KR20120007124A - A positive photoresist composition - Google Patents

Abstract

PURPOSE: A positive photo-resist composition containing hyper-branched polyester oligomer containing plenty of hydropholic groups is provided to easily eliminate photo-resist after an etching process and to overcome resist residue related problems. CONSTITUTION: A positive photo-resist composition includes 10-20 parts by weight of a photo-sensitive agent, 0.1-15 parts by weight of polyester oligomer, and 50-200 parts by weight of a solvent based on 100 parts by weight of an alkali-soluble resin. The alkali-soluble resin is a novolack resin. The polyester oligomer is hyper-branched and contains hydrophobic groups on the end part. The weight average molecular weight of the novolak resin is between 2,000 and 50,000 by being converted into polystyrene. The photo-sensitive agent is the ester compound of a phenolic compound with a hydroxyl group and a quinonediazide sulfonic acid compound.

Description

Positive Photoresist Composition

The present invention relates to a positive photoresist composition, and more particularly, to a positive photoresist composition comprising an alkali-soluble resin, a photosensitive agent, a highly branched polyester oligomer containing a hydrophilic group at the end and a solvent.

In general, photoresist is a photosensitive film used to transfer an image to a substrate, which photoresist may be positive- or negative-functional. For most negative-functional photoresists, portions of the coating layer exposed to activating radiation polymerize or crosslink by the reaction of the photoactive compounds with the polymerizable reagents of the photoresist composition. As a result, the exposed coating portion is less soluble in the developer than the unexposed portion.

In the case of positive-functional photoresists, the exposed portions are more soluble in the developer, while the unexposed areas remain relatively less soluble in the developer.

Here, as a positive photoresist composition, a composition containing a binder resin soluble in an alkaline developer such as resol or cresol novolak resin and a dissolution inhibitor having a quinonediazide group is suitable, and such a composition is g-ray, h-ray, and i-ray. It is widely used in photolithography using a light source such as. Such photolithography technology has been widely used in the field of semiconductor and liquid crystal display device manufacturing because it has the advantage of forming a photoresist pattern having excellent resolution and shape at a relatively low cost.

Recently, due to the increase in size of glass due to the increase in demand for LCD panels, a photoresist composition suitable for yield improvement and quality enhancement is required. In terms of the process, the performance of the photoresist composition is also changed with the change from the 5 mask process to the 4 mask process.

The photoresist composition currently used in the four mask process is known to cause a problem of narrowing the channel part because the pattern flows when the heat is applied to 125 ° C. or higher during the baking process to form a low angle profile. In order to solve this problem, a high molecular weight resin is introduced into the photoresist, or a high heat resistant material is added to enhance heat resistance, and a resin containing carboxylic acid is added to maintain the dissolution rate of the resin in the developer. This is done.

However, this method enhances the heat resistance while lowering the residual film ratio of the photoresist and reducing the developing speed of the non-exposed areas where the pattern remains, leaving a residue. Therefore, it is difficult to obtain a pattern that allows the process to proceed with this method.

In addition, although a technique of including a dendrimer in a conventional negative photoresist is known, this remains a problem in that there is a reactor that is not hydrophilic and an addition reaction occurs to cross-cure.

Therefore, in order to solve the above problems, the present invention has been studied for a positive photoresist composition excellent in residual film ratio, developability, and peelability.

Accordingly, the present invention is to solve the above problems, an object of the present invention by facilitating the penetration of the developer and the stripping solution which is a hydrophilic liquid including a hyperbranched polyester oligomer containing a large amount of hydrophilic groups, It is to solve the resist residue problem and to provide a positive photoresist composition having excellent developability and peeling properties.

In order to solve the above object, the present invention provides a positive photoresist composition comprising an alkali-soluble resin, a photosensitive agent, a hyperbranched polyester oligomer containing a hydrophilic group at the end and a solvent.

