WO2010067906A1

WO2010067906A1 - Composition for patterning on thermostable transparent insulator thin film and patterning method of thin film

Info

Publication number: WO2010067906A1
Application number: PCT/KR2008/007246
Authority: WO
Inventors: Ki Hwan Ahn
Original assignee: Apm Inc.
Priority date: 2008-12-08
Filing date: 2008-12-08
Publication date: 2010-06-17

Abstract

Disclosed herein is a composition for patterning a thermostable transparent insulator thin film, including: a first oligomer having a weight average molecular weight of 500 to 10,000, the first oligomer being obtained by hydrolyzing and polymerizing silane represented by the Formula R-CH₂CH₂CH₂Si(OR')₃ (R is a monovalent substituent having at least one ethenyl group, and R' is a monovalent substituent of four carbon atoms or less); a photoinitiator generating a free radical using the irradiation of ultraviolet rays having a wavelength of 365 nm or more; and at least one of a monomer and a second oligomer having two or more unsaturated bonds in one molecule thereof. The composition is advantageous in that the hardness of the thin film can be improved by adding a monomer or oligomer having two or more unsaturated bonds to the composition as a crosslinker, the sensitivity of the composition to ultraviolet rays and the curing rate of the composition can be further improved, a photoinitiator can be widely used regardless of the kind thereof by improving the sensitivity of the photoinitiator included in the composition to ultraviolet rays, and the patterning process can be performed even by ultraviolet rays having low energy.

Description

COMPOSITION FOR PATTERNING ON THERMOSTABLE TRANSPARENT INSULATOR THIN FILM AND PATTERNING

METHOD OF THIN FILM

Technical Field

[1] The present invention relates to a composition for patterning a thermostable transparent insulator thin film, the composition being used to manufacture electronic devices or display devices, and a method of patterning a thin film. More particularly, the present invention relates to a composition for patterning a thermostable transparent insulator thin film, the composition being able to be used to form a pattern on a thin film without using photoresist because it can be cured by ultraviolet irradiation and can be developed by an aqueous alkali solution, and to a method of patterning a thin film using the composition. Background Art

[2] Regardless of display devices, semiconductor devices, printed circuit boards, micro- machines and the like, a process of forming a transparent insulation film on a substrate of an electronic device is being widely used.

[3] The film is generally formed by coating, molding, chemical vapor deposition, physical vapor deposition or the like.

[4] As a composition for forming a film by coating, an organic polymer, such as a polyimide resin or a polyacrylic resin, and an inorganic polymer, such as a polysiloxane resin, may be used.

[5] In particular, a siloxane polymer having a siloxane bond (-0-Si-O-) of organic solvent solubility is attracting considerable attention as a raw material of a transparent insulation film for a glass substrate because it has excellent flatness and smoothness, is thermostable at a temperature of 300⁰C or more, does not incur an electrical loss, and is not colored in a visible range due to its transparency.

[6] Such a transparent insulation film needs a patterning process for forming conductor wires by forming grooves on a scale of μm or by perforating it.

[7] When the transparent insulation film is made of an organic polymer, the transparent insulation film can be easily patterned using photolithography including the processes of applying a UV-sensitive resin on the transparent insulation film, exposing the applied UV-sensitive resin and developing the exposed UV-sensitive resin.

[8] In contrast, when the transparent insulation film is made of an inorganic polymer (for example, a siloxane polymer), the transparent insulation film may be patterned by applying photoresist on the transparent insulation film (siloxane polymer film), drying the applied photoresist to form a photoresist film, patterning the photoresist film, and then etching the transparent insulation film using the patterned photoresist film as a photomask.

[9] Concretely, the photoresist film is exposed by irradiating it with near-ultraviolet rays, such as i-rays, g-rays or the like, through the photomask having a pattern to be formed, and then the exposed photoresist film is developed using an organic solvent or a weak alkali solution to pattern the photoresist film, and then the transparent insulation film (siloxane polymer film) is plasma-irradiated or etched to be patterned.

[10] However, this method of patterning a transparent insulation film is problematic in that the etching process is complicated, and in that there are high costs in supplying and disposing photoresists or etchants.

