U.S. patent application number 15/974457 was filed with the patent office on 2018-09-13 for nanoimprint lithography.
The applicant listed for this patent is ELWHA, LLC. Invention is credited to Roderick A. Hyde, Jordin T. Kare, Thomas A. Weaver.
Application Number | 20180257269 15/974457 |
Document ID | / |
Family ID | 51016276 |
Filed Date | 2018-09-13 |
United States Patent
Application |
20180257269 |
Kind Code |
A1 |
Hyde; Roderick A. ; et
al. |
September 13, 2018 |
NANOIMPRINT LITHOGRAPHY
Abstract
A mold may include a plurality of nanostructures configured to
form a lithographic pattern when imprinted into a material.
Imprinting may include imprinting the mold a first predetermined
distance, modifying a temperature of the material, and altering a
position of the mold based on the temperature modification. One or
more thermal elements may alter a temperature of a first section of
the material and/or one or more nanostructures for a predetermined
pulse time less than an equilibrium time required for the mold
and/or material to reach a stable temperature state. A first
thermal element may selectively alter the temperature of a first
section of the material and/or a first nanostructure and a second
thermal element may selectively alter the temperature of a second
section of the material and/or a second nanostructure. The one or
more thermal elements may include one or more thermoelectric
elements.
Inventors: |
Hyde; Roderick A.; (Redmond,
WA) ; Kare; Jordin T.; (Seattle, WA) ; Weaver;
Thomas A.; (San Mateo, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ELWHA, LLC |
Bellevue |
WA |
US |
|
|
Family ID: |
51016276 |
Appl. No.: |
15/974457 |
Filed: |
May 8, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13733752 |
Jan 3, 2013 |
9962863 |
|
|
15974457 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 33/424 20130101;
B29C 2059/023 20130101; B29C 59/022 20130101; B29C 35/0888
20130101; B29C 2035/0844 20130101; B29C 2035/0827 20130101; B29C
2035/1616 20130101; G03F 7/0002 20130101 |
International
Class: |
B29C 33/42 20060101
B29C033/42; B29C 59/02 20060101 B29C059/02; G03F 7/00 20060101
G03F007/00 |
Claims
1. A method for nanoimprinting a lithographic pattern into a
material, the method comprising: altering a first temperature of a
first section of the material smaller than the whole material with
a first thermoelectric element; and imprinting a mold comprising a
plurality of nanostructures into the material to form the
lithographic pattern.
2. The method of claim 1, further comprising acquiring time
dependent measurements of a property of the material using a
sensor.
3. The method of claim 4, wherein altering the first temperature
comprises altering the first temperature based on the time
dependent measurements.
4. The method of claim 1, wherein altering the first temperature
comprises altering the first temperature with a first
thermoelectric element comprising a first semiconductor.
5. The method of claim 6, wherein altering the first temperature
comprises altering the first temperature with a first
thermoelectric element comprising a first doped semiconductor.
6. The method of claim 7, wherein altering the first temperature
comprises altering the first temperature with a first
thermoelectric element comprising a second doped semiconductor
comprising excess electrons, and wherein the first doped
semiconductor comprises excess electron holes.
7. The method of claim 8, wherein altering the first temperature
comprises altering the first temperature with a first
thermoelectric element further comprising: a first conductor
coupled to the first doped semiconductor and a selectively operable
power source; a second conductor coupled to the second doped
semiconductor and the selectively operable power source; and a
third conductor coupled to the first doped semiconductor and the
second doped semiconductor.
8. The method of claim 9, wherein altering the first temperature
comprises delivering power with a first polarity to heat the first
thermoelectric element and delivering power with a second polarity
to cool the first thermoelectric element.
9. The method of claim 1, wherein altering the first temperature
comprises altering the first temperature for a predetermined pulse
time.
10. The method of claim 9, further comprising an initial step of
selecting the predetermined pulse time based on a thermal
diffusivity of the material.
11. The method of claim 9, wherein altering the first temperature
comprises altering the first temperature of the first section a
plurality of times for a corresponding plurality of predetermined
pulse times.
12. The method of claim 9, wherein altering the first temperature
comprises delivering a sequence of thermal pulses, wherein each
thermal pulse delivers heat to or removes heat from the first
section, and wherein each thermal pulse lasts for a corresponding
predetermined pulse time.
13. The method of claim 9, further comprising selecting the
predetermined pulse time to create a predetermined spatial
temperature profile.
14. The method of claim 1, wherein altering the first temperature
comprises delivering a predetermined amount of heat to the first
section.
15. The method of claim 1, wherein altering the first temperature
comprises removing a predetermined amount of heat from the first
section.
16. The method of claim 1, further comprising altering a second
temperature of a second section of the material smaller than the
whole material with a second thermoelectric element.
17. The method of claim 16, wherein altering the first temperature
of the first section and altering the second temperature of the
second section comprise creating a predetermined spatial
temperature profile.
