US4735679A
Expired / Lapsed
US
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Method of improving silicon-on-insulator uniformity
Assignee: International Business Machines Corp
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Filing: 1987-03-30
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Granted: 1988-04-05
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Expires: 2007-03-30
Abstract
Abstract A method of improving silicon-on-insulator uniformity using polishing. A polishing stop layer of substantially uniform thickness is provided having a first side which is made coplanar with a first side of a thicker layer of semiconductor material. A polishing process is applied to a second side of the semiconductor material until a second side of the polishing stop layer is encountered, such that the substantially uniform thickness of the polishing stop layer can be used to define the semiconductor material to a layer of uniform thickness.
Inventors
- 👤 Jerome B. Lasky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 03:24
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/20; H10P; H10P52/00; H10P90/00; H10P90/19; H10P90/1904; H10P90/1906; H10P95/00; H10P95/06; H10P95/062; H10W10/01; H10W10/021; H10W10/061; H10W10/10; H10W10/181; H10P90/1914; Y; Y10; Y10S; Y10S438/00; Y10S438/959; Y10S438/97
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
89 words
A process of planarizing a layer of material, comprising the steps of: patterning said layer of material to form apertures therein; forming in each of said apertures a polishing stop layer of uniform thickness which is thinner than said layer of material; and polishing said layer of material to a point where its surfaces are substantially coplanar with the surfaces of said polishing stop layer, such that said uniform thickness of said polishing stop layer is used to define said layer of material to a layer of uniform thickness.
Claim 2
Dependent Claim
89 words
A process of planarizing a layer of material, comprising the steps of: patterning said layer of material to form apertures therein; forming in each of said apertures a polishing stop layer of uniform thickness which is thinner than said layer of material; and polishing said layer of material to a point where its surfaces are substantially coplanar with the surfaces of said polishing stop layer, such that said uniform thickness of said polishing stop layer is used to define said layer of material to a layer of uniform thickness.
Claim 3
Independent Claim
141 words
A method of improving the thickness uniformity of a layer of material, comprising the steps of: applying a first layer of material to a support structure having a substantially planar surface to be used as a reference plane; providing apertures in said first layer of material to expose portions of said reference plane; applying to said reference plane, through each of said apertures, a conformal layer of polishing stop material of uniform thickness, the thickness of said conformal layer being thinner than said first layer of material; and polishing said first layer of material in a planar mode to a point where it is substantially coplanar with the surface of said polishing stop material, such that the substantially uniform thickness of said conformal polishing stop layer is used to define said first layer of material to a layer of uniform thickness.
Claim 4
Independent Claim
141 words
A method of improving the thickness uniformity of a layer of material, comprising the steps of: applying a first layer of material to a support structure having a substantially planar surface to be used as a reference plane; providing apertures in said first layer of material to expose portions of said reference plane; applying to said reference plane, through each of said apertures, a conformal layer of polishing stop material of uniform thickness, the thickness of said conformal layer being thinner than said first layer of material; and polishing said first layer of material in a planar mode to a point where it is substantially coplanar with the surface of said polishing stop material, such that the substantially uniform thickness of said conformal polishing stop layer is used to define said first layer of material to a layer of uniform thickness.
Claim 5
Independent Claim
133 words
A method of providing a layer of semiconductor material of uniform thickness, comprising the steps of: providing a layer of semiconductor material on a substrate, said material having at least a first surface and a second surface, said second surface extending above the level of said first surface; providing a polishing stop layer of uniform thickness having a lower surface which is substantially coplanar with said first surface of said layer of semiconductor material, said polishing stop layer being thinner than said layer of semiconductor material; and polishing said second surface of said layer of semiconductor material until said upper surface of said polishing stop layer is encountered, such that the uniform thickness of said polishing stop layer is used to define said layer of semiconductor material to a layer of uniform thickness.
Claim 6
Independent Claim
133 words
A method of providing a layer of semiconductor material of uniform thickness, comprising the steps of: providing a layer of semiconductor material on a substrate, said material having at least a first surface and a second surface, said second surface extending above the level of said first surface; providing a polishing stop layer of uniform thickness having a lower surface which is substantially coplanar with said first surface of said layer of semiconductor material, said polishing stop layer being thinner than said layer of semiconductor material; and polishing said second surface of said layer of semiconductor material until said upper surface of said polishing stop layer is encountered, such that the uniform thickness of said polishing stop layer is used to define said layer of semiconductor material to a layer of uniform thickness.
