KR100679328B1 - Positive Resist Composition For Forming Organic Insulator of High Aperture LCD - Google Patents

Abstract

The present invention relates to a positive resist composition for forming an organic insulating film of a high-aperture liquid crystal display device containing a binder resin, a photosensitive agent, and a solvent, and a resin represented by the following general formula (1) is used as the binder resin. According to the present invention, the positive resist composition including the binder resin represented by the general formula (1) exhibits a low dielectric constant when forming an organic insulating film of a high opening liquid crystal display device, as well as adhesion to metals and inorganic materials, UV transmittance, residual film rate, and pattern. Formability, chemical resistance, etc. are favorable.

<Formula 1>

Organic insulating film, positive resist composition, binder resin, high opening ratio, liquid crystal display device

Description

Positive Resist Composition For Forming Organic Insulator of High Aperture LCD

1 is a plan view showing a unit cell of a typical TFT having a high opening ratio,

FIG. 2 is a cross-sectional view taken along the line II-II 'of FIG. 1.

The present invention relates to a positive resist composition for forming an organic insulating film of a high-permeability liquid crystal display device, and more particularly, exhibits a low dielectric constant when forming an organic insulating film of a high-opening liquid crystal display device, as well as adhesion to metals and inorganic materials, UV transmittance, The present invention relates to an amphoteric resist composition having excellent physical properties such as residual film ratio, pattern formation property, and chemical resistance.

Generally, liquid crystal displays (hereinafter referred to as LCDs) are used in display devices such as televisions and graphic displays. In particular, an active matrix LCD having a switching element such as a thin film transistor (TFT) for each pixel has a high-speed response characteristic and can be applied to many pixels, which is comparable to a cathode ray tube (CRT). It is greatly contributing to the realization of high quality, large sized, and colorized display screens.

In order to obtain a high quality display screen on the LCD, improvement of the aperture ratio is a priority. Here, the aperture ratio refers to the actual light transmission ratio with respect to the area of the pixel electrode.

In the TFT-LCD, while the demand for its size and high resolution is increasing while the rate of increasing efficiency of the battery does not follow, a method of improving the transmittance of liquid crystals has been developed. As a method of improving the transmittance of a liquid crystal, there are a method of greatly improving the aperture ratio of a liquid crystal panel, a method of improving the transmittance of a polarizing plate, and a method of improving the transmittance of a color filter. Among these methods, a method of improving the aperture ratio of a liquid crystal panel includes arranging ITO pixels having a structure in which an indium tin oxide (ITO) electrode made of a transparent metal called a pixel electrode is arranged on a TFT over the entire pixel region, and the pixels are arranged. Techniques for increasing the area of a pixel electrode have been used. With this technology, the aperture ratio of conventional TFT-LCDs can be improved from 50-60% to about 80-85%.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings to assist in understanding the high-aperture TFT LCD. 1 is a plan view showing a unit cell of a conventional TFT LCD having a high opening ratio. Referring to FIG. 1, the gate lines 2 are disposed in the lateral direction, and the storage electrode lines 4 are disposed in parallel to the positions spaced apart from each other at predetermined intervals. The data line 8 is disposed to vertically pass through the gate line 2 and the storage electrode line 4.

The semiconductor layer 6 is formed in a pattern form on the gate line 2 adjacent to the data line 8, and the drain electrode 9a and the data line 8 drawn out from the data line 8 are formed. ), The source electrodes 9b formed together at the time of formation are arranged on the semiconductor layer 6 so as to overlap each other with a predetermined portion.

On the other hand, a pixel electrode 12 made of ITO is disposed in the pixel region partitioned by the gate line 2 and the data line 8, and at this time, the pixel electrode 12 is in contact with the source electrode 9b, Further, it is disposed over the entire pixel region so as to overlap a part of the data line 8 and the gate line 2.