18. The method of claim 16, wherein altering the first temperature
of the first section comprises delivering heat to the first
section, and wherein altering a second temperature of a second
section comprises removing heat from the second section.
19. The method of claim 16, wherein altering the first temperature
of the first section comprises delivering a first predetermined
amount of heat to the first section, and wherein altering the
second temperature of the second section comprises delivering a
second predetermined amount of heat to the second section.
20. The method of claim 16, wherein the first temperature is
altered with a first thermoelectric element thermally insulated
from the second thermoelectric element.
21. A method for nanoimprinting a lithographic pattern into a
material, the method comprising: imprinting a mold comprising a
plurality of nanostructures into the material to form the
lithographic pattern; and altering a first temperature of a first
nanostructure using a first thermoelectric element.
22. The method of claim 21, wherein imprinting the mold comprises
imprinting the mold into a resist.
23. The method of claim 22, wherein imprinting the mold comprises
imprinting the mold into a mask.
24. The method of claim 22, wherein imprinting the mold comprises
imprinting the mold into a monomer.
25. The method of claim 22, wherein imprinting the mold comprises
imprinting the mold into a polymer.
26. The method of claim 25, wherein the polymer is a thermoplastic
polymer.
27. The method of claim 22, wherein imprinting the mold comprises
imprinting the mold into a liquid curable under ultraviolet
light.
28. The method of claim 21, wherein imprinting the mold comprises
imprinting the mold into a substrate.
29. The method of claim 28, wherein imprinting the mold comprises
imprinting the mold into silicon.
30. The method of claim 28, wherein imprinting the mold comprises
imprinting the mold into silicon dioxide.
31. The method of claim 28, wherein altering the first temperature
comprises modifying a chemical property of the substrate.
32. The method of claim 28, wherein altering the first temperature
comprises modifying a physical property of the substrate.
33. The method of claim 32, wherein modifying the physical property
comprises changing a viscosity of the substrate.
34. The method of claim 32, wherein modifying the physical property
comprises changing a strength of the substrate.
35. The method of claim 32, wherein modifying the physical property
comprises changing a phase of the substrate.
36. The method of claim 21, wherein imprinting the mold comprises
imprinting a pattern comprising at least one transistor
element.
37. The method of claim 21, wherein imprinting the mold comprises
imprinting a pattern comprising at least one element of an
information storage device.
38. The method of claim 21, wherein imprinting the mold comprises
imprinting a pattern comprising at least one element of a photonic
device.
39. The method of claim 21, wherein imprinting the mold comprises
imprinting a pattern comprising at least one component of an
electromechanical system.
Description
[0001] If an Application Data Sheet (ADS) has been filed on the
filing date of this application, it is incorporated by reference
herein. Any applications claimed on the ADS for priority under 35
U.S.C. .sctn..sctn. 119, 120, 121, or 365(c), and any and all
parent, grandparent, great-grandparent, etc. applications of such
applications, are also incorporated by reference, including any
priority claims made in those applications and any material
incorporated by reference, to the extent such subject matter is not
inconsistent herewith.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] The present application is related to and/or claims the
benefit of the earliest available effective filing date(s) from the
following listed application(s) (the "Priority Applications"), if
any, listed below (e.g., claims earliest available priority dates
for other than provisional patent applications or claims benefits
under 35 USC .sctn. 119(e) for provisional patent applications, for
any and all parent, grandparent, great-grandparent, etc.
applications of the Priority application(s)). In addition, the
present application is related to the "Related Applications," if
any, listed below.
PRIORITY APPLICATIONS
[0003] For purposes of the USPTO extra-statutory requirements, the
present application constitutes a continuation of Unites States
patent application Ser. No. 13/733,752 entitled NANOIMPRINT
LITHOGRAPHY, naming Roderick A. Hyde, Jordin T. Kare, and Thomas A.
Weaver as inventors, filed 3 Jan. 2013, which is currently
co-pending or is an application of which a currently co-pending
application is entitled to the benefit of the filing date.
[0004] The United States Patent Office (USPTO) has published a
notice to the effect that the USPTO's computer programs require
that patent applicants reference both a serial number and indicate
whether an application is a continuation, continuation-in-part, or
divisional of a parent application. Stephen G. Kunin, Benefit of
Prior-Filed Application, USPTO Official Gazette Mar. 18, 2003. The
USPTO further has provided forms for the Application Data Sheet
which allow automatic loading of bibliographic data but which
require identification of each application as a continuation,
continuation-in-part, or divisional of a parent application. The
present Applicant Entity (hereinafter "Applicant") has provided
above a specific reference to the application(s) from which
priority is being claimed as recited by statute. Applicant
understands that the statute is unambiguous in its specific
reference language and does not require either a serial number or
any characterization, such as "continuation" or
"continuation-in-part," for claiming priority to U.S. patent
applications. Notwithstanding the foregoing, Applicant understands
that the USPTO's computer programs have certain data entry
requirements, and hence Applicant has provided designation(s) of a
relationship between the present application and its parent
application(s) as set forth above and in any ADS filed in this
application, but expressly points out that such designation(s) are
not to be construed in any way as any type of commentary and/or
admission as to whether or not the present application contains any
new matter in addition to the matter of its parent
application(s).
