U.S. patent application number 15/820982 was filed with the patent office on 2018-04-05 for methods for forming electronic devices from nanomaterials.
The applicant listed for this patent is Milara Incorporated. Invention is credited to Eugene Bonev, Ahmed Busnaina, Velimir Deric, Krassimir G. Marchev, Haniel Olivera, Krassimir D. Petkov.
Application Number | 20180096841 15/820982 |
Document ID | / |
Family ID | 58276472 |
Filed Date | 2018-04-05 |
United States Patent
Application |
20180096841 |
Kind Code |
A1 |
Petkov; Krassimir D. ; et
al. |
April 5, 2018 |
METHODS FOR FORMING ELECTRONIC DEVICES FROM NANOMATERIALS
Abstract
A multi-scale manufacturing system comprising a centrally
located multi-axis and multi-dimensional first manipulating
component associated with a housing for manipulating a substrate
and a template, a control subsystem coupled to the first
manipulating component for controlling movement thereof, a
pre-alignment subsystem for pre-aligning the substrate and the
template, an assembly station for applying nanomaterial to the
template, an alignment station for aligning the template and the
substrate together to form a workpiece assembly, and a transfer
subsystem for applying pressure to the workpiece assembly for
transferring the nanomaterial from the template to the
substrate.
Inventors: |
Petkov; Krassimir D.;
(Medway, MA) ; Busnaina; Ahmed; (Needham, MA)
; Marchev; Krassimir G.; (Sudbury, MA) ; Deric;
Velimir; (Franklin, MA) ; Olivera; Haniel;
(Fitchburg, MA) ; Bonev; Eugene; (Santa Clara,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Milara Incorporated |
Milford |
MA |
US |
|
|
Family ID: |
58276472 |
Appl. No.: |
15/820982 |
Filed: |
November 22, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15269752 |
Sep 19, 2016 |
|
|
|
15820982 |
|
|
|
|
62220113 |
Sep 17, 2015 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/67745 20130101;
B82Y 40/00 20130101; B29C 66/95 20130101; H01L 21/67167 20130101;
Y10S 977/84 20130101; H01L 21/02107 20130101; B29C 65/7802
20130101; H01L 29/0673 20130101; H01L 21/67207 20130101 |
International
Class: |
H01L 21/02 20060101
H01L021/02; B82Y 40/00 20060101 B82Y040/00 |
Claims
1. A method for fabricating a nanostructure from nanomaterial,
comprising providing a centrally located multi-axis and
multi-dimensional first manipulating component associated with a
housing for manipulating a substrate and a template, placing the
substrate in a pre-alignment subsystem for pre-aligning the
substrate, removing the substrate from the pre-alignment subsystem
and the placing the substrate in an alignment subsystem,
pre-aligning the template, removing the template from the
pre-alignment subsystem and then transferring the template to an
assembly subsystem, applying nanomaterial to the template in the
assembly subsystem to form the nanostructure, drying the template
once the nanomaterial is applied thereto in the assembly subsystem,
removing the template from the assembly subsystem with the first
manipulating component and then transferring the template to the
alignment subsystem, aligning the template with the substrate to
form a workpiece assembly, transferring the workpiece assembly with
the first manipulating component from the alignment subsystem to a
transfer subsystem, when in the transfer subsystem, transferring
the nanomaterial from the template to the substrate and then
separating the template from the substrate, with the first
manipulating component, removing the substrate and the template
from the transfer assembly, and controlling movement of the first
manipulating component between the subsystems.
2. The method of claim 1, further comprising, when the template is
processed in the assembly subsystem, placing the template in a
first reservoir containing the nanomaterial by a second
manipulating component, removing the template from the first
reservoir with the second manipulating component, translating the
second manipulating component horizontally, placing the template in
a second reservoir to air dry the template, removing the template
from the second reservoir with the second manipulating component,
and then transferring the template from the second manipulating
component to the first manipulating component.
3. The method of claim 2, further comprising, when the workpiece
assembly is processed in the transfer subsystem, applying pressure
to the workpiece assembly so as to transfer the nanomaterial from
the template to the substrate, and then applying air pressure
between the template and the substrate so as separate the template
from the substrate.
4. The method of claim 3, further comprising removing the substrate
from the transfer subsystem with the first manipulating component
and then transferring the substrate to a loading station.
5. The method of claim 4, further comprising removing the template
from the transfer subsystem with the first manipulating component
and then transferring the substrate to the loading station.
6. The method of claim 1, further comprising forming nanowells on
the template for holding the nanomaterial.
7. The method of claim 1, further comprising clustering the
pre-alignment subsystem, the alignment subsystem, the assembly
subsystem and the transfer subsystem about the first manipulating
component.
Description
RELATED APPLICATION
[0001] The present application is a Divisional patent application
based on U.S. patent application Ser. No. 15/269,752, filed Sep.
19, 2016, which claims priority to U.S. Provisional Patent
Application Ser. No. 62/220,113, filed Sep. 17, 2015, entitled
SYSTEMS AND METHODS FOR FORMING ELECTRONIC DEVICES FROM
NANOMATERIALS, the contents of which are herein incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] The fields of nanoscience and nanotechnology generally
concern the synthesis, fabrication and use of nanoelements and
nanostructures at atomic, molecular and supramolecular levels. The
nanosize of these elements and structures offers significant
potential for research and applications across the scientific
disciplines, including materials science, physics, chemistry,
computer science, engineering and biology. Biological processes and
methods, for example, are expected to be developed based entirely
on nanoelements and their assembly into nanostructures. Other
applications include developing nanodevices for use in
semiconductors, electronics, photonics, optics, materials and
medicine, and the like.
[0003] In particular electronic elements can be fabricated from
nanomaterials using certain selected techniques that are modified
to handle and manipulate the nanoscale material. One class of
materials that has garnered considerable interest are carbon
nanotubes. A carbon nanotube has a diameter on the order of
nanometers and can be several micrometers in length. These
nanoelements feature concentrically arranged carbon hexagons.
Carbon nanotubes can behave as metals or semiconductors depending
on their chirality and physical geometry.
[0004] Although carbon nanotubes have been assembled into different
nanostructures, only limited nanotools and fabrication methods for
their assembly have been developed. One obstacle has been the
manipulation of individual nanoelements, which is often inefficient
and tedious. This problem is particularly challenging when
assembling complex nanostructures that require selecting and
ordering millions of nanoelements across a large area.