The positive photoresist composition of the present invention contains a certain amount of a hyperbranched polyester oligomer containing a large amount of hydrophilic groups to facilitate the penetration of the developer and the stripping solution which is a hydrophilic liquid, thereby solving the problem of resist residues, and removing the photoresist after etching. The resist can be easily removed and has excellent developability and peeling characteristics.

The present invention is a positive photoresist composition comprising an alkali-soluble resin, a photosensitive agent, a hyperbranched polyester oligomer containing a large amount of hydrophilic groups at the end and a solvent, and more specifically, the photosensitive agent 10 to 100 parts by weight of the alkali-soluble resin. It is a positive photoresist composition comprising 20 parts by weight, 0.1 to 15 parts by weight of a hyperbranched polyester oligomer containing a hydrophilic group at the end and 50 to 200 parts by weight of a solvent .

At this time, the alkali-soluble resin is preferably a novolak resin, and not limited to this, can be used as long as it is a conventional one used in this field.

Herein, the novolak resin may be obtained by addition-condensation reaction between a phenol compound and an aldehyde compound, and is carried out by a conventional method in the presence of an acid catalyst.

In addition, the addition-condensation reaction is carried out in a suitable solvent or in bulk, and reacts at 60 to 250 ° C. for 2 to 30 hours.

The phenolic compounds include phenol, o-, m- and p-cresol, 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, 2,3,5-trimethylphenol, 4 t-butylphenol, 2-t-butylphenol, 3-t-butylphenol, 3-ethylphenol, 2-ethylphenol, 4-ethylphenol, 3-methyl-6-t-butylphenol, 4-methyl- At least one selected from the group consisting of 2-t-butylphenol, 2-naphthol, 1,3-dihydroxynaphthalene, 1,7-dihydroxynaphthalene and 1,5-dihydroxynaphthalene. It is preferable.

In addition, the aldehyde compounds are formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenylaldehyde, α- and β-phenylpropyl aldehyde, o-, m- and p-hydroxybenzaldehyde, glutaraldehyde, glycide It is preferable that it is 1 type, or 2 or more types of mixtures chosen from the group which consists of oxal, o-, and p-methylbenzaldehyde.

Here, the acid catalyst may be an organic acid such as oxalic acid, formic acid, trichloroacetic acid, p-toluenesulfonic acid, or the like; Inorganic acids including hydrochloric acid, sulfuric acid, perchloric acid, phosphoric acid; And it is preferable that it is 1 type, or 2 or more types chosen from the group which consists of a divalent metal salt containing zinc acetate and magnesium acetate.

In addition, the weight average molecular weight of the novolak resin produced by the addition-condensation reaction is preferably 2,000 to 50,000 in terms of polystyrene.

It is preferable that the said photosensitizer is an ester compound of the phenolic compound and quinonediazide sulfonic-acid compound which have a hydroxyl group.

At this time, the phenolic compound having a hydroxy group is 2,3,4,4'-tetrahydroxy benzophenone, trihydroxy benzophenone, 2,3,4-trihydroxy benzophenone, 2,3,4,4 -Tetrahydroxy benzophenone, 2,3,4,2,4-pentahydroxy benzophenone, tris 4-hydroxy phenylmethane, 1,3,5-tris 4-hydroxy a-dimethylbenzylbenzene, 1, 1-bis-4-hydroxyphenyl-1-4-1-4-hydroxyphenyl 1-methylethyl phenyl ethane, 2- (3,4-dihydroxyphenyl) -2- (4-hydroxyphenyl) It is preferable that it is 1 type, or 2 or more types chosen from the group which consists of propane.

Preferably, the quinonediazide sulfonic acid compound is o-quinonediazide sulfonic acid, and the o-quinonediazide sulfonic acid is 1,2-naphthoquinonediazide-5-sulfonic acid, 1,2-naphthoquinonediazide- It may be one kind or a mixture of two or more kinds selected from the group consisting of 4-sulfonic acid, 1,2-benzoquinonediazide-4-sulfonic acid and derivatives thereof.