[0005] If the listings of applications provided above are
inconsistent with the listings provided via an ADS, it is the
intent of the Applicant to claim priority to each application that
appears in the Priority Applications section of the ADS and to each
application that appears in the Priority Applications section of
this application.
[0006] All subject matter of the Priority Applications and the
Related Applications and of any and all parent, grandparent,
great-grandparent, etc. applications of the Priority Applications
and the Related Applications, including any priority claims, is
incorporated herein by reference to the extent such subject matter
is not inconsistent herewith.
TECHNICAL FIELD
[0007] This application relates to systems and methods for
nanoimprinting a lithographic pattern.
SUMMARY
[0008] A lithographic pattern may be formed on a material, such as
a resist, by imprinting a mold with a plurality of nanostructures
into the material. Imprinting may include imprinting the mold a
first predetermined distance, modifying a temperature of the
material after imprinting the first predetermined distance, and
adjusting a position of the mold after modifying the temperature of
the material. The mold may be withdrawn and any residual resist can
be removed. The desired processing can then be performed on the
exposed substrate.
[0009] A temperature of the mold and/or material may be modified
using temporally and/or spatially localized temperature control.
Temporally localized temperature control may include modifying a
temperature of one or more nanostructures and/or a section of the
mold and/or material for a predetermined pulse time. The
predetermined pulse time may be less than an equilibrium time
required for the mold and/or material to reach thermal equilibrium.
At thermal equilibrium, the mold and/or material may be in a stable
temperature state.
[0010] Spatially localized control may include using multiple
thermal elements to selectively modify the temperature of
corresponding nanostructures and/or sections of the mold and/or
material. The thermal elements may include one or more
thermoelectric elements. Thermoelectric elements may be configured
to deliver and/or remove heat based on the polarity of the voltage
applied to them. The thermoelectric elements may also be used to
deliver thermal pulses, such as delivering heat with a first
thermal pulse and removing heat with a second thermal pulse.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is cross-section view of steps in a method for
imprinting a lithographic pattern.
[0012] FIG. 2 is a cross-section view of a system for
nanoimprinting a lithographic pattern into a resist.
[0013] FIG. 3 is a top perspective view of a spatial temperature
profile that may be created by a nanoimprint system.
[0014] FIG. 4 is a cross-section view of a system and a spatial
temperature profile created in a resist by that system.
[0015] FIG. 5 is a graph of a temperature curve of the heating
elements as a function of time.
[0016] FIG. 6 is a cross-section view of a system for
nanoimprinting a lithographic pattern into a resist.
[0017] FIG. 7 is a schematic diagram of a system for nanoimprinting
a lithographic pattern into a resist.
[0018] FIG. 8 is a perspective view of a thermoelectric element
configured to deliver and/or remove heat from a material.
[0019] FIG. 9A is a schematic diagram of the operation of the
thermoelectric element when coupled to a selectively operable power
supply.
[0020] FIG. 9B is a schematic diagram of the operation of the
thermoelectric element when coupled to a selectively operable power
supply.
[0021] FIG. 10 is a cross-section view of a system for
nanoimprinting a lithographic pattern into a resist.
[0022] FIG. 11 is a cross-section view of the system and a spatial
temperature profile created in the resist by that system.
[0023] FIG. 12A is a cross-section view of arrangements of
thermoelectric elements within molds.
[0024] FIG. 12B is a cross-section view of arrangements of
thermoelectric elements within molds.
[0025] FIG. 13A is a graph of temperature curves for the
thermoelectric elements.
[0026] FIG. 13B is a graph of temperature curves for the
thermoelectric elements.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0027] Nanoimprint lithography includes various methods for
producing a lithographic pattern in a material. A mold may be
formed that produces the lithographic pattern when the mold is
imprinted into the material. The mold may include a plurality of
nanostructures that produce features with sizes on the order of
nanometers or smaller when imprinted into the material. For
example, the mold may be imprinted into a resist and/or mask. The
resist and/or mask may be a liquid, a solid above a glass
transition temperature, or the like. Once the mold has been
imprinted, the resist and/or mask may be cured with ultraviolet
(UV) light and/or cooled below the glass transition temperature.
After the mold is removed, a thin layer of residual resist and/or
mask material may remain where the pattern has been imprinted. This
residual resist and/or mask material may be removed by known
etching techniques. Deposition and/or etching may then be performed
on exposed portions of the substrate. The mold may be configured to
pattern one or more transistor elements, elements of an information
storage device, elements of a photonic device, components of an
electromechanical system, and/or the like. Multiple elements and/or
components may be combined to create a transistor, information
storage device, photonic device, electromechanical system, or the
like.