[0005] Current nanostructure assembly has focused on dispersing and
manipulating nanoelements using atomic force or scanning tunneling
microscopic methods. Although these methods are useful for
fabricating simple nanodevices, neither is practical when selecting
and patterning, for example, millions of nanoelements for more
complex structures. As an alternative, lithographic methods have
been developed to modify substrates used for assembling
nanoelements. Examples of these lithographic methods include, but
are not limited to, electron-beam, ion-beam, extreme ultraviolet
and soft lithographies. These methods, however, remain incapable of
manipulating individual nanoelements. The development of
nanomachines or "nanoassemblers" which are programmed and used to
order nanoelements for their assembly holds promise, although there
have been few practical advancements with these machines to
date.
[0006] Self-assembly is a method for nanodevice fabrication that
does not require nanoelements to be individually manipulated. In
self-assembly, nanoelements are designed to naturally organize into
patterns by atomic, molecular and supramolecular particle
interactions. Self-assembled monolayers, for example, are formed by
the spontaneous arrangement of molecules into monomolecular layered
structures. These structures can be stabilized by van der Waals
forces or other forms of noncovalent bonding. Self-assembled
monolayers, however, have been problematic when used to transfer
nanoelements from one nanosubstrate to a recipient substrate.
Although particle interactions can be modified to affect their
transport, optical and electrical properties, controlling
nanoelement orientation is also a challenge in self-assembly
methods. Similarly, nanoscience has been incapable of manipulating
particle interactions to reproducibly assemble hundreds of
nanodevices.
[0007] Further, conventional manufacturing techniques have failed
to integrate nanoscale processes and nanomaterials into products.
Conventional prior art approaches such as inkjet printing, gravure
type printing, and screen printing have been used to create
structures using nanomaterials. However, these processes are quite
slow, are not readily scalable, do not provide sufficient high rate
throughput and typically only provide micron scale resolution.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to a system and method of
fabricating devices, including nanodevices, from nanomaterial. The
system of the present invention provides multiple different
processing stations or subsystems that communicate with a central
workpiece manipulating component, such as a multi-dimensional and
multi-axis robot arm. The system is adapted to apply nanomaterial
to a template and then transfer the nanomaterial from the template
onto a substrate. The system can perform this function by using a
multi-scale offset printing process or other known transfer
techniques suitable for use with nanoscale material.
[0009] The system and method of the present invention includes a
centrally located multi-axis and multi-dimensional manipulating
component mounted within a housing for manipulating a workpiece
during processing of the workpiece. The housing and manipulating
component form a manipulation station or subsystem. The system and
method of the present invention involves storing one or more
workpieces in a loading subsystem, station or module that is
coupled to the manipulating component housing. According to the
present invention, the workpieces are stored together or separately
in the loading station. The loading station can include a plurality
of vertical stacks or racks that have a plurality of shelves, each
adapted to hold and store a workpiece, such as a substrate and/or a
template.
[0010] The manipulating component removes a substrate from the
loading station and places the substrate in a pre-alignment station
or subsystem. The pre-alignment station pre-aligns the substrate to
a particular processing position according to known techniques, and
then the manipulating component removes the substrate and places
the substrate in an alignment station or subsystem for temporary
storage.
[0011] The manipulating component of the manipulation station then
retrieves a template from the loading station and then transfers
the template to the pre-alignment station where the template is
also pre-aligned prior to processing. The manipulating component
then retrieves the template and transfers the template to an
assembly station or sub-system. The assembly station includes a
housing having multiple tanks or reservoirs and a second
manipulating component for receiving the template from the
manipulating component of the manipulation station. The second
manipulating component receives the template from the first
manipulating component, and then orients the template vertically
for submersion in a first reservoir or tank having a fluid and
nanomaterial mixture contained therein. The second manipulating
element can function as a first electrode and a second electrode
can be electrically coupled to the first reservoir. The template is
submerged in the fluid and an electric field created within the
fluid between the two electrodes attracts the nanomaterial
contained therein to selected pre-defined areas of the template.
The second manipulating component then removes the template from
the first reservoir and then translates the template horizontally
until the template is positioned over a second adjacent reservoir.
The second manipulating component then moves vertically downwardly
placing the template in the second reservoir which functions as a
drying stage. Air jets disposed within the reservoir air dry the
template to remove any water therefrom.
[0012] The manipulating component of the manipulation station then
retrieves the template from the assembly station and then places
the template within the pre-alignment station so as to, once again,
pre-align the template. The manipulating component then transfers
the template from the pre-alignment station to the alignment
station. In the alignment station, the template and the substrate
are aligned with each other according to known techniques to form a
workpiece assembly.
[0013] The manipulating component then transfers the workpiece
assembly to a transfer module, where the substrate and the template
are pressed together employing suitable pressure applying
techniques so as to transfer the nanomaterial from the template to
the substrate. The substrate and the template are then separated by
suitable structure within the transfer station and then the
template and the substrate are separately transferred by the
manipulating component back to the loading station.
[0014] According to the present invention, a multi-scale
manufacturing system includes a centrally located multi-axis and
multi-dimensional first manipulating component associated with a
housing for manipulating a substrate and a template, a control
subsystem coupled to the first manipulating component for
controlling movement thereof, a pre-alignment subsystem for
pre-aligning the substrate and the template, an assembly station
for applying nanomaterial to the template, an alignment station for
aligning the template and the substrate together to form a
workpiece assembly, and a transfer subsystem for applying pressure
to the workpiece assembly for transferring the nanomaterial from
the template to the substrate. The multi-axis and multi-dimensional
manipulating component comprises a robotic arm.
[0015] The assembly station includes a first reservoir that
contains a fluid having nanomaterial and a second reservoir having
a plurality of air jets for air drying the template. The assembly
station further comprises a second manipulating component for
manipulating the template when received from the first manipulating
component, wherein the second manipulating component places the
template into the first reservoir containing the nanomaterial for
applying the nanomaterial thereto, and then subsequently places the
template into the second reservoir for drying the template.
[0016] Further, the housing of the multi-axis and multi-dimensional
manipulating component has a hexagonal shape, and the control
subsystem, the pre-alignment subsystem, the alignment subsystem,
the assembly subsystem and the transfer subsystem are clustered
about the housing.
