KR20030023388A - Covering compound for gate insulation film of tft-lcd and method for preparing thereof - Google Patents

Abstract

PURPOSE: A gate insulating layer coating composition for a TFT-LCD and its preparation method are provided, to improve a dielectric constant, the heat resistance, the hardness and the transmittance and to enable a thick gate metal to be smooth easily. CONSTITUTION: The gate insulating layer coating composition comprises 5-40 parts by weight of a matrix polymer comprising a polyphosphazene polymer represented by the formula 1 or a polyphosphazene copolymer represented by the formula 2; 10-50 parts by weight of a metal compound selected from the group consisting of a metal alkoxide, a metal oxide particle, and their sol; and 10-85 parts by weight of a solvent, wherein n is an integer of 10-1,000,000; and R1 and R2 are H or CH3, respectively. Preferably the polyphosphazene polymer is prepared by the method comprising the solid state polymerization of hexachlorocyclotriphosphazene at a temperature of 200-300 deg.C; and the polyphosphazene copolymer is prepared by the method comprises a step of polymerizing the polyphosphazene polymer with a substituted methyl phenol and a catalyst with heating.

Description

TFF-LCC gate insulating film coating composition and its manufacturing method {COVERING COMPOUND FOR GATE INSULATION FILM OF TFT-LCD AND METHOD FOR PREPARING THEREOF}

The present invention relates to a gate insulating film coating composition of a TFT-LCD and a method of manufacturing the same. More particularly, the present invention relates to a coating composition having excellent dielectric constant and usable as a gate insulating film for a thin film transistor of an active matrix liquid crystal display device.

U.S. Patent No. 4,839,402 and U.S. Patent No. 4,789,563 refer to sol-gel formation of silica, titania, and alumina, and to thereby improve adhesion. It describes how to use organic matter.

So far, soluble polyimide materials have been described by Kurosaki et al. (Macromolecules, 1994, 27, 1117) and aliphatic using alicyclic anhydrides as monomers to increase dissolution. There is a paper by Kil-Young Choi et al. Using alicyclic dianhydride and a paper by Qn Jin et al. That produced soluble polyimides using cyclic diamines. However, these materials have weak disadvantages such as electrical properties and adhesion required as the gate insulating film material of the thin film transistor.

In addition, US Pat. No. 5,942,592 and US Pat. No. 5,728473 describe a method for producing a polyimide resin including a siloxane group.

In general, a thin film transistor used as a switching element for driving a pixel electrode of a liquid crystal display device has a gate electrode and a source drain electrode formed between an active layer of amorphous silicon or a polycrystalline silicon semiconductor layer. The double gate electrode and the active layer are formed of a gate insulating film. It is separated and a nitride film is generally used. However, in the case of manufacturing a thin film display device having a large area with high demand and high resolution, RC line delay occurs. As a way to solve this problem, the gate metal resistance is increased by increasing the thickness of the gate metal. There is a reduction. However, in the above method, when the nitride film is used as the gate insulating film, there is a problem in that shortening occurs easily between the gate electrode and the source drain electrode due to the lack of planarization characteristics.

Therefore, it is necessary to study the composite material for the gate insulating film that can be coated and the planarization is easy and the dielectric constant of the electrical characteristics of the insulating film can be adjusted.

In view of the problems of the prior art, the present invention can be coated to planarize a thick gate metal, and can be easily adjusted as a dielectric constant among electrical characteristics of the insulating film. It is an object to provide a coating composition which can be used.

Another object of the present invention is to provide a method of manufacturing a gate insulating film for a thin film transistor of a liquid crystal display device having a dielectric constant corresponding to a conventional silicon nitride film.

1 and 2 are enlarged photographs 30,000 times of an insulating film composition prepared from the polyphosphazene polymer of Example 8 with an electron microscope.