[0028] Imprinting the mold into the resist may include multiple
steps. The mold may be imprinted a first predetermined distance
into the material using an imprinting mechanism. During imprinting
and/or after the mold is imprinted the first predetermined
distance, a temperature of the material may be modified, such as
with a thermal element. For example, the thermal element may begin
modifying the temperature while the mold is being imprinted the
first distance. After the temperature has been modified, a position
of the mold may be adjusted based on the temperature modification.
In an embodiment, imprinting a first predetermined distance may
include touching the surface of the material with the mold (e.g.,
the first predetermined distance may be substantially zero). In
another embodiment, the first predetermined distance substantially
equals a material depth. In another embodiment, the first
predetermined distance corresponds to a modified temperature depth
(e.g., the depth of material that has had its temperature
modified).
[0029] Adjusting a position may include imprinting the mold a
second predetermined distance, rotating the mold and/or at least
one nanostructure to create an undercut in the material,
withdrawing the mold fully or partially from the material, and/or
the like. The second predetermined distance may correspond to the
modified temperature depth. The sum of the first predetermined
distance and the second predetermined distance may be less than the
first predetermined distance. The sum of the first predetermined
distance and the second predetermined distance may substantially
equal the material depth. The sum of the first predetermined
distance and the second predetermined distance may substantially
equal and/or correspond to the modified temperature depth.
Adjusting a position based on the temperature modification may
include adjusting the position based on a predicted spatial
temperature profile, based on a predicted spatial-temporal
temperature profile, based on measurements from a sensor, and/or
the like. The sensor measurements may be used to determine a
velocity and/or imprint force to use when adjusting the
position.
[0030] The temperature of the material may be further altered after
the position of the mold has been adjusted. The thermal element may
begin further altering the temperature during adjusting of the
position (e.g., while the mold is being imprinted the second
predetermined distance.) The thermal element may deliver heat when
initially modifying the temperature and remove heat during the
further alteration of the temperature. After the heat has been
removed, the mold may be withdrawn from the material. The thermal
element may be configured to deliver a first predetermined amount
of heat when initially modifying the temperature and deliver a
second predetermined amount of heat during the further alteration
of the temperature. A property of the material may be modified
during the initial temperature modification and/or during the
further alteration of the material.
[0031] Temperature control for nanoimprint lithography may be
localized spatially and/or temporally. In an embodiment, the
temperature of spatially localized areas of the material into which
the mold is being imprinted may be altered. For example, one or
more thermal elements may be configured to alter the temperature of
a section of the material smaller than the whole material.
Alternatively or in addition, the temperature of specific
nanostructures on the mold and/or a section of the mold smaller
than the whole mold may be altered by the one or more thermal
elements.
[0032] To achieve temporally localized temperature control, the
temperature of the material and/or mold, such as the temperature of
specific nanostructures and/or sections, may be altered for a
predetermined pulse time using the thermal element. Thermal
diffusion may result in the material and/or mold reaching thermal
equilibrium (i.e., a stable temperature state) if the pulse time is
long enough. Accordingly, the predetermined pulse time may be
selected to be less than an equilibrium time required for the
material and/or mold to reach thermal equilibrium. A spatial
temperature profile may be created in the section of the material
and/or mold based on the predetermined pulse time. A spatial
profile of material at a same temperature may be created based on
the predetermined pulse time. Accordingly, the pulse time may be
selected to create a predetermined spatial temperature profile in
the material and/or mold and/or to create a predetermined spatial
profile of material at an operative temperature.
[0033] The pulse time may be selected to be less than an imprint
time, selected based on a thermal diffusivity of the material
and/or mold, and/or the like. The thermal element may be configured
to alter the temperature of the material and/or mold a plurality of
times for a corresponding plurality of predetermined pulse times.
The thermal element may deliver a sequence of thermal pulses that
deliver heat to or remove heat from the material and/or mold with
each thermal pulse lasting for a corresponding predetermined pulse
time. For example, the thermal element may deliver heat for a
predetermined heating time and remove heat for a predetermined
cooling time. The thermal element may be configured to remove heat
during separation of the mold from the material. The thermal
element may be configured to deliver and/or remove a predetermined
amount of heat from the material and/or mold.
[0034] The thermal element may be positioned in a variety of
locations. The thermal element may be in direct contact with the
substrate, or the thermal element may be in one of the plurality of
nanostructures. The thermal element may be thermally coupled to one
or more of the plurality of nanostructures. The thermal element may
modify the temperature of the material by modifying a temperature
of one of the plurality of nanostructures. One or more of the
plurality of nanostructures may conduct thermal energy between the
thermal element and the section of the material and/or mold. When
the thermal element is configured to alter the temperature of a
section of the material, one or more nanostructures may be
configured to imprint in that section and/or within a predetermined
diffusion distance of that section.
