U.S. patent application number 14/649735 was filed with the patent office on 2015-10-22 for resin for nanoimprinting, laminate containing resin for nanoimprinting, printed board containing resin for nanoimprinting, and method for producing nanoimprint substrate.
This patent application is currently assigned to Japan Science and Technology Agency. The applicant listed for this patent is JAPAN SCIENCE AND TECHNOLOGY AGENCY. Invention is credited to Yuta SAITO, Hiroshi YABU.
Application Number | 20150298387 14/649735 |
Document ID | / |
Family ID | 50883242 |
Filed Date | 2015-10-22 |
United States Patent
Application |
20150298387 |
Kind Code |
A1 |
YABU; Hiroshi ; et
al. |
October 22, 2015 |
RESIN FOR NANOIMPRINTING, LAMINATE CONTAINING RESIN FOR
NANOIMPRINTING, PRINTED BOARD CONTAINING RESIN FOR NANOIMPRINTING,
AND METHOD FOR PRODUCING NANOIMPRINT SUBSTRATE
Abstract
Provided is a resin for nanoimprinting, which is capable of
preventing removal of a transfer-receiving resin from a substrate
when a mold is separated during nanoimprinting, and which is also
capable of transferring a pattern on a mold to a transfer-receiving
resin with high accuracy during thermal nanoimprinting, while
improving the throughput. A resin for nanoimprinting, which is
represented by formula (1). ##STR00001## (In the formula, each of
R.sub.1-R.sub.5 independently represents --H or --OH, and at least
one of the R.sub.1-R.sub.5 moieties represents --OH; R.sub.6
represents a linear, branched or cyclic alkyl group having 1-20
carbon atoms, an aryl group having 6-20 carbon atoms or an aralkyl
group having 7-20 carbon atoms; X represents an amide or an ester;
Y may be absent, or represents an amide or an ester; P represents
an integer of 1-10; and each of m and n represents an integer of 1
or more.)
Inventors: |
YABU; Hiroshi; (Sendai-shi,
Miyagi, JP) ; SAITO; Yuta; (Sendai-shi, Miyagi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
JAPAN SCIENCE AND TECHNOLOGY AGENCY |
Saitama |
|
JP |
|
|
Assignee: |
Japan Science and Technology
Agency
Kawaguchi-shi, Saitama
JP
|
Family ID: |
50883242 |
Appl. No.: |
14/649735 |
Filed: |
November 13, 2013 |
PCT Filed: |
November 13, 2013 |
PCT NO: |
PCT/JP2013/080635 |
371 Date: |
June 4, 2015 |
Current U.S.
Class: |
264/293 ;
526/304 |
Current CPC
Class: |
B29C 59/022 20130101;
C08F 220/54 20130101; B29C 59/005 20130101; C08F 220/70 20130101;
B32B 27/00 20130101; B29C 2059/023 20130101; B29K 2033/00 20130101;
G03F 7/0002 20130101; B29K 2105/24 20130101; B29K 2105/0005
20130101; C09D 133/24 20130101; C08F 220/54 20130101; C08F 220/58
20130101 |
International
Class: |
B29C 59/00 20060101
B29C059/00; B29C 59/02 20060101 B29C059/02; C08F 220/70 20060101
C08F220/70 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 5, 2012 |
JP |
2012-266628 |
Claims
1. A nanoimprinting resin represented by formula (1) below.
##STR00008## (In the formula, each of R.sub.1-R.sub.5 independently
represents --H or --OH, at least one of R.sub.1-R.sub.5
representing --OH. R.sub.6 represents a C.sub.1-20 linear,
branched, or cyclic alkyl group, a C.sub.6-20 aryl group, or a
C.sub.7-20 aralkyl group. X represents an amide or an ester. Y
represents an amide or an ester, or may be absent. P represents an
integer from 1 to 10. m and n are integers equal to or greater than
1.)
2. The nanoimprinting resin of claim 1, wherein m and n have a
ratio such that m:n=1:99-90:10.
3. The nanoimprinting resin of claim 1, wherein two of the
R.sub.1-R.sub.5 represent --OH.
4. The nanoimprinting resin of claim 1, wherein the nanoimprinting
resin is used between a substrate and a transfer-receiving resin to
which a mold is to be transferred.
5. A laminate comprising the nanoimprinting resin of claim 1.
6. A substrate comprising the nanoimprinting resin of claim 1.
7. A method for manufacturing a nanoimprinting substrate,
comprising: a step for laminating the nanoimprinting resin
represented by formula (1) below onto a substrate: ##STR00009## (in
the formula, each of R.sub.1-R.sub.5 independently represents --H
or --OH, at least one of R.sub.1-R.sub.5 representing --OH, R.sub.6
represents a C.sub.1-20 linear, branched, or cyclic alkyl group, a
C.sub.6-20 aryl group, or a C.sub.7-20 aralkyl group, X represents
an amide or an ester, Y represents an amide or an ester, or may be
absent, P represents an integer from 1 to 10, m and n are integers
equal to or greater than 1); a step for laminating a layer to which
a pattern from a mold is to be transferred on a layer of the
nanoimprinting resin; and a step for transferring the pattern from
the mold.
8. The method for manufacturing a nanoimprinting substrate of claim
7, wherein: the layer to which the pattern from the mold is to be
transferred is a thermoplastic resin, the steps for transferring
the pattern from the mold comprising: a step for heating the
substrate on which the thermoplastic resin is laminated to a
temperature higher than the glass transition temperature of the
thermoplastic resin; a step for pressing the mold; a step for
cooling the substrate to a temperature lower than the glass
transition temperature of the thermoplastic resin; and a step for
detaching the mold.
9. The method for manufacturing a nanoimprinting substrate of claim
7, wherein: the layer to which the pattern from the mold is to be
transferred is a thermosetting resin, the steps for transferring
the pattern from the mold comprising: a step for pressing the mold
at a temperature lower than the glass transition temperature of the
thermosetting resin; a step for heating the substrate on which the
thermosetting resin is laminated to a temperature higher than the
glass transition temperature of the thermosetting resin; and a step
for detaching the mold.
10. The method for manufacturing a nanoimprinting substrate of
claim 7, wherein: the layer to which the pattern from the mold is
to be transferred is formed by a solution containing a
polymerizable monomer and a photopolymerization initiator, the
steps for transferring the pattern from the mold comprising: a step
for pressing the mold; a step for cross-linking/curing the
polymerizable monomer; and a step for detaching the mold.
11. The method for manufacturing a nanoimprinting substrate of
claim 7, wherein m and n of the nanoimprinting resin have a ratio
such that m:n=1:99-90:10.
12. The method for manufacturing a nanoimprinting substrate of
claim 7, wherein two of the R.sub.1-R.sub.5 of the nanoimprinting
resin represent --OH.
Description
TECHNICAL FIELD
[0001] The present invention relates to a nanoimprinting resin, a
laminate including said resin, a printed substrate containing said
resin, and a method for manufacturing a nanoimprinted substrate,
and particularly relates to: a nanoimprinting resin provided
between a nanoimprinting substrate and a transfer-receiving resin
layer to which a mold (pattern) is transferred, whereby the
transfer-receiving resin layer is prevented from detaching when the
mold is to be transferred and detached; a laminate including said
resin; a printed substrate containing said resin; and a method for
manufacturing a nanoimprinted substrate.
