KR20100025158A

KR20100025158A - A chemical amplification type positive photoresist composition and a photoresist pattern forming method using the same

Info

Publication number: KR20100025158A
Application number: KR1020080083815A
Authority: KR
Inventors: 김성훈; 박순진
Original assignee: 동우 화인켐 주식회사
Priority date: 2008-08-27
Filing date: 2008-08-27
Publication date: 2010-03-09

Abstract

The present invention comprises (A) a resin comprising a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), the protection rate is 25 to 40%; (B) photoacid generator; And (C) relates to a chemically amplified positive photoresist composition comprising a quencher. The chemically amplified positive photoresist composition of the present invention has high resolution and a wide depth of focus when a halftone retardation shift mask is used at the time of forming a contact hole pattern. In addition, the chemically amplified positive photoresist composition of the present invention is characterized in that the side lobe is hardly generated when the pattern is formed, and the exposure margin is wide during underexposure.

Description

Chemically Amplified Positive Photoresist Composition and Resist Pattern Forming Method Using the Same {A CHEMICAL AMPLIFICATION TYPE POSITIVE PHOTORESIST COMPOSITION AND A PHOTORESIST PATTERN FORMING METHOD USING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemically amplified positive photoresist composition and a method of forming a photoresist pattern using the same, and in particular, by high energy radiation such as far ultraviolet rays (including excimer lasers), electron beams, X-rays, or radiant light. The present invention relates to a chemically amplified positive photoresist composition that is suitable for photolithography and the like, and to a photoresist pattern forming method using the same.

In recent years, as the degree of integration of integrated circuits has increased, submicron pattern formation has been required. In particular, photolithography using an excimer laser from fluoride krypton (KrF) or argon fluoride (ArF) has attracted attention in that it enables the production of 64M DRAM to 1G DRAM. As a resist suitable for a photolithography process using such an excimer laser, a so-called chemically amplified resist using an acid catalyst and a chemical amplification effect is adopted. In chemically amplified positive resists, in particular for positive resists for KrF excimer laser photolithography, poly (hydroxystyrene) resins in which some of their phenolic hydroxy groups are protected by groups dissociated by the action of an acid. The resin is often used in combination with a photoacid generator. When such a chemically amplified resist is used, the acid generated from the photoacid generator in the irradiation section of the radiation is diffused by subsequent heat treatment, and the solubility in the alkaline developer of the irradiation section is changed by the reaction using the generated acid as a catalyst. Or a negative pattern can be obtained.

In the past, a resist composition having a high contrast (γ value) has been used in order to increase the resolution and to obtain a good pattern shape. Technical development of such a resist composition has been carried out, and many publications have disclosed it. In particular, regarding the resin, which is a main part of the positive photoresist, many patent applications have been filed regarding the monomer composition, molecular weight distribution, synthesis method, and the like, and a certain result can be obtained. Regarding the photosensitive material which is another main component of the positive photoresist, a compound having many structures that are effective for high contrast is disclosed. By designing a positive photoresist using these techniques, it has become possible to develop an ultra-high resolution resist that can resolve a pattern having the same dimension as the wavelength of light.

On the other hand, nowadays, integrated circuits are increasing in degree of integration, and in the manufacture of semiconductor substrates such as ultra-LSIs, an ultrafine pattern composed of a line width of 0.3 µm or less is required. In addition, various experiments have been conducted to further increase the resolution by super resolution techniques such as exposure technique or mask technique. In the super resolution technology, various super resolution technologies have been studied on the light source surface, mask surface, hibernating surface, and sea surface, respectively. Further, on the light source surface, a technique has been studied to increase the resolution by forming a light source called a strain irradiation method, that is, a shape different from a conventional circular shape. In addition, a technique has been reported in which a phase shift mask is used to suppress phases, that is, to give a phase difference to light passing through a mask and to use the interference well, thereby obtaining a high resolution.

As an example of such a technique, the resist exposure method using the halftone system phase shift mask of Unexamined-Japanese-Patent No. 8-15851 attracts attention especially as a practical technique which improves the spatial image and contrast of a projection image. However, in the above exposure method, so-called sub-peaks (side lobe light) other than the main peak are generated in the intensity distribution of the exposure light reaching the resist. For this reason, in the above exposure method, a portion of the resist which is originally a non-exposed area is exposed. In particular, in the above exposure method, the sub peak becomes larger as the coherence degree σ is higher. When such a sub peak occurs at the time of exposure, unevenness caused by a sub peak occurs in the resist after exposure development in the positive resist, which is not preferable. In such a projection optical system of photolithography, various miniaturization studies have been conducted, and combinations of various super-resolution techniques have been continuously studied.

