KR100363273B1 - Photoresist composition for liquid crystal display circuit board - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoresist composition for liquid crystal display circuits used in the manufacture of fine circuits such as liquid crystal display circuits, semiconductor integrated circuits, etc., comprising a polymer resin, a photosensitive compound, and an organic solvent. In the composition, wherein the polymer resin is a novolak resin, the photosensitive compound is a diazide compound, the organic solvent comprises propylene glycol methyl etheracetate and methyl methoxy propionate (methylmethoxypropionate) A photoresist composition for a liquid crystal display device circuit is provided.

The photoresist composition for a liquid crystal display circuit of the present invention has excellent photosensitivity, residual film ratio, and circuit uniformity (CD uniformity), and excellent resolution, development contrast, adhesiveness, and solubility to strippers, thus making it easy to use in industrial fields. Not only can it be applied, but the amount of odor generated is small, which makes it possible to change the working environment well.

Description

Photoresist composition for liquid crystal display circuits {PHOTORESIST COMPOSITION FOR LIQUID CRYSTAL DISPLAY CIRCUIT BOARD}

[Industrial use]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to photoresist compositions for liquid crystal display circuits used in the manufacture of microcircuits such as liquid crystal display circuits and semiconductor integrated circuits. More particularly, the present invention relates to polymer resins, photosensitive compounds and organic solvents for forming photoresist films. It relates to a photoresist composition for a liquid crystal display circuit comprising.

[Prior art]

In order to form a fine circuit pattern such as a liquid crystal display circuit or a semiconductor integrated circuit, first, the photoresist composition for a liquid crystal display circuit is uniformly coated or coated on an insulating film or a conductive metal film formed on a substrate, and a mask having a predetermined shape is present. The photoresist composition for a liquid crystal display circuit coated under the light is exposed and developed to form a pattern of a desired shape. The metal film or the insulating film is etched using the patterned photoresist film as a mask, and then the remaining photoresist film is removed to form a fine circuit on the substrate. The photoresist composition for a liquid crystal display device circuit is classified into a negative type and a positive type according to the change in solubility of the exposed portion.

Practically important characteristics of the photoresist composition for a liquid crystal display circuit include ease of use such as photoresist speed, development contrast, resolution, adhesion to a substrate, residual film ratio, circuit uniformity, and human safety of the formed resist film. do.

The photosensitive speed refers to the speed at which the solubility of the photoresist for the liquid crystal display circuit is changed by exposure, which requires several exposures in order to generate a multi-pattern by an iterative process, or when light passes through a series of lenses and a monochromatic filter. This is particularly important for photoresist films that use light with reduced intensity, such as projection exposure techniques.

In particular, in order to reduce the long exposure time in the production line due to the large area of the substrate, which is a feature of the thin film transistor liquid crystal display device (hereinafter referred to as TFT-LCD), it is necessary to improve the photosensitive speed. Here, after spin-coating a photoresist for a liquid crystal display circuit to be used in a large area such as a TFT-LCD, the pin is used in a proximity type or the like during soft bake. There is a problem in that the thickness difference of the film due to the non-uniform variation of the temperature, which causes a non-uniform line width of the pattern when forming the final fine circuit pattern. In addition, since the photosensitive speed and the residual film ratio are inversely related, the fast residual film ratio tends to decrease.

The development contrast refers to the ratio of the film loss amount in the exposed part by the development and the film loss amount in the unexposed part. Typically, exposed substrates coated with a photoresist film are developed continuously until the coating at the exposed site is almost completely dissolved and removed, so the development contrast is simply determined by measuring the amount of film loss at the unexposed areas when the exposed coating site is completely removed. You can decide.

Photoresist film resolution refers to the ability of a resist film system to regenerate fine circuit lines into highly sensitive images depending on the spacing of the mask used to expose the resist film.

In various industrial uses, especially in the manufacture of liquid crystal display devices and semiconductor circuits, the photoresist film for liquid crystal display device circuits requires a resolution such that a pattern having a very thin line and a space area (1 μm or less) can be formed.

Most photoresist compositions for liquid crystal display circuits include a polymer resin, a photosensitive compound, and a solvent for forming a photoresist film. Many attempts have been made in the prior art to improve the photosensitivity, development contrast, resolution and human safety of photoresist compositions for liquid crystal display circuits.

