U.S. patent application number 11/154579 was filed with the patent office on 2005-11-24 for radiation sensitive resin composition, cathode separator and el display device.
This patent application is currently assigned to JSR CORPORATION. Invention is credited to Nishimura, Isao, Niwa, Kazuaki, Sasaki, Hirofumi, Suzuki, Masayoshi.
Application Number | 20050260526 11/154579 |
Document ID | / |
Family ID | 18759203 |
Filed Date | 2005-11-24 |
United States Patent
Application |
20050260526 |
Kind Code |
A1 |
Nishimura, Isao ; et
al. |
November 24, 2005 |
Radiation sensitive resin composition, cathode separator and EL
display device
Abstract
A radiation sensitive resin composition for the formation of
cathode separators for EL display devices which have heat
resistance and adhesion required for cathode separators for EL
display devices and an inversely tapered shape, cathode separators
formed therefrom and an EL display device comprising the cathode
separators. The radiation sensitive resin composition for the
formation of cathode separators for EL display devices comprises
(A) an alkali soluble resin, (B) the compound represented by the
formulae (I) to (IV) and (C) a trihalomethyltriazine and/or an
onium salt, the cathode separators are formed from the radiation
sensitive resin composition and the EL display device comprises the
cathode separators formed from the radiation sensitive resin
composition.
Inventors: |
Nishimura, Isao; (Chuo-ku,
JP) ; Suzuki, Masayoshi; (Chuo-ku, JP) ;
Sasaki, Hirofumi; (Chuo-ku, JP) ; Niwa, Kazuaki;
(Chuo-ku, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
JSR CORPORATION
Chuo-ku
JP
|
Family ID: |
18759203 |
Appl. No.: |
11/154579 |
Filed: |
June 17, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11154579 |
Jun 17, 2005 |
|
|
|
09946359 |
Sep 6, 2001 |
|
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Current U.S.
Class: |
430/270.1 |
Current CPC
Class: |
Y10S 430/106 20130101;
H01L 27/3246 20130101; G03F 7/0045 20130101; Y10S 430/111 20130101;
G03F 7/038 20130101; H01L 51/5203 20130101; H01L 27/3283
20130101 |
Class at
Publication: |
430/270.1 |
International
Class: |
G03C 001/492 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 8, 2000 |
JP |
2000-273213 |
Claims
1-6. (canceled)
7. A cathode separator for EL display devices formed from a
radiation sensitive composition comprising: (A) an alkali soluble
resin; (B) at least one compound selected from the group consisting
of a compound represented by the following formula (I): 8wherein
six Rs may be the same or different and each a hydrogen atom or an
alkyl group having 1 to 6 carbon atoms, a compound represented by
the following formula (II): 9wherein Rs are defined as above, a
compound represented by the following formula (III): 10wherein Rs
are defined as above, and a compound represented by the following
formula (IV): 11wherein Rs are defined as above; (C) a
trihalomethyltriazine represented by the following formula (V):
12wherein X is a halogen atom and A is a CX.sub.3 or a group
represented by the following formula: 13B, D and E are each
independently a hydrogen atom, alkyl group, aryl group, alkoxy
group, aryloxy group, thioalkyl group or thioaryl group having 1 to
10 carbon atoms, halogen atom, cyano group, nitro group, secondary
amino group having an alkyl group with 1 to 10 carbon atoms,
carboxyl group, hydroxyl group, ketoalkyl group or ketoaryl group
having 1 to 10 carbon atoms, or alkoxycarbonyl group or
alkylcarbonyloxy group having 1 to 20 carbon atoms, and m is an
integer of 1 to 5, or an onium salt which serves as an optically
acid generating agent represented by the following formula (VI):
(A).sub.nZ.sup.+Y.sup.- (VI)wherein A is as defined hereinabove, Z
is sulfur or iodine, Y is BF.sub.4, PF.sub.6, SbF.sub.6, AsF.sub.6,
p-toluene sulfonate, trifluoromethane sulfonate or
trifluoroacetate, and n is 2 or 3, and (D) an ultraviolet light
absorber selected from the group consisting of benzotriazoles,
salicylates, substituted acrylonitriles, coumarins, flavones and
chalcones, wherein the cathode separator has a trapezoidal cross
section with a top side longer than a bottom side and an angle
formed by a straight line connecting an upper pattern edge and a
lower pattern edge and the top side of 15 to 75.degree..
8. A cathode separator for EL display devices formed from a
radiation sensitive composition comprising: (A) an alkali soluble
resin; (B) at least one compound selected from the group consisting
of a compound represented by the following formula (I): 14wherein
six Rs may be the same or different and each a hydrogen atom or an
alkyl group having 1 to 6 carbon atoms, a compound represented by
the following formula (II): 15wherein Rs are defined as above, a
compound represented by the following formula (III): 16wherein Rs
are defined as above, and a compound represented by the following
formula (IV): 17wherein Rs are defined as above; (C) a
trihalomethyltriazine represented by the following formula (V):
18wherein X is a halogen atom and A is a CX.sub.3 or a group
represented by the following formula: 19B, D and E are each
independently a hydrogen atom, alkyl group, aryl group, alkoxy
group, aryloxy group, thioalkyl group or thioaryl group having 1 to
10 carbon atoms, halogen atom, cyano group, nitro group, secondary
amino group having an alkyl group with 1 to 10 carbon atoms,
carboxyl group, hydroxyl group, ketoalkyl group or ketoaryl group
having 1 to 10 carbon atoms, or alkoxycarbonyl group or
alkylcarbonyloxy group having 1 to 20 carbon atoms, and m is an
integer of 1 to 5, or an onium salt which serves as an optically
acid generating agent represented by the following formula (VI):
(A).sub.nZ.sup.+Y.sup.- (VI)wherein A is as defined hereinabove, Z
is sulfur or iodine, Y is BF.sub.4, PF.sub.6, SbF.sub.6, AsF.sub.6,
p-toluene sulfonate, trifluoromethane sulfonate or
trifluoroacetate, and n is 2 or 3, and (D) an ultraviolet light
absorber selected from the group consisting of
2-(2-hydroxy-3,5-bis(.alpha.,.alpha.-dimethylbenzyl)p-
henyl)-2H-benzotriazole, hydroxyphenylbenzotriazole derivative,
condensate between
methyl-3-(3-t-butyl-5-(2H-benzotriazol-2-yl)-4-hydroxyphenyl)prop-
ionate and polyethylene glycol having a molecular weight of 300,
and dibenzylideneacetone, wherein the cathode separator has a
trapezoidal cross section with a top side longer than a bottom side
and an angle formed by a straight line connecting an upper pattern
edge and a lower pattern edge and the top side of 15 to 75.degree..
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a radiation sensitive resin
composition for the formation of cathode separators for EL display
devices, a cathode separator and an EL display device. More
specifically, it relates to a radiation sensitive resin composition
suitable for use as a material for the formation of cathode
separators for EL display devices, a cathode separator formed
therefrom and an EL display device.
DESCRIPTION OF THE PRIOR ART
[0002] Generally speaking, it is difficult to carry out the
micropatterning of the cathode or organic EL layer of an organic EL
device due to the low heat resistance (generally 100.degree. C. or
less), solvent resistance and moisture resistance of an organic EL
material used in an electron transfer layer and emissive layer. For
example, when photolithography used for the patterning of a thin
film is used for an organic EL device, the characteristics of the
organic EL device are deteriorated by the infiltration of a solvent
contained in a photoresist into the organic EL device, the
infiltration of a high-temperature atmosphere during the baking of
the photoresist, a photoresist developer or etchant into the
organic EL device and damage caused by plasma at the time of dry
etching.
