TW201433577A - Novel monomer, polymer and resist composition comprising the same - Google Patents

Abstract

The present invention provides a resist polymer as a homopolymer of adamantyl (meth)acrylate including hydroxyl groups, wherein the hydroxyl groups in the homopolymer are partially or entirely substituted with acetyl groups and a resist composition comprising the resist polymer. Therefore, the resist polymer prevents the decrease in thickness and thus deterioration in etching resistance of a resist in pattern formation using lithography and, particularly, in pattern formation by a NPD process, so that the resist polymer is useful for the formation of a micro resist pattern having excellent sensitivity and resolution and is also excellent in a contrast improvement effect.

Description

Resist polymer and resist composition containing the same

The present invention relates to a polymer for a resist which is useful for forming a pattern by photolithography, and a resist composition containing the polymer.

Recently, lithography technology is actively pursuing high-volume manufacturing (HVM, high volumn manufacturing) using ArF immersion lithography, and mainly develops technologies for achieving line widths of 50 nm or less. In particular, as a method for realizing a contact hole pattern of a line width of 30 nm, research on NTD (negative-tone development) is being actively conducted.

NTD (negative-tone development) is an image inversion technique that prints a critical dark field layer and obtains excellent image quality through a bright fileld mask. NTD resists typically utilize a resin containing an acid-labile group and a photoacid generator. When the NTD resist is exposed to actinic radiation, the photoacid generator forms an acid which blocks the acid labile group during post-exposure bake, thus causing polarity switching of the exposed regions. As a result, there is a difference in solubility between the exposed region and the unexposed region of the resist, and the unexposed region of the resist is eliminated by a specific organic developer such as a ketone, ester or ether organic developer, and therefore, A pattern generated by insoluble exposure areas.

Due to this specific mechanism of action, conventional 193 nm photoresist is suitable for In the case of NTD resists, specific problems can arise. As an example, the developed photoresist pattern has a large thickness loss compared to the pre-exposure resist layer, and thus, at the time of subsequent etching, a part of the resist pattern is completely etched, resulting in a pattern. defect. The thickness loss as described above is caused by the loss of the conventionally used large-volume acid-labile group, such as a large-sized tertiary ester group, which is cut off from the resist layer. For polarity switching, in the case of conventional 193 nm photoresists which require only a large volume of acid labile groups, the thickness loss is more severe due to the high content of the above groups. In order to solve the above problem, if a thicker resist layer is used, other problems such as pattern cracking and focus reduction may occur, and thus it is not a practical solution. In addition, pattern cracking occurs when NTD uses a typical 193 nm photoresist, due to the specific acid labile group from the base polymer of (meth) acrylate, especially involved in polarity conversion alone, For example, after cutting off the tertiary alkyl ester and the acetal leaving group, a relatively large amount of (meth)acrylic acid units produced by the exposed regions of the photoresist cause problems to be worsened. Further, in the case where such a conventional photoresist which is solely dependent on the above-mentioned highly polar acid-labile group is used for the NTD for polarity switching, there is another problem that the etching resistance is lowered.

Therefore, research on solving the above problems is being actively carried out.

Prior art literature.

Patent literature.

Patent Document 1: Korean Patent Laid-Open No. 2012-0026991 (published 2012.03.20).

Patent Document 2: Korean Patent Laid-Open No. 2012-0061757 (published on Jun. 2012.06.13).

Patent Document 3: Korean Patent Laid-Open No. 2012-0078672 (published on Jun. 2012.07.10).

Patent Document 4: Korean Patent Laid-Open No. 2012-0098540 (published on 2012.09. 05).

Patent Document 5: Korean Patent Laid-Open No. 2012-0101618 (published on 2012. 09.14).

Patent Document 6: Korean Patent Laid-Open No. 2012-0114168 (published on Jun. 2012.16).

An object of the present invention is to provide a polymer for a resist which is excellent in formation of a pattern by a photolithography technique, particularly when a pattern is formed by an NPD method, and has a reduced thickness and a low etching resistance of a resist. It is useful for a resist pattern of sensitivity, resolution, and contrast.

Another object of the present invention is to provide a resist composition containing the above polymer.

In order to achieve the above object, according to an embodiment of the present invention, there is provided a resist polymer which is a homopolymer of a hydroxyl group-containing adamantyl (meth) acrylate, and a hydroxyl group part or all of the above homopolymer Replaced by an acetal group.

It is preferable that the above-mentioned resist polymer has a structure of the following Chemical Formula 1:

In the above Chemical Formula 1, R is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; X _a and X _b are each independently an adamantane-diyl group; and R ₁ to R ₃ are each independently selected from a hydrogen atom and carbon. a group consisting of an alkyl group having 1 to 20 atoms, a cycloalkyl group having 3 to 30 carbon atoms, and a combination thereof, or an adjacent functional group is bonded to form a carbon atom having 3 to 30 carbon atoms. a cycloalkyl group, or an oxygen group bonded to R ₂ , forms a heterocycloalkyl group having 2 to 30 carbon atoms; a and b satisfy a+b=1, 0 a/(a+b)<1 and 0<b/(a+b) 1.

More preferably, the above-mentioned resist polymer may be selected from the group consisting of the compounds of the following Chemical Formulas 1a to 1e:

In the above chemical formulae 1a to 1e, a and b satisfy the condition of a + b = 1, 0 a/(a+b)<1 and 0<b/(a+b) 1.