FIG. 2 is a cross-sectional view taken along the line II-II 'of FIG. 1. As illustrated, the storage electrode 4a is formed on the lower substrate 20 at a position spaced apart from the gate electrode 2a by a predetermined distance, and the gate insulating film 5 is formed on the upper front surface of the lower substrate 20. Is formed. The semiconductor layer 6 is formed on the gate insulating film 5 in the form of a pattern through a known process, and the drain electrode 9a and the source electrode formed together at the time of forming the data line 8 on the semiconductor layer 6. 9b are formed spaced apart from each other.

In addition, an organic insulating film 10 having a low dielectric constant is coated on the upper surface of the lower substrate 20 on which the above-described structure is formed, and the organic insulating film 10 is provided with a contact hole (not shown) for exposing a source electrode. The pixel electrode 12 is formed on the organic insulating layer 10 to be in contact with the source electrode 9b through a contact hole in a portion corresponding to the pixel region and to overlap with a portion of the gate electrode 2a and the data line 8. . Here, the organic insulating film 10 functions to insulate the pixel electrode 12 from the data line 8 and to planarize the lower layer.

In order to form the organic insulating film of FIG. 1, it is common to use a positive resist composition in which a binder resin and a photosensitive agent are added to a solvent. However, when forming an organic insulating film using a positive resist composition containing a conventional binder resin, not only does not exhibit a sufficient low dielectric constant, but also has poor adhesion with metal and a low residual film rate after development, resulting in poor pattern flatness.

Accordingly, the technical problem to be achieved by the present invention is to provide a positive resist composition having good adhesion to the metal, UV transmittance, residual film ratio, flatness and pattern stability, as well as low dielectric constant when forming an organic insulating film of a high-permeability liquid crystal display device. have.

In order to achieve the above technical problem, the present invention relates to a positive resist composition for forming an organic insulating film of a high-aperture liquid crystal display device comprising a binder resin, a photosensitive agent, and a solvent, wherein a resin represented by the following general formula (1) is used as the binder resin: It provides a resist composition.

<Formula 1>

In Formula 1, Z ¹ is independently a linear alkyl group or alkenyl group having 1 to 24 carbon atoms, cyclic alkyl group or alkenyl group, aromatic hydrocarbon (for example, benzene group and phenyl ethyl group), glycidyl group , A (meth) acryl group, a (meth) acrylated alkyl group, an amine group, or a carboxy group, n is an integer of 1-40.

In the positive resist composition for forming an organic insulating film of the high aperture liquid crystal display device of the present invention, as the binder resin, a resin represented by the following general formula (2) can be further added in addition to the binder resin represented by the general formula (1).

<Formula 2>

In Formula 2, a, b, c, d, and e are 0 ≦ a <1, 0 ≦ b <1, 0 ≦ c <1, 0 <d <1, 0 as mole ratios of the monomers. <e <1, where 0 <a + b <1, a + b + c + d + e = 1, and X is independently of each other a hydrogen atom or an alkyl group having 1 to 5 carbon atoms (methyl group, ethyl group, n-propyl group) , Isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, etc.), Y ¹ and Y ² are each independently an alkyl group having 1 to 12 carbon atoms, Cyclic alkyl group, hydroxy alkyl group, benzene group, phenylethyl group, amine, amide, carbamate or alkyl group including urea, Y ³ is aromatic hydrocarbon (phenyl group, naphthyl group, etc.), Z is carbon number It is an alkyl group, cyclic alkyl group, or aromatic hydrocarbon (benzene group, phenylethyl group etc.) which are 1-24, l, m, and n are the integers of 1-12, respectively, and k is an integer of 0-6.

The positive resist composition for forming an organic insulating film of the high aperture liquid crystal display device of the present invention may further include a silicon-based compound including an epoxy group or an amine group.

EMBODIMENT OF THE INVENTION Hereinafter, the positive resist composition for organic insulating film formation of the high aperture liquid crystal display element of this invention is demonstrated in detail.

As described above, it is common to use a positive resist composition in which a binder resin and a photosensitive agent are added to a solvent for forming an organic insulating film (see Korean Patent Publication No. 10-2004-32468). The present inventors use the resin represented by the general formula (1) as the binder resin used in the positive resist composition, and not only exhibit low dielectric constant when forming an organic insulating film, but also adhesion to metal, UV transmittance, residual film ratio, flatness and pattern stability. Good positive resist compositions have been developed.