[0003] Although patterning may be carried out using a deposition
mask, a fine pattern cannot be formed by the inclusion of a
deposited product caused by poor adhesion between the mask and a
substrate during vapor deposition, a short circuit between a
cathode and an anode made of indium tin oxide (to be abbreviated as
ITO hereinafter) caused by the damage of an organic EL layer by
contact with the mask when the substrate and the deposition mask
are closely adhered to each other forcedly, and the deflection of
the mask due to insufficient strength in the case of a striped
cathode pattern with small masking portions and large openings.
[0004] To solve the above problems, the technology disclosed by
JP-A 2-66873 (the term "JP-A" as used herein means an "unexamined
published Japanese patent application") is to pattern a photoresist
comprising a solvent which does not dissolve an organic EL material
on the organic EL device and etch a cathode using diluted sulfuric
acid. However, the organic EL material is damaged by the diluted
sulfuric acid at the time of etching.
[0005] The technology disclosed by JP-A 5-275172, JP-A 5-258859 and
JP-A 5-258860 is to form cathode separators having a tapered cross
section with a height of several to several tens of micrometers and
arranged parallel to one another on a substrate after ITO
patterning and to deposit an organic EL material and a cathode
material from a direction perpendicular to the cathode separators
and a direction diagonal to the surface of the substrate on the
substrate for patterning. That is, a method of forming a first
electrode line and an organic EL material thin film by vacuum
deposition in an oblique direction selectively by shutting out a
predetermined gas stream with high cathode separators formed at the
boundary on the substrate in order to prevent a space between
cathode separators from being polluted during deposition. However,
in this oblique deposition method, a portion where the organic EL
material is not deposited is existent in an opening between cathode
separators and the brightness of a display device becomes
unsatisfactory. JP-A 8-315981 uses cathode separator having a
overhung cross section (trapezoidal with a bottom side shorter than
a top side) to enable vacuum deposition from above and eliminate
the above defect of oblique deposition. However, generally existing
resist materials have low heat resistance and cannot retain an
inversely tapered shape due to softening during curing.
[0006] When a volatile component derived from the cathode separator
material is contained in an EL layer as an impurity, it may cause
such a problem as a reduction in the light emitting area of an EL
light emitting device or a lighting failure.
[0007] Problems to be Solved by the Invention
[0008] It is therefore an object of the present invention which has
been made in view of the above situation to provide a radiation
sensitive resin composition for the formation of cathode separators
for EL display devices which have required heat resistance and
adhesion and an inversely tapered shape.
[0009] It is another object of the present invention to provide a
cathode separator formed from the above radiation sensitive resin
composition and an EL display device comprising the cathode
separators.
[0010] Other objects and advantages of the present invention will
become apparent from the following description.
[0011] According to the present invention, firstly, the above
objects and advantages of the present invention are attained by a
radiation sensitive resin composition, which comprises:
[0012] (A) an alkali soluble resin;
[0013] (B) at least one compound selected from the group consisting
of a compound represented by the following formula (I): 1
[0014] wherein six Rs may be the same or different and each a
hydrogen atom or an alkyl group having 1 to 6 carbon atoms,
[0015] a compound represented by the following formula (II): 2
[0016] wherein Rs are defined as above,
[0017] a compound represented by the following formula (III): 3
[0018] wherein Rs are defined as above,
[0019] and a compound represented by the following formula (IV):
4
[0020] wherein Rs are defined as above; and
[0021] (C) a trihalomethyltriazine represented by the following
formula (V): 5
[0022] wherein X is a halogen atom and A is CX.sub.3 or a group
represented by the following formulas: 6
[0023] B, D and E are each independently a hydrogen atom, alkyl
group, aryl group, alkoxy group, aryloxy group, thioalkyl group or
thioaryl group having 1 to 10 carbon atoms, halogen atom, cyano
group, nitro group, secondary amino group having an alkyl group
with 1 to 10 carbon atoms, carboxyl group, hydroxyl group,
ketoalkyl group or ketoaryl group having 1 to 10 carbon atoms, or
alkoxycarbonyl group or alkylcarbonyloxy group having 1 to 20
carbon atoms, and m is an integer of 1 to 5, or an onium salt which
serves as an optically acid generating agent represented by the
following formula (VI):
(A).sub.nZ.sup.+Y.sup.- (VI)
[0024] wherein A is as defined hereinabove, Z is sulfur or iodine,
Y is BF.sub.4, PF.sub.6, SbF.sub.6, AsF.sub.6, p-toluene sulfonate,
trifluoromethane sulfonate or trifluoroacetate, and n is 2 or 3,
and which is for formation of cathode separators for EL display
devices.
[0025] Secondly, the above objects and advantages of the present
invention are attained by a cathode separator for EL display
devices, which is formed from the above radiation sensitive resin
composition.
[0026] Thirdly, the above objects and advantages of the present
invention are attained by an EL display device comprising the above
cathode separators.
[0027] The El display device of the present invention comprehends
an organic EL display device and an inorganic EL display device.
Out of these, the organic EL display device is preferred.
[0028] Each component of the radiation sensitive resin composition
of the present invention will be detailed hereinbelow.
[0029] (A) Alkali Soluble Resin
[0030] The alkali soluble resin used in the present invention is
not particularly limited if it is alkali-soluble. A novolak resin,
a homopolymer of a radical polymerizable monomer having a phenolic
hydroxyl group or carboxyl group and a copolymer of the radical
polymerizable monomer and another radical polymerizable monomer are
preferred as the alkali soluble resin.
[0031] The novolak resin is alkali-soluble and is obtained by
polycondensing a phenol, preferably a phenol containing m-cresol,
and an aldehyde. As the phenol other than m-cresol (to be simply
referred to as "phenolic monomer" hereinafter) used in the
production of the novolak resin are advantageously used phenol,
p-cresol, o-cresol, 2,3-xylenol, 2,5-xylenol, 3,5-xylenol,
2,3,5-trimethylphenol, catechol, resorcinol, hydroquinone,
methylhydroquinone, pyrogallol and phloroglucinol. These phenolic
monomers may be used alone or in combination of two or more,
preferably in combination with m-cresol.
[0032] The molar ratio of m-cresol to the phenolic monomer is
preferably 20/80 to 100/0, more preferably 30/70 to 100/0. When the
amount of m-cresol is smaller than 20 mol %, the resolution of the
obtained composition tends to deteriorate.
[0033] The phenol is polycondensed with an aldehyde such as
formaldehyde or acetaldehyde in the presence of an acid catalyst
such as oxalic acid to obtain a novolak resin of interest.
[0034] Water is generally used as a reaction medium in the
polycondensation reaction. When the phenol used in the
polycondensation reaction does not dissolved in an aqueous solution
of an aldehyde and a heterogeneous system is formed from the
beginning of the reaction, a hydrophilic organic solvent may be
used as the reaction medium. Examples of the solvent used in this
case include alcohols such as methanol, ethanol and butanol, and
cyclic ethers such as tetrahydrofuran and dioxane. The amount of
the reaction medium is preferably 20 to 400 parts by weight based
on 100 parts by weight of the total of the reaction raw
materials.
[0035] The polycondensation reaction temperature can be suitably
adjusted according to the reactivity of the reaction raw materials
but it is preferably 10 to 200.degree. C. After the end of the
polycondensation reaction, the novolak resin can be recovered by
elevating the temperature to 130 to 230.degree. C. to remove an
unreacted raw material, acid catalyst and reaction medium existent
in the system and distilling off a volatile component under reduced
pressure.