Specific examples of the ester compound of the phenolic compound having a hydroxy group and the quinonediazide sulfonic acid compound include phenolic polyhydroxy compounds having at least three hydroxy groups, 1,2-naphthoquinonediazide-5-sulfonic acid, Preference is given to ester compounds of 1,2-naphthoquinonediazide-4-sulfonic acid or 1,2-benzoquinonediazide-4-sulfonic acid.

In addition, the manufacturing method of the ester compound of the phenolic compound and quinonediazide sulfonic-acid compound which has the said hydroxyl group is as follows. The ester compound can be obtained by reacting the phenolic compound having the hydroxy group with o-quinonediazidesulfonyl halide in the presence of a base such as triethylamine in a solvent such as toluene or heptanol. After completion of the reaction, suitable workup can be carried out to separate the desired quinonediazidesulfonic acid ester. Such suitable post-treatments include, for example, a method of mixing a reactant with water to precipitate a desired compound, filtering and drying to obtain a powdery product; The reaction is treated with a resist solvent such as 2-heptanone, washed with water, phase separated, and the solvent is removed by distillation or equilibrium flash distillation to obtain a product in the form of a solution in a resist solvent. The equilibrium flash distillation refers to a kind of continuous distillation that distills a portion of the liquid mixture and separates the vapor into a liquid phase when equilibrium is achieved by bringing the generated vapor into sufficient contact with the liquid phase. The equilibrium flash distillation has a very good evaporation rate, evaporation takes place in an instant, and the equilibrium between the vapor and the liquid phase is rapid, which is suitable for the concentration of the thermosensitive material.

The photosensitive agent is preferably included in 10 to 20 parts by weight based on 100 parts by weight of the alkali-soluble resin.

At this time, if the photosensitive agent is less than the above-described range, the pattern is not formed, the problem is that most of the resist is dissolved, if the above-described range is a problem that the sensitivity is lowered and only the upper part of the pattern is excessively large.

In addition, the highly branched polyester oligomer containing a hydrophilic group at the terminal is a compound in which the highly branched polyester forms a central component and has a hydrophilic group at the terminal and the branched terminal. The highly branched polyester oligomer containing a hydrophilic group at the terminal may further contain an ether group, and the hydrophilic group is a hydroxyl group, an alkoxy group, a carboxyl group or an alkoxycarbonyl group.

The highly branched polyester oligomer containing a hydrophilic group at the terminal may be represented by the following Chemical Formula 1, but is not limited thereto.

In the above formula

X is a branched polyester residue of 2 to 20 carbon atoms having 2 to 8 hydroxyl groups at the terminal constituting the dendrimer

B is a branched polyester moiety bound to the central component and having a hydroxyl group

n is 2 to 4, which means the number of generation of dendrimer

A is an alkyl group, a hydroxyl group, an alkoxy group, a carboxyl group or an alkoxycarbonyl group.

The hyperbranched polyester oligomer containing a hydrophilic group at the terminal is preferably 400 to 5,000 weight average molecular weight measured by gel permeation chromatography (GPC) using polystyrene as a standard material, more preferably 500 To 3,000. If the molecular weight is in the above-described range, there is an advantage of easy synthesis.

The hyperbranched polyester oligomers containing a hydrophilic group at the ends may be prepared and used directly or purchased. For example, pentaerythritol and dimethylol proponic acid can be obtained by reacting in the presence of a catalyst.

The hyperbranched polyester oligomer containing a hydrophilic group at the end is preferably included in an amount of 0.1 to 15 parts by weight based on 100 parts by weight of the alkali-soluble resin. If the content of the hyperbranched polyester oligomer containing a hydrophilic group at the end is less than 0.1 parts by weight, the property of improving developability is not expressed, and if it is included more than 15 parts by weight, the solubility is too large to prevent pattern formation.

In addition, the solvent may be used as long as it can dissolve the aforementioned components, has a suitable drying speed, and can form a uniform and smooth coating film after evaporation of the solvent.

