U.S. patent application number 11/928206 was filed with the patent office on 2008-05-08 for methods for electrochemically fabricating structures using adhered masks, incorporating dielectric sheets, and/or seed layers that are partially removed via planarization.
This patent application is currently assigned to Microfabrica Inc.. Invention is credited to Richard T. Chen, Willa M. Larsen, Michael S. Lockard, Dannis R. Smalley.
Application Number | 20080105647 11/928206 |
Document ID | / |
Family ID | 33458754 |
Filed Date | 2008-05-08 |
United States Patent
Application |
20080105647 |
Kind Code |
A1 |
Lockard; Michael S. ; et
al. |
May 8, 2008 |
Methods for Electrochemically Fabricating Structures Using Adhered
Masks, Incorporating Dielectric Sheets, and/or Seed layers That Are
Partially Removed Via Planarization
Abstract
Embodiments of the present invention provide mesoscale or
microscale three-dimensional structures (e.g. components, device,
and the like). Embodiments relate to one or more of (1) the
formation of such structures which incorporate sheets of dielectric
material and/or wherein seed layer material used to allow
electrodeposition over dielectric material is removed via
planarization operations; (2) the formation of such structures
wherein masks used for at least some selective patterning
operations are obtained through transfer plating of masking
material to a surface of a substrate or previously formed layer,
and/or (3) the formation of such structures wherein masks used for
forming at least portions of some layers are patterned on the build
surface directly from data representing the mask configuration,
e.g. in some embodiments mask patterning is achieved by selectively
dispensing material via a computer controlled inkjet nozzle or
array or via a computer controlled extrusion device.
Inventors: |
Lockard; Michael S.; (Lake
Elizabeth, CA) ; Smalley; Dannis R.; (Newhall,
CA) ; Larsen; Willa M.; (Reseda, CA) ; Chen;
Richard T.; (Burbank, CA) |
Correspondence
Address: |
Microfabrica Inc.
7911 Haskell Avenue
Van Nuys
CA
91406
US
|
Assignee: |
Microfabrica Inc.
|
Family ID: |
33458754 |
Appl. No.: |
11/928206 |
Filed: |
October 30, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10841300 |
May 7, 2004 |
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11928206 |
Oct 30, 2007 |
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60468979 |
May 7, 2003 |
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60469053 |
May 7, 2003 |
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60533891 |
Dec 31, 2003 |
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Current U.S.
Class: |
216/11 ;
257/E21.581; 257/E21.582; 427/58 |
Current CPC
Class: |
C25D 5/10 20130101; C23C
18/1605 20130101; C25D 5/022 20130101; C25D 1/003 20130101; B33Y
10/00 20141201; C23C 18/1657 20130101; H01L 21/76838 20130101; H01L
21/7682 20130101 |
Class at
Publication: |
216/011 ;
427/058 |
International
Class: |
B05D 5/12 20060101
B05D005/12; B44C 1/22 20060101 B44C001/22 |
Claims
1. A process for forming a multilayer three-dimensional structure,
comprising: (a) forming and adhering a layer of material to a
substrate, wherein the substrate may include previously formed
layers; and (b) repeating the forming and adhering operation of (a)
a plurality of times to build up a three-dimensional structure from
a plurality of adhered layers; wherein the formation of at least
one layer comprises: (i) forming a desired pattern of dielectric
material on the substrate or on previously deposited material
wherein the patterning of the dielectric results in at least one
void in the dielectric material that exposes a portion of the
substrate or previously deposited material; (ii) applying a seed
layer material to the dielectric material and to the exposed
portions of the substrate or previously deposited material; (iii)
depositing a conductive material into the at least one void in the
dielectric; and (iv) after depositing the conductive material,
removing at least a portion of the seed layer material located on
the dielectric material.
2. The process of claim 1 wherein operations (i)-(iv) are performed
during the formation of a plurality of layers.
3. The process of claim 1 wherein the removing of the seed layer
material comprises a planarization operation.
4. The process of claim 1 wherein the removing of the seed layer
material comprises an etching operation.
5. The process of claim 1 wherein the forming a desired pattern of
dielectric comprises the deposition of a liquid dielectric over the
substrate or previously formed layer, followed by the subsequent
solidification and patterning of the dielectric material.
6. The process of claim 1 wherein the forming a desired pattern of
dielectric comprises the adhesion of a sheet of dielectric material
to the substrate or previously formed layer, followed by the
subsequent patterning of the dielectric material.
7. The process of claim 1 wherein the dielectric material comprises
a photoresist material.
8. The process of claim 1 additionally comprising: (v) removing at
least a portion of the dielectric material to create at least a
second void; and (vi) then depositing a selected material into the
second void.
9. The process of claim 1 additionally comprising: (v) selectively
etching into the conductive material to form at least one second
void; (vi) depositing a seed layer into the at least second void;
and (vii) depositing a second conductive material into the at least
one second void.
10. The process of claim 1 additionally comprising: (v) selectively
forming at least one second void in the dielectric material; (vi)
depositing a seed layer into the at least second void; and (vii)
depositing a second conductive material into the at least one
second void.
11. The process of claim 1 additionally comprising: (v) depositing
an adhesion layer material onto the dielectric material and onto
the substrate or previously deposited material prior to applying
the seed layer material.
12. A process for forming a multilayer three-dimensional structure,
comprising: (a) forming and adhering a layer of material to a
substrate, wherein the substrate may include previously formed
layers; and (b) repeating the forming and adhering operation of (a)
a plurality of times to build up a three-dimensional structure from
a plurality of adhered layers; wherein the formation of at least
one layer comprises: (i) forming a desired pattern of a first
material on the substrate or on previously deposited material
wherein the patterning of the first material results in at least
one void in the first material that exposes a portion of the
substrate or previously deposited material; (ii) applying a seed
layer material to the first material and to the exposed portions of
the substrate or previously deposited material; (iii) depositing a
first conductive material into the at least one void in the first
material; and (iv) after depositing the first conductive material,
removing at least a portion of the seed layer material located on
the first material.
13. The process of claim 12 wherein the first material comprises a
dielectric.
14. The process of claim 12 wherein the first material comprises a
conductive material.
15. The process of claim 12 wherein the substrate has a dielectric
surface onto which the first material is to be deposited
16. The process of claim 12 wherein the substrate has a conductive
surface onto which the first material is to be deposited
17. The process of claim 12 wherein the substrate has a surface
having at least two parts, one of which is conductive and other of
which is dielectric.
18. The process of claim 12 wherein the applying of the seed layer
comprises a sputtering operation.
19. The process of claim 12 wherein the applying of the seed layer
comprises a physical or chemical vapor deposition operation.
20. A process for forming a multilayer three-dimensional structure,
comprising: (a) forming and adhering a layer of material to a
substrate, wherein the substrate may include previously formed
layers; and (b) repeating the forming and adhering operation of (a)
a plurality of times to build up a three-dimensional structure from
a plurality of adhered layers; wherein the formation of at least
one layer comprises: (i) forming a desired pattern of dielectric
material on the substrate or on previously deposited material; and
thereafter performing at least one of the following: (1) depositing
a structural conductive material; (2) depositing a sacrificial
conductive material; or (3) depositing a seed layer.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/841,300, filed May 7, 2004 which claims
benefit of the following U.S. Provisional Patent Applications
60/468,979, filed May 7, 2003; 60/469,053, filed May 7, 2003; and
60/533,891, filed Dec. 31, 2003. Each of these applications is
hereby incorporated herein by references as if set forth in full
herein.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of
electrochemical fabrication and the associated formation of
three-dimensional structures (e.g. microscale or mesoscale
structures). In particular, it relates to one or more of (1) the
formation of such structures which incorporate sheets of dielectric
material and/or wherein seed layer material used to allow
electrodeposition over dielectric material is removed via
planarization operations; (2) the formation of such structures
wherein masks used for at least some selective patterning
operations are obtained through transfer plating of masking
material or precursor material to a surface of a substrate or
previously formed layer, and/or (3) the formation of such
structures wherein masks used for at least portions of some layers
are patterned on the build surface directly from data representing
the mask configuration, e.g. in some embodiments mask patterning is
achieved by selectively dispensing material, for example, via a
computer controlled inkjet nozzle, ink jet array, or a computer
controlled extrusion device.
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.TM. Inc. (formerly MEMGen.RTM. Corporation) of
Burbank, 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.TM.
Inc. (formerly MEMGen.RTM. Corporation) of Burbank, Calif. such
masks have come to be known as INSTANT MASKS.TM. and the process
known as INSTANT MASKING 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,
Aug. 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. 1(a)-1(c). FIG. 1(a) 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. 1(a) 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. 1(b). After deposition, the CC mask is
separated, preferably non-destructively, from the substrate 6 as
shown in FIG. 1(c). 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. 1(d)-1(f). FIG. 1(d) shows an anode 12' separated from a mask
8' that includes a patterned conformable material 10' and a support
structure 20. FIG. 1(d) also depicts substrate 6 separated from the
mask 8'. FIG. 1(e) illustrates the mask 8' being brought into
contact with the substrate 6. FIG. 1(f) illustrates the deposit 22'
that results from conducting a current from the anode 12' to the
substrate 6. FIG. 1(g) 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. 2(a)-2(f). 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. 2(a), 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. 2(b). FIG. 2(c) 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. 2(d). 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. 2(e).
The embedded structure is etched to yield the desired device, i.e.
structure 20, as shown in FIG. 2(f).
[0027] Various components of an exemplary manual electrochemical
fabrication system 32 are shown in FIGS. 3(a)-3(c). 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. 3(a) to 3(c) 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.
3(a) 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. 3(b) 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. 3(c) and includes a lapping plate 52 and associated motion
and control systems (not shown) for planarizing the
depositions.
[0031] The '630 patent also teaches that other methods may be used
to form contact masks (i.e. electroplating articles in the language
of the '630 patent) which include applying masking composition
selectively to a support by such processes as screen printing,
stencil printing and inkjet printing.
[0032] The '630 patent also teaches that methods similar to those
used in relief printing can also be used to fabricate
electroplating articles (i.e. contact masks). A cited example of
such a method includes: applying a liquid masking composition to a
relief pattern, which might be produced by patterning a high aspect
ratio photoresist such as AZ4620 or SU-8; pressing the relief
pattern/masking composition structure against a support such that
the masking composition adheres to the support; and removing the
relief pattern. The formed electroplating article includes a
support having a mask patterned with the inverse pattern of the
relief pattern.
[0033] The '630 patent additionally teaches the creation of an
electroplating article (i.e. a contact mask) by creating a relief
pattern on a support by etching of the support, or applying a
durable photoresist, e.g., SU-8; coating a flat, smooth sheet with
a thin, uniform layer of liquid masking composition; stamping the
support/resist against the coated sheet (i.e., like a stamp and
inkpad) to quickly mate and unmate the support/resist and the
masking composition (preferably the support and the sheet are kept
parallel); and curing the liquid masking composition.
[0034] In addition to teaching the use of CC masks for
electrodeposition purposes, the '630 patent also teaches that the
CC masks may be placed against a substrate with the polarity of the
voltage reversed and material may thereby be selectively removed
from the substrate. It indicates that such removal processes can be
used to selectively etch, engrave, and polish a substrate, e.g., a
plaque.
[0035] The '630 patent further indicates that the electroplating
methods and articles disclosed therein allow fabrication of devices
from thin layers of materials such as, e.g., metals, polymers,
ceramics, and semiconductor materials. It further indicates that
although the electroplating embodiments described therein have been
described with respect to the use of two metals, a variety of
materials, e.g., polymers, ceramics and semiconductor materials,
and any number of metals can be deposited either by the
electroplating methods therein, or in separate processes that occur
throughout the electroplating method. It indicates that a thin
plating base can be deposited, e.g., by sputtering, over a deposit
that is insufficiently conductive (e.g., an insulating layer) so as
to enable subsequent electroplating. It also indicates that
multiple support materials (i.e. sacrificial materials) can be
included in the electroplated element allowing selective removal of
the support materials.
[0036] Another method for forming microstructures from
electroplated metals (i.e. using electrochemical fabrication
techniques) is taught in U.S. Pat. No. 5,190,637 to Henry Guckel,
entitled "Formation of Microstructures by Multiple Level Deep X-ray
Lithography with Sacrificial Metal layers". This patent teaches the
formation of metal structure utilizing mask exposures. A first
layer of a primary metal is electroplated onto an exposed plating
base to fill a void in a photoresist, the photoresist is then
removed and a secondary metal is electroplated over the first layer
and over the plating base. The exposed surface of the secondary
metal is then machined down to a height which exposes the first
metal to produce a flat uniform surface extending across the both
the primary and secondary metals. Formation of a second layer may
then begin by applying a photoresist layer over the first layer and
then repeating the process used to produce the first layer. The
process is then repeated until the entire structure is formed and
the secondary metal is removed by etching. The photoresist is
formed over the plating base or previous layer by casting and the
voids in the photoresist are formed by exposure of the photoresist
through a patterned mask via X-rays or UV radiation.
[0037] The '637 patent teaches the locating of a plating base onto
a substrate in preparation for electroplating materials onto the
substrate. The plating base is indicated as typically involving the
use of a sputtered film of an adhesive metal, such as chromium or
titanium, and then a sputtered film of the metal that is to be
plated. It is also taught that the plating base may be applied over
an initial sacrificial layer of material on the substrate so that
the structure and substrate may be detached if desired. In such
cases after formation of the structure the plating base may be
patterned and removed from around the structure and then the
sacrificial layer under the plating base may be dissolved to free
the structure. Substrate materials mentioned in the '637 patent
include silicon, glass, metals, and silicon with protected
processed semiconductor devices. A specific example of a plating
base includes about 150 angstroms of titanium and about 300
angstroms of nickel, both of which are sputtered at a temperature
of 160.degree. C. In another example it is indicated that the
plating base may consist of 150 angstroms of titanium and 150
angstroms of nickel where both are applied by sputtering.
[0038] Even though electrochemical fabrication as taught and
practiced to date, has greatly enhanced the capabilities of
microfabrication, and in particular added greatly to the number of
metal layers that can be incorporated into a structure and to the
speed and simplicity in which such structures can be made, room for
enhancing the state of electrochemical fabrication exists. In
particular, a need exists for improved methods of forming adhered
masks for selectively patterning substrates or previously formed
layers or portions of layers and/or for incorporating structural
dielectric materials into electrochemically fabricated structures.
A need also exists for improved methods of applying and/or removing
seed layer material and possibly adhesion layer material that may
be used in allowing electrodeposition to occur over non-conductive
portions of previous layers.
SUMMARY OF THE INVENTION
[0039] It is an object of some aspects of the invention to provide
improved methods for forming adhered masks.
[0040] It is an object of some aspects of the invention to provide
an improved electrochemical fabrication technique that includes the
use of a tool for transferring masking material to substrates, or
previously formed layers.
[0041] It is an object of some aspects of the invention to provide
an improved electrochemical fabrication technique that includes the
direct patterning of masking material onto substrates and/or
previously formed layers.
[0042] It is an object of some aspects of the invention to provide
an improved electrochemical fabrication technique capable of
incorporating a structural dielectric material.
[0043] It is an object of some aspects of the invention to provide
an improved electrochemical fabrication technique capable of
incorporating a structural dielectric material in sheet form.
[0044] It is an object of some aspects of the invention to provide
an improved electrochemical fabrication technique that incorporates
structural dielectric materials and which removes selected portions
of seed layer material, and possibly adhesion layer material,
without need for etching operations.
[0045] It is an object of some aspects of the invention to provide
an improved electrochemical fabrication technique that incorporates
structural dielectric materials and which removes selected portions
of seed layer material, and possibly adhesion layer material, using
trimming or planarization operations.
[0046] It is an object of some aspects of the invention to provide
an improved electrochemical fabrication technique that incorporates
structural dielectric materials by depositing them over previously
formed layers and over one or more materials deposited in
association with formation of a current layer.
[0047] 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 one or more of the above objects alone or in
combination, or alternatively they may address some other object of
the invention that may be ascertained from the teachings herein. It
is not necessarily intended that all objects be addressed by any
single aspect of the invention even though that may be the case
with regard to some aspects.