[0036] The novolak resin used in the present invention has a weight
average molecular weight in terms of standard polystyrene (to be
referred to as "Mw" hereinafter) of preferably 2,000 to 30,000,
particularly preferably 3,500 to 20,000. When Mw is more than
30,000, the developability of the composition of the present
invention may deteriorate and when Mw is less than 2,000, film
formation properties may worsen. In the radiation sensitive resin
composition of the present invention, the above novolak resins may
be used alone or in combination of two or more.
[0037] Preferred examples of the radical polymerizable monomer
having a phenolic hydroxyl group or carboxyl group used to
synthesize a homopolymer of a radical polymerizable monomer having
a phenolic hydroxyl group or carboxyl group and a copolymer of the
radical polymerizable monomer and another radical polymerizable
monomer include o-hydroxystyrene, m-hydroxystyrene,
p-hydroxystyrene and alkyl, alkoxy, halogen, haloalkyl, nitro,
cyano, amide, ester and carboxy substituted products thereof;
polyhydroxyvinyl phenols such as vinylhydroquinone,
5-vinylpyrogallol, 6-vinylpyrogallol and 1-vinylphloroglucinol;
o-vinylbenzoic acid, m-vinylbenzoic acid, p-vinylbenzoic acid, and
alkyl, alkoxy, halogen, nitro, cyano, amide and ester substituted
products thereof; methacrylic acid, acrylic acid, and a-position
haloalkyl, alkoxy, halogen, nitro and cyano substituted products
thereof; divalent unsaturated carboxylic acids such as maleic acid,
maleic anhydride, fumaric acid, fumaric anhydride, citraconic acid,
mesaconic acid, itaconic acid, 1,4-cyclohexenedicarboxylic acid,
and methyl, ethyl, propyl, i-propyl, n-butyl, sec-butyl, ter-butyl,
phenyl, o-, m- and p-toluyl half-ester and half-amide thereof.
[0038] Out of these, o-hydroxystyrene, m-hydroxystyrene,
p-hydroxystyrene, and alkyl and alkoxy substituted products thereof
are preferred from the viewpoints of sensitivity at the time of
patterning, resolution, film retention after development, thermal
deformation resistance, solvent resistance, adhesion to the base
and solution keeping stability.
[0039] They may be used alone or in combination of two or more.
[0040] Examples of the another radical polymerizable monomer
include styrene, .alpha.-position, o-position, m-position and
p-position alkyl, alkoxy, halogen, haloalkyl, nitro, cyano, amide
and ester substituted products of styrene; diolefins such as
butadiene, isoprene and chloroprene; methyl, ethyl, n-propyl,
i-propyl, n-butyl, sec-butyl, ter-butyl, pentyl, neopentyl,
isoamylhexyl, cyclohexyl, adamantyl, allyl, propargyl, phenyl,
naphthyl, anthracenyl, anthraquinonyl, piperonyl, salicyl,
cyclohexyl, benzyl, phenethyl, cresyl, glycidyl,
1,1,1-trifluoroethyl, perfluoroethyl, perfluoro-n-propyl,
perfluoro-i-propyl, triphenylmethyl,
tricyclo[5.2.1.0.sup.2.6]decan-8-yl (commonly called
"dicyclopentanyl" in this technical field), cumyl,
3-(N,N-dimethylamino)propyl, 3-(N,N-dimethylamino)ethyl, furyl and
furfuryl esterified products of methacrylic acid and acrylic acid;
anilide, amide, N,N-dimethyl, N,N-diethyl, N,N-dipropyl,
N,N-diisopropyl, anthranylamide, acrylonitrile, acrolein,
methacrylonitrile, vinyl chloride, vinylidene chloride, vinyl
fluoride, vinylidene fluoride, N-vinylpyrrolidone, vinylpyridine,
vinyl acetate, N-phenylmaleinimide, N-(4-hydroxyphenyl)maleinimide,
N-methacryloylphthalimide and N-acryloylphthalimide of methacrylic
acid and acrylic acid. They may be used alone or in combination of
two or more.
[0041] Out of these, styrene, and .alpha.-position, o-position,
m-position and p-position alkyl, alkoxy, halogen and haloalkyl
substituted products of styrene; butadiene and isoprene; and
methyl, ethyl, n-propyl, N-butyl, glycidyl and dicyclopentanyl
esterified products of methacrylic acid and acrylic acid are
particularly preferred from the viewpoints of sensitivity at the
time of patterning, resolution, film retention after development,
thermal deformation resistance, solvent resistance, adhesion to the
base and solution keeping stability.
[0042] When a copolymer of a radical polymerizable monomer having a
phenolic hydroxyl group and another radical polymerizable monomer
is used as the alkali soluble resin, the amount of the another
radical polymerizable monomer is preferably 30 wt % or less,
particularly preferably 5 to 20 wt % based on the total weight of
the radical polymerizable monomer having a phenolic hydroxyl group
and the another radical polymerizable monomer.
[0043] When a copolymer of a radical polymerizable monomer having a
carboxyl group and another radical polymerizable monomer is used as
the alkali soluble resin, the amount of the another radical
polymerizable monomer is preferably 90 wt % or less, particularly
preferably 10 to 80 wt % based on the total weight of the radical
polymerizable monomer having a carboxyl group and the another
radical polymerizable monomer.
[0044] When the ratio of the another radical polymerizable monomer
to the radical polymerizable monomer having a phenolic hydroxyl
group or carboxyl group is outside the above range, alkali
development may become difficult.
[0045] Generally known radical polymerization initiators may be
used as the polymerization initiator used in the production of a
homopolymer of a radical polymerizable monomer having a phenolic
hydroxyl group or carboxyl group or a copolymer of the radical
polymerizable monomer and another radical polymerizable monomer, as
exemplified by azo compounds such as 2,2'-azobisisobutyronitrile,
2,2'-azobis-(2,4-dimethylvaleronitri- le) and
2,2'-azobis-(4-methoxy-2,4-dimethylvaleronitrile; organic peroxides
such as benzoyl peroxide, lauroyl peroxide, t-butyl peroxypivalate
and 1,1'-bis-(t-butylperoxy)cyclohexane; and hydrogen peroxide.
When a peroxide is used as the radical polymerization initiator,
the peroxide may be used in conjunction with a reducer as a redox
initiator.
