U.S. patent application number 12/637659 was filed with the patent office on 2010-06-03 for complex microdevices and apparatus and methods for fabricating such devices.
This patent application is currently assigned to Microfabrica Inc.. Invention is credited to Christopher A. Bang, Adam L. Cohen, John D. Evans, Michael S. Lockard.
Application Number | 20100133952 12/637659 |
Document ID | / |
Family ID | 35148880 |
Filed Date | 2010-06-03 |
United States Patent
Application |
20100133952 |
Kind Code |
A1 |
Bang; Christopher A. ; et
al. |
June 3, 2010 |
Complex Microdevices and Apparatus and Methods for Fabricating Such
Devices
Abstract
Various embodiments of the invention are directed to various
microdevices including sensors, actuators, valves, scanning
mirrors, accelerometers, switches, and the like. In some
embodiments the devices are formed via electrochemical fabrication
(EFAB.RTM.).
Inventors: |
Bang; Christopher A.; (San
Diego, CA) ; Cohen; Adam L.; (Los Angeles, CA)
; Lockard; Michael S.; (Lake Elizabeth, CA) ;
Evans; John D.; (Arlington, VA) |
Correspondence
Address: |
MICROFABRICA INC.;ATT: DENNIS R. SMALLEY
7911 HASKELL AVENUE
VAN NUYS
CA
91406
US
|
Assignee: |
Microfabrica Inc.
|
Family ID: |
35148880 |
Appl. No.: |
12/637659 |
Filed: |
December 14, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12099976 |
Apr 9, 2008 |
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12637659 |
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11139391 |
May 27, 2005 |
7372616 |
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12099976 |
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10313795 |
Dec 6, 2002 |
7185542 |
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11139391 |
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60364261 |
Mar 13, 2002 |
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60340372 |
Dec 6, 2001 |
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60379133 |
May 7, 2002 |
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60415371 |
Oct 1, 2002 |
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60379135 |
May 7, 2002 |
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60379182 |
May 7, 2002 |
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60430809 |
Dec 3, 2002 |
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60379184 |
May 7, 2002 |
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60415374 |
Oct 1, 2002 |
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60392531 |
Jun 27, 2002 |
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60422007 |
Oct 29, 2002 |
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60422982 |
Nov 1, 2002 |
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60429483 |
Nov 26, 2002 |
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60429484 |
Nov 26, 2002 |
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Current U.S.
Class: |
310/309 ;
205/118; 205/170 |
Current CPC
Class: |
B33Y 10/00 20141201;
H02N 1/008 20130101; C25D 1/003 20130101; B81C 1/0019 20130101 |
Class at
Publication: |
310/309 ;
205/170; 205/118 |
International
Class: |
H02N 1/00 20060101
H02N001/00; C25D 5/10 20060101 C25D005/10; C25D 5/02 20060101
C25D005/02 |
Claims
1. A microdevice comprising at least one of: a. a sensor comprising
at least two sets of capacitor plates wherein each set of plates
comprises a plurality of plates; b. an actuator comprising at least
two sets of capacitor plates wherein each set includes a plurality
of plates and wherein a motion of the actuator is perpendicular to
a plane of the plates; c. an actuator comprising at least two sets
of capacitor plates wherein each set includes a plurality of plates
and wherein a motion of the actuator is in a direction parallel to
a plane of the plates, and wherein a portion of the plurality of
plates in one set are positioned in a first plane while another
portion of the plurality of the plates of the one set are
positioned in a second plane offset from the first plane; d. an
actuator comprising at least two sets of capacitor plates wherein
each set includes a plurality of plates and wherein a motion of the
actuator is in a direction parallel to a plane of the plates, and
wherein the plurality of plates in one set are positioned in an
array that extends in three dimensions; e. an electrostatic
actuator comprising at least one moveable member and at least one
actuation electrode for causing movement of the moveable member
wherein the electrode and/or the moveable member is configured to
have a contour that leads to a spacing between moveable member and
the electrode when the moveable member is in its deflected position
toward the electrode which is more uniform than when the moveable
member is in an undeflected position; f. an electrostatic actuator
comprising at least one moveable member and at least one actuation
electrode for causing movement of the moveable member wherein the
electrode and/or the moveable member has a configuration that
brings portions of the electrode and member closer together without
significantly interfering with the movement of the member; g. an
electrostatic actuator comprising at least one moveable member and
at least one actuation electrode for causing movement of the
moveable member wherein the electrode has at least one sidewall or
at least one protrusion in a region that reduces the separation
between the electrode and the member without hindering the motion
of the member; h. an electrostatic actuator comprising at least one
moveable member and at least two actuation electrodes that can be
activated to create forces that pull the moveable member in
opposing directions; i. an electrostatically actuated micro-mirror
scanning system comprising contoured electrodes that allow a
reduced drive voltage without hindering mirror movement; j. a
structure comprising a multi-level micro flow channel; or k. a
metal mold have a plurality of levels having features with
dimensions on the order of 10s of microns or less.
2. A method of fabricating a multi-layer structure, comprising: (i)
forming a first layer on a substrate comprising deposition of at
least one sacrificial material and deposition of at least one
structural material wherein the deposited sacrificial material and
the deposited structural material are planarized to have a common
height to set a boundary level for the first layer; (ii) forming
additional layers adjacent to and adhered to previously formed
layers, wherein the formation of each layer comprises deposition of
at least one sacrificial material and deposition of at least one
structural material and wherein the sacrificial material and the
structural material for each additional layer are planarized to
have a common height to set a boundary level for each additional
layer; and (iii) after formation of the additional layers, etching
at least one sacrificial material from a plurality of layers to
reveal the structure, wherein structure is configured to function
as a check valve, and comprises: a valve body surrounding a
passage; a valve plate supported by one or more springs relative to
the valve body and capable of movement relative to the valve body
to allow opening and closing of the passage.
3. The method of claim 2 wherein the check valve is opened when
sufficient pressure is applied to a selected side of the valve
plate.
4. The method of claim 2 wherein the check valve is closed when
sufficient pressure is applied to a selected side of the valve
plate.
5. The method of claim 2 wherein at least one sacrificial material
comprises an electroplated metal and at least one structural
material comprises an electroplated metal.
6. The method of claim 2 wherein a second structural material
applied to at least one layer comprises a shape memory alloy.
7. The method of claim 6 wherein the second structural material is
applied into a void formed by etching into a portion of previously
deposited material.
8. The method of claim 7 wherein the valve can be set into a closed
state or an opened state by manipulation of the shape memory alloy
which state may be changed by application of sufficient pressure on
a selected side of the valve plate.
9. A method of fabricating a multi-layer structure, comprising: (i)
forming a first layer on a substrate comprising deposition of at
least one sacrificial material and deposition of at least one
structural material wherein the deposited sacrificial material and
the deposited structural material are planarized to have a common
height to set a boundary level for the first layer; (ii) forming
additional layers adjacent to and adhered to previously formed
layers, wherein the formation of each layer comprises deposition of
at least one sacrificial material and deposition of at least one
structural material and wherein the sacrificial material and the
structural material for each additional layer are planarized to
have a common height to set a boundary level for each additional
layer; and (iii) after formation of the additional layers, etching
at least one sacrificial material from a plurality of layers to
reveal the structure, wherein structure is configured to function
as a bellows controlled valve, and comprises: a valve body
surrounding a passage; a valve plate supported a bellows relative
to the valve body and capable of movement relative to the valve
body to allow opening and closing of the passage.
10. The method of claim 9 wherein at least one sacrificial material
comprises an electroplated metal and at least one structural
material comprises an electroplated metal.
11. The method of claim 10 wherein the bellows comprises a cavity
and a passage for movement of a pneumatic control fluid.
12. The method of claim 11 wherein the bellows comprises a cavity
and a passage for movement of a pneumatic control fluid.
13. A method of fabricating a multi-layer structure, comprising:
(i) forming a first layer on a substrate comprising deposition of
at least one sacrificial material and deposition of at least one
structural material wherein the deposited sacrificial material and
the deposited structural material are planarized to have a common
height to set a boundary level for the first layer; (ii) forming
additional layers adjacent to and adhered to previously formed
layers, wherein the formation of each layer comprises deposition of
at least one sacrificial material and deposition of at least one
structural material and wherein the sacrificial material and the
structural material for each additional layer are planarized to
have a common height to set a boundary level for each additional
layer; and (iii) after formation of the additional layers, etching
at least one sacrificial material from a plurality of layers to
reveal the structure, wherein structure is configured to function
as a bistable valve, and comprises: a valve body surrounding a
passage; a valve plate supported by one or more controllable
supports relative to the valve body and capable of moving a valve
plate from a stable passage closed position to a stable passage
open position.
14. The method of claim 13 wherein the valve is opened when
sufficient pressure is applied to a selected side of the valve
plate.
15. The method of claim 13 wherein the valve is closed when
sufficient pressure is applied to a selected side of the valve
plate.
16. The method of claim 13 wherein at least one sacrificial
material comprises an electroplated metal and at least one
structural material comprises an electroplated metal.
17. The method of claim 13 wherein a second structural material
applied to at least one layer comprises a magnetic material.
18. The method of claim 13 wherein a second structural material
applied to at least one layer comprises a dielectric material.
19. The method of claim 13 wherein the valve can be moved between
states by a temporarily controlled actuator.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Non-Provisional
patent application Ser. No. 12/099,976 (Microfabrica docket number
P-U5045-C-MF), filed Apr. 9, 2008 which in turn is a divisional of
U.S. Non-Provisional patent application Ser. No. 11/139,391
(Microfabrica docket no. P-U5045-B-MF), filed May 27, 2005 which in
turn is a continuation of U.S. Non-Provisional patent application
Ser. No. 10/313,795 (Microfabrica docket no. P-U5045-A-MF) filed on
Dec. 6, 2002 which in turn claims benefit to U.S. Provisional
Patent Application Nos. 60/364,261 filed on Mar. 13, 2002;
60/340,372 filed on Dec. 6, 2001; 60/379,133 filed on May 7, 2002;
60/415,371 filed on Oct. 1, 2002; 60/379,135 filed on May 7, 2002;
60/379,182 filed on May 7, 2002; 60/430,809 filed on Dec. 3, 2002;
60/379,184 filed on May 7, 2002; 60/415,374 filed on Oct. 1, 2002;
60/392,531 filed on Jun. 27, 2002; 60/422,007 filed on Oct. 29,
2002; 60/422,982 filed on Nov. 1, 2002; 60/429,483 filed on Nov.
26, 2002; 60/429,484 filed on Nov. 26, 2002. Each of these
applications is incorporated herein by reference as if set forth in
full. U.S. Patent Application Nos. 60/379,177 filed on May 7, 2002,
60/379,130, filed on May 7, 2002, and Ser. No. 10/309,521
(Microfabrica docket no. P-U5044-A-MF), filed Dec. 3, 2002 are also
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of
miniature devices while specific embodiments are directed to
various sensors, various actuators, valves, structures possessing
complex fluid flow paths, tooling, electrical devices, as well as
other devices, apparatus for producing complex miniature devices,
and methods for producing complex miniature devices. In some
embodiments, fabrication of devices occur via Electrochemical
Fabrication techniques that may involve the formation of a
plurality of layers of material formed and adhered to one another
via one or more of selective and/or blanket depositions (e.g. by
electroplating), selective and/or blanket etching (e.g. by chemical
or electrochemical processes), planarization and/or polishing,
and/or other forms of deposition.
BACKGROUND OF THE INVENTION
[0003] A technique for forming three-dimensional structures (e.g.
parts, components, devices, and the like) from a plurality of
adhered layers was invented by Adam L. Cohen and is known as
Electrochemical Fabrication. It is being commercially pursued by
Microfabrica.RTM. Inc. (formerly MEMGen Corporation) of Van Nuys,
Calif. under the name EFAB.RTM.. This technique was described in
U.S. Pat. No. 6,027,630, issued on Feb. 22, 2000. This
electrochemical deposition technique allows the selective
deposition of a material using a unique masking technique that
involves the use of a mask that includes patterned conformable
material on a support structure that is independent of the
substrate onto which plating will occur. When desiring to perform
an electrodeposition using the mask, the conformable portion of the
mask is brought into contact with a substrate while in the presence
of a plating solution such that the contact of the conformable
portion of the mask to the substrate inhibits deposition at
selected locations. For convenience, these masks might be
generically called conformable contact masks; the masking technique
may be generically called a conformable contact mask plating
process. More specifically, in the terminology of Microfabrica.RTM.
Inc. (formerly MEMGen Corporation) of Van Nuys, Calif. such masks
have come to be known as INSTANT MASKS.TM. and the process known as
INSTANT MASKING.TM. or INSTANT MASK.TM. plating. Selective
depositions using conformable contact mask plating may be used to
form single layers of material or may be used to form multi-layer
structures. The teachings of the '630 patent are hereby
incorporated herein by reference as if set forth in full herein.
Since the filing of the patent application that led to the above
noted patent, various papers about conformable contact mask plating
(i.e. INSTANT MASKING) and electrochemical fabrication have been
published: [0004] 1. A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U.