[0048] In a first aspect of the invention a process for forming a
multilayer three-dimensional structure includes: (a) forming and
adhering a layer of material to a substrate, wherein the substrate
may include previously formed layers; and (b) repeating the forming
and adhering operation of (a) a plurality of times to build up a
three-dimensional structure from a plurality of adhered layers;
wherein the formation of at least one layer comprises: (i) forming
a desired pattern of dielectric material on the substrate or on
previously deposited material wherein the patterning of the
dielectric results in at least one void in the dielectric material
that exposes a portion of the substrate or previously deposited
material; (ii) applying a seed layer material to the dielectric
material and to the exposed portions of the substrate or previously
deposited material; (iii) depositing a conductive material into the
at least one void in the dielectric; and (iv) after depositing the
conductive material, removing at least a portion of the seed layer
material located on the dielectric material.
[0049] In a second aspect of the invention a process for forming a
multilayer three-dimensional structure includes: (a) forming and
adhering a layer of material to a substrate, wherein the substrate
may include previously formed layers; and (b) repeating the forming
and adhering operation of (a) a plurality of times to build up a
three-dimensional structure from a plurality of adhered layers;
wherein the formation of at least one layer comprises: (i) forming
a desired pattern of a first material on the substrate or on
previously deposited material wherein the patterning of the first
material results in at least one void in the first material that
exposes a portion of the substrate or previously deposited
material; (ii) applying a seed layer material to the first material
and to the exposed portions of the substrate or previously
deposited material; (iii) depositing a first conductive material
into the at least one void in the first material; and (iv) after
depositing the first conductive material, removing at least a
portion of the seed layer material located on the first
material.
[0050] In a third aspect of the invention a process for forming a
multilayer three-dimensional structure includes: (a) forming and
adhering a layer of material to a substrate, wherein the substrate
may include previously formed layers; and (b) repeating the forming
and adhering operation of (a) a plurality of times to build up a
three-dimensional structure from a plurality of adhered layers;
wherein the formation of at least one layer comprises: (i) forming
a desired pattern of dielectric material on the substrate or on
previously deposited material; and thereafter performing at least
one of the following: (1) depositing a structural conductive
material; (2) depositing a sacrificial conductive material; or (3)
depositing a seed layer.
[0051] In a fourth aspect of the invention a process for forming a
multilayer three-dimensional structure includes: (a) forming and
adhering a layer of material to a substrate, wherein the substrate
may include previously formed layers; and (b) repeating the forming
and adhering operation of (a) a plurality of times to build up a
three-dimensional structure from a plurality of adhered layers;
wherein the formation of at least one layer comprises: (i) forming
a desired pattern of a first material on the substrate or on
previously deposited material; and thereafter applying a non-planar
seed layer material which will be used as base onto which a second
material will be subsequently electrodeposited.
[0052] In a fifth aspect of the invention a fabrication process for
forming a multi-layer three-dimensional structure, includes: (a)
forming and adhering a layer of material to a previously formed
layer and/or to a substrate; and (b) repeating the forming and
adhering operation of (a) a plurality of times to build up a
three-dimensional structure from a plurality of adhered layers;
wherein the formation of a given layer, includes: (1) selectively
transferring a pre-patterned precursor of a masking material which
is transformed into a solidified masking material of desired
thickness and cross-sectional configuration and adhered to the
substrate or a previously formed layer, wherein the mask has at
least one extended region of mask material through which at least
one void extends, wherein the mask material includes a dielectric,
or (1') selectively transferring a pre-patterned mask material of
desired thickness and cross-sectional configuration to a substrate
or previously formed layer and adhering said mask material to the
substrate or a previously formed layer, wherein the mask has at
least one extended region of mask material through which at least
one void extends, wherein the mask material includes a dielectric;
and further includes (2) depositing a first material onto a portion
of the substrate or previously formed layer through the at least
one void in the mask to form a portion of the given layer; and (3)
removing the mask material to leave at least one opening which
extends through the deposited first material on the given layer;
(4) depositing a second material into the opening through the
deposited first material on the given layer; and (5) planarizing at
least one of the deposited materials to a level that bounds the
given layer.
[0053] In a sixth aspect of the invention a fabrication process for
forming a multi-layer three-dimensional structure, includes: (a)
forming and adhering a layer of material to a previously formed
layer and/or to a substrate; and (b) repeating the forming and
adhering operation of (a) a plurality of times to build up a
three-dimensional structure from a plurality of adhered layers;
wherein the formation of a given layer, includes (1) selectively
transferring a pre-patterned precursor of a masking material which
is transformed into a solidified masking material of desired
thickness and cross-sectional configuration and adhered to the
substrate or a previously formed layer, wherein the mask has at
least one extended region of mask material through which at least
one void extends, or (1') selectively transferring a pre-patterned
mask material of desired thickness and cross-sectional
configuration to a substrate or previously formed layer and
adhering said mask material to the substrate or a previously formed
layer, wherein the mask has at least one extended region of mask
material through which at least one void extends; and (2)
electrodepositing a first material onto a portion of the substrate
or previously formed layer through the at least one void in the
mask to form a portion of the given layer.
[0054] In a seventh aspect of the invention a fabrication process
for forming a three-dimensional structure, includes: (a)
selectively transferring, in association with the formation of a
given layer, a pre-patterned precursor of a masking material which
is transformed into a solidified masking material of desired
thickness and cross-sectional configuration and adhered to the
substrate or a previously formed layer, wherein the mask has at
least one extended region of mask material through which at least
one void extends, or (a') selectively transferring, in association
with the formation of a given layer, a pre-patterned mask material
of desired thickness and cross-sectional configuration to a
substrate or previously formed layer and adhering said mask
material to the substrate or a previously formed layer, wherein the
mask has at least one extended region of mask material through
which at least one void extends; and (b) electrodepositing a first
material into the at least one void to form a portion of the given
layer.
[0055] In a eighth aspect of the invention a fabrication process
for forming a multi-layer three-dimensional structure, includes:
(a) forming and adhering a layer of material to a previously formed
layer and/or to a substrate; and (b) repeating the forming and
adhering operation of (a) a plurality of times to build up a
three-dimensional structure from a plurality of adhered layers;
wherein the formation of at least a given layer, includes: (1)
selectively dispensing a mask material in association with the
formation of a given layer from at least one computer controlled
dispensing device to form a mask of desired thickness and
cross-sectional configuration onto the substrate or a previously
formed layer, wherein the mask has at least one extended region of
mask material through which at least one void extends, wherein the
mask material includes a dielectric; and (2) depositing a first
material onto a portion of the substrate or previously formed layer
through the at least one void in the mask to form a portion of the
given layer; and (3) removing the mask material to leave at least
one opening which extends through the deposited first material on
the given layer; (4) depositing a second material into the opening
through the deposited first material on the given layer; and (5)
planarizing at least one of the deposited materials to a level that
bounds the given layer.
[0056] In a specific variation of the eighth aspect of the
invention the depositing of the first material or of the second
material for the given layer includes an electrodeposition
operation; the at least one computer controlled dispensing device
includes an ink jet device; the at least one computer controlled
dispensing device includes an ink jet device with a plurality of
dispensing orifices; and/or the at least one computer controlled
dispensing device includes an extrusion device. In another specific
variation the mask material undergoes a phase change after being
dispensed; the mask material is reacted after dispensing and in a
further variation the reaction includes is made to occur by at
least one of (1) exposure of the deposited material to a selected
radiation, (2) exposure of the deposited material to a chemical,
and/or (3) exposure of the deposited material to heat.
[0057] In another specific variation the mask material is dispensed
as a plurality of droplets. In a further variation, the droplets
are initially dispensed in positions sufficiently offset such that
gaps exist between at least portions of the droplets and where
after additional dispensing occurs such that the gaps are filled in
with mask material. In even a further variation the additional
dispensing occurs at positions which are offset from the initially
dispensed positions.
[0058] In another specific variation the dispensing of mask
material occurs via the dispensing of droplets in two or more
stages where droplets dispensed in association with at least some
stages overlap, at least in part, droplets dispensed in association
with other stages and wherein earlier dispensed droplets are
allowed to transform prior to the dispensing of overlapping
droplets. In a further variation the offset positions in
non-boundary regions are along boundary regions are located along
lines that connect the initially dispensed positions.
[0059] In an additional specific variation the mask material is
dispensed as a plurality of droplets from a thermally driven ink
jet; the mask material is dispensed as a plurality of droplets from
a piezoelectric driven ink jet thermal ink jet.
[0060] In a ninth aspect of the invention a fabrication process for
forming a multi-layer three-dimensional structure, includes: (a)
forming and adhering a layer of material to a previously formed
layer and/or to a substrate; and (b) repeating the forming and
adhering operation of (a) a plurality of times to build up a
three-dimensional structure from a plurality of adhered layers;
wherein the formation of at least a given layer, includes: (1)
selectively dispensing a mask material in association with the
formation of a given layer from at least one computer controlled
dispensing device to form a mask of desired thickness and
cross-sectional configuration onto the substrate or a previously
formed layer, wherein the mask has at least one extended region of
mask material through which at least one void extends; and (2)
electrodepositing a first material onto a portion of the substrate
or previously formed layer through the at least one void in the
mask to form a portion of the given layer.
[0061] In a specification variation of the ninth aspect of the
invention the mask material includes a conductive material. In a
further variation the formation of at least a plurality of layers
additionally includes using the mask material as a building
material that remains in place for at least formation of a
plurality of layers. In a still further variation the formation of
the at least plurality of layers additionally includes: (3)
planarizing at least one of the mask material or the first material
located on a given layer.
[0062] In another specific variation of the ninth aspect of the
invention, the mask material includes a dielectric material. In a
further variation, the formation of at least a plurality of layers
additionally includes using the mask material as a building
material that remains in place for at least formation of a
plurality of layers. In a still further variation the formation of
the at least plurality of layers additionally depositing an
adhesion layer material and/or a seed layer material in association
with the formation of a given layer after dispensing of the mask
material such that the adhesion and/or seed layer material is
located within the at least one void and above the mask material.
In an even further variation the formation of the at least
plurality of layers additionally includes (3) planarizing at least
the adhesion layer material and/or seed layer material located
above the mask material and at least one of the mask material or
the first material located on a given layer such that the level of
the deposited material bounds the given layer.
[0063] In another variation the masking material is a dielectric
and the formation of the at least plurality of layers additionally
includes depositing an adhesion layer material and/or a seed layer
material in association with the formation of a given layer before
dispensing of the mask material such that the adhesion and/or seed
layer material is located within the at least one void and below
the mask material. In a further variation the formation of the at
least plurality of layers additionally includes: (3) removing the
mask material after deposition of the first material for the given
layer; (4) removing the adhesion layer material and/or seed layer
material used in association with the given layer; and thereafter
(5) depositing a second material in association with the given
layer which includes a dielectric. In a still further variation,
the formation of the at least plurality of layers additionally
includes: (3) after deposition of the second material, planarizing
at one of the deposited materials located on a given layer such
that the level of the planarized material bounds the given
layer.
[0064] In a tenth aspect of the invention a fabrication process for
forming a three-dimensional structure, includes: (a) selectively
dispensing a mask material in association with the formation of a
given layer from at least one computer controlled dispensing device
to form a mask of desired thickness and cross-sectional
configuration onto the substrate or a previously formed layer,
wherein the mask has at least one region of mask material through
which at least one void extends; and (b) electrodepositing a first
material into the at least one void to form a portion of the given
layer.
[0065] In a specific variation of the tenth aspect of the invention
the operations (a) and (b) are repeated a plurality of times over
previously formed layer to form a multi-layer three-dimensional
structure. In a further variation portions of at least some
previous layers are formed from depositions associated with
subsequent layers.
[0066] 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 are configured to implement 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
[0067] FIGS. 1(a)-1(c) schematically depict side views of various
stages of a CC mask plating process, while FIGS. 1(d)-(g)
schematically depict a side views of various stages of a CC mask
plating process using a different type of CC mask.
[0068] FIGS. 2(a)-2(f) 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.
[0069] FIGS. 3(a)-3(c) schematically depict side views of various
example subassemblies that may be used in manually implementing the
electrochemical fabrication method depicted in FIGS. 2(a)-2(f).
[0070] FIGS. 4(a)-4(i) schematically depict the formation of a
first layer of a structure using adhered mask plating where the
blanket deposition of a second material overlays both the openings
between deposition locations of a first material and the first
material itself.
[0071] FIG. 5 provides a generalized process flowchart of a first
embodiment of the invention which forms a three-dimensional
structure from a conductive material and from a dielectric
material.
[0072] FIG. 6 provides a block diagram of example options that
might be used in association with three of the process operations
of FIG. 5 according to some potential implementations of various
embodiments.
[0073] FIGS. 7(a)-7(j) depict the results of various process stages
associated with the formation of the first two layers of a
particular structure according to a particular implementation of
the embodiment of FIG. 5.
[0074] FIG. 8 provides a generalized process flowchart of a second
embodiment of the invention which modifies a substrate by applying
a conductive material and a dielectric material thereto.
[0075] FIG. 9 provides a generalized process flowchart of a third
embodiment of the invention which forms a three-dimensional
structure from a conductive structural material and from a
dielectric material on at least one layer.
[0076] FIG. 10 provides a generalized process flowchart of a fourth
embodiment of the invention which forms a three-dimensional
structure from a conductive structural material, a conductive
sacrificial material and a dielectric material on at least one
layer.
[0077] FIGS. 11(a) and 11(b) provide block diagrams of example
options that might be used in association with various process
operations of FIG. 10 according to some potential implementations
of various embodiments.
[0078] FIG. 12 provides a generalized process flowchart of a fifth
embodiment of the invention which modifies a substrate by applying
at least two different conductive materials and at least one
dielectric material thereto.
[0079] FIGS. 13(a)-13(j) depict side views of the results of
various process stages associated with the formation of a first
layer of a particular structure according to a particular
implementation of the embodiment of FIG. 10 or of the only layer
that modifies a substrate according to an implementation of the
embodiment of FIG. 12.
[0080] FIGS. 14(a) and 14(b) depict side views of the state of the
process of FIG. 13(j) where the seed layers for each of the
conductive materials is considered to be formed from the conductive
material itself and where FIG. 14(a) depicts the seed layers as
being distinct while FIG. 14(b) depicts the seed layers as being
merged into their respective conductive materials.
[0081] FIG. 15 provides a generalized process flowchart of a sixth
embodiment of the invention which forms a three-dimensional
structure from a conductive structural material, a conductive
sacrificial material, and a dielectric material, wherein at least
one sheet of photoresist material is used in the formation of the
structure.
[0082] FIGS. 16(a)-16(q) schematically depict side views at various
stages of an implementation of a seventh embodiment of the
invention as applied to the formation of a multi-layer
structure.
[0083] FIGS. 17(a)-17(d) schematically depict side views of various
states of an alternative process that involves rolling a
cylindrical support carrying a pattern of ink across a substrate
for transferring the ink to the surface of a substrate in
preparation for depositing layers of a structure on the
substrate.
[0084] FIGS. 18(a)-18(e) schematically depict an alternative
embodiment for transferring a patterned ink from a cylindrical
support to a substrate 2.
[0085] FIGS. 19(a)-19(i) provide schematic depictions of side views
of various stages of a process for forming a multi-layer structure,
using an ink jet deposited mask, as applied to a particular three
layer structure.
[0086] FIGS. 20(a)-20(h) provide schematic side views of various
stages of the process of the fourth embodiment as applied to the
formation of a sample three-dimensional structure.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0087] FIGS. 1(a)-1(g), 2(a)-2(f), and 3(a)-3(c) illustrate various
features of one form 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 various other patents and 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 from the teachings set
forth herein. All of these techniques may be combined with those of
the various embodiments of various aspects of the invention to
yield enhanced embodiments. Still other embodiments may be derived
from combinations of the various embodiments explicitly set forth
herein.
[0088] FIGS. 4(a)-4(i) illustrate various stages in the formation
of a single layer of a multi-layer fabrication process where a
second metal is deposited on a first metal as well as in openings
in the first metal where its deposition forms part of the layer. In
FIG. 4(a), a side view of a substrate 82 is shown, onto which
patternable photoresist 84 is cast as shown in FIG. 4(b). In FIG.