[0046] Examples of the solvent used in the production of a
homopolymer of a radical polymerizable monomer having a phenolic
hydroxyl group or carboxyl group or a copolymer of the radical
polymerizable monomer and another radical polymerizable monomer
include alcohols such as methanol and ethanol; ethers such as
tetrahydrofuran; glycol ethers such as ethylene glycol monomethyl
ether and ethylene glycol monoethyl ether; ethylene glycol alkyl
ether acetates such as methyl cellosolve acetate and ethyl
cellosolve acetate; diethylene glycols such as diethylene glycol
monomethyl ether, diethylene glycol monoethyl ether, diethylene
glycol dimethyl ether, diethylene glycol diethyl ether and
diethylene glycol ethylmethyl ether; propylene glycol monoalkyl
ethers such as propylene glycol monomethyl ether, propylene glycol
monoethyl ether, propylene glycol monopropyl ether and propylene
glycol monobutyl ether; propylene glycol alkyl ether acetates such
as propylene glycol methyl ether acetate, propylene glycol ethyl
ether acetate, propylene glycol propyl ether acetate and propylene
glycol butyl ether acetate; propylene glycol alkyl ether
propionates such as propylene glycol methyl ether propionate,
propylene glycol ethyl ether propionate, propylene glycol propyl
ether propionate and propylene glycol butyl ether propionate;
aromatic hydrocarbons such as toluene and xylene; ketones such as
methyl ethyl ketone, cyclohexanone and
4-hydroxy-4-methyl-2-pentanone; and esters such as methyl acetate,
ethyl acetate, propyl acetate, butyl acetate, ethyl
2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl
2-hydroxy-2-methylpropionate, methyl hydroxyacetate, ethyl
hydroxyacetate, butyl hydroxyacetate, methyl lactate, ethyl
lactate, propyl lactate, butyl lactate, methyl 3-hydroxypropionate,
ethyl 3-hydroxypropionate, propyl 3-hydroxypropionate, butyl
3-hydroxypropionate, methyl 2-hydroxy-3-methylbutanoate, methyl
methoxyacetate, ethyl methoxyacetate, propyl methoxyacetate, butyl
methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, propyl
ethoxyacetate, butyl ethoxyacetate, methyl propoxyacetate, ethyl
propoxyacetate, propyl propoxyacetate, butyl propoxyacetate, methyl
butoxyacetate, ethyl butoxyacetate, propyl butoxyacetate, butyl
butoxyacetate, methyl 2-methoxypropionate, ethyl
2-methoxypropionate, propyl 2-methoxypropionate, butyl
2-methoxypropionate, methyl 2-ethoxypropionate, ethyl
2-ethoxypropionate, propyl 2-ethoxypropionate, butyl
2-ethoxypropionate, methyl 2-butoxypropionate, ethyl
2-butoxypropionate, propyl 2-butoxypropionate, butyl
2-butoxypropionate, methyl 3-methoxypropionate, ethyl
3-methoxypropionate, propyl 3-methoxypropionate, butyl
3-methoxypropionate, methyl 3-ethoxypropionate, ethyl
3-ethoxypropionate, propyl 3-ethoxypropionate, butyl
3-ethoxypropionate, methyl 3-propoxypropionate, ethyl
3-propoxypropionate, propyl 3-propoxypropionate, butyl
3-propoxypropionate, methyl 3-butoxypropionate, ethyl
3-butoxypropionate, propyl 3-butoxypropionate and butyl
3-butoxypropionate.
[0047] The amount of the solvent is preferably 20 to 1,000 parts by
weight based on 100 parts by weight of the total of the reaction
raw materials.
[0048] The weight average molecular weight in terms of polystyrene
of a homopolymer of a radical polymerizable monomer having a
phenolic hydroxyl group or carboxyl group or a copolymer of the
radical polymerizable monomer and another radical polymerizable
monomer is preferably 2,000 to 100,000, more preferably 3,000 to
50,000, particularly preferably 5,000 to 30,000.
[0049] When the average molecular weight is smaller than 2,000, the
pattern shape, resolution, developability and heat resistance are
apt to deteriorate and when the average molecular weight is larger
than 100,000, developability, particularly sensitivity often tends
to degrade.
[0050] The above homopolymers of a radical polymerizable monomer
having a phenolic hydroxyl group or carboxyl group and the above
copolymers of the radical polymerizable monomer and another radical
polymerizable monomer may be used alone or in combination of two or
more.
[0051] Before polymerization, a protective group may be introduced
into the carboxyl group or phenolic hydroxyl group and removed
after polymerization to provide alkali solubility so as to
synthesize an alkali soluble resin. Further, visible light
transmission and softening point may be changed by
hydrogenation.
[0052] As described above, a novolak resin, a homopolymer of a
radical polymerizable monomer having a phenolic hydroxyl group or
carboxyl group and a copolymer of the radical polymerizable monomer
and another radical polymerizable monomer are preferably used as
the alkali soluble resin (A) used in the present invention. Part of
the alkali soluble resin (A) may be substituted with another
phenolic compound.
[0053] The another phenolic compound used in the present invention
is a phenolic compound having a molecular weight of 1,000 or less.
When the molecular weight of the phenolic compound is larger than
1,000,resolution degrades. Examples of the low-molecular weight
phenolic compound include compounds having the following
structures. 7
[0054] In the above formulas, R.sup.2's may be the same or
different and each a hydrogen atom or methyl group, and a, b, c, d,
k, l, m and n are each an integer of 0 to 3, with the proviso that
a+b+c+d.gtoreq.2.
[0055] When part of the alkali soluble resin (A) is substituted
with another phenolic compound, the amount of the another phenolic
compound is preferably 80 wt % or less, more preferably 50 wt % or
less based on the total weight of the alkali soluble resin (A) and
the another phenolic compound. When the amount of the another
phenolic compound is larger than 80 wt %, a coating film may not be
formed.
[0056] (B) Compound Represented by the Formula (I) to (IV)
[0057] Examples of the compounds represented by the above formulae
(I) to (IV) include hexamethoxymethylolmelamine,
hexabutoxymethylolmelamine, tetramethoxymethylolbenzoquanamine,
tetramethoxymethylolguanamine, tetramethoxymethylolglycoluril.
These compounds may be used alone or in admixture. And these
compounds may be used as pure compound or as a mixture with an
oligomer of such compound having a weight average molecular weight
of 1,500 or less.
[0058] Out of these compounds, commercially available Cymel 300,
301, 303, 370, 325, 327, 701, 266, 267, 238, 1141, 272, 202, 1156,
1158, 1123, 1170, 1174, UFR65 and 300 (of Mitsui Cyanamid Co.,
Ltd.), Nikalack Mx-750, -032, -706, -708, -40 and -31, Nikalack
Ms-11, and Nikalack Mw-30 (of Sanwa Chemical Co., Ltd.) are
preferred.
[0059] The amount of the compound is preferably 1 to 100 parts by
weight, more preferably 5 to 50 parts by weight based on 100 parts
by weight of the alkali soluble resin (A). When the amount is
smaller than 1 part by weight, film retention after development may
lower and heat resistance and solvent resistance may
deteriorate.
[0060] (C) Trihalomethyltriazine Represented by the Formula (V) or
Onium Salt Serving as Optically Acid Generating Agent Represented
by the Formula (VI)
[0061] Examples of the trihalomethyltriazine represented by the
above formula (V) include
[0062] 2,4,6-tris(trichloromethyl)-s-triazine,
[0063] 2-phenyl-4,6-bis(trichloromethyl)-s-triazine,
[0064] 2-(4-chlorophenyl)-4,6-bis(trichloromethyl)-s-triazine,
[0065] 2-(3-chlorophenyl)-4,6-bis(trichloromethyl)-s-triazine,
[0066] 2-(2-chlorophenyl)-4,6-bis(trichloromethyl)-s-triazine,
[0067] 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine,
[0068] 2-(3-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine,
[0069] 2-(2-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine,
[0070]
2-(4-methylthiophenyl)-4,6-bis(trichloromethyl)-s-triazine,
[0071]
2-(3-methylthiophenyl)-4,6-bis(trichloromethyl)-s-triazine,
[0072]
2-(2-methylthiophenyl)-4,6-bis(trichloromethyl)-s-triazine,
[0073]
2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine,
[0074]
2-(3-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine,
[0075]
2-(2-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine,
[0076]
2-(4-methoxy-.beta.-styryl)-4,6-bis(trichloromethyl)-s-triazine,
[0077]
2-(3-methoxy-.beta.-styryl)-4,6-bis(trichloromethyl)-s-triazine,
[0078]
2-(2-methoxy-.beta.-styryl)-4,6-bis(trichloromethyl)-s-triazine,
[0079]
2-(3,4,5-trimethoxy-.beta.-styryl)-4,6-bis(trichloromethyl)-s-triaz-
ine,
[0080]
2-(4-methylthio-.beta.-styryl)-4,6-bis(trichloromethyl)-s-triazine,
[0081]
2-(3-methylthio-.beta.-styryl)-4,6-bis(trichloromethyl)-s-triazine
and
[0082]
2-(2-methylthio-.beta.-styryl)-4,6-bis(trichloromethyl)-s-triazine.