However, in the conventional positive photoresist, even when the super resolution technique is applied, the resolution is deteriorated. In addition, there have been reported cases of insufficient exposure margin, exposure latitude, unevenness (film loss), and deterioration of resist performance. For example, C.L.Lin reports that the modified illumination method degrades the density dependency of the pattern under the influence of the optical proximity effect. In addition, when forming a contact hole pattern using a halftone phase shift mask, it is pointed out that the periphery of the hole pattern is caused by the influence of side lobe light (SPIE, Vol. 2440, 61 (1995), SPIE, Vol. 2440, 278 (1995). In order to reduce the influence of side lobe light, studies have been made on surface treatment of positive resists with alkali after exposure, but there are problems such as complicated processes. In addition, even when these specific resist materials were used, the resistance to the sarlov light when forming the contact hole pattern using the halftone phase shift mask was insufficient. Therefore, there is a demand for a positive composition having excellent resolution and halftone retardation shift mask aptitude when forming a contact hole pattern.

In order to solve the problems of the prior art as described above, the object of the present invention is that various performances such as resolution and coating property are good, and in particular, when the halftone phase difference shift mask is used when forming a contact hole pattern, It is to provide a chemically amplified positive photoresist composition having a wide depth of focus. It is also an object of the present invention to provide a chemically amplified positive photoresist composition in which side lobes are hardly generated when a pattern is formed and the exposure margin at the time of underexposure is wide.

The present invention comprises (A) a resin comprising a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), the protection rate is 25 to 40%; (B) photoacid generator; And (C) provides a chemically amplified positive photoresist composition comprising a quencher.

In Chemical Formulas 1 and 2,

R ₁ and R ₂ are each independently hydrogen, a substituted or unsubstituted linear or branched alkyl group having 1 to 10 carbon atoms; A substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms; Or a substituted or unsubstituted heterocycloalkyl group having 3 to 10 carbon atoms,

R ₃ _and R ₄ are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 10 carbon atoms; A substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms; Or a substituted or unsubstituted linear or branched alkoxy group having 1 to 10 carbon atoms,

a1, a2, b and c are the molar ratios of each monomer Each independently a real number of 0 to 1,

0.25? [(B + c) / (a1 + a2 + b + c)] ≦ 0.4 or 0.01 ≦ [c / (a1 + a2 + b + c)] ≦ 0.2 in the mixture of the above resins (A).

The chemically amplified positive photoresist composition according to the present invention has a high resolution when a halftone phase shift mask is used in forming a contact hole pattern and has a wide depth of focus. In addition, the chemically amplified positive photoresist composition according to the present invention hardly generates side lobes when a pattern is formed, and has an effect of widening an exposure margin during underexposure.

The present invention provides a chemically amplified positive photoresist composition having a high resolution and a large depth of focus when a halftone phase shift mask is used in forming a contact hole pattern. In addition, the present invention provides a chemically amplified positive photoresist composition in which side lobes are hardly generated when a pattern is formed, and an exposure margin during underexposure is widened.

Hereinafter, the present invention will be described in detail.

The chemically amplified positive photoresist composition of the present invention contains (A) resin, (B) photoacid generator, and (C) quencher.

I. (A) resin

The resin (A) serves to form and maintain the pattern. The resin (A) is insoluble or poorly soluble in aqueous alkali, but becomes soluble in aqueous alkaline solution after dissociation of a functional group unstable with acid by the action of acid. The resin (A) includes a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), and a resin having a protection rate of 25 to 40%. Here, the structural units represented by Formula 1 and Formula 2 are preferably different structural units.

In Formulas 1 and 2, R ₁ , R ₂ are each independently hydrogen, a substituted or unsubstituted linear or branched alkyl group having 1 to 10 carbon atoms; A substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms; Or a substituted or unsubstituted heterocycloalkyl group having 3 to 10 carbon atoms, R ₃ _and R ₄ are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 10 carbon atoms; A substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms; Or a substituted or unsubstituted linear or branched alkoxy group having 1 to 10 carbon atoms, a1, a2, b, and c are each a molar ratio of each monomer. Each is independently a real number of 0 to 1.

R ₁ , R ₂ and R ₃ And R ₄ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms, or a cycloalkyl group having 3 to 10 carbon atoms. When the carbon number of the alkyl group satisfies the above-mentioned range, there is an advantage in that the solubility in the solvent is excellent and no residue is generated during the desorption reaction after exposure.