3 is a graph showing the dielectric constant and refractive index of the gate insulating film of Example 12;

In order to achieve the above object, the present invention provides a gate insulating film coating composition for a thin film transistor of a liquid crystal display device.

a) iii) a polyphosphazene polymer represented by Formula 1 below; or

Ii) a polymer which is a polyphosphazene copolymer represented by the following formula (2)

Matrix polymer comprising a;

b) selected from the group consisting of metal alkoxides, metal oxide particles, and sol thereof

Metal compound taken

c) solvent

It provides a gate insulating film coating composition comprising:

[Formula 1]

In the formula of Formula 1,

n is an integer from 10 to 1,000,000.

[Formula 2]

In the formula (2),

R ₁ and R ₂ are each H or CH ₃ ,

n is an integer from 10 to 1,000,000.

In addition, the present invention is a method of manufacturing a gate insulating film for a thin film transistor of a liquid crystal display device

a) iii) a polyphosphazene polymer represented by Formula 1 below; or

To include a polymer which is a polyphosphazene copolymer represented by the formula (2)

Is a matrix polymer;

Ii) from the group consisting of metal alkoxides, metal oxide particles, and sols thereof

Metal compound chosen

Iii) solvent

Blending and preparing a mixed coating solution;

b) coating the mixed coating solution on a substrate to form a coating film; And

c) heating and curing the coating film

It provides a method of manufacturing a gate insulating film comprising a.

Hereinafter, the present invention will be described in detail.

The present invention is excellent in heat resistance, solubility, and adhesion, polyphosphazene polymer represented by the formula (1), or polyphosphazene copolymer represented by the formula (2) capable of spin coating capable of sufficiently planarizing a thick gate metal It is to provide a gate insulating film coating composition comprising a polymer and a method for producing a gate insulating film.

Such a polymer is suitable as a matrix in the gate insulating film for a thin film transistor of a liquid crystal display device.

To this end, hexachlorocyclotriphosphazene is subjected to solid phase polymerization at a high temperature of 200 to 300 ° C. to prepare a polyphosphazene polymer represented by Chemical Formula 1, which is dissolved in a solvent and added with a substituted methyl phenol and a catalyst. To prepare a polyphosphazene copolymer polymer represented by the formula (2) by heating and polymerization.

The solvent is methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, dimethyl ether, prehylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol ethyl methyl acetate And at least one member selected from the group consisting of chloroform, methyl ether acetate, ethyl-3-ethoxypropionate, ethyl cellosolve acetate, and butyl acetate.

The substituted methyl phenol is added in the same molar ratio as polyphosphazene.

In addition, the polymerization is preferably carried out for 24 to 48 hours at a temperature of 200 to 300 ℃.

The present invention provides an organic-inorganic composite material comprising a polyphosphazene polymer represented by Chemical Formula 1 or a polyphosphazene copolymer polymer represented by Chemical Formula 2 as a matrix. The organic-inorganic composite material includes metal compounds of metal alkoxides, metal oxide particles, or sol thereof in addition to the matrix polymer, and the metal compounds are evenly dispersed in a matrix polymer, and the metal compound is in the form of a sol in the matrix polymer. When mixed with, it forms a sol-gel composite.

To this end, the mixed weight ratio of the polymer and the metal compound is preferably 10 to 90:90 to 10. At this time, if the mixing weight ratio is less than the above range, there is a problem that the organic-inorganic composite material is soft, and if it exceeds the above range, there is a problem that there is no elasticity and it is easily broken.

The metal alkoxide is preferably selected from the group consisting of silicon alkoxide, titanium alkoxide, zirconium alkoxide, barium alkoxide and aluminum alkoxide, and the metal oxide particles are selected from the group consisting of silica, titania, zirconia, and alumina. It is preferable.

In addition, the sol compound prepared from the metal alkoxide or metal oxide particles is hydrolyzed and condensation reaction by adding tertiary distilled water to each metal alkoxide or metal oxide, and adding the ratio or equivalent ratio of each metal alkoxide or metal oxide. It is prepared through, the content of the metal alkoxide and metal oxide is preferably 20 to 80% by weight. At this time, the acid catalyst to the reaction further comprises 0.01 to 0.5% by weight based on the third distilled water. The acid catalyst is preferably selected from the group consisting of hydrochloric acid, nitric acid, acetic acid, and itaconic acid. In addition, 5 to 15% by weight of ethanol, or 0.5 to 1.5 equivalents of acetyl acetonate, may be added to the water added for controlling the reactivity.