[0035] Multiple sections of the material and/or mold may have their
temperature altered by thermal elements. For example, a first
thermal element may alter a first temperature of a first
nanostructure and/or a first section of the material and/or mold,
and a second thermal element may alter a second temperature of a
second nanostructure and/or a second section of the material and/or
mold. The thermal elements may be configured and/or positioned to
create a predetermined spatial temperature profile in the material
and/or mold and/or a predetermined spatial profile of material at
an operative temperature. Under one configuration, the first
thermal element may deliver heat to the first section and/or
nanostructure, and the second thermal element may remove heat from
the second section and/or nanostructure. In another configuration,
the first thermal element may deliver a first predetermined amount
of heat to the first section and/or nanostructure, and the second
thermal element may deliver a second predetermined amount of heat
to the second section and/or nanostructure.
[0036] Various thermal elements may be used to alter the
temperature of the material and/or mold. A photoirradiation unit
may include one or more thermal elements. The photoirradiation unit
may be configured to generate a first pixel of radiation on the
first section of the material and/or mold and a second pixel of
radiation on the second section of the material and/or mold. The
mold may include a first portion with a first transparency and a
second portion with a second transparency to generate the first and
second pixels. A cooling element may cool the material and/or mold
while the first and second pixels are generated on the material
and/or mold. The mold may be substantially and/or entirely
transparent to radiation from the photoirradiation unit.
[0037] The thermal element may include a heating element, such as a
resistive heating element, a photoheating element, and/or the like.
The photoheating element may be configured to emit UV light,
x-rays, and/or the like. The mold may be substantially or entirely
transparent to the radiation from the photoheating element. A
cooling element may be configured to cool the material and/or mold
while the heating element heats the first nanostructure and/or the
first section of the material and/or mold. The thermal element may
include a cooling element. The cooling element may include a
thermally conductive fluid, such as water. The cooling element may
include a heat sink. The heat sink may be configured to change
phase, such as by melting and/or vaporizing. A heating element may
be configured to heat the material and/or mold while the cooling
element removes heat from the first nanostructure and/or the first
section of the material and/or mold. Heating elements and cooling
elements may be separated from one another by thermal
insulation.
[0038] The thermal element may include a thermoelectric element. A
thermoelectric element may be configured to deliver heat to the
first nanostructure and/or the first section when a voltage with a
first polarity is applied and may be configured to remove heat from
the first nanostructure and/or the first section when a voltage
with a second polarity is applied. The thermoelectric element may
heat the first nanostructure and/or the first section for a first
time period and cool the first nanostructure and/or the first
section for a second time period. The thermoelectric element and a
heating and/or cooling element may be configured to alter the
temperature of the material and/or mold. The thermoelectric element
may be configured to alter a first temperature of the first
nanostructure and/or the first section of the material and/or mold
and the heating and/or cooling element may be configured to alter a
temperature of the remainder of the material and/or mold and/or the
other of the material and the mold. A first thermoelectric element
may be configured to alter the first temperature of the first
nanostructure and/or the first section, and a second thermoelectric
element may be configured to alter a material temperature of the
material and/or a second temperature of the second nanostructure
and/or the second section. Thermoelectric elements may be separated
from each other, from heating elements, and/or from cooling
elements by thermal insulation.
[0039] The thermoelectric element may be made from doped
semiconductors. A first doped semiconductor may include excess
electron holes, and a second doped semiconductor may include excess
electrons. First and second conductors may couple the first and
second doped semiconductors respectively to a selectively operable
power source. The selectively operable power source may be
configured to selectively apply the first or second polarity to the
thermoelectric element depending on whether heat should be
delivered or removed. A third conductor may couple the first doped
semiconductor to the second doped semiconductor. The first and
second conductors and/or the third conductor may be configured to
deliver and remove the heat from the material and/or mold.
[0040] One or more sensors may be configured to acquire time
dependent measurements of properties of the material and/or mold.
Sensors may measure the temperature of the material and/or mold, an
optical property of the material and/or mold, an electrical
property of the material and/or mold, and/or the like. The
predetermined pulse time may be selected based on the time
dependent measurements. The first and/or second thermal element may
be configured to selectively alter the first and/or second
temperature based on feedback from the sensor and/or based on the
time dependent measurements. When to start and/or stop imprinting
and/or removing the mold may be determined based on the time
dependent measurements.
[0041] When imprinting the mold into the material, the imprint
depth may equal the depth of the material. Alternatively, the
imprint depth may substantially equal the depth of the material.