4(c), a pattern of resist is shown that results from the curing,
exposing, and developing of the resist. The patterning of the
photoresist 84 results in openings or apertures 92(a)-92(c)
extending from a surface 86 of the photoresist through the
thickness of the photoresist to surface 88 of the substrate 82. In
FIG. 4(d), a metal 94 (e.g. nickel) is shown as having been
electroplated into the openings 92(a)-92(c). In FIG. 4(e), the
photoresist has been removed (i.e. chemically stripped) from the
substrate to expose regions of the substrate 82 which are not
covered with the first metal 94. In FIG. 4(f), a second metal 96
(e.g., silver) is shown as having been blanket electroplated over
the entire exposed portions of the substrate 82 (which is
conductive) and over the first metal 94 (which is also conductive).
FIG. 4(g) depicts the completed first layer of the structure which
has resulted from the planarization of the first and second metals
down to a height that exposes the first metal and sets a thickness
for the first layer. In FIG. 4(h) the result of repeating the
process steps shown in FIGS. 4(b)-4(g) several times to form a
multi-layer structure are shown where each layer consists of two
materials. For most applications, one of these materials is removed
as shown in FIG. 4(i) to yield a desired 3-D structure 98 (e.g.
component or device).
[0089] Various embodiments of various aspects of the invention are
directed to formation of three-dimensional structures from
materials some of which are to be electrodeposited. Some of these
structures may be formed form a single layer of one or more
deposited materials while others are formed from a plurality of
layers of deposited materials (e.g. 2 or more layers, more
preferably five or more layers, and most preferably ten or more
layers). In some embodiments structures having features positioned
with micron level precision and minimum features size on the order
of tens of microns are to be formed. In other embodiments
structures with less precise feature placement and/or larger
minimum features may be formed. In still other embodiments, higher
precision and smaller minimum feature sizes may be desirable.
[0090] Various embodiments of the invention may perform selective
patterning operations using conformable contact masks and masking
operations, proximity masks and masking operations (i.e. operations
that use masks that at least partially selectively shield a
substrate by their proximity to the substrate even if contact is
not made), non-conformable masks and masking operations (i.e. masks
and operations based on masks whose contact surfaces are not
significantly conformable), and/or adhered masks and masking
operations (masks and operations that use masks that are adhered to
a substrate onto which selective deposition or etching is to occur
as opposed to only being contacted to it). Adhered mask may be
formed in a number of ways including (1) by application of a
photoresist, selective exposure of the photoresist, and then
development of the photoresist, (2) selective transfer of
pre-patterned masking material, and/or (3) direct formation of
masks from computer controlled depositions of material.
[0091] FIG. 5 provides a generalized process flowchart of a first
embodiment of the invention which forms a three-dimensional
structure from a conductive material and from a dielectric
material. The process of FIG. 5 begins with block 102 and then
moves forward to block 104. Block 104 calls for the defining of a
variable "n" to be that of the number of the current layer. It also
calls for the defining of a number "N" which corresponds to a
number of the final layer of the structure to be formed. After the
defining of variables and parameters, the process moves forward to
block 106 which calls for setting of variable "n" to a value of 1.
The process then moves forward to block 108 which calls for the
supplying of a substrate which may include one or more previously
formed layers of material or deposits of material.
[0092] Next the process moves forward to block 112 which calls for
the applying of a dielectric material onto the substrate (or
previously formed layer during a second or subsequent loop through
the process) and the patterning of the dielectric according to a
design for layer n. The application of the dielectric and the
patterning of the dielectric may occur in a variety of ways which
will be discussed hereinafter.
[0093] From block 112 the process moves forward to block 114 which
calls for the supplying of a seed layer. In some implementations of
the current embodiment, the seed layer is applied in a blanket
fashion such that the seed layer material is applied on the
dielectric material, on the exposed portions of the substrate (or
previously formed layer during a second or subsequent loop through
the process) within the voids formed by the patterning of the
dielectric material, on the side walls of the dielectric material
surrounding the voids, and on the outward facing (e.g. upward or
down-ward facing) surface of the dielectric material). In some
alternative embodiments, the seed layer may be applied in a
selective manner (e.g. where all pockets remain conductively
connected but where seed layer material is not necessarily located
over all portions of the dielectric material). Some examples of
seed layer applying processes for various implementations of the
current embodiment will be discussed hereinafter in association
with FIG. 6.
[0094] From block 114 the process moves forward to block 116 which
calls for the deposition of a conductive material. The effective
deposition of conductive material will result in the conductive
material being deposited on the seed layer coated portions of the
substrate (or previously formed layer during a second or subsequent
loop through the process) that were exposed via the voids in the
dielectric material.
[0095] From block 116 the process moves forward to block 118 which
calls for the planarization of the deposits. In some
implementations of the present embodiment, successful planarization
will be that which produces a layer having various distinct
regions, e.g. dielectric regions separated from conductive material
regions which are surrounded on the sides and substrate/previous
layer interface by seed layer material, and possibly an adhesion
layer material and/or other material layers providing desired
properties (diffusion barrier properties, etching barrier
properties, and the like). Successful planarization will result in
the removal of any seed layer material and possibly adhesion layer
material and/or other material layers that exist over the
dielectric material. This planarization process preferably sets the
boundary height of the deposited material to correspond to a
boundary of layer "n", or in other words set the deposition level
to a height equal to that of the layer thickness, LT. The
planarization process completes the formation of layer n.
[0096] From block 118 the process moves forward to block 122 which
calls for incrementing the current layer variable, n, by 1. After
block 122, the process moves forward to decision block 124 which
inquires as to whether or not variable "n" is greater than N. If
the answer is "yes", it implies that formation of all layers of the
structure have been completed and the process moves forward to
ending block 126. If the inquiry of block 124 produces a negative
response, the process loops back to block 112 so that a next layer
may be formed.
[0097] The various operations of the embodiment of FIG. 5 result in
the formation of layered structures that include conductive
material, seed layer material and dielectric material. The layered
structures may also include adhesion promoting materials, barrier
materials, and the like. In these embodiments, seed layer material
exists between regions of conductive material located on
consecutive layers. On the other hand, dielectric material
deposited on one layer is not separated from overlaying dielectric
material deposited on an adjoining layer by a seed layer material.
The structure may be put to use after formation of the layers, or
alternatively, a variety of post processing operations may be
performed on the layered structure for a variety of reasons and in
a variety of ways.
[0098] For example, post processing operations may include one or
more of (1) forming additional layers using other techniques then
those set forth in FIG. 5, (2) the dicing of structures from other
structures that were formed simultaneously, (3) the releasing of a
formed structure from any sacrificial material that was used during
formation of the structure, e.g. removing the dielectric material
to release a structure of conductive material, or removing the
conductive material to release a structure of dielectric material,
(4) separating the structure from a substrate on which it was
built, (5) attaching the structure to another substrate or
attaching additional components or elements to the structure, (6)
coating the structure with any desired material, (7) smoothing of
layer-to-layer discontinuities, (8) performing any desired
annealing operations, (9) performing any desired diffusion bonding
operations, (10) performing any desired sealing operations, or (11)
any desired interfacing operations with other components,
structures, devices, and the like.
[0099] In some variations of the embodiment, the final structure
produced according to the process of FIG. 5, may be a combined
structure of the conductive material, the seed layer material and
the dielectric material. In other variations, the final structure
may be the conductive material and seed layer material with the
dielectric material removed. In still other variations, the
structure of conductive material separated from the dielectric
material with which it was formed may be partially or completely
encapsulated in or partially or completely filled with a different
dielectric material. In still other variations, the final structure
may be the dielectric material itself with the conductive and seed
layer materials removed. In even further variations, the structure
of dielectric material separated from the conductive material with
which it was formed may be partially or completely encapsulated in
or partially or completely filled with a different conductive
material.
[0100] FIG. 6 provides a block diagram of some examples of options
or operations that might be used in association with three selected
process operations of FIG. 5 according to various alternative
embodiments of the invention.
[0101] In particular, FIG. 6 provides example operations that may
be performed when implementing each of (1) the dielectric material
application operation of block 112 of FIG. 5, (2) the seed layer
supplying operation of block 114 of FIG. 5, and (3) the conductive
material deposition operation of block 116 of FIG. 5.
[0102] Operation 112 may be implemented by applying a dielectric
material in sheet form as indicated by block 202. As indicated in
block 204, the sheet may then be selectively exposed and developed
(e.g. when using a negative or positive dry film photoresist
material) to pattern the material. Alternatively, as indicated in
block 206, portions of the sheet may undergo selective ablation to
pattern it.
[0103] In still other alternative implementations, as indicated by
block 208, operation 112 may be performed by applying a liquid
material to the substrate. The application, curing, and patterning
of the liquid material may occur in a variety of ways. For example,
as indicated by block 210, the liquid material may be applied and
then solidified and then patterned. In such implementations, as
indicated in blocks 212 and 214, the patterning operation may, for
example, be similar to the exposure and developing operations of
block 204 or the ablation operation of block 206. In still other
alternatives, as indicated in block 216, the liquid material may be
selectively solidified and patterned at the same time (e.g. using a
selectively exposed photopolymer). In a further alternative, as
indicated by block 218, the application of the liquid material may
occur simultaneously with patterning such as by selectively
dispensing of a material onto the substrate, for example, via an
ink jetting or extrusion process where the jetted or extruded
material may be dispensed in a melted form which solidifies upon
cooling, it may be photocurable whereby after or during dispensing
it is exposed to appropriate radiation, or it may be thermally
curable whereby after dispensing the material is raised to an
appropriate temperature to cause solidification, for example, to
cause polymerization or another chemical reaction that results in
cohesion.
[0104] In another alternative, as indicated by block 222, the
dielectric material may be transferred in a prepatterned manner,
e.g. by a transfer tool such as a patterned transfer plate. As
indicated in block 224 by transferred material may be in a liquid
or flowable form which is made to solidify and adhere to the
substrate or it may be in a substantially solidified state, In
still further alternatives, the masking material may be transferred
in a prepatterned and solidified state as indicated by block 232,
upon transfer but which is made to adhere to the substrate upon or
subsequent to transfer, e.g. by pressure, use of an adhesive,
oxygen removal, heating, and the like. In even further
alternatives, as indicated in block 228, the masking material may
be applied into openings in a pre-applied or formed patterning
material that is on the substrate or previously formed layer, after
application of the masking material the patterning material may be
removed. In one alternative, as indicated in block 230, after
application of the masking material and prior to removal of the
patterning material, the two materials may be planarized and then
the patterning material removed by, e.g. selective etching or
dissolution.
[0105] The seed layer supplying operation 114 may be implemented in
a variety of different ways, for example, by physical vapor
deposition, chemical vapor deposition, electroless plating, an
electroplating strike process (e.g. a Woods nickel strike), and/or
direct plating or metallization. Direct plating may take several
forms: (1) using the Futuron.TM. process of Atotech Deutschland
GmbH, Berlin, Germany; (2) using the Envision DPS process of
Enthone-OMI; (3) using the Connect Process of M & T; (4) using
the Black Hole process of the Hunt Company; (5) using the Black
Hole II process of MacDermid Co.; (6) using the Shadow process of
the Electrochemicals Inc., Maple Plain, Minn., USA; (7) using the
Graphite 200 process of Shipley Company, L.L.C., Marlborough,
Mass., USA; (8) using the SMS-E process of Blasberg Co., Germany;
or (9) the Compact CP process of Atotech Skandinavien AB, or the
like.
[0106] In some implementations, as indicated by block 242, the seed
layer material may be the same material as the conductive material.
In other implementations, as indicated by block 244, the seed layer
may be accompanied by one or more other materials which may provide
adhesion enhancing properties, diffusion limiting properties,
etching barrier properties, other desired transitional properties,
or the like. When using a seed layer in combination with an
adhesion layer, for example, they both may be applied by sputtering
with the adhesion layer being applied first and the seed layer
being applied second. In some embodiments, an adhesion layer and a
seed layer may be applied during the same vacuum operation to avoid
having the adhesion layer become passivated prior to coating it
with the seed layer material. In still other embodiments,
application of an adhesion layer may be followed by application of
a seed layer with various operations occurring there between. For
example, one of the materials may be an adhesion enhancing material
such as titanium, chromium, or titanium tungsten, or the like. The
seed layer material may be sputtered copper, sputtered nickel,
nickel from a strike, electroless copper, electroless nickel,
sputtered gold, and the like, which may provide a transition layer
material that allows improved electroplating ability or the like.
In some embodiments, a seed layer material may be over coated with
another material that provides a barrier or other transitional
properties between it and the bulk of a conductive material that
will be used in building up layers.
[0107] The use of a multi-material seed layer stack (e.g. an
adhesion layer and a seed layer) may be provided in different ways.
For example, as indicated by block 246, the first material may
provide an adhesion layer and the second material may be the same
as the conductive material that is to be deposited. Alternatively,
as indicated in block 248, the first material may provide an
adhesion layer and the second material may be different from the
conductive material that is to be deposited.
[0108] In a further alternative, as indicated in block 250,
operation 114 may be implemented by using a single material that is
deposited as a thin layer where the material is different from the
conductive material that will be deposited over it. The
implementation of operation 114 preferably results in formation of
a very thin coating that will (1) allow subsequent
electrodeposition or other deposition operations to occur, (2)
provide adequate adhesion between the conductive material and the
dielectric material, (3) allow the deposition of the conductive
material in a desired manner, and (4) not significantly negatively
impact the desired mechanical, electrical, or thermal properties of
the structure.
[0109] In some embodiments of the invention, it may be desirable to
remove the seed layer material from the sidewalls of the conductive
material. This removal may occur via an etching operation, after
deposition of the conductive material and removal of the masking
material on which the seed layer material was deposited. To ensure
that interlayer adhesion is not undermined by such etching, the
seed layer or seed layer stack is preferably as thin as possible,
for example, in some embodiments an adhesion layer material may
have a thickness in the range of 50-1000 angstroms, more or less,
and is preferably in the range 100-500 angstroms, while the seed
layer itself may have a thickness in the range of 0.1-1.0 microns,
more or less, and more preferably about 0.2-0.5 microns.
[0110] The deposition of a conductive material as called for by
block 116 may be implemented in a variety of ways. For example, via
blanket or selective electroplating (block 262), via blanket or
selective electroless plating (block 264), via spraying such as
thermal spraying of metal (block 266), via blanket or selective
electrophoretic deposition (block 268), and/or via a physical vapor
deposition technique (block 270), or the like.
[0111] FIGS. 7(a)-7(j) depict schematic representations of side
views of the results of various process stages associated with the
formation of the first two layers of a particular structure
according to a particular implementation of the embodiment of FIG.
5. FIG. 7(a) depicts a substrate 302 overlaid by a uniform coating
or sheet of a dielectric material 304-1. It should be understood
that substrate 302 may include previously formed layers of material
and that it may or may not have a surface that is entirely
conductive (e.g. the whole or a portion of the surface may be
dielectric, semi conductive, conductive, or some combination
thereof).
[0112] FIG. 7(b) depicts the state of the process after dielectric
material 304-1 has been selectively patterned to reveal voids 310
in the dielectric that expose portions of a surface of substrate
302. FIG. 7(c) depicts the state of the process after formation of
a seed layer 306-1. FIG. 7(d) shows the state of the process after
a blanket deposition of a conductive material 308-1 fills the
voids.
[0113] FIG. 7(e) depicts the state of the process after the
formation of the first layer is completed as the result of a
planarization operation that trims the height of the deposited
materials to that of a first layer thickness LT. The first layer
includes regions of (1) dielectric material 304-1 and (2)
conductive material 308-1 which are surrounded on the substrate and
dielectric sides by seed layer material 306-1.
[0114] FIGS. 7(f)-7(j) depict states of the process associated with
the formation of a second layer. The states of the process during
formation of the second layer are similar to those shown in FIGS.
7(a)-7(e) for the first layer. FIG. 70) depicts the state of the
process after completed formation of the second layer. The second
layer includes regions of (1) dielectric material 304-2 and (2)
conductive material 308-2 bounded on the substrate and dielectric
sides by seed layer material 306-2.
[0115] Though FIGS. 7(a)-7(j) depict the formation of only the
first 2 layers of a structure, it is clear that the structure may
include additional layers for which the process operations may be
repeated so as to build up a taller and potentially more complex
structure. It should be understood that in some embodiments other
operations may be used to form some layers of the structure. Some
alternative operations for other implementations of embodiments of
the invention will be discussed herein later.
[0116] FIG. 8 provides a generalized process flowchart of a second
embodiment of the invention which modifies a substrate by applying
a conductive material and a dielectric material thereto.