In this case, the solvent may be a glycol ether ester including ethyl cellosolve acetate, methyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate; Recall ethers including ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether and propylene glycol monoethyl ether; Esters including ethyl acetate, butyl acetate, amyl acetate and ethyl pyruvate; Ketones including acetone, methyl isobutyl ketone, 2-heptone and cyclohexanone; And it is preferable that it is 1 type, or 2 or more types of mixtures chosen from the group which consists of cyclic ester containing (gamma) -butyrol acetone, More preferably, it is propylene glycol monomethyl ether or propylene glycol monomethyl ether acetate. It is preferable that a solvent is 50-200 weight part with respect to 100 weight part of alkali-soluble resin.

 At this time, when the solvent is less than the above range, the solubility is insufficient to dissolve the raw material, if the solvent exceeds the above range, the viscosity is too low to obtain the desired film thickness during coating.

The positive photoresist composition may further include one or two or more additives of colorants, dyes, plasticizers, adhesion promoters, speed promoters, dissolution inhibitors, or surfactants to cover the substrate to improve performance according to the characteristics of individual processes. Can be.

The positive photoresist composition of the present invention may be applied to a substrate in conventional manner, including dipping, spraying, spinning 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 according to the type and method of the spinning apparatus.

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

The coated positive photoresist composition may be soft baked at a temperature of 20 to 110 ° C. The soft bake is to evaporate the solvent without pyrolyzing the solid component in the photoresist composition. It is generally desirable to minimize the concentration of the solvent through a soft bake process, so this treatment is performed until most of the solvent has evaporated leaving a thin coating of photoresist composition on the substrate.

Next, the substrate on which the photoresist film is formed is exposed using a suitable mask or template. At the time of exposure, it is preferable to expose with a short wavelength high energy ray, X-ray, or an electron beam of wavelength 500nm or less.

The substrate including the exposed photoresist film is sufficiently immersed in an alkaline developing aqueous solution, and then left until all or almost all of the exposed photoresist film is dissolved. Although it does not specifically limit as said alkaline developing aqueous solution, The aqueous solution containing alkali hydroxide, ammonium hydroxide, tetramethylammonium hydroxide (TMAH), (2-hydroxyethyl) trimethyl ammonium hydroxide (also called "choline") Can be used.

After the exposed portion is dissolved and removed, the substrate on which the photoresist pattern is formed is taken out of the developer, and then a hard bake process may be performed to enhance adhesion and chemical resistance of the photoresist film. The hard bake process is preferably performed at a temperature below the softening point of the photoresist film, more preferably at a temperature of about 100 to 150 ℃.

Subsequently, the substrate on which the photoresist pattern is formed is etched using wet etching using an etching solution or dry etching using a gas plasma. At this time, the substrate located below the photoresist pattern is protected. After the substrate is treated in this manner, a fine circuit pattern is formed on the substrate by removing the photoresist pattern with an appropriate stripper.

Hereinafter, the present invention will be described in detail by way of examples.

However, the following examples are merely to illustrate the invention, but the content of the present invention is not limited by the following examples.

Synthesis Example 1 Synthesis of Hyperbranched Polyester Oligomer (C-1)

6.8 parts by weight of pentaerythritol (manufactured by Samyang), 80.4 parts by weight of azotropic cooling condenser, agitator and temperature controller, 80.4 parts of dimethylol proponic acid (manufactured by Nippon Kasei) 0.02 Parts by weight of dibutyl tin oxide (manufacturer: Akemis Co., Ltd., product name: FASCAT 4201) were added to the reactor, and the temperature was raised to 150 ° C. Esterification condensation dehydration starts to escape at 150 ℃, when the temperature of the azo tropic condenser drops below 50 ℃ to increase the temperature of the reactor by 10 ℃ by raising the reaction temperature to 210 ℃. When the condenser temperature no longer increased at the reaction temperature of 210 ° C., 20 parts by weight of toluene was charged. The ester reaction was induced as a forward reaction. And lowered the temperature to room temperature.

