JP4023743B2 - Novel acrylic or methacrylic acid ester and polymer or copolymer thereof - Google Patents

Description

  The present invention relates to a novel acrylic or methacrylic acid ester and a polymer or copolymer thereof.

Conventionally, the resin component of the chemically amplified resist has mainly been polyhydroxystyrene having high transparency with respect to KrF excimer laser light (248 nm) and those obtained by protecting this hydroxyl group with an acid dissociable, dissolution inhibiting group. Has been.
However, in recent years, the demand for miniaturization of semiconductor elements is increasing, and the light source is also shifting from KrF excimer laser light to a process using ArF excimer laser light (193 nm) having a shorter wavelength.

  By the way, in a process using ArF excimer laser light (193 nm) as a light source, a resin having an aromatic ring such as polyhydroxystyrene, which has been conventionally used, is insufficient in transparency to ArF excimer laser light and cannot be used. As an alternative, acrylic resins having no aromatic ring have attracted attention. However, this acrylic resin has a drawback of low dry etching resistance.

  As an improvement of such drawbacks, an acrylic resin having both transparency and dry etching resistance, such as a polymer of an acrylate ester having an adamantane skeleton in the ester portion (see Patent Document 1), and an ester portion A copolymer of an acrylate ester having an adamantane skeleton and a tetrahydropyranyl acrylate ester (see Patent Document 2) has been proposed. To introduce an acrylate ester having an adamantane skeleton as a constituent unit Since special raw materials have to be used, the cost is unavoidable, and these have the disadvantages of low sensitivity and poor resist pattern shape, making it difficult to industrialize.

  On the other hand, in the process using ArF excimer laser light, it is an important purpose to form an ultrafine pattern of 0.2 μm or less with good resolution. In the photoresists up to this point, the adhesion between the substrate and the resist layer is insufficient, and pattern collapse occurs.

  For this reason, the introduction of an acrylic acid ester having an oxygen-containing heterocyclic group such as 3-oxocyclohexyl ester of acrylic acid (see Patent Document 3) and γ-butyrolactone (see Patent Document 4) as a structural unit is proposed. However, the acrylic resin introduced with an acrylate ester unit having such an oxygen-containing heterocyclic group is somewhat improved in terms of adhesion, but the production process is complicated and mass production is difficult. In addition, in the paddle development which is the mainstream of semiconductor device manufacturing, a faithful resist pattern cannot be formed because the affinity for an aqueous alkali solution used as a developer is insufficient. For this reason, the advent of an ArF excimer laser light resist having excellent adhesion to a substrate and having an affinity for an aqueous alkali solution capable of paddle development is desired in this field.

  In addition, it forms an ester with acrylic acid at the β-position in the lactone ring, such as mevalonic lactone, and an acrylate ester with improved detachability by introducing an alkyl group into the β-position carbon. Although what is made into a unit is also known (refer patent document 5), since this does not have sufficient contrast of an exposure part and an unexposed part, neither sensitivity nor resolution is satisfactory.

JP-A-4-39665 (Claims and others) JP-A-5-265212 (Claims and others) JP-A-5-346668 (Claims and others) Japanese Patent Laid-Open No. 7-181677 (Claims and others) JP-A-9-90637 (Claims and others)

  Under such circumstances, the present invention is highly transparent to ArF excimer laser light, has high sensitivity and high resolution, and has high affinity for alkali. It was made for the purpose of providing a novel acrylic or methacrylic acid ester suitable for use in a positive photoresist composition capable of obtaining a pattern with good dry etching and adhesion, and a polymer and copolymer thereof. is there.

The present inventors have made intensive studies to develop a positive photoresist composition for ArF excimer laser, the ester moiety, a branched alkyl group lactone compound is bonded, novel acrylic especially isopropyl A positive photoresist composition in which a polymer or copolymer of an acid ester or methacrylic acid ester is highly transparent to ArF excimer laser light, has high sensitivity, high resolution, and forms an excellent physical property pattern And the present invention has been completed based on this finding.

（式中のＲ¹は水素原子又はメチル基、Ｒ²及びＲ³は、それぞれ炭素数１〜４の低級アルキル基、Ｒ⁴はラクトン化合物の中から選ばれた化合物の炭素原子に結合した水素原子１個を除いて形成される残基である）
で表わされるアクリル若しくはメタクリル酸エステルを提供することである。 That is, the first object of the present invention is the following general formula.

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are each a lower alkyl group having 1 to 4 carbon atoms, and R ⁴ is a hydrogen bonded to a carbon atom of a compound selected from lactone compounds. A residue formed by removing one atom)
An acrylic or methacrylic acid ester represented by:

In formula (I), lower alkyl group having 1 to 4 carbon atoms represented by R ² and R ³ may be linear or branched, for example, methyl, ethyl radical, n -Propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group and the like.

