TWI397767B - Photoresist composition - Google Patents

Description

Photoresist composition

The present invention relates to a photoresist composition for manufacturing a microcircuit of a liquid crystal display element, a semiconductor integrated circuit, or the like, and more particularly to a component which can improve the fluidity of a photoresist composition by introduction. A photoresist composition having excellent uniformity and adhesion pattern is obtained.

In order to form a pattern of a fine circuit such as a circuit of a liquid crystal display element or a semiconductor integrated circuit, first, a photoresist composition is uniformly applied onto an insulating film or a conductive metal film on a substrate. Then, the photoresist composition film is exposed and developed by using a predetermined shape mask to form a pattern of a predetermined shape. Thereafter, the metal film or the insulating film is etched using a photomask to remove the residual photoresist film, and a fine circuit is formed on the substrate. The coating process is a spin coating method or a slit coating method.

Generally, the photoresist composition contains a polymer resin, a photosensitive compound, and a solvent. Up to now, many efforts have been made to improve the coating uniformity, speed, development contrast, resolution, adhesion to the substrate, residual film ratio, and circuit line width of the photoresist film formed by using the photoresist composition. CD uniformity and human safety.

For example, U.S. Patent No. 3,664,473 discloses a mixture of two phenolformaldehyde novolak resins and a typical photosensitive compound, and U.S. Patent No. 4,115,128 discloses the addition of a phenolic resin and a naphthoquinone diazide for increasing the speed of photosensitivity. The composition of the organic acid cyclic anhydride is added to the photosensitizer. U.S. Patent No. 4,505,069 discloses the use of novolac resin, o-quinone diazide for increasing the speed of photosensitivity and improving human safety. A compound and a photoresist composition using propylene glycol alkyl ether acetate as a solvent.

However, it is still necessary to not lose the speed, residual film rate, Remain Film Thickness uniformity, development contrast, resolution, solubility of polymer resin, adhesion to substrate, and circuit line. At the same time as any of the characteristics of the photoresist composition such as wide uniformity, it is suitable for a variety of photoresist compositions for various industrial projects.

The present invention has been made in view of the above problems, and an object thereof is to provide an improvement in a photosensitive speed, a residual film ratio, a development contrast, a resolution, a solubility of a polymer resin, a bonding force with a substrate, and a uniform line width of a photoresist film. A CD uniformity photoresist composition.

An object of the present invention is to provide a photoresist composition which is excellent in uniformity and formation effect of a pattern after a hard bake process and which is excellent in dry etching and wet etching.

Another object of the present invention is to provide a liquid crystal display element or a semiconductor element manufactured using the above-described photoresist composition.

In order to achieve the above object, the present invention provides a photoresist comprising (a) a novolac resin, (b) a diazo photosensitive compound, (c) a fluidity improving agent, (d) a sensitivity improving agent, and (e) an organic solvent. Agent composition.

Moreover, the present invention provides a liquid crystal display element or a semiconductor element manufactured using the above-described photoresist composition.

Hereinafter, the present invention will be described in detail.

The present invention relates to a photoresist composition which uses a fluidity improver and a sensitivity enhancer to improve the fluidity of a photoresist film in a hard baking process.

The photoresist composition according to the present invention comprises (a) a novolak resin, (b) a diazo photosensitive compound, (c) a fluidity improver, (d) a sensitivity improving agent, and (e) an organic solvent.

In the photoresist composition according to the present invention, (a) the novolak resin is a polymer obtained by reacting an aromatic alcohol such as m-cresol or p-cresol with formaldehyde, and the weight average molecular weight thereof is preferably 2,000~10,000.

The physical properties such as the photospeed and the residual film ratio of the above (a) novolak resin differ depending on the mixing ratio of m-cresol and p-cresol. Specifically, the above (a) novolac resin preferably has an optimum content ratio of cresol and p-cresol of 30 to 70 parts by weight and 70 to 30 parts by weight, respectively. If the content of m-cresol exceeds the above range, the photospeed will be accelerated, and the residual film ratio will be lowered. When the content of p-cresol exceeds the above range, the photospeed will be slow.