The hyperbranched polyester oligomer containing a hydrophilic group at the terminal synthesized by the above method had a weight average molecular weight of 2,850 measured by gel permeation chromatography (GPC) using polystyrene as a standard material.

Examples 1-4 and Comparative Example 1: Preparation of Positive Photoresist Composition

The resins, photosensitive compounds and hyperbranched polyester oligomers (dendritic oligomers) listed in Table 1 below are mixed according to the indicated amounts, and the components are stirred and dissolved at room temperature for 3 hours in a solvent shown in Table 1 After stirring, the mixture was stirred again at 60 ° C, cooled to room temperature, and filtered with a 0.1 µm filter to prepare a positive photoresist composition.

Suzy Photosensitizer Dendritic oligomers menstruum Kinds Parts by weight Kinds Parts by weight Kinds Parts by weight Kinds Parts by weight Example 1 a-1 / a-2 50/50 b-1 15 c-1 0.1 d-1 100 Example 2 a-1 / a-2 50/50 b-1 15 c-1 1.0 d-1 100 Example 3 a-1 / a-2 50/50 b-1 15 c-1 3.0 d-1 100 Example 4 a-1 / a-2 50/50 b-1 15 c-1 5.0 d-1 100 Comparative Example 1 a-1 / a-2 50/50 b-1 15 - - d-1 100

a-1: a novolak resin having a weight average molecular weight of 20,000 m / p cresol in terms of polystyrene

a-2: novolak resin having a weight average molecular weight of 20,000 m / p cresol in terms of polystyrene

b-1: ester compound of 2,3,4,4'-tetrahydroxybenzophenone and 1,2-naphthoquinone diazide-5-sulfonyl chloride

c-1: Hyperbranched polyester oligomer prepared in Synthesis Example 1

d-1: propylene glycol monomethyl ether acetate

Test Example: Evaluation of Photoresist Composition Properties

The positive photoresist compositions of Examples 1 to 4 and Comparative Example 1 were added dropwise onto a 4 inch bare glass, respectively, rotated at a constant rotational speed, and the glass was heated and dried at 110 ° C. for 90 seconds to form a 1.60 μm thick film. Formed. After mounting a mask having a predetermined shape on the film film, and irradiated with ultraviolet rays, and then immersed in a 2.38% by weight aqueous solution of tetramethylammonium hydroxide (TMAH) for 60 seconds to remove the portion exposed to ultraviolet rays to remove the photoresist pattern Formed.

end. Residual rate

After baking at 110 ° C., the film was developed in a 2.38% by weight aqueous solution for 60 seconds without exposure, and the film thicknesses before and after the development were compared.

Residual film ratio = (Thick film thickness / Pre-film thickness) X 100

In Table 2 below, when the residual film ratio is 97% or more, ◎, 94-96%, ○, 90-93% △, and less than 90% are indicated by X.

I. Developability

After the photoresist was coated on the molybdenum-deposited glass, the baking process was carried out, and the entire surface of the coated glass was irradiated with ultraviolet rays, and then immersed in a 23.degree. C. tetramethylammonium hydroxide (TMAH) 2.38 wt% aqueous solution for 1 minute. The glass is then washed with ultrapure water to compare the amount of resist remaining.

In the following Table 2, when the amount of resist remaining in the entire glass is less than 1%,?, 1 ~ 2%,?, 3-5%,?, And 5% are indicated as X.

All. Peelability

The photoresist was patterned on molybdenum-deposited glass, and then immersed in PRS-2000 (Dongwoo Finechem Co., Ltd.) stripping solution heated to 50 ° C for 1 minute, and then the glass was washed with ultrapure water to remove the remaining resist. Compare the quantities.

In the following Table 2, when the amount of resist remaining in the entire glass is less than 1%,?, 1 to 5%,?, 6 to 10%,?, And 10%, X is indicated.