TECHNICAL BACKGROUND
[0002] As information technology has advanced in recent years,
demand has increased for high-speed operation, low-power-consuming
operation, the functional integration known as "system LSI," and
other advanced technologies brought about by further
miniaturization of semiconductor devices. Continued miniaturization
of lithographic technology, which is the core technology behind
semiconductor devices, presents problems in that the initial cost
of lithography devices increases exponentially, and the price of
masks for obtaining the same degree of resolution as that of the
light wavelength used also rises.
[0003] Nanoimprint lithography, proposed by Chou et al. of
Princeton University in 1995, has drawn attention as a processing
technique having a resolution of 10 nm while being inexpensive.
Nanoimprinting is a technique in which a mold is pressed on a
transfer-receiving resin layer provided on a substrate, and a
nanometer-order pattern formed on the mold is transferred to the
transfer-receiving resin layer; fine patterns can be formed using
this technique at a lower cost than with existing lithography
techniques, making this technique applicable to semiconductor
devices and other electronic devices, optical devices, recording
media, chemical/biological devices, MEMS, and other industrial
machines.
[0004] Thermal nanoimprinting and optical nanoimprinting common
methods for nanoimprinting; these methods are differentiated by the
properties of the transfer-receiving resin. Of these methods,
thermal nanoimprinting comprises applying polymethylmethacrylate
(PMMA) or another thermoplastic resin to a substrate as a
transfer-receiving resin, heating the transfer-receiving resin to
or above the glass transition temperature thereof (105.degree. C.
for PMMA) and pressing a mold thereagainst, and removing the mold
and the substrate after cooling same, whereby a pattern on the mold
is transferred to the transfer-receiving resin.
[0005] However, in addition to the problem of shared
nanoimprinting, in which, when (3) a mold 3 is detached after (2)
being pressed against (1) a transfer-receiving resin 2 applied to a
substrate 1 as shown in FIG. 1, the transfer-receiving resin 2
detaches together with the mold 3, thermal nanoimprinting presents
other problems in that heating and cooling the transfer-receiving
resin takes time, reducing throughput.
[0006] Applying the transfer-receiving resin to a glass substrate
after treating the substrate with a silane coupling agent (see
non-patent reference 1), and causing a benzophenone derivative
containing a thiol to react with a gold coating on a substrate
before forming a polystyrene resin layer as a transfer-receiving
resin (see non-patent reference 2), are known as methods for
overcoming the problems described above. However, the method
described in non-patent reference 1 presents problems in that the
material of the substrate is limited to glass due to the silane
coupling agent treatment, and the method described in non-patent
reference 2 presents problems in that the gold coating is necessary
and the combination of substrate and transfer-receiving resin is
limited.
PRIOR ARTS LIST
Non-Patent References
[0007] Non Patent Document 1: Dae-Geun Choi et al., "Measurement of
Surface Adhesion Force of Adhesion Promoter and Release Layer for
UV-Nanoimprint Lithography", Journal of Nanoscience and
Nanotechnology, Vol. 9, p 769-773, 2009
[0008] Non Patent Document 2: Hirokazu Oda et al., "Photoreactive
Chemisorbed Monolayer Suppressing Polymer Dewetting in Thermal
Nanoimprint Lithography", Langmuir, 2009, 25(12), p 6604-6606
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0009] The present invention was designed to overcome the problems
described above. After thoroughgoing investigations, it was newly
discovered that by laminating a nanoimprinting resin represented by
formula (1) below onto a substrate and then laminating a
transfer-receiving resin for transferring a mold to the
nanoimprinting resin, it is possible to improve the adhesiveness
between the substrate and the transfer-receiving resin; prevent the
transfer-receiving resin from detaching from the substrate when the
mold is detached, irrespective of the type of substrate and
transfer-receiving resin; and improve throughput and accurately
transfer a pattern from the mold to the transfer-receiving resin
because the transfer-receiving resin does not detach from the
substrate even under high temperatures when the mold is detached.
This is because the transfer-receiving resin firmly adheres to the
substrate when thermal nanoimprinting is performed using a
thermoplastic resin as the transfer-receiving resin.
##STR00002##
[0010] (In the formula, each of R.sub.1-R.sub.5 independently
represents --H or --OH, at least one of R.sub.1-R.sub.5
representing --OH. R.sub.6 represents a C.sub.1-20 linear,
branched, or cyclic alkyl group, a C.sub.6-20 aryl group, or a
C.sub.7-20 aralkyl group. X represents an amide or an ester. Y
represents an amide or an ester, or may be absent. P represents an
integer from 1 to 10. m and n are integers equal to or greater than
1.)
[0011] Specifically, an object of the present invention is to
provide a nanoimprinting resin, a laminate including said resin, a
printed substrate containing said resin, and a method for
manufacturing a nanoimprinted substrate.
Means to Solve the Problems
[0012] The present invention is a nanoimprinting resin, a laminate
including said resin, a printed substrate containing said resin,
and a method for manufacturing a nanoimprinted substrate, described
below.
[0013] (1) A nanoimprinting resin represented by formula (1)
below.
##STR00003##
[0014] (In the formula, each of R.sub.1-R.sub.5 independently
represents --H or --OH, at least one of R.sub.1-R.sub.5
representing --OH. R.sub.6 represents a C.sub.1-20 linear,
branched, or cyclic alkyl group, a C.sub.6-20 aryl group, or a
C.sub.7-20 aralkyl group. X represents an amide or an ester. Y
represents an amide or an ester, or may be absent. P represents an
integer from 1 to 10. m and n are integers equal to or greater than
1.)
[0015] (2) The nanoimprinting resin of (1), wherein m and n have a
ratio such that m:n=1:99-90:10.
[0016] (3) The nanoimprinting resin of (1) or (2), wherein two of
the R.sub.1-R.sub.5 represent --OH.
[0017] (4) The nanoimprinting resin of any of (1)-(3), wherein the
nanoimprinting resin is used between a substrate and a
transfer-receiving resin to which a mold is to be transferred.
[0018] (5) A laminate comprising the nanoimprinting resin of any of
(1)-(4).
[0019] (6) A substrate comprising the nanoimprinting resin of any
of (1)-(4).
[0020] (7) A method for manufacturing a nanoimprinting substrate,
comprising:
[0021] a step for laminating the nanoimprinting resin of any of
(1)-(3) onto a substrate;
[0022] a step for laminating a layer to which a pattern from a mold
is to be transferred on a layer of the nanoimprinting resin;
and
[0023] a step for transferring the pattern from the mold.
[0024] (8) The method for manufacturing a nanoimprinting substrate
of (7), wherein:
[0025] the layer to which the pattern from the mold is to be
transferred is a thermoplastic resin, the steps for transferring
the pattern from the mold comprising:
[0026] a step for heating the substrate on which the thermoplastic
resin is laminated to a temperature higher than the glass
transition temperature of the thermoplastic resin;
[0027] a step for pressing the mold;
[0028] a step for cooling the substrate to a temperature lower than
the glass transition temperature of the thermoplastic resin;
and
[0029] a step for detaching the mold.
[0030] (9) The method for manufacturing a nanoimprinting substrate
of (7), wherein:
[0031] the layer to which the pattern from the mold is to be
transferred is a thermosetting resin, the steps for transferring
the pattern from the mold comprising:
[0032] a step for pressing the mold at a temperature lower than the
glass transition temperature of the thermosetting resin;
[0033] a step for heating the substrate on which the thermosetting
resin is laminated to a temperature higher than the glass
transition temperature of the thermosetting resin; and
[0034] a step for detaching the mold.