The protection ratio of the resin (A) is 25% to 40%. If the above range is satisfied, no side lobe is generated and an excellent pattern can be obtained. Here, a description will be given of a method for calculating the protection rate. For example, the protection rate is when a1 = 0.70 and b = 0.30 of the structural unit represented by the formula (1), and a2 = 0.80 and c = 0.2 of the structural unit represented by the formula (2). Is {b × (part by weight of the structural unit represented by Formula 1) + c × (part by weight of the structural unit represented by Formula 2)} / {(part by weight of the structural unit represented by Formula 1) + (Formula 2 Weight part of the structural unit represented by the following formula)} × 100.

In the mixture of resins (A), 0.25 ≦ [(b + c) / (a1 + a2 + b + c)] ≦ 0.4 or 0.01 ≦ [c / (a1 + a2 + b + c)] ≦ 0.2, There is an advantage in that the dissolution rate in the developer is excellent and the contrast is improved.

It is preferable that the dispersion degree of said (A) resin is 1.1-1.5. If the above range is satisfied, it may indicate that the resin having physical properties necessary for forming the pattern is precisely synthesized.

The structural unit represented by Chemical Formula 1 and the structural unit represented by Chemical Formula 2 are preferably included in the resin (A) in a weight ratio of 9: 1 to 5: 5. If the above range is satisfied, there is an advantage of maintaining an excellent pattern profile.

Part of the hydroxyl of the structural unit represented by the formula (1) and the structural unit represented by the formula (2) may be protected by a dissociable protecting group by the action of an acid.

The protecting group is not particularly limited, but may be one or two or more selected from a group in which quaternary carbon is bonded to an oxygen atom, an acetal-type group, and a non-aromatic cyclic compound. Examples of the group in which the quaternary carbon is bonded to an oxygen atom include t-butyl, t-butoxycarbonyl and t-butoxycarbonylmethyl. Examples of the acetal group include tetrahydro-2-pyranyl, tetrahydro-2-furyl, 1-ethoxyethyl, 1- (2-methylpropoxy) ethyl, 1- (2-methoxyethoxy) ethyl, 1- (2-acetoxyethoxy) ethyl, 1- [2- (1-adamantyloxy) ethyl] ethyl, 1- [2- (1-adamantanecarbonyloxy) ethoxy] ethyl, etc. Can be mentioned. Examples of such nonaromatic cyclic compounds include 3-oxocyclohexyl, 4-methyltetrahydro-2-pyron-4-yl (derived from mebaronic acid lactone), 2-methyl-2-adamantyl and 2-ethyl- 2-adamantyl etc. are mentioned. Among these, it is particularly preferable to include a 1-ethoxyethyl group having high stability against delay after exposure. The structural units represented by the above formulas (1) and (2) partially have a structure formed by protecting the hydroxy group of hydroxy styrene with 1-ethoxyethyl group, and have a structure formed by partially protecting the isopropyl group. .

The weight average molecular weights of the structural units represented by Formula 1 and the structural units represented by Formula 2 are preferably 9,000 to 14,000, respectively. When the above-mentioned range is satisfied, the pattern can be easily formed, an appropriate dissolution rate can be realized with respect to the developer, and the development of residue after development can be prevented.

II. (B) Photoacid generator

The photoacid generator (B) is a compound that generates an acid by the action of light or radiation. The photoacid generator (B) is a substance that generates an acid by irradiating a substance or a resist composition comprising such a substance with high energy radiation such as ultraviolet rays, far ultraviolet rays, electron beams, X-rays or radiated light. The acid generated from the photoacid generator (B) acts on the resin to dissociate the functional group unstable to the acid present in the resin (A).

The photoacid generator (B) is preferably included in an amount of 0.1 to 6 parts by weight (in terms of solids) based on 100 parts by weight of the (A) resin (in terms of solids). If the above-described range is satisfied, development defects do not occur and thus the resolution is excellent, and the shape of the pattern is excellent.

It is preferable that the said (B) photo-acid generator contains the compound represented by following formula (3).