[0083] Examples of the onium salt represented by the above formula
(VI) include diaryl iodonium salts such as diphenyliodonium
tetrafluoroborate, diphenyliodonium hexafluorophosphonate,
diphenyliodonium hexafluoroarsenate, diphenyliodonium
trifluoromethane sulfonate, diphenyliodonium trifluoroacetate,
diphenylindonium-p-toluene sulfonate,
[0084] 4-methoxyphenylphenyliodonium tetrafluoroborate,
[0085] 4-methoxyphenylphenyliodonium hexafluorophosphonate,
[0086] 4-methoxyphenylphenyliodonium hexafluoroarsenate,
[0087] 4-methoxyphenylphenyliodonium trifluoromethane
sulfonate,
[0088] 4-methoxyphenylphenyliodonium trifluoroacetate,
[0089] 4-methoxyphenylphenyliodonium-p-toluene sulfonate,
[0090] bis(4-ter-butylphenyl)iodonium tetrafluoroborate,
[0091] bis(4-ter-butylphenyl)iodonium hexafluorophosphonate,
[0092] bis(4-ter-butylphenyl)iodonium hexafluoroarsenate,
[0093] bis(4-ter-butylphenyl)iodoniumtrifluoromethane
sulfonate,
[0094] bis(4-ter-butylphenyl)iodonium trifluoroacetate and
[0095] bis(4-ter-butylphenyl)iodonium-p-toluene sulfonate; and
[0096] triaryl sulfonium salts such as triphenylsulfonium
tetrafluoroborate, triphenylsulfonium hexafluorophosphonate,
triphenylsulfonium hexafluoroarsenate, triphenylsulfonium
trifluoromethane sulfonate, triphenylsulfonium trifluoroacetate,
triphenylsulfonium-p-toluene sulfonate,
[0097] 4-methoxyphenyldiphenylsulfonium tetrafluoroborate,
[0098] 4-methoxyphenyldiphenylsulfonium hexafluorophosphonate,
[0099] 4-methoxyphenyldiphenylsulfonium hexafluoroarsenate,
[0100] 4-methoxyphenyldiphenylsulfonium trifluoromethane sulfonate,
4-methoxyphenyldiphenylsulfonium trifluoroacetate,
[0101] 4-methoxyphenyldiphenylsulfonium-p-toluene sulfonate,
[0102] 4-phenylthiophenyldiphenyl tetrafluoroborate,
[0103] 4-phenylthiophenyldiphenyl hexafluorophosphonate,
[0104] 4-phenylthiophenyldiphenyl hexafluoroarsenate,
[0105] 4-phenylthiophenyldiphenyl trifluoromethane sulfonate,
[0106] 4-phenylthiophenyldiphenyl trifluoroacetate and
[0107] 4-phenylthiophenyldiphenyl-p-toluene sulfonate.
[0108] Out of these compounds,
[0109] 2-(3-chlorophenyl)-4,6-bis(trichloromethyl)-s-triazine,
[0110] 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine,
[0111]
2-(4-methylthiophenyl)-4,6-bis(trichloromethyl)-s-triazine,
[0112]
2-(4-methoxy-.beta.-styryl)-4,6-bis(trichloromethyl)-s-triazine,
[0113] 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine,
diphenyliodonium trifluoroacetate, diphenylindonium
trifluoromethane sulfonate,
[0114] 4-methoxyphenylphenyliodonium trifluoromethane
sulfonate,
[0115] 4-methoxyphenylphenyliodonium trifluoroacetate,
triphenylsulfonium trifluoromethane sulfonate, triphenylsulfonium
trifluoroacetate,
[0116] 4-methoxyphenyldiphenylsulfonium trifluoromethane sulfonate,
4-methoxyphenyldiphenylsulfonium trifluoroacetate,
4-phenylthiophenyldiphenyl trifluoromethane sulfonate and
4-phenylthiophenyldiphenyl trifluoroacetate are preferred.
[0117] The amount of the compound represented by the above formula
(V) or (VI) is preferably 0.001 to 10 parts by weight, more
preferably 0.01 to 5 parts by weight based on 100 parts by weight
of the alkali soluble resin (A). When the amount is smaller than
0.001 part by weight, the heat resistance and solvent resistance of
the cathode separators may lower. When the amount is larger than 10
parts by weight, the control of the pattern shape after development
may become difficult.
[0118] The compound represented by the formula (V) or (VI) may be
used in conjunction with a suitable sensitizer. Examples of the
sensitizer include coumarins having a substituent at least one
position of the 3-position and 7-position, flavones,
dibenzalacetones, dibenzalcyclohexanes, chalcones, xanthenes,
thioxanthenes and porphylins and acridines. The amount of the
ultraviolet light absorbing compound is preferably 20 parts or less
by weight, more preferably 10 parts or less by weight based on 100
parts by weight of the alkali soluble resin (A). When the amount is
larger than 20 parts by weight, the sensitizer tends to provide a
filter effect, thereby making it difficult for radiation to reach
the substrate.
[0119] Components other than the above components may be contained
in the composition of the present invention as required in limits
not prejudicial to the object of the present invention.
[0120] The other components include an ultraviolet light absorber,
compound containing two or more epoxy groups in the molecule,
surfactant, adhesion aid, keeping stabilizer and anti-foaming
agent.
[0121] The above ultraviolet light absorber may be added mainly to
obtain a good inversely tapered shape. The ultraviolet light
absorbing compound used in the present invention absorbs light
having a wavelength of less than 400 nm, particularly 365 nm,
rarely absorbs visible light and is soluble in solvents to be
described hereinafter. Examples of the ultraviolet light absorber
include benzotriazoles, salicylates, benzophenones, substituted
acrylonitriles, xanthenes, coumarins, flavones and chalcones. More
specifically, Tinubin 234 (2-(2-hydroxy-3,5-bis(.alph-
a.,.alpha.-dimethylbenzyl)phenyl)-2H-benzotriazole), Tinubin 571
(hydroxyphenylbenzotriazole derivative), Tinubin 1130 (condensate
between
methyl-3-(3-t-butyl-5-(2H-benzotriazol-2-yl)-4-hydroxyphenyl)propionate
and polyethylene glycol (molecular weight of 300)) (of Chiba
Specialty Chemicals Co., Ltd.),
1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3- ,5-dione and
dibenzylideneacetone are commercially available. The amount of the
ultraviolet light absorber is preferably 20 parts or less by
weight, more preferably 10 parts or less by weight based on 100
parts by weight of the alkali soluble resin (A). When the
ultraviolet light absorber is added in an amount of more than 20
parts by weight, sensitivity is liable to lower.
[0122] The compound containing two or more epoxy groups in the
molecule may be blended mainly to improve heat resistance and
adhesion. Examples of the compound containing two or more epoxy
groups in the molecule include bisphenol A epoxy resins such as
Epicoat 1001, 1002, 1003, 1004, 1007, 1009, 1010 and 828 (of Yuka
Shell Epoxy Co., Ltd.); bisphenol F epoxy resins such as Epicoat
807 (of Yuka Shell Epoxy Co., Ltd.); phenol novolak epoxy resins
such as Epicoat 152 and 154 (of Yuka Shell Epoxy Co., Ltd.) and
EPPN201 and 202 (of Nippon Kayaku Co., Ltd.); cresol novolak type
epoxy resins such as EOCN-102, 103S, 104S, 1020, 1025 and 1027 (of
Nippon Kayaku Co., Ltd.) and Epicoat 180S75 (of Yuka Shell Epoxy
Co., Ltd.); cyclic aliphatic epoxy resins such as CY-175, 177 and
179 (of CIBA-GEIGY A.G), ERL-4234, 4299, 4221 and 4206 (of U.C.C.
