Patent US5380373A successfully refreshed from Google Patents.
US5380373A
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Floating single crystal thin film fabrication method
Assignee: Ricoh Seiki Co Ltd
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Filing: 1993-07-14
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Granted: 1995-01-10
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Expires: 2013-07-14
Abstract
Abstract The present invention comprises a first process to enclose a floating single crystal thin film with a enclosure material which is hardly affected by an isotropic etchant using a face with the lowest etch rate against an anisotropic etchant as a front surface of a single crystal substrate, a second process to cover a portion of or the entire surface of the single crystal substrate with a cover material which is hardly etched by the anisotropic etchant nor by the isotropic etchant, a third process to form an etched groove by etching and removing a portion of the single crystal substrate in the outer side or under a region enclosed by the enclosure material using the isotropic etchant, and a fourth process to deposit a floating single crystal thin film by etching and removing a portion of the single crystal thin film using the anisotropic etchant and making use of the etched groove.
Inventors
- 👤 Mitsuteru Kimura
- 👤 Noriaki Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 15:23
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/68; G01F1/684; G01F1/6845; H; H10; H10F; H10F71/00; H10F71/121; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/547; Y02P; Y02P70/00; Y02P70/50
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
138 words
A method of forming a floating portion of a single crystal substrate which comprises: surrounding a surface portion of a single crystal substrate with an enclosure material which is resistant to etching by an anisotropic etchant, said surrounded surface portion having a depth which extends below a surface of said single crystal substrate; covering at least said enclosure material and another surface portion of the single crystal substrate with a covering material which is resistant to etching by said anisotropic etchant; forming a well in said single crystal substrate on each opposite outer side of said enclosure material; and forming a floating portion of a single crystal substrate by etching a portion of said single crystal substrate with said anisotropic etchant, said etched portion of said single crystal substrate extending between said wells and beneath said enclosure material.
Claim 2
Independent Claim
138 words
A method of forming a floating portion of a single crystal substrate which comprises: surrounding a surface portion of a single crystal substrate with an enclosure material which is resistant to etching by an anisotropic etchant, said surrounded surface portion having a depth which extends below a surface of said single crystal substrate; covering at least said enclosure material and another surface portion of the single crystal substrate with a covering material which is resistant to etching by said anisotropic etchant; forming a well in said single crystal substrate on each opposite outer side of said enclosure material; and forming a floating portion of a single crystal substrate by etching a portion of said single crystal substrate with said anisotropic etchant, said etched portion of said single crystal substrate extending between said wells and beneath said enclosure material.
Claim 3
Independent Claim
176 words
A method of forming a floating portion of a single crystal substrate which comprises: covering at least a portion of the surface of a single crystal substrate with a first cover material which is resistant to etching by an anisotropic etchant; forming a well in said first covering material and in said underlying single crystal substrate; surrounding a portion said single crystal substrate with an enclosure material which is resistant to etching by said anisotropic etchant, said surrounded portion having a depth which extends below a surface of said single crystal substrate; covering at least said enclosure material and another portion of the single crystal substrate with a covering material which is resistant to etching by said anisotropic etchant; forming a well in said single crystal substrate on each opposite outer side of said enclosure material; and forming a floating portion of a single crystal substrate by etching a portion of said single crystal substrate with said anisotropic etchant, said etched portion of said single crystal substrate extending between said wells and beneath said enclosure material.
Claim 4
Independent Claim
176 words
A method of forming a floating portion of a single crystal substrate which comprises: covering at least a portion of the surface of a single crystal substrate with a first cover material which is resistant to etching by an anisotropic etchant; forming a well in said first covering material and in said underlying single crystal substrate; surrounding a portion said single crystal substrate with an enclosure material which is resistant to etching by said anisotropic etchant, said surrounded portion having a depth which extends below a surface of said single crystal substrate; covering at least said enclosure material and another portion of the single crystal substrate with a covering material which is resistant to etching by said anisotropic etchant; forming a well in said single crystal substrate on each opposite outer side of said enclosure material; and forming a floating portion of a single crystal substrate by etching a portion of said single crystal substrate with said anisotropic etchant, said etched portion of said single crystal substrate extending between said wells and beneath said enclosure material.
Claim 5
Dependent Claim
12 words
The method of claim 1, wherein said anisotropic etchant comprises potassium hydroxide.
Claim 6
Dependent Claim
13 words
The method of claim 1, wherein said enclosure material comprises boron doped silicon.