Preferably, the resist polymer has a weight average molecular weight (hereinafter referred to as "Mw") in terms of gel permeation chromatography (GPC) polystyrene. 1,000~100,000g/mol.

Preferably, the molecular weight distribution of the above-mentioned resist polymer, that is, the ratio of the weight average molecular weight to the number average molecular weight (Mw/Mn) is 1 to 3.

According to another embodiment of the present invention, a resist composition containing the above polymer for a resist is provided.

The above resist composition is a reversal type resist composition for development.

Preferably, the content of the above-mentioned resist polymer is from 3 to 20% by weight based on the total weight of the resist composition.

According to another embodiment of the present invention, there is provided a method of forming a resist pattern, comprising: a step of coating the above resist composition on a substrate to form a resist film; and heat treating the resist film Thereafter, the step of exposing to a predetermined pattern; and the step of developing the exposed resist pattern.

Preferably, the above exposure process can be carried out using a light source selected from the group consisting of KrF excimer laser, ArF excimer laser, extreme ultraviolet laser, X-ray, and electron beam.

Preferably, the above development can be carried out using a reverse type organic developing solution.

Other specific matters of specific embodiments of the present invention are included in the detailed description below.

The polymer according to the present invention is a homopolymer, and there is no risk of the monomer being blocked, and an acetal group is introduced at the end thereof. Therefore, when a pattern is formed by photolithography, in particular, when a pattern is formed by the NPD method, it can be prevented. The thickness loss, while preventing the etch resistance of the resist due to the thickness loss, is useful to form a fine resist pattern having excellent sensitivity and resolution, and is excellent Different contrast improvement effects.

Fig. 1 is a graph showing the results of thickness loss according to energy change observed in the case of forming a resist film using the polymer of the present invention in Test Example 2.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited thereto, and the scope of the present invention should be determined by the scope of the claims.

Unless otherwise stated in the specification, all compounds or substituents may be substituted or unsubstituted. Here, substituted means that hydrogen is selected from a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an amino group, a decyl group, a methyl fluorenyl group, an alkoxy group, a nitrile group, an aldehyde group, an epoxy group, an ether group, an ester. , ester, carbonyl, acetal, keto, alkyl, perfluoroalkyl, cycloalkyl, heterocycloalkyl, allyl, benzyl, aryl, heteroaryl and derivatives thereof And any one of the groups consisting of their combinations is substituted.

Further, unless otherwise stated in the specification, a combination thereof means that two or more substituents are condensed and bonded by a single bond or a linker group or two or more substituents.

The hydroxyadamantyl (meth) acrylate monomer is a monomer which is often used in the preparation of a photoresist polymer for ArF, and has a larger number of carbon atoms than the number of oxygen atoms, so that etching resistance is improved. It also contains a hydroxyl group and therefore has good adhesion to the wafer. Further, in the resist, when the acid generated by the light irradiation is diffused, the proton transfer of the acid is smoother than the polymer for the resist composed of only carbon atoms and hydrogen atoms, thereby facilitating the acid. De-radical reaction of acid labile groups in the polymer.

In the present invention, a monomer for preparing a polymer for a resist is prepared by homopolymerization using only hydroxy adamantyl (meth) acrylate having the above characteristics. After the homopolymer, it reacts with an ether compound containing a reactive functional group such as vinyl ether to replace the hydroxy group with an acetal group having a relatively small size and a greater sensitivity to the developer, thereby forming a fine In the case of a pattern, particularly when a fine pattern is formed by the NTD method, the thickness of the resist film is prevented from being lost, and the contrast on the critical surface of the exposed region and the unexposed region is improved.

That is, the polymer for a resist according to an embodiment of the present invention is a homopolymer of adamantyl (meth) acrylate having a hydroxyl group, and a part or all of a hydroxyl group in the homopolymer is substituted with an acetal group.

Preferably, the above-mentioned resist polymer has a structure of the following Chemical Formula 1.

In the above Chemical Formula 1, R is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom or a methyl group, and X _a and X _b are each independently an adamantane-diyl group, and R ₁ to R ₃ may be used. Each of them is independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, and a combination thereof, or an adjacent functional group is combined to form a cycloalkyl group having 3 to 30 carbon atoms or a heterocyclic alkyl group having 2 to 30 carbon atoms together with an oxygen to which R _{2 is} bonded, preferably, the above R ₁ to R ₃ may be independently selected from hydrogen An atom, an alkyl group having 1 to 10 carbon atoms, a monocyclic cycloalkyl group having 3 to 14 carbon atoms, a bicyclic cycloalkyl group having 8 to 18 carbon atoms, and a carbon number of 10 to 30. a tricyclic cycloalkyl group, a tetracyclic cycloalkyl group having 10 to 30 carbon atoms, and a combination thereof, or R ₁ and R ₂ or R ₂ and R ₃ combined with R ₂ The linked oxygen together form a heterocycloalkyl group having 2 to 7 carbon atoms, more preferably selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, a t-butyl group and a cyclohexyl group. Group, or, R ₁ and R ₂ or R ₂ and R ₃ combine together to form an oxygen attached to R ₂ tetrahydropyranyl.