[0017] The present invention is also directed to a method for
fabricating a nanostructure from nanomaterial. The fabrication
method includes providing a centrally located multi-axis and
multi-dimensional first manipulating component associated with a
housing for manipulating a substrate and a template, placing the
substrate in a pre-alignment subsystem for pre-aligning the
substrate, removing the substrate from the pre-alignment subsystem
and the placing the substrate in an alignment subsystem,
pre-aligning the template, removing the template from the
pre-alignment subsystem and then transferring the template to an
assembly subsystem, applying nanomaterial to the template in the
assembly subsystem to form the nanostructure, drying the template
once the nanomaterial is applied thereto in the assembly subsystem,
and removing the template from the assembly subsystem with the
first manipulating component and then transferring the template to
the alignment subsystem. The method also includes aligning the
template with the substrate to form a workpiece assembly and
transferring the workpiece assembly with the first manipulating
component from the alignment subsystem to a transfer subsystem.
When in the transfer subsystem, the nanomaterial is transferred
from the template to the substrate and then the template is
separated from the substrate. The substrate and the template are
then transferred from the transfer assembly by the first
manipulating component.
[0018] According to the present invention, when the template is
processed in the assembly subsystem, the template is placed in a
first reservoir containing the nanomaterial by a second
manipulating component, the template is removed from the first
reservoir with the second manipulating component and is translated
horizontally thereby, and then the template is placed in a second
reservoir to air dry the template. The template is removed from the
second reservoir with the second manipulating component, and then
transferred from the second manipulating component to the first
manipulating component. When the workpiece assembly is processed in
the transfer subsystem, the transfer assembly applies pressure to
the workpiece assembly so as to transfer the nanomaterial from the
template to the substrate. Subsequently, air pressure is applied
between the template and the substrate so as separate the template
from the substrate.
[0019] The present invention also contemplates forming nanowells on
the template for holding the nanomaterial. Also, the present
invention involves clustering the pre-alignment subsystem, the
alignment subsystem, the assembly subsystem and the transfer
subsystem about the first manipulating component.
BRIEF DESCRIPTION OF THE FIGURES
[0020] These and other features and advantages of the present
invention will be more fully understood by reference to the
following detailed description in conjunction with the attached
drawings in which like reference numerals refer to like elements
throughout the different views. The drawings illustrate principals
of the invention and, although not to scale, show relative
dimensions.
[0021] FIG. 1 is a perspective view of a multi-scale manufacturing
system for generating devices, including nanodevices, from
nanomaterial according to the teachings of the present
invention.
[0022] FIG. 2 is a top view of the multi-scale manufacturing system
of FIG. 1 according to the teachings of the present invention.
[0023] FIG. 3A is a schematic representation of a process for
fabricating a damascene template suitable for use with the system
of the present invention.
[0024] FIG. 3B is a schematic representation of a cross-section of
a damascene template suitable for use with the system of the
present invention.
[0025] FIG. 4 is a schematic representation of another embodiment
of a template suitable for use with the present invention.
[0026] FIG. 5 is a schematic block diagram illustrating the
processing steps for forming a nanodevice or an electronic device
on a substrate or template.
DETAILED DESCRIPTION
[0027] The present invention is described in detail below. First,
we set forth definitions of selected terms that may be used
throughout the specification and associated claims.
[0028] The articles "a" and "an" are used herein to refer to one or
to more than one (i.e., to at least one) of the grammatical object
of the article. By way of example, "an element" means one element
or more than one element.
[0029] The term "or" is used herein to mean, and is used
interchangeably with, the term "and/or," unless context clearly
indicates otherwise.
[0030] The term "about" is used herein to mean a value - or +20% of
a given numerical value. Thus, "about 60%" means a value of between
60- (20% of 60) and 60+ (20% of 60) (i.e., between 48 and 70).
[0031] As used herein, the term "nanomaterial" is intended to
include natural and synthetic nanoscale materials or structures,
such as nanoparticles, fullerenes such as nanotubes, including
carbon or silicon nanotubes, polystyrene and PLGA polymer, PSL or
silica nanoparticles, metallic particles, polymers, graphene, and
the like. Examples of nanoparticles include nanocrystals, quantum
dots, nanorods, and nanowires, biological and chemical material,
metallic particles, and other known materials and structures. The
nanomaterial can be used to construct nanodevices, such as
nanoelements, nanostructures, and/or nanofilms, or devices of
larger scale. Further, the nanomaterial can be used to form an
interconnect according to the present invention. The nanotubes can
be multi walled or single walled nanotubes (SWNT) and can behave
like metals as in known in the art. Examples of interconnect
structures formed using carbon nanotubes are described in U.S. Pat.
No. 8,937,293, the contents of which are herein incorporated by
reference.
[0032] As used herein, the term "nanoscale" refers to a size or
dimension of an object or a portion of an object in the range from
about 1 nm to about 1000 nm. The term "microscale" as used herein
refers to a size or dimension of an object or a portion of an
object in the range from about 1 .mu.m to about 1000 .mu.m.
[0033] A "nanofilm" as used herein means a film having a thickness
in the nanoscale range and a surface area that is any size. A
nanofilm according to the present invention is deposited by a
method of the invention, and the nanofilm can be used either as an
end product, as deposited, or as a raw material that is gathered
and stored or transported for later use, such as incorporation into
a circuit or other device. While the nanoelement assemblies
according to the invention are generally flat, and are thus termed
nanofilms, they may also take a more compact form (e.g., when
deposited in a narrow nanoscale trench) and can be termed
"nanowires".
[0034] The term "substrate" as used herein refers to a solid
material upon which nanomaterial is deposited to form a
nanostructure or nanofilm or other like nanoscale structure by a
method according to the present invention. A substrate is generally
flat but can have any dimensions according to its anticipated use.
The substrate can be of any suitable material, but usually the
substrate contains a material such as silicon, silicon oxide or
dioside, or a hydrophobic polymer such as parylene-C or
polyethylene terephthalate (PET). The substrate has a hydrophobic
surface that can be rendered hydrophilic by a plasma etching
technique, if desired. The substrate can be homogeneous throughout
or it can have a layered structure. If layered, the uppermost
substrate layer is preferably hydrophobic.