In the present invention, both R ² and R ³ are required to be a lower alkyl group having 1 to 4 carbon atoms , and if either or both of them are hydrogen atoms, the object of the present invention cannot be achieved. R ² and R ³ may be any of the above lower alkyl groups, and are not limited. However, those that are both methyl groups are preferred from the standpoint of availability.

On the other hand, the residues formed by removing one hydrogen atom bonded to the carbon atom of the lactone compound of R ⁴ include γ-butyrolactone residue, δ-valerolactone residue, and derivatives thereof. Can be mentioned. Here, examples of the derivative include a lower alkyl substituent having 1 or 2 carbon atoms such as a methyl group and an ethyl group, a lower alkoxy substituted having 1 or 2 carbon atoms such as a methoxy group and an ethoxy group, and a plurality of oxygen atoms on a lactone ring. And those having a lactone ring bonded to a methoxycarbonyl group or an acyl group. Among these, a γ-butyrolactone residue and a γ-butyrolactone residue having the above lower alkyl group or lower alkoxy group are preferred.

で表わされる化合物を挙げることができる。これらの中で五員環のラクトン残基を有するアルコールが好ましい。 In the acrylic acid ester or methacrylic acid ester represented by the general formula (I), as the alcohol component having the lactone compound residue, for example,

The compound represented by these can be mentioned. Alcohols having a lactone residue of five-membered rings among these are not preferable.

（式中のＲ¹は水素原子又はメチル基である）
で表わされるアクリル又はメタクリル酸エステルを提供することである。 The second object of the present invention is to formula

(R ¹ in the formula is a hydrogen atom or a methyl group )
An acrylic or methacrylic acid ester represented by:

（式中のＲ¹は水素原子又はメチル基、Ｒ²及びＲ³は、それぞれ炭素数１〜４の低級アルキル基、Ｒ⁴はラクトン化合物の中から選ばれた化合物の炭素原子に結合した水素原子１個を除いて形成される残基である）
で表わされる構成単位を含むアクリル若しくはメタクリル系重合体又は共重合体を提供することである。 The third object of the present invention is to provide a general formula

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are each a lower alkyl group having 1 to 4 carbon atoms, and R ⁴ is a hydrogen bonded to a carbon atom of a compound selected from lactone compounds. A residue formed by removing one atom)
An acrylic or methacrylic polymer or copolymer containing a structural unit represented by:

（式中のＲ¹は水素原子又はメチル基である）
で表わされる構成単位を含むアクリル系若しくはメタクリル系重合体又は共重合体を提供することである。 The fourth object of the present invention is to formula

(R ¹ in the formula is a hydrogen atom or a methyl group)
To provide an acrylic or methacrylic polymer or copolymer comprising a structural unit represented in.

The acrylic acid or methacrylic acid ester represented by the general formula (II) of the present invention is obtained by esterifying acrylic acid or methacrylic acid with a corresponding alcohol, and can be produced inexpensively and easily. Suitable for mass production.

  Next, the polymer of the present invention can be obtained by polymerizing the monomer represented by the general formula (I) or (II) alone. In the copolymer of the present invention, two of the monomers represented by the general formula (I) or (II) may be copolymerized, or this monomer and another monomer may be copolymerized. .

  In this case, the other monomer to be copolymerized has, for example, (a-1) a protective group such as a known dry etching resistance improving group or acid dissociable group conventionally used in chemically amplified positive photoresists. Acrylic or methacrylic acid derivative, (a-2) carboxylic acid having an ethylenic double bond for alkali solubility such as acrylic or methacrylic acid, maleic acid, fumaric acid, (a-3) a monomer known as an acrylic resin Examples thereof include acrylic monomers having components and (a-4) other oxygen-containing cyclic groups. These other monomers may be used in appropriate combination.

  Examples of the monomer (a-1) include tert-butyl acrylate or methacrylate, acrylic or tetrahydropyranyl methacrylate, acrylic or tetrahydrofuranyl methacrylate, acrylic or 1-methylcyclohexyl methacrylate, acrylic or 2-methyl methacrylate. Acrylic or methacrylic acid ester in which the hydroxyl group of the carboxyl group such as adamantyl, acrylic or ethoxyethyl methacrylate, acrylic or methoxypropyl methacrylate, acrylic or methacrylic acid and 2-hydroxy-3-pinanone ester is protected with an acid-dissociable substituent Or acrylic or adamantyl methacrylate, acrylic or cyclohexyl methacrylate, acrylic or naphthyl methacrylate Acrylic or benzyl methacrylate, acrylic or 3-oxocyclohexyl methacrylate, acrylic or bicyclo [2,2,1] heptyl methacrylate, acrylic or tricyclodecanyl methacrylate, acrylic or ester of methacrylic acid and terpineol, acrylic or Examples thereof include those in which the hydroxyl group of a carboxyl group such as an ester of methacrylic acid and 3-bromoacetone is protected with an acid non-dissociable substituent.