Frodis and P. Will, "EFAB: Batch production of functional,
fully-dense metal parts with micro-scale features", Proc. 9th Solid
Freeform Fabrication, The University of Texas at Austin, p 161,
August 1998. [0005] 2. A. Cohen, G. Zhang, F. Tseng, F. Mansfeld,
U. Frodis and P. Will, "EFAB: Rapid, Low-Cost Desktop
Micromachining of High Aspect Ratio True 3-D MEMS", Proc. 12th IEEE
Micro Electro Mechanical Systems Workshop, IEEE, p 244, January
1999. [0006] 3. A. Cohen, "3-D Micromachining by Electrochemical
Fabrication", Micromachine Devices, March 1999. [0007] 4. G. Zhang,
A. Cohen, U. Frodis, F. Tseng, F. Mansfeld, and P. Will, "EFAB:
Rapid Desktop Manufacturing of True 3-D Microstructures", Proc. 2nd
International Conference on Integrated MicroNanotechnology for
Space Applications, The Aerospace Co., April 1999. [0008] 5. F.
Tseng, U. Frodis, G. Zhang, A. Cohen, F. Mansfeld, and P. Will,
"EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures using
a Low-Cost Automated Batch Process", 3rd International Workshop on
High Aspect Ratio MicroStructure Technology (HARMST'99), June 1999.
[0009] 6. A. Cohen, U. Frodis, F. Tseng, G. Zhang, F. Mansfeld, and
P. Will, "EFAB: Low-Cost, Automated Electrochemical Batch
Fabrication of Arbitrary 3-D Microstructures", Micromachining and
Microfabrication Process Technology, SPIE 1999 Symposium on
Micromachining and Microfabrication, September 1999. [0010] 7. F.
Tseng, G. Zhang, U. Frodis, A. Cohen, F. Mansfeld, and P. Will,
"EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures using
a Low-Cost Automated Batch Process", MEMS Symposium, ASME 1999
International Mechanical Engineering Congress and Exposition,
November, 1999. [0011] 8. A. Cohen, "Electrochemical Fabrication
(EFAB.TM.)", Chapter 19 of The MEMS Handbook, edited by Mohamed
Gad-El-Hak, CRC Press, 2002. [0012] 9. "Microfabrication--Rapid
Prototyping's Killer Application", pages 1-5 of the Rapid
Prototyping Report, CAD/CAM Publishing, Inc., June 1999.
[0013] The disclosures of these nine publications are hereby
incorporated herein by reference as if set forth in full
herein.
[0014] The electrochemical deposition process may be carried out in
a number of different ways as set forth in the above patent and
publications. In one form, this process involves the execution of
three separate operations during the formation of each layer of the
structure that is to be formed: [0015] 1. Selectively depositing at
least one material by electrodeposition upon one or more desired
regions of a substrate. [0016] 2. Then, blanket depositing at least
one additional material by electrodeposition so that the additional
deposit covers both the regions that were previously selectively
deposited onto, and the regions of the substrate that did not
receive any previously applied selective depositions. [0017] 3.
Finally, planarizing the materials deposited during the first and
second operations to produce a smoothed surface of a first layer of
desired thickness having at least one region containing the at
least one material and at least one region containing at least the
one additional material.
[0018] After formation of the first layer, one or more additional
layers may be formed adjacent to the immediately preceding layer
and adhered to the smoothed surface of that preceding layer. These
additional layers are formed by repeating the first through third
operations one or more times wherein the formation of each
subsequent layer treats the previously formed layers and the
initial substrate as a new and thickening substrate.
[0019] Once the formation of all layers has been completed, at
least a portion of at least one of the materials deposited is
generally removed by an etching process to expose or release the
three-dimensional structure that was intended to be formed.
[0020] The preferred method of performing the selective
electrodeposition involved in the first operation is by conformable
contact mask plating. In this type of plating, one or more
conformable contact (CC) masks are first formed. The CC masks
include a support structure onto which a patterned conformable
dielectric material is adhered or formed. The conformable material
for each mask is shaped in accordance with a particular
cross-section of material to be plated. At least one CC mask is
needed for each unique cross-sectional pattern that is to be
plated.
[0021] The support for a CC mask is typically a plate-like
structure formed of a metal that is to be selectively electroplated
and from which material to be plated will be dissolved. In this
typical approach, the support will act as an anode in an
electroplating process. In an alternative approach, the support may
instead be a porous or otherwise perforated material through which
deposition material will pass during an electroplating operation on
its way from a distal anode to a deposition surface. In either
approach, it is possible for CC masks to share a common support,
i.e. the patterns of conformable dielectric material for plating
multiple layers of material may be located in different areas of a
single support structure. When a single support structure contains
multiple plating patterns, the entire structure is referred to as
the CC mask while the individual plating masks may be referred to
as "submasks". In the present application such a distinction will
be made only when relevant to a specific point being made.
[0022] In preparation for performing the selective deposition of
the first operation, the conformable portion of the CC mask is
placed in registration with and pressed against a selected portion
of the substrate (or onto a previously formed layer or onto a
previously deposited portion of a layer) on which deposition is to
occur. The pressing together of the CC mask and substrate occur in
such a way that all openings, in the conformable portions of the CC
mask contain plating solution. The conformable material of the CC
mask that contacts the substrate acts as a barrier to
electrodeposition while the openings in the CC mask that are filled
with electroplating solution act as pathways for transferring
material from an anode (e.g. the CC mask support) to the
non-contacted portions of the substrate (which act as a cathode
during the plating operation) when an appropriate potential and/or
current are supplied.
[0023] An example of a CC mask and CC mask plating are shown in
FIGS. 1A-10. FIG. 1A shows a side view of a CC mask 8 consisting of
a conformable or deformable (e.g. elastomeric) insulator 10
patterned on an anode 12. The anode has two functions. FIG. 1A also
depicts a substrate 6 separated from mask 8. One is as a supporting
material for the patterned insulator 10 to maintain its integrity
and alignment since the pattern may be topologically complex (e.g.,
involving isolated "islands" of insulator material). The other
function is as an anode for the electroplating operation. CC mask
plating selectively deposits material 22 onto a substrate 6 by
simply pressing the insulator against the substrate then
electrodepositing material through apertures 26a and 26b in the
insulator as shown in FIG. 1B. After deposition, the CC mask is
separated, preferably non-destructively, from the substrate 6 as
shown in FIG. 1C. The CC mask plating process is distinct from a
"through-mask" plating process in that in a through-mask plating
process the separation of the masking material from the substrate
would occur destructively. As with through-mask plating, CC mask
plating deposits material selectively and simultaneously over the
entire layer. The plated region may consist of one or more isolated
plating regions where these isolated plating regions may belong to
a single structure that is being formed or may belong to multiple
structures that are being formed simultaneously. In CC mask plating
as individual masks are not intentionally destroyed in the removal
process, they may be usable in multiple plating operations.
[0024] Another example of a CC mask and CC mask plating is shown in
FIGS. 1D-1F. FIG. 1D shows an anode 12' separated from a mask 8'
that comprises a patterned conformable material 10' and a support
structure 20. FIG. 1D also depicts substrate 6 separated from the
mask 8'. FIG. 1E illustrates the mask 8' being brought into contact
with the substrate 6. FIG. 1F illustrates the deposit 22' that
results from conducting a current from the anode 12' to the
substrate 6. FIG. 1G illustrates the deposit 22' on substrate 6
after separation from mask 8'. In this example, an appropriate
electrolyte is located between the substrate 6 and the anode 12'
and a current of ions coming from one or both of the solution and
the anode are conducted through the opening in the mask to the
substrate where material is deposited. This type of mask may be
referred to as an anodeless INSTANT MASK.TM. (AIM) or as an
anodeless conformable contact (ACC) mask.
[0025] Unlike through-mask plating, CC mask plating allows CC masks
to be formed completely separate from the fabrication of the
substrate on which plating is to occur (e.g. separate from a
three-dimensional (3D) structure that is being formed). CC masks
may be formed in a variety of ways, for example, a
photolithographic process may be used. All masks can be generated
simultaneously, prior to structure fabrication rather than during
it. This separation makes possible a simple, low-cost, automated,
self-contained, and internally-clean "desktop factory" that can be
installed almost anywhere to fabricate 3D structures, leaving any
required clean room processes, such as photolithography to be
performed by service bureaus or the like.
[0026] An example of the electrochemical fabrication process
discussed above is illustrated in FIGS. 2A-2F. These figures show
that the process involves deposition of a first material 2 which is
a sacrificial material and a second material 4 which is a
structural material. The CC mask 8, in this example, includes a
patterned conformable material (e.g. an elastomeric dielectric
material) 10 and a support 12 which is made from deposition
material 2. The conformal portion of the CC mask is pressed against
substrate 6 with a plating solution 14 located within the openings
16 in the conformable material 10. An electric current, from power
supply 18, is then passed through the plating solution 14 via (a)
support 12 which doubles as an anode and (b) substrate 6 which
doubles as a cathode. FIG. 2A, illustrates that the passing of
current causes material 2 within the plating solution and material
2 from the anode 12 to be selectively transferred to and plated on
the cathode 6. After electroplating the first deposition material 2
onto the substrate 6 using CC mask 8, the CC mask 8 is removed as
shown in FIG. 2B. FIG. 2C depicts the second deposition material 4
as having been blanket-deposited (i.e. non-selectively deposited)
over the previously deposited first deposition material 2 as well
as over the other portions of the substrate 6. The blanket
deposition occurs by electroplating from an anode (not shown),
composed of the second material, through an appropriate plating
solution (not shown), and to the cathode/substrate 6. The entire
two-material layer is then planarized to achieve precise thickness
and flatness as shown in FIG. 2D. After repetition of this process
for all layers, the multi-layer structure 20 formed of the second
material 4 (i.e. structural material) is embedded in first material
2 (i.e. sacrificial material) as shown in FIG. 2E. The embedded
structure is etched to yield the desired device, i.e. structure 20,
as shown in FIG. 2F.
[0027] Various components of an exemplary manual electrochemical
fabrication system 32 are shown in FIGS. 3A-3C. The system 32
consists of several subsystems 34, 36, 38, and 40. The substrate
holding subsystem 34 is depicted in the upper portions of each of
FIGS. 3A to 3C and includes several components: (1) a carrier 48,
(2) a metal substrate 6 onto which the layers are deposited, and
(3) a linear slide 42 capable of moving the substrate 6 up and down
relative to the carrier 48 in response to drive force from actuator
44. Subsystem 34 also includes an indicator 46 for measuring
differences in vertical position of the substrate which may be used
in setting or determining layer thicknesses and/or deposition
thicknesses. The subsystem 34 further includes feet 68 for carrier
48 which can be precisely mounted on subsystem 36.
[0028] The CC mask subsystem 36 shown in the lower portion of FIG.
3A includes several components: (1) a CC mask 8 that is actually
made up of a number of CC masks (i.e. submasks) that share a common
support/anode 12, (2) precision X-stage 54, (3) precision Y-stage
56, (4) frame 72 on which the feet 68 of subsystem 34 can mount,
and (5) a tank 58 for containing the electrolyte 16. Subsystems 34
and 36 also include appropriate electrical connections (not shown)
for connecting to an appropriate power source for driving the CC
masking process.
[0029] The blanket deposition subsystem 38 is shown in the lower
portion of FIG. 3B and includes several components: (1) an anode
62, (2) an electrolyte tank 64 for holding plating solution 66, and
(3) frame 74 on which the feet 68 of subsystem 34 may sit.
Subsystem 38 also includes appropriate electrical connections (not
shown) for connecting the anode to an appropriate power supply for
driving the blanket deposition process.
[0030] The planarization subsystem 40 is shown in the lower portion
of FIG. 3C and includes a lapping plate 52 and associated motion
and control systems (not shown) for planarizing the
depositions.
[0031] Electrochemical Fabrication provides the ability to form
prototypes and commercial quantities of miniature objects, parts,
structures, devices, and the like at reasonable costs and in
reasonable times. In fact, Electrochemical Fabrication is an
enabler for the formation of many structures that were hitherto
impossible to produce. Electrochemical Fabrication opens the
spectrum for new designs and products in many industrial fields.
Even though Electrochemical Fabrication offers this new capability
and it is understood that Electrochemical Fabrication techniques
can be combined with designs and structures known within various
fields to produce new structures, certain uses for Electrochemical
Fabrication provide designs, structures, capabilities and/or
features not known or obvious in view of the state of the art.
[0032] A need exists in various fields for miniature devices having
improved characteristics, reduced fabrication times, reduced
fabrication costs, simplified fabrication processes, and/or more
independence between geometric configuration and the selected
fabrication process.
[0033] A need exists in the field of miniature device fabrication
for improved fabrication methods and apparatus.
SUMMARY OF THE INVENTION
[0034] An object of various aspects of the invention is to provide
devices (e.g. structures, objects, parts, components, and the like)
having improved characteristics.
[0035] An object of various aspects of the invention is to provide
reduced fabrication time for producing devices (e.g. prototype
devices).
[0036] An object of various aspects of the invention is to provide
reduced fabrication costs for producing devices (e.g. prototype
devices)
[0037] An object of various aspects of the invention is to provide
simplified fabrication processes for producing devices.
[0038] An object of various aspects of the invention is to provide
more independence between geometric configuration of a device and
the selected fabrication process.
[0039] A need exists in the field of miniature device fabrication
for improved fabrication methods and/or apparatus.