Therefore, such an organic-inorganic composite material is preferred as a gate insulating film for thin film transistors of the liquid crystal display device because of excellent insulation, coating properties, heat resistance, hardness, and transmittance, and easy to control the dielectric constant.

In addition, the present invention provides a gate insulating film coating composition capable of spin coating capable of sufficiently flattening a thick gate metal with excellent heat resistance, permeability, adhesion, and insulation. In other words, the polymer and metal alkoxide, metal oxide particles or sol compounds thereof are provided through the sol-gel reaction or mixed to provide a gate insulating film coating composition of the thin film transistor. This method can be used in the production of large-scale advanced TFT-LCDs by manufacturing a gate insulating film of a thin film transistor having excellent coating property, adhesion, heat resistance, and chemical resistance.

To this end, the coating composition is easy to prepare an insulating film by dispersing and dissolving the polymer and the metal compound in a solvent.

The solvent dissolves the polymer component and facilitates dispersion of the sol-gel solution. At this time, it is preferable to disperse | distribute and dissolve 5-20 weight part of coating composition polymers and 10-35 weight part of metal compounds to 45-85 weight part of solvents.

The solvent may be used as the solvent used in the preparation of the polymer, gamma butyrolactone, dimethylacetamide, N-methylpyrrolidone, methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone, methyl cellosolve, Ethyl cellosolve, tetrahydrofuran, dimethyl ether, prepropylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol ethyl methyl acetate, chloroform, methyl ether acetate, ethyl-3-ethoxypropionate, ethyl cellosolve It is preferable to select at least one from the group consisting of acetate, and butyl acetate.

Such a gate insulating film coating composition may be prepared by the following two methods.

One may use a hybrid method of mixing various metal alkoxides or metal oxide particles with a solvent in the polyphosphazene polymer represented by Chemical Formula 1 or the polyphosphazene copolymer polymer matrix represented by Chemical Formula 2 as it is.

The other is to form a sol-gel composite material by forming a sol from metal alkoxide or metal oxide particles, obtaining a reaction product, mixing with a solvent, and then uniformly dispersing the matrix polymer.

In addition to the basic components, the coating composition may be used by adding a small amount of a defoaming agent, a surfactant, and the like in order to improve the film forming performance as necessary.

The present invention provides a method of manufacturing a gate insulating film for a thin film transistor of a liquid crystal display device corresponding to the dielectric properties of a conventional nitride film. That is, a gate insulating film is manufactured using the coating composition.

First, uniformly disperse and mix the polymer, the metal compound, and the solvent component. At this time, the weight of the polymer, the metal compound, and the solvent is as described above. In addition, the solvent may further impart reactivity to aminopropylsiloxane to prevent phase separation between phases.

Next, the coating liquid obtained above is performed on a substrate (substrate). That is, the finally obtained sol-gel composition solution is obtained transparently, and adjusted to a solid content of 5 to 30% by weight, and filtered using a membrane filter of 0.1 to 5 탆. This filtered resin composition is formed into a film at 1000 rpm for 15 to 30 second using well-known methods, such as a spin coating method, a roll coating method, and a spray coating method. A glass plate or a silicon wafer can be used as a film forming substrate. At this time, the thickness of the film surface is determined by the film forming conditions such as the viscosity of the composition, the concentration of the solid content, the film forming speed and the like, preferably a thin film of 0.1 to 10 ㎛ thickness can be obtained.

Next, the step of heat-treating the thin film under a constant condition to produce a gate insulating film. The present invention is pre-treated while maintaining the obtained thin film for 100 seconds to 500 seconds using a heating plate or oven at a temperature of 50 to 150 ℃, and then subjected to a post-heat treatment at a temperature of 200 to 300 ℃ to obtain a gate insulating film having excellent physical properties You can get it.