Further, in the above Chemical Formula 1, a and b represent the content of each repeating unit in the main chain, and also indicate the substitution ratio of the polymer dissolved in the developing solution.

According to the polymer of the present invention, the above a and b satisfy the content of a+b=1, and the content satisfies 0. a/(a+b)<1 and 0<b/(a+b) 1, its content preferably satisfies 0 a/(a+b) 0.5 and 0.5 b/(a+b) 1. Since the above repeating unit is contained in the above ratio, a finer pattern can be obtained, and the content of the repeating unit b having a hydroxyl group substituted by an acetal group is preferably 50 to 100% by mole, so that a uniform pattern can be formed on the entire wafer. Can reduce the occurrence of defects.

More preferably, the above polymer may be selected from the group consisting of the compounds of the following Chemical Formulas 1a to 1e, and the order of the respective repeating units in the structural formula may be changed.

In the above formula, a and b are as defined above.

The polymer for resist according to the present invention having the above structure can be obtained by the following steps: a step of preparing a homopolymer of a hydroxyl group-containing adamantyl (meth) acrylate (step 1), and the above polymer The step of reacting a hydroxyl group having a reactive functional group with an ether compound having a reactive functional group to substitute a hydroxyl group in the above polymer into an acetal group.

Specifically, first, a hydroxyl group-containing adamantyl (meth) acrylate is homopolymerized to prepare a hydroxyl group-containing adamantyl (meth) acrylate homopolymer (step 1).

The above-mentioned hydroxyl group-containing adamantyl (meth) acrylate can be produced by a conventional method, or a commercially available product can be used, specifically, as the above-mentioned hydroxyl group-containing adamantyl group (A) As the acrylate, 3-hydroxyadamantan-1-yl methacrylate (HAMA) represented by the following Chemical Formula 2a or 3-hydroxyl group represented by the following Chemical Formula 2b can be used. Adamantyl-1-yl acrylate compound, but is not limited thereto.

The homopolymerization of the above-mentioned hydroxyl group-containing adamantyl (meth) acrylate can be obtained by a polymerization method such as bulk polymerization, solution polymerization, suspension polymerization, bulk suspension polymerization, emulsion polymerization or the like by a conventional polymerization method, preferably through Free radical polymerization is obtained. In this case, as the radical polymerization initiator, for example, azobisisobutyronitrile (AIBN), benzammonium peroxide (BPO), laurel peroxide, azobisisohexylamine nitrile, azobis A conventional radical polymerization initiator such as valeronitrile or t-butyl hydroperoxide is not particularly limited.

Further, the above polymerization is an ether such as tetrahydrofuran, 1,4-dioxane or diisopropyl ether; a ketone such as methyl ethyl ketone or methyl isobutyl ketone; an ester such as ethyl acetate; It is carried out in a solvent such as an amine such as carbamide or dimethylacetamide.

Further, the molecular weight distribution of the prepared polymer can be appropriately adjusted by changing the amount of the polymerization initiator used and the reaction time, and after the termination of the polymerization, the unreacted monomers and by-products remaining in the reactant are preferably passed through a solvent. The precipitation method is removed.

Next, the homopolymer of the hydroxy-containing adamantyl (meth) acrylate prepared in the above step 1 is reacted with an ether compound containing a reactive functional group to form a hydroxyl group in the above homopolymer. The base is substituted with an acetal group (step 2).

The ether functional compound containing a reactive functional group may be a linear or cyclic ether compound containing an alkenyl group as an intramolecular reactive functional group, preferably an alkyl group having 1 to 5 carbon atoms (having 1 to 1 carbon atom) An alkenyl ether of 5 or a cyclic ether compound having an oxygen atom and a double bond in the ring. Specifically, one or more compounds selected from the group consisting of the following Chemical Formulas 3a to 3e can be used.

The above substitution reaction can be carried out in the presence of a compound such as trifluoroacetic acid or trifluoromethylacetic acid. In this case, these compounds can be used in a catalyst amount.

The polymer of the present invention prepared by the above preparation method uses only a hydroxyl group-containing adamantyl (meth) acrylate to prepare a homopolymer by homopolymerization, and thus is copolymerized with a conventional copolymer (co-polymer). The ter-polymer or tetra-polymer form resist can prevent the monomer from being blocked during the polymerization, and can improve the homogeneity of the resist composition. , thereby improving the line edge roughness.

Further, a homopolymer of adamantyl (meth) acrylate containing a hydroxyl group is prepared to make the polymer in a developing solution such as n-butyl acetate (n-butyl acetate, n-) as an NTD photoresist. The solubility in an organic solvent such as BA) is extremely lowered. Thereafter, a part or all of the hydroxyl group contained in the above homopolymer is replaced with an acetal group, so that the solubility in the organic developer is increased to an appropriate range, and at the same time, exposure is performed. In the region, the de-radical reaction of the above acetal group is initiated by acid, which can be reduced in organic Solubility in the developer. At this time, the above effect is enhanced by adjusting the substitution ratio of the acetal group to an appropriate range.

Further, introduction of an acetal group on the hydroxyl group minimizes the size of the leaving group which is removed by dissolution during development after the de-radical reaction, thereby reducing the thickness loss of the resist film, and further, the above acetal group is relative to Any other tertiary ester group or acid-sensitive group is sensitive, and therefore, it is immediately de-based, so that the contrast ratio of the interface between the exposed region and the unexposed region can be improved.