Co., Ltd.), Showdyne 509 (of Showa Denko K.K.), Araldyte CY-182,
192 and 184 (of CIBA-GEIGY A.G.), Epichlon 200 and 400 (of
Dainippon Ink & Chemicals, Inc.), Epicoat 871 and 872 (of Yuka
Shell Epoxy Co., Ltd.), and ED-5661 and 5662 (of Celaneas Coating
Co., Ltd.); and aliphatic polyglycidyl ethers such as Epolite 100MF
(of Kyoeisha Kagaku Co., Ltd.) and Epiol TMP (of NOF Corporation).
Out of these, bisphenol A epoxy resins, bisphenol F epoxy resins,
phenol novolak epoxy resins, cresol novolak epoxy resins and
aliphatic polyglycidyl ethers are preferred.
[0123] A compound such as a glycidyl ether of bisphenol A or
bisphenol F may also be suitably used. The amount of the compound
containing two or more epoxy groups in the molecule is preferably 1
to 100 parts by weight, more preferably 5 to 50 parts by weight
based on 100 parts by weight of the alkali soluble resin (A).
[0124] When a copolymer having a structural unit derived from a
monomer containing an epoxy group such as glycidyl (meth)acrylate
is used as the alkali soluble resin (A), it can be said that the
component (A) is a "compound containing two or more epoxy groups in
the molecule" but differs from the compound in that it is required
to have alkali solubility and to be a relatively high molecular
weight polymer.
[0125] The above surfactant may be blended to improve striation and
the developability of a radiation exposed portion after the
formation of a dried coating film. Examples of the surfactant
include nonionic surfactants such as polyoxyethylene alkyl ethers
including polyoxyethylene lauryl ether, polyoxyethylene stearyl
ether and polyxoyethylene oleyl ether, polyoxyethylene aryl ethers
including polyoxyethylene octylphenyl ether and polyoxyethylene
nonylphenyl ether, and polyethylene glycol dialkyl esters including
polyethylene glycol dilaurate and polyethylene glycol distearate;
fluorine-based surfactants such as F Top EF301, 303 and 352 (of
Shin Akita Kasei Co., Ltd.), Megafac F171, 172 and 173 (of
Dainippon Ink & Chemicals, Inc.), Florade FC430 and 431 (of
Sumitomo 3M Limited), Asahi Guard AG710, Surflon S-382, SC-101,
102, 103, 104, 105 and 106 (of Asahi Glass Co., Ltd.);
organosiloxane polymer KP341 (of Shin-Etsu Chemical Co., Ltd.), and
acrylic acid-based or methacrylic acid-based (co)polymer Polyflow
No. 57 and 95 (of Kyoeisha Kagaku Co., Ltd.).
[0126] The amount of the surfactant is preferably 2 parts or less
by weight, more preferably 1 part or less by weight based on 100
parts by weight of the total solid content of the composition.
[0127] Preparation of Radiation Sensitive Resin Composition
[0128] The radiation sensitive resin composition of the present
invention is prepared by uniformly mixing together (A) an alkali
soluble resin, (B) the compound represented by the above formulae
(I) to (IV) and (C) a compound represented by the above formula (V)
or (VI) and optionally used other additives. The radiation
sensitive resin composition of the present invention is
advantageously used as a solution prepared by dissolving the above
components in a suitable solvent. For example, the radiation
sensitive resin composition in a solution state can be prepared by
mixing together (A) the alkali soluble resin, (B) the compound
represented by the above formulae (I) to (IV) and (C) compound
represented by the above formula (V) or (VI) and optionally added
other compounding ingredients in a predetermined ratio.
[0129] The solvent used to prepare the radiation sensitive resin
composition of the present invention uniformly dissolves (A) the
alkali soluble resin, (B) the compound represented by the above
formulas (I) to (IV) and (C) compound represented by the above
formula (V) or (VI) and optionally added other additives and does
not react with these components.
[0130] Examples of the solvent include alcohols such as methanol
and ethanol; ethers such as tetrahydrofuran; glycol ethers such as
ethylene glycol monomethyl ether and ethylene glycol monoethyl
ether; ethylene glycol alkyl ether acetates such as methyl
cellosolve acetate and ethyl cellosolve acetate; diethylene glycols
such as diethylene glycol monomethyl ether, diethylene glycol
monoethyl ether and diethylene glycol dimethyl ether; propylene
glycol monoalkyl ethers such as propylene glycol methyl ether,
propylene glycol ethyl ether, propylene glycol propyl ether and
propylene glycol butyl ether; propylene glycol alkyl ether acetates
such as propylene glycol methyl ether acetate, propylene glycol
ethyl ether acetate, propylene glycol propyl ether acetate and
propylene glycol butyl ether acetate; propylene glycol alkyl ether
propionates such as propylene glycol methyl ether propionate,
propylene glycol ethyl ether propionate, propylene glycol propyl
ether propionate and propylene glycol butyl ether propionate;
aromatic hydrocarbons such as toluene and xylene; ketones such as
methyl ethyl ketone, cyclohexanone and
4-hydroxy-4-methyl-2-pentanone; and esters such as methyl acetate,
ethyl acetate, propyl acetate, butyl acetate, ethyl
2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl
2-hydroxy-2-methylpropionate, methyl hydroxyacetate, ethyl
hydroxyacetate, butyl hydroxyacetate, methyl lactate, ethyl
lactate, propyl lactate, butyl lactate, methyl 3-hydroxypropionate,
ethyl 3-hydroxypropionate, propyl 3-hydroxypropionate, methyl
3-butoxypropionate, ethyl 3-butoxypropionate, propyl
3-butoxypropionate and butyl 3-butoxypropionate.
[0131] Out of these solvents, glycol ethers, ethylene glycol alkyl
ether acetates, propylene glycol alkyl ether acetates, esters and
diethylene glycols are preferred from the viewpoints of solubility,
reactivity with the above components and the formation ease of a
coating film.
[0132] A high-boiling solvent may be used in conjunction with the
above solvent. Examples of the high-boiling solvent include
N-methylformamide, N,N-dimethylformamide, N-methylformanilide,
N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone,
dimethyl sulfoxide, benzylethyl ether, dihexyl ether,
acetonylacetone, isophorone, caproic acid, caprylic acid,
1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl
benzoate, diethyl oxalate, diethyl maleate, .gamma.-butyrolactone,
ethylene carbonate, propylene carbonate and phenyl cellosolve
acetate.
[0133] The radiation sensitive resin composition of the present
invention is prepared by using the above solvent and can be
prepared to a suitable solid content according to its use
purpose.
[0134] The solid content may be, for example, 10 to 50 wt %,
preferably 20 to 40 wt %.
[0135] The composition solution prepared as described above may be
filtered with a Millipore filter having a pore diameter of 0.5
.mu.m before use.
[0136] Method of Forming Cathode Separator
[0137] The method of forming the cathode separator of the present
invention from the radiation sensitive resin composition of the
present invention will be detailed hereinbelow.
[0138] A coating film is formed by applying a solution of the
radiation sensitive resin composition of the present invention to
the surface of a substrate and heating to remove the solvent. Spray
coating, roll coating and rotational coating may be used to apply
the solution of the radiation sensitive resin composition to the
surface of the substrate.
[0139] This coating film is then prebaked. The solvent is
volatilized by heating to obtain a coating film having no
fluidity.
[0140] The heating conditions which differ according to the type
and amount of each component are preferably selected from a wide
temperature range of 60 to 120.degree. C. and a wide time range of
10 to 600 sec.