[0035] (10) The method for manufacturing a nanoimprinting substrate
of (7), wherein:
[0036] the layer to which the pattern from the mold is to be
transferred is formed by a solution containing a polymerizable
monomer and a photopolymerization initiator, the steps for
transferring the pattern from the mold comprising:
[0037] a step for pressing the mold;
[0038] a step for cross-linking/curing the polymerizable monomer;
and
[0039] a step for detaching the mold.
Advantageous Effects of the Invention
[0040] A layer of the nanoimprinting resin of the present invention
is provided between a substrate and a transfer-receiving resin for
transferring a pattern from a mold and nanoimprinted, whereby the
transfer-receiving resin can be prevented from detaching from the
substrate when the mold is detached, irrespective of the type of
substrate and transfer-receiving resin.
[0041] Additionally, using the nanoimprinting resin of the present
invention makes it possible to improve the throughput of thermal
nanoimprinting because it is possible to accurately transfer a
pattern from the mold to the transfer-receiving resin when the mold
is detached, even under high temperatures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 is a schematic view of a conventional nanoimprinting
procedure;
[0043] FIG. 2 is a schematic view of the nanoimprinting procedure
of the present invention;
[0044] FIG. 3 is a drawing-substitute photograph, specifically an
AFM micrograph showing a mold used in one example of the present
invention;
[0045] FIG. 4 is a drawing-substitute photograph, specifically an
AFM micrograph showing a nanoimprinted substrate surface obtained
in example 2, comparative example 1, and comparative example 2;
[0046] FIG. 5 is a drawing-substitute photograph, specifically an
AFM micrograph showing a nanoimprinted substrate surface obtained
in example 3 and comparative example 3;
[0047] FIG. 6 is a drawing-substitute photograph, specifically an
AFM micrograph showing a nanoimprinted substrate surface obtained
in example 4 and comparative example 4; and
[0048] FIG. 7 is a drawing-substitute photograph, specifically an
AFM micrograph showing a nanoimprinted substrate surface obtained
in example 5 and example 6.
DESCRIPTION OF THE EMBODIMENTS
[0049] The nanoimprinting resin, laminate including said resin,
printed substrate containing said resin, and method for
manufacturing a nanoimprinted substrate of the present invention
will be described more specifically below.
[0050] FIG. 2 shows a schematic view of the method for
manufacturing a nanoimprinted substrate of the present invention;
by (1) laminating a nanoimprinting resin 12 of the present
invention onto a substrate 11, (2) laminating a transfer-receiving
resin or a solution 13 containing a polymerizable monomer and a
photopolymerization initiator (may be referred to simply as
"transfer-receiving resin 13" below) on the nanoimprinting resin
12, (3) pressing a mold 14 against the laminate produced in (2),
and (4) detaching the mold 14 to transfer a pattern from the mold
14 to the transfer-receiving resin 13, it is possible to produce a
nanoimprinted substrate.
[0051] In the method for nanoimprinting shown in FIG. 2, when
thermal nanoimprinting is performed using a thermoplastic resin as
the transfer-receiving resin 13, step (3) of FIG. 2 may comprise
heating the laminate produced in step (2) to or above the glass
transition temperature of the transfer-receiving resin before the
mold 14 is pressed thereagainst, and then cooling the laminate to
or below the glass transition temperature of the transfer-receiving
resin 13; and step (4) may comprise detaching the mold 14. When
thermal nanoimprinting is performed using a thermosetting resin as
the transfer-receiving resin 13, step (3) may comprise pressing the
mold 14 at a temperature lower than the temperature at which the
transfer-receiving resin 13 cures, and then heating the laminate to
a temperature higher than the curing temperature of the
transfer-receiving resin 13; and step (4) may comprise detaching
the mold 14.
[0052] However, when optical nanoimprinting is performed, step (2)
may comprise applying a solution containing a polymerizable monomer
and a photopolymerization initiator; step (3) may comprise pressing
a mold 14 produced using a transparent material, and then
irradiating ultraviolet light or the like on the mold 14 side, or
on a base-material side if a transparent base material was used, to
cross-link/cure the polymerizable monomer; and step (4) may
comprise detaching the mold 14.
[0053] There is no particular limitation as to the material of the
substrate 11 as long as the substrate 11 can be nanoimprinted; the
material may be appropriately selected from: silicon, glass,
sapphire, gold, and other inorganic substances; and polyethylene
terephthalate (PET), polytetrafluoroethylene (PTFE),
polynaphthalene terephthalate (PEN), polycarbonate (PC),
triacetylcellulose (TAC), polymethylmethacrylate (PMMA),
methylmethacrylate-styrene copolymer (MS), and other resins.
[0054] The nanoimprinting resin 12 of the present invention is
configured from the resin represented by formula (1) below.
##STR00004##
[0055] (In the formula, each of R.sub.1-R.sub.5 independently
represents --H or --OH, at least one of R.sub.1-R.sub.5
representing --OH. R.sub.6 represents a C.sub.1-20 linear,
branched, or cyclic alkyl group, a C.sub.6-20 aryl group, or a
C.sub.7-20 aralkyl group. X represents an amide or an ester. Y
represents an amide or an ester, or may be absent. P represents an
integer from 1 to 10. m and n are integers equal to or greater than
1.)
[0056] The resin described above is an amphipathic resin configured
from a hydrophilic moiety in which at least one --OH group is
substituted in a benzene ring, and a hydrophobic moiety R.sub.6. At
least one of R.sub.1-R.sub.5 is a --OH group; when there are a
plurality of --OH groups, any position may be substituted.
Specifically, examples include: phenols having one --OH group;
catechols, resorcinols, and hydroquinones having two --OH groups;
pyrogallols and phloroglucinols having three --OH groups;
tetrahydroxybenzene having four --OH groups; and
pentahydroxybenzene having five --OH groups. To optimize the
hydrophilic-hydrophobic balance in the benzene ring described
above, there are preferably two to three --OH groups, and
particularly preferably two --OH groups. Furthermore, the --OH
groups are preferably adjacent to each other in order to orient the
--OH groups toward the substrate.
[0057] The p in formula (1) may be any integer from 1 to 10. X may
be selected from amides or esters. Y may also be selected from
amides or esters, or may be absent.
[0058] There is no particular limitation as to R.sub.6 as long as
R.sub.6 is hydrophobic and has affinity with the transfer-receiving
resin; examples include C.sub.1-20 linear, branched, or cyclic
alkyl groups; C.sub.6-20 aryl groups; and C.sub.7-20 aralkyl
groups.
[0059] Specific examples of C.sub.1-20 linear, branched, or cyclic
alkyl groups include methyl, ethyl, n-propyl, 2-propyl, n-butyl,
1-methylpropyl, 2-methylpyopyl, tert-butyl, n-pentyl,
1-methylbutyl, 1-ethylpropyl, tert-pentyl, 2-methylbutyl,
3-methylbutyl, 2,2-dimethylpropyl, n-hexyl, 1-methylpentyl,
1-ethylbutyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl,
2-methylpentane-3-yl, 3,3-dimethylbutyl, 2,2-dimethylbutyl,
1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl,
2,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, heptyl, octyl,
nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl,
hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, cyclopropyl,
cyclobutyl, cyclopentyl, and cyclohexyl. Among the alkyl groups
described above, a C.sub.1-12 alkyl group is preferred.