[0117] The embodiment of FIG. 8 is similar to that of FIG. 5 with
the exception that it calls for the formation of a single layer of
material on a substrate. Operations 402, 408, 412, 414, 416, 418
and 426 correspond essentially and respectively to operations 102,
108, 112, 114, 116, 118 and 126 of FIG. 5.
[0118] FIG. 9 provides a generalized process flowchart of a third
embodiment of the invention which forms a three-dimensional
structure from a conductive material and from a dielectric
material. The embodiment of FIG. 9 is similar to that of FIG. 5
with the exception that it contemplates the possibility that some
other generalized process may be used to form one or more of the
layers of the structure. In FIG. 9 similar operations to those
shown in FIG. 5 are indicated with equivalent reference numbers.
The process of FIG. 9 and that of FIG. 5 proceed in similar manners
up through operation 108 after which the process of FIG. 9 moves
forward to decision block 130 where an inquiry is made as to
whether or not layer "n" is to be formed using a single dielectric
and a single conductive material.
[0119] If this inquiry produces a positive response the process
proceeds along a path that implements elements 112-124 in a manner
analogous to that of the embodiment of FIG. 5. If decision block
130 produces a negative response, the process moves forward to
block 132 which calls for the formation of layer "n" in a desired
manner but presumably a different manner than that called for by
blocks 112-124. From block 132 the process moves to block 122 then
to block 124 which have been previously discussed. A negative
decision from block 124 loops the process back to block 130 while a
positive response moves the process forward to block 126 which ends
the layer formation process as all layers have been formed. In some
alternative embodiments, even if the next layer to be formed is
formed with a single conductive material and a single dielectric, a
process different than that set forth by operations 112-124 may be
used.
[0120] The formation of layer "n" in an alternative manner as
called for by block 132 may occur in a variety of different ways.
The processing of layer "n" in this alternative manner may in part
be dictated by the materials to be deposited on layer "n" as well
as possibly the exact configuration of layer "n" compared to that
of the previous layer. For example, if layer "n" does not include a
dielectric material but layer "n-1" did, layer "n" may need to have
a conductive sacrificial material and a conductive structural
material deposited but it may also need to have a seed layer
deposited as well. It may also need an adhesion layer to be
applied. If layer "n-1" was formed from only conductive materials,
there may be no need to use a seed layer when forming layer "n"
even if layer "n" includes a dielectric material. Various other
layer formation processes may be implemented in association with
block 132 and will be understood by those of skill in the art in
some of these alternatives the formation processes need not be
limited to electrochemical fabrication methods.
[0121] In some alternative processes, each layer of the structure
may be formed using a conductive structural material, a conductive
sacrificial material, and a dielectric material. In one such
alternative embodiment, an adhesion layer and an overlying seed
layer may be applied to a previous layer, a selective deposition of
either a conductive structural material or a conductive sacrificial
material may occur, portions of the seed layer and adhesion layer
that have not received the initial deposit of conductive material
may be removed, for example, by chemical or electrochemical
etching. Next an additional adhesion layer (if necessary) and an
additional seed layer material may be deposited. The adhesion layer
material and/or seed layer material may be different from the
initial adhesion layer and seed layer materials. In some
embodiments they may be specifically selected for their
compatibility with the second conductive material to be deposited.
One or both of the adhesion layer and seed layer materials that
underlie sacrificial material are preferably removable along with
the sacrificial material while the adhesion layer and seed layer
materials underlying structural material are preferably not
significantly damaged by the removal of the sacrificial material.
In this alternative layer forming process, as described above, the
removal of the second seed layer material, and possibly adhesion
layer material, located on the deposits of the first deposited
conductive material may occur via a planarization operation or the
like. In embodiments where the second deposited conductive material
occurs in a selective manner and thus does not overlay the regions
where the first deposited conductive material exist, removal of any
seed layer material, and possibly adhesion layer material from
above the first conductive material may occur via an etching
operation or the like. In this alternative process, dielectric
material desired on selected layers may be deposited and patterned
prior to deposition of the first adhesion and seed layer materials,
after deposition of the first conductive material and prior to
deposition of the second adhesion and seed layer materials, or
after deposition of the second conductive material. In some
alternative embodiments, selective etching operations may be used
to create voids in which the dielectric material or second
conductive material may be located.
[0122] FIG. 10 provides a generalized process flowchart of a fourth
embodiment of the invention which forms a three-dimensional
structure from a conductive structural material, a conductive
sacrificial material and a dielectric material on at least one
layer.
[0123] The process set forth in the flowchart of FIG. 10 begins at
element 502 and from there proceeds to block 504. Block 504 calls
for the defining of a variable "n" to be equal to the number of the
current layer being processed. It also defines a value "N" as the
number associated with the final layer of the structure.
[0124] From block 504 the process moves forward to block 506 which
calls for setting "n" to a value of one. From block 506 the process
moves forward to decision block 508 which inquires as to whether or
not layer "n" is to be formed using a single dielectric material, a
single conductive structural material and a single conductive
sacrificial material. A negative response to this inquiry of block
508 sends the process forward to block 512 which calls for the
formation of the layer in any desired manner. The desired manner
may be one of the alternatives discussed above with regard to block
132 of FIG. 9 or it may be some other manner which may have been
described hereinbefore or hereinafter or set forth in one of the
applications incorporated herein by reference or be based on a
combination of those teachings or simply be known to those of skill
in the art.
[0125] From block 512 the process moves forward to block 514 which
will be discussed herein later. A positive response to block 508
sends the process forward to block 518. Block 518 calls for the
applying and patterning of a dielectric onto a substrate or
previously formed layer where the applying and patterning result in
those portions of the substrate being exposed where a first
conductive material is to be deposited which may be of the
structural or sacrificial type.
[0126] From block 518 the process moves forward to block 522 which
calls for the depositing of a seed layer (and possibly of an
additional one or more materials, e.g. an adhesion layer) that is
appropriate for use with the first conductive material that is to
be deposited. After formation of the seed layer, the process moves
forward to block 524 which calls for deposition of the first
conductive material.
[0127] From block 524 the process moves forward to block 526 which
calls for planarizing of the partially formed layer to a height
equal to the layer thickness plus an extra amount (e.g. two times
an incremental amount .delta.). Such a planarization height may be
selected as it allows multiple additional planarization operations
to occur with each being separated from the other by an amount
.delta., or more, where the amount .delta. is equal to or larger
than a tolerance associated with each planarization operation. Such
multiple planarization operations during the formation of a single
layer are preferred in the present embodiment as they enhance the
accuracy of the structures being formed. However, in various
alternate embodiments it may be possible to vary the planarization
height and to vary the number of planarization operations used
during the formation of a given layer.
[0128] From block 526 the process moves forward to decision block
528 which inquires as to whether or not the dielectric material can
be further patterned. If this inquiry produces a negative response,
the process moves forward to block 530 which calls for the removal
of the dielectric. This removal process may occur in a variety of
ways depending on the type of dielectric material present. For
example, if the dielectric material is a photoresist, standard
techniques associated with the stripping of photoresist may be
used.
[0129] From block 530 the process moves forward to block 532 which
calls for the application and patterning of a dielectric material
on the substrate or previously formed layer and potentially onto
the first deposited conductive material. The patterning exposes
those portions of the substrate where a second of the conductive
materials is to be located. The patterning may also result in a
surface of the first deposited conductive material being exposed.
Such exposure will be without detriment as later in the process a
planarization operation will be used to remove any material
deposited onto the first conductive material.
[0130] From block 532 the process moves forward to block 536 which
will be discussed herein later. A positive response to the inquiry
of decision block 528 causes the process to move forward to block
534 which calls for the patterning of the dielectric to expose
regions where the second of the conductive materials is to be
deposited.
[0131] From block 534, the process moves forward to block 536.
Block 536 calls for the deposition of a seed layer that is
appropriate for use with the second conductive material that is to
be deposited. The seed layer may be part of a seed layer stack that
includes one or more additional materials which may be deposited
before the seed layer or after the seed layer (e.g. it may be
preceded by the deposition of an adhesion enhancing layer).
[0132] From block 536 the process moves forward to block 538 which
calls for the deposition of the second conductive material. Further
discussion concerning the operations of blocks 518-536 will be
provided hereinafter in association with the discussion of FIGS.
11(a) and 11(b).
[0133] From block 538 the process moves forward to decision block
540 which inquires as to whether or not the patternable dielectric
is a structural material or at least a material that will remain as
part of the formed layer. A positive response to this inquiry
causes the process to move forward to block 550 which will be
discussed hereinafter but a negative response to the inquiry causes
the process to move forward to block 544. Block 544 calls for the
planarization of the partially formed layer to a level equal to the
layer thickness plus an incremental amount .delta..
[0134] From block 544 the process moves forward to block 546 which
calls for the removal of the patternable dielectric and thereafter
the process moves forward to block 548 which calls for the
deposition of the desired structural dielectric material.
[0135] From block 548, as with block 540, the process moves forward
to block 550 which calls for a planarization of the layer to a
level which is intended to bound the layer or in other words to a
height equal to that of the layer thickness.
[0136] From block 550 as with block 512 the process moves forward
to block 514 which calls for incrementing the layer number
variable, "n", by one.
[0137] From block 514 the process moves forward to decision block
516 which inquires as to whether or not "n" has exceeded the final
layer number. If a positive response is provided by this inquiry,
it means that all layers of the structure have been formed and the
process moves forward to end block 552. On the other hand if the
inquiry produces a negative response, the process loops back to
block 508 so that a next layer of the structure may be formed.
[0138] As with the previously discussed processes, after formation
of all layers of the structure, various post processing operations
may be performed. In particular as one of the deposited conductive
materials is a sacrificial material it is anticipated that that
sacrificial material will be removed at some point during post
processing operations but it is conceivable that in some
applications the sacrificial material may be removed during use of
the structure as opposed to during a pre-use post processing
operation.
[0139] FIGS. 11(a) and 11(b) provide block diagrams of example
options that might be used in association with various process
operations of FIG. 10 according to some potential implementations
of some embodiments.
[0140] FIG. 11(a) provides some examples of variations that are
possible for use in implementing operations 518, 522, and 524 of
the process of FIG. 10. To a large extent the various alternative
implementations of FIG. 11(a) are analogous to those set forth in
FIG. 6 concerning example variations of implementations associated
with the process of FIG. 5. As such many of the blocks of FIG.
11(a) have been identified with identical reference numerals to
those used in association with FIG. 6. As those particular
alternatives have already been discussed in association with FIG.
6, they will not be discussed herein at this time, but instead the
reader is directed to the discussion set forth above concerning
FIG. 6. However, FIG. 11(a) does include some additional
implementation alternatives which result from the fact that two
conductive materials are being used on at least some layers and
more particularly due to the fact that one of the conductive
materials is a structural material while the other is a sacrificial
material. In particular, the operation of block 246 has two options
associated with it. Similarly the operation alternative associated
with block 248 has two options associated with it.
[0141] Block 246 calls for use of a seed layer stack where an
initial material provides an adhesion layer and where a
subsequently deposited seed layer material is the same as the first
conductive material to be deposited.
[0142] Block 612 sets forth a first option which is based on the
first conductive material being the sacrificial material (SACMAT).
In this case, the adhesion layer (AL) material (ALM) is preferably
selected such that it is removable from (1) the structural material
(STRMAT) and (2) any structural material seed layer (SL) or seed
layer stack without significantly damaging them when it is removed.
This preferred property of the adhesion layer relative to the other
materials may not be necessary with regard to all the other
materials in the build but instead only to those that the object
geometry or process bring into contact with the particular adhesion
layer material. For example, the adhesion layer material for the
sacrificial material may be the same as that for the structural
material and portions of the two seed layer materials may contact
one another but in critical regions (e.g. between structural
material on the present layer and structural material on the
previous layer) geometric considerations (e.g. the thinness of the
adhesion layer and the associated lack of access to attack it) make
the use of the selected adhesion layer material acceptable. Similar
considerations to those set forth here may apply in various ways to
the other embodiments set forth herein and in some circumstances
they may apply to seed layer materials as well.
[0143] Block 614 sets forth an option that is appropriate to use
when the first conductive material is the structural material. It
calls for the adhesion layer material being selected such that it
will not be significantly damaged by the removal of sacrificial
material or an associated seed layer material. More particularly,
it is the adhesion layer material located between the structural
material of the present layer and material on the previous layer
that should not be damaged. Minimization to damage of this
sandwiched adhesion layer material may result from an inertness of
the adhesion layer material to the etchant or etching process used
to remove the sacrificial material or it may simply result from the
thinness of the adhesion layer material and the inability of the
etchant to effectively attack it. It may or may not be relevant if
any adhesion layer material located on a sidewall of the structural
material is removed. If necessary, such removal may be accommodated
for by an adjusting of the size of layer feature regions based on
the processing that will be used in fabricating the structure. Such
size adjustments may be made empirically, theoretically, manually,
or automatically by appropriate programming of data manipulation
and/or control software or they may be made by redesigning the
structure so that the final size (after removal of the adhesion
layer material) is the desired size. It is believed that in most
circumstances such adjustment will not be warranted due to the
typical thinness of the adhesion layer.
[0144] Block 248 calls for the use of a seed layer material stack
where an initial material provides an adhesion layer and a
subsequent material provides the seed layer which is different from
the conductive material that is to be deposited.
[0145] Block 616 sets forth an option that is appropriate when the
conductive material to be deposited is the sacrificial material. In
such cases the seed layer stack materials are preferably selected
so as to be removable without significantly damaging any exposed
structural material, any exposed structural material seed layer
material or seed layer stack materials (particularly those involved
in adhering layers to one another), or any other exposed materials
associated therewith.
[0146] Block 618 sets forth an option that is appropriate when the
conductive material to be deposited is the structural material. In
such cases the seed layer material or seed layer stack of
materials, to the extent that they will be exposed to sacrificial
material and sacrificial seed layer material etchants, should be
selected so that they are not significantly damaged by the removal
of the sacrificial material or its associated seed layer material
or other associated materials (e.g. adhesion layer or barrier layer
materials).
[0147] FIG. 11(b) sets forth examples of some alternative
implementations for operations 530, 532, 536 and 534 of FIG. 10. In
particular operation 530 which calls for the removal of the
dielectric material may be implemented for example by ablating the
dielectric (block 622), developing or dissolving the dielectric
material (block 624), melting and removing the dielectric material
possibly with the aid of vacuuming it up or blowing it off (block
626), or by exposing the material to radiation to break polymer
bonds and thereafter dissolving or melting the material (block
628).
[0148] Examples of alternative implementations for the applying and
patterning operations of block 532 as indicated by block 632 are
similar to those associated with the applying and patterning
operations of block 518 as set forth in FIG. 11(a).
[0149] Examples of alternative implementations for the depositing
of a seed layer, or seed layer stack, as set forth in block 536 are
analogous to the alternatives set forth in FIG. 11(a) for the seed
layer depositing operation 522.
[0150] Examples of alternative implementations for the dielectric
patterning operation of block 534 include the selective exposure
and development of the dielectric, for example, when it is a
photoresist material (block 642) or via the selective ablation of
the dielectric material (block 644).
[0151] FIG. 12 provides a generalized process flowchart of a fifth
embodiment of the invention which modifies a substrate by applying
at least two different conductive materials and at least one
dielectric material thereto.
[0152] The embodiment of FIG. 12 is similar to the embodiment of
FIG. 10 with the exception that as illustrated the embodiment of
FIG. 12 forms a single layer and thus provides a single build
process for the formation of that layer as opposed to providing an
alternative build process for use on some layers as block 512 of
FIG. 10 did.
[0153] Blocks associated with the operations of FIG. 12 have been
labeled with identical reference numerals as their corresponding
blocks in FIG. 10.
[0154] Various other alternatives to the processes of FIGS. 10 and
12 are possible. For example, not all layers (of a multi-layer
embodiment) may include each of the three materials. In such
processes additional decision points may be added to remove
consideration of unnecessary operations from the process on those
layers (see for example the flowchart of FIG. 15 to be discussed
hereafter). In addition, for example, if a given layer did not
include a conductive sacrificial material, the process may skip all
operations from 526 to 538 (in other words the process may skip
from block 524 directly to block 540). As another example, if some
layers do not include a structural dielectric material, the process
may flow from block 524 to a planarization operation like that of
526 but where the level of planarization would be LT+6 and
thereafter the process might move forward to block 530, and then
directly from block 530 to block 536 or even block 538 depending on
what material types exist and also potentially on their positioning
on the previous layer, layer "n-1". The process then might skip
from block 538 directly to block 550. It will be understood by
those of skill in the art that many additional alternative
processes are possible including those with fewer decision blocks
and those with more decision blocks as well as those with fewer or
more operations, those with different operations, and those with
operations that have a different order and thus take on somewhat
different features.