[0040] Other objects and advantages of various aspects of the
invention will be apparent to those of skill in the art upon review
of the teachings herein. The various aspects of the invention, set
forth explicitly herein or otherwise ascertained from the teachings
herein, may address any one of the above objects alone or in
combination, or alternatively may address some other object of the
invention ascertained from the teachings herein. It is not intended
that any specific aspect of the invention (that is explicitly set
forth below or that is ascertained from the teachings herein)
address any of the objects set forth above let alone address all of
these objects simultaneously, while some aspects may address one or
more of these objects or even all of these objects
simultaneously.
[0041] In a first aspect of the invention a sensor includes at
least two sets of capacitor plates wherein each set of plates
includes a plurality of plates.
[0042] In a second aspect of the invention, an actuator includes at
least two sets of capacitor plates wherein each set includes a
plurality of plates and wherein a motion of the actuator is
perpendicular to a plane of the plates.
[0043] In a third aspect of the invention, an actuator includes at
least two sets of capacitor plates wherein each set includes a
plurality of plates and wherein a motion of the actuator is in a
direction parallel to a plane of the plates, and wherein a portion
of the plurality of plates in one set are positioned in a first
plane while another portion of the plurality of the plates of the
one set are positioned in a second plane offset from the first
plane.
[0044] In a fourth aspect of the invention, an actuator includes at
least two sets of capacitor plates wherein each set includes a
plurality of plates and wherein a motion of the actuator is in a
direction parallel to a plane of the plates, and wherein the
plurality of plates in one set are positioned in an array that
extends in three dimensions.
[0045] In a variation of the first through fourth aspects of the
invention, the sensor or actuator is formed at least in part via
electrochemical fabrication.
[0046] In a fifth aspect of the invention an LVDT sensor is formed
at least in part via electrochemical fabrication.
[0047] In a sixth aspect of the invention an actuator is formed at
least in part via electrochemical fabrication.
[0048] In a seventh aspect of the invention a sensor is formed at
least in part via electrochemical fabrication.
[0049] In an eighth aspect of the invention an electrostatic
actuator includes at least one moveable member and at least one
actuation electrode for causing movement of the moveable member
wherein the electrode and/or the moveable member is configured to
have a contour that leads to a spacing between moveable member and
the electrode when the moveable member is in its deflected position
toward the electrode which is more uniform than when the moveable
member is in an undeflected position.
[0050] In a ninth aspect of the invention an electrostatic actuator
includes at least one moveable member and at least one actuation
electrode for causing movement of the moveable member wherein the
electrode and/or the moveable member has a configuration that
brings portions of the electrode and member closer together without
significantly interfering with the movement of the member.
[0051] In a tenth aspect of the invention an electrostatic actuator
includes at least one moveable member and at least one actuation
electrode for causing movement of the moveable member wherein the
electrode has at least one sidewall or at least one protrusion in a
region that reduces the separation between the electrode and the
member without hindering the motion of the member.
[0052] In an eleventh aspect of the invention an electrostatic
actuator includes at least one moveable member and at least two
actuation electrodes that can be activated to create forces that
pull the moveable member in opposing directions.
[0053] In a twelfth aspect of the invention an electrostatically
actuated micro-mirror scanning system includes contoured electrodes
that allow a reduced drive voltage without hindering mirror
movement.
[0054] In a thirteenth aspect of the invention a structure includes
a multi-level micro flow channel.
[0055] In a fourteenth aspect of the invention a metal mold
includes a plurality of levels having features with dimensions on
the order of 10s of microns or less.
[0056] In a fifteenth aspect of the invention a process for forming
a multilayer microdevice, comprising: (a) forming a layer of at
least one material on a substrate that may include one or more
previously deposited layers of one or more materials; (b) repeating
the forming operation of "(a)" one or more times to form at least
one subsequent layer on at least one previously formed layer to
build up a three-dimensional structure from a plurality layers;
wherein the forming of at least one layer, comprises: (1) supplying
a substrate on which one or more successive depositions of one or
more materials may have occurred; (2) supplying a mask having a
desired pattern or capable of being activated to effectively
deposit or etch a desired pattern of material; (3) bringing the
mask and the substrate into contact or proximity such that
electrochemical process pockets are formed having a desired
registration with respect to any previous depositions and providing
a desired electrolyte solution such that the solution is provided
within the electrochemical process pockets; and (4) applying a
desired electrical activation to cause a desired material to be
deposited onto the substrate or removed from the substrate in
preparation for deposition of a material onto the substrate;
wherein the microdevice includes one or more of the following: an
accelerometer, a switch, a valve, a 3-D tilt mirror, a fluid well,
a tool for producing other microstructures or structures with
micro-patterning, an actuator including a contoured electrode, a
bellows controlled valve, an actuator with pull down and pull up
electrodes, a valve comprising a shape memory device, a bistable
valve, a device at least partly surrounded by a conductive shield
wall.
[0057] In a sixteenth aspect of the invention a microdevice,
includes: a plurality of layers of successively deposited material,
wherein the deposition of each layer of material comprises, (a)
deposition of at least a first material; and (b) deposition of at
least a second material; and wherein at least a portion of the
first or second material is removed after deposition of the
plurality of layers; and wherein a structure resulting from the
deposition and the removal provides at least one structure that can
function as (1) an accelerometer, (2) a toroidal inductor, (3) a
switch, (4) a valve, (5) a helical inductor, (6) a 3-D tilt mirror,
(7) a fluid well, (8) an antenna, or (9) a mold.
[0058] In a seventeenth aspect of the invention a method of
manufacturing a microdevice includes: depositing a plurality of
adhered layers of material, wherein the deposition of each layer of
material comprises, a. selective deposition of at least a first
material; b deposition of at least a second material; and c.
planarization of at least a portion of the deposited material;
removing of at least a portion of the first or second material
after deposition of the plurality of layers; wherein a structure
resulting from the deposition and the removal provides at least one
structure that can function as (1) an accelerometer, (2) a toroidal
inductor, (3) a switch, (4) a valve, (5) a helical inductor, (6) a
3-D tilt mirror, (7) a fluid well, (8) an antenna, or (9) a
mold.
[0059] In a eighteenth aspect of the invention a microaccelerometer
includes: a proof mass; and at least one of a plurality of
spring-like structures for supporting the proof mass relative to a
substrate; where a portion of the plurality of spring-like
structures attach to the proof mass below a center of mass of the
proof mass and a plurality of the spring-like structures attach to
the proof mass above the center of mass of the proof mass; or a
plurality of spring-like structures for supporting the proof mass
relative to a substrate; where a portion of the plurality of
spring-like structures attach to the proof mass in a common plane
that includes the center of mass of mass of the proof mass.
[0060] In a nineteenth aspect of the invention a microvalve that
includes a valve seal and wherein at least one of the valve seat or
valve seal is supported by at least one corrugated support
structure.
[0061] In a twentieth aspect of the invention a 3-D tilt mirror
including features with dimensions on the order of 10s of microns
comprising a rotatable mirror structure with a reflective surface
that is supported by at least one spring-like structure, wherein
the spring-like structure is formed from the same material as that
which forms the reflective surface.
[0062] Further aspects of the invention will be understood by those
of skill in the art upon reviewing the teachings herein. Other
aspects of the invention may involve combinations of the above
noted aspects of the invention. Other aspects of the invention may
involve apparatus that can be used in implementing one or more of
the above method aspects of the invention. These other aspects of
the invention may provide various combinations of the aspects
presented above as well as provide other configurations,
structures, functional relationships, and processes that have not
been specifically set forth above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0063] FIGS. 1A-1C schematically depict a side view of various
stages of a CC mask plating process, while FIGS. 1D-G depict a side
view of various stages of a CC mask plating process using a
different type of CC mask.
[0064] FIGS. 2A-2F schematically depict side views of various
stages of an electrochemical fabrication process as applied to the
formation of a particular structure where a sacrificial material is
selectively deposited while a structural material is blanket
deposited.
[0065] FIGS. 3A-3C schematically depict side views of various
example subassemblies that may be used in manually implementing the
electrochemical fabrication method depicted in FIGS. 2A-2F.
[0066] FIG. 4 illustrates a pressure sensor utilizing a plurality
of stacked capacitor plates according to a first embodiment.
[0067] FIG. 5 illustrates an actuator utilizing a plurality of
stacked capacitor plates according to a second embodiment.
[0068] FIG. 6A illustrates a moveable portion of an actuator
according to a third embodiment where the moveable portion includes
a plurality of stacks and each stack includes a plurality of
individual capacitor plates.
[0069] FIG. 6B illustrates an expanded view of a portion of FIG.
6A.
[0070] FIG. 6C illustrates a top view of the top level of partially
overlapping fixed and moveable capacitor plates for the actuator of
FIGS. 6A and 6B.
[0071] FIG. 7 illustrates a schematic representation of a linear
variable differential transformer (LVDT).
[0072] FIGS. 8A-8D depict various views of a switch according to an
embodiment of the invention.
[0073] FIG. 9A illustrates the mechanical portion of an
accelerometer which includes a proof mass supported by eight
arms.
[0074] FIG. 9B illustrates a three-dimensional version of an
accelerometer that can be fabricated using electrochemical
fabrication.
[0075] FIG. 10 illustrates another embodiment of the present
invention where a check valve is provided.
[0076] FIG. 11 depicts a pressure controlled bellows valve that can
be made using electrochemical fabrication.
[0077] FIGS. 12A-12F depicts various stages in a process for
forming a valve according to an embodiment of the invention.
[0078] FIGS. 13A and 13B depict a valve which is bistable in
operation.
[0079] FIG. 14 depicts a perspective view of a three-dimensional
tilt mirror.
[0080] FIG. 15 illustrates an SEM image of a fabricated mirror of
the design of FIG. 14.
[0081] FIGS. 16A-16C depicts various views of a mirror according to
an embodiment of the invention.
[0082] FIGS. 17A-17C depict various views of a mirror according to
an embodiment of the invention.
[0083] FIGS. 18A-18C depict various views of a mirror according to
an embodiment of the invention.
[0084] FIG. 19A-19C depicts various mirror configurations according
to various embodiments of the invention.
[0085] FIGS. 20A-20B depict perspective views of a mirror design
and a fabricated mirror, respectively, according to an embodiment
of the invention.
[0086] FIG. 21A-21B depict a scanning mirror and an actuation
electrode, respectively, for an embodiment of the invention.
[0087] FIG. 21C depicts another alternative embodiment where
electrode elevation is contoured to approximate, at least in part,
the path of traveled by the mirror.
[0088] FIG. 22 depicts a structure containing a number of
microchannels connecting wells.
[0089] FIG. 23 shows a cross section of a coaxial extrusion die
designed to be fabricated with electrochemical fabrication
technology and which is capable of extruding up to three different
materials.
[0090] FIG. 24A-24C depict samples of extrudates as might be
generated from the extrusion die like that of FIG. 23.
[0091] FIG. 25 shows how a single vacuum manifold can connect all
the vacuum holes in a surface according to an embodiment of the
invention.
[0092] FIGS. 26A and 26B illustrate different probe tip
configurations.
[0093] FIG. 27 illustrates a pressure sensor whose movement is
controlled by a bellows-like structure.
[0094] FIG. 28A-28D depicts various actuators according to an
embodiment of the invention.
[0095] FIGS. 29A and 29B depict perspective view of the actuators
similar to those in FIGS. 28A and 28B.
[0096] FIGS. 30A-30F depict various switches according to different
embodiments of the invention.
[0097] FIGS. 31A-31C depicts various electrode and beam
relationships according to different embodiments of the
invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0098] FIGS. 1A-1G, 2A-2F, and 3A-3C illustrate various features of
Electrochemical Fabrication that are known. Other electrochemical
fabrication techniques are set forth in the '630 patent referenced
above, in the various previously incorporated publications, in
patent applications incorporated herein by reference, still others
may be derived from combinations of various approaches described in
these publications, patents, and applications, or are otherwise
known or ascertainable by those of skill in the art. All of these
techniques may be combined with those of the present invention to
yield enhanced embodiments.
[0099] Some embodiments present miniature sensors or actuators that
may be formed totally or in part using Electrochemical Fabrication
techniques. Some of these devices may be formed monolithically in
an Electrochemical Fabrication process. Some of these devices make
use of applied electric fields to cause motion. Some embodiments
use parallel plate gap closing effects while others use comb drive
type effects. Some devices make use of applied electric fields to
detect motion. A change in distance between capacitor plates
produces a change in capacitance which can be electrically
measured). Devices that rely on electric field properties to cause
or sense motion are sometimes termed "electrostatic devices" even
though the electric fields supplied or detected may not be static.
Electrostatic devices offer several advantages: (1) their use is
simple as it is relatively easy to apply and measure voltages, (2)
relatively simple geometries may be usable, (3) at the distance
scales involved in miniature devices (e.g. meso-scale and
microscale devices) electrostatic forces become significant enough
to move and manipulate mechanisms, (4) electrostatic devices may be
configured for low power consumption, (5) electrostatic devices can
operate quickly, and (6) Electrostatic devices can be shielded from
the influence of external fields while producing little
electromagnetic interference themselves. The designation of devices
as "electrostatic" does not imply that the electric field doesn't
change or that only DC currents are involved, but rather that the
physics of electric fields dominates over the physics of any
induced magnetic fields. In fact, electrostatic devices have been
operated over a large frequency range (e.g. up to several kilohertz
or more).