[0060] Specific examples of C.sub.6-20 aryl groups include phenyl,
indenyl, pentalenyl, naphthyl, azulenyl, fluorenyl, phenanthrenyl,
anthracenyl, acenaphthylenyl, biphenylenyl, naphthacenyl, and
pyrenyl.
[0061] Specific examples of C.sub.7-20 aralkyl groups include
benzyl, phenethyl, 1-phenylpropyl, 2-phenylpropyl, 3-phenylpropyl,
1-phenylbutyl, 2-phenylbutyl, 3-phenylbutyl, 4-phenylbutyl,
1-phenylpentylbutyl, 2-phenylpentylbutyl, 3-phenylpentylbutyl,
4-phenylpentylbutyl, 5-phenylpentylbutyl, 1-phenylhexylbutyl,
2-phenylhexylbutyl, 3-phenylhexylbutyl, 4-phenylhexylbutyl,
5-phenylhexylbutyl, 6-phenylhexylbutyl, 1-phenylheptyl,
1-phenyloctyl, 1-phenylnonyl, 1-phenyldecyl, 1-phenylundecyl,
1-phenyldodecyl, 1-phenyltridecyl, and 1-phenyltetradecyl.
[0062] m and n are integers equal to or greater than 1; the ratio
of m and n (m:n) is preferably 1:99-90:10, more preferably is
2:98-80:20, and particularly preferably is 5:95-20:80.
[0063] The resin represented by formula (1) is obtained by
polymerizing a compound represented by formula (2) below with a
compound represented by formula (3) below.
##STR00005##
[0064] (In the formula, each of R.sub.1-R.sub.5 independently
represents --H or --OH, at least one of R.sub.1-R.sub.5
representing --OH. X represents an amide or an ester. P represents
an integer from 1 to 10.)
##STR00006##
[0065] (In the formula, R.sub.6 represents a C.sub.1-20 linear,
branched, or cyclic alkyl group, a C.sub.6-20 aryl group, or a
C.sub.7-20 aralkyl group. Y represents an amide or an ester, or may
be absent.)
[0066] Examples of the compound represented by formula (2) above
include dopamine acrylamide, resorcin acrylamide, pyrogallol
acrylamide, phloroglucinol acrylamide, and tetrahydroxybenzene
acrylamide. Other examples include acrylamide and acrylic
derivatives bonded with phenol, catechol, resorcinol, hydroquinone,
pyrogallol, phloroglucinol, or tetrahydroxybenzene by an alkyl
group.
[0067] Examples of compounds used as the compound represented by
formula (2) above include dopamine hydrochloride, resorcin
alkylamine hydrochloride, pyrogallol alkylamine hydrochloride,
phloroglucinol alkylamine hydrochloride, tetrahydrobenzene
alkylamine hydrochloride, phenol alkyl carboxylic acid, resorcin
alkyl carboxylic acid, pyrogallol alkyl carboxylic acid,
phloroglucinol alkyl carboxylic acid, or tetrahydrobenzene alkyl
carboxylic acid as a starting material, and can be synthesized
using the procedure described below.
[0068] The starting material is added to a buffer solution obtained
by dissolving sodium bicarbonate (NaHCO.sub.3) and sodium borate in
water, and a tetrahydrofuran (THF) solution of methacrylate
anhydride is added dropwise while the buffer solution is stirred.
At this time, the pH of the solution is preferably maintained at or
above 8 using an aqueous solution of NaOH. The solution is stirred
overnight, after which the pH of the solution is adjusted to or
below 2 using HCl, ethyl acetate is added, and the product is
extracted. After the solution is dried using sodium sulfate
(Na.sub.2SO.sub.4), condensation and recrystallization are
performed using an evaporator. Next, a compound obtained by
filtration under reduced pressure is recovered and dried in a
vacuum, whereby the compound of formula (2), connected to the
starting material by a double bond, can be obtained.
[0069] When Y is an amide or ester and R.sub.6 is a C.sub.1-20
linear, branched, or cyclic alkyl group, examples of the compound
represented by formula (3) above include: methylacrylamide,
ethylacrylamide, n-propylacrylamide, 2-propylacrylamide,
n-butylacrylamide, 1-methylpropylacrylamide,
2-methylpropylacrylamide, tert-butylacrylamide, n-pentylacrylamide,
1-methylbutylacrylamide, 1-ethylpropylacrylamide,
tert-pentylacrylamide, 2-methylbutylacrylamide,
3-methylbutylacrylamide, 2,2-dimethylpropylacrylamide,
n-hexylacrylamide, 1-methylpentylacrylamide,
1-ethylbutylacrylamide, 2-methylpentylacrylamide,
3-methylpentylacrylamide, 4-methylpentylacrylamide,
2-methylpentane-3-ylacrylamide, 3,3-dimethylbutylacrylamide,
2,2-dimethylbutylacrylamide, 1,1-dimethylbutylacrylamide,
1,2-dimethylbutylacrylamide, 1,3-dimethylbutylacrylamide,
2,3-dimethylbutylacrylamide, 1-ethylbutylacrylamide,
2-ethylbutylacrylamide, heptylacrylamide, octylacrylamide,
nonylacrylamide, decylacrylamide, undecylacrylamide,
dodecylacrylamide, tridecylacrylamide, tetradecylacrylamide,
pentadecylacrylamide, hexadecylacrylamide, heptadecylacrylamide,
octadecylacrylamide, nonadecylacrylamide, icosylacrylamide,
cyclopropylacrylamide, cyclobutylacrylamide, cyclopentylacrylamide,
cyclohexylacrylamide, and other alkylacrylamides; and methyl ester,
ethyl ester, n-propyl ester, 2-propyl ester, n-butyl ester,
1-methylpropyl ester, 2-methylpropyl ester, tert-butyl ester,
n-pentyl ester, 1-methylbutyl ester, 1-ethylpropyl ester,
tert-pentyl ester, 2-methylbutyl ester, 3-methylbutyl ester,
2,2-dimethylpropyl ester, n-hexyl ester, 1-methylpentyl ester,
1-ethylbutyl ester, 2-methylpentyl ester, 3-methylpentyl ester,
4-methylpentyl ester, 2-methylpentane-3-yl ester, 3,3-dimethylbutyl
ester, 2,2-dimethylbutyl ester, 1,1-dimethylbutyl ester,
1,2-dimethylbutyl ester, 1,3-dimethylbutyl ester, 2,3-dimethylbutyl
ester, 1-ethylbutyl ester, 2-ethylbutyl ester, heptyl ester, octyl
ester, nonyl ester, decyl ester, undecyl ester, dodecyl ester,
tridecyl ester, tetradecyl ester, pentadecyl ester, hexadecyl
ester, heptadecyl ester, octadecyl ester, nonadecyl ester, icosyl
ester, cyclopropyl ester, cyclobutyl ester, cyclopentyl ester,
cyclohexyl ester, and other alkyl esters.