Further, in order to improve the formation of a resist pattern, a conventional resist polymer is polymerized by using a monomer having an acid-labile group to enhance adhesion to a wafer. The monomer, the monomer having the property of enhancing the etching resistance, and the like, but the polymer of the present invention uses only one monomer to obtain the above characteristics.

The following Reaction Formula 1 schematically shows a reaction mechanism in which a polymer of the present invention forms a pattern in an NTD photoresist. The following Reaction Formula 1 is only an example for explaining the present invention, and the present invention is not limited thereto.

In the above Reaction Scheme 1, a and b are the same as defined above, and c is an integer of 1.

When the resist pattern is formed by using the polymer (i) according to the present invention, a part of the hydroxyl group of the polymer (i) in the unexposed region is replaced with an acetal group, whereby an organic developer such as n-butyl acetate is introduced. In the case of development, as shown in the above Reaction Formula 1, the polymer (i) according to the present invention is dehydrated by an acid formed during exposure, and is converted into the above. In the form of the polymer (ii), the solubility in n-butyl acetate is extremely lowered, and it is insoluble, so that it is left as a pattern during development. Although the reaction mechanism as described above has been described for use in the ArF resist, it is not limited thereto, and it can be used in all lithography techniques of the CAR type such as KrF, EUV, and X-ray. Further, as described above, the case where it is used as an NTD pattern material has been described, but the resist polymer of the present invention is also applicable as a PTD pattern material.

The polymer according to the present invention may have a weight average molecular weight (hereinafter referred to as "Mw") in terms of polystyrene according to gel permeation chromatography (GPC, gel permeation chromatography) of 1,000 to 100,000 g/mol. When the weight average molecular weight of the above polymer is too small, the etching resistance may be insufficient. When the weight average molecular weight of the above polymer is too large, it may be difficult to form a suitable film or to reduce the enthalpy solubility. Preferably, the weight average molecular weight is 2,000 to 10,000. When g/mol, it showed excellent solubility with respect to a developing solution.

Further, it is preferred that the ratio of the weight average molecular weight to the number average molecular weight (Mw/Mn) of the above polymer has a molecular weight distribution of from 1 to 3, more preferably from 1 to 2. Further, if the molecular weight distribution of the above polymer exceeds 3, the line edge roughness may be poor. Therefore, when the resist additive belonging to the above-described weight average molecular weight and molecular weight distribution range is used as the photoresist composition, the corresponding physical properties can be exhibited in terms of developability, coatability and heat resistance.

According to another embodiment of the present invention, a resist composition containing the above polymer is provided.

Specifically, the above resist composition contains the above polymer and a solvent as a base polymer for a resist.

The above polymer may be as described above with respect to the total weight of the above resist composition Containing 3 to 20% by weight of the above polymer. If the content of the above polymer is less than 3% by weight, the viscosity of the composition is too low, so that it is difficult to form a film of a desired thickness, and pattern loss is severe due to a relatively large amount of photoacid generator. At 20% by weight, the film thickness is too thick to reduce the radiation penetration force, and it is difficult to obtain a longitudinal pattern.

Further, the above polymer may be contained together with a base polymer which is used as a base resin when a resist film is usually formed. As a specific example, a catalyst selected from the group consisting of (meth) acrylate polymer, (α-trifluoromethyl) acrylate-maleic anhydride copolymer, cycloolefin-maleic anhydride copolymer, polynorbornene, and through ring can be used. a polymer compound obtained by a ring-opening metathesis reaction of an olefin, a polymer compound obtained by adding hydrogen to a polymer obtained by a ring-opening metathesis reaction of a cycloolefin, and a hydroxystyrene and a (meth) acrylate derivative a polymer compound copolymerized with any one of styrene, vinyl naphthalene, vinyl anthracene, vinyl anthracene, hydroxyvinyl naphthalene, hydroxyvinyl anthracene, anthracene, hydroxy anthracene, decene, norbornadiene, A group consisting of a novolak resin and a mixture thereof.

In order to obtain a uniform smooth resist coating film, it is preferred to dissolve the above polymer and an acid generator in a solvent having a suitable volatilization speed and viscosity. Examples of the solvent which can be used in the present invention include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, methyl cellulose cellosolve, ethyl cellulose cellosolve, and propylene glycol monomethyl. Esters such as ethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methyl isopropyl ketone, cyclohexanone, ethyl methyl 2-hydroxypropionate, B A ketone such as ethyl 2-hydroxypropionate, 2-heptanone, ethyl lactate or γ-butyrolactone may be used alone or in combination of two or more.

The solvent can be appropriately adjusted in accordance with the physical properties of the solvent, that is, the volatility, the viscosity, and the like, so that a uniform resist film can be formed.

Further, the above resist composition may further contain an acid generator.

The acid generator is a photoacid generator (hereinafter referred to as "PAG"), and iodonium salts, sulfonium salts, sulfonium salts, diazonium salts, and the like may be used. One or more of the sulfonium salts represented by the following Chemical Formulas 4 and 5 can be preferably used as the pyridinium salt or the quinone imine, and the perfluorobutanesulfonic acid triphenylsulfonium salt is more preferably used.

