US6093330A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microfabrication process for enclosed microstructures
Assignee: PENTECH FINANCIAL SERVICES Inc
•
Filing: 1997-06-02
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Granted: 2000-07-25
•
Expires: 2017-06-02
Abstract
Abstract A single-mask process for fabricating enclosed, micron-scale subsurface cavities in a single crystal silicon substrate includes the steps of patterning the substrate to form vias, etching the cavities through the vias, and sealing the vias. Single cavities of any configuration may be produced, but a preferred embodiment includes closely spaced cavity pairs. The cavities may be separated by a thin membrane, or may be merged to form an enlarged merged cavity having an overhanging bar to which electrical leads may be connected. A three-mask process for fabricating enclosed cavities with electrical contacts and electrical connections is also disclosed.
Inventors
- 👤 John M. Chong
- 👤 Scott G. Adams
- 👤 Noel C. MacDonald
- 👤 Kevin A. Shaw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:20
CPC Classifications
B; B81; B81C; B81C1/00; B81C1/00015; B81C1/00134; B81C1/0015; B81C1/00023; B81C1/00047; B81C1/00055; B81C1/00071; B81B; B81B2203/00; B81B2203/03; B81B2203/0323; B81B2203/0338; B81C2201/00; B81C2201/05; B81C2201/053; B81C2203/00; B81C2203/01; B81C2203/0136
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
104 words
A process for fabrication of subsurface structures comprising: producing, on a surface of a substrate, a mask having a pattern defining the location and configuration of a subsurface cavity to be formed; vertically etching said substrate through said mask pattern to produce in said substrate at least one via channel corresponding to said pattern; isotropically etching said substrate through said via channel to produce within said substrate and below the surface thereof said subsurface cavity; and etching said substrate around said cavity and said via channel to produce a structure which is at least partially released from said substrate and which contains said cavity.
Claim 2
Dependent Claim
104 words
A process for fabrication of subsurface structures comprising: producing, on a surface of a substrate, a mask having a pattern defining the location and configuration of a subsurface cavity to be formed; vertically etching said substrate through said mask pattern to produce in said substrate at least one via channel corresponding to said pattern; isotropically etching said substrate through said via channel to produce within said substrate and below the surface thereof said subsurface cavity; and etching said substrate around said cavity and said via channel to produce a structure which is at least partially released from said substrate and which contains said cavity.
Claim 3
Dependent Claim
24 words
The process of claim 1, wherein said vertical etching of said substrate produces a via channel having substantially vertical sidewalls leading to said cavity.
Claim 4
Dependent Claim
22 words
The process of claim 2, further including depositing a protective layer on said via channel sidewalls prior to isotropically etching said substrate.
Claim 5
Dependent Claim
20 words
The process of claim 1, further including controlling said isotropic substrate etch to regulate the dimensions of said subsurface cavity.
Claim 6
Dependent Claim
42 words
The process of claim 1, wherein the step of producing said mask pattern includes defining the location and configuration of at least two closely-spaced cavities, and wherein etching said substrate through said pattern mask produces corresponding closely-spaced via channels in said surface.
Claim 7
Dependent Claim
21 words
The process of claim 5, wherein isotropically etching said substrate includes etching subsurface channels corresponding to each of said via cavities.
Claim 8
Dependent Claim
20 words
The process of claim 6, further including depositing a protective layer in said via channels prior to said isotropic etch.
Claim 9
Dependent Claim
28 words
The process of claim 6, further including controlling the duration of said isotropic substrate etching of said subsurface cavities to produce a membrane wall between adjacent subsurface cavities.
Claim 10
Dependent Claim
24 words
The process of claim 6, further including controlling the duration of said isotropic substrate etch to produce cavities having varying diameters along their lengths.
Claim 11
Dependent Claim
29 words
The process of claim 6, further including controlling the duration of said isotropic substrate etch to cause said subsurface cavities to merge to form a single subsurface merged cavity.
Claim 12
Dependent Claim
32 words
The process of claim 10, further including defining in said mask pattern the number and spacing of said cavities to thereby define the dimensions of said subsurface merged cavity upon said merger.