[0070] When Y is an amide or ester and R.sub.6 is a C.sub.6-20 aryl
group, examples include: phenylacrylamide, indenylacrylamide,
pentalenylacrylamide, naphthylacrylamide, azulenylacrylamide,
fluorenylacrylamide, phenanthrenylacrylamide,
anthracenylacrylamide, acenaphthylenylacrylamide,
biphenylenylacrylamide, naphthacenylacrylamide, pyrenylacrylamide,
and other arylacrylamides; and phenyl ester, indenyl ester,
pentalenyl ester, naphthyl ester, azulenyl ester, fluorenyl ester,
phenanthrenyl ester, anthracenyl ester, acenaphthylenyl ester,
biphenylenyl ester, naphthacenyl ester, pyrenyl ester, and other
aryl esters.
[0071] When Y is an amide or ester and R.sub.6 is a C.sub.7-20
aralkyl group, examples include: benzylacrylamide,
phenethylacrylamide, 1-phenylpropylacrylamide,
2-phenylpropylacrylamide, 3-phenylpropylacrylamide,
1-phenylbutylacrylamide, 2-phenylbutylacrylamide,
3-phenylbutylacrylamide, 4-phenylbutylacrylamide,
1-phenylpentylbutylacrylamide, 2-phenylpentylbutylacrylamide,
3-phenylpentylbutylacrylamide, 4-phenylpentylbutylacrylamide,
5-phenylpentylbutylacrylamide, 1-phenylhexylbutylacrylamide,
2-phenylhexylbutylacrylamide, 3-phenylhexylbutylacrylamide,
4-phenylhexylbutylacrylamide, 5-phenylhexylbutylacrylamide,
6-phenylhexylbutylacrylamide, 1-phenylheptylacrylamide,
1-phenyloctylacrylamide, 1-phenylnonylacrylamide,
1-phenyldecylacrylamide, 1-phenylundecylacrylamide,
1-phenyldodecylacrylamide, 1-phenyltridecylacrylamide,
1-phenyltetradecylacrylamide, and other aralkylacrylamides; and
benzyl ester, phenethyl ester, 1-phenylpropyl ester, 2-phenylpropyl
ester, 3-phenylpropyl ester, 1-phenylbutyl ester, 2-phenylbutyl
ester, 3-phenylbutyl ester, 4-phenylbutyl ester,
1-phenylpentylbutyl ester, 2-phenylpentylbutyl ester,
3-phenylpentylbutyl ester, 4-phenylpentylbutyl ester,
5-phenylpentylbutyl ester, 1-phenylhexylbutyl ester,
2-phenylhexylbutyl ester, 3-phenylhexylbutyl ester,
4-phenylhexylbutyl ester, 5-phenylhexylbutyl ester,
6-phenylhexylbutyl ester, 1-phenylheptyl ester, 1-phenyloctyl
ester, 1-phenylnonyl ester, 1-phenyldecyl ester, 1-phenylundecyl
ester, 1-phenyldodecyl ester, 1-phenyltridecyl ester,
1-phenyltetradecyl ester, and other aralkyl esters.
[0072] However, when Y is absent from formula (3) above and R.sub.6
is a C.sub.1-20 linear, branched, or cyclic alkyl group, examples
include propylene, 2-methyl-1-propylene, 1-butene,
2-methyl-1-butene, 3-methyl-1-butene, 3,3-dimethyl-1-butene,
3-methyl-2-ethyl-1-butene, 2,3-dimethyl-1-butene,
2-tertbutyl-3,3-dimethyl-1-butene, 1-pentene, 2-methyl-1-pentene,
3-methyl-1-pentene, 4-methyl-1-pentene, 2-methyl-3-ethyl-1-pentene,
2,4,4-trimethyl-1-pentene, 1-hexene, 2-ethyl-1-hexene,
2-butyl-1-hexene, 3,3-dimethyl-1-hexene, 5-methyl-1-hexene,
4-methyl-1-hexene, 3-methyl-1-hexene, 2,3-methyl-1-hexene,
4,5-dimethyl-1-hexene, 3,4,5-trimethyl-1-hexene,
3,3,5-trimethyl-1-hexene, 2,4-dimethyl-1-hexene,
2,4,4-trimethyl-1-hexene, 4,4-dimethyl-1-hexene, 3-ethyl-1-hexene,
2,3-dimethyl-1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene,
1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene,
1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-icosene,
cyclopropylene, cyclobutene, cyclopentene, and cyclohexene.
[0073] When Y is absent from formula (3) above and R.sub.6 is a
C.sub.6-20 aryl group, examples include vinylbenzene(styrene),
1-vinylindene, 5-vinylindene, 1-vinylpentalene, 1-vinylnaphthalene,
2-vinylnaphthalene, 2-vinylazulene, 9-vinyl-9H-fluorene,
2-vinyl-9H-fluorene, 1-vinylphenanthrene, 2-vinylphenanthrene,
3-vinylphenanthrene, 6-vinylphenanthrene, 8-vinylphenanthrene,
1-vinylanthracene, 2-vinylanthracene, 9-vinylanthracene,
1-vinylacenaphthylene, 2-vinylbiphenylene, 1-vinylnaphthacene,
2-vinylnaphthacene, 1-vinylpyrene, and 4-vinylpyrene.
[0074] When Y is absent from formula (3) above and R.sub.6 is a
C.sub.7-20 aralkyl group, examples include 3-phenyl-1-propylene,
2-phenyl-1-propylene, 4-phenyl-1-butene, 3-phenyl-1-butene,
2-phenyl-1-butene, 5-phenyl-1-pentene, 4-phenyl-1-pentene,
3-phenyl-1-pentene, 2-phenyl-1-pentene, 6-phenyl-1-hexene,
5-phenyl-1-hexene, 4-phenyl-1-hexene, 3-phenyl-1-hexene,
2-phenyl-1-hexene, 7-phenyl-1-heptene, 6-phenyl-1-heptene,
5-phenyl-1-heptene, 4-phenyl-1-heptene, 3-phenyl-1-heptene,
2-phenyl-1-heptene, 8-phenyl-1-octene, 7-phenyl-1-octene,
6-phenyl-1-octene, 5-phenyl-1-octene, 4-phenyl-1-octene,
3-phenyl-1-octene, 2-phenyl-1-octene, 9-phenyl-1-nonene,
8-phenyl-1-nonene, 7-phenyl-1-nonene, 6-phenyl-1-nonene,
5-phenyl-1-nonene, 4-phenyl-1-nonene, 3-phenyl-1-nonene,
2-phenyl-1-nonene, 10-phenyl-1-decene, 9-phenyl-1-decene,
8-phenyl-1-decene, 7-phenyl-1-decene, 6-phenyl-1-decene,
5-phenyl-1-decene, 4-phenyl-1-decene, 3-phenyl-1-decene,
2-phenyl-1-decene, 11-phenyl-1-undecene, 10-phenyl-1-undecene,
9-phenyl-1-undecene, 8-phenyl-1-undecene, 7-phenyl-1-undecene,
6-phenyl-1-undecene, 5-phenyl-1-undecene, 4-phenyl-1-undecene,
3-phenyl-1-undecene, 2-phenyl-1-undecene, 12-phenyl-1-dodecene,
11-phenyl-1-dodecene, 10-phenyl-1-dodecene, 9-phenyl-1-dodecene,
8-phenyl-1-dodecene, 7-phenyl-1-dodecene, 6-phenyl-1-dodecene,
5-phenyl-1-dodecene, 4-phenyl-1-dodecene, 3-phenyl-1-dodecene,
2-phenyl-1-dodecene, 13-phenyl-1-tridecene, 12-phenyl-1-tridecene,
11-phenyl-1-tridecene, 10-phenyl-1-tridecene, 9-phenyl-1-tridecene,
8-phenyl-1-tridecene, 7-phenyl-1-tridecene, 6-phenyl-1-tridecene,
5-phenyl-1-tridecene, 4-phenyl-1-tridecene, 3-phenyl-1-tridecene,
2-phenyl-1-tridecene, 14-phenyl-1-tetradecene,
13-phenyl-1-tetradecene, 12-phenyl-1-tetradecene,
11-phenyl-1-tetradecene, 10-phenyl-1-tetradecene,
9-phenyl-1-tetradecene, 8-phenyl-1-tetradecene,
7-phenyl-1-tetradecene, 6-phenyl-1-tetradecene,
5-phenyl-1-tetradecene, 4-phenyl-1-tetradecene,
3-phenyl-1-tetradecene, and 2-phenyl-1-tetradecene.