[0035] The present invention is directed to a multi-scale offset
printing process and associated systems based on directed assembly
and nanomaterial transfer from a template to a substrate. A
reusable template, such as a damascene template, can be employed
for high-yield and high-rate assembly and transfer of nanomaterial.
The template can be fabricated using a hard substrate, such as a
silicon wafer, or a flexible substrate, such as polyimide or PET,
thereby enabling continuous manufacturing systems, such as a
roll-to-roll system.
[0036] Electrophoresis can be used to assemble various nanodevices,
such as nanoelements or nanostructures such as polymer
nanoparticles, silica nanoparticles, carbon nanotubes (single and
multi-wall) or organic molecules on the template. These techniques
can be performed with a high degree of control, and transfer
printing can be used to transfer the assembled nanoelements from
the template to a recipient substrate. Furthermore, to ensure
uniformity during assembly the templates can be reusable and can be
designed so that all micro/nano conductive patterns have the same
or similar electrical properties during the assembly stage.
[0037] The present invention provides, at least in part, a system
and method to form, create, or manufacture, and assemble, one or
more nanodevices from nanomaterial using a patterned substrate, in
a controlled and precise manner using selected electrophoretic
techniques, such as DC electrophoresis. This method can assemble
nanomaterial, such as for example nanotubes and nanoparticles, over
larger dimensions (e.g., nanoscale, microscale or larger such as
macroscale) than previously possible, and in a relatively shorter
period of time (e.g., minutes). Furthermore, previous techniques
required using wires having diameters in at least the micron range
for generating the electric field. The present invention employs,
however, nanoscale conductors that align and assemble nanoelements
by DC electrophoresis. An example of nanoscale conductors that can
be employed to directly assemble nanomaterial on a substrate
employing DC electrophoresis is disclosed in U.S. Pat. No.
8,668,978, the contents of which are herein incorporated by
reference.
[0038] The multi-scale manufacturing system 10 of the present
invention is illustrated in FIGS. 1 and 2. The multi-scale system
is intended to manufacture nanodevices, such as nanoelements,
nanostructures, nanofilms and other like nanoscale products, in
large quantities in relatively short periods of time without
requiring high capita costs typically associated with the
manufacture of electronic components. For the sake of simplicity,
we simply refer to these various nanoscale products produced by the
illustrated multi-scale system as nanodevices or nanostructures in
the following disclosure.
[0039] The multi-scale manufacturing system 10 includes a centrally
located workpiece manipulating subsystem or module 12 that is
housed within a central frame or housing 14. The housing includes a
multi-axis and multi-dimensional manipulating component 16, such as
a robotic arm, that is adapted to receive, handle and transfer
workpieces processed by the system 10. The manipulating component
is preferably adapted to handle workpieces, such as substrates and
templates, employed in the system with a relatively high degree of
precision and dexterity. In this regard, the manipulating component
can employ high precision motion controllers and servo motors that
allow for the relatively smooth handling of components. An example
of a suitable manipulating component suitable for use with the
present invention is the Diamond H3 handling robot manufactured and
sold by Milara, Inc., USA. The housing 14 can have any selected
shape or configuration, and is specifically configured to allow
other subsystems to be clustered around or about the central
housing. According to a preferred embodiment, the housing 14 has a
hexagonal shape, although those of ordinary skill in the art will
readily recognize that other configurations that promote the
clustering of subsystems about a central housing can also be
employed. The remaining subsystems can be disposed immediately
adjacent to or can contact the central housing 14.
[0040] The multi-scale manufacturing system 10 includes a control
station or subsystem 70 that can include computing suitable
hardware and software for operating one or more components or
subsystems of the multi-scale manufacturing system 10. The control
station can include for example a computing device, such as a
computer, a user interface such as a display, and an input device
such as a keyboard and mouse. The control station allows an
operator to program the system 10 to process a selected number of
substrates according to one or more defined sequences. Further
detailed information regarding the control station is provided
below.
[0041] The illustrated multi-scale manufacturing system 10 includes
a workpiece loading and storage station or subsystem 20. The
workpieces stored and loaded in the loading station include
substrates and/or templates, and can be housed in one or more
vertically extending racks, where each rack includes a plurality of
slots, each of which is adapted to house or store a selected
workpiece. If the workpiece is a template, then the template is
used to mount thereto the nanomaterial. If the workpiece is a
substrate, then the substrate can function as the receiving or
transferring member.
[0042] The manipulating component 16 initially moves for example a
substrate from one of the stacks in the loading station 20 to the
pre-alignment station or subsystem 30 so as to pre-align the
substrate. The pre-alignment station 30 is necessary to help ready
the substrate for processing by locating and precisely positioning
the substrate for subsequent processing. Examples of pre-alignment
modules suitable for use with the present invention include the
line of pre-aligner systems manufactured and sold by Logosol,
Inc.
[0043] The manipulating component 16 then retrieves the pre-aligned
substrate and removes it from the pre-alignment station 30 and
transfers the substrate to the alignment station or subsystem 40.
The alignment station 40 can employ high precision viewing optics
to help locate and/or view selected locating marks and hence align
the substrate with a high degree of precision. The substrate is
aligned in this module with a subsequently loaded template as part
of a nanoscale offset printing process. The system can employ
optical markers and the like on the substrate to ensure that the
substrate is initially disposed in a suitable alignment position
and properly aligned with the template. The substrate can be
retained within the module by any suitable pneumatic system that
can apply a selected vacuum to the substrate while awaiting
subsequent loading of the template. Examples of aligner systems,
commonly referred to as mask aligners, suitable for use with the
present invention include the NXQ8000 series mask aligner systems
manufactured and sold by Neutronix, Inc.
[0044] According to one aspect of the present invention, a bottom
chuck portion of the alignment station 40 can have a platen design
with embedded pins. The pins lift the substrate or template from
the bottom chuck to an upper chuck and pneumatically held therein
for temporary storage. The pins can be operated through any
selected pneumatic system. Further, the workpieces (e.g.,
substrates and templates) can be handled at the edges to ensure a
relatively clean and safe transfer and manipulation of the
workpiece. Since the substrate can be temporarily stored in the
upper chuck portion of the alignment station, the template and the
substrate can be introduced to the station at different times by
the manipulating component 16, which functions as a first
manipulating component.
[0045] The manipulating component 16 then retrieves a template from
the pre-alignment station 30 which can be adapted to store a
plurality of templates in an upper portion of the housing.