In Formula 3, R ₅ and R ₆ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms unsubstituted or substituted with a hydroxy group, an amino group or an alkoxy group having 1 to 6 carbon atoms; A cycloalkyl group having 3 to 10 carbon atoms unsubstituted or substituted with a hydroxy group, an amino group or an alkoxy group having 1 to 6 carbon atoms; Or an aryl group having 6 to 11 carbon atoms unsubstituted or substituted with an alkyl group having 1 to 20 carbon atoms, alkoxy having 1 to 6 carbon atoms or a halogen atom. Preferably, R ₅ and R ₆ are each independently n-propyl group, n-butyl group, n-octyl group, toluyl group, cyclohexyl group, 2,4,6-trimethylphenyl group, 2,4,6- Triisopropylphenyl group, 4-dodecylphenyl group, 4-methoxyphenyl group, 2-naphthyl group or benzyl group. More preferably, in Formula 3, R ₅ and R ₆ are each independently n-propyl group, n-butyl group or cyclohexyl group.

The photoacid generator (B) is more preferably used by mixing the compound represented by the formula (3) and other photoacid generators having high acidity and high transmittance. The other photoacid generator can maintain a high resolution in a thick film because the transmittance is larger than the conventional photoacid generator.

The other photoacid generators include onium salt compounds, s-triazine-based organic halogen compounds, sulfone compounds, sulfonate compounds, and the like, and these may be used alone or in combination of two or more thereof. Specific examples of the other photoacid generators include diphenyl iodonium trifluoromethanesulfonate, 4-methoxyphenylphenyl iodonium hexafluoroantimonate, 4-methoxyphenylphenyl iodonium trifluoromethanesulfonate , Bis (4-t-butylphenyl) iodonium tetrafluoroborate, bis (4-t-butylphenyl) iodonium hexafluorophosphate, bis (4-t-butylphenyl) iodonium hexafluoroantimonate , Bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium trifluoromethanesulfonate, 4-methylphenyldiphenylsulfonium perfluorobutanesulfonate, 4-methylphenyldiphenylsulfonium perfluorooctanesulfonate, 4-methoxyphenyldiphenylsulfonium hexafluoroantimonate, 4-methoxyphenyldi Phenylsulfonium trifluorome Tansulfonate, p-tolyldiphenylsulfonium trifluoromethanesulfonate, 2,4,6-trimethylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-t-butylphenyldiphenylsulfonium trifluoro Methanesulfonate, 4-phenylthiophenyldiphenylsulfonium hexafluorophosphate, 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, 1- (2-naphtolylmethyl) thiolanium hexafluoroanti Monate, 1- (2-naphtolylmethyl) thiolanium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium hexafluoroantimonate, 4-hydroxy-1-naphthyl Dimethylsulfonium trifluoromethanesulfonate, N- (trifluoromethylsulfonyloxy) -5-norbornene-2,3-dicarboxyimide, N- (trifluoromethylsulfonyloxy) naphthali Mead etc. are mentioned. Among them, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, and triphenylsulfonium trifluoro which have a positive ion group of triphenylsulfonium, a fluorine group as an anion group, and a high acidity and high lipophilic property Romethanesulfonate, triphenylsulfonium 2,4,6-triisopropylbenzenesulfonate, 4-methylphenyldiphenylsulfonium perfluorobutanesulfonate, 4-methylphenyldiphenylsulfonium perfluorooctanesulfonate, 4-methoxyphenyldiphenylsulfonium hexafluoroantimonate, 4-methoxyphenyldiphenylsulfonium trifluoromethanesulfonate, p-tolyldiphenylsulfonium trifluoromethanesulfonate, 2,4, 6-trimethylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-t-butylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-phenylthiophenyldiphenylsulfonium hexafluorophosphate and 4- Phenylthiophenyldiphenylsulfonium hexafluoroantimonate is preferred.

When the (B) photoacid generator is used by mixing the compound represented by Chemical Formula 3 with the other photoacid generator, the mixing ratio (weight%) of the compound represented by Chemical Formula 3 with another photoacid generator is 50:50 to 90:10 is preferred. When included in the above range, the profile of the photoresist is excellent, there is an advantage that can prevent the development failure.

III. (C) Quencher

The (C) quencher prevents performance degradation caused by deactivation of the acid associated with release after exposure.

The (C) quencher is preferably 100 parts by weight of the (A) resin (in terms of solid content), and 0.001 to 10 parts by weight (in terms of solid content). When included in the above-described range, the acid is not diffused in a region other than the exposure region, so that the profile can be kept constant, which is excellent in sensitivity and suppresses development defects.

