U.S. patent application number 13/090895 was filed with the patent office on 2011-09-15 for ink composition and method of fabricating liquid crystal display device using the same.
Invention is credited to Byong-Hoo Kim, Byung-Geol Kim, Byung-Uk Kim, Jin-Wuk Kim, Sung-Hee Kim, Ki-Beom Lee, Myoung-Soo Lee, Seung-Hyup Shin, Jun-Young Song, Soon-Sung Yoo.
Application Number | 20110224335 13/090895 |
Document ID | / |
Family ID | 42165569 |
Filed Date | 2011-09-15 |
United States Patent
Application |
20110224335 |
Kind Code |
A1 |
Kim; Sung-Hee ; et
al. |
September 15, 2011 |
INK COMPOSITION AND METHOD OF FABRICATING LIQUID CRYSTAL DISPLAY
DEVICE USING THE SAME
Abstract
Disclosed are an ink composition and a method for fabricating a
liquid crystal display (LCD) device using the same, wherein in
forming patterns of the LCD device using an imprint lithography and
a roll printing, an ink composition with high thermal resistance,
consisting of polymer resin and additive both endurable even at a
high temperature is used to form fine patterns with constantly
maintaining pattern linewidths and line intervals, the ink
composition consisting of 5-45% by weight of polymer resin, 5-45%
by weight of additive added to retain thermal stability, and 50-90%
by weight of organic solvent, wherein the ink composition is
endurable even at a high temperature of 90-250.degree. C.
Inventors: |
Kim; Sung-Hee; (Gyeonggi-do,
KR) ; Yoo; Soon-Sung; (Gyeonggi-do, KR) ; Kim;
Jin-Wuk; (Gyeonggi-do, KR) ; Kim; Byung-Geol;
(Gyeonggi-do, KR) ; Kim; Byung-Uk; (Gyeonggi-do,
KR) ; Lee; Ki-Beom; (Gyeonggi-do, KR) ; Kim;
Byong-Hoo; (Gyeonggi-do, KR) ; Shin; Seung-Hyup;
(Gyeonggi-do, KR) ; Song; Jun-Young; (Gyeonggi-do,
KR) ; Lee; Myoung-Soo; (Gyeonggi-do, KR) |
Family ID: |
42165569 |
Appl. No.: |
13/090895 |
Filed: |
April 20, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12613961 |
Nov 6, 2009 |
7935552 |
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13090895 |
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Current U.S.
Class: |
524/93 ; 524/100;
524/101; 524/106; 524/110; 524/141; 524/156; 524/186; 524/226;
524/260; 524/291; 524/358; 524/384; 524/387; 524/556; 524/594;
524/95 |
Current CPC
Class: |
B82Y 40/00 20130101;
G03F 7/0002 20130101; C09D 11/02 20130101; C09D 11/033 20130101;
B82Y 10/00 20130101 |
Class at
Publication: |
524/93 ; 524/594;
524/556; 524/387; 524/291; 524/156; 524/186; 524/100; 524/95;
524/106; 524/110; 524/226; 524/260; 524/358; 524/384; 524/101;
524/141 |
International
Class: |
C09D 11/10 20060101
C09D011/10 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 7, 2008 |
KR |
10-2008-0110624 |
Claims
1. An ink composition consisting of: 5-45% by weight of polymer
resin; 5-45% by weight of additive added to retain thermal
stability; and 50-90% by weight of organic solvent, wherein the ink
composition is endurable even at a high temperature of
90-250.degree. C.
2. The ink composition of claim 1, wherein the ink composition is
used for forming patterns using an imprint lithography or a roll
printing.
3. The ink composition of claim 1, wherein the polymer resin is one
or more selected from a group consisting of novolak resin, acryl
resin and a is compound thereof.
4. The ink composition of claim 1, wherein the additive is one or
more selected from a group consisting of pentaerythritol, metyl
gallate, propyl gallate, lauryl gallate, octylgallate, metol,
tyramine hydrochloride, 1-(3-hydroxyphenyl)piperazine,
4-bromo-2-(5-isoxazolyl)phenol, 4-(imidazole-1-yl)phenol, apigenin,
2-(4,5-dihydro-1H-imidazole-2-yl)phenol,
3-(4,5-dihydro-1H-imidazole-2-yl)phenol,
4-(4,5-dihydro-1H-imidazole-2-yl)phenol,
4-nitro-2-(1H-pyrazole-3-yl)phenol,
2-(2-hydroxyphenyl)-1H-benzimidazole,
4-(4-methyl-4,5-dihydro-1H-imidazole-2-yl)phenol,
1-amino-2-naphthol hydrochloride, 2,4-diamino phenol
dihydrochloride, 2-acetamidophenol, 2-amino-3-nitrophenol,
2-amino-4-chloro-5-nitrophenol, 2-amino-5-nitrophenol,
3-amino-2-naphthol, 3-methoxytyramine hydrochloride,
4,7-dimethoxy-1,10-phenanthroline, 4-amino-1-naphthol
hydrochloride, 4-amino-3-chlorophenol hydrochloride, 4-aminophenol
hydrochloride, 4-tritylphenol, 8-amino-2-naphthol, biochanin A,
chloranil, pentaBromo-phenol, quercetin dihydrate, fisetin,
1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,
tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,
octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,
2,5-bis(1,1-dimethylpropyl)-1,4-benzenediol,
1,1,3-tris-(2-methyl-4-hydroxy-5-tert-butylphenyl)butane,
triethyleneglycol-bis(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate,
2,2-methylenebis(4-methyl-6-(1-methylcyclohexyl)-phenol), and
tris(2,4-di-tert-butylphenyl)phosphate.