Resin of the general formula (1) is a resin formed by the condensation reaction of a silicon compound, and when used as a binder resin in the positive resist composition can form a low dielectric constant organic insulating film, it is possible to achieve a thin film of the organic insulating film. This improves process yield and reduces manufacturing costs. The resin of the general formula (1) preferably has an average molecular weight of 500 to 20,000 and a dispersion degree of 1 to 5.0, and more preferably an average molecular weight of 1,000 to 10,000 and a dispersion degree of 1.1 to 2.5.

On the other hand, in the positive resist composition for forming an organic insulating film of the high-opening-rate liquid crystal display device of the present invention, in addition to the binder resin represented by the general formula (1) as the binder resin, the above-mentioned general formula (2) which is a copolymer of a monomer containing a carboxylic acid and a monomer having a double bond It is preferable to further add a resin represented by, for example, the resin of Formula 1 and the resin of Formula 2 may be contained in a weight ratio of 0.1: 99.9 to 99.9: 0.1. If the pattern is formed after coating with the positive resist composition containing the resin of the general formula (1) and the resin of the general formula (2) as the binder resin, there is an advantage such that there is no defect such as residue after development and the planarization rate is further excellent. In particular, Y ¹ and Y ² of the general formula 2 are each independently an alkyl group having 1 to 12 carbon atoms, a cyclic alkyl group, a hydroxy alkyl group, a benzene group, a phenylethyl group, etc. It can be controlled and help improve adhesion. In addition, unlike conventional binder resins made of acrylic copolymer resins containing an aromatic group, Y ³ can not only increase the residual film ratio by including a bulky substituted group structure, but also increase the glass transition temperature, thereby increasing heat resistance and resistance to heat. It improves chemistry and transparency. On the other hand, the curability and residual film ratio of the positive resist is improved by the acrylate containing carbamate. In addition, since a carboxylic acid in the form of a chain including a carboxylic ester is present in the main chain, the degree of curing is increased and developability is improved.

The average molecular weight of the resin of Formula 2 is 2,000 to 50,000, the dispersity is 1.0 to 5.0 and the acidity is preferably used is 30 to 400 KOHmg / g, the average molecular weight is 5,000 to 40,000 and the dispersity is 1.6 to 3.0 Most preferably, the acidity is 50 to 150 KOHmg / g.

In the positive resist composition for forming an organic insulating film of the high aperture liquid crystal display device of the present invention, the preferred amount of binder resin is 10 to 40% by weight based on the total weight of the composition.

 The silicon-based compound containing an epoxy group or an amine group can be further added to the positive resist composition for forming an organic insulating film of the high aperture liquid crystal display device of the present invention. When the silicone-based additive having an epoxy group or an amine group is added, the adhesion between the ITO electrode and the positive resist composition is further improved, and the heat resistance property after curing is also improved. Such silicone compounds include (3-glycidoxypropyl) trimethoxy (ethoxy) silane (3-glycidoxypropyl) methyldimethoxy (ethoxy) silane, (3-glycidoxypropyl) dimethyldimethyl Oxy (ethoxy) silane, 3,4-epoxybutyltrimethoxy (ethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxy (ethoxy) silane, N- (2 -Aminoethyl) -3-aminopropyldimethoxymethylsilane, (3-aminopropyl) trimethoxysilane, (3-aminopropyl) triethoxysilane, (3-mercaptopropyl) trimethoxysilane Phosphorus, (N, N-diethyl-3-aminopropyl) trimethoxysilane, N-beta (aminoethyl) gamma-aminopropyltrimethoxysilane, and the like, each of which can be used alone or in combination thereof. Can be. The preferred content for the addition of silicone-based additives having epoxy or amine groups is 0.001 to 0.1% by weight, based on the total weight of the composition.

The above-mentioned binder resin forms a positive resist composition by adding a solvent together with a photosensitizer, spin coating the substrate and then forming an organic insulating layer by irradiating ultraviolet rays using a mask and developing with an alkali developer.