The (C) quencher is preferably a synthesized nitrogen-containing basic organic compound. Specific examples of the (C) quencher include tetramethylammonium hydroxide, tetra-n-butylammonium hydroxide, tetra-n-hexylammonium hydroxide, tetra-n-octylammonium hydroxide, phenyltrimethylammonium Hydroxide, 3- (trifluoromethyl) -phenyltrimethylammonium hydroxide, (2-hydroxyethyl) trimethylammonium hydroxide, dicyclohexylmethylamine, 2,6-diisopropylaniline, tris ( 2- (2-methoxyethoxy) ethyl) amine etc. are mentioned. In addition, a hindered amine compound having a piperidine backbone as described in JP-A-11-52575 can also be used as a quencher. In addition, dicyclohexylmethylamine, tetra-n-butylammonium hydroxide, tris (2- (2-methoxyethoxy) ethyl) amine may be used to form a good pattern under conditions of high film thickness and high sensitivity. It is preferable to use.

Ⅳ. (D) organic solvent

The chemically amplified positive photoresist composition of the present invention may further include (D) an organic solvent to provide the resist composition in solution. The organic solvent (D) dissolves the respective components, has a suitable drying rate, and provides a smooth film after evaporation of the organic solvent (D). In addition, the organic solvent (D) is not particularly limited, and may be a conventional organic solvent used in the technical field of the present invention.

The organic solvent (D) may include one or two selected from the group consisting of glycol ether esters, esters, ketones, cyclic esters and alcohols. Examples of the glycol ether esters include ethyl cellosolve acetate, methyl cellosolve acetate, propylene glycol monomethyl ether acetate, and the like. Examples of such esters include ethyl lactate, butyl acetate, amyl acetate, ethyl pyruvate and the like. Acetone, methyl isobutyl ketone, 2-heptanone, cyclohexanone, etc. are mentioned as said ketone. Examples of the cyclic esters include γ-butyrolactone and the like. In addition, examples of the alcohol include 3-methoxy-1-butanol.

The amount of the organic solvent (D) is not particularly limited as long as the chemically amplified positive photoresist of the present invention may exist in a solution state, but is preferably included in an amount of 400 to 700 parts by weight based on 100 parts by weight of the resin (A). Do. If included in the above range, each component is sufficiently dissolved, there is an advantage that can be uniformly mixed, there is an advantage that can maintain a smooth surface even if the solvent is dried during the photoresist patterning process.

In addition, the chemically amplified positive photoresist compositions of the present invention may include small amounts of various additives such as sensitizers, dissolution inhibitors, other resins, surfactants, stabilizers, dyes, and the like.

Using the chemically amplified positive photoresist composition according to the present invention, a photoresist pattern may be formed by the following method.

The chemically amplified positive photoresist composition according to the present invention is formed on the etching target layer of the substrate by spin coating to form a photoresist film. Soft baking may be performed to form the photoresist film into a solid resist. After the electron beam is injected into the photoresist film as an exposure source, a post exposure bake is performed on the exposed resist film as necessary to promote the protecting group removal reaction. The baked resist film is developed with an alkaline developer to form a photoresist pattern.

The alkaline developer used in the present invention is sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia water, ethylamine, n-propylamine, triethylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide And (2-hydroxyethyl) trimethylammonium hydroxide may be one or two or more selected from the group consisting of, among these, tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide ( Usually called choline).

Hereinafter, preferred embodiments of the present invention are provided to aid in understanding the present invention. However, the following specific examples are provided only for easier understanding of the present invention, and the contents of the present invention are not limited thereto.

Synthesis Example 1 : One- Ethoxyethyl group partially Etherified Poly (hydroxystyrene) phosphorus Synthesis of A-1

40 g of poly (p-hydroxystyrene) [weight average molecular weight; 11,000, degree of dispersion: 1.1] (333 mmol calculated using the molecular weight of the p-hydroxystyrene structural unit) and 47 mg (0.25 mmol) of p-toluenesulfonic acid monohydrate and 720 g of propylene glycol monomethyl Dissolved in ether acetate. These solutions have a temperature of 60? And distillation under reduced pressure under the condition of 10 Torr (1,333 Pa) or less, and azeotropic dehydration. The weight of the solution after distillation was 337 g. This solution was transferred to a 500 ml four neck flask purged with nitrogen, and thereto was added dropwise 13.3 g (184 mmol) of ethyl vinyl ether, and they were reacted at 25 ° C. for 5 hours. To the reaction solution was added 62.3 g of propylene glycol monomethyl ether acetate and 320 g of methyl isobutyl ketone, additionally 240 mL of ion exchanged water was added and the mixture was stirred. Subsequently, the mixture was allowed to stand and the organic layer portion was taken out. 240 mL of ion-exchanged water was added to the organic layer again, the mixture was stirred and washed, and then left to stand to allow the liquid to separate. After performing rinsing with ion-exchanged water and liquid separation again, the organic layer was taken out and distilled under reduced pressure to remove water and methyl isobutyl ketone by azeotropic distillation with propylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether. An acetate solution was obtained. A solution of poly (p-hydroxy styrene) partially etherified with the resulting 1-ethoxyethyl group was obtained and the polymer was analyzed by 1 H-NMR. 40% of the hydroxyl groups in poly (p-hydroxystyrene) were etherified with 1-ethoxyethyl groups. This polymer is referred to as A-1, A-1 is represented by the formula (1), and has a molecular weight of 12,500, a degree of dispersion of 1.45, a R ₁ : methyl group, a R ₂ : ethyl group, a1 = 0.60, b = 0.40.