[0100] Electrostatic devices proposed or developed have typically
suffered from some problems: (1) though electrostatic forces
achieved have been sufficient for some applications, they have been
inadequate for others; (2) high actuation voltages have typically
been necessary, e.g. in excess of 100 volts, and/or (3) some
devices have exhibited unpredictable behavior or stiction which may
be the result of production of unintended electric fields. Some
embodiments of electrostatic actuators and sensors to be discussed
hereafter lessen the severity of some of these problems: (1) by
producing higher forces at lower actuation voltages, and/or (2) by
providing higher capacitance changes at a given displacement for
capacitance sensing, (3) by providing higher conductivity material,
as compared to silicon, which may help reduce unintended charging,
reduce power consumption, and allow operation at higher
frequencies.
[0101] EFAB enables numerous new electrostatic actuator embodiments
that create greater electrostatic force. As greater electrostatic
force typically translates into greater capacitance structures of
these embodiments can be advantageously used in sensor applications
as well.
[0102] Linear electrostatic actuators, such as comb drives,
typically employ some form of parallel plate configuration, in
which the gap spacing between plates is fixed, while the area of
overlap between plates changes during actuation, typically
resulting in a linear motion and a linear relationship between
applied voltage and displacement. The main issues associated with
linear electrostatic actuators actuation force vs. voltage and
total displacement or throw. By far the most widely used linear
electrostatic actuator is the comb drive actuator, in which a
series of interdigitated finger shaped electrodes provide an
attractive force. Comb drive actuators previously proposed or
developed provided a 2D array of comb fingers. The actuation force
may be maximized by increasing the number of fingers, reducing the
gap between the fingers, and increasing the thickness or depth of
the fingers. Comb drives produced by surface micromachining have
gaps of typically 1 or 2 microns and thickness of 2 microns in
large arrays of dozens or even hundreds of comb fingers. In order
to further increase the force, high-aspect ratio processes have
been used to create very deep comb fingers. For example, DRIE-based
comb fingers greater than 100 microns in thickness have been
created. Limitations of conventional high-aspect ratio processing
generally have required an increased comb gap at greater etch
depths which have somewhat reduced the advantages of using high
aspect ratio structures. These high aspect ratio comb drive
actuators are essentially tall, extruded 2D comb drive arrays.
[0103] According to certain embodiments of the present invention,
3D arrays of comb drives containing many more combs than possible
in a 2D array may be fabricated. Furthermore, according to some of
these embodiments, it is possible to produces such actuators
without a gap width to structure thickness dependence as thickness
may be increased by simply adding more layers. In these some of
these embodiments (to be discussed further hereafter), more combs
are created in a smaller cross-sectional area thus allowing greater
forces to be generated at lower voltages. Alternatively, or
additionally, supporting spring and framework can be designed to
allow greater displacement and greater stability at higher
operating voltages. In still other embodiments such actuators may
be combined with dielectric stops and the like to inhibit shorting.
In still further embodiments it is possible to configure actuators
to provide rotary motions as opposed to linear motion. In still
further embodiments comb drives may be configured to provided
multi-directional motion.
[0104] Electrostatic actuators may also be designed using parallel
plates that create a driving force that attracts selected plates to
one another thereby causing a motion that changes a gap between
adjacent plates as they move. Conversely, sensors may be formed
that take advantage of the change in capacitance that results from
separation of the plates changing (pressure sensors and
accelerometers). These actuators typically produce higher forces
than to comb drives but are nonlinear in their operation.
Typically, these actuators are implemented by placing an electrode
underneath a structure, the electrode then pulls the structure
downwards. Most tilting mirror devices use some version of this
principal.
[0105] Some embodiments of the present benefit from a greater
flexibility in arrangement of the gap closing electrodes that may
be achieved via three-dimensional structuring of the actuator that
is allowed by a true multi-layer fabrication process (e.g. by the
ability to use more than 5 to 10 layers). For example, in some
embodiments electrodes may be placed above and below a device for
bi-directional actuation. In other embodiments a stationary
actuator can act in the middle of two moving members. In still
other embodiments enhanced sensor may be provided such as 2-axis
and 3-axis accelerometers. In still other embodiments, stacking of
electrode plates may be used to obtain a greater measure of change
for a given displacement as opposed to implementations where single
pair of plates are used in detecting a displacement.
[0106] With gap closing actuators, the force is generally
approximately proportional to the square of the gap distance. This
can be a problem when a large range of motion is required. In the
state-of-the-art, the electrodes are placed at a distance from the
moving member, so that the moving member does not touch the
electrode throughout its full range of motion. Unfortunately, this
often requires the electrode to be placed at a substantial distance
from the moving member, which drastically reduces the available
force. It then becomes difficult to initiate motion in the moving
member. As a result, tilt mirror devices for example typically
require large operating voltages due to the large distance between
the mirror and electrode. Furthermore, this conventional approach
results in a very nonlinear actuator behavior, requiring use of
complex control schemes to compensate for the increase in force as
the gap closes. In fact as it is typical for the spring force to
increase only linearly with displacement, a maximum point in
displacement can occur where the attractive force exceeds the
return force and snapping closure occurs.
[0107] In some embodiments of the present invention, electrode and
or moving member configuration is modified so that the actuating
electrode is close to the moving member but does not intersect the
path of motion. In some embodiments the electrode is supplied with
a stairstep configuration (e.g. the electrode is formed from a
stack of layers whose structure approximates a curve under which a
cantilever beam will bend. It is believed that such a configuration
may provide a substantial increase in force (or allow a significant
reduction in driving voltage) while maintaining a desired extent of
motion. Alternatively, the stiffness of the return springs could be
increased without an increase in drive voltage to change the
mechanical resonance frequency of the member. In other embodiments
the actuation electrode for a cantilever beam may not be positioned
so that it is only located, for example, in a plane below the beam
but instead it may be configured to be both below and to the sides
(or at least approaching the sides) of the beam such that the
distance between the beam and portions of electrode is dramatically
decreased while still allowing full motion of the beam. In still
other embodiments, the beam may be made to move in more than one
direction using multiple electrodes. In other embodiments, the
electrodes may be both underneath a moving member and located to an
elevated position beyond the end of the moving member. For example,
the electrodes that control the multi-directional movement of a
scanning mirror may be located below their respective portions of
the scanning mirror as well as at an elevated position beyond the
lateral extents of the moving mirror surface. In still further
embodiments, the electrodes may be partially contoured to bring its
surface closer to a moving member in such away as not to hinder the
required motion while the moving member itself includes surface
level modifications (e.g. deviates from a planar configuration) to
bring portions of its surface closer to that of the electrode. In
still further embodiments, the electrode may contain no surface
level modifications (e.g. it may remain planar) while the moving
member contains surface level modifications.
[0108] In still further embodiments, closing gap actuators may be
stacked in series to increase the total throw of the actuator. An
example is shown on pages 56 and 57. A 3D volume of such electrodes
could be used to construct an actuator `fabric` with high
displacement and force.
[0109] Multiple electrostatic actuators can be configured to
achieve complex functionality, such as for use as multi-axis
component alignment structures. In some embodiments, required
electrical traces may be formed in an EFAB process on a dielectric
along with the formation of the rest of the devices or structures.
In other embodiments it is also possible with EFAB to embed the
conductive lines inside an insulating matrix as part of the
composition of the supporting structural member. This allows
multiple signals to be routed within a mechanical structure with
minimal impact on the design and performance of the structure.
[0110] Electrostatic micromotors may also be made practical
according to some embodiments of the invention by allowing
formation of motors with both top drive and bottom drive electrodes
as opposed to the top drive or side drive electrodes previously
proposed.
[0111] FIG. 4 illustrates a pressure sensor according to a first
embodiment. This pressure sensor includes a plurality of stacked
capacitor plates that may by used to enhance the sensitivity of any
displacement caused by a pressure differential. The pressure sensor
of the present embodiment includes a base plate 102 through which
conductive leads 104 and 106 extend. Conductive lead 106 connects
to walls 108 and flexible lid member 112 when a pressure P is
exerted on the outside lid member 112 which exceeds a pressure P
inside a chamber 114 formed by base 102 walls 108 and lid 112, a
downward deflection of lid 112 occurs which causes a deflection of
capacitive plates 116(a), 116(b) and 116(c) relative to capacitive
plates 118(a), 118(b), and 118(c). This deflection causes a change
in the capacitance of the capacitor that is formed by set of plates
116(a)-116(c) and 118(a)-118(c). This change in capacitance can be
detected and correlated to a pressure differential. Due to the
existence of multiple capacitor plates, the sensitivity of the
sensor may be increased over that of a single set of or level of
plates.
[0112] In alternative embodiments more then three pairs of
capacitor plates may be used. In some embodiments a single pair of
capacitor plates may suffice while in other embodiments many pairs
of capacitor plates might be appropriate. In some embodiments the
hermetic sealing techniques set forth in U.S. Patent Application
60/379,182, filed May 7, 2002 and in U.S. Patent Application
60/430,809, filed Dec. 3, 2002 may be used to form pressure
sensors. In some alternative embodiments conductive leads 106 and
104 may extend from a wall of the sensor as opposed to through the
base. In such alternative embodiments, if the walls form part of
the conductive path that lead to a set of the capacitor plates,
then the conductive lead for the other set of plates may be
separated from the wall by a dielectric material where the
dielectric material may be added to the structure after its
formation or may be added to the structure during its formation
such as during formation on a layer-by-layer basis by
electrochemical fabrication. In still other embodiments the walls
and the exposed surface of lid 112 may be of the dielectric
material or a dielectric coated conductor. In still other
embodiments fixed capacitor plates 118(a)-118(c) may be connected
to a portion of the walls as opposed to being mounted on the base.
In some embodiments the sensors may detect, for example, pressure,
displacement, or function as enhanced-sensitivity accelerometers
(assuming the lid 112 doesn't effective displacement significantly
and that moveable plates 116(a)-116(c) have sufficient mass).
[0113] A second embodiment is depicted in FIG. 5. As in the first
embodiment, FIG. 5 depicts a side view relative to a plurality of
layers from which the structure was formed. FIG. 5 depicts an
actuator as opposed to the sensor of FIG. 4. The actuator consists
of a shaft 122 that is connected to spring-like return arms 124 and
126 where the return arms are mounted in a fixed position at
location 128 and 132. Connected to shaft 122 are capacitor plates
136(a)-136(c). A second set of capacitor plates 138(a)-138(c) are
mounted to a frame (not shown) which may be the same frame to which
portions 128 and 132 of return arms are directly or indirectly
mounted. As a voltage V is applied between the two sets of
capacitor plates, shaft 122 is displaced. Since the total force
associated with the displacement of shaft 122 is related to the
capacitance and since the capacitance is related to the effective
area of the plates, by using multiple sets of plates a higher
driving force can be obtained for a given cross-sectional area of
individual plates. In some embodiments the actuator of FIG. 5 may
be included in a housing in much the same manner as illustrated in
FIG. 4, with the possible exception of an opening in a base or a
lid such that the shaft may be coupled to an external element that
is to be actuated. In alternative embodiments coupling between the
shaft and an external component may occur via a non-physical link
such as, for example, via capacitive, inductive, or magnetic
coupling. In some embodiments a single pair of capacitive plates
might suffice while in other embodiments many more sets of
capacitor plates might be used. In still other embodiments sets of
capacitive plates might be connected to different shafts and each
of the shafts linked to a primary shaft such that the total force
is increased still further. In some embodiments hundreds or even
thousands of sets of plates may be used.
[0114] In the first and second embodiments the side views
illustrated do not depict cross-sectional dimensions of the plates
(along the dimension extending into the page). The plates may take
on rectangular dimensions or circular dimensions or any other
configuration that is appropriate to the constraints of a given
application. The embodiment of FIG. 5 may be used to control, for
example, a shutter mechanism in an optical application or a worm
drive in an application where extended motion is required.
[0115] In some embodiments, the capacitor plates need not be planar
and when used herein unless otherwise indicated indications of
"parallel to", or "perpendicular to" capacitor plates should be
interpreted as relative to a plane of a relevant portion of the
surface of a plate or plates.
[0116] A third embodiment of the invention is depicted in FIGS.
6A-6C. FIG. 6A depicts a perspective view of the moving portion of
an actuator while FIG. 6B depicts an expanded view of a portion of
the structure of FIG. 6A such that individual capacitor plates can
be seen in several of the stacks. FIG. 6C depicts a top view of
both the moving elements and the fixed elements of the actuator of
FIGS. 6A and 6B. The moving elements of actuator 6(a) include a
plurality of stacks 142a-142r of capacitor plates where each stack
itself includes a plurality of capacitor plates as illustrated in
FIG. 6B as 142a(1), 142a(2), 142a(3), etc. The moving elements also
include a shaft 144 and columns 146 that connect all of the
capacitor plates into a single structure. Shaft 144 is supported by
spring-like elements 148 and 150 which in turn have one end 152 and
154 connected to columns 156 and 158 that extend to a frame (not
shown). For clarity of presentation FIGS. 6A and 6B do not depict
the plurality of fixed capacitor plates that are interleaved
partially between the moving capacitor plates 142a(1)-142a(3), etc
and that would be supported by an appropriate structure relative to
the support columns 156 and 158. The upper layer of movable
capacitor plates 142a(1)-142r(1) are shown in FIG. 6C along with
spring-like return arms 148 and 150 and shaft 144. FIG. 6C also
depicts the upper level of fixed capacitor plates 162a(1)-162r(1).