Alternatively, the templates can be stored in the loading station
20. The templates can be multi-layered structures that can have
formed thereon selected patterns that are adapted to house and
store the nanomaterial during the formation of the nanostructures.
The template is also moved to a lower portion of the housing of the
pre-alignment station where it is pre-aligned, similar to the
substrate.
[0046] The templates as discussed herein can be formed according to
known techniques. For example, the present invention contemplates
the use of a template that employs a patterned substrate, such as a
nanosubstrate. The nanosubstrate can be formed in a controlled and
precise manner using known electrophoretic techniques. According to
one practice, a template can be formed using trenches or nanowells
to hold and retain the nanomaterial for subsequent transfer to the
substrate. Examples of templates of this type are shown and
described in U.S. Publication No. 2009/0087622, the contents of
which are herein incorporated by reference. The templates of the
present invention can be reused according to known techniques.
[0047] The present invention also contemplates the use of a highly
reusable, relatively flat damascene template, such as those shown
and described in U.S. Publication No. 2014/0318967, the contents of
which are herein in corporate by reference. As shown in FIGS. 3A
and 3B, a topographically flat damascene template 80 is shown and
can be used to assist in the assembly and transfer of nanoelements
formed from nanomaterial. Patterned assemblies of nanodevices such
as nanoparticles and carbon nanotubes can be produced on the
damascene template and transferred to desired locations on a
receptor substrate, with resulting high density and good uniformity
of the patterned nanoelements. The transfer of assembled SWNTs or
other nanoelements onto a flexible substrate can be performed
without any intermediate steps and without a need for sacrificial
films. The illustrated damascene template 80 is reusable and can be
employed in a high rate assembly and transfer process.
Additionally, the damascene template 80 is compatible with various
types of nanomaterials and nanoelements. The products and methods
of the invention can provide advancements in high rate
manufacturing of flexible devices, such as electrical and optical
devices, such as display devices and strain gauges, as well as
biosensors and chemical sensors. FIG. 3A is a schematic diagram of
a damascene template fabrication process and FIG. 3B is a schematic
representation of a cross-section of a suitable embodiment of the
damascene template suitable for use with the present invention.
[0048] FIG. 3A is a schematic illustration of a process of forming
a damascene template 80. Initially, a metallic layer (e.g., Au or
W) is deposited on an electrically insulating substrate, and
lithography is carried out to create a desired pattern for
nanoelement assembly. Subsequently, partial etching of the metallic
layer is conducted to form raised features having dimensions on the
micrometer and/or nanometer scale. The raised features protrude
above the plane of the rest of the metallic conductive layer. A
thick layer of insulating material (e.g., SiO.sub.2 or SiN.sub.4)
is blanket deposited on these patterned structures. A chemical
mechanical polishing (CMP) process is then carried out to remove
the insulating material until it is essentially coplanar with the
top surfaces of the raised metal features, and until the top
surfaces of the raised metal features are coplanar with one another
across the substrate, or a portion of the substrate.
[0049] Thus, the resulting damascene template 80 has nano/micro
features connected by a conductive film underneath an insulator
(second insulating layer), which enables all of the micro/nano
structures on the whole substrate, or a desired region of the
substrate, to have equal potential during electrophoretic assembly.
Preferred materials are gold for the metallic layer and
PECVD-deposited silicon dioxide for the insulating layer.
[0050] FIG. 3B is a cross-sectional view of the damascene template
80 used with the current multi-scale manufacturing system 10. The
template 80 includes a substrate 82 that forms a base layer and is
formed of electrically insulating material, such as silicon or a
suitable polymer material. The substrate 82 is essentially planar
on at least one surface, or is entirely planar, and can be either
generally or substantially rigid or can be flexible, so as to bend
or conform to a desired shape. The substrate 82 can have any
suitable size or shape required for the particular application, but
generally has a thickness of between about 1 .mu.m to about 10
.mu.m, or about 100 .mu.m or less, or about 1000 .mu.m or less, and
a surface area on a planar surface of about 0.005 mm.sup.2 or more,
up to several cm.sup.2. The substrate 82 can be fabricated from
electrically insulating materials including silicon, silicon
dioxide, organic polymers including epoxies and liquid crystal
polymers, or a photoresist material such as SU-8.
[0051] The illustrated template 80 also includes a first insulating
layer 84 formed on top of the substrate 82. The first insulating
layer 84 can be formed from any suitable insulating material, such
as SiO.sub.2, SiN.sub.4, or a polymer, which is deposited or
induced to form on the surface of the substrate on which a
conductive layer is deposited and nanoelements are assembled. The
thickness of the first insulating layer 84 is, for example, in the
range between about 10 nm to about 10 .mu.m, or between about 20 nm
to about 1 .mu.m, or between about 30 nm to about 500 nm, or
between about 5 nm to about 500 nm, or between about 40 nm to about
250 nm, or between about 50 nm to about 100 nm. The first
insulating layer 84 can also be generally planar in structure and
can extend over the entire substrate layer 82 or a portion of the
substrate layer 82. The layer 84 prevents current leakage from an
adjacent conductive layer 88 into the substrate 82 during
electrophoretic assembly.
[0052] The template 80 also employs an optional adhesion layer 86
that is deposited onto the first insulating layer 84. The adhesion
layer 86 provides improved adhesion of the conductive layer 88 to
the first insulating layer 84, so that the conductive layer remains
in place when voltage is applied to the conductive layer during
electrophoretic assembly. Suitable materials for the adhesion layer
86 include chromium, titanium, titanium dioxide, titanium nitride,
tantalum, tantalum nitride, tungsten, and combinations thereof. The
thickness of the adhesion layer can be, for example, from about 3
nm to about 50 nm.
[0053] The damascene template 80 also includes a conductive layer
88 formed of a conductive metal that is deposited on the adhesion
layer 86 if present or directly on the first insulating layer in
embodiments with no adhesion layer. Suitable materials for the
conductive layer 88 include metals such as gold, silver, tungsten,
aluminum, titanium ruthenium, copper, and combinations or alloys
thereof. The conductive layer 88 can include in essence two
portions or layers, including a planar base layer having a
thickness in the range between about 50 nm to about 100 .mu.m, and
a plurality of raised features 92 which can extend at least
temporarily during formation of the template above the plane of the
base layer (for example, from about 10 nm to about 10 .mu.m in
height) and which have electrical continuity with one another
through the base layer of the conductive layer.