Claim 7
Independent Claim
134 words
A method of providing a layer of semiconductor material of uniform thickness, comprising the steps of: providing a layer of semiconductor material on portions of a reference plane; providing a polishing stop layer of substantially uniform thickness on different portions of said reference plane such that a first surface of said layer of semiconductor material and a first surface of said polishing stop layer are substantially coplanar, said polishing stop layer being thinner than said layer of semiconductor material; and polishing a second surface of said layer of semiconductor material in a planar mode to a point where a second surface of said polishing stop layer is encountered, such that the substantially uniform thickness of said polishing stop layer is used to define said layer of semiconductor material to a layer of uniform thickness.
Claim 8
Independent Claim
134 words
A method of providing a layer of semiconductor material of uniform thickness, comprising the steps of: providing a layer of semiconductor material on portions of a reference plane; providing a polishing stop layer of substantially uniform thickness on different portions of said reference plane such that a first surface of said layer of semiconductor material and a first surface of said polishing stop layer are substantially coplanar, said polishing stop layer being thinner than said layer of semiconductor material; and polishing a second surface of said layer of semiconductor material in a planar mode to a point where a second surface of said polishing stop layer is encountered, such that the substantially uniform thickness of said polishing stop layer is used to define said layer of semiconductor material to a layer of uniform thickness.
Claim 9
Independent Claim
144 words
A method of providing a layer of semiconductor material of uniform thickness, comprising the steps of: providing a support structure having a substantially planar surface representing a reference plane; providing a layer of semiconductor material on portions of said reference plane; providing a polishing stop layer of substantially uniform thickness on different portions of said reference plane such that a first surface of said semiconductor material and a first surface of said polishing stop layer are substantially coplanar, said polish stop layer being thinner than said layer of semiconductor material; and polishing a second surface of said layer of semiconductor material in a planar mode to a point where a second surface of said polishing stop layer is encountered, such that the substantially uniform thickness of said polishing stop layer is used to define said semiconductor material to a layer of substantially uniform thickness.
Claim 10
Independent Claim
144 words
A method of providing a layer of semiconductor material of uniform thickness, comprising the steps of: providing a support structure having a substantially planar surface representing a reference plane; providing a layer of semiconductor material on portions of said reference plane; providing a polishing stop layer of substantially uniform thickness on different portions of said reference plane such that a first surface of said semiconductor material and a first surface of said polishing stop layer are substantially coplanar, said polish stop layer being thinner than said layer of semiconductor material; and polishing a second surface of said layer of semiconductor material in a planar mode to a point where a second surface of said polishing stop layer is encountered, such that the substantially uniform thickness of said polishing stop layer is used to define said semiconductor material to a layer of substantially uniform thickness.
Claim 11
Independent Claim
144 words
A method of providing a layer of semiconductor material of uniform thickness, comprising the steps of: providing a layer of semiconductor material on portions of a reference plane, leaving other portions of said reference plane exposed; applying a conformal polishing stop layer of a substantially uniform thickness to said exposed portions of said reference plane, such that a first surface of said layer of semiconductor material and a first surface of said conformal polishing stop layer are substantially coplanar, said conformal polishing stop layer being thinner than said semiconductor material; and polishing a second surface of said layer of semiconductor material in a planar mode to a point where a second surface of said conformal stop layer is encountered, such that the substantially uniform thickness of said conformal stop layer is used to define said semiconductor material to a layer of substantially uniform thickness.
Claim 12
Independent Claim
144 words
A method of providing a layer of semiconductor material of uniform thickness, comprising the steps of: providing a layer of semiconductor material on portions of a reference plane, leaving other portions of said reference plane exposed; applying a conformal polishing stop layer of a substantially uniform thickness to said exposed portions of said reference plane, such that a first surface of said layer of semiconductor material and a first surface of said conformal polishing stop layer are substantially coplanar, said conformal polishing stop layer being thinner than said semiconductor material; and polishing a second surface of said layer of semiconductor material in a planar mode to a point where a second surface of said conformal stop layer is encountered, such that the substantially uniform thickness of said conformal stop layer is used to define said semiconductor material to a layer of substantially uniform thickness.