For example, the imprint depth may be selected to leave a thin
layer of material where the pattern has been imprinted. To create a
desired spatial temperature profile, the material may include a
first substance with a first thermal diffusivity and a second
substance with a second thermal diffusivity. A single thermal
element may alter the temperature of the first and second
substances, and/or each substance may have a corresponding thermal
element configured to alter a temperature of that substance. A
first of the plurality of nanostructures may be configured to
imprint in the first substance, and a second of the plurality of
nanostructures may be configured to imprint in the second
substance.
[0042] The mold may imprint into various materials. The mold may
imprint into a resist. The resist may include a mask, a monomer, a
polymer, such as a thermoplastic polymer, a liquid curable under UV
light, and/or the like. The mold may imprint into the substrate.
The substrate may include silicon, silicon dioxide, and/or the
like. The thermal element may be configured to modify a property of
the substrate. The thermal element may modify a chemical property,
such as by causing decomposition of a substrate element, by causing
a reaction between two elements on the substrate, by crosslinking
two elements on the substrate, and/or the like. The thermal element
may modify a physical property, such as by changing a viscosity of
the substrate, changing a strength of the substrate, changing a
phase of the substrate, and/or the like.
[0043] FIG. 1 is cross-section view of steps 102, 103, 104, 106,
108 in a method 100 for imprinting a lithographic pattern. First, a
mold 110 including a plurality of nanostructures 112 configured to
create the lithographic pattern and a substrate 120 with a layer of
resist 130 may be provided 102. The resist 130 may be an UV curable
liquid and/or a material above its glass-transition temperature.
The resist 130 may be heated above its glass-transition temperature
during step 102. The mold 110 may be attached to an imprinting
mechanism 115. The imprinting mechanism 115 may imprint 103 the
mold 110 a first predetermined distance into the resist 130. After
or during imprinting 103, the resist 130 may be further heated
and/or cooled. In some embodiments, step 103 may be omitted.
[0044] The imprinting mechanism 115 may imprint 104 the mold 110 a
second predetermined distance into the resist 130. After or during
imprinting 104 the second predetermined distance, the resist 130
may be UV cured and/or cooled below its glass-transition
temperature. Alternatively or in addition, the temperature of the
resist 130 and/or the substrate 120 may be altered to modify a
chemical and/or physical property of the resist 130 and/or the
substrate 120. Next, the mold 110 may be removed 106 from the
resist 130. A thin layer of resist 132 may remain where the pattern
was imprinted. Etching 108 may remove the thin layer of resist 132
leaving the substrate 120 exposed for the desired processing.
[0045] FIG. 2 is a cross-section view of a system 200 for
nanoimprinting a lithographic pattern into a resist 230. A mold 210
may include a plurality of nanostructures 212 and a plurality of
heating elements 214 configured to heat the plurality of
nanostructures 212. The plurality of heating elements 214 may
include a plurality of resistive heating elements. A cooling
element 240 may be in thermal contact with a substrate 220. The
cooling element 240 may include a plurality of ports 242 to
circulate thermally conductive fluid 244 and thereby to remove heat
from the substrate 220. The thermally conductive fluid 244 may be
circulated to a heat sink (not shown) or the like to remove excess
heat from the thermally conductive fluid 244. A plurality of
temperature sensors 250 may detect the temperature of the resist
230. The positions of the heating elements 214 and cooling element
240 as well as the amount of heat delivered and removed by those
elements may be selected to create a predetermined spatial
temperature profile in the resist 230.
[0046] FIG. 3 is a top perspective view of a spatial temperature
profile 300 that may be created by a nanoimprint system similar to
the nanoimprint system 200. The spatial temperature profile may
include a plurality of regions 310, 312, 314, 316, 318, 320, each
at a same temperature. The region 310 in contact with the
nanostructures 212 may be at a hottest temperature and therefore
most deformable. The region 320 furthest from the nanostructures
212 may be at a coldest temperature and therefore least deformable.
Accordingly, the mold 210 may leave a pattern in the region 310 in
contact with the nanostructures 212 without unduly damaging and/or
deforming the region 320 furthest from the nanostructures 212.
[0047] FIG. 4 is a cross-section view of a system 400 and a spatial
temperature profile 460 created in a resist 430 by that system 400.
The spatial temperature profile 460 includes a plurality of regions
462, 464, 466, 488, 470, each at a same temperature. A mold 410 may
include heated nanostructures 412 that conduct heat to the resist
430. A hottest region 462 may be in contact with the nanostructures
412. A cooling element 440 may remove heat from a substrate 420.
Thus, a coolest region 470 may be in contact with the substrate
420. In one embodiment, the heat may be delivered via the
nanostructures 412 at the same time that heat is removed by the
cooling element 440. For example, the heat delivered through the
nanostructures 412 may increase the deformability of nearby resist,
while the cooling element 440 increases structural stability of
resist in gaps between the nanostructures 412. Alternatively or in
addition, the cooling element 440 may cool the resist 430 below its
glass-transition temperature after heat is no longer being
delivered, so the mold 410 can be withdrawn.