Fixed capacitor plates 162a(1)-162r(1) are connected to a frame
(not shown) via connecting element 164. As a voltage is applied
between the moving plates and the fixed plates, the plates are
drawn into a tighter overlapping position thereby making shaft 144
move in direction 166. As with the embodiments of FIGS. 4 and 5 the
embodiments of FIG. 6 can take on numerous alternative
configurations. For example the actuator of FIG. 6A-6C may by
enclosed in a housing. In some embodiments, the return elements may
take forms different from those shown. In other embodiments, for
example, the number of stacks of capacitor plates may be reduced to
one or extended to many times the number depicted and likewise the
number of capacitor plates on any given stack may be decreased to
one or increased well beyond the number illustrated. In still other
embodiments instead of driving the structure of FIGS. 6A-6C by
applying a voltage of the desired magnitude, the structure may be
used as a sensor whereas a displacement of shaft 144 may give rise
to a change in capacitance which can in turn give rise to a
detectable electrical signal which can be correlated to the
displaced amount.
[0117] A fourth embodiment of the present invention provides a
linear variable differential transformer or LVDT which may be
monolithically produced by electrochemical fabrication. As
indicated in FIG. 7, the LVDT may consist of a primary transformer
coil 180 and two secondary transformer coils 182a and 182b.
Additionally, an armature of magnetically permeable material is
included that may move back and forth such that different amounts
of the armature may be located in secondary coils 182a or 182b.
Armature 184 may have a non-magnetically permeable extension
extending out of one or both ends of the secondary coils as
indicated by reference numbers 186a and 186b. In use, the LVDT may
be supplied with a voltage V1 on primary coils 180 and a voltage
difference V2 between the two secondary coils may be detected, to
yield a value which can be related to the position of armature 184.
Armature 184 is connected via elements 186a or 186b to a structure
whose position is to be measured. The detected voltage V2 may be
used to determine the position of the desired structure. Using
electrochemical fabrication windings of coils 180, 182a and 182b
may be formed out of a first material such as copper while armature
184 may be formed out of a material such a permalloy. Elements 186a
and 186b may be formed out of a suitable conductive or dielectric
materials. An insulating material may be formed between the
conductive elements 180, 182a, and 182b. Each of these materials as
well as a sacrificial material (and any other needed materials) may
be deposited (e.g. via electrochemical fabrication) on a
layer-by-layer basis until a plurality of layers have been
deposited to complete formation of the structure. As with the other
embodiments numerous alternatives are possible. For example, the
openings through coils 180, 182a, and 182b may be circular or
rectangular in shape while armature 184 may take on a corresponding
shape or other shape. The sensor of FIG. 7 may also be formed in a
protective housing that may also be formed via electrochemical
fabrication.
[0118] In some embodiments of the present invention the structures
and devices formed may have features as small as a micron, or
potentially even smaller, or as large as 10s or even 100s of
microns or even larger.
[0119] In some alternative embodiments, the sensors and actuators
may use alternatively shaped electrodes and actuation plates as
discussed herein above and as illustrated in some embodiments to be
discussed herein after.
[0120] Another embodiment of the instant invention is depicted in
FIG. 8A-8D. This embodiment is directed to a single pole double
through SPDT switch 202 whose moveable contact arm 204 is connected
to a substrate via pedestal 206. A plurality of plates
208(a)-208(d) via vertical extending are connected element to 212.
The moving member ends with contact element 214(a) and 214(b)
located between two poles 216(a) and 216(b). These poles are
supported by arms 218(a) and 218(b), respectively, which in turn
are connected to a base by pedestals 222(a) and 222(b)
respectively. The embodiment includes additional actuator plates. A
first set of which includes plates 224(a)-224(d) that are used to
pull moving member 204 upward and thus are used to cause contact
element 214(a) to close with contact element 216(a). Another set of
actuation plates 228(a)-228(d) are used to pull moving member 204
downward and thus to cause contact element 214(b) to close with
pole 216(b). Plates 228(a)-228(d) are supported by vertical element
234 while plates 244(a)-224(d) are supported by vertical element
232. A switch of this type may be used to switch a signal between 3
states: (1) The open state--no contact between 214(b) and 216(b)
and no contact between 214(a) and 216(a), (2) Closed state No. 1
where a signal is carried between elements 206 and 222(b) via
contact between 214(b) and 216(b), (3) Closed state No. 2 where a
signal is carried between elements 206 and 222(a) via contact
between elements 214(a) and 216(a). While FIG. 8A depicts a side
view, FIG. 8B depicts a back view and FIGS. 8C and 8D depict
perspective views.
[0121] In alternative embodiments many variations of the design are
possible. For example different numbers or sizes of plates may be
used, different element dimensions are possible, the contact
materials of elements 214(a), 214(b), 216(a) and 216(b) maybe
different from the material of moving member 204 and arms 218(a)
and 218(b). In still other embodiments, actuation voltages may be
isolated from signals via independent lines that are separated by
dielectrics. In still further embodiments contact elements 216(a)
and 216(b) need not be located at the ends of flexible arm elements
but instead may be rigidly mounted on pedestals or the like.
[0122] As illustrated in the FIGS. 8A-8D the elements of the switch
are elevated above the substrate to reduce capacitance. In
alternative embodiments, the switch elements may be mounted to a
substrate. Multiple switch configurations are possible, including
multipole and multi throw switches. Multiple switches may be
configured in parallel for greater current handling and
reliability, or in series. The contact geometry can be modified. A
wide range of actuators may be used. Many different suitable
electrostatic actuator designs are possible. In other embodiments,
actuation may be implemented in other ways including magnetic,
thermal, pneumatic, bimetallic, acoustic, piezoelectric schemes.
These switches may operate at DC or RF frequencies. Switches which
do not require physical contact, such as those based on capacitive
coupling whether in series or shunt configuration for example, are
possible. Stops may be used to prevent shorting in the case of
capacitive switches, or spring brakes may be used to reduce the
impact force immediately prior to closure to improve reliability
and eliminate bounce.
[0123] Another embodiment of the invention is illustrated on FIG.
9A. FIG. 9A illustrates the mechanical portion of an accelerometer
which includes a proof mass 262 supported by eight arms, four of
which are labeled with reference numeral 264(a) and three of which
are labeled 264(b) while the eighth arm is invisible in this
perspective view. Each pair of arms in connected to a support
column 266 which in turn rests on a base not shown. Below the proof
mass a plate 268 is shown, the proof mass and the plate 268
function as a capacitor of variable capacitance. The capacitance
varies as accelerations in direction 272 cause relative
displacements of the proof mass and the plate 268. In the
illustrated design spring supports 264(a) and 264(b) are located
above and below the center of mass of proof mass 262. In
alternative embodiments a single set of spring supports may have
been located at the level of the center of the mass or at a
different level. In still other embodiments a different number of
spring supports are possible. In still other embodiments the
capacitance plate 268 may be suspended above a substrate so as to
reduce parasitic capacitance. And in still other embodiments
shorting between the plate 268 and proof mass 262 may be avoided
completely or at least minimized by including posts, tabs, stops or
other motion limiters that are made of dielectric materials and
located between the plate and the mask. Alternatively, motion
limiters may be made of conductive material that is mounted to the
substrate and that extends between the mass and the plate but does
not make electrical contact with the plate.
[0124] FIG. 9B illustrates a three dimensional version of an
accelerometer that can be fabricated using electrochemical
fabrication. In this embodiment, posts 282 and capacitor plates
284(a) and (b) and 286(a) and (b) as well as a plate located above
proof mass 288 and below proof mass 288 (plates not shown) are
fixedly to a substrate. Springs 292 allow the proof mass to move in
the vertical direction when an acceleration occurs in that
direction. Such movement changes the capacitance between the proof
mass and the plates thus allowing detection of the vertical
acceleration. Springs 294 allow the proof mass to move in the X
direction (it is noted that springs 292 are inflexible in that
direction). The movement of the proof mass in the X direction can
change the capacitance between capacitor plates 286(a) and 286(b)
and frame elements 296(a) and 296(b), respectively allowing the
capacitance to change, thus allowing detection of acceleration in
the X direction. Similarly acceleration in the Y direction can be
detected by changing capacitance between frame elements 302(a) and
302(b) and capacitor plates 284(a) and 284(b), respectively. This
movement is allowed by springs 304. It should be noted that springs
292 and 294 are substantially inflexible in the Y direction. The
capacitance change between elements 302(a) and 284(a) and 302(b)
and 284(b) can be detected thus allowing detection of acceleration
in the Y direction. In other embodiments other accelerometer
configurations are possible.
[0125] FIG. 10 illustrates another embodiment of the present
invention where a check valve is provided. The figure illustrates a
perspective view of one half of the check valve (the front half of
the check valve being removed so that the internal passages
extending through the valve can be seen). The valve includes valve
plate 312 located over an opening 314 which is at the end of
passages 316(a), 316(b) and 316(c). Valve plate 312 is supported by
a corrugated support bar or spring which allows the valve plate or
diaphragm to seal against the valve seat that surrounds opening
314. Openings 316(a)-316(c) allow three different fluids to enter
channel 318 and mix before exiting opening 314 when valve plate 312
is unseated due to pressure in chamber 318 exceeding the pressure
above plate 312. In FIG. 10 the valve plate is shown separated from
the seat surrounding opening 314 for illustrative purposes. In some
embodiments the valve may be normally closed so that it is opened
by an excess pressure in chamber 318. In other embodiments the
valve may be normally open where some elevated pressure above plate
312 is required to close the valve.
[0126] Though a check valve is illustrated in FIG. 10, a wide range
of microfluidic devices are possible, including various pumps and
valves. As an example of another fluid control device, FIG. 11,
depicts a pressure controlled bellows valve that can be made using
electrochemical fabrication. Application of positive and negative
relative hydraulic or pneumatic pressure to the bellows 332 via
channel 336 can cause the bellows 332 to seal against valve seat
334 to block fluid flow between chamber 338 and channel 342
[0127] A further example of a manufacturing process for a valve is
illustrated in FIGS. 12A-12F. The valve illustrated in these
figures is capable of proportional flow. In FIG. 12A, the valve has
been fabricated partway using an electrochemical fabrication
process of selective depositions, blanket depositions and
planarization operations. FIG. 12A depicts the block of material as
including a selective patterning of a sacrificial material 402 and
a structural material 404. The embedded valve is shown as having a
poppet 406, a valve seat 408, an inlet channel 412 and an outlet
channel 414. FIG. 12B depicts that a portion of the sacrificial
material 402 has been etched away using the top layer of structural
material 404 as a temporary masking layer. In FIG. 12C the
temporary masking layer has been planarized away and a layer of
shape memory alloy 416 (SMA, e.g., nickel-titanium) has been
deposited (e.g., by removing the substrate from the EFAB system and
placing in a sputtering chamber). In FIG. 1D, the structure has
been planarized, creating a layer that contains structural material
404, sacrificial material 402, and SMA 416. The pattern of the SMA
material is defined by the apertures that were in the temporary
masking layer and the resulting partial etch of sacrificial
material illustrated in FIG. 12B and was selected to form bendable
supports for the poppet 406 of structural material. It should be
noted that these supports only occupy a portion of the gap between
poppet and surrounding material (they do not form a continuous
membrane). One result of this is that the upper and lower volumes
of sacrificial material are interconnected to allow for etching of
the upper volume. FIG. 12E illustrate that additional
electrochemical fabrication steps have been performed to form a cap
of structural material. Finally, in FIG. 12F the sacrificial
material has been etched, forming fluid channels and cavities and
freeing the SMA supports to move the poppet against the valve seat.
The valve may be prepared for use by applying a force to the poppet
(e.g., by deforming the cap so as to provide a springy membrane
that pushes the poppet down) so as to preload the poppet against
the valve seat, causing the valve to close and the SMA material to
be deformed from its as-fabricated state. By heating the SMA
supports (e.g., by heating the valve overall, or passing current
through the SMA material), the SMA material will return to its
original state, opening the valve. Proportional action may be
obtained by controlling the amount of heating: a small amount of
heating will open the valve only slightly, while a large amount
will open it fully. It is noted that the inlet and outlet ports can
be reversed from what is shown. In other embodiments shape memory
alloys may be used in the formation cause biasing of various types
of components. In still other embodiments the halting of
electrochemical fabrication operations may be performed for the
purpose of performing other operations that etching and SMA
deposition.
[0128] In other embodiments, other valves of similar design can be
achieved by replacing the SMA supports in the valve described above
with other actuators including thermal actuators (e.g., thermal
bimorph, heatuator (a loop with segments having non-uniform
cross-sectional area), piezoelectric actuators, and so forth.
[0129] FIGS. 13A and 13B depict a valve which is bistable in
operation: this latching behavior minimizes current consumption.
