposing lateral sides and a top surface, wherein: each said lateral side is next to an adjacent inner layer of primary material; said inner layer is next to an outer layer of secondary material so that said inner layer is located between each said lateral side and said outer layer; said primary material can be selectively removed over said secondary material; and a first spacer and a second spacer are secured to the gate stack; and forming a cover layer extending continuously upon and over the gate stack, the first spacer, the second spacer, and the gate oxide layer to form, adjacent to each of the first and second lateral sides of the gate stack, a plurality of closed voids each filled with an ambient gas and situated between the inner layer of primary material, the outer layer of secondary material, and the gate stack.
Claim 19
Independent Claim
173 words
A method for insulating a gate comprising: providing a gate stack projecting from a gate oxide layer upon a semiconductor substrate, said gate stack having first and second opposing lateral sides and a top surface, wherein: each said lateral side is next to an adjacent inner layer of primary material; said inner layer is next to an outer layer of secondary material so that said inner layer is located between each said lateral side and said outer layer; said primary material can be selectively removed over said secondary material; and a first spacer and a second spacer are secured to the gate stack; and forming a cover layer extending continuously upon and over the gate stack, the first spacer, the second spacer, and the gate oxide layer to form, adjacent to each of the first and second lateral sides of the gate stack, a plurality of closed voids each filled with an ambient gas and situated between the inner layer of primary material, the outer layer of secondary material, and the gate stack.
Claim 20
Dependent Claim
14 words
The method as recited in claim 17 , wherein said ambient gas is air.
Claim 21
Independent Claim
144 words
A method for forming an insulated structure comprising: providing a structure projecting from a semiconductor substrate, said structure having opposing first and second lateral sides, wherein: each said lateral side is next to an adjacent inner layer of primary material; said inner layer is next to an outer layer of secondary material so that said inner layer is located between each said lateral side and said outer layer; and a recess is located between the outer layer of secondary material and each of the opposing first and second lateral sides, each said recess having an opening remote from said semiconductor substrate; and forming a closing layer extending continuously upon and over said opening of each said recess to form, adjacent to each of the first and second lateral sides, a plurality of closed empty spaces situated between the closing layer and the semiconductor substrate.
Claim 22
Independent Claim
144 words
A method for forming an insulated structure comprising: providing a structure projecting from a semiconductor substrate, said structure having opposing first and second lateral sides, wherein: each said lateral side is next to an adjacent inner layer of primary material; said inner layer is next to an outer layer of secondary material so that said inner layer is located between each said lateral side and said outer layer; and a recess is located between the outer layer of secondary material and each of the opposing first and second lateral sides, each said recess having an opening remote from said semiconductor substrate; and forming a closing layer extending continuously upon and over said opening of each said recess to form, adjacent to each of the first and second lateral sides, a plurality of closed empty spaces situated between the closing layer and the semiconductor substrate.
Claim 23
Independent Claim
208 words
A method for making an insulated structure comprising: forming a gate layer upon a gate oxide layer situated upon a silicon base layer, said gate layer being adjacent to an electrically active region within said silicon base layer, said gate layer having opposing first and second lateral sides, wherein: each said lateral side is next to an adjacent inner layer of primary material; said inner layer is next to an outer layer of secondary material so that said inner layer is located between each said lateral side and said outer layer; a spacer is adjacent to each of the first and second lateral sides of the gate layer and each said spacer is attached to the gate layer by the inner layer of primary material; and a recess having an opening remote from said silicon base layer is formed in a region of the inner layer of primary material situated between each of the spacers and the gate layer; and forming a cover layer extending continuously upon and over the opening to each of the recesses, wherein a plurality of closed empty spaces is situated adjacent to each of the first and second lateral sides of the gate layer between the cover layer and the silicon base layer.
Claim 24
Independent Claim
208 words
A method for making an insulated structure comprising: forming a gate layer upon a gate oxide layer situated upon a silicon base layer, said gate layer being adjacent to an electrically active region within said silicon base layer, said gate layer having opposing first and second lateral sides, wherein: each said lateral side is next to an adjacent inner layer of primary material; said inner layer is next to an outer layer of secondary material so that said inner layer is located between each said lateral side and said outer layer; a spacer is adjacent to each of the first and second lateral sides of the gate layer and each said spacer is attached to the gate layer by the inner layer of primary material; and a recess having an opening remote from said silicon base layer is formed in a region of the inner layer of primary material situated between each of the spacers and the gate layer; and forming a cover layer extending continuously upon and over the opening to each of the recesses, wherein a plurality of closed empty spaces is situated adjacent to each of the first and second lateral sides of the gate layer between the cover layer and the silicon base layer.
Claim 25
Dependent Claim
43 words
The method as recited in claim 20 , wherein: said inner layer of primary material is composed of one of silicon dioxide and silicon nitride; and said outer layer of secondary material is composed of the other of silicon dioxide and silicon nitride.
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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) | 2005-12-02 | 2006-06-03 | 2006-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-12-02 | 2010-06-03 | 2010-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-12-02 | 2014-06-03 | 2014-12-03 | $7700.00 | Window Closed / Lapsed |