[11] Further, this method of patterning a transparent insulation film is problematic in that the characteristics of the transparent insulation film is deteriorated because the plasma or etchant used to remove the photoresist after etching can damage the transparent insulation film.

[12] In order to solve the above problems occurring when the photoresist is used, attempts to solve the problems using a process of photosensitizing the siloxane polymer film and then directly patterning the photosensitized siloxane polymer film have been made.

[13] JP-A-60-049647, JP-A-61-20030, JP-A-11-302382, JP- A-55- 127023, JP-

T-2003-010603, and the like disclose methods of forming a photosensitive siloxane thin film.

[14] In the above methods, electron rays, X-rays or far-ultraviolet rays having high energy are used for patterning. However, these methods are problematic in that it is impossible to apply them to most of the electronic device manufacture processes using near- ultraviolet rays as a light source.

[15] Hence, Korean Registered Patent No. 07-69232, filed by the present applicant, discloses a photosensitive composition allowing a siloxane polymer thin film to be patterned even by near-ultraviolet rays, such as i-rays, g-rays or the like. Here, the photosensitive composition must include a photoinitiator having a benzoyl group because a general photoinitiator barely has sensitivity to ultraviolet rays of 365 nm or more and thus cannot be used.

[16] However, this photosensitive composition is problematic in that the kind of a photoinitiator must be limited as above in the preparation process thereof.

[17] Further, this photosensitive composition is also problematic in that process costs are increased due to the use of ultraviolet rays having high energy because the siloxane polymer thin film can be patterned only when ultraviolet energy is maintained at 2000 mJ/cm² or more. Disclosure of Invention

Technical Problem

[18] Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a composition for patterning a thin film, by which the patterning of the thin film can be performed by near-ultraviolet irradiation without forming a photoresist film and etching the thin film, by which the hardness of the thin film can be improved by adding a monomer or oligomer having two or more unsaturated bonds to the composition as a crosslinker, and the sensitivity of which to ultraviolet rays and the curing rate of which are further improved by allowing free radicals generated from a photoinitiator included in the composition to increase the density of the crosslinker.

[19] Another object of the present invention is to allow a photoinitiator to be widely used by adding a monomer or oligomer having two or more unsaturated bonds to the composition to further improve the sensitivity of the composition to ultraviolet rays and the curing rate of the composition.

[20] Still another object of the present invention is to enable the thin film to be patterned even by ultraviolet rays having low energy base on the activation of a crosslinking process. Technical Solution

[21] In order to accomplish the above objects, an aspect of the present invention provides a composition for patterning a thermostable transparent insulator thin film, including: a first oligomer having a weight average molecular weight of 500 to 10,000, the first oligomer being obtained by hydrolyzing and polymerizing silane represented by the Formula R-CH₂CH₂CH₂Si(OR')₃ (R is a monovalent substituent having at least one ethenyl group, and R' is a monovalent substituent of four carbon atoms or less); a photoinitiator generating a free radical using the irradiation of ultraviolet rays having a wavelength of 365 nm or more; and at least one of a monomer and a second oligomer having two or more unsaturated bonds in one molecule thereof.

[22] Here, the R further may have a methacryloxy group.

[23] Further, the monomer or the second oligomer may be at least one selected from among vinyl ether, acrylate, and vinyl acrylate.

[24] Another aspect of the present invention provides a method of patterning a thermostable transparent thin film, including the steps of: hydrolyzing and polymerizing silane using an organic solvent to obtain a first oligomer having a weight average molecular weight of 500 to 10,000; adding a photoinitiator to the first oligomer in a weight ratio of 1:0.01 ~ 1:20; adding a monomer or a second oligomer having two or more unsaturated bonds in one molecule thereof to obtain a composition; applying the composition onto a substrate and then drying the applied composition to form a film; irradiating the film with ultraviolet rays having a wavelength of 365 nm to expose the film; and dissolving an unexposed portion of the exposed film using an aqueous weak alkali solution or an organic solvent.

Advantageous Effects

[25] As described above, according to the present invention, process costs can be reduced by simplifying a process of patterning a siloxane polymer film without applying, drying and etching photoresist, the process of patterning a siloxane polymer film is environment-friendly because a waste etchant is not required to recover, and the siloxane polymer film is not damaged.