For example, US Pat. No. 3,666,473 discloses the use of a mixture of two phenolformaldehyde novolac resins and typical photosensitive compounds, while US Pat. No. 4,115,128 discloses phenolic resins and naphthoquinones to increase photosensitivity. The addition of organic acid cyclic anhydrides to diazide photosensitizers is disclosed, and US Pat. No. 4,550,069 discloses propylene glycol alkyl ethers as solvents and novolak resins and o-quinonediazide photosensitive compounds in order to increase photosensitivity and improve human safety. The use of acetate is disclosed.

In particular, various solvents have been developed to improve physical properties and work stability of photoresist compositions for liquid crystal display circuits, and examples thereof include ethylene glycol monoethyl ether acetate, propylene glycol monoethyl ether acetate, and ethyl lactate. However, when ethylene glycol monoethyl ether acetate is used, serious side effects on human safety have been reported, and when propylene glycol monoethyl ether acetate is used, defects due to pin marks after baking process in a large area substrate such as TFT-LCD are reported. There is a problem that results, when using ethyl lactate has a disadvantage of poor adhesion of the composition to the substrate, difficult to uniform coating.

Therefore, each industrial process can be made without sacrificing any of the desirable properties of the photoresist composition for liquid crystal display circuits such as photosensitivity, residual film ratio, development contrast, resolution, polymer resin solubility, and circuit line width uniformity. There is a continuing need for suitable photoresist compositions for various liquid crystal display circuits.

The present invention has been made to solve the problems described above, the present invention is excellent in the photoresist film, residual film ratio, development contrast, resolution, circuit line width uniformity, and adhesion to the substrate of the prepared photoresist film, especially TFT- An object of the present invention is to provide a photoresist composition for a liquid crystal display circuit having a novel composition that can solve pin mark defects generated during the manufacture of a large area liquid crystal display circuit such as an LCD.

[Means for solving the problem]

In order to achieve the above object,

The present invention relates to a photoresist composition for a liquid crystal display circuit including a polymer resin, a photosensitive compound, and an organic solvent, wherein the polymer resin is a novolak resin, the photosensitive compound is a diazide compound, and the organic solvent is propylene. Provided is a photoresist composition for a liquid crystal display device circuit comprising glycol methyl ether acetate and methyl methoxypropionate.

The photoresist composition for a liquid crystal display device circuit preferably contains 10 to 25% by weight of the polymer resin, 3 to 10% by weight of the photosensitive compound, and 65 to 87% by weight of the organic solvent.

The photosensitive compound is 2,3,4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate and 2,3,4, -trihydroxybenzophenone-1,2 It is preferred to include naphthoquinonediazide-5-sulfonate.

2,3,4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate and 2,3,4, -trihydroxybenzophenone-1,2-naphtho The mixing ratio of quinonediazide-5-sulfonate is preferably 40 parts by weight: 60 parts by weight to 60 parts by weight: 40 parts by weight.

Propylene glycol methyl ether acetate (hereinafter referred to as PGMEA) and methylmethoxypropionate (hereinafter referred to as MMP), which are the organic solvents, are preferably used by mixing in a ratio of 60 to 95 parts by weight: 5 to 40 parts by weight.

The present invention also provides a photoresist film prepared using the photoresist composition for a liquid crystal display circuit.

Hereinafter, the present invention will be described in detail.

Polymer resins that can be used to prepare photoresist compositions for liquid crystal display circuits are well known in the art. The polymer of the present invention is a novolak resin, and the novolak resin is a polymer polymer synthesized by reacting an aromatic alcohol such as phenol, meta and / or paracresol with formaldehyde, and improves the performance of a photoresist for a liquid crystal display circuit. In order to remove a polymer, a medium molecule, a low molecule, etc. from said resin suitably, you may select and use the resin of the molecular weight suitable for a use.

In the present invention, it is preferable that the content of the polymer resin in the photoresist composition for the entire liquid crystal display circuit is 10 to 25% by weight, the photosensitive compound is 3 to 10% by weight, and the content of the solvent is 65 to 87% by weight. desirable. If the content of the polymer resin is less than 10% by weight, the viscosity is too low, there is a problem in the coating of the desired thickness, if the content exceeds 25% by weight is too high, there is a problem that the uniform coating of the substrate is difficult, If the content is less than 3% by weight, there is a problem due to the excessive decrease of the residual film rate while the photosensitive speed is too fast, and if the content exceeds 10% by weight, the photosensitive speed is too slow.

In addition, the diazide compound which is the photosensitive compound of the present invention is made by reacting a diazide compound such as polyhydroxy benzophenone, 1,2-naphthoquinone diazide, 2-diazo-1-naphthol-5-sulfonic acid, and the like. It can manufacture.