5. The ink composition of claim 1, further consisting of 0.01-3% by
weight of surfactant of total 100% by weight of the ink
composition, the surfactant is preventing stains and hole marks of
ink material from being generated on silicon polymer.
6. The ink composition of claim 1, further consisting of 0.01-5% by
weight of adhesive sensitizer of total 100% by weight of the ink
composition, the adhesive sensitizer improving adhesive property
with a lower layer.
7. The ink composition of claim 1, further consisting of 0.001-3.0%
by weight of visible compound of total 100% by weight of the ink
composition, the visible compound remarkably ensuring visibility of
the ink composition and improving pattern transfer capability due
to being soluble in the polymer resin.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a divisional of U.S. patent application Ser. No.
12/613,961, filed Nov. 6, 2009, and also claims the benefit of
Korean Application No. 10-2008-0110624, filed Nov. 7, 2008, both of
which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to ink composition, and
particularly, to an ink composition with high heat resistance for
imprint lithography and roll printing, is capable of forming
accurate fine patterns, and a method of fabricating a liquid
crystal display (LCD) device using the same.
[0004] 2. Background of the Invention
[0005] Recently, as information displaying becomes more attractive
and demands on the use of portable information media increase,
studies and commercialization of lighter, thinner flat panel
displays (FPDs), substituting a cathode ray tube (CRT) as the
existing display device, have been broadly conducted. Especially,
among the FPDs, a liquid crystal display (LCD) device is to display
images by using optical anisotropic property of liquid crystal. The
LCD device is excellent in resolution, color rendering property,
image quality and the like, and thus widely being applied to
notebooks, desktop monitors and the like.
[0006] The LCD device includes a color filter substrate, an array
substrate, and a liquid crystal layer interposed between the color
filter substrate and the array substrate.
[0007] An active matrix method, which is a normally used driving
method in the LCD device, is configured to drive liquid crystal of
pixel units by employing amorphous silicon thin film transistors
(a-Si TFTs) as switching devices.
[0008] Hereinafter, a structure of a related art LCD device will be
described in detail with reference to FIG. 1.
[0009] FIG. 1 is a disassembled perspective view schematically
showing a related art LCD device.
[0010] As shown in FIG. 1, the LCD device includes a color filter
substrate 5, an array substrate 10, and a liquid crystal layer 30
interposed between the color filter substrate 5 and the array
substrate 10.
[0011] The color filter substrate 5 is provided with a color filter
C having a plurality of sub color filters 7 for rendering red (R),
green (G) and blue (B) colors, a black matrix 6 for dividing
between adjacent sub color filters 7 and blocking light transmitted
through the liquid crystal layer 30, and a transparent common
electrode 8 for applying a voltage to the liquid crystal layer
30.
[0012] Also, the array substrate 10 is provided with a plurality of
gate lines 16 and data lines 17 arranged in horizontal and vertical
directions for defining a plurality of pixel regions P, thin film
transistor T as switching devices formed at intersections between
the gate lines 16 and the data lines 17, and pixel regions 18
formed on the respective pixel regions P.
[0013] The color filter substrate 5 and the array substrate 10
having such structure are attached to face each other by a sealant
(not shown) formed at an outer periphery of an image display
region, thereby constructing an LCD panel. The attachment between
the color filter substrate 5 and the array substrate 10 may be
implemented by an attachment key (not shown) formed either at the
color filter substrate 5 or at the array substrate 10.
[0014] The fabrication of the LCD device includes plural times of a
photolithography process required to produce the array substrate
having TFTs.
[0015] Also, for forming fine patterns, which are applied to
information storage, compact sensors, photonic crystal and optical
elements, micro-electro mechanical systems, display devices and
semiconductors, the photolithography process conducted to form fine
patterns using light is performed.
[0016] The photolithography process denotes a series of processes
by which patterns printed on a mask are transferred on a thin
film-deposited substrate so as to form desired patterns. The
photolithography process is implemented through a plurality of
complicated processes including photoresist coating, alignment and
exposure, development and the like.
[0017] First, after coating photoresist as a photo resistor on a
thin film on which preset patterns are to be formed, a
pattern-formed photomask is aligned with the thin film and then
exposed to light. Here, the photomask used is divided into a preset
transparent region and a blocking region. Light transmitted through
the transparent region may chemically change the photoresist.
[0018] The chemical change in the photoresist may depend on a type
of photoresist. For a positive photoresist, regions exposed to
light become soluble in a developer solution. To the contrary, for
a negative photoresist, regions exposed to light become insoluble
in the developer solution. The description will exemplarily be
given herein of the case of using the positive photoresist.
[0019] Following the exposure process, the exposed regions of the
photoresist are removed by a developer solution, thereby generating
preset photoresist patterns on the thin film.