[26] Further, according to the present invention, a photosensitive siloxane film, which has excellent flatness and smoothness, is thermostable, does not incur an electrical loss and is not colored in a visible range due to its transparency, can be obtained because a patterning process can be easily and directly performed by the irradiation of near- ultraviolet rays, such as i-rays, g-rays or the like, which are not a high energy light source.

[27] Furthermore, according to the present invention, the hardness of the thin film can be improved by adding a monomer or oligomer having two or more unsaturated bonds to the composition as a crosslinker, the sensitivity of the composition to ultraviolet rays and the curing rate of the composition can be further improved, a photoinitiator can be widely used regardless of the kind thereof by improving the sensitivity of the photoinitiator included in the composition to ultraviolet rays, and the patterning process can be performed even by ultraviolet rays having low energy.

[28]

Best Mode for Carrying out the Invention

[29] Hereinafter, preferred embodiments of the present invention will be described in detail.

[30] A composition for patterning a thin film according to the present invention includes: a first oligomer having a weight average molecular weight of 500 to 10,000, the first oligomer being obtained by hydrolyzing and polymerizing silane represented by the Formula R-CH₂CH₂CH₂Si(OR'^ (R is a monovalent substituent having at least one ethenyl group, and R' is a monovalent substituent of four carbon atoms or less); a photoinitiator generating a free radical using the irradiation of ultraviolet rays having a wavelength of 365 nm or more; and at least one of a monomer and a second oligomer having two or more unsaturated bonds in one molecule thereof.

[31] Further, a method of patterning a thin film according to the present invention includes the steps of: hydrolyzing and polymerizing silane using an organic solvent to obtain a first oligomer having a weight average molecular weight of 500 to 10,000; adding a photoinitiator to the first oligomer in a weight ratio of 1:0.01 ~ 1:20; adding a monomer or a second oligomer having two or more unsaturated bonds in one molecule thereof to obtain a composition; applying the composition onto a substrate and then drying the applied composition at a temperature of 15O⁰C or less to form a film; irradiating the film with ultraviolet rays having a wavelength of 365 nm to expose the film; and dissolving an unexposed portion of the exposed film using a weak aqueous alkali solution or an organic solvent.

[32] In the silane, R is a monovalent substituent having at least one ethenyl group

(-CH=CH-). Concretely, examples of R may include a vinyl group (CH₂=CH-), an allyl group (CH₂=CH-CH₂-), an acryloxy group (CH₂=CHCOO-), a methacryloxy (CH₂ =C(CH₃)COO-) and the like, but are not limited thereto. Particularly, considering the transparency and flexibility of a film, it is preferred that R be a methacryloxy group.

[33] Here, when the carbon number of the monovalent substituent R is more than 4, it is difficult to hydrolyze and polymerize silane due to steric hindrance. Therefore, it is preferred that the carbon number thereof be 4 or less.

[34] Further, in the silane, R' is a monovalent substituent of three carbon atoms or less

[35] Three R's included in one silane molecule may overlap with each other and may be selected in consideration of the reactivity and solubility of silane to a solvent.

[36] Here, when the carbon number of the monovalent substituent R' is more than 4, the hydrolysis and polymerization of silane monomers are retarded. Therefore, it is preferred that the carbon number thereof be 3 or less. Examples of R' may include a methyl group, an ethyl group and an acetoxy group.

[37] The trifunctional silane monomers may be independently used, but may be used after they are mixed with other hydrolysable silane compounds and then the mixture is hy- drolyzed and polymerized into oligomers.

[38] Examples of the silane compounds that can be copolymerized and hydrolyzed with the trifunctional silane monomers may include tetramethoxy silane, tetraethoxy silane, tetraacetoxy silane, tetraisocyanate silane, tetraxy (acetoxy) silane, trimethoxy silane, triethoxy silane, methyl trimethoxy silane, methyl triethoxy silane, methyl triacetoxy silane, methyl triisocyanate silane, methyl tris (acetoxy) silane, 3-aminopropyl trimethoxy silane, 3-aminopropyl triethoxy silane, 3-glycidoxypropyl trimethoxy silane, phenyl trimethoxy silane, phenyl triethoxy silane, phenyl triacetoxy silane, phenyl triisocyanate silane, phenyl tris (acetoxy) silane, dimethyl dimethoxy silane, dimethyl diethoxy silane, dimethyl diacetoxy silane, dimethyl methoxyacetoxy silane, dimethyl diisocyanate silane, dimethyl methoxyisocyanate silane, dimethyl bis (acetoxy) silane, methylphenyl dimethoxy silane, diphenyl dimethoxy silane, and the like. [39] These silane compounds may be used independently or may be used in the form of combinations of two or more.