As the photosensitive agent contained in the positive resist composition of the present invention, a photosensitive agent that is commonly used may be used, but it is preferable to use the photosensitive agent described in Korean Laid-Open Patent Publication No. 10-2004-32468. The preferred amount of the photosensitizer is 1 to 20% by weight based on the total weight of the composition.

In addition, as the solvent added to the positive resist composition of the present invention, a solvent that is commonly used may also be used. Considering compatibility with binder resins, photosensitizers, and other compounds, diethylene glycol dimethyl ether (DMC), diethylene glycol Methyl ethyl ether (MEC), methyl methoxy propionate, ethyl ethoxy propionate (EEP), ethyl lactate, propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether, propylene glycol propyl ether, methyl cello Solvate, ethyl cellosolve acetate, diethylene glycol methyl acetate, diethylene glycol ethyl acetate, methyl isobutyl ketone, cyclohexanone, dimethyl formamide (DMF), N, N-dimethylacetamide (DMAc), N- Methyl-2-pyrrolidone (NMP), gamma-butyrolactone, diglyme, methyl cellosolve, ethyl cellosolve, diethylene glycol methyl ether, Ethylene glycol ethyl ether, dipropylene glycol methyl ether and the like it is preferred to use them alone or in a mixture of two or more of the. The solvent is preferably added so that the viscosity of the positive resist composition is in the range of 2 to 30 cps, and more preferably, to adjust the viscosity to 10 to 25 cps, there is no pin hole of the thin film after coating and the thickness of the thin film. It is more advantageous to control.

 The positive resist composition for forming an organic insulating film of the high aperture liquid crystal display device according to the present invention has the compatibility of a photosensitizer, a thermal polymerization inhibitor, an antifoaming agent, a leveling agent and the like within the range of not impairing the object of the present invention as necessary. Of course, other known additives can be added.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, embodiments according to the present invention can be modified in many different forms, the scope of the present invention should not be construed as limited to the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

<Preparation of Binder Resin>

Resin of Formula 1

Table 1 shows the resin compounds corresponding to Formula 1 according to the type and content of Z ¹ . The average molecular weight of the resin compounds listed in Table 1 was about 4,000 and the degree of dispersion was about 1.5.

Resin of Formula 2

Table 2 shows the resin compounds corresponding to Formula 2. The average molecular weights of the resin compounds listed in Table 2 were about 20,000 to 21,000, the dispersity was about 2.2 to 2.3, and the acidity was about 105 to 115.

In Table 2, the molar ratio (a: b: c: d: e) of General Formula 2a is 55: 10: 0: 10: 35, and the molar ratio (a: b: c: d: e) of General Formula 2b is 25. : 25: 0: 15: 35, the molar ratio (a: b: c: d: e) of General Formula 2c is 25: 20: 0: 40: 15, and the molar ratio of General Formula 2d (a: b: c: d: e) is 10: 30: 15: 15: 30.

Resin of the general formula 2 was synthesized as follows.

Synthesis of Formula 2a

236.5 g of monomeric benzyl methacrylate, 34.7 g of glycidyl methacrylate, 31.8 g of 2-hydroxyethyl methacrylate, and 73.6 g of methacrylic acid were 14 g of azobisisobutyronitrile (AIBN) and propylene. 610 g of glycol monomethyl acetate was charged into a polymerization tank, and stirred at 80 ° C for 5 hours to obtain a solution of 1000 g of a raw material polymer.

100 g of the solution was added, 3.8 g of 2-methacryloyloxyethyl isocyanate (MOI) and 0.5 g of dibutyl tin dilaurate were added and stirred at room temperature for 3 hours, followed by 0.01 g of hydroxyquinone 10 Stirring again for minutes gave a resin of formula 2a. Obtained resin had an average molecular weight of 20,500, a distribution of 2.2 and an acidity of 110.