The valve consists of a poppet 422 which is supported by a membrane
424 which is in compression and is stable either when convex (bent
upwards) or concave (bent downwards). Corrugations in the membrane
allow it to contract slightly when transitioning from convex to
concave. Also attached to the poppet is a permanent magnet 426
which may be fabricated as part of an electrochemical fabrication
process. The permanent magnet preferably forms the core of a
solenoid with multiple windings 428 (e.g. of copper). These
windings may be embedded in dielectric material 432 to provide
mechanical stabilization and electrical isolation. It should be
noted that the membrane also serves to guide the motion of the
magnet. When current is applied to the coil in one polarity, the
magnet will be drawn downwards as shown in FIG. 2B, pulling the
poppet away from the valve seat to open the valve, and also
deforming the membrane so that it is concave. At this time, current
can be removed and the valve will remain open. When it is desired
to close the valve, current of opposite polarity is applied to the
coil, causing the magnet to be repelled from the coil. This forces
the membrane to deform into its convex configuration, pushing the
poppet against the valve seat. In alternative embodiments the inlet
434 and outlet ports 436 can be reversed from what is shown. Also,
the diaphragm need not be continuous so long as it is acceptable to
immerse the components below the diaphragm in the fluid controlled
by the valve, and so long as the additional fluid force acting to
hold the valve closed in the design shown can be overcome by the
force produced by the magnet and coil.
[0130] FIG. 14 depicts a perspective view of a three-dimensional
tilt mirror. The mirror assembly includes two support structures
452 which contact the substrate and four electrodes 454(a)-454(d)
that also rest upon a substrate. The mirror 456 is supported by
springs 458(a) and 458(b), by ring 462, and by springs 464(a) and
464(b) that allow rotation of the mirror and a direction
substantially perpendicular to that allowed by springs 458(a) and
458(b). To cause tilting of the mirror a potential can be applied
to one of blocks 452 and one or more of electrodes 454(a)-454(d).
In some embodiments springs 458(a), 458(b), 464(a), and 464(b)
maybe of the same material as the mirror surface. In some
embodiments the mirror maybe thicker than the support springs. In
still other embodiments the mirror may have a ribbed structure,
thereby strengthening it while still maintaining a relatively low
moment of inertia. Similarly the outer ring 462 may be thicker than
the support springs. In still other embodiments, the drive
electrodes may be suspended above the substrate to reduce parasitic
capacitance while in other embodiments the springs of the mirror
may be folded out of the plane of the mirror to decrease the
horizontal extents of the monolithic mirror assembly. An SEM image
of a fabricated mirror of the design of FIG. 14 is illustrated in
FIG. 15.
[0131] FIG. 16A-16C illustrate an alternative embodiment of mirror
support springs. FIG. 16A depicts a top view showing a mirror 472
located above two support springs 472. FIG. 16B illustrates a
bottom view of the mirror 472 showing that support springs 474
contact a pedestal 476, which is located at the center of the
mirror. FIG. 16C shows a side view which indicates that springs 474
are spaced out of the plane of mirror 472. As a result of this
configuration less spring extent beyond the edge of mirror 472 is
needed to allow a particular spring constant to be obtained. As
such, an embodiment of this type can allow the horizontal extents
of a mirror assembly to be reduced and thus an array of mirrors to
be placed closer to one another.
[0132] FIGS. 17A-17C depict another alternative embodiment for
reducing the horizontal extents of the mirror assembly. As with
FIGS. 16A-16C these figures only illustrate the springs and
connections associated with a single axis of motion. It is to be
understood that the other axis of motion may be obtained by
appropriate design extension. FIG. 17A depicts a top view of a
mirror where the springs and other rotational components are hidden
beneath its surface. FIG. 17B depicts a bottom view of the mirror,
where an outer ring attached to the bottom of the mirror can be
seen with spring elements for 482 shown connected to the ring 484
and to a center piece 486. FIG. 17C indicates that springs 482 are
separated from mirror 488 by their contact with ring element 484.
Spring elements also connect to center post 486 which may be held
in fixed position and the mirror may be made to rotate about the
axis of springs 482.
[0133] Another alternative mirror embodiment is illustrated in
FIGS. 18A-18C which depict side views of a mirror 494 spaced above
electrodes 496(a) and 496(b). At the center of mirror 494 a spring
element 498 is illustrated which allows pivoting in the directions
of electrodes 496(a) and 496(b). FIG. 18B illustrates the mirror
tilted towards electrode 496(b) while FIG. 18C depicts mirror
tilted toward electrode 496(a). Instead of using a planer electrode
as is typical, the electrodes of this embodiment have a contoured
shape which allows them to be positioned closer to the mirror
surface to decrease the voltage required to cause it to rotate
while also maintaining a position that does not hinder the movement
of the mirror.
[0134] FIGS. 19A-19C depict further alternative scanner mirror
embodiments. In FIG. 19A scanning mirror 502 is positioned above
electrodes 504(a) and 504(b) and a spring element 506 is located at
the center of mirror 502 this allows the mirror to rotate toward
either electrode 504(a) or 504(b). The distinguishing feature of
this embodiment as compared to the embodiment of FIGS. 18A-18C is
that only the outer extents of the mirror are positioned at an
elevated level while the portions of the electrodes approaching the
center of the mirror remain flat. In FIG. 19B, mirror 512 is
positioned above electrodes 514(a) and 514(b). Spring element 516
allows the mirror to pivot toward the electrodes which in this case
have an elevated configuration toward the center of the mirror
without any electrode elevation near the sides of the mirror.
Additionally in this embodiment stops of dielectric material 518
are located on electrodes 514(a) and 514(b) so as to inhibit mirror
512 from contacting the electrodes. FIG. 19C, is similar to 19B
with the exception that dielectric stops 528 are located on the
bottom of mirror 522 as opposed to on electrodes 524(a) and
524(b).
[0135] Another alternative embodiment is depicted in FIGS. 20A and
20B. FIG. 20A depicts a perspective view of a mirror 542 positioned
above electrodes 544(a) and 544(b). The electrodes of this
embodiment have a similar configuration to those of FIGS. 18A-18C.
In the examples of FIGS. 18A-20A, the electrodes are shown as
having smoothed faced slanted surfaces. Such smoothness is
obtainable in some embodiments potentially by performing an
additional deposition operation after formation of all layers of a
structure and release of the structure from a sacrificial material.
However in other embodiments the electrodes may remain with slanted
surfaces with a stair step configuration as the height of the
electrodes would be formed from a series of layers stacked one upon
the other. FIG. 20B depicts an SEM image of a fabricated mirror of
the configuration shown in FIG. 20A. The stair step nature of the
electrodes can be seen in this figure.
[0136] Another alternative scanning mirror embodiment is
illustrated in FIGS. 21A-21C. FIG. 21A depicts a scanning mirror,
very similar to the scanning mirror of FIG. 14 with the difference
that electrodes 554(a)-554(d) have an elevated configuration as
opposed to the flat configuration of FIG. 14. FIG. 21B depicts
layer contour levels of electrode 554(c), where the center portion
556 of electrode 554(c) is at the lowest level while portion 558 is
at an elevated level with regions between 556 and 558 at
intermediate levels. Similarly 562 is at an elevated level with
portions between 556 and 562 at intermediate levels. FIG. 21C
depicts another alternative embodiment where electrode elevation is
contoured to approximate, at least in part, the path of travel by
the mirror. In FIG. 21C the electrodes have a curved configuration
while in FIGS. 21A and 21B had a square configuration.
[0137] Many additional alternative mirror embodiments are possible.
In some such alternatives densely packed fields of components that
include mirrors or other relatively high voltage components or
components that carry high frequency signals may benefit from the
fabrication of walls of conductive material around their perimeter.
These walls of conducted material may be grounded, thereby helping
to shield nearby components from negative influenced associated
with the electrical activity of other components. Similarly such
walls may help shield the other components from the electrical
activity of the surrounded components.
[0138] Another embodiment of the present invention is illustrated
in Fabricated device of FIG. 22. FIG. 22 depicts a structure
containing a number of microchannels connecting wells. Microfluidic
systems often require complex networks of wells and channels for
their operation. Such channels can be used to make multilayer
fluidic networks which include channels running in different
directions, transitioning between different heights, wells,
integrated valves, pumps, mixers, connectors and couplings, and so
on.
[0139] Electrochemical fabrication technology can be used to
fabricate tooling to enable a wide variety of industrial processes
on a small scale. Examples of such tooling are as follows:
[0140] Electrical Discharge Machining (EDM). Electrodes suitable
for EDM of various materials (including tool steels) can be made
with electrochemical fabrication technology, particularly from
copper and other electrodepositable elements and alloys that can be
used as structural material in electrochemical fabrication
technology. Materials with low erosion properties during EDM are
preferred. Tooling for EDM grinding and related processes can also
be created by co-depositing abrasive particles (e.g., diamond,
silicon carbide, boron carbide, aluminum oxide) along with
metal.
[0141] Electrochemical Machining (ECM). Tooling suitable for ECM,
electrochemical deburring, shaped tube electrolytic machining, and
related means of processing a variety of materials can be made with
EFAB technology. Tooling for electrochemical grinding and similar
processes can also be created by co-depositing abrasive particles
(e.g., diamond, silicon carbide, boron carbide, aluminum oxide)
along with metal.
[0142] Electroplating. Anodes with special shapes intended to
control current distribution during plating, enhance plating within
a cavity, and so forth may be made with electrochemical fabrication
technology, for example, from copper, nickel, and platinum.
[0143] Ultrasonic machining. Tooling for ultrasonic machining of
such materials as carbides, ceramics, glass, and metals including
stainless steel can be made with electrochemical fabrication
technology. Tool life can be improved by co-depositing abrasive
particles (e.g., diamond, silicon carbide, boron carbide, aluminum
oxide) along with metal when fabricating the tool.
[0144] Injection and other molding. Tooling for injection,
compression, and transfer molding of components from polymers,
mixtures of polymers and metal (to fabricate metal injection
molding preforms via `metal injection molding`) or of polymers and
ceramic (to fabricate ceramic components via `ceramic injection
molding`) can be made with EFAB technology. Tooling can consist of
multiple elements which when combined form a cavity into which
material is introduced.
[0145] Blow and rotational molding. Tooling for blow molding and
rotational molding can be made with electrochemical fabrication
technology. Tooling can consist of multiple elements which when
combined form a cavity into which material is introduced.
[0146] Extrusion molding. Dies for extruding polymers, metals,
polymer/metal and polymer/ceramic mixtures (in which the polymer is
later removed and the metal or ceramic is sintered) can be made
with electrochemical fabrication technology.
Spinnerets--essentially extrusion dies for polymers used in the
fabrication of synthetic fiber--can similarly be fabricated. Due to
electrochemical fabrication technology's 3-dimensional nature,
semistreamlined and fully streamlined production dies can be
created, in which the die geometry is curved away from the extruded
structure on the exit side of the die. Dies designed to produce
hollow extrusions such as tubing and multi-lumen catheters for
medical applications--both featuring unusually small diameters--can
be produced.
[0147] Of particular interest is the fabrication of extrusion dies
capable of extruding multiple materials simultaneously to form a
composite structure. FIG. 23 shows a cross section of a coaxial
extrusion die designed to be fabricated with electrochemical
fabrication technology and which is capable of extruding up to
three different materials to form a coaxial composite extrudate
such as that in FIG. 24A. The design can be extended to more than
three materials. In FIG. 23, material is supplied through three
separate inlets; these can be on any desired face of the die. The
edges on the exit side of the die are preferably rounded to provide
streamlining. The inner dividing wall (which separates the center
and inner material) may be recessed below the outer dividing wall
so as to allow the center and inner materials to contact and fuse
while the center material is still supported by the outermost wall.
Similarly, the outer dividing wall (which separates the outer and
center material) may be recessed below the outermost wall so as to
allow the outer and center materials to contact and fuse while the
outer material is still supported by the outermost wall. Other
configurations of extrusion dies for multiple materials can, as
shown in FIG. 24B, produce extrudates in which two or more
materials are surrounded by a single material, or which combine the
geometries of the extrudates in both FIGS. 24A and 24B, as shown in
FIG. 24C.
[0148] Thermoforming. Tooling for thermoforming of materials such
as thermoplastics can be made with electrochemical fabrication
technology. Vacuum applied through apertures in the forming surface
of the tool (FIG. 25) or air pressure applied to the opposite side
of the sheet of material to be formed, or both, can be used to form
the sheet over the shape of the tool. The tool in FIG. 25 shows how
a single vacuum manifold can connect all the vacuum holes in the
surface, and also illustrates flaring of the vacuum holes inwards
to enlarge them and promote etching of sacrificial material. Such
tooling can also be used to form ductile material supplied in thin
sheets, with or without heating or the use of vacuum or
pressure.
[0149] Die casting and permanent mold casting. Tooling for die
casting and permanent mold casting of metals, particularly those
with relatively low melting points (aluminum, magnesium, zinc, and
of course, indium, tin, Cerro metals, and solder) can be made using
electrochemical fabrication technology. Tooling can consist of
multiple elements which when combined form a cavity into which
material is introduced.
[0150] Metal forming. Tooling for drop forging and impact
extrusion, progressive die drawing, progressive roll forming,
stretch-draw forming, tube bending, tube and wire drawing, deep
drawing, and brake forming can be made with electrochemical
fabrication technology.