In the above Chemical Formulas 4 and 5, X ₁ , X ₂ , Y ₁ and Y ₂ are each independently selected from a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an allyl group, and a perfluoro group having 1 to 10 carbon atoms. Any one of the group consisting of an alkyl group, a benzyl group, an aryl group having 6 to 30 carbon atoms, and a combination thereof, and the above X ₁ and X ₂ and Y ₁ and Y ₂ may be bonded to each other to form a carbon number of 3 To a saturated or unsaturated hydrocarbon ring of 30, X ₃ , X ₄ , X ₅ , Y ₃ , Y ₄ and Y ₅ are each independently selected from a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a halogen group, and a carbon atom. Alkoxy groups of 1 to 30, aryl groups having 6 to 30 carbon atoms, thiophenoxy, thioalkoxy having 1 to 30 carbon atoms, and 1 to 20 carbon atoms Any one of the group consisting of alkoxycarbonylmethoxy and combinations thereof, and the Z of the anion moiety is OSO ₂ CF ₃ , OSO ₂ C ₄ F ₉ , OSO ₂ C ₈ F ₁₇ , N (CF ₃ ) ₂ , N(C ₂ F ₅ ) ₂ , N(C ₄ F ₉ ) ₂ , C(CF ₃ ) ₃ , C(C ₂ F ₅ ) ₃ , C(C ₄ F ₉ ) ₃ or A functional group represented by the following Chemical Formula 6.

In the above Chemical Formula 6, V ₁ and V ₂ are each independently a halogen atom, W ₁ is -(C=O)- or -(SO ₂ )-, and W ₂ is an alkylene group W _{3 having} 1 to 10 carbon atoms. It is selected from a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, an aralkyl group having 7 to 30 carbon atoms, an aryloxy group having 6 to 30 carbon atoms, and 6 carbon atoms. Any one of the group consisting of an arylthio group of 30 and a heterocyclic group of 5 to 30 carbon atoms, and W ₄ is selected from the group consisting of a hydrogen atom, a halogen group, an alkyl group having 1 to 10 carbon atoms, and carbon. An alkoxy group having 1 to 10 atoms, a halogenated alkyl group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 30 carbon atoms, and a combination thereof Any of the groups, o is an integer from 0 to 1, and p is an integer from 0 to 2. When the anion in the acid generator contains a cyclic alkyl group, the diffusion length of the acid in the resist film can be appropriately kept short, and high permeability can be exhibited. As a result, a high-resolution resist can be obtained.

Preferably, the above anionic moiety Z may be selected from the group consisting of functional groups represented by the following Chemical Formulas 7-1 to 7-36.

Further, in the above Chemical Formulas 4 and 5, preferred examples of the cationic moiety include the structures represented by the following Chemical Formulas 8-1 to 8-16.

The acid generators as described above may be used singly or in combination of two or more. Further, the above acid generator may be contained in an amount of from 0.3 to 15 parts by weight, preferably from 0.5 to 10 parts by weight, more preferably from 2 to 10 parts by weight, based on 100 parts by weight of the polymer solid content. When the content of the acid generator exceeds 15 parts by weight, the perpendicularity of the pattern is remarkably lowered, and when it is less than 0.3 parts by weight, the bendability of the pattern may be lowered.

Further, the resist composition according to the present invention may further contain an additive for the purpose of improving coatability and the like.

The additive is not particularly limited as long as it is generally applicable to the resist composition, and specific examples thereof include an alkaline dissolution inhibitor, an acid diffusion inhibitor, a surfactant, and the like. A single type, or a mixture of two or more types.

The alkaline dissolution inhibitor can be used as long as it is generally applicable to the alkaline dissolution inhibitor of the resist composition, and specific examples thereof include a phenol or a carboxylic acid derivative.

The acid diffusion inhibitor functions to suppress diffusion and development of an acid generated from an acid generator by diffusion of light to a resist film by light irradiation, thereby suppressing a chemical reaction in an unexposed portion. By using such an acid diffusion inhibitor, the storage stability of the radiation-sensitive linear resin composition can be improved, and the resolution of the resist can be further improved, and the time (PED) from the exposure to the development processing can be suppressed. The line width of the resist pattern changes.

As the acid diffusion inhibitor, a basic compound can be used, and specific examples thereof include ammonia, methylamine, isopropylamine, n-hexylamine, cyclopentylamine, methylenediamine, ethylenediamine, and dimethylamine. Diisopropylamine, diethylenediamine, N,N-dimethyldiamine, N,N-dimethylethylenediamine, trimethylamine, triethylamine, N,N,N',N'-tetra Methyldiamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethyltetraethylenepentamine,diethylamine,methylethyl Propylamine, benzylamine, phenethylamine, benzyldimethylamine, tetramethylhydrogen Ammonium oxide, aniline, N,N-dimethylanilinium triphenylamine, phenylenediamine, pyrrole, oxazole, isoxazole, thiazole, isothiazole, imidazole, pyrazole, pyrroline, pyrrolidine, imidazoline derived , imidazolidine derivative, pyridine derivative, pyridazine derivative, pyrimidine derivative, pyrazine derivative, pyrazoline derivative, pyrazolidine derivative, acridine derivative, pyridazine derivative, morpholine, etc. Amines, amino acids, hydrazine carboxylic acids, amino acid derivatives (such as niacin, alanine, arginine, aspartic acid, etc.), 3-pyridine sulfonic acid, p-toluenesulfonic acid pyridinium salt, 2-hydroxypyridine Nitrogen compounds such as aminom-cresol, 2,4-quinolinediol, 2-(2-hydroxyethyl)pyridine, 1-(2-hydroxyethyl)pyridazine, formamide, N-methyl Indoleamine derivatives such as decylamine, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide Or a quinone imine derivative such as phthalimide, amber imine or maleimine.