[0048] FIG. 5 is a graph 500 of a temperature curve 510 of the
heating elements 214 as a function of time. The graph 500 has a
temperature axis 512 and a time axis 514. During an insertion time
520, the heating elements 214 may deliver a first predetermined
amount of heat to the resist 230. For example, the heating elements
214 may activate for a predetermined pulse time, which may be
longer than the insertion time 520. The first predetermined amount
of heat may be selected to soften the resist 230 sufficiently for
the mold 210 to imprint in the resist 230. After insertion, the
heating elements 214 may cease delivering heat, and the resist 230
may be cooled and hardened by the cooling element 240. Once the
resist 230 has hardened, the heating elements 214 may deliver a
second predetermined amount of heat during a removal time 530. The
second predetermined amount of heat may be selected to soften the
resist 230 sufficiently for the mold 210 to be separated from the
resist 230 without causing damage to the lithographic pattern. The
second predetermined amount of heat may be selected not to soften
the resist 230 so much as to dissolve the lithographic pattern.
[0049] FIG. 6 is a cross-section view of a system 600 for
nanoimprinting a lithographic pattern into a resist 630. A mold 610
may include a plurality of nanostructures 612 configured to imprint
in a first area 631 and a second area 632 of the resist 630 while
not imprinting in third area 633. A heating and cooling mechanism
640 may be in contact with a substrate 620. The heating and cooling
mechanism may include resistive heating elements 642 configured to
deliver heat to the first and second areas 631, 632 and a cooling
element 644 configured to remove heat from the third area 633. As a
result, the first and second areas 631, 632 may be above the
glass-transition temperature to allow for imprinting while the
third area 633 may be below the glass-transition temperature to
prevent undesirable deformation. The heating and cooling elements
642, 644 may be thermally insulated from each other by insulation
645. The mold 610 may include a plurality of sensors 650. The
plurality of sensors 650 may be configured to indirectly measure
temperatures of the first, second, and third areas 631, 632, 633.
The heating and cooling mechanism 640 may be configured to adjust
the amount of heat delivered and/or removed based on feedback from
the sensors 650.
[0050] FIG. 7 is a schematic diagram of a system 700 for
nanoimprinting a lithographic pattern into a resist 730. The system
700 may include a photoirradiation unit 714 configured to heat the
resist 730 by delivering electromagnetic radiation, such as UV
light, x-rays, and/or the like, to the resist 730. Alternatively or
in addition, the resist 730 may be a UV curable liquid. A mold 710
imprinting into the resist 730 may include first regions 715 with a
first transparency and second regions 716 with a second
transparency. The first and second regions 715, 716 may thus allow
different amounts of heat to be delivered to different sections of
the resist 730. In the illustrated embodiment, the first region 715
may include a plurality of nanostructures 712 and may be configured
to allow through most or all of the radiation. The second region
716 may include the gaps between the nanostructures 712 and may be
configured to block most or all of the radiation. Thus, resist near
the nanostructures 712 may be above the glass-transition
temperature and easily deformable while resist near the gaps may be
below the glass-transition temperature and not easily deformable.
In other embodiments, such as when the resist 730 is UV curable,
the first region 715 may block most or all radiation while the
second region 716 allows through most or all radiation. In other
embodiments, the system may contain multiple, independently
operable photoirradiation units. In some embodiments, local
photoirradiation units (e.g., LEDs, quantum dots, plasmonic
resonators, or the like) may be incorporated into the
nanostructures.
[0051] FIG. 8 is a perspective view of a thermoelectric element 800
configured to deliver and/or remove heat from a material (not
shown). The thermoelectric element 800 may include one or more
doped semiconductors. A first semiconductor 810 may include p-type
doping (i.e., may include excess electron holes), and a second
semiconductor 820 may include n-type doping (i.e., may include
excess electrons). A first conductor 830 may be directly coupled to
the first semiconductor 810, a second conductor 840 may be directly
coupled to the second semiconductor 820, and a third conductor 850
may be directly coupled to the first and second semiconductors 810,
820. The first and second conductors 830, 840 may be directly
coupled and/or wired to a power supply 860.
[0052] FIGS. 9A,B are schematic diagrams of the operation of the
thermoelectric element 800 when coupled to a selectively operable
power supply 960. The selectively operable power supply 960 may
apply a voltage with a first polarity 961 to pump heat to the third
conductor 850 from the first and second conductors 830, 840 and
apply a voltage with a second polarity 962 to pump heat from the
third conductor 850 to the first and second conductors 830, 840.
Thus, the third conductor 850 and/or the first and second
conductors 830, 840 may be able to remove and deliver heat to a
material based on the polarity applied by the selectively operable
power supply 960.