[0020] Afterwards, the thin film is etched to be conformable with
the photoresist patterns and the rest of photoresist patterns are
then removed, thereby making a preset form of thin film
patterns.
[0021] In the photolithography process, a linewidth of a circuit or
pattern is determined according to wavelength of light used in the
exposure process. Considering the current technical standard, it is
difficult to form fine patterns less than 70 nm on a substrate
through the photolithography process due to light interference.
[0022] Further, as patterns are getting supermicronized, an initial
investment cost is increased due to an expensive exposure
equipment, masks with high resolution are required and the like,
resulting in excessively increasing process cost. In addition,
since the complicated process, including exposure, baking after
exposure, development, baking after development, etching, washing
and the like, should be carried out every time forming patterns, it
takes a long time to carry out such processes and the
photolithography process should be repeated plural times, thereby
lowering productivity.
[0023] To solve such problems, an imprint lithography and a roll
printing have been introduced. The imprint lithography is a method,
initially invented by Stephen Chou et al. from the Princeton
University in the United States, for carving nano-scaled patterns.
According to this method, desired forms are previously made on a
surface of inorganic material or polymer with relatively strong
intensity and then fine patterns are formed as the previously made
forms are affixed onto another material. In detail, an inorganic
material or polymer mold having desired fine patterns pre-formed
thereon is attached onto a curable composition coated on a metallic
film or an organic layer to be thermally cured or photocured,
thereby forming patterns. This method has advantages in a simple
process and an effective fine pattern formation, compared to the
existing photolithography.
[0024] The roll printing method has been disclosed, for example, in
Korean Patent Application No. 2006-0005482 (Laid Open Application
No. 10-2007-76292), entitled "roll printing apparatus and method of
fabricating display device using the same." According to the roll
printing method, in place of the high resolution mask used when
forming patterns through the existing photolithography, silicon
polymer and cliche are used to transfer patterns directly on a
substrate to desirably form fine patterns thereon, thereby forming
the fine patterns.
[0025] However, in a low temperature baking process after the fine
pattern formation, a problem of disappearance of a metal substrate,
which is to be protected upon etching process may be caused by a
decrease in adhesive force between an ink composition and a
substrate to desirably form patterns thereon. Furthermore, in a
high temperature baking process, the adhesive force between the
substrate to desirably form patterns thereon and the ink
composition is increased but a pattern linewidth and line interval
formed by the ink composition runs down to occur deformation, which
may cause an excessive defect, for example, defective patterns,
resulting in limitation on a consecutive transfer of fine patterns
and difficulty in an enhancement of accuracy of the fine
patterns.
SUMMARY OF THE INVENTION
[0026] Therefore, to solve the problems of the related art, an
object of the present invention is to provide a method of
fabricating an LCD device by employing an imprint lithography and a
roll printing, substituting the photolithography.
[0027] Another object of the present invention is to provide an ink
composition for an imprint lithography and a roll printing, capable
of enhancing pattern accuracy as well as uniformly retaining a
linewidth and a line interval of the pattern by using a polymer
resin and an additive both endurable even at a high temperature,
and a method of fabricating an LCD device using the same.
[0028] The foregoing and other objects, features, aspects and
advantages of the present invention will become more apparent from
the following detailed description of the present invention when
taken in conjunction with the accompanying drawings.
[0029] To achieve these and other advantages and in accordance with
the purpose of the present invention, as embodied and broadly
described herein, there is provided an ink composition consisting
of 5-45% by weight of polymer resin, 5-45% by weight of additive
added to retain thermal stability, and 50-90% by weight of organic
solvent, wherein the ink composition is endurable even at a high
temperature of 90-250.degree. C.
[0030] In one aspect of the present invention, there is provided a
method of fabricating an LCD device including, preparing a mother
substrate having a plurality of array substrates or a plurality of
color filter substrates, performing an array process for the array
substrate and a color filter process for the color filter
substrates, forming an alignment layer on the surface of the mother
substrate, performing rubbing of the mother substrate, attaching a
pair of mother substrates having completely rubbed, and cutting the
attached mother substrate into a plurality of unit liquid crystal
display panels, wherein upon executing the array process and the
color filter substrate, an imprint lithography and roll printing
process is executed to form fine patterns, the imprint lithography
and roll printing process using an ink composition consisting of
5-45% by weight of polymer resin, 5-45% by weight of additive added
to retain thermal stability, and 50-90% by weight of organic
solvent, the ink composition endurable even at a high temperature
of 90-250.degree. C.
[0031] As described above, in the ink composition and a method of
fabricating an LCD device in accordance with the present invention,
polymer resin and additive both endurable even at a high
temperature are used so as to constantly maintain pattern linewidth
and line interval, which allows consecutive transfer of fine
patterns, resulting in improvement of pattern accuracy, yield and
process efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and together with the description serve to explain
the principles of the invention.
[0033] In the drawings:
[0034] FIG. 1 is a disassembled perspective view schematically
showing a related art LCD device;
[0035] FIG. 2 is a table showing comparison results of ink
compositions, fabricated using different additives, from first and
second embodiments and first and second comparisons;
[0036] FIG. 3 is a table showing comparison results of each pattern
transcription rate of the ink compositions from the first and
second embodiments and the first and second comparisons of FIG.