[0075] The amphipathic polymer of the present invention can be
synthesized using the compounds of formula (2) and formula (3)
above, using the procedure described below.
[0076] The compounds of formula (2) and formula (3) above, as well
as azobisisobutyronitrile and another radical polymerization
initiator, are dissolved in a mixed solvent of dimethyl sulfoxide
(DMSO) and benzene, and the resulting solution is subjected to
three freeze-pump-thaw cycles. The solution is heated to 60.degree.
C. in a nitrogen atmosphere, and free radical polymerization is
performed. After polymerization, the reaction solution is added
dropwise to acetonitrile and subjected to centrifugal separation,
after which the synthesized polymer is dried under reduced
pressure, whereby the nanoimprinting resin of the present invention
can be produced. The viscosity of the resulting resin and the
solubility for hydrogen bonds may decrease if the weight-average
molecular weight is too great, and the resin may not readily form a
coating if the weight-average molecular weight is too small;
therefore, the weight-average molecular weight of the resin is
preferably 5,000-500,000, and more preferably 10,000-100,000. It is
possible to adjust the weight-average molecular weight by adjusting
the proportions of the initiator and the monomer. The added amounts
of the compounds represented by formula (2) and formula (3) may be
adjusted using the ratio m:n. "Weight-average molecular weight" in
the present invention refers to the weight-average molecular weight
as measured through polystyrene reduction using HLC-8320GPC
manufactured by Tosoh Corp.
[0077] Examples of the nanoimprinting resin of the present
invention resulting from the method described above include the
resins illustrated below.
##STR00007##
[0078] Providing the nanoimprinting resin of the present invention
between a substrate 11 and a transfer-receiving resin 13 increases
the adhesiveness between the substrate 11 and the
transfer-receiving resin 13, and makes it possible to prevent the
transfer-receiving resin 13 from detaching from the substrate 11
when a mold is detached; therefore, either thermal nanoimprinting
or optical nanoimprinting can be used as the transfer method.
[0079] With thermal nanoimprinting, there are no particular
limitations as to the transfer-receiving resin 13 as long as the
transfer-receiving resin 13 is a thermoplastic resin or
thermosetting resin typically used in thermal nanoimprinting. When
a thermoplastic resin is used, the thermoplastic resin used as the
transfer-receiving resin is heated to or above the glass transition
temperature (Tg) thereof and softened, after which a mold having a
fine pattern formed thereon is pressed against the
transfer-receiving resin, and the transfer-receiving resin is
cooled to a temperature lower than the glass transition temperature
thereof, whereby the fine pattern is transferred; therefore, the
thermoplastic resin preferably has a glass transition temperature
lower than the heating temperature used during transferal. When a
thermosetting resin is used, the thermosetting resin preferably has
a glass transition temperature higher than the heating temperature
used when the mold having a fine pattern formed thereon is pressed
against the transfer-receiving resin, from the standpoint of
compatibility with the thermal nanoimprinting method.
[0080] Examples of the thermoplastic resin include polyethylene
(PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene
(PS), polyvinyl acetate (PVAc), polytetrafluoroethylene (PTFE),
acrylonitrile butadiene styrene resin (ABS resin), AS resin,
acrylic resin (PMMA), polyurethane resin (TPU), polyvinyl alcohol
(PVA), polycarbonate (PC), polysulfone (PSF), polylactatic acid
(PLA), polycaprolactone (PCL), polybutadiene (BR), and polyisoprene
(IR).
[0081] Examples of the thermosetting resin include phenol resin
(PF), epoxy resin (EP), melamine resin (MF), urea resin (UF),
unsaturated polyester resin (UP), alkyd resin, polyurethane (PUR),
and thermosetting polyimide (PI). An appropriate resin may be
selected while taking the temperature during mold pressing into
consideration.
[0082] There is no particular limitation as to the photocuring
resin used in optical nanoimprinting as long as the photocuring
resin is conventionally used in the field; examples of the
photocuring resin include photocuring resins that can be cured
using ultraviolet or visible light and have polyester acrylate,
acrylic, epoxy acrylate, urethane acrylate, or another type of
unsaturated double bond. The photocuring resin includes a
polymerizable monomer, or an oligomer obtained by cross-linking a
polymerizable polymer with the monomer, and can be cured by
cross-linking using a photopolymerization initiator.
[0083] As the monomer there is used a material comprising a monomer
or oligomer having one or more functional groups, the monomer or
oligomer being subjected to ion polymerization or radical
polymerization using ions or radicals generated by irradiating a
photopolymerization initiator with curing energy rays, to increase
the molecular weight or form a cross-linking structure. The
"functional groups" referred to here are vinyl groups, carboxyl
groups, hydroxyl groups, or other atom groups or bonding schemes
used as the source of the reaction. Examples of such monomers and
oligomers include epoxy acrylate, urethane acrylate, polyester
acrylate, polyether acrylate, silicon acrylate, and other acrylics;
and unsaturated polyester/styrene, polyene/styrene, and other
non-acrylics; however, acrylics are preferred due to curing speed
and wider selection of materials. Representative examples of such
acrylics are illustrated below.
[0084] Examples of monofunctional groups can include 2-ethylhexyl
acrylate, 2-ethylhexyl acrylate/EO adduct, ethoxy diethyleneglycol
acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,
2-hydroxyethyl acrylate/caprolactone adduct, 2-phenoxyethyl
acrylate, phenoxy diethyleneglycol acrylate, nonylphenol
acrylate/EO adduct, an acrylate obtained by adding captrolactone to
nonylphenol/EO adduct, 2-hydroxy-3-phenoxypropyl acrylate,
tetrahydrofurfuryl acrylate, furfuryl alcohol acrylate/caprolactone
adduct, acryloyl morpholine, dicyclopentenyl acrylate,
dicyclopentanyl acrylate, dicyclopentenyloxyethyl acrylate,
isobornyl acrylate, 4,4-dimethyl-1,3-dioxolan acrylate/caprolactone
adduct, and 3-methyl-5,5-dimethyl-1,3-dioxolan
acrylate/caprolactone adduct.