The present invention can manufacture a large sized advanced TFT-LCD by a conventional method including the gate insulating film.

As described above, according to the present invention, a polyphosphazene polymer having excellent heat resistance and adhesiveness is provided, and a metal alkoxide, a metal oxide particle, or a sol compound thereof is used as a sol material having excellent insulation properties. By using the gel reaction uniformly mixed to improve the physical properties such as coating properties, adhesion and heat resistance can provide a composite material excellent in transparency, insulation properties and the like. Accordingly, the present invention can provide a gate insulating film having excellent physical properties using the composite material and a TFT-LCD including the same.

The dielectric constant of the insulating film composition including the polyimide copolymer prepared in the present invention is preferably? '= 7.

The present invention will be described in more detail with reference to the following examples and comparative examples. However, an Example is for illustrating this invention and is not limited only to these.

EXAMPLE

Example 1

(Polyphosphazene polymer production)

Hexachlorocyclotriphosphazene was purified by vacuum sublimation apparatus and recrystallized with hexane, and then 6.13 g (0.053 mol) of polydichlorophosphazene was placed in a vacuum-sealed test tube and subjected to solid phase polymerization at 250 ° C. The substituted methyl phenol was purified by vacuum sublimation and then dried in a dryer. Sodium hydride (NaH) was purified with hexanes. The polymerized polyphosphazene is dissolved in tetrahydrofuran (THF). 6.5 g (0.055 mol) of substituted methyl phenol and 1.2 g (0.055 mol) of sodium were slowly added dropwise to a mixture of tetrahydrofuran and tetra-n-butylammonium bromide.

In a 3 L vessel, 12.05 g (0.524 mol) of sodium metal was dissolved in a solution of Tetrahydrofuran (THF). Substituted methyl phenol was dissolved in Tetrahydrofuran solution, and then slowly added dropwise to sodium solution. It was stirred at room temperature for 12 hours and reacted at 60 ° C for 12 hours. Hexachlorocyclotriphosphazene was dissolved in Tetrahydrofuran solution, added dropwise to sodium solution, and then reacted for 48 hours. The mixture was cooled, filtered through silica gel, dissolved in diethyl ether, and then 0.05 M sodium hydroxide solution. Extracted with and recrystallized with hexane.

Example 2

(Polyphosphazene polymer production)

Hexachlorocyclotriphosphazene was purified by vacuum sublimation apparatus and recrystallized with hexane, and then 6.13 g (0.053 mol) of polydichlorophosphazene was placed in a vacuum-sealed test tube and subjected to solid phase polymerization at 250 ° C. The substituted methyl phenol was purified by vacuum sublimation and then dried in a dryer. Sodium hydride (NaH) was purified with hexanes. The polymerized polyphosphazene is dissolved in tetrahydrofuran (THF). 6.5 g (0.055 mol) of substituted methyl phenol and 1.2 g (0.055 mol) of sodium were slowly added dropwise to a solution of tetrahydrofuran and tetra-n-butylammonium bromide. The polyphosphazene thus obtained was dissolved in a dimethylacetamide (DMAc) solvent and the viscosity was measured at 25 ° C., and the result was 0.3 to 0.5 dL / g.

(Manufacture of insulating film composition)

6 wt% of the polyphosphazene prepared above was dissolved in dimethylacetamide (DMAc), and a fluorinated planarizing agent was added to obtain a solution having a viscosity of 10 to 15 cP. It was spin coated at 1000 rpm for 30 seconds and heat treated at 100 ° C. for 30 minutes and at 190 ° C. for 1 hour to obtain a 0.18 μm thick film. In addition, the film had excellent adhesion on the glass surface, and the pencil hardness was 3 to 4 H, which could be used as a gate insulating film material.

Example 3

Except for adding polyphosphazene in 8% by weight of dimethylacetamide in Example 2 was carried out in the same manner as in Example 2 to obtain a 0.36 ㎛ thick film. Moreover, the pencil hardness of the said film was 3-4H, and it was possible to use it as a gate insulating film material.