[0054] A second insulating layer 94 can be formed and initially
deposited over the entire conductive layer 88, including the raised
features 92, and then planarized by chemical mechanical polishing
so as to render coplanar the upper exposed surfaces of the second
insulating layer 94 and the raised features. The thickness of the
second insulating layer 94 can be, for example, from about 10 nm to
about 10 .mu.m and is generally about the same as the height of the
raised metal features. In some embodiments, the thickness of the
second insulating layer 94 and the raised features 92 is the same
to within +/-1 .mu.m, 100 nm, 10 nm or even 5 nm or 2 nm. The
second insulating layer 94 fills the spaces between the raised
features and provides electrical insulation in those regions which
inhibits the assembly of nanoelements during electrophoretic
assembly. Suitable materials for the second insulating layer
include SiO.sub.2, SiN.sub.4, Al.sub.2O.sub.3, organic polymers,
and combinations thereof.
[0055] In order to further inhibit nanoelement assembly in the
insulated regions, those regions are preferably coated with a
hydrophobic coating 96. The hydrophobic coating 96 is preferably a
self-assembled monolayer (SAM) of an alkyl silane (which covalently
bonds to SiO.sub.2 if that material is used in the second
insulating layer). The silane can be, for example,
octadecyltrichlorosilane, or a similar silane having an alkyl chain
of about 8-24 carbons in length. The preferred thickness of the
hydrophobic coating 96 is one molecule, though it can also be more
than one molecule. The purpose of the hydrophobic coating is to
prevent the assembly of nanoelements on the exposed surface of the
second insulating layer 94; as such, it only needs to render the
exposed surface of the second insulating layer hydrophobic, and to
be selectively bound to the second insulating layer and preferably
not bound to the exposed surface of the conducting layer, where
nanoelements are to be assembled. The hydrophobic coating has a
contact angle from about 90.degree. to about 110.degree., and
preferably about 100.degree.. In contrast, the exposed metal
conductive layer surface has a contact angle of from 15.degree. to
21.degree., and preferably about 18.degree..
[0056] Fabrication techniques for making the illustrated damascene
template 80 are known to the skilled person. Such techniques as
micro- and nanopatterning can be carried out by e-beam lithography,
photolithography, and nano-imprint lithography. Deposition of
metals can be performed by sputtering, chemical vapor deposition,
or physical vapor deposition. Deposition of polymers and resists
can be performed by spin coating. SiO.sub.2 as the second
insulating layer can be deposited by plasma enhanced chemical vapor
deposition (PECVD). Etching of the second insulating layer and
metal conductive layer can be by ion milling, ion-coupled plasma
(ICP) and reactive ion etching (RIE). The two-dimensional pattern
of the raised features of the metal conductive layer, and
correspondingly the pattern of assembled nanoelements, can be any
pattern that can be established using lithographic techniques,
including linear features that are straight, curved, or
intersecting as well as geometric shapes such as circles,
triangles, rectangles, or dots. The raised features can have a
width in the range from about 10 nm to about 100 .mu.m, and a
length from about 10 nm to several cm (e.g., the full diameter of a
wafer).
[0057] The damascene template topography can impact the efficiency
and yield of the assembly and transfer processes. Ideally a flat
topography is used, which provides a uniform electric field from
edge to the center of the electrodes, with minimal variation and
facilitating uniform assembly. In addition, a non-flat topography
can result in uneven transfer, creating indentations on the
transfer substrate surface. To achieve a flat topography, the end
point detection in the CMP process needs to be relatively precise.
For example, sufficiently precise control can be achieved by
determining the time period required for CMP based on the
associated material removal rate.
[0058] As shown in FIG. 4, the damascene template for assembling
nanoelements may involve both nanoscale and micron scale geometries
and employ electrophoresis to drive directed assembly. That is,
nanoscale and micron scale electrodes can be patterned on an
insulator such that the nanoscale metal electrodes are connected to
micron scale counterparts which are then connected to a large metal
pad. During assembly using previous template designs, when a
potential is applied to the large pad, there is a large potential
drop across the length of the nanowires due to the increased
resistivity of the nanoscale features. This potential drop has a
significant impact on the assembly results, and can yield a
non-uniform assembly on various portions of the template. With use
of the illustrated damascene template, however, since all the
nanoscale and micron scale electrodes are connected to the metal
sheet underneath the insulator, when a potential is applied to the
metal sheet during nanoelement assembly there is negligible
variation in the electric potential between the micron scale and
nanoscale electrodes.
[0059] Further details of the process and systems that can be
employed to create the templates and nanostructures are set forth
and illustrated in U.S. Pat. No. 8,784,673 of Xiong et al., U.S.
Pat. No. 8,668,978 of Malima et al., and U.S. Pat. No. 8,703,501 of
Mead et al., the contents of which are herein incorporated by
reference. Electrophoresis is employed to achieve directed assembly
of the nanoelements, while a transfer printing method is employed
to transfer the assembled nanoelements onto the surface of the
substrate.
[0060] With reference again to FIGS. 1 and 2, the manipulating
component 16 then moves the template from the pre-alignment station
30 to the assembly station or subsystem 50. The assembly module
includes a plurality of sections that are adapted to perform
different processing steps. For example, the assembly module can
include one or more tanks or reservoirs that can include a mixture
that contains nanomaterial. According to the present invention, the
manipulating component 16 transfers the template to the assembly
module, where a second manipulating component receives the template
from the first manipulating component. The second manipulating
component orients the template so as to submerge the template into
a first reservoir that contains a nanomaterial solution. The
solution can contain water and the nanomaterial, although solvents
and solutions can also be used as would be obvious to one of
ordinary skill in the art. The properties of the solution (such as
pH) are adjusted such that the nanoelements have a selected charge.
A DC voltage is applied between the template and a second counter
electrode. The polarity of the applied voltage is opposite to that
of the nanoelements or template. The electric field can be applied
through the second manipulating component directly to the template
and the second or counter electrode can be placed or disposed in
the receptacle. The nanomaterial within the solution is deposited
or attracted to selected surface features formed on or in the
template through the applied electric field. The charged
nanoelements are selectively assembled on the electrode surface and
not on the insulator. With the potential still being applied, after
assembly, the template and the counter electrode are withdrawn from
the suspension in the first reservoir at a selected speed, such as
a constant speed although the speed can also be variable. The
potential is still applied to the template during withdrawal of the
template from the receptacle or reservoir, since the hydrodynamic
drag on the assembled nanoparticles is strong enough to remove them
if the potential is not applied.