[40] Further, instead of the silane compounds, compounds containing boron (B), phosphorus (P), aluminum (Al), titanium (Ti), zirconium (Zr) and the like excluding silicon (Si) may be used.

[41] The hydrolysis and polymerization of the trifunctional silane monomers, if necessary, may be conducted by diluting the trifunctinal silane monomers with any solvent selected from among ethanol, 2-propanol, acetone and butyl acetate, adding water and an acidic or alkaline catalyst to the diluted trifunctional silane monomers, the acidic or alkaline catalyst being selected from among hydrochloric acid, acetic acid, nitric acid, ammonia, triethylamine, cyclohexylamine and tetramethyl ammonium hydroxide, and then stirring the reactants.

[42] The kind and amount of the solvent or the acidic or alkaline catalyst that is used may be optionally selected without limitation.

[43] The hydrolysis and polymerization of the trifunctional silane monomers may be conducted at a low temperature of 2O⁰C or less, but can be accelerated by heating or reflux. The reaction time is changed depending on the kind and concentration of the trifunctional silane monomers or the reaction temperature, but it takes 15 minutes ~ 30 days to obtain an oligomer having a molecular weight of 500 ~ 10,000. However, the reaction time is not limited thereto.

[44] When the weight average molecular weight of the oligomer obtained by poly- ermizing the trifunctional silane monomers is less than 500, it is difficult to form a film. In contrast, when the weight average molecular weight thereof is more than 10,000, the solubility of the oligomer is decreased, and, particularly, the solution rate of the oligomer in a developer is remarkably decreased.

[45] It is possible to form a pattern because the oligomers are independently polymerized and cured by ultraviolet irradiation. However, in order to practically improve the sensitivity of the oligomer to ultraviolet rays, it is preferred that a photoinitiator be added to the composition.

[46] That is, the photoinitiator is mixed with the composition such that the free radical polymerization of compounds can be initiated by the irradiation of ultraviolet rays having a wavelength of 365 nm or more.

[47] Examples of the photoinitiator may include benzyl, benzoin isopropyl ether, benzoin isobutyl ether, 2,2'-bis(2-chlorophenyl)-4,5,4',5'-tetraphenyl- 1 ,2'-biimidzole, lO-butyl-2-chloroacridone, diphenyl(2,4,6-trimethylbenzoyl)-phosphineoxide, phos- phineoxidephenyl bis(2,4,6-trimethylbenzoyl), 2-chlorothioxanthene-9-one, 2-isopropylthioxanthene-9-one, 4,4-bis(dimethylamino)benzophenone, bis(etha-5-2,4-cyclopentadiene-l-yl)bis[2,6-difluoro-3(l-H-pyrrol-l-yl)phenyl]titaniu m, l,2-octanedionel[4-(phenylthio)phenyl], 2-(O-benzoyloxime), tris(4-dimethylaminophenyl)methane, 4,4-bis(diethylamino)benzophenone, 2-methyl-l-((methylthio)phenyl)-2-morpholinopropane-l-one),(S)-2-benzyl-2-dimethy lamino-l,l-(4-morpholinophenyl)butane-l-one, and the like.

[48] The photoinitiator is added in an amount of 0.01 ~ 50 parts by weight, preferably 0.5

- 15 parts by weight based on the solid content of the trifunctional oligomer.

[49] Further, in addition to the essential components, water, an organic solvent, a pH adjuster such as an organic amine salt or the like, a catalyst for reaction promotion such as an organic ammonium compound, a titanium-tin compound or the like, a surfactant, an antifoamer, an adhesion promoter such as a silane coupling agent or the like may be added to the composition. Further, an alkoxy silane-based surfactant or an alkoxy silane-based adhesion promoter may be used after it is copolymerized with the silane compound that is a raw material.