2;
[0037] FIG. 4 is an optical microscopic photo showing a
heat-treated surface of a fine pattern formed by using the ink
composition fabricated in accordance with the first embodiment of
the present invention;
[0038] FIG. 5 is an optical microscopic photo showing a
heat-treated surface of a fine pattern formed by using the ink
composition fabricated in accordance with the second embodiment of
the present invention;
[0039] FIG. 6 is an optical microscopic photo showing a
heat-treated surface of a fine pattern formed by using the ink
composition fabricated in accordance with the first Comparison;
[0040] FIG. 7 is an optical microscopic photo showing a
heat-treated surface of a fine pattern formed by using the ink
composition fabricated in accordance with the second
Comparison;
[0041] FIG. 8 is a flowchart sequentially showing a method of
fabricating an LCD device using an ink composition in accordance
with the present invention; and
[0042] FIGS. 9A to 9D are sectional views sequentially showing a
process of forming ink patterns using the ink composition in
accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0043] Description will now be given in detail of an ink
composition and a method of fabricating an LCD device using the
same in accordance with the preferred embodiments of the present
invention, with reference to the accompanying drawings.
[0044] An ink composition in accordance with the preferred
embodiments of the present invention may consist of 5-45% by weight
of polymer resin, 5-45% by weight of additive and 50-90% by weight
of organic solvent. Particularly, an additive, which is capable of
retaining thermal stability, is added such that the ink composition
can have superior thermal endurance and pattern-forming capability.
Also, the addition of the polymer and the additive allows an
increase in a pattern transcription rate, thereby improving yield
and process efficiency.
[0045] Here, the polymer resin in accordance with the preferred
embodiments of the present invention may include novolak resin,
acryl resin and the like which are used for the typical ink
composition.
[0046] Here, the novolak resin may be a polymer which is compounded
by reacting aromatic alcohol, such as meta cresol, para cresol,
2,3,5-trimethylphenol, 2,3-xylene, 3,5-xylene and the like with
formaldehyde or paraporeumaldehide. Also, the acryl resin may be
one obtained by polymerizing kareuboksilsan unsaturated, aromatic
monomers, acrylic monomers.
[0047] The polymer resin may preferably have a molecular weight of
2000-100000, more preferably, 2000-45000.
[0048] Preferably, 5-45% by weight of the polymer resin, more
preferably, 7-12.5% by weight of the polymer resin may be contained
with respect to the total 100% by weight of the composition. Within
the range, the polymer resin can serve as a pattern supporter and
increase a pattern transcription rate, thus enhancing yield and
improving process efficiency.
[0049] Also, the additive in accordance with the preferred
embodiments of the present invention may serve to control the
thermal stability of the ink composition. Examples of the additive
may include pentaerythritol, metyl gallate, propyl gallate, lauryl
gallate, octylgallate, metol, tyramine hydrochloride,
1-(3-hydroxyphenyl)piperazine, 4-bromo-2-(5-isoxazolyl)phenol,
4-(imidazole-1-yl)phenol, apigenin,
2-(4,5-dihydro-1H-imidazole-2-yl)phenol,
3-(4,5-dihydro-1H-imidazole-2-yl)phenol,
4-(4,5-dihydro-1H-imidazole-2-yl)phenol,
4-nitro-2-(1H-pyrazole-3-yl)phenol,
2-(2-hydroxyphenyl)-1H-benzimidazole,
4-(4-methyl-4,5-dihydro-1H-imidazole-2-yl)phenol,
1-amino-2-naphthol hydrochloride, 2,4-diamino phenol
dihydrochloride, 2-acetamidophenol, 2-amino-3-nitrophenol,
2-amino-4-chloro-5-nitrophenol, 2-amino-5-nitrophenol,
3-amino-2-naphthol, 3-methoxytyramine hydrochloride,
4,7-dimethoxy-1,10-phenanthroline, 4-amino-1-naphthol
hydrochloride, 4-amino-3-chlorophenol hydrochloride, 4-aminophenol
hydrochloride, 4-tritylphenol, 8-amino-2-naphthol, biochanin A,
chloranil, pentaBromo-phenol, quercetin dihydrate, fisetin,
1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,
tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,
octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,
2,5-bis(1,1-dimethylpropyl)-1,4-benzenediol,
1,1,3-tris-(2-methyl-4-hydroxy-5-tert-butylphenyl)butane,
triethyleneglycol-bis(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate,
2,2-methylenebis(4-methyl-6-(1-methylcyclohexyl)-phenol),
tris(2,4-di-tert-butylphenyl)phosphate and the like.
[0050] Here, preferably, 5-45% by weight of the additive may be
contained in the ink composition of the present invention, more
preferably, 7-12.5% by weight of the additive may be contained in
the ink composition. Within the range, the linewidths and line
intervals of patterns are allowed to be constantly maintained, so
as to improve accuracy of the patterns, which are to be desirably
formed on a substrate, resulting in enhancement of yield and
process efficiency.
[0051] The organic solvent in accordance with the preferred
embodiments of the present invention may be an easily soluble
solvent, which is useable, if necessary, in addition to the polymer
resin and the additive.