Claim 7
Dependent Claim
16 words
The method of claim 1, wherein covering materials comprises a double layer of gold and titanium.
Claim 8
Dependent Claim
12 words
The method of claim 2, wherein said anisotropic etchant comprises potassium hydroxide.
Claim 9
Dependent Claim
13 words
The method of claim 2, wherein said enclosure material comprises boron doped silicon.
Claim 10
Dependent Claim
16 words
The method of claim 2, wherein covering materials comprises a double layer of gold and titanium.
Claim 11
Dependent Claim
115 words
A floating single crystal thin film comprising: a) a single crystal substrate; b) an enclosure material having an impurity concentration therein formed in said single crystal substrate so as to enclose a portion of said single crystal substrate; c) a covering layer formed on a portion of said single crystal substrate and said enclosure material; d) at least two windows extending through said insulating layer and into said single crystal substrate; e) a hollow through section formed in said single crystal substrate extending between said windows and beneath said portion of said single crystal substrate; f) wherein a single crystal thin film is formed above said hollow through sections and enclosed by said enclosure material.
Claim 12
Dependent Claim
115 words
A floating single crystal thin film comprising: a) a single crystal substrate; b) an enclosure material having an impurity concentration therein formed in said single crystal substrate so as to enclose a portion of said single crystal substrate; c) a covering layer formed on a portion of said single crystal substrate and said enclosure material; d) at least two windows extending through said insulating layer and into said single crystal substrate; e) a hollow through section formed in said single crystal substrate extending between said windows and beneath said portion of said single crystal substrate; f) wherein a single crystal thin film is formed above said hollow through sections and enclosed by said enclosure material.
Claim 13
Dependent Claim
20 words
The floating single crystal thin film of claim 9 wherein said single crystal substrate is silicon having a (111) orientation.
Claim 14
Dependent Claim
16 words
The floating single crystal thin film of claim 9 wherein said enclosure material is boron-doped silicon.
Claim 15
Dependent Claim
35 words
The floating single crystal thin film of claim 9 wherein one or both of said single crystal substrate and said covering layer is a material having a low rate of etching against an anisotropic etchant.
Claim 16
Dependent Claim
38 words
The floating single crystal thin film of claim 9 wherein a metallic cover layer is formed on said insulating layer prior to formation of said windows and said hollow through section and is subsequently removed after said formation.
Claim 17
Dependent Claim
22 words
The floating single crystal thin film of claim 13 wherein said metallic cover layer is a dual layer of gold and titanium.
Claim 18
Dependent Claim
115 words
A floating single crystal thin film comprising: a) a single crystal substrate; b) an insulating layer formed on upper and lower main surfaces of said single crystal substrate; c) at least a pair of first windows formed through said insulating layer on said upper surface and extending into said single crystal substrate; d) a second window formed through said insulating layer formed on said lower surface and into said single crystal substrate, said second window interconnecting said pair of first windows; and e) said pair of first windows having a covering layer formed on surfaces thereof; f) wherein a single crystal thin film is formed above said second window and enclosed by said covering layer.
Claim 19
Dependent Claim
115 words
A floating single crystal thin film comprising: a) a single crystal substrate; b) an insulating layer formed on upper and lower main surfaces of said single crystal substrate; c) at least a pair of first windows formed through said insulating layer on said upper surface and extending into said single crystal substrate; d) a second window formed through said insulating layer formed on said lower surface and into said single crystal substrate, said second window interconnecting said pair of first windows; and e) said pair of first windows having a covering layer formed on surfaces thereof; f) wherein a single crystal thin film is formed above said second window and enclosed by said covering layer.
Claim 20
Dependent Claim
35 words
The floating single crystal thin film of claim 15 wherein one or both of said single crystal substrate and said covering layer is a material having a low rate of etching against an anisotropic etchant.
Claim 21
Dependent Claim
20 words
The floating single crystal thin film of claim 15 wherein said single crystal substrate is silicon having a (111) orientation.
Claim 22
Dependent Claim
17 words
The floating single crystal thin film of claim 9 wherein said single crystal substrate is gallium arsenide.
Claim 23
Dependent Claim
17 words
The floating single crystal thin film of claim 15 wherein said single crystal substrate is gallium arsenide.
References Cited (Backward Citations)
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| 3.5 Years (Year 4) | 1998-01-09 | 1998-07-11 | 1999-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-01-09 | 2002-07-11 | 2003-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-01-09 | 2006-07-11 | 2007-01-10 | $7700.00 | Window Closed / Lapsed |