[50] After the photoinitiator is added to the composition, a monomer or a second oligomer having two or more unsaturated bonds in one molecule thereof is further added thereto. Examples of the monomer or the second oligomer may include: vinyl ethers, such as allyl vinyl ether, 1,4-butanediol di vinyl ether, nonanediol di vinyl ether, cyclo- hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, triethyleneglycol divinyl ether, trimethylolpropane trivinyl ether, pentaerythritol trivinyl ether, and the like; acrylates, such as hexanediol diacrylate, hexanediolethoxylated diacrylate, bu- tanediol diacrylate, nonanediol diacrylate, hydroxypivalic acid neopentylglycol diacrylate, neopentylglycol diacrylate, neopentylglycolfluoxylated diacrylate, tripropy- leneglycol diacrylate, dipropyleneglycol diacrylate, bisphenol- A-fluoxylated-ethoxylated diacrylate, tricyclodecanedimethanol diacrylate, tetraethyleneglycol diacrylate, polyethyleneglycol diacrylate, bisphenol-A-ethoxylated diacrylate, trimethylolpropane triacrylate, trimethylolpropaneethoxylated triacrylate, trimethylolpropanefluoxylated triacrylate, glycerinefluoxylated triacrylate, pentaerythritol triacrylate, pentaerythritolethoxylated triacrylate, pentaerythrito- lethoxylated tetraacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, hexanediol dimethacrylate, butanediol dimethacrylate, ethyleneglycol dimethacrylate, diethyleneglycol dimethacrylate, triethyleneglycol dimethacrylate, bisphenol- A-ethoxylated dimethacrylate, bisphenol-A-fluoxylated-ethoxylated dimethacrylate, propyleneglycol dimethacrylate, polyethyleneglycol dimethacrylate, trimethylolpropane trimethacrylate, and the like; and vinyl acrylates, such as 2-(2-vinyloxyethoxy)ethyl acrylate, 2-(2-vinyloxyethoxy)ethyl methacrylate, and the like.

[51] However, the above mentioned examples of vinyl ethers, acrylates and vinyl acrylates may be more increased.

[52] Since the added monomer or second oligomer serves as a crosslinker in the composition, the hardness of a film to be formed is increased, and the crosslink density of the monomer or second oligomer is greatly improved by the free radicals of the pho- toinitiator, so that the sensitivity of the composition to ultraviolet rays becomes better and thus the curing rate of the composition is increased, with the result that a general photoinitiator can be used as this photoinitiator without comparing the sensitivities of photoinitiators to ulatraviolet rays with each other in the selection of photoinitiators. Further, the composition can be easily crosslinked even by the irradiation of ultraviolet rays having low energy.

[53] Here, the order of mixing a first oligomer, a photoinitiator and a monomer or second oligomer having two or more unsaturated bonds in one molecule thereof with each other may not be particularly determined.

[54] The composition prepared in this way is applied on a substrate, such as a glass substrate or the like, and then dried to form a photosensitive thin film. In this case, the drying of the composition applied on the substrate is generally performed using a hot plate for 1 - 60 minutes. Further, it is preferred that the drying of the composition be performed at a temperature of 15O⁰C or less. When the drying temperature of the composition is more than 15O⁰C, the composition is crosslinked by heat even when it is not irradiated with ultraviolet rays, and thus the composition is difficult to dissolve in a developer. Practically, however, the drying temperature thereof is not necessarily limited to 15O⁰C or less. It is more preferrable that the drying temperature thereof range from room temperature to 12O⁰C. However, the drying temperature thereof may be changed depending on the thickness and shape of a film.

[55] In order to form a pattern on the photosensitive thin film, first, the photosensitive thin film is exposed by irradiating it with ultraviolet rays having a wavelength of 365 nm or more through a mask. In this case, the exposed portion of the photosensitive thin film is rapidly polymerized under the influence of the photoinitiator and thus crosslinked, and does not dissolve in an aqueous weak alkali solution or an organic solvent. In contrast, since the unexposed portion of the photosensitive thin film is not polymerized, it dissolves in an aqueous weak alkali solution or an organic solvent.