[0085] Examples of polyfunctional groups can include hexanediol
diacrylate, neopentylglycol diacrylate, polyethyleneglycol
diacrylate, tripropyleneglycol diacrylate, hydroxypivalic acid
neopentylglycol ester diacrylate, hydroxypivalic acid
neopentylglycol ester diacrylate/caprolactone adduct, 1,6-hexandiol
diglycidyl ether/acrylate adduct, diacrylate of acetalized compound
of hydroxypivalaldehyde and trimethylolpropane,
2,2-bis[4-(acryloyloxydiethoxy)phenyl]propane,
2,2-bis[4-(acryloyloxydiethoxy)phenyl]methane, hydrogenated
diacrylate/bisphenolethyleneoxide adduct, tricyclodecanedimethanol
diacrylate, trimethylolpropane triacrylate, pentaerythritol
triacrylate, triacrylate/trimethylolpropanepropyleneoxide adduct,
triacrylate/glycerinepropyleneoxide adduct, dipentaerythritol
hexacrylate pentacrylate mixture, dipentaerythritol
acrylate/caprolactone adduct, tris(acryloyloxyethyl)isocyanurate,
and 2-acryloyloxyethyl phosphate.
[0086] There is no particular limitation as to the
photopolymerization initiator to be used; the substance used can be
selected from well-known substances. Specifically, examples
include: acetophenones, benzophenones, Michler's ketones, benzyls,
benzoins, benzoin ethers, benzyldimethyl ketals, benzoin benzoates,
.alpha.-acyloxime esters, and other carbonyl compounds;
tetramethylthiuram monosulfide, thioxanthones, and other sulfur
compounds; and 2,4,6-trimethylbenzoyldiphenylphosphine oxide and
other phosphorus compounds.
[0087] The nanoimprinting resin of the present invention can,
without modification, improve the adhesiveness of a substrate with
a photocuring resin or other transfer-receiving resin 13; however,
in order to further improve adhesiveness, introducing an epoxy
group, an azido group, a vinyl group, or the like to the end of the
linear, branched, or cyclic alkyl group, aryl group, or aralkyl
group represented by R.sub.6 in formula (1) and integrally curing
the resin when the polymerizable monomers are cured makes it
possible to further improve adhesiveness.
[0088] Examples of the compound formed by guiding an epoxy group,
azido group, vinyl group, or the like to the end described above
include glycidyl acrylate, azide acrylate, and 1,2-butadiene.
[0089] The fine pattern on the mold 14 may be formed using a
well-known method in accordance with the desired mold material and
accuracy. For example, it is possible to utilize photolithography,
focused ion beam lithography, electron-beam printing, cutting
processes, and other such mechanical processes, as well as replica
production by molding from a mold matrix, plating, or the like, and
other such means.
[0090] The nanoimprinting resin 12 and the transfer-receiving resin
13 of the present invention can be laminated on the substrate by
first dissolving chloroform or another organic solvent used as a
hydrophobic polymer in water used as a water-soluble polymer, and
then laminating the nanoimprinting resin 12 and the
transfer-receiving resin 13 in the stated order by spin-coating,
casting, or another such method. The thicknesses of the
nanoimprinting resin 12 and the transfer-receiving resin 13 are
preferably 0.1-100 .mu.m. When a solution comprising a
polymerizable monomer and a photopolymerization initiator is used
as the transfer-receiving resin 13, the solution layer formed by
spin-coating or another such method may be set to a thickness of
0.1-100 .mu.m.
[0091] The present invention is specifically described in the
examples given below, which are provided merely to describe the
present invention and to serve as a reference for specific
embodiments thereof. Although these examples describe particular,
specific embodiments of the present invention, they do not
represent any limitation or restriction of the claims of the
invention disclosed in the present application.
EXAMPLES
Production of Nanoimprinting Mold
[0092] A chloroform solution (10 mg/mL) of polystyrene (182427
manufactured by Sigma-Aldrich Corp., weight-average molecular
weight: approximately 280,000) was cast on a silicon substrate in
which holes 1 .mu.m in diameter were formed at 1-.mu.m intervals in
a quadrangular grid, and the substrate was dried at ordinary
temperatures, whereby a polystyrene coating was produced. The
substrate was then immersed in ethanol, and the polystyrene
coating, which had protruding structures, was detached from the
silicon substrate using a pincette. The resulting polystyrene
coating was placed in a petri dish so that the protruding
structures faced upwards, and a 10:1 mixture (Dow Corning Toray
Co., Ltd., SylPot184.RTM.)) of a polydimethylsiloxane elastomer
(PDMS) precursor and a platinum catalyst was cast and then defoamed
using low pressure, after which the polystyrene coating was cured
at 70.degree. C. over five hours. After curing, the polystyrene
coating was dissolved using chloroform (or benzene), whereby a
polydimethylsiloxane elastomer mold (may be referred to as "PDMS
mold" below) was produced. A micrograph of the resulting PDMS mold,
captured by an atomic force microscope (AFM, manufactured by Seiko
Instruments Inc., SPI-400), is shown in FIG. 3.
Example 1
Production of Nanoimprinting Resin
[0093] 4.0 g of sodium bicarbonate (198-01315 manufactured by Wako
Pure Chemical Ind., Ltd.), 10.0 g of sodium borate (192-01455
manufactured by Wako Pure Chemical Ind., Ltd.), and 5.0 g of
dopamine chloride (DOPA, H8502 manufactured by Sigma-Aldrich Corp.)
were added to 100 mL of ultrapure water (Milli-Q) produced using an
ultrapure water production system made by Millipore. A solution
obtained by dissolving 4.7 mL of methacrylate anhydride (276685
manufactured by Sigma-Aldrich Corp.) into 25 mL of tetrahydrofuran
(THF: 200-00486 manufactured by Wako Pure Chemical Ind., Ltd.) was
added dropwise while the solution obtained as described above was
stirred. At this time, the pH of the solution was maintained at or
above 8 using 1 mol/L of an aqueous solution of NaOH. The solution
was stirred overnight, after which the pH of the solution was
adjusted to or below 2 using 6 mol/L of HCl, ethyl acetate was
added, and the product was extracted. After the solution was dried
using sodium sulfate, condensation and recrystallization were
performed using an evaporator. Dopamine methacrylamide (DMA)
obtained by filtration under reduced pressure was recovered and
dried in a vacuum. To obtain the amphipathic polymer of the present
invention, 0.673 mmol of DMA, 5.43 mmol of N-dodecylacrylamide
(NDA), and 0.125 mmol of azobisisobutyronitrile were dissolved in a
3:50 mixed solvent of dimethyl sulfoxide (DMSO) and benzene, and
the resulting solution was subjected to three freeze-pump-thaw
cycles. The solution was heated to 60.degree. C. in a nitrogen
atmosphere, and free radical polymerization was performed. After
polymerization, the reaction solution was added dropwise to
acetonitrile and subjected to centrifugal separation, after which
the synthesized polymer was dried under reduced pressure, whereby
the nanoimprinting resin (may be referred to as "PDOPA resin"
below) of the present invention was produced.
[Nanoimprinting Test (Effect of Nanoimprinting Temperature)]
Example 2
[0094] A chloroform solution (2 mg/mL) of the PDOPA resin obtained
as in example 1 was spin-coated at 3,000 rpm onto a glass substrate
(cover glass manufactured by Matsunami Glass Ind., Ltd.), and then
a chloroform solution (2 mg/mL) of polystyrene (PS: 182427
manufactured by Sigma-Aldrich Corp., glass transition point
approximately 100.degree. C.) was spin-coated thereon at 3,000 rpm,
whereby a thin-film laminate was produced on the glass substrate.