[0151] Powder metal and ceramic die pressing. Tooling for
consolidating metal and ceramic powders into preforms through
pressure and--optionally--heat, prior to sintering can be made with
electrochemical fabrication technology.
[0152] Machining. Tooling for broaching and fine blanking; gear
hobbing and gear shaping; lancing, shearing, and bending; nibbling
and notching; slitting; and punching, perforating and blanking can
be made with electrochemical fabrication technology. Taps and dies
for threading; drills, mills, files, lathe tools (e.g., for
turning, facing, and boring); and routing, shaping, and planing
tools can also be made with electrochemical fabrication
technology.
[0153] Abrasive machining. Tooling for grinding, electrochemical
grinding, EDM grinding (as already mentioned), and honing can be
produced with EFAB technology. In addition, tooling for orbital
grinding (e.g., of graphite, but also of much harder materials) can
be fabricated in this way. Dicing saws for cutting semiconductor,
ceramic, and glass wafers can also be fabricated. All such tooling,
which relies on an abrasive action, can be made by co-depositing
abrasive particles (e.g., diamond, silicon carbide, boron carbide,
aluminum oxide) along with metal.
[0154] The hardness and wear resistance of all of the above tooling
may be made increased by co-depositing particles (e.g., diamond,
silicon carbide, boron carbide, aluminum oxide) along with
electrochemically-deposited metal. Alternatively, spray metal
deposition may be used to blanket deposit tool steel and other
structural materials desirable for tooling applications as the
structural material in electrochemical fabrication technology.
[0155] Since tooling often requires high strength, diffusion
bonding of the layers in tooling produced by electrochemical
fabrication technology may be carried out by heating the tooling to
a temperature which promotes diffusion across the layer interface.
This can be carried out either before or after removal of the
sacrificial material.
[0156] Tooling may also be fabricated indirectly--not as the direct
result of electrochemical fabrication technology, but for example,
by using an electrochemical fabrication technology-produced copper
electrode to electrical discharge machine tool steel which then
serves as the final tool.
[0157] Another Embodiment of the instant invention is shown in
FIGS. 26A and 26B. FIGS. 26A and 26B illustrate two different probe
tip configurations that may be used for probe cards or in other
electrical test environments. The probe electrodes 582 and 592,
respectively, are located within shields 584 and 594, respectively,
until the probe tip is approached at which point the shield is
allowed to drop away to allow contact between tips 586 and 596 with
pads to be tested. Probe cards are used to test and measure
integrated circuits during production. The move to higher
frequencies for these integrated circuits causes a higher demand to
be placed on the performance of probe cards. Further more as IC's
move to finer pitches, probes must be of smaller and finer pitch.
To improve operation of these probes at higher frequencies, it is
proposed herein and illustrated in FIGS. 26A and 26B that such
probes remain shielded (e.g. at ground potential) for as much of
the probe length as possible.
[0158] Another embodiment of the instant invention is illustrated
in FIG. 27. FIG. 27 illustrates a pressure sensor whose movement is
controlled by a bellows like structure. The sensor consists of
moveable plate 602, fixed plate 604, bellows structure 606 and
dielectric 608 that separates plates 602 and bellows 606 from plate
604. As pressure changes, the bellows can extend or alternatively
can retract, thus changing the separation between plates 602 and
604 and changing an associated capacitance which can be detected
and correlated to a given pressure differential. The differential
being that between the pressure outside the sensor and the pressure
inside sealed area 612.
[0159] An additional embodiment of the invention is illustrated in
FIGS. 28A-28D. FIG. 28A depicts a pair of capacitor plates 612 and
614 held apart by spacers 616 where extension rods 618 extend from
either side of the center of the capacitor by application of a
voltage differential between plate 612 and 614. The plates can be
made to attract one another and bend inward. Such bending will
cause displacement of extension rods 618 compressing their end to
end separation. Such a configuration may be used as an actuator.
Multiple such actuators can be combines together to form stacks
capable of more extensive end to end displacement. Appropriately
configured parallel configurations can be used to increase to
overall displacement force. A combination of series and parallel
configurations may also be useful. Such actuator combination, could
exert both greater force and increased displacement. A perspective
view of a single such actuator is shown in FIG. 29A where a
dielectric pad 622 is placed between the capacitor plates to
inhibit inadvertent shorting of them. FIG. 29B illustrates a
perspective view of three such stacked plates where electrical lead
lines 624(a), 624(b) and 624(c) extend along the sides of the
plates.
[0160] FIGS. 30A-30F illustrate some additional embodiments of the
present invention related to switches. FIG. 30A depicts a switch
702 that includes a moveable beam 704 positioned between two
actuation plates 706 and 708. Movable member 704 includes a contact
tip 712 which can be made to contact lead 714 when appropriately
actuated. This embodiment of FIG. 30A can use upper electrode 706
in addition to any spring force associated with moveable member 704
to help separate contactor 712 from lead 714. The embodiment of
FIG. 30B can be used in an analogous manner to that of 30A where an
additional contactor 718 is included which may be used to give the
switch a double throw capability. FIG. 30C illustrates another
switch embodiment that uses an electrode configuration 722 that is
at least partially conformed to the shape of moving member 724 when
moving member is deflected to contact element 726. FIG. 30D depicts
a double throw switch embodiment which includes contour electrodes
that at least partially mimic the shape of moving member 734 when
deflected to contact elements 736 or 738. FIG. 30F depicts another
alternative switch embodiment where a central electrode 744 is
activated to pull an upper moveable member 746 and a lower movable
member 748 together to make contact between elements 746 and 748.
FIG. 31A-31C depict additional embodiments of the present invention
FIG. 31A depicts a beam 772 that is located above an electrode 774
where the electrode has walls 776 that approach the sides of beam
772. As a potential is placed between beam 772 and electrode 774,
beam 772 is attracted downward toward the electrode where the
attraction force is stronger then it would have been if electrode
774 were just a flat plate. Side walls 776 do not inhibit the
motion of beam 772, but do lower the activation voltage necessary
to displace bean 772. The beam 772 may be a cantilever beam
supported at one end which is opposite to the end of the view of
FIG. 31A. Alternatively, beam 772 may be a spring loaded plate that
can move vertically up and down as apposed to undergoing a bending
motion. FIG. 31B depicts a similar embodiment to that of 31A with
the exception that an upper electrode 782 is depicted which may be
used to deflect the beam upward or to aid in pulling or releasing
the beam from a contact position when it is deflected toward
electrode 774. FIG. 31C shows an alternative embodiment where a
beam 784 can be deflected in any of four directions by electrodes
786(a), 786(b), 786(c) or 786(d). As with some of the other
embodiments alternatives to the embodiments of FIG. 31A-31C may
include dielectric stops, and the like, which may be helpful in
minimizing contact between the beam and the electrodes.
[0161] The patent applications in the following table are hereby
incorporated by reference herein as if set forth in full. The gist
of each patent application is included in the table to aid the
reader in finding specific types of teachings. It is not intended
that the incorporation of subject matter be limited to those topics
specifically indicated, but instead the incorporation is to include
all subject matter found in these applications. The teachings in
these incorporated applications can be combined with the teachings
of the instant application in many ways. For example, the various
apparatus configurations disclosed in these referenced applications
may be used in conjunction with the novel features of the instant
invention to provide various alternative apparatus that include the
functionality disclosed herein:
TABLE-US-00001 US Application No. Title Filing Date Brief
Description US App. No. 09/488,142 Method for Electrochemical
Fabrication Jan. 20, 2000 This application is a divisional of the
application that led to the above noted '630 patent. This
application describes the basics of conformable contact mask
plating and electrochemical fabrication including various
alternative methods and apparatus for practicing EFAB as well as
various methods and apparatus for constructing conformable contact
masks US App. No. 09/755,985 Microcombustor and Combustion-Based
Thermoelectric Microgenerator Jan. 5, 2001 Describes a generally
toroidal counterflow heat exchanger and electric current
microgenerator that can be formed using electrochemical
fabrication. US App. No. 60/379,136 Selective Electrochemical
Deposition Methods Having Enhanced Uniform May 7, 2002 Deposition
Capabilities Describes conformable contact mask processes for
forming selective depositions of copper using a copper
pyrophosphate plating solution that allows simultaneous deposition
to at least one large area (greater than about 1.44 mm.sup.2) and
at least one small area (smaller than about 0.05 mm.sup.2) wherein
the thickness of deposition to the smaller area is no less than
one-half the deposition thickness to the large area when the
deposition to the large area is no less than about 10 .mu.m in
thickness and where the copper pyrophosphate solution contains at
least 30 g/L of copper. The conformable contact mask process is
particularly focused on an electrochemical fabrication process for
producing three-dimensional structures from a plurality of adhered
layers. US App. No. 60/379,131 Selective Electrodeposition Using
Conformable Contact Masks Having May 7, 2002 Enhanced Longevity
Describes conformable contact masks that include a support
structure and a patterned elastomeric material and treating the
support structure with a corrosion inhibitor prior to combining the
support and the patterned elastomeric material to improve the
useful life of the mask. Also describes operating the plating bath
at a low temperature so as to extend the life of the mask. US App.
No. 60/379,132 Methods and Apparatus for Monitoring Deposition
Quality During May 7, 2002 Conformable Contact Mask Plating
Operations Describes an electrochemical fabrication process and
apparatus that includes monitoring of at least one electrical
parameter (e.g. voltage) during selective deposition using
conformable contact masks where the monitored parameter is used to
help determine the quality of the deposition that was made. If the
monitored parameter indicates that a problem occurred with the
deposition, various remedial operations are undertaken to allow
successful formation of the structure to be completed. US App. No.
60/329,654 "Innovative Low-Cost Manufacturing Technology for High
Aspect Ratio Oct. 15, 2001 Microelectromechanical Systems (MEMS)" A
conformable contact masking technique where the depth of deposition
is enhanced by pulling the mask away from the substrate as
deposition is occurring in such away that the seal between the
conformable portion of the mask and the substrate shifts from the
face of the conformal material and the opposing face of the
substrate to the inside edges of the conformable material and the
deposited material. US App. No. 60/379,129 Conformable Contact
Masking Methods and Apparatus Utilizing In Situ May 7, 2002
Cathodic Activation of a Substrate An electrochemical fabrication
process benefiting from an in situ cathodic activation of nickel is
provided where prior to nickel deposition, the substrate is exposed
to the desired nickel plating solution and a current less than that
capable of causing deposition is applied through the plating
solution to the substrate (i.e. cathode) to cause activation of the
substrate, after which, without removing the substrate from the
plating bath, the current is increased to a level which causes
deposition to occur. US App. No. 60/379,134 Electrochemical
Fabrication Methods With Enhanced Post Deposition May 7, 2002
Processing An electrochemical fabrication process for producing
three- dimensional structures from a plurality of adhered layers is
provided where each layer includes at least one structural material
(e.g. nickel) and at least one sacrificial material (i.e. copper)
that will be etched away from the structural material after the
formation of all layers have been completed. A copper etchant
containing chlorite (e.g. Enthone C-38) is combined with a
corrosion inhibitor (e.g. sodium nitrate) to prevent pitting of the
structural material during removal of the sacrificial material. US
App. No. 60/364,261 Electrochemical Fabrication Method and
Apparatus for Producing Three- Mar. 13, 2002 Dimensional Structures
Having Improved Surface Finish An electrochemical fabrication
(EFAB) process and apparatus are provided that remove material
deposited on at least one layer using a first removal process that
includes one or more operations having one or more parameters, and
remove material deposited on at least one different layer using a
second removal process that includes one or more operations having
one or more parameters, wherein the first removal process differs
from the second removal process by inclusion of at least one
different operation or at least one different parameter. US App.
No. 60/379,133 Method of and Apparatus for Forming
Three-Dimensional Structures Integral May 7, 2002 With
Semiconductor Based Circuitry An electrochemical fabrication (e.g.
by EFAB .TM.) process and apparatus are provided that can form
three-dimensional multi-layer structures using semiconductor based
circuitry as a substrate. Electrically functional portions of the
structure are formed from structural material (e.g. nickel) that
adheres to contact pads of the circuit. Aluminum contact pads and
silicon structures are protected from copper diffusion damage by
application of appropriate barrier layers. In some embodiments,
nickel is applied to the aluminum contact pad via solder bump
formation techniques using electroless nickel plating. US App. No.
60/379,176 Selective Electrochemical Deposition Methods Using
Pyrophosphate Copper May 7, 2002 Plating Baths Containing Citrate
Salts An electrochemical fabrication (e.g. by EFAB .TM.) process
and apparatus are provided that can form three-dimensional
multi-layer structures using pyrophosphate copper plating solutions
that contain a citrate salt. In preferred embodiments the citrate
salts are provided in concentrations that yield improved anode
dissolution, reduced formation of pinholes on the surface of
deposits, reduced likelihood of shorting between anode and cathode
during deposition processes, and reduced plating voltage throughout
the period of deposition. A preferred citrate salt is ammonium
citrate in concentrations ranging from somewhat more that about 10
g/L for 10 mA/cm.sup.2 current density to as high as 200 g/L or
more for a current density as high as 40 mA/cm.sup.2. US App. No.
60/379,135 Methods of and Apparatus for Molding Structures Using
Sacrificial Metal May 7, 2002 Patterns Molded structures, methods
of and apparatus for producing the molded structures are provided.