[56] Therefore, when the exposed photosensitive thin film is treated with an aqueous weak alkali solution or an organic solvent, only the unexposed portion thereof is dissolved and thus removed, thus developing a desired pattern. In this case, 2.38 wt% of a tetramethylammonium hydroxide solution that is maintained at room temperature may be used as the aqueous weak alkali solution or the organic solvent.

[57] The film formed in this way may be directly used as a transparent insulation film after washing and drying the film, but may also be used after its insulation property and chemical resistance is increased by thermal-curing the film, that is, annealing the film at a temperature of 100 ~ 500⁰C for 30 seconds - 180 minutes. Mode for the Invention

[58] [Example 1]

[59] 249.36 g of 3-methacryloxypropylmethoxysilane and 200 g of 2-propanol were put into a three-neck flask provided with a heater and then stirred, and simultaneously, a mixed solution of 2 mL of nitric acid (0.01 mol/L) and 52 mL of pure water was dropped through a funnel provided in the three-neck flask using a filter paper for 30 minutes.

[60] After the temperature of the contents of the three-neck flask became 5O⁰C, the contents was refluxed at room temperature for 12 hours while being heated, so as to obtain a first oligomer solution.

[61] The obtained first oligomer solution was diluted with tetrahydrofuran, and then the weight average molecular weight of the diluted first oligomer solution was measured by a gel permeation chromatography apparatus provided with a refractive index detector using tetrahydrofuran as a carrier. As a result, the measured weight average molecular weight thereof was about 12000.

[62] 100 parts by weight of this first oligomer solution was diluted with 50 parts by weight of propyleneglycol monomethyl ether acetate, and then 1 wt% of 4,4-bis(diethylamino)-benzophenone as a photoinitiator and 1 wt% of a monomer or trimethylpropane triacrylate as a second oligomer were added to the diluted first oligomer solution, so as to obtain a composition.

[63] The composition was applied onto borosilicate glass at a rotation speed of 1000 rpm to form a transparent thin film having a thickness of about 600 nm.

[64] The thin film was pre-baked on a hot plate at 6O⁰C for 3 minutes, and was then irradiated with ultraviolet rays of g, h and i-rays. Immediately, the irradiated thin film was developed by 2.38 wt% of tetramethylammonium hydroxide for 1 minute to obtain a transparent negative pattern.

[65] Thereafter, the obtained negative pattern was post-baked by an electric heater at

22O⁰C for 15 minutes to obtain a final thin film pattern.

[66] The thickness of the thin film was measured using an ellipsometer, and the visible light transmission thereof was measured using an ultraviolet visible spectrophotometer.

[67] The breakdown voltage and leak current of the thin film was measured using a mercury probe and a CV or IV meter after separately providing a substrate obtained by sputtering ITO and then entirely exposing and developing the substrate under the condition that a resolution of 3 μm can be acquired.

[68] The heat resistance of the thin film was determined by abnormality in appearance, such as cloudiness, yellowing or the like, or by whether or not film thickness is decreased after a pattern formed on a glass substrate is heated under a nitrogen atmosphere.

[69]

[70] [Example 2]

[71] The synthesis, film formation, exposure and development were performed in the same manner as Example 1, except that 3-methacryloxypropylethoxysilane as a tri- functional silane monomer was replaced by 3-acryloxypropyltriethoxysilane, and that 4,4-bis(diethylamino)-benzophenone as a photoinitiator was replaced by phosphineox- idephenylbis (2,4,6-trimethylbenzoyl).

[72]

[73] [Example 3]

[74] The synthesis, film formation, exposure and development were performed in the same manner as Example 1, except that 124.68 g of 3-methacryloxypropylmethoxysilane, which is 1/2 of

3-methacryloxypropylmethoxysilane as a trifunctional silane monomer, was mixed with 99.15 g of phenyltrimethoxyl silane, and that trimethylolpropane triacrylate as a monomer or a second oligomer was replaced by bisphenol-A-ethoxylated acrylate.