The content of the above (a) novolac resin in the photoresist composition is preferably 5 wt% or more for easy application to a desired thickness, and is preferably 30 wt% for uniform coating. %the following.

The present invention can be produced by reacting a compound such as polyhydroxybenzophenone, 1,2-naphthoquinonediazide or 2-diazo-1-naphthol-5-sulfonic acid. (b) a diazo photosensitive compound in the photoresist composition concerned.

For example, as the (b) diazonic photosensitive compound, the following two compounds may be used singly or in combination: 2,3,4-trihydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate or 2,3,4,4'-tetrahydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate; wherein the 2,3,4-trihydroxybenzophenone-1,2 - Diazonaphthoquinone-5-sulfonate is formed by esterification of trihydroxybenzophenone with 2-diazo-1-naphthol-5-sulfonic acid; the 2,3,4,4' -Tetrahydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate is esterified by tetrahydroxybenzophenone with 2-diazo-1-naphthol-5-sulfonic acid form. More preferably, 2,3,4-trihydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1, The 2-diazonaphthoquinone-5-sulfonate is used in a mixture of 40 to 60 parts by weight and 60 to 40 parts by weight, respectively.

In order to maintain the appropriate photospeed of the (b) diazonium-based photosensitive compound, the content in the photoresist composition is preferably from 2 to 10% by weight.

In particular, in order to maintain fluidity in a hard bake process and to optimize the formation of a pattern, the photoresist composition according to the present invention contains (c) a fluidity improver.

In the above (c) fluidity improving agent, ethylene glycols and pyrrolidone having a boiling point of 180 ° C or higher are preferably used, and typical examples thereof are dipropylene glycol monomethyl ether and 2,2',4-trimethyl-1. , 3-, 2-', 4-trimethyl-1,3-pentanediol monoisobutylate, 1-(2-hydroxyethyl)-2-pyrrolidone (1-(2-hydroxyethyl)- 2-pyrrolidone) and γ-butyrolactone.

Further, in order to sufficiently exhibit the fluidity effect, the content of the above (c) fluidity improving agent in the photoresist composition is preferably 0.5% by weight or more, and the addition amount is preferably the highest in order to improve the residual film ratio and the coating property. It is 5 wt% or less.

In the photoresist composition according to the present invention, the purpose of using (d) the sensitivity improving agent is to improve the sensitivity and the effect of pattern formation in the hard baking step.

The above (d) sensitivity improving agent is preferably a polyhydroxy compound having a phenolic hydroxyl functional group and having a weight average molecular weight of less than 500. For example, it can be used, from 2,3,4-trihydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3,4,3',4',5-hexahydroxy Benzophenone, acetone-biphenyltriol condensate, 4,4-[1-[4-[1,(1,4-hydroxyphenyl)-1-methylethyl]phenyl]ethylene Bisphenol (4,4-[1-[4-[1,(1,4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol) and 4,4'-[2-hydroxyphenyl] More than one compound selected from the group of [4,4'-[2-hydroxyphenyl]methylene]bis[2,6-dimethylphenol].

In order to sufficiently exhibit the sensitivity enhancing effect, the content of the above (d) sensitivity improving agent in the resist composition is preferably 0.1 wt% or more, and in order to prevent a sharp drop in the residual film ratio, the amount of addition is preferably 10 wt. %the following.

The photoresist composition according to the present invention contains a balance of an organic solvent (e) which is at least one selected from the group consisting of propylene glycol methyl ether acetate (PGMEA) and lactic acid. Ethyl ester (EL), 2-methoxy ethylacetate, methyl 3-methoxy propionate (MMP) and propylene glycol monomethyl ether (PGME), most PGMEA and MMP are preferably mixed in a mixing ratio of 70 to 90 parts by weight and 30 to 10 parts by weight.