[0052] For instance, the organic solvent may be a single solvent or
a mixture of two or more types of solvents selected from the
following solvents, examples of which may include acrylonitrile,
acetonitrile, glycerol, dimethyl sulfoxide, nitromethane,
dimethylformamide, phenol, N-methylpyrrolidone, pyridine
perfluorotributylamine, perfluorodecalin, 2-butanone, methylene
carbonate, types of alcohols including methanol, ethanol, ethylene
glycol, triethyleneglycol, tetraethylene glycol, propylene glycol,
propylene ethylene glycol, diethylene glycol, butanediol, benzyl
alcohol, hexyl alcohol, allyl alcohol and the like, types of ethers
including propylene carbonate, tetrahydrofuran, methoxy benzene,
1,4-dioxane, 1-methoxy-2-propanol, dibutyl ether, diphenyl ether
and the like, types of esters including ethyl acetate, methyl
acetate, propyl acetate, butyl actate, ethylpropion, ethylester,
butyl ester, methyl-2-hydroxyisobutyrate, 2-methoxy-1-methylethyl
ester, 2-methoxyethanol acetate, 2-ethoxyethanol acetate and the
like, type of ethylene glycol alkyl ether acetates including
ethylene glycol methyl ether acetate, ethylene glycol ethyl ether
acetate and the like, types of ethylene glycol alkyl ether
propionates including ethylene glycol methyl ether propionate,
ethylene glycol ethyl ether propionate and the like, types of
ethylene glycol monoalkyl ethers including ethylene glycol methyl
ether, ethylene glycol ethyl ether and the like, types of
diethylene glycol alkyl ethers including diethylene glycol
monomethyl ether, diethylene glycol monoethyl ether, diethylene
glycol dimethyl ether, diethylene glycol methyl ethyl ether and the
like, types of propylene glycol alkyl ether acetates including
propylene glycol methyl ether acetate, propylene glycol ethyl ether
acetate, propylene glycol propyl ether acetate and the like, types
of propylene glycol alkyl ether propionates including propylene
glycol methyl ether propipnate, propylene glycol ethyl ether
propionate, propylene glycol propyl ether propionate and the like,
types propylene glycol monoalkyl ethers including propylene glycol
methyl ether, propylene glycol ethyl ether, propylene glycol propyl
ether, propylene glycol butyl ether and the like, types of
dipropylene glycol alkyl ethers including dipropylene glycol
dimethyl ether, dipropylene glycol diethyl ether and the like,
types of butylene glycol monomethyl ethers including butylene
glycol monomethyl ether, butylene glycol monoethyl ether and the
like, and types of dibutylene glycol alkyl ethers including
dibutylene glycol dimetyl ether, dibutylene glycol diethyl ether
and the like. Particularly, in order to grant an enhanced coating
performance to silicon polymer, it is advantageous for pattern
transcription to use the mixture of more then two types of the
organic solvents, other than a single solvent.
[0053] The 50-90% by weight of the organic solvent may be
preferably contained in the ink composition, more preferably,
70.about.80% by weight of the organic solvent may be contained in
the ink composition. Within the range, the organic solvent may
contribute to the process efficiency as well as to the
solubility.
[0054] The ink composition for the imprint lithography and the roll
printing of the present invention, consisting of the aforementioned
components, may further include a surfactant, an adhesive
sensitizer or visible compound.
[0055] Here, the surfactant may prevent stains of ink material and
hole marks which may occur on the silicon polymer, and ensure
better coating performance.
[0056] Examples of the surfactant may include a silicon-based
surfactant or a fluorine-based surfactant such as
perfluoroalkyloligomer, and the content of the surfactant may
occupy 0.01-3% by weight, preferably, 0.1-1.5% by weight of the
total 100% by weight of the ink composition.
[0057] Also, the adhesive sensitizer may be used for improving the
property of adhesion to a lower layer, example of which may include
a typical melanin crosslinking agent.
[0058] Examples of the melanin crosslinking agent may include a
condensation product of urea and formaldehyde, a condensation
product of melamine and formaldehyde, a type of methylol urea alkyl
ether or a type of methylol melamine alkyl ether obtained from
alcohol. For example, examples of the condensation product of urea
and formaldehyde may include monomethylol urea, dimethylol urea and
the like. An example of the condensation product of melamine and
formaldehyde may include hexamethylol melamine. Also, part of the
condensation product of the melamine and formaldehyde may also be
used as the melanin crosslinking agent. The type of methylol urea
alkyl ether may be obtained by reaction among the condensation
product of urea and formaldehyde, part or all of methylol group and
alcohol. Examples of the types of methylol urea alkyl ethers may
include monomethyl urea methyl ether, dimethyl urea methyl ether
and the like. The type of methylol melamine alkyl ether may be
obtained by reaction among the condensation product of melamine and
formaldehyde, part or all of methylol group and alcohol. Examples
of the types of methylol melamine alkyl ethers may include hexa
methylol melamine hexa methyl ether, hexa methylol melamine hexa
butyl ether and the like. A compound in a structure that hydrogen
atom of amino group of melamine is replaced with hydroxymethyl
group and methoxymethyl group, a compound in a structure that
hydrogen atom of amino group of melamine is replaced with
butoxymethyl group and methoxymethyl group and the like may also be
employed. Especially, the type of methylol melamine alkyl ether may
be preferably used.