Claim 13
Dependent Claim
33 words
The process of claim 11, wherein said cavities are elongated, and further including varying dimensions of said merged cavity along the length thereof by varying the number and spacing of said elongated cavities.
Claim 14
Dependent Claim
32 words
The process of claim 10, further including forming from said substrate between said vias at least one overhanging bar above said single subsurface merged cavity, said bar being separated from said substrate.
Claim 15
Dependent Claim
18 words
The process of claim 13, further including forming an electrical contact on at least one said overhanging bar.
Claim 16
Dependent Claim
28 words
The process of claim 13, further including forming dielectric support bridges for said at least one overhanging bar, said bridges extending between said overhanging bar and said substrate.
Claim 17
Dependent Claim
32 words
The process of claim 15, further including: forming at least one electrical contact on said at least one overhanging bar; and fabricating an electrical connector between said contact and a second contact.
Claim 18
Dependent Claim
18 words
The process of claim 6, further including forming electrical contacts in communication with each of said subsurface cavities.
Claim 19
Dependent Claim
36 words
The process of claim 6, further including: controlling the duration of said isotropic substrate etch to produce a membrane wall between adjacent cavities; and forming an electrical contact on said substrate in contact with said membrane.
Claim 20
Dependent Claim
24 words
The process of claim 1, further including forming a dielectric layer on an inner surface of said cavity prior to sealing said via channel.
Claim 21
Dependent Claim
21 words
The process of claim 1, further including shaping said cavity by an anisotropic etch through said via channel prior to sealing.
Claim 22
Dependent Claim
24 words
The process of claim 1, wherein etching around said cavity includes substantially completely releasing said structure to produce a cantilevered beam containing said cavity.
Claim 23
Dependent Claim
32 words
The process of claim 1, wherein etching said substrate around said cavity produces a structure having an upper thin wall portion enclosing said cavity and a lower portion connected to said substrate.
Claim 24
Dependent Claim
19 words
The process of claim 1, wherein etching said substrate around said cavity produces a released beam containing said cavity.
Claim 25
Dependent Claim
19 words
The process of claim 22, wherein etching said substrate around said cavity exposes a cavity wall surrounding said cavity.
Claim 26
Dependent Claim
15 words
The process of claim 1, further including sealing said via channel to close said cavity.
Claim 27
Dependent Claim
22 words
The process of claim 25, wherein isotropically etching said substrate includes etching intersecting subsurface cavities, one said cavity having a dividing membrane.
Claim 28
Dependent Claim
68 words
A process for the fabrication of subsurface structures, comprising: forming in the surface of a substrate an elongated via channel having a width sufficiently large to permit isotropic etching of the substrate through the via channel; isotropically etching the substrate below the via channel to produce an elongated cavity within the substrate; and at least partially releasing an elongated beam within said substrate and containing said elongated cavity.
Claim 29
Dependent Claim
68 words
A process for the fabrication of subsurface structures, comprising: forming in the surface of a substrate an elongated via channel having a width sufficiently large to permit isotropic etching of the substrate through the via channel; isotropically etching the substrate below the via channel to produce an elongated cavity within the substrate; and at least partially releasing an elongated beam within said substrate and containing said elongated cavity.
Claim 30
Dependent Claim
33 words
The process of claim 27, wherein at least partially releasing an elongated beam includes etching said substrate around said cavity to produce an exposed wall for at least a part of said cavity.
Claim 31
Dependent Claim
26 words
The process of claim 27, wherein at least partially releasing an elongated beam includes etching said substrate to produce a cantilevered beam containing said elongated cavity.
Claim 32
Dependent Claim
40 words
The process of claim 27, wherein at least partially releasing an elongated beam includes: thermally oxidizing said cavity to provide an oxide wall surrounding the cavity; and etching said substrate to expose at least a portion of said oxide wall.
Claim 33
Dependent Claim
25 words
The process of claim 30, wherein etching said substrate includes completely releasing a region of said beam to expose said oxide wall around said cavity.
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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) | 2003-07-25 | 2004-01-24 | 2004-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-07-25 | 2008-01-24 | 2008-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-07-25 | 2012-01-24 | 2012-07-25 | $7700.00 | Window Closed / Lapsed |