Claim 13
Independent Claim
187 words
A method of providing a layer of semiconductor material of uniform thickness, comprising the steps of: providing a layer of semiconductor material on portions of a reference plane, leaving other portions of said reference plane exposed; applying a conformal polishing stop layer of a substantially uniform thickness upon said semiconductor material and said exposed portions of said reference plane, such that a first surface of said layer of semiconductor material and a first surface of said conformal polishing stop layer on said exposed portions of said reference plane are substantially coplanar, said conformal polishing stop layer being thinner than said semiconductor material; removing portions of said conformal polishing stop layer from a second surface of said layer of semiconductor material; and polishing said second surface of said layer of semiconductor material to a point where a second surface of said conformal polishing stop layer on said exposed portions of said reference plane is encountered, such that the substantially uniform thickness of said conformal polishing stop layer on said exposed portions of said reference plane are used to define said semiconductor material to a layer of uniform thickness.
Claim 14
Independent Claim
187 words
A method of providing a layer of semiconductor material of uniform thickness, comprising the steps of: providing a layer of semiconductor material on portions of a reference plane, leaving other portions of said reference plane exposed; applying a conformal polishing stop layer of a substantially uniform thickness upon said semiconductor material and said exposed portions of said reference plane, such that a first surface of said layer of semiconductor material and a first surface of said conformal polishing stop layer on said exposed portions of said reference plane are substantially coplanar, said conformal polishing stop layer being thinner than said semiconductor material; removing portions of said conformal polishing stop layer from a second surface of said layer of semiconductor material; and polishing said second surface of said layer of semiconductor material to a point where a second surface of said conformal polishing stop layer on said exposed portions of said reference plane is encountered, such that the substantially uniform thickness of said conformal polishing stop layer on said exposed portions of said reference plane are used to define said semiconductor material to a layer of uniform thickness.
Claim 15
Dependent Claim
34 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 7, wherein said polishing step comprises a physical abrasion process carried out in the presence of a slurry.
Claim 16
Dependent Claim
26 words
A method providing a layer of semiconductor material of uniform thickness, as claimed in claim 8, wherein said slurry has a pH of greater than 7.
Claim 17
Dependent Claim
23 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 9, wherein said slurry has silicon particulates.
Claim 18
Dependent Claim
46 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 8, wherein said semiconductor material is silicon, and wherein said polishing stop layer is composed of a material which has polishing rate which is substantially slower than that of silicon.
Claim 19
Dependent Claim
38 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 7, wherein said polishing stop layer is selected from the group consisting of tungsten, millennium, titanium, tantalum, platinum, palladium, nickel and cobalt.
Claim 20
Dependent Claim
26 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 7, wherein said polishing stop layer is made of tungsten.
Claim 21
Dependent Claim
33 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 13, wherein said polishing stop layer is subject to an annealing process prior to said polishing step.
Claim 22
Dependent Claim
29 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 7, wherein said reference plane is the surface of a silicon dioxide layer.
Claim 23
Dependent Claim
26 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 7, wherein said polishing stop layer is applied by evaporation.
Claim 24
Dependent Claim
51 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 7, comprising the step of providing an insulator film on exposed portions of said semiconductor material before said applying step, to prevent chemical reaction between said semiconductor material and material of said polishing stop layer.
Claim 25
Dependent Claim
42 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 7, wherein said portions of said polishing stop layer are removed from said second surface of said layer of semiconductor material by using a lift-off process.
Claim 26
Dependent Claim
42 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 7, wherein said layer of semiconductor material on the portions of the reference plane are provided in the form of semiconductor studs separated by isolation regions.
Claim 27
Dependent Claim
42 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 7, wherein said layer of semiconductor material on the portions of the reference plane are provided in the form of semiconductor bodies bordered by isolation regions.
Claim 28
Dependent Claim
42 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 7, wherein said layer of semiconductor material on the portions of the reference plane are provided in the form of semiconductor sheets separated by isolation regions.
Claim 29
Dependent Claim
42 words
A method of providing a layer of semiconductor material of uniform thickness, as claimed in claim 7, wherein said layer of semiconductor material on the portions of the reference plane are provided in the form of semiconductor strips separated by isolation regions.
Claim 30
Dependent Claim
24 words
A method as claimed in claim 7 further comprising the step of removing the remaining portions of said stop layer from said reference plane.
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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) | 1991-04-05 | 1991-10-05 | 1992-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-05 | 1995-10-05 | 1996-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-05 | 1999-10-05 | 2000-04-05 | $7700.00 | Window Closed / Lapsed |