[0155] FIGS. 13(a)-13(j) schematically depict side views of the
results of various process stages associated with the formation of
a first layer of a particular structure according to a particular
implementation of the embodiment of FIG. 10. Alternatively, FIGS.
13(a)-13(j) may be considered to schematically depict side views of
the results of various process stages associated with the
modification of the substrate according to an implementation of the
embodiment of FIG. 12.
[0156] FIG. 13(a) depicts the state of the process after supplying
a substrate 702 while FIG. 13(b) depicts the state of the process
after formation of a dielectric coating or application of a
dielectric sheet 704 to the surface of substrate 702.
[0157] FIG. 13(c) depicts the state of the process after dielectric
coating 704 has been patterned to form voids 710 that expose
selected portions of the surface of substrate 702.
[0158] FIG. 13(d) depicts the state of the process after a seed
layer 706 has been deposited onto the dielectric 704 and into the
voids or valleys in the dielectric material that extend and cover
the surface of a substrate. The dielectric material is selected to
be appropriate for the conductive material which is shown as having
been deposited in FIG. 13(e). In some alternative embodiments the
seed layer may be replaced by a multi-material seed layer
stack.
[0159] Next a planarization operation occurs which trims the
surface of the deposited materials to a height of one layer
thickness or more preferably to a height slightly greater then one
layer thickness. This planarization process removes the conductive
material 708 and the seed layer material 706 that overlays the
dielectric material as shown in FIG. 13(f). Next a second
dielectric material patterning operation is performed to open up
locations where a second conductive material is to be deposited.
This patterning operation produces voids 720 in the dielectric
material as shown in FIG. 13(g).
[0160] Next a seed layer appropriate for use with the second
conductive material to be deposited is applied as indicated by
reference numeral 716 in FIG. 13(h).
[0161] Next the second conductive material 718 is deposited in a
blanket fashion as indicated in FIG. 13(i) and thereafter the
deposited materials are planarized to a net effective height of one
layer thickness. The planarization operation removes the second
conductive material that overlays both the dielectric material and
the first conductive material and also removes the seed layer
material that overlaid the dielectric material and the first
conductive material as shown in FIG. 130).
[0162] FIGS. 14(a) and 14(b) depict side views of the state of the
process of FIG. 13(j) where the seed layers for each of the
conductive materials are considered to be formed from the
conductive materials themselves. FIG. 14(a) depicts the seed layers
as being distinct while FIG. 14(b) depicts the seed layers as being
merged into their respective conductive materials.
[0163] FIG. 15 provides a generalized process flowchart of a sixth
embodiment of the invention which forms a three-dimensional
structure from a conductive structural material, a conductive
sacrificial material, and a dielectric material, wherein sheets of
photoresist material are used in the formation of the structure.
The process of FIG. 15 does not require each of the three materials
to exist on each layer and as such, the flowchart includes decision
blocks that allow some operations to be skipped.
[0164] The process of FIG. 15 begins with element 802 after which
it moves forward to block 804 which calls for the application of a
photoresist coating or sheet to a substrate after which the process
moves forward to block 806 which calls for the patterning of the
photoresist such that regions on the substrate where a first
conductive structural or sacrificial material is to be located are
exposed.
[0165] From block 806 the process moves forward to block 808 which
calls for the deposition of an appropriate seed layer for the first
material. Next the process moves forward to block 810 which calls
for the deposition of a first material.
[0166] Next the process moves forward to decision block 812 which
inquires as to whether a second conductive material is to be
deposited. If the response is "no" the process moves forward to
block 832 which inquires as to whether or not a dielectric material
is going to be used as part of the final structure. If a positive
response results from this inquiry the process moves to block 830
which will be discussed further herein later. If a negative
response results from this inquiry, the process moves forward to
block 852 which calls for the planarization of the layer to a
height equal to that of the layer thickness after which the process
moves forward to block 854 which calls for the removal of the
photoresist. Then the process moves forward to block 846 which will
be discussed herein later. The flow from blocks 812 to 832 to 852
and to 854 result in the formation of a layer or partial layer from
a single material.
[0167] If the inquiry of block 812 produces a positive response,
the process moves forward to block 814 which calls for planarizing
the deposited material and photoresist to a height equal to the
layer thickness plus twice an incremental amount .delta. (where
.delta. is equal to or greater than a tolerance associated with the
planarization operation). Next the process moves forward to
decision block 816 which inquires as to whether or not the
photoresist may be further patterned. If the answer to this inquiry
is "no" the process moves forward to block 818 which calls for the
removal of the photoresist then to block 822 which calls for
reapplication of photoresist after which the process moves forward
to block 824. If the inquiry of block 816 produces a positive
response the process moves forward, as it did from block 822, to
block 824. Block 824 calls for the patterning of the photoresist
material to expose those regions where a second conductive material
is to be located. This patterning operation may also expose, leave
exposed, or leaved covered regions on the first conductive material
as any deposits above the first conductive material will eventually
be planarized in any event.
[0168] From block 824 the process moves forward to block 826 which
calls for the deposition of a seed layer which is appropriate for
use with the second conductive material. From block 826 the process
moves forward to block 828 which calls for the deposition of the
second conductive material.
[0169] From block 828 the process moves forward to decision block
832 as it did from a negative response to the inquiry of block 812.
A negative response to the inquiry of block 832 causes the process
to move to block 852 as discussed previously.
[0170] A positive response to the inquiry of decision block 832
sends the process to decision block 830 which inquires as to
whether the photoresist material is the dielectric structural
material. A positive response to this inquiry causes the process to
move forward to block 844 which will be discussed herein later,
whereas a negative response to this inquiry causes the process to
move forward to block 836 which calls for the planarization of the
partially formed layer to a height equal to that of the layer
thickness, LT, plus an incremental amount .delta..
[0171] From block 836, the process moves forward to block 838 which
calls for the removal of the photoresist material and then on to
block 842 which calls for the deposition of a desired dielectric
structural material. From block 842, as from a positive inquiry
from block 830, the process moves forward to block 844 which calls
for the planarization of the deposited materials to a height equal
to that of the layer thickness, LT.
[0172] From block 844 the process moves forward to decision block
846 as it did from block 854. Block 846 inquires as to whether the
just formed layer was the last layer. A positive response to this
inquiry sends the process to block 858 which ends the process
whereas a negative response to this inquiry directs the process
back to block 804 so that one or more additional layers may be
added.
[0173] Various alternatives to the embodiments described above are
possible. For example, in embodiments where the substrate is
conductive or where the previously formed layer is sufficiently
conductive, it may not be necessary to use a first seed layer since
deposition into the voids in the dielectric may be possible without
the seed layer. In these embodiments sufficient conductivity of the
substrate or previously formed layer may be defined in different
ways. For example, sufficient conductivity may be defined to exist
only when all regions where the first conductive material is to be
deposited overlay conductive material and wherein conductive paths
in the previous layer or substrate connect all the separate regions
together or to external contact regions where electrical contact
between the structure, substrate, or previous layer will be
made.
[0174] In other embodiments, sufficient conductivity may be defined
to exist when conductive material exists on the substrate or
previously formed layer in most locations where conductive material
is to be deposited and where depositions to those conductive
regions will bridge gaps (i.e. via mushrooming) across dielectric
material to completely fill in the voids or to connect separated
conductive regions together. In other words, in some embodiments
sufficient conductivity may be considered to exist even though
small gaps of dielectric material exist or relatively small regions
of dielectric must be initially bridged by the in-plane spreading
of the conductive material which can be made to occur in a timely
manner and in the effective manner for yielding depositions of
desired configuration and height.
[0175] In other embodiments it may be possible to work with a
single dielectric and single conductive material (e.g. structural
or sacrificial material) on some layers while on other layers it
may be possible only to work with structural and sacrificial
conductive materials.
[0176] In still other embodiments more than one conductive
structural material may be used, more than one conductive
sacrificial material may be used, and/or more than one dielectric
structural or sacrificial material may be used. The extension of
the dielectric repatterning operations, dielectric removal and
replacement and repatterning operations, and the seed layer
application operations to third, fourth, or even more materials,
may involve a simple extension of the techniques used in preparing
to deposit the second conductive material. Selected additional
patterned dielectrics may be deposited without a need to
pre-deposit a seed layer.
[0177] In still other embodiments data processing and masking
techniques may be used to limit seed layer formation to occur only
over dielectric material or such that it overlays conductive
material only slightly such that dielectric material is not located
between successive layers of conductive structural material and/or
between successive layers of conductive sacrificial material.
[0178] In still other embodiments it may be possible to place seed
layer material only over dielectric material and to leave a zero
gap or slight gap between the conductive material and the seed
layer material where such a gap can be readily bridged during
plating operations to cause deposited conductive material to
overlay the conductive material regions on the previous layer as
well as to overlay seed layer regions on the present layer.
[0179] In still other embodiments, the definition of which material
is the first conductive material and which material is the second
conductive material may be changed from layer-to-layer as desired
so that on some layers the sacrificial material may be deposited
first while on other layers the structural material may be
deposited first.
[0180] In other embodiments where two conductive materials are to
be deposited, it may be possible to avoid a second patterning
operation of the dielectric material or to avoid removing,
reapplying and then patterning a second dielectric material. In
such alternative embodiments, it may be possible to initially
pattern the dielectric material to form voids that represent the
union of the locations where the first and second conductive
materials will be deposited. After which a seed layer for the first
conductive material may be applied, the first conductive material
may be applied to fill all voids, and then the deposit(s) may,
optionally, be trimmed (e.g. planarized) to a desired level. Next a
mask may be overlaid on the surface of the first conductive
material. Voids may exist in the mask at the time of mating the
masking material to the previously deposited materials.
Alternatively, the voids may be formed in the masking material
after mating has occurred. The mask may, for example, be of the
contact or adhered type. The voids in the mask preferably
correspond to locations where a second conductive material is to be
located. Etching of the first conductive material may occur to a
desired depth and even exposed seed layer material may be removed
(and potentially other associated materials as well). If the seed
layer is to be removed, it may be removed by the same process (e.g.
etchant) as is used for removing the conductive material or
alternatively it may be removed by a different process (e.g.
etchant). Next, with or without removing the masking material that
was used for etching, the second conductive material may be
deposited and if necessary prior to that deposition, a seed layer
material or seed layer stack of materials appropriate for the
second conductive material may be deposited. After deposition of
the second conductive material, the mask may be removed (if not
already removed) and planarization of the surface may occur to
remove any seed layer material or seed layer stack materials
located above the first conductive material and to bring the net
layer height to a thickness equal to that of the layer
thickness.
[0181] Techniques for forming structures using etching operations,
as set forth in the above embodiment, are more fully described in
U.S. patent application Ser. No. 10/434,519 filed on May 7, 2003 by
Dennis R. Smalley and entitled "Methods of and Apparatus for
Electrochemically Fabricating Structures Via Interlaced Layers or
Via Selective Etching and Filling of Voids". This referenced
application is incorporated herein by reference as if set forth in
full herein. This referenced application teaches, among other
things, the fabrication of multi-layer structures by depositing a
first material, selectively etching the first material (e.g. via a
mask), depositing a second material to fill in the voids created by
the etching, and then planarizing the depositions so as to bound
the layer being created and thereafter adding additional layers to
previously formed layers. The first and second depositions may be
of the blanket or selective type. The repetition of the formation
process for forming successive layers may be repeated with or
without variations (e.g. variations in patterns, numbers or
existence of or parameters associated with depositions, etchings,
and or planarization operations; the order of operations, or the
materials deposited). Other disclosed embodiments form multi-layer
structures using operations that interlace material deposited in
association with some layers with material deposited in association
with other layers. The techniques disclosed in this referenced
application may be combined with the techniques set forth
explicitly herein to derive additional alternative embodiments.
[0182] For example, in other alternative embodiments, it may be
possible to interlace material deposited in association with
different layers. For example, in some such embodiments, the
following process flow may be used: [0183] (1) A seed layer
material may be deposited to the surface of the (n-1).sup.th layer.
[0184] (2) A mask may be placed over the seed layer material and
patterned to have openings where interlacing of conductive
structural material is to occur. These opening presumably occupy
only a portion of the regions of conductive structural material on
layer n-1 but in some embodiments may occupy the entire area of the
structural material on layer n-1. [0185] (3) An etching operation
may be performed to create voids in the exposed seed layer material
and then into the conductive structural material. The thinness of
the seed layer may be used to help ensure the etched areas do not
expanded excessively in the plane of the layers. [0186] (4) The
masking material may then be removed. [0187] (5) The seed layer
material may then be removed (e.g. by chemical etching or possibly
by electrochemical etching). [0188] (6) A new masking material may
be applied to the previously formed layer and it may be patterned.
Openings in the masking material will exist in regions that are to
receive deposition of a first conductive material. If the first
conductive material is the material intended to fill the voids in
layer n-1 then the masking material will not cover the regions of
the holes but if the first conductive material is not intended to
fill the voids, the voids will be covered by the masking material.
The patterning of the masking material will be such that regions to
receive a selected one of a structural conductive material or a
sacrificial conductive material will be exposed. A seed layer will
be deposited onto the masking material and on to the surfaces
exposed by the voids in the masking material. [0189] (7) The first
of the structural or sacrificial materials may then be deposited.
[0190] (8) The layer may be planarized to a height of LT+.delta.,
or in some alternatives, such planarization may not be necessary,
e.g. where sufficient uniformity of deposit exists and where a
second masking material will be added to allow selective etching
through the seed layer over the dielectric or through the first
deposited conductive material. [0191] (8) The masking material may
be further patterned or the first deposited material may be
patterned (e.g. after application and patterning of a second
desired masking material) so as to form voids for receiving the
second of the conductive or sacrificial materials. [0192] (9) A
seed layer may be applied over the first and possibly second
masking material, over the first of the deposited conductive
materials (if not covered by second masking material and into any
voids in the present layer and any voids in the previous layer that
have become exposed by removal of selected portions of the first
masking material. [0193] (10) The second of the conductive
materials may be deposited. [0194] (11) The deposits may be
planarized to a level corresponding to the layer thickness, LT so
as to complete (at least temporarily the formation of layer n).
[0195] (12) Operations (1)-(11) may be repeated to form additional
layers as necessary to complete formation of the structure or other
operations may be used to complete formation of the structure.
[0196] In some alternatives to this embodiment, a seed layer may
not need to be applied prior to performing an etching operation
when the etching operation is not electrochemical in nature (e.g.
it is merely a chemical etching operation) or if a conductive flow
path already exists between the surface regions to be etched and a
contact location or location on the structure or substrate which
may be used for closing a circuit loop for electrochemically
etching the material.
[0197] In still further embodiments, it may be desirable to not use
a mechanical-type or machining-type operations (e.g. lapping,
polishing, machining, fly cutting, milling or the like) to trim
seed layer material from the surface of the dielectric or other
conductive material which it overlays. In some embodiments etching
operations may be used to remove the seed layer material. In some
alternative embodiments, the etching operations may be done in a
selectively manner or largely selective manner such that seed layer
material is attacked and removed while causing no more than
insignificant damage to any deposited conductive materials that are
exposed. In other alternative embodiments, the seed layer etching
process may also attack the material that was deposited above the
seed layer and/or attack other exposed conductive and/or dielectric
materials. In such embodiments, the coating thickness of the
materials attacked by the etchant may be such that the etching is
insufficient to cause the regions to fall below a desired minimum
thickness (e.g. below a level corresponding to the layer
thickness). After the etching operations have operated on the seed
layer material, sufficiently, the deposited materials may be ready
for receiving subsequent deposits and processing or alternatively a
planarization operation may be used to bring the surface of the
deposited material to a desired level. In some embodiments,
scratching or otherwise forming openings in the seed layer may be
sufficient to allow an etchant (e.g. developer or stripper) to
attack the underlying dielectric material (e.g. photoresist) which
may result in removal of the dielectric as well as removal of any
overlying seed layer material by a lift off process. Such removal
via lift off may be accompanied by ultrasonic agitation or the
like.