[0141] The obtained coating film of the radiation sensitive resin
composition is exposed to radiation on the surface thereof through
a mask having a predetermined pattern shape. The amount of energy
of the radiation, that is, the type of the radiation is suitably
determined according to desired resolution and wavelength to which
the radiation sensitive compound is sensitive. For example,
ultraviolet radiation such as g-line (wavelength of 436 nm), h-line
(405 nm) and i-line (365 nm), deep ultraviolet ray such as excimer
(KrF, ArF) laser light, X-ray such as synchrotron radiation, and
charged corpuscular beams such as electron beams may be used, out
of which g-line and i-line are preferred.
[0142] After exposure to radiation, PEB (post-exposure baking) is
carried out before alkali development. The PEB temperature is
preferably 200.degree. C. or less and the PEB time is preferably
0.1 to 10 minutes. After PEB, the coating film is developed with a
developer to remove unrequired portions.
[0143] As the developer may be used an aqueous solution of an
alkali such as an inorganic alkali exemplified by sodium hydroxide,
potassium hydroxide, sodium carbonate, sodium silicate, sodium
metasilicate and ammonia water; primary amine exemplified by
ethylamine and n-propylamine; secondary amine exemplified by
diethylamine and di-n-propylamine; tertiary amine exemplified by
triethylamine, methyldiethylamine and N-methylpyrrolidone; alcohol
amine exemplified by dimethylethanolamine and triethanolamine;
quaternary ammonium salt exemplified by tetramethylammonium
hydroxide, tetraethylammonium hydroxide and choline; or cyclic
amine exemplified by pyrrole, piperidine,
1,8-diazabicyclo[5.4.0]-7-undecene and
1,5-diazabicyclo[4.3.0]-5-nonane.
[0144] An aqueous solution prepared by adding a water-soluble
organic solvent such as methanol or ethanol, or a surfactant to the
above alkali aqueous solution in an appropriate amount may also be
used.
[0145] The development time is, for example, 30 to 180 sec. and
puddle development and dipping development may be used. After
development, the developed coating film is washed with running
water for 30 to 90 sec. and dried with compressed air or compressed
nitrogen to remove water on the substrate to form a coating film
pattern.
[0146] Subsequently, the coating film is heated at a predetermined
temperature, for example, 150 to 250.degree. C. by a heating unit
such as a hot plate or oven for a predetermined time, for example,
5 to 30 minutes on the hot plate or 30 to 90 minutes in the oven to
obtain a crosslinked film pattern.
[0147] The cathode separator of the present invention preferably
has a trapezoidal cross section in an irradiation direction with
the top side longer than the bottom side (inversely tapered shape),
more preferably an angle formed between a straight line connecting
the upper pattern edge and the lower pattern edge and the top side
of 15 to 750. Since the cross section of the cathode separator is
inversely tapered, the deposition of an organic EL material from
above and not an oblique direction is made possible. That is, the
organic EL material is deposited from above so that it is uniformly
adhered to an opening between adjacent cathode separators, thereby
making it possible to secure sufficient brightness for a display
device. When a cathode material is deposited from above, it can be
prevented from being adhered to a lower portion of the inversely
tapered shape, thereby making it possible to ensure insulation
between cathodes.
[0148] The amount of a volatile component generated from the
cathode separator of the present invention by heating at 25 to
200.degree. C. is preferably 10 wt % or less, more preferably 5 wt
% or less, much more preferably 2 wt % or less, particularly
preferably 1 wt % or less.
[0149] By reducing the amount of the volatile component to the
above range, the intrusion of impurities into the EL layer can be
prevented, thereby making it possible to eliminate the occurrence
of a lighting failure of the EL display device and a reduction in
the brightness of emission.
[0150] The amount of the volatile component can be evaluated by TDS
(Thermal Desorption Spectroscopy) measurement or the like.
[0151] Production of Organic EL Display Device
[0152] The organic EL display device of the present invention
comprises cathode separators formed as described above. The organic
EL display device of the present invention is produced as follows,
for example.
[0153] A transparent electrode such as ITO is formed on a glass
substrate by sputtering, and a positive photoresist is applied to
the transparent electrode and prebaked. The resist is exposed
through a mask and developed to form a resist pattern, the ITO film
is etched by a hydrochloric acid-based etchant such as ferric
chloride, and the resist film is removed to obtain a transparent
electrode pattern, for example, a striped pattern. Thereafter, the
radiation sensitive resin composition of the present invention is
applied to the surface of the substrate having the transparent
electrode pattern to form inversely tapered cathode separators as
described above. Subsequently, a hole transfer layer, organic EL
layer and cathode layer are formed by vapor deposition
sequentially. The hole transfer layer is made from a
phthalocyanine-based material such as CuPc or H.sub.2Pc, or an
aromatic amine. The organic EL material is prepared by doping a
base material such as Alq.sub.3 or BeBq.sub.3 with quinacridone or
coumarin. The cathode material is, for example, Mg--Al, Al--Li,
Al--Li.sub.2O or Al--LiF.
[0154] An organic EL display device is then produced by sealing a
hollow-structured stainless steel can and the above substrate with
a sealing material such as an epoxy resin and assembling them into
a module.
EXAMPLES
[0155] The following synthetic examples, examples and comparative
examples are provided for the purpose of further illustrating the
present invention but are in no way to be taken as limiting.
Synthesis Example 1 (Synthesis of Resin A-1)
[0156] 176 g (0.1 mol) of t-butoxystyrene and 5.8 g (0.04 mol) of
azobisbutyronitrile were placed in a flask equipped with a cooling
tube, stirrer and thermometer, and 250 ml of propylene glycol
monomethyl ether was added and dissolved to carry out
polymerization at 75.degree. C. for 4 hours. 50 g of a 5 wt %
aqueous sulfuric acid solution was mixed with the obtained poly
t-butoxystyrene solution to carry out a hydrolytic reaction at
100.degree. C. for 3 hours. The reaction product was then washed
with 1,000 ml of deionized water three times, and 500 ml of
propylene glycol monomethyl ether acetate was added to carry out
solvent substitution to obtain a solution containing an alkali
soluble resin (A-1) (polyhydroxystyrene) having an Mw of
24,000.
Synthesis Example 2 (Synthesis of Resin A-2)
[0157] 57 g (0.6 mol) of meta-cresol, 38 g (0.4 mol) of
para-cresol, 75.5 g (0.93 mol of formaldehyde) of a 37 wt %
formaldehyde aqueous solution, 0.63 g (0.005 mol) of oxalic
dianhydride and 264 g of methylisobutyl ketone were charged into a
flask equipped with a cooling tube, stirrer and thermometer, and
the flask was immersed in an oil bath to carry out polycondensation
for 4 hours under agitation while the reaction solution was
refluxed. After the temperature of the oil bath was raised to
150.degree. C. over 3 hours, the inside pressure of the flask was
reduced to 30 to 50 mmHg to remove a volatile component and the
molten resin A was recovered by cooling to room temperature. This
resin was dissolved in ethyl acetate to a resin content of 30%, and
methanol and water were added in amounts 1.3 times and 0.9 time the
weight of the solution, respectively, stirred and left. Then, a
lower layer out of two separated layers was taken out, concentrated
and dried to obtain an alkali soluble resin (A-2) (novolak resin)
having a Mw of 8,000.
Synthesis Example 3
[0158] 5 parts by weight of 2,2'-azobis(2,4-dimethylvaleronitrile)
and 200 parts by weight of diethylene glycol ethyl methyl ether
were charged into a flask equipped with a cooling tube and stirrer.