Synthesis of Formula 2c

143.9 g of monomeric dicyclopentanyl methacrylate, 69.1 g of glycidyl methacrylate, and 174.02 g of 2-hydroxyethyl methacrylate are 14 g of azobisisobutyronitrile (AIBN) and 610 g of propylene glycol monomethyl acetate. It put in the superposition | polymerization tank which was thrown in, and it stirred at 80 degreeC for 5 hours, and obtained the solution of 1000 g of raw material polymer.

100 g of the solution was added, 15.1 g of 2-methacryloyloxyethyl isocyanate (MOI) and 2 g of dibutyl tin dilaurate were added and stirred at room temperature for 3 hours, followed by 0.01 g of hydroquinone for 10 minutes. Stir again. Subsequently, 7.61 g of trimellitic anhydride was added thereto, 0.06 g of dimethylaminopyridine and 0.03 g of triethylamine were added, followed by stirring at room temperature for 24 hours to obtain a resin of the general formula 2c. The average molecular weight of the obtained resin was 21,000, the degree of distribution was 2.3, and the acidity was 109.5.

Since the resin synthesis method of another general formula 2 can be easily derived from the above-mentioned synthesis method, description is abbreviate | omitted.

<Examples 1 to 16>

A positive resist composition was prepared according to the composition and content shown in Table 3 below in a reaction mixing tank equipped with an ultraviolet ray blocking film and a stirrer, and stirred at room temperature, and a solvent was added to the composition to obtain a high-aperture liquid crystal display device having a viscosity of about 15 cps. A positive resist composition for forming an organic insulating film was prepared.

In Table 3, 2,3,4,4'-tetrahydroxybenzophenone naphthoguinon-1,2-diazito-5-sulfonic acid ester was used as the photosensitizer, and the silane epoxy compound (3- Glycidoxypropyl) trimethoxysilane was used, and the leveling agent was R-08 from DIC Corporation.

<Comparative Examples 1 to 5>

Examples 1 to 5 (Comparative Example 1-Example 1, Comparative Example 2-Example 2, ...) and except that the binder resin represented by the following formula (3) instead of the binder resin of Example 1 A positive resist composition for forming an organic insulating film of a high aperture liquid crystal display device was prepared using the same components and contents.

<Formula 3>

In Formula 3, o is 0.52, p is 0.3, q is 0.08, r is 0.1, the average molecular weight is 20,000.

In the above Examples and Comparative Examples, the evaluation of the positive resist composition was performed on a substrate such as a silicon wafer or a glass plate, and performance was evaluated according to the following criteria, and the results are shown in Tables 4 and 5 below.

(1) permittivity measurement

A positive resist composition was formed on the substrate on which the aluminum electrode was formed using a spin coater to form a resist film, and a dielectric constant measuring cell was fabricated. The dielectric constant was measured using an impedance analyzer.

(2) Adhesion with metals and inorganics

The resist composition was applied to the substrate using a spin coater at a speed of 650 rpm for 20 seconds, then prebaked at 90 ° C. for 2 minutes, exposed at 365 nm for 15 seconds, and then post-baked at 220 ° C. for 60 minutes. To form a resist film, which was placed in an autoclave and aged at 100 ° C for 1 hour. The specimens aged in the autoclave are scratched to expose the substrate with a cross hatch cutter, and then attached with an adhesive tape and then detached. If more than 80 cells out of 100 cells are not detached from the substrate, it is determined as 'good' or 'bad'.

(3) UV transmittance

The resist composition was applied to the substrate using a spin coater at a rate of 650 rpm for 20 seconds, then prebaked at 90 ° C. for 2 minutes, soaked in TMAH 2.38% solution for 50 seconds, and then rinsed with DI water for 60 seconds. Thereafter, the resultant was blown with compressed air, exposed to light for 40 seconds (bleaching), and then subjected to postbake at 220 ° C. for 60 minutes to form a resist film having a thickness of about 3.0 to 3.5 micrometers (um). The transmittance of the 400 nm region was measured by transmission.

(4) residual rate

The resist composition was spin-coated on a substrate, the thickness after pre-baking and the thickness ratio (%) of the formed film were measured after removing the solvent by post-baking.