The content of the above acid diffusion inhibitor may be 0.01 to 5 parts by weight, preferably 0.1 to 1 part by weight, based on 100 parts by weight of the polymer solid content. If the content of the acid diffusion inhibitor is less than 0.01 parts by weight, the influence on the delay time after exposure may be large, which may affect the image shape. If it exceeds 5 parts by weight, the resolution and sensitivity may be lowered.

The surfactant is used for improving coatability and developability, and specific examples thereof include polyoxyethylene lauryl ether, octadecyl polyoxyethylene ether, polyoxyethylene, and polyethylene glycol dilaurate. However, it is not limited to this.

When a resist pattern is formed by using the resist composition of the present invention having the composition as described above, an improved line width roughness is exhibited, and both the C/H pattern and the L/S pattern are excellent. Resolution. In addition, since it has a good process window, an excellent pattern profile can be obtained regardless of the type of substrate, and an improved contrast is exhibited. Therefore, the above resist composition is induced by X-rays such as KrF excimer laser, ArF excimer laser or F2 excimer laser such as far ultraviolet rays, synchrotron radiation, and charged particles such as EUV. It is useful for chemically amplified positive photoresist compositions.

According to still another embodiment of the present invention, there is provided a method of forming a pattern using the above resist composition.

Specifically, the method of forming the above-described pattern includes the steps of: forming a resist film by coating the above resist composition on a substrate; and performing a step of exposing in a predetermined pattern after heat-treating the resist film; and developing is exposed The steps of the resist pattern.

A wafer substrate can be used for the substrate, and a method of applying the substrate can be performed by a method such as spin coating, flow coating, or roll coating.

Specifically, a film thickness of 0.3 to 2.0 μm is coated on a substrate such as a tantalum wafer, which is prebaked at 60 to 150 ° C for 1 to 10 minutes, preferably at 80 to 130 ° C for 1 to 5 minutes.

Next, in order to form a fine pattern, a part of the resist film is irradiated with radiation. In this case, the radiation that can be used is not particularly limited, but an I-ray of ultraviolet rays, a KrF excimer laser of far ultraviolet rays, an ArF excimer laser, an F2 excimer laser, an X-ray, and an electron beam of a charged particle beam can be used. Etc., depending on the type of the acid generator, it can be appropriately selected and used.

Specifically, the irradiation radiation is irradiated so that the irradiation energy at the time of exposure is about 1 to 200 mJ/cm ² , preferably about 10 to 100 mJ/cm ² , and then post-exposure baking (PEB) at 60 to 150 ° C for 1 to 5 minutes, preferably. Bake at 80 to 130 ° C for 1 to 3 minutes after exposure.

The resist pattern exposed after the exposure step is subjected to development by a dipping method, a puddle method, a spray method, or the like, by soaking for 0.1 to 3 minutes, preferably 0.5 to 2 minutes. Thereby forming a desired pattern on the substrate.

In this case, the developer is not particularly limited as long as it is a developer which is usually used as a reversal developer. Specifically, a ketone solvent (for example, acetone, methyl ethyl Ketone, methyl isobutyl ketone, acetamidine acetone, etc.; ester solvent (for example, methyl acetate, n-butyl acetate, propylene glycol monomethyl ether acetate, methyl formate, ethyl lactate, etc.); alcohol Solvents (methanol, ethylene glycol, ethylene glycol monomethyl ether, etc.); guanamine solvents (N-methyl-pyrrolidone, N,N-dimethylformamide, etc.); ether solvents (dioxane) A polar solvent such as tetrahydrofuran or the like may be used, or a hydrocarbon solvent (for example, toluene, xylene, pentane, hexane, or the like) may be used as the organic developer, and one or more of the above developer may be used in combination, or may be mixed with water. . Among them, n-butyl acetate is preferred. At this time, the developer may further contain a surfactant as needed.

By the method of forming a pattern by the resist composition according to the present invention as described above, it is possible to form a fine resist pattern having excellent sensitivity and resolution.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail so as to be easily implemented by those skilled in the art to which the present invention pertains. However, the invention may be embodied in a variety of different forms and is not limited to the embodiments described herein.

Polymer Synthesis Example 1 .

step 1.

In a 1L jacket type reaction vessel, 360 g of 1,4-dioxane was used as a polymerization solvent to dissolve 3-hydroxyadamantane-1-yl methacrylate (3-hydroxyadamantan). -1-yl methacrylate) (i) 120g and azobisisobutyronitrile as initiator (azobisbutyronitril, AIBN) 6.5 g, and then the temperature of the reaction vessel was raised to 75 ° C and stirred for three hours. After cooling the obtained polymerization solution to normal temperature, n-hexane (n-hexane) was gradually added dropwise to carry out a precipitation reaction. The precipitate obtained was filtered under reduced pressure using a vacuum screening procedure, and dried under reduced pressure for one day to prepare 95 g of HAMA homopolymer (ii).