Synthesis Example 2 : One- Ethoxyethyl group partially Etherified Poly (hydroxystyrene) phosphorus Synthesis of A-2 Resin

The reaction was carried out in the same manner as in Synthesis Example 1, except that the amount of ethyl vinyl ether was changed to 10 g (138 mmol) to obtain a solution of poly (hydroxystyrene) partially etherified with 1-ethoxyethyl group. Treatment and analysis were performed. 30% of the hydroxyl groups in the poly (hydroxystyrene) were etherified with 1-ethoxyethyl groups. This polymer is referred to as A-2, wherein A-2 is represented by Formula 1 and has a molecular weight of 12,300, a degree of dispersion of 1.45, a R ₁ : methyl group, a R ₂ : ethyl group, a1 = 0.70, and b = 0.30.

Synthesis Example 3 : Isopropyl group partially Etherified Poly (hydroxystyrene) phosphorus Synthesis of A-3 Resin

650 g of poly (p-hydroxystyrene) [＇VP-8000 ', manufactured by Nippon Soda KK, weight average molecular weight: 8000, dispersion degree: 1.2] (5.41 mol calculated using the molecular weight of p-hydroxystyrene structural unit) ) And 6.5 kg of acetone were added and stirred to dissolve them. Then, 246 g (2.43 mol) of triethylamine was added thereto, and the mixture was heated at 35 占 폚. 130.6 g of isopropyl chloride (1.62 mol, 0.30 equivalent based on the hydroxyl group of poly (p-hydroxystyrene)) was added dropwise into this resin solution over about 30 minutes. After the mixture was stirred at 35 ° C. for 3 hours, 6.5 kg of methyl isobutyl ketone were added and the mixture was washed three times with an aqueous 2% oxalic acid solution. The resulting organic layer was further washed with ion exchanged water to separate the liquid and this process was repeated five times. From this organic layer, the solvent was distilled off and concentrated until the resin solution content became 2.0 kg. 6.0 kg of propylene glycol monomethyl ether acetate were then added and the mixture was further concentrated to 2.5 kg to obtain a solution of poly (p-hydroxystyrene) partially esterified with isopropyl groups. The resulting polymer was analyzed by 13 C-NMR. 30% of the hydroxyl groups in the poly (hydroxystyrene) were esterified with isopropyl groups. This polymer is referred to as A-3, wherein A-3 is represented by Formula 2, having a molecular weight of 10,000, a dispersion of 1.4, and R ₃ R ₄ : methyl group, a2 = 0.70, c = 0.30.

Example 1 To 4 and Comparative Example 1 To 3: chemically amplified positive Photoresist Preparation of the composition

The components shown in Table 1 were mixed at the indicated composition ratios (in terms of solids), and filtered through a fluorine resin filter having a pore diameter of 0.2 μm to prepare a resist solution.