[0059] The content of the adhesive sensitizer, if used, may
preferably be 0.01-5% by weight, more preferably, 0.5-2.5% by
weight of the total 100% by weight of the composition. Within the
range, the ink composition in accordance with the preferred
embodiments of the present invention can have superior adherence
with a lower substrate, and may serve to later protect a metal
layer, located at a lower portion of a pattern during an etching
process.
[0060] The visible compound may ensure visibility of the ink
composition by use of dye, pigment or photosensitive compound.
Also, the visible compound may improve pattern transfer capability
by being soluble in polymer resin and additionally facilitate
ensuring of adhesive force with a substrate on which patterns are
to be desirably formed.
[0061] As the visible compound, diazide-based compounds, namely,
2,3,4-trihydroxybenzophenone-1,2-napthoquinonediazide-5-sulfonate
fabricated by esterifying trihydroxybenzophenone with
2-diazo-1-naphthol-5-sulfonic acid,
2,3,4,4-tetrahydroxybenzophenone-1,2-napthoquinonediazide-5-sulfonate
fabricated by esterifying tetrahydroxybenzophenone with
2-diazo-1-naphthol-5-sulfonic acid, and the like, may be used
individually or by being mixed together.
[0062] The content of the visible compound, if used, may preferably
be 0.001-3.0% by weight, more preferably, 0.001-2.0% by weight of
the total 100% by weight of the ink composition according to the
preferred embodiments of the present invention.
[0063] The ink composition in accordance with the preferred
embodiments of the present invention having such configuration may
be applied to a pattern formation by use of an imprint lithography
and a roll printing, so as to allow fine patterns to be accurately
formed on a substrate.
[0064] Particularly, the ink composition in accordance with the
preferred embodiments of the present invention may include polymer
resin and additive both endurable even at a high temperature of
about 90.about.250.degree. C., thereby ensuring superior
transcription rate of fine patterns and allowing accurate formation
of fine patterns. Such improved properties will now be described in
detail in comparison with comparison examples (hereinafter,
referred to as `comparison`).
[0065] FIG. 2 is a table showing comparison results of ink
compositions, fabricated using different additives, from first and
second embodiments and first and second comparisons, wherein unit
is percent by weight.
[0066] As shown in FIG. 2, it is represented that for the
respective ink is compositions of the first and second embodiments
and the first and second comparisons, novolak resin, ethanol,
silicon group and hexamethylol melamine hexamethyl ether were used
respectively as polymer resin, organic solvent, surfactant and
adhesive sensitizer, for each of which metyl gallate, propyl
gallate, 2,4-dimethylphenol and rosin were used as additives.
[0067] Here, total 100% by weight of each ink composition of the
first and second embodiments and the first and second comparisons
may consist of 10.0% by weight of polymer resin, 10.0% by weight of
additive, 80.0% by weight of organic solvent, 1.0% by weight of
surfactant and 3.0% by weight of adhesive sensitizer.
[0068] By use of the fabricated ink compositions of the first and
second embodiments and the first and second comparisons, various
properties thereof were estimated by the following method.
[0069] First, each ink composition of the first and second
embodiments and the first and second comparisons was coated on
silicon polymer with no pattern, and naturally dried for 10
seconds. Fine patterns were transferred on a target substrate while
the silicon polymer rolled on a cliche. The transcription rate of
the thusly obtained patterns was then measured.
[0070] FIG. 3 is a table showing comparison results of each pattern
transcription rate of the ink compositions from the first and
second embodiments and the first and second comparisons of FIG. 2,
wherein the pattern transcription rate is represented in the range
of 0.about.100% according to whether patterns have been formed in
100 cells each having 1.times.1 mm in size.
[0071] As shown in FIG. 3, the first and second embodiments showed
98% and 97% of pattern transcription rates, respectively, whereas
the first and second comparisons showed 85% and 79% of pattern
transcription rates.
[0072] That is, it was exhibited that each ink composition of the
first and second embodiments using the additives with high thermal
resistance showed more than 97% of superior pattern transcription
rate.
[0073] In the meanwhile, in order to measure accuracy of fine
patterns formed, each ink composition of the first and second
embodiments and the first and second comparisons was coated on
silicon polymer with no pattern, and naturally dried for a preset
time. Fine patterns were transferred on the target substrate while
the silicon polymer rolled on a cliche. After the fine
patterns-transcribed substrate was thermally treated at a high
temperature of 200.degree. C. for 3 minutes, the accuracy of the
pattern formation was checked by use of an optical microscope. The
checked results can be seen in FIGS. 4 to 7.
[0074] FIGS. 4 and 5 are optical microscopic photos each showing a
thermally treated surface of a fine pattern formed by using the ink
compositions each fabricated from the first and second embodiments
according to the present invention. FIGS. 6 and 7 are optical
microscopic photos each showing a thermally treated surface of a
fine pattern formed by using the ink compositions each fabricated
from the first and second comparisons according to the present
invention.