[0198] In additional embodiments, the etching operations set forth
above may be used to incorporate additional structural or
dielectric materials of either the conductive or dielectric type.
In some embodiments, the etching operations may be used in such a
manner that at any given time only one material is being etched
into. In other alternatives etching operations may cut into more
than one material simultaneously. In some embodiments, the depth of
etching may result in interlacing that extends to a fraction of a
layer thickness, in others the depth may be greater than one layer
thickness, while in still others a combination of depths may be
used.
[0199] In still further embodiments, the orders of applying
materials in the above described embodiments may be modified along
with making appropriate changes to the processes. For example, in
embodiments where a dielectric material is to be applied first,
followed by deposition of conductive structural material, and then
by deposition of a conductive sacrificial material, the order may
be changed such that one of the conductive materials is deposited
first, etched into, and then the dielectric material applied and
then the other of the conductive materials deposited.
[0200] In still further embodiments, additional operations may be
undertaken. For example, roughening of planarized surfaces may be
used to enhance adhesion between the masking material and the
surface and/or to enhance adhesion between a seed layer and the
surface. As another example, various cleaning or other activation
operations may be used to prepare surfaces for receiving
depositions.
[0201] The techniques disclosed explicitly herein may benefit by
combining them with the techniques disclosed in U.S. patent
application Ser. No. ______ filed concurrently herewith by Adam
Cohen et al. and entitled "Methods and Apparatus for Forming
Multi-Layer Structures Using Adhered Masks" and having Microfabrica
Docket No. P-US098-A-MF. This referenced application is
incorporated herein by reference as if set forth in full herein.
This referenced application teaches various electrochemical
fabrication methods and apparatus for producing multi-layer
structures from a plurality of layers of deposited materials where
adhered masks are used in selective patterning operations.
[0202] The techniques disclosed explicitly herein may benefit by
combining them with the techniques disclosed in U.S. patent
application Ser. No. 10/697,597 filed on Oct. 29, 2003 by Michael
S. Lockard et al. and entitled "EFAB Methods and Apparatus
Including Spray Metal or Powder Coating Processes". This referenced
application is incorporated herein by reference as if set forth in
full herein. This referenced application teaches various techniques
for forming structures via a combined electrochemical fabrication
process and a thermal spraying process or powder deposition
processes. In some embodiments, selective deposition occurs via
masking processes (e.g. a contact masking process or adhered mask
process) and thermal spraying or powder deposition is used in
blanket deposition processes to fill in voids left by the selective
deposition processes. In other embodiments, after selective
deposition of a first material, a second material is blanket
deposited to fill in the voids, the two depositions are planarized
to a common level and then a portion of the first or second
materials is removed (e.g. by etching) and a third material is
sprayed into the voids left by the etching operation. In both types
of embodiments the resulting depositions are planarized to a
desired layer thickness in preparation for adding additional
layers.
[0203] The techniques disclosed explicitly herein may benefit by
combining them with various elements of the dielectric build on
and/or incorporation techniques disclosed in the following patent
applications (1) U.S. Patent Application No. 60/534,184 filed
concurrently herewith by Adam L. Cohen et al and entitled
"Electrochemical Fabrication Methods Using Dielectric Substrates
and/or Incorporating Dielectric Materials"; (2) U.S. Patent
Application No. 60/533,932 filed concurrently herewith by Adam L.
Cohen et al. and entitled "Electrochemical Fabrication Methods
Using Dielectric Substrates and/or Incorporating Dielectric
Materials"; (3) U.S. Patent Application No. 60/534,157, which is
entitled "Electrochemical Fabrication Methods Incorporating
Dielectric Materials", filed concurrently herewith by Lockard et
al; and (4) U.S. Patent Application No. 60/533,895 filed
concurrently herewith by Lembrikov et al, and entitled
"Electrochemical Fabrication Method for Producing Multi-layer
Three-Dimensional Structures on a Porous Dielectric". These
applications are hereby incorporated herein by reference as if set
forth in full.
[0204] The techniques disclosed explicitly herein may benefit by
combining them with the techniques disclosed in U.S. patent
application Ser. No. 10/309,521, filed Dec. 3, 2002, by Brown et
al., entitled "Miniature RF and Microwave Components and Methods
for Fabricating Such Components" and published as US 2003-0222738
A1 and U.S. patent application Ser. No. 10/607,931, filed Jun. 27,
2003, by Brown et al, entitled "Miniature RF and Microwave
Components and Methods for Fabricating Such Components" provide
examples of devices that may benefit dielectric incorporation
techniques explicitly disclosed herein. These applications also
provide alternative techniques for incorporating dielectrics that
may be combined with the techniques explicitly disclosed herein to
derive additional embodiments of the invention.
[0205] Adhered Masks by Transfer Plating
[0206] As noted previously, in some embodiments of the invention,
adhered masks may be formed by transferring preformed patterns of
material. In such embodiments, plating tools having raised features
and recesses are formed and used to transfer a masking material, or
precursor thereof, in a desired pattern to a substrate or
previously formed layer. These tools may be formed in a variety of
ways such as those taught in the '630 patent for forming
electroplating articles (i.e. contact masks). These tools are used
as master patterns for transferring patterns of solidifiable
masking material to a substrate or previously formed layer. After
transfer, the precursor of the masking material is allowed to
solidify or is made to solidify. In some embodiments, multiple
transfers of material may be made to enhance the thickness of
depositions or to improve the electrochemical or chemical blocking
ability of the coatings once solidified. When making multiple
transfers, the same material may be transferred each time or
different materials may be transferred. When making multiple
transfers the previous transferred material may be allowed to, or
made to, partially or completely solidify prior to a subsequent
transfer. Alternatively, the subsequent transfer may be made with
the previously transferred material remaining in a fluid state such
that intermixing of multiple materials may occur. Such intermixing
may, for example, be useful in working with masking materials that
are based on two-part chemical systems (e.g. some epoxy systems).
In some embodiments, the transferred material(s) may function as
build material(s) in combination with other deposited material(s)
while in other embodiments they may solely function as mask
materials. When functioning as build materials they may be used as
structural materials or as sacrificial materials.
[0207] Transferred materials will preferably offer adequate
adhesion to the substrate and previously deposited materials such
that transfer can readily occur and such that after solidification
masks of adequate structural integrity are obtained. They will
preferably be adequately compatible with electrodeposition and/or
etching baths as well as plating and/or etching operations that
will be employed during the time that the masking material is
present such that entire layer thicknesses may be deposited and/or
sufficient depths etched without need for replacing the mask. In
some embodiments the replacement of masks may be acceptable. The
materials are preferably compatible with optimal cleaning solutions
and processes as well as with activation solutions and processes,
and the other build environments and processes to which they may be
subjected. In embodiments where deposition of adhesion layer
materials and seed layer materials will be applied to the masking
material or the masking material applied thereon, the masking
material(s) are to be compatible with such materials. In some
embodiments, preferred masking materials may be dielectrics while
in other embodiments masking materials may be conductive materials.
In some embodiments structural materials and/or sacrificial
materials may need to be separable from the masking materials while
in other embodiments such ability to separate may be unnecessary.
Separation may occur by a variety of operations (e.g. heating to
melt, chemical dissolution, electrochemical separation, breakdown
by exposure to radiation, burning out, and the like.
[0208] Precursor masking materials once transferred may become
solidified masking materials by a variety of processes, such as
curing (e.g. polymerization by exposure to radiation, e.g. UV, or
heat), phase change by lowing or raising temperature, and/or
solvent removal (e.g. evaporation), or the like. In still other
embodiments, colorants or other additives may be included in the
masking materials for a variety of reasons.
[0209] A seventh embodiment uses transferred masking material that
is a dielectric (e.g. a wax, a photopolymer, a thermoset polymer,
or the like, and uses first and second conductive materials as
building materials. Herein the term "ink" will be periodically used
in a generic fashion to refer to a precursor or unsolidified
masking material. The first operation in the process is to transfer
a liquid, paste-like, or gelatin-like masking precursor material to
a surface of the substrate (or previously formed layer). The
transfer occurs in a patterned manner using a patterned transfer
tool having raised areas (e.g. plateaus or lines) and recessed
areas (e.g. valleys or trenches). The patterned tool in some
variations of this seventh embodiment may take a form similar to
that of the electroplating articles described in the '630 patent
but in the present process such "articles" or tools are not used
for plating but instead are used as patterns for transferring
selective patterns of the precursor masking material. In this
embodiment, the plateaus of the tools are contacted to a volume of
the precursor material whereby the plateaus pick up the precursor
material while the valleys do not. The tool having the precursor is
then translated and/or rotated to a desired transfer position
relative to the substrate whereby the patterned precursor is
contacted to the substrate and transferred to the substrate in a
pattern dictated by the tool patterning. In the present embodiment
the substrate is assumed to be conductive and though in other
embodiments it may be a dielectric and a seed layer may be used to
make it platable.
[0210] In a second operation the transferred precursor masking
material is allowed to, or forced to solidify, and to thereby
become the masking material. Depending on the precursor selected,
transformation from the liquid, gel-like, or paste-like state may
occur by allowing or forcing solvent evaporation, allowing or
forcing a chemical reaction between constituents of the precursor
or between the precursor constituents and one or more additional
materials applied to the precursor. Depending on the precursor
being used, the forcing mechanism may include one or more of time;
heat (e.g. via elevated temperature); reduced partial pressure
(e.g. application of a vacuum); increased pressure; exposure to
radiation such as UVR, IRR, visible light, X-rays, electron beams,
and the like; increased pressure; and/or removal of inhibition
agents (e.g. the removal of oxygen from a free radical curing
system). In variations of this embodiment, this second operation
may occur after separation of the transfer tool from the precursor
material or it may occur while the transfer tool remains in contact
with the precursor/masking material.
[0211] If necessary, a third operation may be performed to remove
small quantities of masking material from undesired locations.
Depending on how transfer has occurred, small quantities of masking
material or precursor material may be left at undesired locations
on the substrate or previously formed layer. This operation may be
performed by an etching operation that is tailored to the
particular precursor, masking material, substrate material, and
build materials that may be present. The etching operation may be
performed for a controlled amount of time with an etchant
concentration or quantity and at a temperature that will remove the
unwanted precursor or masking material without significantly
damaging the substrate, previous layer, or masking material that is
properly located. This etching operation may also remove any
adhesive or chemical that may have been used in the process of
achieving a successful transfer. In some alternative embodiments,
the original configuration of the transferred material may be
modified from a desired configuration so as to compensate for any
dimensional changes that occur as a result of this type of removal
operation.
[0212] The fourth operation of this seventh embodiment involves the
deposition of a first building material. In this embodiment the
building material is conductive and is deposited via
electroplating. In alternative embodiments, however, other types of
materials may be used (e.g. dielectrics) and the deposition may be
performed in a different manner, for example by electroless
plating, electrophoretic deposition, spraying, sputtering,
spreading, or like. The deposition in one sense may be considered a
bulk deposition but in another sense it may be considered a
selective deposition as a result of the dielectric mask material
acting as a barrier to the electroplating of the first building
material.
[0213] The fifth operation of this seventh embodiment removes the
masking material from the substrate, or previously formed layer,
and from the edges of the first building material. This removal may
occur in a variety of ways depending on the masking material used,
the first material, the material of the substrate, and/or how the
materials of the previous layer will be exposed by the removal
process. The removal may occur by, for example, dissolving the
masking material in a solvent, reducing adhesion between the mask
material, the substrate and the first building material, burning
out the masking material, using high temperature or pressure steam,
mechanical abrasion, or the like.
[0214] If needed or desired, a sixth operation may involve another
removal operation. This removal operation is intended to remove any
small or thin unwanted regions of the first building material that
were deposited. This operation may take the form of a flash etching
operation. Such small or thin regions may result from small holes
in the masking material or from plating into thin voids that may
exist between portions of the masking material and the
substrate.
[0215] The seventh operation of this seventh embodiment deposits a
second building material, which is conductive. In this embodiment
the deposition occurs by electroplating. In alternative
embodiments, other deposition choices and material types are
possible.
[0216] The eighth operation of this embodiment planarizes the
deposited material down to a level that bounds the present layer.
In this embodiment, the planarization operation is by lapping but
in other embodiments the planarization operation may take other
forms such as, for example, chemical mechanical polishing (CMP)
milling, fly cutting (diamond), or other machining operations. This
operation completes formation of the layer.
[0217] Next the first through eighth operations are repeated one or
more time to form a structure from a plurality of adhered layers
and thereafter one of the two materials may be separated from the
other so as to release a structure of desired material and
configuration.
[0218] In some alternative embodiments, structures may be formed
using operations 1-8, as described above, to form some layers while
other operations, or other orders of operations, may be used to
form other layers.
[0219] In some alternatives to the seventh embodiment the precursor
material may be cured or solidified prior to contacting it to the
substrate in a transfer process. In still other alternatives, the
surface of the masking material and/or the substrate (or previously
formed layer) may be treated to enhance the affinity or
adhesiveness between the masking material and the substrate (or
previously formed layer). Such treatment may, for example, roughen
the surface of the substrate, it may enhance the chemical
reactivity of one of the surfaces relative to the material of the
other surface, it may apply an adhesive (e.g. a contact adhesive),
or the like to one or both surfaces. If additives are placed on the
surface of the substrate (or previous layer) in a blanket manner, a
cleaning or etching operation may be necessary to ready the surface
for acceptance of a material to be deposited.
[0220] In some alternative embodiments, the precursor masking
material may be spread over the plateaus and into the valleys and
then wiped from the plateaus, where after the tool may be contacted
to the substrate and the precursor material transferred from the
valley to the substrate. In these embodiments the surface of the
tool may be made to have less affinity for the precursor material
than the precursor material has for the substrate (and previously
formed layers). Alternatively, the precursor material may be cured
prior to separating the tool and the substrate whereby the masking
material (cured precursor material) adheres better to the substrate
than to the tool thus enhancing the probability of a successful
transfer. In some embodiments, the face of the tool or the support
for the tool may be flexible which may be useful in aiding the
transfer process.
[0221] In some alternative embodiments, where mask thickness is
less than a desired layer thickness, and where multiple stamping
operations will be used to increase the mask thickness, the
multiple stamping operations may be performed with different sized
masks, or with a single mask stamped multiple times at slightly
offset positions. Such variations in sizing or offsetting in
position may provide a taper or finer stair step to the sidewalls
of the mask which in turn may be of use in helping to reduce
layer-to-layer discontinuities in the deposited materials. Such
inter-layer discontinuity reduction is discussed further in U.S.
patent application Ser. No. 10/830,262, entitled "Methods of
Reducing Interlayer Discontinuities Electrochemically Fabricated
Three Dimensional Structures", filed Apr. 21, 2004, by Cohen et
al.
[0222] In an some alternative embodiments, instead of using a
transfer tool having a contour surface (i.e. plateaus and valleys),
a substantially planar mask or cylindrical mask may be used wherein
the surface of the mask is treated, or the mask may be composed of
different materials, such that different regions have different
affinities or aversions to the precursor material. Such a surface
may be capable of holding a precursor at selected locations for
transfer while other portions of the surface cannot.
[0223] FIGS. 16(a)-16(q) schematically depict side views at various
stages of an implementation of the seventh embodiment as applied to
the formation of a multi-layer structure.
[0224] FIG. 16(a) depicts an ink (precursor masking material) 902
located on a support 904. A patterned transfer tool 906 includes a
support 908 and a patterned portion 910. The patterned portion 910
is moved in the direction of arrow 912, relative to the support and
the ink, until contact between the patterned portion 910 and the
ink 902 is made.
[0225] FIG. 16(b) depicts the state of the process where contact
between the patterned portion 910 and the ink has been made. After
contact, the transfer tool 906 is moved, relative to the support
904, in the direction of arrow 914.
[0226] FIG. 16(c) depicts the state of the process after the
separating has occurred. As shown in FIG. 16(c), the portion of the
ink 902 that contacted the patterned portion 910 of the tool 906
preferentially adhered, at least temporarily, to the patterned
portion 910. After completion of movement in the direction of arrow
914, the tool 906 carrying ink 902 is moved in the direction of
arrow 916, relative to a substrate 922, in order to position the
tool 906 over the substrate 922. The substrate 922 is the substrate
onto which the multi-layer structure will be formed.
[0227] FIG. 16(d) depicts the state of the process after the
movement along the direction of arrow 916 is completed and movement
in direction of arrow 918 begins.