Residual rate Developability Peelability Example 1 ◎ ◎ ○ Example 2 ◎ ◎ ◎ Example 3 ◎ ◎ ◎ Example 4 ◎ ◎ ◎ Comparative Example 1 ◎ △ X

From the results of Table 2, Examples 1 to 4 containing a branched (hyperbranched) polyester oligomer containing a hydrophilic group at the terminal of the present invention is excellent in residual film ratio, peelability, developability compared to Comparative Example 1 Able to know.

Claims (12)

A positive photoresist composition comprising an alkali-soluble resin, a photosensitizer, a hyperbranched polyester oligomer containing a hydrophilic group at the end, and a solvent. The method according to claim 1, based on 100 parts by weight of alkali-soluble resin
10 to 20 parts by weight of the photosensitizer;
0.1 to 15 parts by weight of a hyperbranched polyester oligomer containing a hydrophilic group at the end; And
A positive photoresist composition comprising 50 to 200 parts by weight of a solvent. The positive photoresist composition of claim 1, wherein the hyperbranched polyester oligomer containing a hydrophilic group at the terminal is a compound represented by the following Chemical Formula 1.
[Formula 1]
X- [B] nA
In the above formula
X is a branched polyester residue of 2 to 20 carbon atoms having 2 to 8 hydroxyl groups at the terminal constituting the dendrimer
B is a branched polyester moiety bound to the central component and having a hydroxyl group
n is 2 to 4, which means the number of generation of dendrimer
A is an alkyl group, a hydroxyl group, an alkoxy group, a carboxyl group or an alkoxycarbonyl group. The positive photoresist composition of claim 1, wherein the alkali-soluble resin is a novolak resin. The positive photoresist composition of claim 4, wherein the weight average molecular weight of the novolak resin is 2,000 to 50,000 in terms of polystyrene. The positive photoresist composition of claim 1, wherein the photosensitive agent is an ester compound of a phenolic compound having a hydroxy group and a quinonediazide sulfonic acid compound. The method of claim 6, wherein the phenolic compound having a hydroxy group is 2,3,4,4'-tetrahydroxy benzophenone, trihydroxy benzophenone 2,3,4-trihydroxybenzophenone, 2,3,4 , 4-tetrahydroxybenzophenone, 2,3,4,2,4-pentahydroxybenzophenone, tris 4-hydroxy phenylmethane, 1,3,5-tris 4-hydroxy a-dimethylbenzylbenzene, 1,1-bis-4-hydroxyphenyl-1-4-1-4- hydroxyphenyl 1-methylethyl phenyl ethane, 2- (3,4-dihydroxyphenyl) -2- (4-hydroxy Phenyl) propane, a positive photoresist composition, characterized in that one or a mixture of two or more selected from the group consisting of. The positive photoresist composition of claim 6, wherein the quinonediazide sulfonic acid compound is o-quinonediazide sulfonic acid. The method of claim 8, wherein the o-quinonediazide sulfonic acid is 1,2-naphthoquinonediazide-5-sulfonic acid, 1,2-naphthoquinonediazide-4-sulfonic acid, 1,2-benzoquinonediazide- A positive photoresist composition, characterized in that one or two or more mixtures selected from the group consisting of 4-sulfonic acid and derivatives thereof. The positive photoresist composition according to claim 1, wherein the weight average molecular weight of the hyperbranched polyester oligomer containing a hydrophilic group at the terminal is 400 to 5,000 in terms of polystyrene. The method of claim 1, wherein the solvent comprises: glycol ether esters including ethyl cellosolve acetate, methyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate;
Recall ethers including ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether and propylene glycol monoethyl ether;
Esters including ethyl acetate, butyl acetate, amyl acetate and ethyl pyruvate;
Ketones including acetone, methyl isobutyl ketone, 2-heptone and cyclohexanone; And
A positive photoresist composition, characterized in that it is one or a mixture of two or more selected from the group consisting of cyclic esters comprising γ-butyrolacetone. The positive photoresist composition of claim 1, wherein the positive photoresist composition further comprises one or two or more additives of a colorant, a dye, a plasticizer, an adhesion promoter, a rate enhancer, or a surfactant.