[0075] As shown in FIGS. 4 and 5, patterns are uniformly formed
upon using each ink composition according to the first and second
embodiments of the present invention. Accordingly, no pattern
linewidth is changed before and after the thermal treatment, which
thusly exhibits superior accuracy of the pattern formation.
[0076] To the contrary, as shown in FIGS. 6 and 7, upon using each
ink composition fabricated in the first and second comparisons, a
drastic change in the pattern linewidth can be observed before and
after the thermal treatment, is which thusly exhibits inaccuracy of
the pattern formation.
[0077] The ink compositions having such properties in accordance
with the embodiments of the present invention can be used for an
imprint lithography and a roll printing, so as to allow forming of
fine patterns, which are applied to information storage, compact
sensors, photonic crystal and optical devices, micro-electro
mechanical systems, display devices and semiconductors, which will
hereinafter be described in detail through an exemplary method for
fabricating an LCD device.
[0078] FIG. 8 is a flowchart sequentially showing a method of
fabricating an LCD device using an ink composition in accordance
with the present invention, which shows a method for fabricating an
LCD device in case of forming a liquid crystal layer by a liquid
crystal dropping method. However, the present invention may not be
limited to this method, but also applicable to a method for
fabricating an LCD device in case of forming a liquid crystal layer
by a liquid crystal injection method.
[0079] The fabrication process of the LCD device may be divided
into a switching device array process of forming switching devices
on a lower array substrate, a color filter process of forming color
filters on an upper color filter substrate, and a cell process.
[0080] Through an array process, a plurality of gate lines and data
lines, which are arranged on the lower substrate to define pixel
regions, and thin film transistors (TFTs) as switching devices
connected to the gate lines and data lines are formed respectively
at the pixel regions (S101). Also, through the array process, a
pixel electrode, which is connected to the TFTs for driving a
liquid crystal layer responsive to a signal being applied via the
TFTs, is formed.
[0081] Also, a color filter layer provided with red, green and blue
sub filters is rendering colors and a common electrode are formed
on the upper substrate through the color filter process (S103).
[0082] Here, various fine patterns are formed through the array
process and the color filter process. Upon the patterns being
formed, an imprint lithography and a roll printing using the ink
compositions according to the embodiment of the present invention
may be used, which will hereinafter be described in detail with
reference to the drawings.
[0083] Meanwhile, the lower substrate and the upper substrate each
are configured as a large mother substrate. In other words, a
plurality of panel regions are formed on the large mother
substrates, and the TFT as the switching device and the color
filter layer are formed at each panel region.
[0084] FIGS. 9A to 9D are sectional views sequentially showing a
process of forming ink patterns using an ink composition in
accordance with the present invention, in which a roll printing
process is exemplarily described. However, the present invention
may not be limited to the roll printing process, but also
applicable to forming ink patterns through the imprint
lithography.
[0085] As shown in FIG. 9A, a printing plate 101 having printing
grooves 102, which substantially have the same patterns to target
ink patterns is prepared. An ink 103 containing solvent is then
provided on the printing plate 101 from an ink feeder 104.
[0086] Although not shown in detail in the drawings, a roll
printing apparatus is used for printing various ink patterns on a
target substrate, and includes the printing plate 101, the ink
feeder 104 for providing the ink 103 on the printing plate 101, and
a transfer roller provided with a transfer sheet for transferring
the ink 103 filled in the printing plate 101 onto the target
substrate.
[0087] Here, the printing plate 101 is provided with a plurality of
printing grooves 102 for forming target ink patterns on an upper
surface thereof, and each of the printing grooves 102 may
substantially have the same shape to the target ink pattern.
[0088] The ink feeder 104 then coats the ink 103 on the printing
plate 101 with a thickness of 0.5-10 .mu.m by employing an
appropriate method, for example, spin coating, roller coating, slit
coating and the like.
[0089] Here, the ink composition composing the ink 103 according to
the embodiments of the present invention may consist of 5-45% by
weight of polymer resin, 5-45% by weight of additive and 50-90% by
weight of organic solvent. Especially, 5-45% by weight of the
additive by which a thermal stability is retained is added such
that the ink composition can have excellent thermal resistance and
pattern-forming capability. The added additive can also increase a
pattern transcription rate so as to improve yield and process
efficiency.
[0090] Next, as shown in FIG. 9B, the ink 103 coated on the
printing plate 101 is filled in each printing groove 102 by using a
blade 130. That is, if the blade 130 is placed on the printing
plate 101 provided with the ink 103 and moved in one direction in a
contact state with the upper surface of the printing plate 101, the
ink 103 provided on the upper surface of the printing plate 101 is
squeezed in the proceeding direction to be filled in the printing
grooves 102. Also, the ink 103 on the upper surface of the printing
plate 101 excluding the printing grooves 102 is removed by the
blade 130. Here, a removal blade (not shown) for completely
removing the remnant ink 103 on the upper surface of the printing
plate 101 may further be provided.
[0091] As shown in FIG. 9C, a transfer roller 150 having a transfer
sheet 155 is rolled on the upper surface of the printing plate 101
filled with the ink 103. Accordingly, the ink 103 filled in the
printing grooves 102 is transferred onto the transfer sheet 155 of
the transfer roller 150.