[0228] FIG. 16(e) depicts the state of the process after movement
in direction 918 is completed and the ink is made to contact the
substrate 922. After making contact, the tool 906 moves in the
direction of arrow 920, relative to the substrate 922.
[0229] FIG. 16(f) depicts the state of the process after movement
in direction 920 is completed. As a result of the contact between
ink 902 and substrate 922 and then the separating of the tool and
the substrate, the ink preferentially remains on or adheres to
substrate 922 and becomes separated from tool 906. FIG. 16(f) also
shows that ink 902 has been converted to masking material 932 due
to a transformation (e.g. polymerization, freezing, or the like).
The transformation may have occurred prior to the separation of
transfer element 906 from support 922 or may have occurred
thereafter.
[0230] FIG. 16(g) schematically depicts the substrate 922 located
within a plating tank 924. The plating tank includes an anode 934
which includes a desired material 942 that is to be deposited onto
the substrate 922. The plating tank also includes a plating bath
926 that is appropriate for transferring material from the anode to
the substrate which is biased as a cathode by power supply 928.
When appropriately biased and current flow initiated, material 942
will be electroplated from an anode 934 through plating bath 926
onto substrate 922 via openings 936 through masking material
932.
[0231] FIG. 16(h) depicts the state of the process after deposition
of a first building material 942 onto the substrate 922 occurs.
[0232] FIG. 16(i) depicts the state of the process after the
substrate 922 and partially formed first layer are removed from
plating tank 924.
[0233] FIG. 16(j) depicts the state of the process after separation
of the masking material 932 from the substrate 922 which leaves
behind a patterned deposit of material 942.
[0234] FIG. 16(k) depicts the state of the process after loading
the substrate and partially patterned first layer into plating
station 962. The plating station 962 includes an anode 964 composed
of a second material to be plated and contains a plating solution
966 which will be used to transfer ions of the second material from
anode 964 to substrate 922 and to regions on the first deposited
material 942. (assuming they are not shielded in same manner).
[0235] FIG. 16(l) depicts the state of the process after deposition
of the second building material 968 onto the substrate and the
patterned deposit of material 942 while FIG. 16(m) depicts the
state of the process after removal of the substrate and deposited
materials from plating tank 962.
[0236] FIG. 16(n) depicts the state of the process after the first
layer L1 is completed by planarizing the deposited materials down
to a level that bounds the first layer.
[0237] FIG. 16(o) depicts the state of the process after deposition
of four more layers completes the formation of the layers of sample
structure 972 or 972'.
[0238] FIGS. 16(p) and 16(q) depict alternative states of the
process after one of the materials 942 or 968 has been removed and
the structure 972 or 972' of desired material and configuration is
released.
[0239] FIGS. 17(a)-17(d) schematically depict side views of various
states of an alternative process that involves rolling a
cylindrical support carrying a pattern of ink across a substrate
for transferring the ink to the surface of a substrate in
preparation for depositing layers of a structure on the
substrate.
[0240] FIG. 17(a) depicts a cylindrical support 1002 being brought
into contact with a backing sheet 1006 for an ink 1004 which it
holds in position. The cylindrical support is loaded with the ink
by rolling across the backing material. The pattern of ink may have
been deposited to the backing material by inkjet dispensing,
selective extrusion, photoresist (e.g. dry film) exposure and
development, or by any other appropriate manner. In an alternative
embodiment, the patterning of the ink with or without a backing
material may have occurred directly onto the cylindrical
support.
[0241] FIG. 17(b) depicts the state of the process after the
masking material and backing sheet 1006 are loaded onto support
1002 and support 1002 is placed in an initial position above an
edge of substrate 1012 in preparation for rolling the ink onto the
substrate.
[0242] FIG. 17(c) depicts the state of the process after
cylindrical support 1002 has rotated about half way across the
surface of the substrate in the process of depositing, or
transferring, ink to the substrate. FIG. 17(c) illustrates that a
portion of masking material 1004 has been deposited. Before,
during, or after transfer, ink 1004 may undergo treatments that
cause it so become masking material 1014, and if transformation
occurs before transfer material 1014 or a surface of substrate 1012
may be treated to enhance adhesion of the material 1014 to the
substrate surface. FIG. 17(c) depicts a portions of ink 1004 has
been transfer and become material 1014 while additional ink 1004
has not yet been transferred.
[0243] FIG. 17(d) depicts the state of the process after rotation
of support 1002 across the surface of the substrate has been
completed and all of ink 1004 has been transferred to the substrate
1012 and has become selectively patterned masking material 1014. At
this point, the masked substrate is ready for receiving a selective
deposition of a first building material as described herein
previously with regard to the first embodiment and its various
alternatives.
[0244] FIGS. 18(a)-18(e) schematically depict an alternative
embodiment for transferring a patterned ink from a cylindrical
support 302 to a substrate 312. In this embodiment a backing
material 306 does not remain adhered to the support when the ink
material 304 transfers to the substrate but instead the backing
material is also transferred along with the ink.
[0245] FIG. 18(a) depicts a beginning point of the process where a
cylindrical roller 1102 has on its surface a backing material 1106
on which a patterned ink 1104 is located. The ink may be in a
paste-like state or semisolid or even solid state. The cylindrical
support is positioned relative to the substrate 1112 such that
transfer of ink can begin.
[0246] FIG. 18(b) depicts the state of the process after a portion
of the ink has been transferred from the support to the substrate
along with a portion of the backing material by rolling the support
across the surface of the substrate.
[0247] FIG. 18(c) depicts the state of the process after the
rotation of cylindrical support 1102 relative to substrate 1112 has
resulted in the complete deposit of the patterned ink 1104 and the
backing material 1106 onto the substrate.
[0248] FIG. 18(d) depicts the state of the process after the ink
1104 has been transformed into masking material 1114. In this
example, the transformation occurs prior to separating the backing
material 1106 from the ink/masking material. In other embodiments
transformation may occur before transfer and thereafter adhesion
may be made to occur.
[0249] FIG. 18(e) depicts the state of the process after the
backing material 1106 has been removed from the masking material
1114 such that the patterned substrate is ready to receive
deposition of a first building material as described herein
previously with regard to the first embodiment and its various
alternatives.
[0250] An eighth embodiment starts with a metal substrate on to
which an ink is transfer plated (i.e. using a transfer tool) to
form a pattern of the conductive material (i.e. plateaus) through
which voids or valleys exist. In this embodiment, as well as the
other embodiments presented herein, the transfer process and
deposition processes to follow may be performed in any orientation
(upward, downward, sideways or any combination). The transfer
operations may be performed as described in association with the
seventh embodiment or one of its alternatives, or in some other
manner that will be apparent to those of skill in the art upon
reviewing the teachings herein.
[0251] As in the seventh embodiment, if necessary, the transferred
material may be given time to transform (e.g. to dry) or
alternatively it may be made to solidify (e.g. by application of
heat or radiation, or the like). As in the seventh embodiment, it
may be made to flow by application of heat, or by other techniques,
for example, to help fill in any micro-voids in the ink that may
carry over to the masking material. In some embodiments, drying or
solidification may be allowed to occur several times before a
completely coated area is obtained. If the deposition height is not
at least as great as one layer thickness (LT), transfer and
potentially transformation may be repeated multiple times to build
up the thickness. In this repetition process the transformation
operations may be performed after every transfer, not performed at
all, performed after a selected number of transfers, or performed
only after the last transfer.
[0252] Once the mask height is at least as great as the layer
thickness and preferably somewhat greater, a blanket
electrodeposition of a second material is performed. The blanket
deposition may be performed as a single operation or in a plurality
of operations (e.g. depositions separated by intermediate short
etching operations) to fill the valleys formed by the masking
material on the substrate. The filling eventually reaches a depth
at least as great as the layer thickness and potentially somewhat
greater. The plateaus of masking material may also receive a
deposition of the second material as the plateaus are formed of
conductive material.
[0253] Next a planarization operation is used to yield a first
layer of the structure which has an upper surface which bounds the
first layer. The first layer consists of the masking material (i.e.
a first material) and the second material, each located on
different portions of the substrate.
[0254] Next, operations of mask formation (e.g. transferring,
transforming, repeating, and the like), electrodeposition, and
planarization are repeated a plurality of times to form a plurality
of adhered layers.
[0255] After layer formation is complete, one of materials may be
removed to yield a released structure of desired material and
configuration.
[0256] In an eighth embodiment, a multi-layer three-dimensional
structure is formed from a plurality of adhered layers where one
conductive material is electrodeposited, where the transferred
ink/masking material is a dielectric material, and where a second
building material is deposited which is also a dielectric. This
embodiment includes seven primary operations that are repeated a
plurality of times in forming a multi-layer structure.
[0257] The primary operations of this eighth embodiment include (1)
depositing a seed layer, if necessary, and an adhesion layer, if
necessary, onto a substrate which may include previously deposited
layers of material and which may be a dielectric, (2) formation of
a mask by transfer plating ink and then allowing it to solidify or
cure, (3) depositing a first conductive material, e.g. via
electrodeposition, into voids in mask, (4) removing the mask, (5)
removing the exposed adhesion/seed layer that is located between
the regions where the first conductive material was deposited, (6)
depositing a second material which is a dielectric by, for example,
electrophoretic deposition, spreading, spraying, sputtering, and
the like, and (7) planarizing the deposited materials to form a
first layer of the structure. Next the process repeats operations
(1)-(7) a plurality of times to complete layer formation and
thereby build up a multilayer structure. After all layers are
formed, and if desired, one of the first or second materials may be
separated from the other to release a structure of desired material
and configuration. Alternatively the combination of a conductive
and dielectric structure may be used without a release.
[0258] Direct Fabrication of Masks
[0259] In the some embodiments of the invention, masks may be
generated directly from computer data. In some of these embodiments
computer controlled selective deposition devices are used to
deposit material to selective regions in the form of droplets (e.g.
via one or more ink jet heads or the like) or in the form of one or
more modulated streams of material (e.g. extrusion devices or the
like). By use of these devices, computer data may be used to
directly form masks into which one or more other materials may be
deposited. In some embodiments, the dispensed material(s) may
function as build material(s) along with the other deposited
material(s). Such use of these methods allow desired structure
formation to occur without the need for tooling (e.g. photomasks or
the like) to form masking structures.
[0260] Ink jet devices useful in some embodiments may take on a
variety of forms. Devices may be, for example, of the
piezo-electric driven type or of the thermally driven type. Devices
(print heads) may have a single orifice, a multi-orifice head, or
multiple multi-orifice heads. Positioning of the device relative to
the substrate or previously formed layers may occur via movement of
the print head, or movement of the substrate or a combination of
the two. Data that drives the relative positioning of the print
head and/or the dispensing of droplets may be cross-sectional data
supplied directly or it may be data derived from a
three-dimensional structure and associated build volume (i.e.
combination of the desired three-dimensional structured and
surrounding region that is to be occupied by other build material).
The data may be modified to enhance the accuracy of the structure
being formed. For example, it may be modified to compensate for the
width of the droplets that are being dispensed or to compensate for
size differences resulting from temperature differentials at
dispensing temperatures, plating temperatures, and use
temperatures, and the like. During the formation of a given mask,
the mask may be formed from a single level of drops or from
overlaid and even offset drops. In boundary regions, if multiple
overlaid drops are required, the drops may be dispensed to
positions which are offset to the midpoints of previously dispensed
droplet locations to smooth any discontinuities associated with the
quantization associated with dispensing locations or droplet size.
Some ink jet devices may offer grey scale printing or droplet size
modulation to improve filling or boundary region smoothness.
[0261] In some embodiments, where mask thickness is less than
desired layer thickness, and where multiple overlaid dispensings of
material are required to increase the mask thickness, the edge
locations of successive levels of dispensing maybe slightly offset
from positions associated with previous dispensings in order to
give a taper or finer stairstep (i.e. finer than the resolution
associated with the layer thickness) to the sidewalls of the mask
which may be of use in helping to reduce layer-to-layer
discontinuities in the deposited material. Such discontinuity
reduction is discussed further in U.S. Provisional patent
application Ser. No. 10/830,262, entitled "Methods of Reducing
Interlayer Discontinuities Electrochemically Fabricated Three
Dimensional Structures", filed Apr. 21, 2004, by Cohen et al.
[0262] In some embodiments, as small gaps in the dispensed masks
may exist, and where masking material is removed after the
selective deposition of a first material, a flash etch (i.e. an
etch that removes only a small amount of material) may be employed
to clean up any small regions of the first material that are
inadvertently deposited prior to proceeding with deposition of
second material, or the like.
[0263] A ninth embodiment forms a multi-layer three-dimensional
structure from a plurality of adhered layers where a single
material is electrodeposited and where the dispensed masking
material is a conductive material and forms a building
material.
[0264] The ninth embodiment starts with a metal substrate on to
which ink jets, or the like, are used to selectively dispense a
layer of conductive material (e.g. solder or a cerro alloy) onto
the substrate to form a pattern of the conductive material (i.e.
plateaus) through which voids or valleys of non-deposited regions
exist. The deposition process may be performed in any orientation
(upward, downward, sideways, or in any combination).
[0265] If necessary, the dispensed material may be given time to
transform. Transformation may occur, for example by application of
heat (e.g. via elevated temperature; reduced partial pressure (e.g.
application of a vacuum); increased pressure; exposure to radiation
such as UVR, IRR, visible light, X-rays, electron beams, and the
like; increased pressure; and/or removal of inhibition agents (e.g.
the removal of oxygen from a free radical curing system). It may be
made to flow by application of heat, or by other techniques to fill
in any micro voids in the deposition region that may exist. In some
embodiments, drying or solidification may be allowed to occur
several times before a completely coated area is obtained. If the
deposition height is not at least as great as one layer thickness
(LT) the dispensing and transformations may be repeated multiple
times to build up the thickness. In this repetition process the
transformation operations may not be performed, performed after a
selected number of depositions, performed only after the last
deposit, or they may be performed after every deposition.
[0266] Once the deposition height is at least as great as LT and
preferably somewhat greater, a blanket electrodeposition is
performed. The blanket deposition fills the valleys to a depth at
least as great as LT (preferably somewhat greater or if
significantly greater if necessary to get reasonable boundary
profiles). The plateaus may also receive the deposition.
[0267] Next a planarization operation is used to yield a first
layer of the structure that is trimmed to a height that bounds the
first layer. The first layer consists of the ink jetted material
and the electrodeposited material, each located on different
portions of the substrate.
[0268] Next, the operations for mask formation (e.g. dispensing,
transforming, repeating, and the like), electrodeposition, and
planarization are repeated a plurality of times to form a plurality
of adhered layers each having a configuration dictated by the data
associated with each layer.
[0269] After layer formation is complete, one of deposited
materials may be removed to yield a released structure of desired
material and configuration.
[0270] Various alternatives to the ninth embodiment exist. Instead
of using only two materials, multiple structural materials may be
used (materials that become part of the final structure) and or
multiple sacrificial materials may be used. The blanket
electrodeposition operations may be replaced by a selective
deposition operation or multiple selective deposition
operations.
[0271] It will be understood by those of skill in the art that
additional operations may be used in variations of the first
embodiment. These additional operations may, e.g. perform cleaning
functions between the primary operations discussed above, they may
perform activation functions, monitoring functions, and the
like.
[0272] FIGS. 19(a)-19(i) provide schematic depictions of side views
of various stages of a process for forming a multi-layer structure,
using an ink jet deposited mask, as applied to a particular three
layer structure.
[0273] FIG. 19(a) depicts a substrate 1202 that has been
provided.
[0274] FIG. 19(b) depicts an ink jet 1204 dispensing droplets 1206'
and 1206'' onto the substrate. As indicated in the Figure, a first
dispensing location 1208 has received deposits while a number of
additional locations 1210 that are to receive masking material have
not yet received deposits.
[0275] FIG. 19(c) depicts the state of the process after all
locations 1208 and 1210 have received masking material 1212.
[0276] FIG. 19(d) depicts the state of the process after masking
material 1212 has been transformed into solidified material
1214.
[0277] FIG. 19(e) depicts the state of the process after an
additional deposition of masking material and transformation of
that masking material causes an increase in mask height 1216 to a
desired level.
[0278] FIG. 19(f) depicts the state of the process after a material
1218 has been electrodeposited into the spaces between transformed
masking material 1214 and above that transformed material as well.
The height of deposition of material 1218 is such that the minimum
deposited height meets or exceeds a layer thickness LT.