In the photoresist composition for a liquid crystal display circuit of the present invention, the photosensitive compound used is 2,3,4, prepared by esterifying trihydroxy benzophenone and 2-diazo-1-naphthol-5-sulfonic acid. 2,3 prepared by esterifying trihydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate with tetrahydroxy benzophenone and 2-diazo-1-naphthol-5-sulfonic acid , 4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate is preferably 40 parts by weight: 60 parts by weight to 60 parts by weight: 40 parts by weight, more preferably 50 parts by weight: 50 parts by weight, compared with the use of each photosensitive compound alone, it can be seen that the mixed film photosensitive compound has the highest residual film ratio at the same level of photosensitive speed.

In the photoresist composition for a liquid crystal display circuit of the present invention, PGMEA and MMP used as an organic solvent are preferably used in a mixture of 60 to 95 parts by weight: 5 to 40 parts by weight. If the amount of PGMEA exceeds the above range, there is a problem that the thickness of the film tends to change with respect to the temperature change during soft bake, and if the amount of MMP exceeds the range, the residual film ratio is lowered compared to the increase in the photosensitive speed. There is a problem that is worse.

Improved performance according to the characteristics of individual processes by coating the substrate with additives such as colorants, dyes, anti-scratches, plasticizers, adhesion promoters, speed enhancers, surfactants, etc. to the photoresist composition for the liquid crystal display device circuit manufactured by the present invention You can also promote

The photoresist composition for a liquid crystal display circuit manufactured as described above is used in a semiconductor manufacturing process as follows.

The photoresist composition for a liquid crystal display circuit is applied to a substrate in a conventional manner including dipping, spraying, rotating, and spin coating. For example, in the case of spin coating, a coating having a desired thickness can be formed by appropriately changing the solids content of the photoresist solution for a liquid crystal display circuit according to the type and method of the spinning device.

The substrate includes silicon, aluminum, silicon dioxide, doped silicon dioxide, silicon nitride, tantalum, copper, polysilicon, ceramics, aluminum / copper mixtures, and various polymerizable resins.

The photoresist composition for a liquid crystal display circuit coated on the substrate by the above method is heated to a temperature of 20 to 100 ° C. This is called a soft bake process. This heat treatment is performed to evaporate the solvent without pyrolyzing the solid component in the photoresist composition for the liquid crystal display circuit. In general, it is preferable to minimize the concentration of the solvent through a soft bake process. Therefore, the heat treatment is performed until most of the solvent is evaporated so that a thin coating film of the photoresist composition for a liquid crystal display circuit having a thickness of 2 μm or less remains on the substrate. do.

Next, the substrate on which the photoresist film is formed is exposed to light, especially ultraviolet rays, using a suitable mask, template, or the like to form a pattern of a desired shape. In this manner, the exposed substrate is sufficiently immersed in the alkaline developing aqueous solution, and then left until all or almost all of the photoresist film at the portion exposed to light is dissolved. Suitable developing aqueous solutions include aqueous solutions containing alkali hydroxide, ammonium hydroxide or tetramethylammonium hydroxide.

The exposed part may be removed by removing the substrate from the developer and then heat-treated again to improve adhesion and chemical resistance of the photoresist film, which is generally referred to as a hard bake process. This heat treatment is carried out at a temperature below the softening point of the photoresist film, preferably at a temperature of 90 to 140 ° C.

The developed substrate is treated with a corrosion solution or a gas plasma to treat the exposed substrate portion, wherein the unexposed portion of the substrate is protected by the photoresist film. After treating the substrate in this manner, a fine circuit pattern is formed on the substrate by removing the photoresist film with an appropriate stripper.

The present invention will be described in more detail with reference to the following examples and comparative examples. However, the following examples are for illustrating the present invention and the present invention is not limited by the following examples.