Resin (part by weight) Photoacid Generator (parts by weight) Quencher (parts by weight) Solvent (part by weight) Example 1 A-1 / A-2 / A-3 50 / 23.3 / 26.7 = 100 B-1 / B-2 3.7 / 0.74 = 4.44 C-1 / C-2 / C-3 0.0283 / 0.0283 / 0.156 = 0.2126 D-1 563 Protection rate: 35% Example 2 A-1 / A-2 / A-3 30 / 43.3 / 26.7 = 100 B-1 / B-2 3.7 / 0.74 = 4.44 C-1 / C-2 / C-3 0.0283 / 0.0283 / 0.156 = 0.2126 D-1 563 Protection rate: 33% Example 3 A-1 / A-2 / A-3 10 / 63.3 / 26.7 = 100 B-1 / B-2 3.7 / 0.74 = 4.44 C-1 / C-2 / C-3 0.0283 / 0.0283 / 0.156 = 0.2126 D-1 563 Protection rate: 31% Example 4 A-1 / A-2 / A-3 5 / 78.3 / 16.7 = 100 B-1 / B-2 3.7 / 0.74 = 4.44 C-1 / C-2 / C-3 0.0283 / 0.0283 / 0.156 = 0.2126 D-1 563 Protection rate: 28% Comparative Example 1 A-1 100 B-1 / B-2 3.7 / 0.74 = 4.44 C-1 / C-2 / C-3 0.0283 / 0.0283 / 0.156 = 0.2126 D-1 563 Protection rate: 40% Comparative Example 2 A-2 100 B-1 / B-2 3.7 / 0.74 = 4.44 C-1 / C-2 / C-3 0.0283 / 0.0283 / 0.156 = 0.2126 D-1 563 Protection rate: 30% Comparative Example 3 A-1 / A-2 50/50 = 100 B-1 / B-2 3.7 / 0.74 = 4.44 C-1 / C-2 / C-3 0.0283 / 0.0283 / 0.156 = 0.2126 D-1 563 Protection rate: 35%

A-1: Resin with a molecular weight of 12,500 containing 1-ethoxyethyl protecting group and a dispersity of 1.45 relative to the hydroxy group of hydroxystyrene, a1 = 0.60, b = 0.40

A-2: A1 = 0.70 and b = 0.30 with a resin having a molecular weight of 12,300 and a dispersity of 1.45 containing a 1-ethoxyethyl protecting group relative to the hydroxy group of hydroxystyrene.

A-3: Resin with a molecular weight of 10,000 containing an isopropyl protecting group and a dispersity of 1.4 with respect to the hydroxy group of hydroxystyrene, a2 = 0.70, c = 0.30

B-1: Diazodisulfone type photoacid generator in which R ₅ and R ₆ in Formula 3 are each cyclohexyl group

B-2: triphenylsulfonium 2,4,6-triisopropylbenzenesulfonate

C-1: dicyclohexylmethylamine

C-2: tris (2- (2-methoxyethoxy) ethyl) amine

C-3: tetra-n-butylammonium hydroxide

D-1: Propylene Glycol Monomethyl Ether Acetate

Test Example ; Chemically Amplified Positive Resist Evaluation of the properties of the composition

The resist solutions of Examples 1 to 4 and Comparative Examples 1 to 3 were applied onto a silicon wafer substrate treated with hexamethyldisilazane using a spin coater, and the thickness of the resist film after drying was 0.62 μm. The substrate on which the dried resist film was formed was subjected to preheat treatment for 60 seconds on a hot plate at 100 ° C. The wafer substrate having the resist film thus formed was gradually exposed to light using a scanning exposure apparatus ['NSR-S203B' manufactured by Nikon Corp., NA = 0.63, sigma = 0.43] having an exposure wavelength of 248 nm (KrF). Exposure was performed to form line and space patterns. Subsequently, in the hot plate, post-exposure heat treatment was performed at 110 ° C. for 60 seconds. In addition, paddle development was performed for 60 seconds using an aqueous 2.38% tetramethylammonium hydroxide solution. The pattern after development was observed with a scanning electron microscope, and the effective sensitivity, resolution and profile were examined by the method described below, and the test results are shown in Table 2 below.

※ Effective Sensitivity: This is described as the exposure amount when the 0.215 탆 hole pattern is 1: 1.

Resolution: This is described as the minimum size of the hole pattern separated by the exposure dose at the effective sensitivity.

※ Underexposure margin during hole pattern formation: Set the exposure dose that reproduces the 0.215 µm contact hole pattern of the mask as the optimal exposure dose (E1), and set the exposure dose that satisfies the target size of 215 µm-10% when the exposure dose is reduced to E2. (E1-E2) * 100 / E2 (%) was made into underexposure margin. The larger this value, the better the exposure margin, and the smaller the value, the lower the value.

profile Sensitivity (mJ / ㎠) Resolution (μm) Sidelobe Generation Exposure margin (%) when underexposure is formed Example 1 ◎ 46 0.175 × 11 Example 2 ○ 47 0.175 × 10 Example 3 ○ 45 0.18 × 8 Example 4 ○ 48 0.18 × 7 Comparative Example 1 × 45 0.2 ○ 4 Comparative Example 2 × 46 0.2 ○ 4 Comparative Example 3 × 46 0.2 ○ 5

Profile: ◎: Very good, ○: Excellent, ×: Poor (unevenness)

Sidelobe generation: ○: Sidelobe generation, ×: Sidelobe generation

As shown in Table 2, it can be seen that the resist composition of Examples 1 to 4 according to the present invention is excellent in profile and resolution when compared to the resist compositions of Comparative Examples 1 to 3. In addition, Examples 1 to 4 can be seen that the side lobe does not occur, so the profile is good and the hole pattern peripheral portion is not uneven. In addition, it can be seen that the resist compositions of Examples 1 to 4 have better exposure margins under underexposure than the resist compositions of Comparative Examples 1 to 3.