[0061] After the template is removed from the nanomaterial solution
within the receptacle, the template is transferred to a dryer stage
formed within a second tank or reservoir of the assembly station
for drying the template after it is removed from the first
receptacle. Once dried, the second manipulating component transfers
the template with nanomaterial back to the first manipulating
component 16 where the template is once again transferred to the
pre-alignment station 30. Once the template is pre-aligned, the
template is then transferred to the alignment station 40 where it
is accurately aligned with the substrate. This process is similar
to the process employed during the manufacture of semiconductors.
In the alignment station 40, the template and the substrate are
aligned together.
[0062] Once the substrate and template are aligned together, the
manipulating component 16 transfers the combined workpiece assembly
(e.g., substrate and template) to the transfer station or subsystem
60. In the transfer station 60, a press system can be employed to
press together the adjacent template and substrate of the workpiece
assembly by applying a selected amount of heat and pressure. For
example, the pressure can range between about 50 psi and about 100
psi. The forced mechanical contact between the two substrates
allows the nanostructure formed on the template to be transferred
to the receiving or transfer substrate. The transfer efficiency of
the transfer printing process is primarily determined by the
differential adhesion force between the template and the substrate.
If the adhesion force between the nanoelement and template is
smaller than the adhesion force between the nanoelement and
substrate (or recipient) then the nanoelements are transferred onto
the recipient surface. If the contrary is true, the nanoelements
remain on the template surface after the transfer process. During
transfer, the hydrophobic layer 96 plays the additional role of
being an anti-stiction layer when the damascene template is
separated from the flexible substrate during transfer. This
transfer process does not significantly affect the template, which
enables the damascene template to be reused for the
assembly-transfer process without additional surface modification
for at least several hundred cycles. Also, no additional processes
such as stripping, patterning, or sacrificial layer
removal/deposition are needed.
[0063] The template is then separated from the substrate, such as
through selected air jets, and then the manipulating component 16
removes the substrate from the transfer station 60 and places the
substrate with the corresponding nanostructure in the substrate
storage and loading station 20 for storage and subsequent use.
[0064] FIG. 5 is a schematic block diagram representation setting
forth the processing and fabrication steps involved in forming a
nanostructure on a template, which is then transferred to a
receiving substrate. At the outset, the manipulating component 16
of the multi-scale manufacturing system 10 retrieves a substrate
from the loading station 20, step 102, and places the substrate in
the pre-alignment station 20. The pre-alignment station 30
pre-aligns the substrate to a particular processing position
according to known techniques, step 104. The manipulating component
16 then removes the substrate from the pre-alignment station and
places the substrate in the alignment station 40, step 106. The
substrate can be temporarily stored within the alignment station
pending retrieval and processing of the template.
[0065] The manipulating component 16 of the manipulation station 12
then retrieves a template from a suitable template storage
facility, such as from storage structure contained within the
pre-alignment station, step 108. If the template is stored in the
pre-alignment station, then the manipulating component 16 moves the
template to the pre-alignment portion of the station 30 where the
template is pre-aligned prior to further processing, step 110. The
manipulating component 16 then retrieves the template and transfers
the template to the assembly station 50. The assembly station 50
includes a housing having multiple tanks or reservoirs and a second
manipulating component for receiving the template from the first
manipulating component 16 of the manipulation station 12. The
second manipulating component receives the template from the
manipulating component 16, and then orients the template vertically
for submersion in the first reservoir having a fluid and
nanomaterial mixture contained therein. The second manipulating
element can function as a first electrode and a second electrode
can be electrically coupled to the first reservoir. The template is
submerged in the fluid and an electric field created within the
fluid between the two electrodes attracts the nanomaterial
contained therein to selected pre-defined areas of the template.
The second manipulating component then removes the template from
the first reservoir and then translates the template horizontally
until the template is positioned over a second adjacent reservoir.
The second manipulating component then moves vertically downwardly
placing the template in the second reservoir which functions as a
drying stage. Air jets disposed within the reservoir air dry the
template to remove any water therefrom, step 112.
[0066] The manipulating component 16 of the manipulation station 12
then retrieves the template from the assembly station 50 and then
places the template within the pre-alignment station 30 so as to,
once again, pre-align the template, step 114. The manipulating
component 16 then transfers the template from the pre-alignment
station 30 to the alignment station 40. In the alignment station,
the template and the substrate are aligned with each other
according to known techniques to form a workpiece assembly, step
116.
[0067] The manipulating component 16 then transfers the workpiece
assembly to the transfer station 60, where the substrate and the
template are pressed together employing suitable pressure applying
techniques so as to transfer the nanomaterial from the template to
the substrate, step 118. The substrate and the template are then
separated by suitable structure within the transfer station and
then the template and the substrate are separately transferred by
the manipulating component back to the loading station 20.
[0068] One or more of the above-described acts or function steps
can be encoded as computer-executable instructions executable by
processing logic, e.g., in a programmed electronic device, such as
provided in the control station 70. The computer-executable
instructions may be stored on one or more non-transitory computer
readable media. The electronic device may retrieve executable
instructions from a computer-readable media and may execute the
instructions using a processing device to perform one or more
operations for implementing aspects of exemplary embodiments
described herein. The electronic device may take many forms,
including but not limited to a computing device, computer,
workstation, server, network computer, optical computer, Internet
appliance, mobile device, a tablet computer, application specific
processing device, etc. For example, an alternative implementation
of electronic device may have fewer components, more components, or
components arranged in various configurations. The components of
the computing device may be implemented using hardware based logic
and/or logic that is a combination of hardware and software based
logic (e.g., hybrid logic).
[0069] The computing device can include a processor that may
include hardware based logic or a combination of hardware based
logic and software to execute machine-readable instructions on
behalf of any suitable electronic device. The processor may include
logic that may interpret, execute, and/or otherwise process
information contained in, for example, a memory element. The
information may include computer-executable instructions and/or
data that may implement one or more embodiments of the invention.