Example 4

A 0.5 μm-thick film was obtained by the same method as Example 2, except that polyphosphazene was added to dimethylacetamide in 10 wt% in Example 2. Moreover, the pencil hardness of the said film was 3-4H, and it was possible to use it as a gate insulating film material.

Example 5

A film having a thickness of 0.67 μm was obtained in the same manner as in Example 2, except that polyphosphazene was added to dimethylacetamide in 12 wt% in Example 2. Moreover, the pencil hardness of the said film was 3-4H, and it was possible to use it as a gate insulating film material.

Example 6

Except for adding polyphosphazene 14% by weight to dimethylacetamide in Example 2 it was carried out in the same manner as in Example 2 it could be obtained a film of 1.07 ㎛ thickness. Moreover, the pencil hardness of the said film was 3-4H, and it was possible to use it as a gate insulating film material.

Example 7

The polyphosphazene prepared in Example 1 was made into 5% solution in tetrahydrofuran, and a mixed solution was prepared by adding benzophenone, a photoinitiator (benzophenone / phosphazene = 0.01 to 0.25). The mixed solution was cast on a sodium chloride support plate and then dried in air for 12 hours under light blocking conditions. The 60 μm thick film was dried in a vacuum dryer, and then the sodium chloride support plate was covered thereon and each corner was sealed. After fixing the film in the ultraviolet lamp chamber, argon gas was injected for 20 minutes, and the ultraviolet lamp was injected for 300 minutes to prepare an ultraviolet cured film.

Example 8

To prepare an organic-inorganic composite material for a gate insulating film, 15% by weight of the polyphosphazene prepared in Example 1 was added to a gamma butyrolactone, dimethylacetamide, and N-methylpyrrolidone solvent, followed by In order to prevent phase separation, 0.5-1.5 equivalents of gamma amino propylsiloxane was mixed to prepare a reactive polyphosphazene.

The metal alkoxide was mixed with siloxane alkoxide and tertiary distilled water in an equivalent ratio, followed by spin coating at 1000 rpm for 15 to 30 seconds to obtain a thin film having a thickness of 0.3 to 0.5 µm. After heating for 3 hours at 70 ~ 90 ℃, and condensation reaction by heating for 3 hours under a nitrogen atmosphere of 300 ℃, a gate insulating film was prepared by magnification 30000 times with an electron microscope to see the results of Figures 1, 2 Shown in

As shown in Figures 1 to 2, it can be seen that the size of the dispersed particles of the gate insulating film containing the polyphosphazene polymer of the present invention is reduced.

Example 9

A gate insulating film was prepared in the same manner as in Example 8, except that titanium tetraisopropoxide was used as the metal alkoxide in Example 8 and ethyl sol was used to relax the sol-gel reaction.

Example 10

A gate insulating film was prepared in the same manner as in Example 8 except that zirconium alkoxide was used as the metal alkoxide in Example 8.

Example 11

A gate insulating film was prepared in the same manner as in Example 8 except that aluminum alkoxide was used as the metal alkoxide in Example 8.

Example 12

After preparing the polyphosphazene solution prepared in Example 1 to 5 to 15% by weight, 4 to 20 nm of titania is dispersed uniformly to 0, 27.3, 42.9, 52.9, and 60% by weight of metal oxide particles, respectively. The composite stock solution was prepared and spin coated at 1000 rpm for 30 seconds to obtain a gate insulating film having a thickness of 0.3 to 0.5 µm, heated at 70 to 90 ° C. for 30 minutes, and heated at 150 to 200 ° C. for 1 hour. The transmittance, refractive index, and dielectric constant were measured by heating, and the results are shown in Table 1 and FIG. 3.

division Titania0 wt% Titania 27.3 wt% Titania42.9 wt% Titania 52.9 wt% Titania60 wt% Transmittance (400 nm, 0.35 μm thick) 97 96 96 96 95 Refractive index 1.554 1.701 1.755 1.862 1.924

Example 13

A gate insulating film having a transmittance of 95% or more and a surface hardness of 3 to 4 H at 400 nm was obtained in the same manner as in Example 13, except that alumina was used as the metal oxide particle in Example 12.