(5) pattern formation

The silicon wafer in which the resist pattern was formed was cut from the vertical direction of the hole pattern, and the result of observing with the electron microscope in the cross-sectional direction of the pattern was shown. The pattern side wall was erected at an angle of 80 degrees or more with respect to the substrate, the film was not reduced, and it was determined as 'good', and the reduction of the film was judged as 'film'.

(6) chemical resistance

After applying the resist composition on the substrate using a spin coater, the resist film formed through a process such as prebake and postbake is applied to a stripper and etchant solution at 40 ° C. for 10 minutes. After soaking, the transmittance and thickness of the resist film were examined. When there was no change in transmittance and thickness, it was set as 'good', and when there was a change in transmittance and thickness, it was determined as 'poor'.

As described above, the positive resist composition including the binder resin according to the present invention not only exhibits low dielectric constant, but also has good adhesion to metals and inorganic materials, UV transmittance, residual film rate, pattern formation property, chemical resistance, and the like. It can be usefully used for forming the organic insulating film of the aperture ratio liquid crystal display device.

Claims (9)

In the positive resist composition for forming an organic insulating film of a high aperture liquid crystal display device comprising a binder resin, a photosensitive agent and a solvent, A positive resist composition for forming an organic insulating film of a high-aperture liquid crystal display device, characterized in that the binder resin comprises a resin represented by the following general formula (1) and a resin represented by the following general formula (2); <Formula 1>

In Formula 1, Z ¹ is independently a linear alkyl group or alkenyl group having 1 to 24 carbon atoms, cyclic alkyl group or alkenyl group, aromatic hydrocarbon, glycidyl group, (meth) acryl group, (meth) acryl Any one selected from the group consisting of a linked alkyl group, an amine group and a carboxyl group, and n is an integer of 1 to 40. <Formula 2>

In Formula 2, a, b, c, d, and e are 0 ≦ a <1, 0 ≦ b <1, 0 ≦ c <1, 0 <d <1, 0 as mole ratios of the monomers. <e <1, where 0 <a + b <1, a + b + c + d + e = 1, X is independently of each other a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and Y ¹ and Y ² are each Independently selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cyclic alkyl group, a hydroxy alkyl group, a benzene group, a phenylethyl group, an amine, an amide, a carbamate or an urea, or an alkenyl group; ³ is an aromatic hydrocarbon, Z is any one selected from the group consisting of an alkyl group having 1 to 24 carbon atoms, a cyclic alkyl group and an aromatic hydrocarbon, l, m and n are each an integer of 1 to 12, k is 0 to 6 Integer of. The positive resist composition for forming an organic insulating film of a high-aperture liquid crystal display device according to claim 1, wherein the average molecular weight of the resin represented by the general formula (1) is 500 to 20,000 and dispersion degree is 1 to 5.0. delete According to claim 1, wherein the average molecular weight of the resin represented by the general formula (2) is 2,000 to 50,000, the dispersion degree is 1.0 to 5.0, the acidity is 30 to 400 KOHmg / g of the high-aperture rate liquid crystal display device A positive resist composition for forming an organic insulating film. The organic insulating film of claim 1, wherein the content ratio (wt%) of the resin represented by Formula 1 and the resin represented by Formula 2 is 0.1: 99.9 to 99.9: 0.1. Positive resist composition for formation. The positive resist composition of claim 1, further comprising a silicon compound containing an epoxy group or an amine group. The method of claim 1, wherein the binder resin is contained in an amount of 10 to 40% by weight based on the total weight of the composition, and the content of the photosensitizer is 1 to 20% by weight. Positive resist composition. 8. The positive resist composition for forming an organic insulating film of the high-opening liquid crystal display device according to claim 7, further comprising 0.001 to 0.1% by weight of a silicon compound containing an epoxy group or an amine group. 8. The positive resist composition for forming an organic insulating film of the high aperture liquid crystal display device according to claim 7, wherein the solvent is added so that the viscosity of the composition is 2 to 30 cps.

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