Next, the substrate was disposed on a lower hot stage of a hot
stage disposed vertically in a reduced-pressure chamber, the PDMS
mold was arranged on the substrate, and the upper hot stage was
pressed at a pressure of approximately 100 kPa. The substrate was
then annealed under reduced pressure (a pressure of 10.sup.-1 Pa)
at 100.degree. C. over one hour, after which air was drawn in and
the interior of the pressure chamber was returned to a normal
pressure. The hot stage was cooled to a temperature of 50.degree.
C., and then the pressure on the hot stage was released, whereby
nanoimprinting was performed. The surface structures on the surface
of the resulting nanoimprinted substrate were observed using an
atomic force microscope (AFM, manufactured by Seiko Instruments
Inc., SPI-400). FIG. 4(1) is an AFM micrograph showing the
nanoimprinted substrate surface obtained in example 2.
Comparative Example 1
[0095] Nanoimprinting was performed using the same procedure as in
example 1, except that no spin-coating of the chloroform solution
of the PDOPA resin was performed. FIG. 4(2) is an AFM micrograph
showing the nanoimprinted substrate surface obtained in comparative
example 1.
Comparative Example 2
[0096] Nanoimprinting was performed using the same procedure as in
example 1, except that no spin-coating of the chloroform solution
of the PDOPA resin was performed, and the hot stage was cooled to a
temperature of 30.degree. C. after annealing. FIG. 4(3) is an AFM
micrograph showing the nanoimprinted substrate surface obtained in
comparative example 2.
[0097] As shown in FIG. 4(3), when no PDOPA resin layer was
provided, sufficiently cooling the glass substrate to 30.degree. C.
made it possible to transfer a pattern from the PDMS mold to the
polystyrene layer, although the resolution was low. However, when
the cooling temperature of the glass substrate was set higher
(50.degree. C.), the polystyrene layer provided on the glass
substrate was detached therefrom when the PDMS mold was detached,
and the pattern could not be transferred from the PDMS mold.
Conversely, in example 1, in which the PDOPA resin layer was
provided between the glass substrate and the polystyrene layer, the
polystyrene layer did not detach when the PDMS mold was detached,
even when the cooling temperature of the glass substrate was
50.degree. C., making it possible to accurately transfer the
pattern from the PDMS mold.
[Nanoimprinting Test (Effect of Substrate)]
Example 3
[0098] Nanoimprinting was performed using the same procedure as in
example 2, except that polyethylene terephthalate (PET,
manufactured by Sanplatec Corp.) was used as the substrate instead
of glass. FIG. 5(1) is an AFM micrograph showing the nanoimprinted
substrate surface obtained in example 2.
Comparative Example 3
[0099] Nanoimprinting was performed using the same procedure as in
example 3, except that no spin-coating of the chloroform solution
of the PDOPA resin was performed. FIG. 5(2) is an AFM micrograph
showing the nanoimprinted substrate surface obtained in comparative
example 3.
Example 4
[0100] Nanoimprinting was performed using the same procedure as in
example 2, except that polytetrafluoroethylene (PTFE, manufactured
by Sanplatec Corp.) was used as the substrate instead of glass.
FIG. 6(1) is an AFM micrograph showing the nanoimprinted substrate
surface obtained in example 4.
Comparative Example 4
[0101] Nanoimprinting was performed using the same procedure as in
example 4, except that no spin-coating of the chloroform solution
of the PDOPA resin was performed, and polytetrafluoroethylene was
laminated by casting instead of by spin-coating. FIG. 6(2) is an
AFM micrograph showing the nanoimprinted substrate surface obtained
in comparative example 3.
[0102] As is apparent from comparative examples 1, 3, and 4, when
nanoimprinting was performed without providing a PDOPA resin layer,
it was possible to transfer a pattern from the PDMS mold to the
polystyrene layer, as shown in FIG. 5(2), in comparative example 3,
in which highly hydrophobic PET was used as the substrate; however,
when lowly hydrophobic glass in comparative example 1, or PTFE in
comparative example 4, was used as the substrate, it was impossible
to transfer a pattern from the PDMS mold to the polystyrene layer,
as shown in FIGS. 4(2) and 6(2). Conversely, in examples 2-4, in
which the PDOPA resin layer was provided between the substrate and
the polystyrene layer, it was possible to accurately transfer the
pattern from the PDMS mold to the polystyrene layer, as shown in
FIGS. 4(1), 5(1), and 6(1), irrespective of the type of
substrate.
[Nanoimprinting Test (Effect of Laminate Resin)]
Example 5
[0103] Nanoimprinting was performed using the same procedure as in
example 2, except that an aqueous solution (10 mg/mL) of polyvinyl
alcohol (PVA, manufactured by Wako Pure Chemical Ind., Ltd., glass
transition temperature approximately 85.degree. C.) was used
instead of polystyrene. FIG. 7(1) is an AFM micrograph showing the
nanoimprinted substrate surface obtained in example 5.
Example 6
[0104] Nanoimprinting was performed using the same procedure as in
example 2, except that a chloroform solution (5 mg/mL) of
polyvinylbutyral (PVB, manufactured by Wako Pure Chemical Ind.,
Ltd., glass transition temperature approximately 70.degree. C.) was
used instead of polystyrene. FIG. 7(2) is an AFM micrograph showing
the nanoimprinted substrate surface obtained in example 6.
[0105] As is apparent from examples 2, 5, and 6, when the PDOPA
resin layer was provided between the substrate and the resin layer
to which the PDMS mold was to be transferred, it was possible to
accurately transfer the pattern from the PDMS mold, irrespective of
the hydrophobicity (examples 2 and 6) or hydrophilicity (example 5)
of the resin layer to which the PDMS mold was to be
transferred.
[0106] As is apparent from examples 1-6 and comparative examples
1-4 described above, providing the PDOPA resin layer of the present
invention between the substrate and the resin layer to which the
PDMS mold is to be transferred makes it possible to transfer the
pattern from the PDMS mold to the transfer-receiving resin,
irrespective of the type of substrate and the type of resin layer
to which the PDMS mold is to be transferred, even when cooling is
not sufficiently performed after nanoimprinting.
INDUSTRIAL APPLICABILITY
[0107] Using the nanoimprinting resin of the present invention
makes it possible to perform nanoimprinting irrespective of the
type of substrate and the type of transfer-receiving resin layer to
which a mold is to be transferred, and furthermore makes it
unnecessary to sufficiently cool the substrate when the mold is
detached. Therefore, because it is possible to perform
nanoimprinting using various types of substrate and resin,
materials that could not be shaped by conventional nanoimprinting
can be used as substrates; therefore, it is possible, e.g., to
impart a shape suitable for a cell scaffold to a Teflon.RTM.
substrate used as a medical material, or to shape a polymeric
anti-reflective film on glass. Furthermore, because sufficient
cooling after mold detachment is unnecessary, it is possible to
reduce manufacturing time and improve manufacturing yield,
therefore making nanoimprinting more widely useful.
[0108] Therefore, the present invention can be used in
semiconductor integrated circuits, members of liquid crystal
display devices, optical components, recording media, optical
waveguides, protective films, microreactors, nanodevices, chips for
medical separation analysis, and other products.
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