At least a portion of the surface features for the molds are formed
from multilayer electrochemically fabricated structures (e.g.
fabricated by the EFAB .TM. formation process), and typically
contain features having resolutions within the 1 to 100 .mu.m
range. The layered structure is combined with other mold
components, as necessary, and a molding material is injected into
the mold and hardened. The layered structure is removed (e.g. by
etching) along with any other mold components to yield the molded
article. In some embodiments portions of the layered structure
remain in the molded article and in other embodiments an additional
molding material is added after a partial or complete removal of
the layered structure. US App. No. 60/379,177 Electrochemically
Fabricated Structures Having Dielectric Bases and May 7, 2002
Methods of and Apparatus for Producing Such Structures Multilayer
structures are electrochemically fabricated (e.g. by EFAB .TM.) on
a temporary conductive substrate and are there after are bonded to
a permanent dielectric substrate and removed from the temporary
substrate. The structures are formed from top layer to bottom
layer, such that the bottom layer of the structure becomes adhered
to the permanent substrate. The permanent substrate may be a solid
sheet that is bonded (e.g. by an adhesive) to the layered structure
or the permanent substrate may be a flowable material that is
solidified adjacent to or partially surrounding a portion of the
structure with bonding occurs during solidification. The multilayer
structure may be released from a sacrificial material prior to
attaching the permanent substrate or more preferably it may be
released after attachment. US App. No. 60/379,182 Electrochemically
Fabricated Hermetically Sealed Microstructures and May 7, 2002
Methods of and Apparatus for Producing Such Structures Multilayer
structures are electrochemically fabricated (e.g. by EFAB .TM.)
from at least one structural material (e.g. nickel), at least one
sacrificial material (e.g. copper), and at least one sealing
material (e.g. solder). The layered structure is made to have a
desired configuration which is at least partially and immediately
surrounded by sacrificial material which is in turn surrounded
almost entirely by structural material. The surrounding structural
material includes openings in the surface through which etchant can
attack and remove trapped sacrificial material found within.
Sealing material is located near the openings. After removal of the
sacrificial material, the box is evacuated or filled with a desired
gas or liquid. Thereafter, the sealing material is made to flow,
seal the openings, and resolidify. US App. No. 60/430,809
Electrochemically Fabricated Hermetically Sealed Microstructures
and Dec. 3, 2002. Methods of and Apparatus for Producing Such
Structures Multilayer structures are electrochemically fabricated
(e.g. by EFAB .TM.) from at least one structural material (e.g.
nickel), at least one sacrificial material (e.g. copper), and at
least one sealing material (e.g. solder). The layered structure is
made to have a desired configuration which is at least partially
and immediately surrounded by sacrificial material which is in turn
surrounded almost entirely by structural material. The surrounding
structural material includes openings in the surface though which
etchant can attack and remove trapped sacrificial material found
within. Sealing material is located near the openings. After
removal of the sacrificial material, the box is evacuated or filled
with a desired gas or liquid. Thereafter, the sealing material is
made to flow, seal the openings, and resolidify.
US App. No. 60/379,184 Multistep Release Method for
Electrochemically Fabricated Structures May 7, 2002 Multilayer
structures are electrochemically fabricated (e.g. by EFAB .TM.)
from at least one structural material (e.g. nickel), that is
configured to define a desired structure and which may be attached
to a support structure, and at least a first sacrificial material
(e.g. copper) that surrounds the desired structure, and at least
one more material which surrounds the first sacrificial material
and which will function as a second sacrificial material. The
second sacrificial material is removed by an etchant and/or process
that does not attack the first sacrificial material. Intermediate
post processing activities may occur, and then the first
sacrificial material is removed by an etchant or process that does
not attack the at least one structural material to complete the
release of the desired structure. US App. No. 60/392,531 Miniature
RF and Microwave Components and Methods for Fabricating Such Jun.
27, 2002 Components RF and microwave radiation directing or
controlling components are provided that are monolithic, that are
formed from a plurality of electrodeposition operations, that are
formed from a plurality of deposited layers of material, that
include inductive and capacitive stubs or spokes that short a
central conductor of a coaxial component to the an outer conductor
of the component, that include non-radiation-entry and
non-radiation-exit channels that are useful in separating
sacrificial materials from structural materials and that are
useful, and/or that include surface ripples on the inside surfaces
of some radiation flow passages. Preferred formation processes use
electrochemical fabrication techniques (e.g. including selective
depositions, bulk depositions, etching operations and planarization
operations) and post- deposition processes (e.g. selective etching
operations and/or back filling operations). US App. No. 60/415,374
Monolithic Structures Including Alignment and/or Retention Fixtures
Oct. 1, 2002 for Accepting Components Permanent or temporary
alignment and/or retention structures for receiving multiple
components are provided. The structures are preferably formed
monolithically via a plurality of deposition operations (e.g.
electrodeposition operations). The structures typically include two
or more positioning fixtures that control or aid in the positioning
of components relative to one another, such features may include
(1) positioning guides or stops that fix or at least partially
limit the positioning of components in one or more orientations or
directions, (2) retention elements that hold positioned components
in desired orientations or locations, and (3) positioning and/or
retention elements that receive and hold adjustment modules into
which components can be fixed and which in turn can be used for
fine adjustments of position and/or orientation of the components.
US App. No. 10/271,574 Methods of and Apparatus for Making High
Aspect Ratio Oct. 15, 2002 Microelectromechanical Structures
Various embodiments of the invention present techniques for forming
structures (e.g. HARMS-type structures) via an electrochemical
extrusion (ELEX .TM.) process. Preferred embodiments perform the
extrusion processes via depositions through anodeless conformable
contact masks that are initially pressed against substrates that
are then progressively pulled away or separated as the depositions
thicken. A pattern of deposition may vary over the course of
deposition by including more complex relative motion between the
mask and the substrate elements. Such complex motion may include
rotational components or translational motions having components
that are not parallel to an axis of separation. More complex
structures may be formed by combining the ELEX .TM. process with
the selective deposition, blanket deposition, planarization,
etching, and multi-layer operations of EFAB .TM.. US App. No.
60/422,008 EFAB Methods and Apparatus Including Spray Metal Coating
Processes Oct. 29, 2002 Various embodiments of the invention
present techniques for forming structures via a combined
electrochemical fabrication process and a thermal spraying process.
In a first set of embodiments, selective deposition occurs via
conformable contact masking processes and thermal spraying is used
in blanket deposition processes to fill in voids left by selective
deposition processes. In a second set of embodiments, selective
deposition via a conformable contact masking is used to lay down a
first material in a pattern that is similar to a net pattern that
is to be occupied by a sprayed metal. In these other embodiments a
second material is blanket deposited to fill in the voids left in
the first pattern, the two depositions are planarized to a common
level that may be somewhat greater than a desired layer thickness,
the first material is removed (e.g. by etching), and a third
material is sprayed into the voids left by the etching operation.
The resulting depositions in both the first and second sets of
embodiments are planarized to a desired layer thickness in
preparation for adding additional layers to form three-dimensional
structures from a plurality of adhered layers. In other
embodiments, additional materials may be used and different
processes may be used. US App. No. 60/422,007 Medical Devices and
EFAB Methods and Apparatus for Producing Them Oct. 29, 2002 Various
embodiments of the invention present miniature medical devices that
may be formed totally or in part using electrochemical fabrication
techniques. Sample medical devices include micro-tweezers or
forceps, internally expandable stents, bifurcated or side branch
stents, drug eluting stents, micro- valves and pumps, rotary
ablation devices, electrical ablation devices (e.g. RF devices),
micro-staplers, ultrasound catheters, and fluid filters. In some
embodiments devices may be made out of a metal material while in
other embodiments they may be made from a material (e.g. a polymer)
that is molded from an electrochemically fabricated mold.
Structural materials may include gold, platinum, silver, stainless
steel, titanium or pyrolytic carbon- coated materials such as
nickel, copper, and the like. US App. No. 60/422,982 Sensors and
Actuators and Methods and Apparatus for Producing Them Nov. 1, 2002
Various embodiments of the invention present sensors or actuators
that include a plurality of capacitor (i.e. conductive) plates that
can interact with one another to change an electrical parameter
that may be correlated to a physical parameter such as pressure,
movement, temperature, or the like or that may be driven may an
electrical signal to cause physical movement. In some embodiments
the sensors or actuators are formed at least in part via
electrochemical fabrication (e.g. EFAB). US App. No. 60/429,483
Multi-cell Masks and Methods and Apparatus for Using Such Masks To
Form Nov. 26, 2002. Three-Dimensional Structures Multilayer
structures are electrochemically fabricated via depositions of one
or more materials in a plurality of overlaying and adhered layers.
Selectivity of deposition is obtained via a multi-cell controllable
mask. Alternatively, net selective deposition is obtained via a
blanket deposition and a selective removal of material via a
multi-cell mask. Individual cells of the mask may contain
electrodes comprising depositable material or electrodes capable of
receiving etched material from a substrate. Alternatively,
individual cells may include passages that allow or inhibit ion
flow between a substrate and an external electrode and that include
electrodes or other control elements that can be used to
selectively allow or inhibit ion flow and thus inhibit significant
deposition or etching. US App. No. 60/429,484 Non-Conformable Masks
and Methods and Apparatus for Forming Three- Nov. 26, 2002.
Dimensional Structures Electrochemical Fabrication may be used to
form multilayer structures (e.g. devices) from a plurality of
overlaying and adhered layers. Masks, that are independent of a
substrate to be operated on, are generally used to achieve
selective patterning. These masks may allow selective deposition of
material onto the substrate or they may allow selective etching of
a substrate where after the created voids may be filled with a
selected material that may be planarized to yield in effect a
selective deposition of the selected material. The mask may be used
in a contact mode or in a proximity mode. In the contact mode the
mask and substrate physically mate to form substantially
independent process pockets. In the proximity mode, the mask and
substrate are positioned sufficiently close to allow formation of
reasonably independent process pockets. In some embodiments, masks
may have conformable contact surfaces (i.e. surfaces with
sufficient deformability that they can substantially conform to
surface of the substrate to form a seal with it) or they may have
semi-rigid or even rigid surfaces. Post deposition etching
operations may be performed to remove flash deposits (thin
undesired deposits). US App. No. 10/309,521 Miniature RF and
Microwave Components and Methods for Fabricating Such Dec. 3, 2002.
Components RF and microwave radiation directing or controlling
components are provided that may be monolithic, that may be formed
from a plurality of electrodeposition operations and/or from a
plurality of deposited layers of material, that may include
switches, inductors, antennae, transmission lines, filters, and/or
other active or passive components. Components may include
non-radiation-entry and non-radiation-exit channels that are useful
in separating sacrificial materials from structural materials.
Preferred formation processes use electrochemical fabrication
techniques (e.g. including selective depositions, bulk depositions,
etching operations and planarization operations) and
post-deposition processes (e.g. selective etching operations and/or
back filling operations).
[0162] Additional material concerning microdevices and their
fabrication can be found in the following three books which are
hereby incorporated herein by reference as if set forth in full
herein: [0163] 1. Multiple authors, The MEMS Handbook, edited by
Mohamed Gad-El-Hak, CRC Press, 2002. [0164] 2. M. Madou,
Fundamentals of Microfabrication, CRC Press, 2002. [0165] 3.
Multiple authors, Micromechanics and MEMS, edited by William
Trimmer, IEEE Press, 1997.
[0166] Various other embodiments of the present invention exist.
Some of these embodiments may be based on a combination of the
teachings herein with various teachings incorporated herein by
reference. Some embodiments may not use any blanket deposition
process and/or they may not use a planarization process. Some
embodiments may involve the selective deposition of a plurality of
different materials on a single layer or on different layers. Some
embodiments may use blanket deposition processes that are not
electrodeposition processes. Some embodiments may use selective
deposition processes on some layers that are not conformable
contact masking processes and are not even electrodeposition
processes. Some embodiments may use the non-conformable contact
mask or non-contact masking techniques set forth in the above
referenced U.S. Provisional Application No. 60/429,483.
[0167] Some embodiments may use nickel as a structural material
while other embodiments may use different materials such as copper,
gold, silver, or any other electrodepositable materials that can be
separated from the a sacrificial material. Some embodiments may use
copper as the structural material with or without a sacrificial
material. Some embodiments may remove a sacrificial material while
other embodiments may not. In some embodiments the sacrificial
material may be removed by a chemical etching operation, an
electrochemical operation, or a melting operation. In some
embodiments the anode may be different from the conformable contact
mask support and the support may be a porous structure or other
perforated structure. Some embodiments may use multiple conformable
contact masks with different patterns so as to deposit different
selective patterns of material on different layers and/or on
different portions of a single layer. In some embodiments, the
depth of deposition will be enhanced by pulling the conformable
contact mask away from the substrate as deposition is occurring in
a manner that allows the seal between the conformable portion of
the CC mask and the substrate to shift from the face of the
conformal material to the inside edges of the conformable
material.
[0168] In view of the teachings herein, many further embodiments,
alternatives in design and uses of the instant invention will be
apparent to those of skill in the art. As such, it is not intended
that the invention be limited to the particular illustrative
embodiments, alternatives, and uses described above but instead
that it be solely limited by the claims presented hereafter.
* * * * *