[Examples 1 to 4 and Comparative Examples 1 to 2]

76 g of a photosensitive agent and 76 g of a resin were added to the composition of Examples and Comparative Examples shown in Table 1 below, and stirred at 40 rpm at room temperature to prepare a photoresist composition for a liquid crystal display circuit. The prepared photoresist composition for a liquid crystal display circuit was dropped on a glass substrate of 0.7 T (thickness: 0.7 mm), rotated at a constant rotational speed, and then heated and dried at 115 ° C. for 90 seconds to obtain a thickness of 1.50 μm. A film film was formed. After mounting a mask having a predetermined shape on the film film, and irradiated with ultraviolet light, and then immersed in a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 60 seconds, the portion exposed to ultraviolet light was removed to form a photoresist pattern.

end. Photospeed and Remnant Rate

The photosensitivity was determined by measuring the energy in which the film completely melted under a certain developing condition according to the exposure energy. After performing the soft bake at 110 ° C., the exposure and the developing were performed. The residual film ratio was calculated by calculation, and the difference in thickness before and after development that can represent the measurement result is shown in Table 1 below.

[Equation 1]

Residual Ratio = (Residual Thickness / Initial Film Thickness)

The initial film thickness here is the sum of the loss thickness and the residual film thickness.

As can be seen from the results in Table 1, the photosensitive energy of the photoresist film prepared by the photoresist composition for a liquid crystal display circuit of the present invention was converted into the photoresist film prepared by the photoresist composition for a conventional liquid crystal display device circuit. It can be seen that the residual film ratio has a high value at an equivalent level when compared with the photosensitive energy.

In addition, the photoresist film manufactured by the photoresist composition for a liquid crystal display device circuit of the present invention leaves more residual film of the photoresist for the liquid crystal display device circuit than the photoresist film prepared by the photoresist composition for a conventional liquid crystal display device circuit. It can be seen that the physical properties of the photoresist film are superior to the conventional ones.

I. Pin mark test

In the case of a large-area TFT-LCD substrate, in order to prevent particle generation, a proximity type is mainly used instead of a contact type during soft baking. In this case, a fin or the like is used to support the gap between the substrate and the hot plate, and a change in the film thickness occurs due to a temperature difference between a portion directly contacting the fin and a portion not.

As a result, there is a difference in the line width of the microcircuit, which is a result of the line width of the metal layer on the transparent electrode in the case of the TFT-LCD, and the brightness of the screen is changed. This is a problem related to the packing density in the photoresist film and is affected by the type and content of the solvent.

For the pin mark test according to the progress of the process, the film thickness at 110 ° C. was 1.5 μm, followed by a soft bake and the pin mark state of the substrate according to the pin mark in Table 1 below.

division Photosensitizer Resin menstruum Photosensitive speed (mJ / cm ² ) Thickness difference before and after development (Dev. Loss) Pin Mark Example 1 A + B (50:50) a PGMEA / MMP (60/40) 14.55 580 O Example 2 A + B (50:50) a PGMEA / MMP (70/30) 14.48 520 O Example 3 A + B (55:45) a PGMEA / MMP (80/20) 14.65 480 O Example 4 A + B (60:40) a PGMEA / MMP (95/5) 15.72 408 △ Comparative Example 1 A a PGMEA 15.88 1076 × Comparative Example 2 A a PGMEA / MMP (95/5) 16.27 1566 △

A: 2,3,4,4'-tetrahydroxybenzophenone-1,2-naphthoquinone diazide-5-sulfo

Nate

B: 2,3,4, -trihydroxybenzophenone-1,2-naphthoquinone diazide-5-sulfonate

RESIN a: (m-cresol / p-cresol = 4/6 mixed)

PGMEA: Propylene Glycol Methyl Ether Acetate

MMP: Methylmethoxypropionate

O: no pin mark observed

Δ: Pin mark is observed faintly

×: Pin mark is clearly observed

As described above, the photoresist composition for a liquid crystal display device circuit of the present invention has excellent photosensitivity, residual film ratio, and circuit line width uniformity, and is excellent in resolution, developing contrast, adhesion, and stripper so that it is easy to use in actual industrial sites. Not only can it be applied, but also the amount of odor generated is small, which can change the working environment satisfactorily.

Claims (6)

(correction) (a) 10 to 25% by weight novolak resin; (b) 2,3,4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate and 2,3,4-trihydroxybenzophenone-1,2-naph 40 parts by weight of toquinonediazide-5-sulfonate: 60 parts by weight to 60 parts by weight: 3 to 6% by weight of a mixture of 40 parts by weight; And (c) 65 to 87% by weight of an organic solvent having a mixing ratio of propylene glycol methyl ether acetate and methyl methoxy propionate 60 parts by weight: 40 parts by weight to 95 parts by weight: 5 parts by weight Photoresist composition for a liquid crystal display device circuit comprising a. (delete) (delete) (delete) (delete) A photoresist film prepared by using the photoresist composition for liquid crystal display circuit of claim 1.