Through this, it can be seen that when forming the contact hole pattern, the resist of the present invention having a certain range of protecting groups of the formulas (1) and (2) is effective in showing a good profile.

FIG. 1 is a photograph of a pattern formed using the resist composition of Example 1 and taken of a profile using a Hitachi scanning electron microscope, and FIG. 2 is a pattern formed of the resist composition of Example 2, followed by a Hitachi scanning electron microscope. A picture taken using a profile.

1 and 2, it can be seen that the resist composition pattern of Example 1 is excellent in profile because the side lobe does not occur, but the resist composition pattern of Comparative Example 1 is not excellent in profile because the side lobe occurs. have.

FIG. 1 is a photograph of a pattern formed of a resist composition of Example 1 and taken of a profile using a Hitachi scanning electron microscope. FIG.

FIG. 2 is a photograph of a pattern formed of the resist composition of Comparative Example 1 and taken of a profile using a Hitachi scanning electron microscope. FIG.

Claims

(A) a resin containing a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2) and having a protection rate of 25 to 40%;

(B) photoacid generator; And

(C) a chemically amplified positive photoresist composition comprising a quencher:

In Chemical Formulas 1 and 2,

The method according to claim 1,

Based on 100 parts by weight of the (A) resin,

0.1 to 6 parts by weight of the photoacid generator (B); And

The chemically amplified positive photoresist composition comprising (C) 0.001 to 10 parts by weight of the quencher.

The method according to claim 1,

Dispersion degree of the resin (A) is 1.1 to 1.5, the chemically amplified positive photoresist composition.

The method according to claim 1,

The structural unit represented by the formula (1) and the structural unit represented by the formula (2) is a chemically amplified positive photoresist composition, characterized in that included in the (A) resin in a weight ratio of 9: 1 to 5: 5.

The method according to claim 1,

Part of the hydroxyl group of the structural unit represented by the formula (1) and the structural unit represented by the formula (2) are each protected with a protecting group capable of dissociation by acid, chemically amplified positive photoresist composition.

The method according to claim 5,

The protecting group is a chemically amplified positive photoresist composition, characterized in that the quaternary carbon is one or two or more selected from a group bonded to an oxygen atom, an acetal-type group and a non-aromatic cyclic compound.

The method according to claim 1,

Chemical amplification-type positive photoresist composition, characterized in that the weight average molecular weight of the structural unit represented by the formula (1) and the structural unit represented by the formula (2) is 9,000 to 14,000, respectively.

The method according to claim 1,

(B) the photo-acid generator is a chemically amplified positive photoresist composition comprising a compound represented by the following formula (3):

In Chemical Formula 3,

R ₅ and R ₆ are each independently a hydroxy group, an amino group or a C 1-10 straight or branched chain alkyl group unsubstituted or substituted with an alkoxy group having 1 to 6 carbon atoms; A cycloalkyl group having 3 to 10 carbon atoms unsubstituted or substituted with a hydroxy group, an amino group or an alkoxy group having 1 to 6 carbon atoms; Or an aryl group having 6 to 11 carbon atoms unsubstituted or substituted with an alkyl group having 1 to 20 carbon atoms, alkoxy having 1 to 6 carbon atoms or a halogen atom.

The method according to claim 8,

R ₅ and R _{6 in} Chemical Formula 3 are each independently n-propyl group, n-butyl group, n-octyl group, toluyl group, cyclohexyl group, 2,4,6-trimethylphenyl group, 2,4,6- A chemically amplified positive photoresist composition selected from the group consisting of triisopropylphenyl group, 4-dodecylphenyl group, 4-methoxyphenyl group, 2-naphthyl group and benzyl group.

The method according to claim 8,

(B) the photoacid generator is a chemical amplification type, characterized in that it further comprises one or two or more selected from the group consisting of onium salt compound, s-triazine-based organic halogen compound, sulfone compound, and sulfonate compound Positive photoresist composition.

The method according to claim 1,

The chemically amplified positive photoresist composition further comprises (D) an organic solvent.