Further, the photoresist composition according to the present invention may be further added as needed, and one or more additives selected from the group consisting of a colorant, a coloring agent, a streaking inhibitor, a plasticizer, a tackifier, an accelerator, and a surfactant, The substrate is coated to improve performance in accordance with individual process characteristics.

Moreover, the present invention enables the fabrication of a semiconductor element using the above-described photoresist composition. For example, some of the semiconductor elements can be used in the manufacturing process of the liquid crystal display element circuit as follows.

First, the photoresist composition according to the present invention is applied onto a substrate by a usual coating method including a dip coating method, a spray method, a roll coating method, and a spin coating method. For example, when a spin coating method is used, a coating layer of a desired thickness can be formed by appropriately changing the solid content in the photoresist solution according to a spinning device and a spinning method.

The substrate is preferably selected from the group consisting of ruthenium, aluminum, indium tin oxide (ITO), indium zinc oxide (IZO), molybdenum, ruthenium dioxide, doped ruthenium dioxide, tantalum nitride, ruthenium, copper, polycrystalline germanium. , ceramics, copper/aluminum mixtures and polymeric resins.

In order to remove the residual solvent of the photoresist composition coated on the substrate by the above method, a vacuum drying step of maintaining a predetermined time under a reduced pressure condition of normal pressure or lower can be carried out. At this time, the larger the substrate is, the stronger the decompression condition is. Therefore, the pattern after the development process and the hard baking process may be deformed or the uniformity of the central portion and the edge portion pattern of the substrate may be lowered.

Next, a soft bake process of heat treatment at a temperature of 20 to 130 ° C can be carried out. The purpose of the heat treatment is to evaporate the solvent in the case where the solid component in the photoresist composition is not thermally decomposed. It is preferable to minimize the concentration of the solvent by a soft baking process until the thickness of the photoresist film on the substrate reaches 2 μm or less.

The substrate on which the photoresist film is formed is then exposed, particularly to ultraviolet light, using a suitable mask or stencil to form a pattern of the desired shape. Thereafter, the substrate exposed by the above steps is sufficiently immersed in the alkaline developing aqueous solution until all or most of the photoresist film at the exposed portion is dissolved. Among them, the aqueous developing solution preferably uses an aqueous solution containing an alkali hydroxide, ammonium hydroxide or tetramethylammonium hydroxide.

The substrate on which the exposed portion is dissolved and removed is taken out from the developer, and then heat-treated by a hard baking step to improve the adhesion and chemical resistance of the photoresist film. This heat treatment is preferably carried out at a temperature below the softening point of the photoresist film, i.e., at a temperature ranging from 90 to 140 °C.

The substrate which has been developed as described above is treated with an etching solution or a gaseous plasma, and at this time, only the exposed portion of the substrate is treated, and the exposed portion of the substrate is protected by the photoresist film. After the substrate is processed in this manner, the photoresist film is removed by a suitable release agent, whereby a fine circuit pattern can be formed on the substrate.

Hereinafter, examples and comparative examples which are helpful for understanding the present invention will be exemplified. However, the following examples are merely examples of the invention, and the scope of the invention is not limited to the following examples.

[Examples] Example 1

20 g of novolac resin (weight average molecular weight: 4,325) was uniformly mixed, and the weight ratio of m-cresol to p-cresol was 4:6; 4 g of diazo-based photosensitive compound was 50:50 by weight. Ratio of 2,3,4-trihydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1,2- Diazonaphthoquinone-5-sulfonate; 2.8 g of fluidity improver, which is dipropylene glycol monomethyl ether (DPGME); 2.8 g of sensitivity enhancer, which is 4,4-[1-[4-[ 1, (1,4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol; 60 g of an organic solvent which is propylene glycol methyl ether acetate (PGMEA) to produce light Resist composition.