[75]

[76] [Example 4]

[77] The synthesis, film formation, exposure and development were performed in the same manner as Example 1, except that 124.68 g of 3-methacryloxypropylmethoxysilane, which is 1/2 of

3-methacryloxypropylmethoxysilane as a trifunctional silane monomer, was mixed with 104.17 g of tetraethoxyl silane, that the reflux time was reduced to 2 hours because the hydrolysis of tetraethoxysilane was rapid, and that 4,4-bis (diethylamino)-benzophenone as a photoinitiator was replaced by (s)-2-benzyl-2- (dimethylamino)- 1 - 1 - (4-morpholinophenyl)butane- 1 -one.

[78]

[79] [Comparative Example 1]

[80] A composition was prepared using the same raw material and process as in Example

4, except that the reflux time was 12 hours. In this case, the weight average molecular weight of the composition was 20.000. The composition was applied and dried to form a thin film, and the thin film was entirely cracked, with the result that the thin film could not be exposed and the characteristics of the thin film could not be measured.

[81]

[82] [Comparative Example 2]

[83] The synthesis, film formation, exposure and development were performed in the same manner as Example 1, except that trimethylolpropane triacrylate as a monomer or a second oligomer was not added. As a result, perfect pattern could not be acquired by ultraviolet energy of 100 mJ/cm2 or lower. [84] The results of Examples 1 to 4 and Comparative Examples 1 and 2 are given in Table

1 below. [85] [86] Table 1

[Table 1] [Table ]

[87] MAcP-TMOS: methacryloxypropyl tetramethoxy silane

[88] AcP-TMOS: acryloxypropyl trimethoxy silane

[89] PhTMOS: phenyl trimethoxy silane [90] TEOS: tetraethoxy silane

[91] TPO: phosphineoxidephenylbis(2,4,6-trimethylbenzoyl)

[92] EMK: 4,4-bis(dimethylamino)-benzophenone

[93] IC369: (S)-2-benzyl-2-(dimethylamino)-l-l-(4-morpholinophenyl)butane-l-one

[94] TMPTA: trimethylolpropane triacrylate

[95] BPAEODA: bisphenol-A-ethoxylated diacrylate

[96]

[97] As described above, it can be seen that, when the molecular weight of a silane monomer is more than 10000, the solubility of the composition to a solvent remarkably decreases, and a thin film formed using the composition is cracked, so this silane monomer is not suitable to the present invention. Therefore, it can be found that it is very important to control the final molecular weight of a polymer obtained by polymerizing the silane monomers.

[98] Further, it can be found that trimethylolpropane triacrylate as a monomer or a second oligomer was added to the compositions of the Examples, but was not added to the compositions of Comparative Examples, so that the compositions of Comparative Examples hardly had sensitivity to ultraviolet rays having an energy of 100 mJ/cm² or lower, with the result that it was impossible to pattern the thin films formed using the compositions of Comparative Examples.

[99] Furthermore, it can be found that the hardness of the thin films formed using the compositions including a monomer or a second oligomer of the Examples was more improved.

Claims

[1] A composition for patterning a thermostable transparent insulator thin film, comprising: a first oligomer having a weight average molecular weight of 500 to 10,000, the first oligomer being obtained by hydrolyzing and polymerizing silane represented by the Formula R-CH₂CH₂CH₂Si(OR')₃ (R is a monovalent substituent having at least one ethenyl group, and R' is a monovalent substituent of four carbon atoms or less); a photoinitiator generating a free radical using the irradiation of ultraviolet rays having a wavelength of 365 nm or more; and at least one of a monomer and a second oligomer having two or more unsaturated bonds in one molecule thereof. [2] The composition according to claim 1, wherein the R further has a methacryloxy group. [3] The composition according to claim 1, wherein the at least one of the monomer and the second oligomer is at least one selected from among vinyl ether, acrylate, and vinyl acrylate. [4] A method of patterning a thermostable transparent thin film, comprising the steps of: hydrolyzing and polymerizing silane using an organic solvent to obtain a first oligomer having a weight average molecular weight of 500 to 10,000; adding a photoinitiator to the first oligomer in a weight ratio of 1:0.01 ~ 1:20; adding a monomer or a second oligomer having two or more unsaturated bonds in one molecule thereof to obtain a composition; applying the composition onto a substrate and then drying the applied composition to form a film; irradiating the film with ultraviolet rays having a wavelength of 365 nm to expose the film; and dissolving an unexposed portion of the exposed film using a weak aqueous alkali solution or an organic solvent.