Subsequently, 25 parts by weight of styrene, 40 parts by weight of
methacrylic acid and 30 parts by weight of
tricycyclo[5.2.1.0.sup.2.6]decan-8-yl methacrylate were added, the
inside of the flask was substituted by nitrogen, and 5 parts by
weight of 1,3-butadiene was added and stirred gently. The
temperature of the resulting solution was raised to 70.degree. C.
and maintained at that temperature for 4 hours to obtain a polymer
solution containing an alkali soluble resin (A-3) having a Mw of
12,000. The solid content of the obtained polymer solution was
33.5%.
Synthesis Example 4
[0159] 7 parts by weight of 2,2'-azobis(2,4-dimethylvaleronitrile)
and 200 parts by weight of diethylene glycol ethyl methyl ether
were charged into a flask equipped with a cooling tube and stirrer.
Subsequently, 10 parts by weight of styrene, 20 parts by weight of
methacrylic acid, 45 parts by weight of glycidyl methacrylate and
25 parts by weight of tricycyclo[5.2.1.0.sup.2.6]decan-8-yl
methacrylate were added, the inside of the flask was substituted by
nitrogen, and the resulting solution was stirred gently. The
temperature of the resulting solution was raised to 70.degree. C.
and maintained at that temperature for 5 hours to obtain a polymer
solution containing an alkali soluble resin (A-4) having a Mw of
10,000. The solid content of the obtained polymer solution was
33.5%.
Example 1
[0160] Preparation of Radiation Sensitive Resin Composition
[0161] The solution (corresponding to 100 parts by weight (solid
content) of the resin (A-1)) containing the alkali soluble resin
(A-1) obtained in Synthesis Example 1, 20 parts by weight of Cymel
300 (of Mitsui Cyanamid Co., Ltd.) as the component (B), 0.2 part
by weight of
2-(4-methoxy-.beta.-styryl)-4,6-bis(trichloromethyl)-s-triazine as
the component (C), 10 parts by weight of Epicoat 152 as a compound
containing two or more epoxy groups in the molecule (of Yuka Shell
Epoxy Co., Ltd.) and 0.04 part by weight of Megafac F172 (of
Dainippon Ink & Chemicals, Inc) as a surfactant were mixed
together and dissolved in ethyl 3-ethoxypropionate to a solid
content of 35 wt %, and the resulting solution was filtered with a
Millipore filter having a pore diameter of 0.5 .mu.m to prepare a
radiation sensitive resin composition solution (S-1).
[0162] (I) Formation of Cathode Separators
[0163] The above composition solution (S-1) was applied to the
surface of a glass substrate by a spinner and prebaked on a hot
plate at 110.degree. C. for 3 minutes to form a 5 .mu.m thick
coating film.
[0164] The above obtained coating film was exposed to ultraviolet
radiation having an intensity of 10 mW/cm.sup.2 at 365 nm through a
pattern mask having 10 .mu.m.times.10 .mu.m openings for 10
seconds. This exposure was carried out in an oxygen atmosphere (in
the air). Thereafter, this exposed coating film was developed with
a 2.38 wt % aqueous solution of tetramethylammonium hydroxide at
25.degree. C. for 90 seconds and washed with running pure water for
1 minutes. The formed cathode separators were heated in an oven at
220.degree. C. for 60 minutes to be cured to obtain 4.5 .mu.m thick
cathode separators.
[0165] (II) Evaluation of Shape of Cathode Separator
[0166] The upper tapered angle of the sectional shape of the
cathode separator obtained in (I) above (angle formed by a straight
line connecting the upper pattern edge and the lower pattern edge
and the top side of the trapezoidal cross section) is shown in
Table 1. When this angle is 20 to 80.degree., it can be said that
the cathode separator is satisfactory. When a cathode separator has
a normally tapered cross section with an angle larger than
80.degree., or is rectangular with an angle of 90.degree. or more,
the cathode separator is not accepted.
[0167] (III) Evaluation of Heat Resistance
[0168] The cathode separators formed in (I) above were heated in an
oven at 250.degree. C. for 60 minutes. The dimensional change rate
of film thickness is shown in Table 1. When the dimensional change
rate before and after heating is within .+-.5%, it can be said that
heat resistant dimensional stability is satisfactory.
[0169] (IV) Evaluation of Volatile Component
[0170] The observation of a volatile component of the cathode
separators obtained in (I) above was evaluated by TDS measurement
(EMD-WA1000S of Denshi Kagaku Co., Ltd.). The measurement was
carried out from 25.degree. C. to 200.degree. C. at a temperature
elevation rate of 1.degree. C./s. The results are shown in Table 1.
As for the evaluation results, the amount of the volatile component
generated is expressed by wt % by changing the cathode separator
material to a substrate size of 10 mm.times.10 mm.times.4.5
.mu.m.
Example 2
[0171] A composition solution (S-2) was prepared and evaluated in
the same manner as in Example 1 except that 100 parts by weight of
the alkali soluble resin (A-2) was used as the component (A). The
results are shown in Table 1.
Example 3
[0172] A composition solution (S-3) was prepared and evaluated in
the same manner as in Example 1 except that the solution containing
an alkali soluble resin (A-3) (corresponding to 100 parts by weight
(solid content) of the resin (A-3)) was used as the component (A).
The results are shown in Table 1.
Example 4
[0173] A composition solution (S-4) was prepared and evaluated in
the same manner as in Example 1 except that the solution containing
an alkali soluble resin (A-4) (corresponding to 100 parts by weight
(solid content) of the resin (A-4)) was used as the component (A).
The results are shown in Table 1.
Example 5
[0174] A composition solution (S-5) was prepared and evaluated in
the same manner as in Example 1 except that a mixture of the
solution containing an alkali soluble resin (A-1) (corresponding to
80 parts by weight (solid content) of the resin (A-1)) and 20 parts
by weight of bisphenol A were used as the component (A). The
results are shown in Table 1.
Example 6
[0175] A composition solution (S-6) was prepared and evaluated in
the same manner as in Example 1 except that a mixture of 80 parts
by weight of the alkali soluble resin (A-2) and 20 parts by weight
of bisphenol A was used as the component (A). The results are shown
in Table 1.
Example 7
[0176] A composition solution (S-7) was prepared and evaluated in
the same manner as in Example 1 except that 2 parts by weight of
1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadien-3,5-dione was
added as an ultraviolet light absorber. The results are shown in
Table 1.
Example 8
[0177] A composition solution (S-8) was prepared and evaluated in
the same manner as in Example 2 except that 2 parts by weight of
1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadien-3,5-dione was
added as an ultraviolet light absorber. The results are shown in
Table 1.
Example 9
[0178] A composition solution (S-9) was prepared and evaluated in
the same manner as in Example 1 except that 20 parts by weight of
Cymel 1174 (of Mitsui Cyanamid Co., Ltd.) was used as the component
(B) instead of 20 parts by weight of Cymel 300. The results are
shown in Table 1.
1 TABLE 1 tapered heat resistance volatile component angle (%) (%)
Ex. 1 55 -4 1.3 Ex. 2 50 -5 1.6 Ex. 3 50 -3 0.9 Ex. 4 50 -4 0.8 Ex.
5 45 -4 1.3 Ex. 6 45 -5 1.6 Ex. 7 35 -4 1.3 Ex. 8 35 -5 1.6 Ex. 9
50 -5 2.0 Ex.: Example
[0179] As described above, according to the present invention,
there is provided a radiation sensitive resin composition which is
capable of easily forming cathode separators having excellent
performance such as an inversely tapered shape, heat resistance and
low volatility.
[0180] Highly reliable cathode separators are obtained from the
above radiation sensitive resin composition.
* * * * *