The obtained polymer had a polystyrene-equivalent weight average molecular weight (Mw) of 4955 g/mol, and a ratio of weight average molecular weight to number average molecular weight (Mw/Mn) of 1.64.

Step 2.

In the above formula, a = 0.5 and b = 0.5.

20 g of the HAMA homopolymer (ii) prepared in the above step 1 was dissolved in 200 ml of tetrahydrofuran (THF), and the amount to be substituted (for preparing ethyl vinyl ether 50% replacement) was added. Ethyl vinyl ether in an amount of 3.05 g) and a catalytic amount of trifluoroacetic acid were stirred at room temperature for two days. After confirming the termination of the reaction by 1H NMR, the obtained polymerization solution was added dropwise to n-hexane as a precipitating solvent to carry out a precipitation reaction. The obtained precipitate was filtered under reduced pressure using a vacuum screening procedure, and dried under reduced pressure for one day to obtain 16 g of a polymer (1a).

The obtained polymer had a polystyrene-equivalent weight average molecular weight (Mw) of 7144 g/mol, and a ratio of weight average molecular weight to number average molecular weight (Mw/Mn) of 1.34.

¹ H NMR (CDCl ₃ , internal standard: tetramethyl decane): (ppm) 0.8 to 2.4 ppm (m, 46H), 3.4 to 3.6 ppm (d, 2H), 5 ppm (1H).

Polymer Synthesis Examples 2 to 5 .

The displacement reaction was carried out except that the amount of ethyl vinyl ether added as a reactant was changed to 10% (0.81 g), 30% (2.44 g), 70% (5.69 g), and 100% (8.1 g), respectively. The polymer was prepared in the same manner as in the above Polymer Synthesis Example 1 except for the above.

Polymer Synthesis Example 6 .

20 g of the HAMA homopolymer (ii) prepared in the above step 1 of the polymer synthesis example 1 was dissolved in 200 ml of tetrahydrofuran (THF), followed by the addition of 3.05 g of t-butyl vinyl ether and a catalytic amount of trifluoroethylene. Trifluoroacetic acid was stirred at room temperature for two days. After confirming the termination of the reaction by 1H NMR, the obtained polymerization solution was added dropwise to n-hexane as a precipitating solvent to carry out a precipitation reaction. The obtained precipitate was filtered under reduced pressure using a vacuum screening procedure, and dried under reduced pressure for one day to obtain 15 g of a polymer (1c).

Polymer Synthesis Example 7 .

20 g of the HAMA homopolymer (ii) prepared in the above step 1 of the polymer synthesis example 1 was dissolved in 200 ml of tetrahydrofuran (THF), followed by the addition of 3.05 g of 3,4-dihydro-2H-pyran. (3,4-Dihydro-2H-pyran) and a catalytic amount of trifluoroacetic acid (trifluoroacetic) Acid), stir at room temperature for two days. After confirming the termination of the reaction by 1H NMR, the obtained polymerization solution was added dropwise to n-hexane as a precipitating solvent to carry out a precipitation reaction. The precipitate obtained was filtered under reduced pressure using a vacuum screening procedure, and dried under reduced pressure for one day to obtain 15.5 g of a polymer (1d).

Polymer Synthesis Example 8 .

20 g of the HAMA homopolymer (ii) prepared in the above step 1 of the polymer synthesis example 1 was dissolved in 200 ml of tetrahydrofuran (THF), followed by the addition of 3.05 g of cyclohexyl vinyl ether and a catalytic amount of trifluoroethylene. Trifluoroacetic acid was stirred at room temperature for two days. After confirming the termination of the reaction by 1H NMR, the obtained polymerization solution was added dropwise to n-hexane as a precipitating solvent to carry out a precipitation reaction. The precipitate obtained was filtered under reduced pressure using a vacuum screening procedure, and dried under reduced pressure over a day to give 16.3 g of polymer (1e).

Compare the polymerization example 1 .

25 g of methyl adamantine methacylate of the polymerization monomer, 19.2 g of γ-butyrolactone methacrylate, and hydroxy 26.2 g of hydroxyl adamantane methacrylate and 4 g of dimethyl azobis isobutylate as a polymerization initiator and 200 g of 1,4-dioxane (1,4- The dioxane) was poured into a flask and mixed, and then the inside of the flask was replaced with nitrogen gas with nitrogen, and the internal temperature of the reactor was heated to 70 °C. The reaction was carried out at the same temperature for 5 hours. After completion of the polymerization reaction, the obtained reaction solution was cooled to normal temperature, and the reaction solution cooled to normal temperature was subjected to a precipitation reaction with an excess amount of hexane, followed by filtration and separation. The separated filtrate was washed with the same solvent and dried under reduced pressure. As a result, 55 g of the random copolymer of the following Chemical Formula 9 was obtained. The obtained copolymer had a polystyrene-equivalent weight average molecular weight (Mw) of 7,840 g/mol, and a ratio of weight average molecular weight to number average molecular weight (Mw/Mn) of 1.93.

In the above formula, l/m/n = 40/30/30.

Test Example 1 .

In order to observe whether it can be used as a polymer for NTD, the polymer prepared in Synthesis Examples 1 to 5 by the above polymer was tested using n-butyl acetate as a solvent for NTD photoresist. From the results, the solubility corresponding to the substitution ratio of the ethyl vinyl ether-substituted hydroxyl group was evaluated.