Example 2

20 g of novolac resin (weight average molecular weight: 4,325) was uniformly mixed, and the weight ratio of m-cresol to p-cresol was 4:6; 4 g of diazo-based photosensitive compound was 50:50 by weight. Ratio of 2,3,4-trihydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1,2- Diazonaphthoquinone-5-sulfonate; 2.8 g of fluidity improver, 2,2',4-trimethyl-1,3-pentanediol monoisobutyl ester (TMPMB); 2.8 g Sensitivity enhancer which is 4,4-[1-[4-[1-(1,4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol; 60 g An organic solvent which is propylene glycol methyl ether acetate (PGMEA) to produce a photoresist composition.

Example 3

20 g of novolac resin (weight average molecular weight: 4,325) was uniformly mixed, and the weight ratio of m-cresol to p-cresol was 4:6; 4 g of diazo-based photosensitive compound was 50:50 by weight. Ratio of 2,3,4-trihydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1,2- Diazonaphthoquinone-5-sulfonate; 2.8 g of fluidity improver, which is 1-(2-hydroxyethyl)-2-pyrrolidone; 2.8 g of sensitivity enhancer, which is 4,4-[1 -[4-[1-(1,4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol; 60 g of an organic solvent which is propylene glycol methyl ether acetate (PGMEA ) to thereby produce a photoresist composition.

Example 4

20 g of novolac resin (weight average molecular weight: 4,325) was uniformly mixed, and the weight ratio of m-cresol to p-cresol was 4:6; 4 g of diazo-based photosensitive compound was 50:50 by weight. Ratio of 2,3,4-trihydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1,2- Diazonaphthoquinone-5-sulfonate; 2.8 g of fluidity improver, which is γ-butyrolactone (GBL); 2.8 g of sensitivity enhancer, which is 4,4-[1-[4-[ 1, (1,4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol; 60 g of an organic solvent which is propylene glycol methyl ether acetate (PGMEA) to produce light Resist composition.

[Comparative example] Comparative example 1

20 g of novolac resin (weight average molecular weight: 4,325) was uniformly mixed, and the weight ratio of m-cresol to p-cresol was 4:6; 4 g of diazo-based photosensitive compound was 50:50 by weight. Ratio of 2,3,4-trihydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1,2- Diazonaphthoquinone-5-sulfonate; 60 g of an organic solvent which is propylene glycol methyl ether acetate (PGMEA) to produce a photoresist composition.

Comparative example 2

20 g of novolac resin (weight average molecular weight: 4,325) was uniformly mixed, and the weight ratio of m-cresol to p-cresol was 4:6; 4 g of diazo-based photosensitive compound was 50:50 by weight. Ratio of 2,3,4-trihydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1,2- Diazonaphthoquinone-5-sulfonate; 2.8 g sensitivity enhancer, which is 4,4-[1-[4-[1-(1,4-hydroxyphenyl)-1-methylethyl] Phenyl]ethylidene]bisphenol; 60 g of an organic solvent which is propylene glycol methyl ether acetate (PGMEA) to produce a photoresist composition.

In Table 1, the composition of the photoresist composition manufactured in the above Examples 1 to 4 and Comparative Examples 1 to 2 is shown in units of grams (g).

[Experimental example]

The following experiment was conducted on the photoresist compositions produced in the above Examples 1 to 4 and Comparative Examples 1 to 2, and the results of the experiment are shown in Table 2.

Each of the photoresist compositions produced in the above Examples 1 to 4 and Comparative Examples 1 to 2 was spin-coated on a 0.7 T (thickness: 0.7 mm) glass substrate at a constant speed, and then at 0.1 Torr. Under the following conditions (Torr), vacuum drying was performed for 60 seconds, and the substrate was dried by heating at a temperature of 110 ° C for 90 seconds to form a photoresist film having a thickness of 1.50 μm.

Next, the thickness uniformity of the photoresist film was measured, and it was exposed to ultraviolet light having a wavelength of 365 to 435 nm using a photomask, and then immersed in an aqueous solution containing tetramethylammonium hydroxide for 60 seconds for development. Make it patterned.

After the formed pattern was subjected to a hard baking (130 ° C) process, the effect of pattern formation was evaluated by a scanning electron microscope.