[0053] FIG. 10 is a cross-section view of a system 1000 for
nanoimprinting a lithographic pattern into a resist 1030. A mold
1010 may include a plurality of nanostructures 1012 and mold
thermoelectric elements 1014 configured to alter a temperature of
the mold 1010 and/or nanostructures 1012. The resist 1030 may be
atop a substrate 1020, and a substrate thermoelectric element 1040
may be configured to alter a temperature of the substrate 1020. The
thermoelectric elements 1014, 1040 may be configured to deliver
heat and/or remove heat from the mold 1010 and substrate 1020. When
the resist 1030 is in thermal contact with the mold 1010 and/or
substrate 1020, a temperature of the resist 1030 may be modified by
the thermoelectric elements 1014, 1040 as well.
[0054] FIG. 11 is a cross-section view of the system 1000 and a
spatial temperature profile 1160 created in the resist 1030 by that
system 1000. The mold thermoelectric elements 1014 may be
configured to deliver heat to the resist 1030 while the substrate
thermoelectric element 1040 removes heat from the resist 1030. The
mold thermoelectric elements 1014 may be positioned near the
nanostructures 1012 while the substrate thermoelectric element 1040
may be positioned near an area of the resist 1030 where the
nanostructures 1012 are not imprinted. Under such a configuration,
the mold thermoelectric elements 1014 may heat a section of the
resist 1030 so that it may be deformed by the nanostructures 1012
while the substrate thermoelectric element 1040 cools and maintains
the structural stability of the area of the resist 1030 where the
nanostructures 1012 are not imprinted. A plurality of regions 1162,
1164, 1166, 1168, 1170, 1172, each at a same temperature, may
result with the hottest region 1162 nearest the mold thermoelectric
elements 1014 and the coldest region 1172 nearest the substrate
thermoelectric element 1040. Alternatively or in addition, one or
more of the thermoelectric elements 1014, 1040 may deliver heat to
the resist 1030 during a first time period and remove heat from the
resist 1030 during a second time period.
[0055] FIGS. 12A,B are cross-section views of arrangements of
thermoelectric elements 1214a,b, 1215a,b within molds 1210a,b. A
first mold 1210a may include nanostructures 1212a, 1213a with
different heights. Accordingly, a first thermoelectric element
1214a may alter the temperature of a longer nanostructure 1212a,
and a second thermoelectric element 1215a may alter the temperature
of a shorter nanostructure 1213a. A control unit 1260a may be
configured to selectively alter the temperature of the
thermoelectric elements 1214a, 1215a by determining a magnitude and
polarity of a voltage delivered to each thermoelectric element
1214a, 1215b. Similarly, a second mold 1210b may include a
nanostructure 1212b and a gap 1213b without a nanostructure. A
first thermoelectric element 1214b may alter the temperature of the
nanostructure 1212b, and a second thermoelectric element 1215b may
alter the temperature of the gap 1213b. A control unit 1260b may be
configured to select a polarity and magnitude of a voltage
delivered to each thermoelectric element 1214b, 1215b.
[0056] FIGS. 13A,B are graphs 1300a,b of temperature curves
1310a,b, 1311a,b for the thermoelectric elements 1214a,b, 1215a,b.
The graphs 1300a,b include temperature 1312a,b and time 1314a,b
axes. Temperature curve 1310a may be a temperature curve for the
first thermoelectric element 1214a during imprinting of the mold
1210a, and temperature curve 1311a may be a temperature curve for
the second thermoelectric element 1215a. Prior to an insertion time
1320a, the temperature of the first thermoelectric element 1214a
may begin increasing rapidly and significantly. The temperature of
the second thermoelectric element 1215a may not begin increasing
until after insertion and may increase less rapidly and less
significantly. At the end of the insertion time 1320a, the
temperature of the thermoelectric elements 1214a, 1215a may
decrease until the thermoelectric elements 1214a, 1215a are
removing heat from the nanostructures 1212a, 1213a. During a
removal time 1330a, the thermoelectric elements 1214a, 1215a may
remain at the cooler temperature.
[0057] Temperature curve 1310b may be a temperature curve for the
first thermoelectric element 1214b during imprinting of the mold
1210b, and temperature curve 1311b may be a temperature curve for
the second thermoelectric element 1215b. Prior to an insertion time
1320b, the first thermoelectric element 1214b may begin heating the
nanostructure 1212b, and the second thermoelectric element 1215b
may begin cooling the gap 1213b. At the end of the insertion time
1320b, the first thermoelectric element 1214b may begin cooling the
nanostructure 1212b, and the second thermoelectric element 1215b
may be allowed to return to thermal equilibrium. During a removal
time 1330b, the first thermoelectric element 1214b may continue to
cool the nanostructure 1212b, and the second thermoelectric element
1215b may continue to return to thermal equilibrium.
[0058] It will be understood by those having skill in the art that
many changes may be made to the details of the above-described
embodiments without departing from the underlying principles of the
disclosure. The scope of the present disclosure should, therefore,
be determined only by the following claims.
* * * * *