The processor may also comprise a variety of homogeneous or
heterogeneous hardware. The hardware may include, for example, some
combination of one or more processors, microprocessors, field
programmable gate arrays (FPGAs), application specific instruction
set processors (ASIPs), application specific integrated circuits
(ASICs), complex programmable logic devices (CPLDs), graphics
processing units (GPUs), or other types of processing logic that
may interpret, execute, manipulate, and/or otherwise process the
information. The processor may include a single core or multiple
cores. Moreover, the processor may include a system-on-chip (SoC)
or system-in-package (SiP).
[0070] The electronic device may include one or more tangible
non-transitory computer-readable storage media for storing one or
more computer-executable instructions or software that may
implement one or more embodiments of the invention. The
non-transitory computer-readable storage media may be, for example,
memory or storage. The memory may comprise a RAM that may include
RAM devices that may store the information. The RAM devices may be
volatile or non-volatile and may include, for example, one or more
DRAM devices, flash memory devices, SRAM devices, zero-capacitor
RAM (ZRAM) devices, twin transistor RAM (TTRAM) devices, read-only
memory (ROM) devices, ferroelectric RAM (FeRAM) devices,
magneto-resistive RAM (MRAM) devices, phase change memory RAM
(PRAM) devices, or other types of RAM devices.
[0071] One or more electronic devices may include a virtual machine
(VM) for executing the instructions loaded in memory. A virtual
machine may be provided to handle a process running on multiple
processors so that the process may appear to be using only one
computing resource rather than multiple computing resources.
Virtualization may be employed in the electronic device so that
infrastructure and resources in electronic device may be shared
dynamically. Further, as is known in the art, multiple VMs may be
resident on a single electronic device.
[0072] The computing or electronic device may also include a
network interface to interface to a Local Area Network (LAN), Wide
Area Network (WAN) or the Internet through a variety of connections
including, but not limited to, standard telephone lines, LAN or WAN
links (e.g., T1, T3, 56kb, X.25), broadband connections (e.g.,
integrated services digital network (ISDN), Frame Relay,
asynchronous transfer mode (ATM), wireless connections (e.g.,
802.11), high-speed interconnects (e.g., InfiniBand, gigabit
Ethernet, Myrinet) or some combination of any or all of the above.
The network interface may include a built-in network adapter,
network interface card, personal computer memory card international
association (PCMCIA) network card, card bus network adapter,
wireless network adapter, universal serial bus (USB) network
adapter, modem or any other device suitable for interfacing
electronic device to any type of network capable of communication
and performing the operations described herein.
[0073] The electronic device may include one or more input devices,
such as a keyboard, a multi-point touch interface, a pointing
device (e.g., a mouse), a gyroscope, an accelerometer, a haptic
device, a tactile device, a neural device, a microphone, or a
camera that may be used to receive input from, for example, a user.
Note that the electronic device may include other suitable I/O
peripherals. The input device may allow a user to provide input
that is registered on a display device. A graphical user interface
(GUI) may be shown on the display device.
[0074] A storage device may also be associated with the electronic
device. The storage device may be accessible to the processor via
an I/O bus. The information may be executed, interpreted,
manipulated, and/or otherwise processed by the processor. The
storage device may include, for example, a storage device, such as
a magnetic disk, optical disk (e.g., CD-ROM, DVD player),
random-access memory (RAM) disk, tape unit, and/or flash drive. The
information may be stored on one or more non-transient tangible
computer-readable media contained in the storage device. This media
may include, for example, magnetic discs, optical discs, magnetic
tape, and/or memory devices (e.g., flash memory devices, static RAM
(SRAM) devices, dynamic RAM (DRAM) devices, or other memory
devices). The information may include data and/or
computer-executable instructions that may implement one or more
embodiments of the invention. The storage device may be used for
storing selected application software programs.
[0075] The storage device may further store applications, and the
electronic device can be running any selected operating system
(OS). Examples of suitable operating systems may include the
Microsoft.RTM. Windows.RTM. operating systems, the Unix and Linux
operating systems, the MacOS.RTM. for Macintosh computers, an
embedded operating system, such as the Symbian OS, a real-time
operating system, an open source operating system, a proprietary
operating system, operating systems for mobile electronic devices,
or other operating system capable of running on the electronic
device and performing the operations described herein. The
operating system may be running in native mode or emulated mode.
The storage device may also store templates associated with
applications. The templates associated with applications may be
combined and the combination applied to a file or a file storage
structure created using applications, as discussed herein.
[0076] Further, one or more embodiments of the invention may be
implemented using computer-executable instructions and/or data that
may be embodied on one or more non-transitory tangible
computer-readable mediums. The mediums may be, but are not limited
to, a hard disk, a compact disc, a digital versatile disc, a flash
memory card, a Programmable Read Only Memory (PROM), a Random
Access Memory (RAM), a Read Only Memory (ROM), Magnetoresistive
Random Access Memory (MRAM), a magnetic tape, or other
computer-readable media.
[0077] The control station can also form part of a network. The
network may transport data from a source to a destination.
Embodiments of suitable networks may use network devices, such as
routers, switches, firewalls, and/or servers (not shown) and
connections (e.g., links) to transport data. Data may refer to any
type of machine-readable information having substantially any
format that may be adapted for use in one or more networks and/or
with one or more devices (e.g., electronic device, service
provider, etc.). Data may include digital information or analog
information. Data may further be packetized and/or non-packetized.
The network may be a hardwired network using wired conductors
and/or optical fibers and/or may be a wireless network using
free-space optical, radio frequency (RF), and/or acoustic
transmission paths. In one implementation, the network may be a
substantially open public network, such as the Internet. In another
implementation, the network may be a more restricted network, such
as a corporate virtual network. The network may include Internet,
intranet, Local Area Network (LAN), Wide Area Network (WAN),
Metropolitan Area Network (MAN), wireless network (e.g., using IEEE
802.11), or other type of network.
[0078] The foregoing description may provide illustration and
description of various embodiments of the invention, but is not
intended to be exhaustive or to limit the invention to the precise
form disclosed. Modifications and variations may be possible in
light of the above teachings or may be acquired from practice of
the invention. For example, while a series of acts has been
described above, the order of the acts may be modified in other
implementations consistent with the principles of the invention. No
element, act, or instruction used in the description of the
invention should be construed critical or essential to the
invention unless explicitly described as such.
* * * * *