1) Photospeed and residual film rate Initial film thickness = loss thickness + residual film thickness Residual film rate = (residual film thickness / initial film thickness)

According to the change of the exposure energy, the energy of the film layer is completely dissolved under a certain development condition, thereby obtaining the photospeed, and the soft baking is performed at a temperature of 110 ° C to expose and develop the residue. The film ratio and the difference in thickness before and after development which can reflect the result were measured.

2) Heat resistance With respect to heat resistance, after hard baking for 90 seconds under conditions of a temperature of 130 ° C, the effect of pattern formation was confirmed by a scanning electron microscope.

3) Adhesiveness After forming a pattern (fine line width) on a glass substrate coated with molybdenum (Mo), the molybdenum layer at the exposed portion is removed, treated with an etching solution, and etched by measuring the etching solution without exposure. The etched thickness of the molybdenum layer was tested for adhesion.

As shown in the above Table 2, the photoresist film produced by using the photoresist compositions of Examples 1 to 4 according to the present invention and the photoresist film produced by the photoresist compositions of Comparative Examples 1 to 2 were used. The photospeed, residual film rate and formation effect are more excellent.

The photoresist composition according to the present invention prevents the pattern deformation caused by vacuum drying and improves the uniformity of the pattern by using the fluidity improving agent and the sensitivity improving agent, and has a photosensitive speed, a residual film rate, and development. Contrast, resolution, solubility of polymer resin, adhesion to substrate, and uniformity of circuit line width are excellent. Therefore, it is suitable for industrial applications. In the case of mass production, the production environment can be effectively changed due to the effects of saving usage and shortening the mass production time.

Claims (9)

A photoresist composition comprising: a) a novolak resin; b) a diazo photosensitive compound; c) a fluidity improver; d) a sensitivity enhancer; and e) an organic solvent; wherein the fluidity improver It is at least one selected from the group consisting of dipropylene glycol monomethyl ether, 2,2',4-trimethyl-1,3-pentanediol monoisobutyl ester, and 1-(2- Hydroxyethyl)-2-pyrrolidone. The photoresist composition according to claim 1, comprising: a) 5 to 30 wt% of the novolak resin; b) 2 to 10 wt% of the diazo photosensitive compound; c) 0.5 ~5 wt% of the fluidity improver; d) 0.1 to 10 wt% of the sensitivity enhancer; and e) the balance of the organic solvent. The photoresist composition according to claim 1, wherein the novolac resin is obtained by reacting m-cresol with p-cresol, and the ratio by weight of the m-cresol to p-cresol is 30 70 parts by weight and 70 to 30 parts by weight, and its weight average molecular weight is 2,000 to 10,000. The photoresist composition according to claim 1, wherein the diazo photosensitive compound comprises 40 to 60 parts by weight and 60 to 40 parts by weight of 2,3,4-three by weight, respectively. Hydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonic acid ester. The photoresist composition according to claim 1, wherein the sensitivity enhancer is at least one selected from the group consisting of 2,3,4-trihydroxybenzophenone, 2 , 3,4,4'-tetrahydroxybenzophenone, 2,3,4,3',4',5-hexahydroxybenzophenone, acetone-biphenyltriol condensate, 4,4-[ 1-[4-[1,(1,4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol and 4,4'-[2-hydroxyphenyl]methylene ] bis[2,6-dimethylphenol]. The photoresist composition according to claim 1, wherein the organic solvent is at least one selected from the group consisting of propylene glycol methyl ether acetate, ethyl lactate, and 2-methoxy Ethyl acetate, methyl 3-methoxypropionate and propylene glycol monomethyl ether. The photoresist composition according to claim 1, further comprising at least one selected from the group consisting of a coloring agent, a coloring agent, a streaking inhibitor, a plasticizer, and a tackifier. , accelerators and surfactants. A semiconductor device which is produced by using the photoresist composition according to any one of claims 1 to 7. A liquid crystal display device which is produced by using the photoresist composition according to any one of claims 1 to 7.