[0092] The transfer roller 150 may be formed, for example, in a
cylindrical shape, and its outer surface is covered with the
transfer sheet 155. The transfer sheet 155 may be formed of a
material, which has an excellent adhesive property with the ink
103, for example, silicon with excellent hydrophilicity. Also, the
transfer sheet 155 may have elasticity so as to facilitate ink
transfer from the printing plate 101 and ink re-transfer onto the
target substrate.
[0093] As shown in FIG. 9D, the transfer roller 150 is then rolled
in one direction to retransfer the ink 103, which has been
transferred on the transfer sheet 155, onto the target substrate
110, thereby forming preset ink patterns 120.
[0094] Here, an interval between the transfer roller 150 and a
lower frame (not shown) may be adjustable such that the transfer
sheet 155 covering the transfer roller 150 can contact the upper
surface of the target substrate 110 while the transfer roller 150
is rotated. Here, the transfer sheet 155 of the transfer roller 150
does not have to certainly contact the upper surface of the target
substrate 110. However, a distance, which is at least as short as
the ink transferred onto the transfer sheet 155 from the printing
plate 101 can contact the upper surface of the target substrate
110, should be maintained.
[0095] Afterwards, although not shown in the drawings, it may also
be possible to conduct a photocuring process using ultraviolet, a
thermosetting process of performing a thermal treatment at a
temperature of 90-200.degree. C., or a combination of the
photocuring and the thermosetting processes. Here, the thermal
treatment is performed to evaporate solvent without pyrolyzing
solid component contained in is the ink composition. Typically, it
is preferable to minimize the concentration of the solvent through
the thermal treatment and execute the thermal treatment until an
ink layer with thickness less than 10 .mu.m is left on a
substrate.
[0096] Such a process may enhance adhesive property and chemical
resistance between the ink layer and the substrate. The
process-completed substrate is then treated with an etching
solution or gaseous plasma so as to process an exposed portion of
the substrate. Here, the non-exposed portion of the substrate is
protected by the ink layer. After the treatment of the substrate,
the ink layer is removed by an appropriate stripper, thereby
forming fine patterns on the substrate.
[0097] Afterwards, an alignment layer is printed on each of the
upper substrate and the lower substrate. The alignment layers are
aligned with each other so as to provide an anchoring force or
surface anchoring characteristics (that is, pretilt angle and
alignment direction) to liquid crystal molecules of a liquid
crystal layer interposed between the upper substrate and the lower
substrate.
[0098] In case of employing a dropping method, preset seal patterns
are formed on the color filter substrate by use of sealant and
simultaneously a liquid crystal layer is formed on the array
substrate (S105 and S106) (see FIG. 8).
[0099] In the dropping method, liquid crystal is dropped and
dispensed through a dispenser on an image display region either of
a first large mother substrate having a plurality of array
substrates or a second large mother substrate having a plurality of
color filter substrates, and the liquid crystal is uniformly
distributed all over the image display region by pressure of
attaching the first and second mother substrates, thereby forming
the liquid crystal layer.
[0100] Therefore, upon forming the liquid crystal layer on an LCD
panel through the dropping method, the seal patterns should be
formed in form of a closed is pattern covering the periphery of
each pixel region such that the liquid crystal cannot be leaked out
of the image display region.
[0101] Upon employing the dropping method, liquid crystal may be
dropped within a short time, compared to employing a vacuum
injection method, and also the liquid crystal layer can be formed
very fast even if the LCD panel becomes larger.
[0102] Also, since liquid crystal is dropped on a substrate as much
as being needed upon employing the dropping method, an increase in
fabricating cost of the LCD panel due to discard of high-priced
liquid crystal can be prevented, resulting in strengthening
competitiveness of products.
[0103] Afterwards, referring back to FIG. 8, in a state where the
upper substrate and the lower substrate on which the liquid crystal
is dropped and the sealant is coated are aligned with each other,
pressure is applied so as to attach the lower substrate and the
upper substrate by the sealant and simultaneously to render the
dropped liquid crystal distributed all over the panel (S107).
Through the process, a plurality of LCD panels having the liquid
crystal are formed on the large mother substrate (lower substrate
and upper substrate). The glass substrate is then processed and cut
into the plurality of LCD panels. Each of the LCD panels is then
inspected so as to complete the fabrication of the LCD device (S108
and S109).
[0104] The foregoing embodiments and advantages are merely
exemplary and are not to be construed as limiting the present
disclosure. The present teachings can be readily applied to other
types of apparatuses. This description is intended to be
illustrative, and not to limit the scope of the claims. Many
alternatives, modifications, and variations will be apparent to
those skilled in the art. The features, structures, methods, and
other characteristics of the exemplary is embodiments described
herein may be combined in various ways to obtain additional and/or
alternative exemplary embodiments.
[0105] As the present features may be embodied in several forms
without departing from the characteristics thereof, it should also
be understood that the above-described embodiments are not limited
by any of the details of the foregoing description, unless
otherwise specified, but rather should be construed broadly within
its scope as defined in the appended claims, and therefore all
changes and modifications that fall within the metes and bounds of
the claims, or equivalents of such metes and bounds are therefore
intended to be embraced by the appended claims.
* * * * *