[0279] FIG. 19(g) depicts the state of the process after
planarization of the first deposited layer of material to a level
having a height LT which bounds the first layer.
[0280] FIG. 19(h) depicts the state of the process after repeating
the mask forming, the electrodepositing, and planarization
operations two additional times such that a total of three layers
(L1, L2, and L3) are formed.
[0281] FIG. 19(i) depicts the state of the process after the
masking material has been removed from the electrodeposited
material.
[0282] In some alternative embodiments the electro deposited
material may have been separated from the masking material whereby
the masking material would form the desired structure. This is
illustrated in FIG. 19(j). FIG. 19(j) depicts the state of the
process after conductive material has been removed to yield a
released structure of masking material.
[0283] A tenth embodiment forms a multi-layer three-dimensional
structure from a plurality of adhered layers where two materials
are electrodeposited (both are conductive) and where the dispensed
masking material is a dielectric material. This embodiment include
five steps that are repeated a plurality of times in forming a
multi-layer structure.
[0284] The first operation of the tenth embodiment forms a
dielectric mask on a substrate by selectively dispensing droplets
of a curable material using an ink jet print head or a modulated
stream via an extrusion device.
[0285] The second operation includes depositing a first conductive
material via electrodeposition, or in some other manner, into voids
in the mask.
[0286] The third operation removes the mask.
[0287] The fourth operation blanket deposits a second conductive
material.
[0288] The fifth operation planarizes the deposited materials such
that the height of the first deposited layer is trimmed to bound
the level of the first layer.
[0289] Next, the first through fifth operations are repeated one or
more times to form a multi-layer structure and finally after layer
formation is complete, one of the two conductive materials (the
sacrificial material) may be separated from the other conductive
material (structural material) to produce the released structure of
desired configuration.
[0290] In an eleventh embodiment a multi-layer three-dimensional
structure is formed from a plurality of adhered layers where one
conductive material is electrodeposited, where the dispensed
masking material is a dielectric material, and where a second
building material is deposited which is also a dielectric. This
embodiment includes seven steps that are repeated a plurality of
times in forming a multi-layer structure.
[0291] The primary operations of this third embodiment include (1)
depositing a seed layer, if necessary, and an adhesion layer, if
necessary, onto a substrate (i.e. a previously formed layer if
present layer is not the first layer) which may be a dielectric,
(2) formation of a mask by dispensing a dielectric masking material
via ink jet or the like, (3) depositing a first conductive
material, e.g. via electrodeposition, into voids in mask, (4)
removing the mask, (5) removing the exposed adhesion/seed layer
that is exposed between regions of the first conductive material,
(6) depositing a second material which is a dielectric by, for
example, electrophoretic deposition, spreading spraying,
sputtering, and the like, and (7) planarizing the deposited
materials to form a first layer of the structure. Next the process
repeats operations (1)-(7) a plurality of times to build up a
multilayer structure. After all layers are formed, and if desired,
one of the first or second materials is separated from the other of
the materials to release a structure of desired configuration.
[0292] In a twelfth embodiment a multi-layer three-dimensional
structure is formed from a plurality of adhered layers where one
conductive material is electrodeposited and where the dispensed
masking material is a dielectric material which is used as one of
the building materials. This embodiment includes four steps that
are repeated a plurality of times in forming a multi-layer
structure.
[0293] The primary operations of this fourth embodiment include (1)
forming a mask on the substrate (i.e. a previously formed layer if
the present layer is not the first layer) by selectively dispensing
a masking material from a ink jet device or by transfer plating or
the like to a height greater than or equal to the layer thickness
of the present layer, (2) depositing a seed layer into the voids in
the mask as well as onto the exposed upper surface of the masking
material, (3) depositing a conductive first material to a height
equal to or greater than the layer thickness of the present layer
(e.g. via an electrodeposition operations) into the voids in the
masking material and potentially above the masking material as a
result of the seed layer, and (4) planarizing the deposited
materials to the height of the present layer, i.e. to bound the
present layer, which trims off any excess thickness of the first
material and any excess thickness of the mask material as well as
the adhesion/seed layer that located above the masking material.
Next the process repeats operations (1)-(4) one or more times to
form a multi-layer structure that includes two materials per layer
one of which is the mask material. The operations result in seed
layer material only being located on some portions of the boundary
of the conductive first material without any need to use anything
other than planarization operation to remove the adhesion/seed
layer material. Finally, after layer formation is complete, if
desired, one of the materials may be removed to release a structure
having the desired configuration or the structure of combined
materials may be considered to be the final structure.
[0294] FIGS. 20(a)-20(g) provide schematic side views of various
stages of the process of the twelfth embodiment as applied to the
formation of a sample three-dimensional structure.
[0295] FIG. 20(a) depicts a substrate 1322 that is provided on
which successive layers of the structure will be formed.
[0296] FIG. 20(b) depicts a mask structure 1324 adhered to
substrate 1322. The mask structure was formed by ink jetting or
extruding a material in a desired pattern or by transfer plating
and then transforming that material into a solid.
[0297] FIG. 20(c) depicts the state of the process after a seed
layer 1326 is formed above mask material 1324 and substrate
1322.
[0298] FIG. 20(d) depicts the state of the process after deposition
of a first conductive material 1328, while FIG. 20(e) depicts the
state of the process after planarization of the deposited materials
down to a layer thickness LT of the first layer L1.
[0299] FIG. 20(f) depicts the state of the process after formation
of two additional layers L2 and L3, where each layer includes
masking material 1324, conductive material 1328, and seed layer
material 1326. The structure of FIG. 20(f) may be the final
structure as it will be used.
[0300] FIG. 20(g) depicts the state of the process after removal of
the masking material which may be considered to be a sacrificial
material. As an alternative, FIG. 20(h) depicts the state of the
process after removal of the conductive material which may be
considered a sacrificial material.
[0301] The patent applications and patents set forth below are
hereby incorporated by reference herein as if set forth in full.
The teachings in these incorporated applications can be combined
with the teachings of the instant application in many ways: For
example, enhanced methods of producing structures may be derived
from some combinations of teachings, enhanced structures may be
obtainable, enhanced apparatus may be derived, and the like.
TABLE-US-00001 US Pat App No, Filing Date US App Pub No, Pub Date
Inventor, Title 09/493,496 - Jan. 28, 2000 Cohen, "Method For
Electrochemical Fabrication" 10/677,556 - Oct. 1, 2003 Cohen,
"Monolithic Structures Including Alignment and/or Retention
Fixtures for Accepting Components" 10/830,262 - Apr. 21, 2004
Cohen, "Methods of Reducing Interlayer Discontinuities in
Electrochemically Fabricated Three- Dimensional Structures"
10/271,574 - Oct. 15, 2002 Cohen, "Methods of and Apparatus for
Making High 2003-0127336A - Jul. 10, 2003 Aspect Ratio
Microelectromechanical Structures" 10/697,597 - Dec. 20, 2002
Lockard, "EFAB Methods and Apparatus Including Spray Metal or
Powder Coating Processes" 10/677,498 - Oct. 1, 2003 Cohen,
"Multi-cell Masks and Methods and Apparatus for Using Such Masks To
Form Three-Dimensional Structures" 10/724,513 - Nov. 26, 2003
Cohen, "Non-Conformable Masks and Methods and Apparatus for Forming
Three-Dimensional Structures" 10/607,931- Jun. 27, 2003 Brown,
"Miniature RF and Microwave Components and Methods for Fabricating
Such Components" 10/841,100 - May 7, 2004 Cohen, "Electrochemical
Fabrication Methods (Docket P-US093-A-MF) Including Use of Surface
Treatments to Reduce Overplating and/or Planarization During
Formation of Multi-layer Three-Dimensional Structures" 10/387,958 -
Mar. 13, 2003 Cohen, "Electrochemical Fabrication Method and
2003-022168A - Dec. 4, 2003 Application for Producing
Three-Dimensional Structures Having Improved Surface Finish"
10/434,494 - May 7, 2003 Zhang, "Methods and Apparatus for
Monitoring 2004-0000489A - Jan. 1, 2004 Deposition Quality During
Conformable Contact Mask Plating Operations" 10/434,289 - May 7,
2003 Zhang, "Conformable Contact Masking Methods and 20040065555A -
Apr. 8, 2004 Apparatus Utilizing In Situ Cathodic Activation of a
Substrate" 10/434,294 - May 7, 2003 Zhang, "Electrochemical
Fabrication Methods With 2004-0065550A - Apr. 8, 2004 Enhanced Post
Deposition Processing Enhanced Post Deposition Processing"
10/434,295 - May 7, 2003 Cohen, "Method of and Apparatus for
Forming Three- 2004-0004001A - Jan. 8, 2004 Dimensional Structures
Integral With Semiconductor Based Circuitry" 10/434,315 - May 7,
2003 Bang, "Methods of and Apparatus for Molding 2003-0234179A -
Dec. 25, 2003 Structures Using Sacrificial Metal Patterns"
10/434,103 - May 7, 2004 Cohen, "Electrochemically Fabricated
Hermetically 2004-0020782A - Feb. 5, 2004 Sealed Microstructures
and Methods of and Apparatus for Producing Such Structures"
10/841,006 - May 7, 2004 Thompson, "Electrochemically Fabricated
Structures Having Dielectric or Active Bases and Methods of and
Apparatus for Producing Such Structures" 10/434,519 - May 7, 2003
Smalley, "Methods of and Apparatus for 2004-0007470A - Jan. 15,
2004 Electrochemically Fabricating Structures Via Interlaced Layers
or Via Selective Etching and Filling of Voids" 10/724,515 - Nov.
26, 2003 Cohen, "Method for Electrochemically Forming Structures
Including Non-Parallel Mating of Contact Masks and Substrates"
10/841,347 - May 7, 2004 Cohen, "Multi-step Release Method for
Electrochemically Fabricated Structures" 60/533,947 - Dec. 31, 2003
Kumar, "Probe Arrays and Method for Making"
[0302] 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 use selective deposition processes or blanket
deposition processes on some layers that are not electrodeposition
processes. Some embodiments, for example, may use nickel, gold,
copper, tin, silver, zinc, solder as structural materials while
other embodiments may use different materials. Some embodiments,
for example, may use copper, tin, zinc, solder or other materials
as sacrificial materials. Some embodiments may remove a sacrificial
material while other embodiments may not. Some embodiments may use
photoresist, polyimide, glass, ceramics, other polymers, and the
like as dielectric structural materials. Some embodiments may use,
for example, Futurrex Protective Barrier Coating 3-6000, which has
a dielectric constant of 2.5 and is curable at 150.degree. C. Some
embodiments may use Shipley Intervia.TM. Photodielectric Materials
(such as 8010 and 8021 which are negative photoresists) as
structural dielectrics. These materials are available from Shipley
Far East Ltd. of Tokyo Japan. Some embodiments, for example may use
Shipley BPR 100 Photoresist (which is a negative photoresist)
available from Shipley Company of Marlborough, Mass.
[0303] In some embodiments, two materials may be deposited in
association with individual layers but additional materials may be
added to the overall structure by using different pairs of
materials on different layers. For example, some layers may include
copper and a dielectric while other layers may include nickel and
copper. After the formation of the structure is completed, the
copper may be removed as a sacrificial material which leaves behind
a nickel and dielectric structure with hollowed out regions and/or
a nickel, dielectric, and copper structure if copper is entrapped
by regions of nickel and/or dielectric material.
[0304] Additional embodiments may, for example, involve applying
some of the alternatives discussed in association with the seventh
embodiment to the eight embodiment while other embodiments may
involve combinations of the ninth through twelfth embodiments.
Other embodiments may be based on combinations of other embodiments
discussed in one section of the application with embodiments
disclosed in other sections of the application. It will be
understood by those of skill in the art that many additional
embodiments are possible. For example, in some alternative
embodiments additives may be placed in the ink or masking material
to harden the surface of the masking material to bring its hardness
closer to that of the deposited material or materials which may
result in improved planarization results (e.g. less smearing of
materials during lapping operations). As another example, some
embodiments may use a conductive masking material and replace it on
each layer with a different conductive material or with a
dielectric material. Some embodiments may etch into one or more of
the materials forming some layers in preparation for forming
interlacing elements in association with subsequent layers. Some
embodiments may use the masks not as deposition masks but instead,
or additionally, as etching masks. Some embodiments may not use any
planarization processes or may use them on less than all layers.
Some embodiments may use multiple structural materials (i.e.
materials that become part of the final structure) and or multiple
sacrificial materials. It will be understood by those of skill in
the art that supplemental operations may be used in conjunction
with the various embodiments and alternatives thereto. These
supplemental operations, for example may perform cleaning functions
between the primary operations, as discussed above, and/or may
perform activation functions, other treatment functions, detection
and monitoring functions, and the like.
[0305] In some embodiments, mesoscale and microscale multilayer
three-dimensional structures or devices are electrochemically
formed wherein one or more dielectric materials are incorporated
into the structure with the formation of each layer. Seed layers,
and potentially seed layer stacks of multiple materials (e.g.
adhesion layer material and seed layer material), are provided
during the formation of layers to ensure that a surface is capable
of electrochemically receiving deposits of material. On some layers
seed layer material is not deposited as a planar layer but is
instead deposited over exposed regions of a substrate and over one
or more previously deposited patterns of material on the layer.
Additional deposition of material occurs over the seed layer
material and planarization operations are used to remove seed layer
material deposited on previously deposited materials on the
layer.
[0306] In some embodiments three-dimensional structures are
electrochemically fabricated by depositing a first material onto
previously deposited material through voids in a patterned mask
where the patterned mask is at least temporarily adhered to a
substrate or previously formed layer of material and is formed and
patterned onto the substrate via a transfer tool patterned to
enable transfer of a desired pattern of precursor masking material.
In some embodiments the precursor material is transformed into
masking material after transfer to the substrate while in other
embodiments the precursor is transformed during or before transfer.
In some embodiments layers are formed one on top of another to
build up multi-layer structures. In some embodiments the mask
material acts as a build material while in other embodiments the
mask material is replaced each layer by a different material which
may, for example, be conductive or dielectric.
[0307] In some embodiments three-dimensional structures are
electrochemically fabricated by depositing a first material onto
previously deposited material through voids in a patterned mask
where the patterned mask is at least temporarily adhered to
previously deposited material and is formed and patterned directly
from material selectively dispensed from a computer controlled
dispensing device (e.g. an ink jet nozzle or array or an extrusion
device). In some embodiments layers are formed one on top of
another to build up multi-layer structures. In some embodiments the
mask material acts as a build material while in other embodiments
the mask material is replaced each layer by a different material
which may, for example, be conductive or dielectric.
[0308] It will be understood by those of skill in the art that
additional operations may be used in variations of the above
presented embodiments. These additional operations may perform
cleaning functions (e.g. between the primary operations discussed
above), they may perform activation functions and monitoring
functions.
[0309] Dispensed masking materials will preferably offer adequate
adhesion to the substrate and previously deposited materials onto
which they are dispensed. They will preferably be adequately
compatible with electrodeposition and/or etching baths as well as
plating and/or etching operations that will be employed during the
time the masking material is present such that entire layer
thicknesses may be deposited and/or sufficient depths etched
without need for replacing the mask though in some embodiments such
replacement may be acceptable. They are preferably compatible with
optimal cleaning solutions and processes as well as activation
solutions and processes, and the like. In embodiments where
deposition of adhesion layer materials and seed layer materials
will be applied to the masking material or the masking material
applied thereon, the masking material(s) are preferably sufficient
compatible such materials. In particular, it is preferable that the
masking material(s) need not require use of an adhesion layer
material. In some embodiments, preferred masking materials may be
dielectrics while in other embodiments masking materials may be
conductive materials. In some embodiments structural materials and
even sacrificial materials may need to be separable from the
masking materials while in other embodiments such ability to
separate the material may be unnecessary. Separation may occur by a
variety of operations (e.g. heating to melt, chemical dissolution,
electrochemical separation, breakdown by radiation exposure, or
burning out, and the like. Masking materials once dispensed may
become solidified masking materials by a variety of means curing
(e.g. polymerization by UV exposure or heat), phase change, solvent
removal (e.g. evaporation). In still other embodiments, colorants
or other additives may be included in the masking materials for a
variety of reasons. In other embodiments the materials may be
dissolvable by application of certain solvents.
[0310] 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.
* * * * *