Specifically, 1 g of the polymer having a different substitution ratio prepared in the above polymer synthesis examples 1 to 5 was dissolved in 10 ml of n-butyl acetate, and the solubility was observed after 30 minutes. The results are shown in Table 1 below. At this time, the solubility was evaluated by the following criteria.

evaluation standard:

1: completely insoluble 2: dissolved a little 3: general 4: most dissolved 5: completely dissolved.

1: The degree to which an OH group is substituted with a vinyl ether group when HAMA is regarded as 100%.

As shown in the above Table 1, it can be confirmed that the HAMA (hydroxy adamantane methacrylate) homopolymer is completely insoluble in n-BA, and as the ethyl vinyl ether substitution rate of the hydroxyl group increases, the solubility for n-BA becomes more and more The more you increase. Further, similar effects were obtained also for the polymers prepared in Polymer Synthesis Examples 6 to 9.

Test Example 2 .

In order to evaluate the use of the polymer according to the present invention, a resist film was formed by the polymer prepared in the above Polymer Synthesis Example 1 when a resist film was formed, and the thickness loss due to the difference in energy was used.

Specifically, 5 parts by weight of triphenylsulfonium perfluorobutanesulfonate and 1.5 parts by weight in 1000 parts by weight of propylene glycol methyl ether acetate were dissolved with respect to 100 parts by weight of the polymer obtained in Polymer Synthesis Example 1. A part by weight of an alkaline additive, tetramethylammonium hydroxide, was filtered using a 0.2 μm membrane screening procedure to prepare a resist. The prepared resist liquid was coated on a substrate by a spinner and dried at 110 ° C for 90 seconds. A film having a thickness of 0.20 μm was formed. The formed film was exposed to light using an ArF excimer laser (number of lens openings: 0.78), and then heat-treated at 110 ° C for 90 seconds. Then, development, washing, and drying were carried out using n-butyl acetate for 40 seconds to form a resist pattern. At this time, the thickness loss caused by changing the different energies to the formed resist pattern was observed. Further, for the sake of comparison, the polymer of Chemical Formula 9 prepared in the above Comparative Polymerization Example was used.

The results are shown in Fig. 1 below.

FIG. 1 is a graph showing a result of thickness loss caused by observation of energy change.

As shown in FIG. 1, when a resist pattern was formed using the HAMA homopolymer prepared in Polymer Synthesis Example 1 as compared with the case of using the random copolymer prepared in Comparative Polymerization Example 1 The inclination of the thickness loss curve due to the change in energy is vertical, so that it can be confirmed that the contrast is improved.

The preferred embodiments of the present invention have been described in detail above, but the scope of the claims of the present invention is not limited thereto, and various modifications and improvements of the basic concept of the present invention as defined in the appended claims also belong to the present invention. Within the scope of the invention.

Claims (11)

A polymer for a resist which is a homopolymer of a hydroxy-containing adamantyl (meth) acrylate in which a hydroxyl group is partially or completely substituted with an acetal group. The resist polymer according to claim 1, wherein the resist polymer has a structure of the following Chemical Formula 1: In the above Chemical Formula 1, R is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; X _a and X _b are each independently an adamantane-diyl group; and R ₁ to R ₃ are each independently selected from a hydrogen atom and carbon. a group consisting of an alkyl group having 1 to 20 atoms, a cycloalkyl group having 3 to 30 carbon atoms, and a combination thereof, or an adjacent functional group is bonded to form a carbon atom having 3 to 30 carbon atoms. a cycloalkyl group, or an oxygen group bonded to R ₂ , forms a heterocycloalkyl group having 2 to 30 carbon atoms, and a and b satisfy a+b=1, 0 a/(a+b)<1 and 0<b/(a+b) 1. The polymer for resist according to claim 1, wherein the polymer for the resist is selected from the group consisting of the compounds of the following Chemical Formulas 1a to 1e: In the above chemical formulae 1a to 1e, a and b satisfy the condition of a + b = 1, 0 a/(a+b)<1 and 0<b/(a+b) 1. The resist polymer according to claim 1, wherein the resist polymer has a weight average molecular weight of from 1,000 to 100,000 g/mol in terms of polystyrene conversion by gel permeation chromatography (GPC). The resist polymer according to claim 1, wherein the resist polymer has a molecular weight distribution, that is, a ratio (Mw/Mn) of a weight average molecular weight to a number average molecular weight of 1 to 3. A resist composition, wherein the resist composition contains the polymer for a resist according to claim 1. The resist composition according to claim 6, wherein the resist composition for reversal development. The resist composition of claim 6, wherein the resist polymer is contained in an amount of from 3 to 20% by weight based on the total weight of the resist composition. A method for forming a resist pattern, comprising the steps of: coating a resist composition according to claim 6 on a substrate to form a resist film; and performing heat treatment on the resist film, The step of exposing to a prescribed pattern; and the step of developing the exposed resist pattern. The method for forming a resist pattern according to claim 9, wherein the exposure process is performed by using a group selected from the group consisting of KrF excimer laser, ArF excimer laser, extreme ultraviolet laser, X-ray, and electron beam. The light source is implemented. The method of forming a resist pattern according to claim 9, wherein the developing is performed using a reverse type organic developing solution.