Example 14

Except for using zirconia as a metal oxide particle in Example 12, a gate insulating film having a transmittance of 95% or more at 400 nm and a surface hardness of 3 to 4 H was obtained in the same manner as in Example 13.

According to the present invention, there is provided a polyphosphazene polymer having excellent solubility, heat resistance, and adhesiveness, and further comprising coating property using metal alkoxide, metal oxide particles, or sol compounds thereof as a sol material having excellent insulation properties. An organic-inorganic composite material for a gate insulating film exhibiting excellent physical properties in hardness and transmittance can be provided. In another aspect, the present invention can provide a gate insulating film having excellent physical properties and a TFT-LCD comprising the same using the composite material.

Claims (10)

A gate insulating film coating composition for a thin film transistor of a liquid crystal display device, a) iii) a polyphosphazene polymer represented by Formula 1 below; or Ii) a polymer which is a polyphosphazene copolymer represented by the following formula (2) Matrix polymer comprising a; b) selected from the group consisting of metal alkoxides, metal oxide particles, and sol thereof Metal compound taken c) solvent A gate insulating film coating composition comprising: [Formula 1] In the formula of Formula 1, n is an integer from 10 to 1,000,000. [Formula 2] In the formula (2), R ₁ and R ₂ are each H or CH ₃ , n is an integer from 10 to 1,000,000. The method of claim 1, 5 to 40 parts by weight of the matrix polymer of a) 10 to 50 parts by weight of the metal compound of b); And 10 to 85 parts by weight of the solvent of c) Gate insulating film coating composition comprising a. The method of claim 1, The polyphosphazene polymer of a) iii) is prepared by the method comprising the step of solid-phase polymerization of hexachlorocyclotriphosphazene at a high temperature of 200 to 300 ℃. The method of claim 1, The polyphosphazene copolymer polymer of a) ii) is prepared by a method comprising the step of adding a methyl phenol substituted to the polyphosphazene polymer of a) i) and a catalyst and heat-polymerizing. The method of claim 4, wherein A gate insulating film coating composition wherein the polymerization is carried out for 12 to 48 hours at a temperature of 200 to 300 ℃. The method of claim 1, And the metal alkoxide of step b) is selected from the group consisting of silicon alkoxide, titanium alkoxide, zirconium alkoxide, barium alkoxide and aluminum alkoxide. The method of claim 1, And the metal oxide particles of step b) are selected from the group consisting of silica, titania, zirconia, and alumina. The method of claim 1, The metal alkoxide sol and the metal oxide sol of b) are added to each metal alkoxide or metal oxide so that the concentration of the metal alkoxide or metal oxide is 20 to 80% by weight, and 0.01 to 0.5% by weight based on the added water. A gate insulating film coating composition prepared by the method comprising the step of adding an acid catalyst of hydrolysis and condensation reaction. In the method of manufacturing a gate insulating film for a thin film transistor of a liquid crystal display device, a) iii) a polyphosphazene polymer represented by Formula 1 below; or To include a polymer which is a polyphosphazene copolymer represented by the formula (2) Is a matrix polymer; Ii) from the group consisting of metal alkoxides, metal oxide particles, and sols thereof Metal compound chosen Iii) solvent Blending and preparing a mixed coating solution; b) coating the mixed coating solution on a substrate to form a coating film; And c) heating and curing the coating film Method of manufacturing a gate insulating film comprising: [Formula 1] In the formula of Formula 1, n is an integer from 10 to 1,000,000. [Formula 2] In the formula (2), R ₁ and R ₂ are each H or CH ₃ , n is an integer from 10 to 1,000,000. The method of claim 9, A method for producing a gate insulating film further comprising aminopropylsiloxane in the solvent of a) iii).