（式中のＲ¹は水素原子又はメチル基、Ｙはｔｅｒｔ‐ブチル基、エトキシエチル基、メトキシプロピル基、テルピネオール残基又は

で示される基である）
で表わすことができる。 Such a monomer (a-1) has, for example, the general formula

(Wherein R ¹ is a hydrogen atom or a methyl group, Y is a tert-butyl group, an ethoxyethyl group, a methoxypropyl group, a terpineol residue, or

Is a group represented by
It can be expressed as

Examples of the monomer (a-2) include acrylic or methacrylic acid, maleic acid, and fumaric acid. Among these, acrylic or methacrylic acid is preferable.
Further, (a-3) monomers include, for example, (a) acrylic or methyl methacrylate, acrylic or ethyl methacrylate, acrylic or propyl methacrylate, acrylic or isopropyl methacrylate, acrylic or n-butyl methacrylate, acrylic or methacrylic Isobutyl acid, acrylic or n-hexyl methacrylate, acrylic or octyl methacrylate, acrylic or 2-ethylhexyl methacrylate, acrylic or lauryl methacrylate, acrylic or 2-hydroxyethyl methacrylate, acrylic or 2-hydroxypropyl methacrylate, etc. Alkyl esters, (b) acrylic or methacrylamide, N-methylolacrylic or methacrylamide, diacetate Amides such as acrylamide, mention may be made of (c) acrylonitrile, methacrylonitrile, vinyl chloride, and ethyl vinyl ether.

（式中のＲ⁶、Ｒ⁷及びＲ⁸は、それぞれ水素原子、低級アルキル基又は低級アルコキシ基、ｎは０又は１であり、Ｒ¹は前記と同じ意味をもつ）
で表わされるアクリル若しくはメタクリル酸エステルが用いられる。このアクリル若しくはメタクリル酸エステルのアルコール成分を形成するアルコール又はエチレン性二重結合化合物として、例えば式

で示される化合物がある。
この一般式（ＶＩ）で表わされるアクリル若しくはメタクリル酸エステルのうち、ｎが１でＲ⁶及びＲ⁷がともにメチル基であるもの、またｎが１でＲ⁸が水素原子であるものがアルカリに対する親和性に特に優れ、パドル現像に好適であるので特に好ましい。 Examples of the acrylic monomer having another oxygen-containing cyclic group (a-4) include (d) general formula

(Wherein R ⁶ , R ⁷ and R ⁸ are each a hydrogen atom, a lower alkyl group or a lower alkoxy group, n is 0 or 1, and R ¹ has the same meaning as above)
An acrylic or methacrylic acid ester represented by As an alcohol or an ethylenic double bond compound that forms the alcohol component of the acrylic or methacrylic acid ester, for example, the formula

There is a compound represented by
Among the acrylic or methacrylic acid esters represented by the general formula ( VI ), those in which n is 1 and R ⁶ and R ⁷ are both methyl groups, and those in which n is 1 and R ⁸ is a hydrogen atom are for alkali. It is particularly preferable because it is particularly excellent in affinity and suitable for paddle development.

（式中のＬはメチレン基又はアルキル置換メチレン基であり、Ｒ¹は前記と同じ意味をもつ）
で表わされるアクリル若しくはメタクリル酸エステルも用いることができる。このアクリル若しくはメタクリル酸エステルのアルコール部分を形成するエチレン性二重結合含有化合物としては、例えば、式

で示される化合物がある。 (E) General formula

(In the formula, L is a methylene group or an alkyl-substituted methylene group, and R ¹ has the same meaning as described above.)
An acrylic or methacrylic acid ester represented by the formula can also be used. Examples of the ethylenic double bond-containing compound that forms the alcohol part of the acrylic or methacrylic acid ester include, for example, the formula

There is a compound represented by

（式中のＲ⁹は水素原子又は低級アルキル基、Ｕは酸素原子、メチレン基又はアシル基を有するメチレン基、Ｔはメチレン基、アルキル置換メチレン基又はカルボニル基であり、Ｒ¹は前記と同じ意味をもつ）
で表わされるアクリル若しくはメタクリル酸エステルも用いることができる。このアクリル若しくはメタクリル酸エステルのアルコール部分を形成するエチレン性二重結合含有化合物として、例えば、式

で示される化合物がある。 Furthermore (f) General formula

(Wherein R ⁹ is a hydrogen atom or a lower alkyl group, U is an oxygen atom, a methylene group having an methylene group or an acyl group, T is a methylene group, an alkyl-substituted methylene group or a carbonyl group, and R ¹ is the same as above) Has meaning)
An acrylic or methacrylic acid ester represented by the formula can also be used. Examples of the ethylenic double bond-containing compound that forms the alcohol portion of the acrylic or methacrylic acid ester include, for example, the formula

There is a compound represented by

The copolymer in the present invention is selected from the monomer represented by the general formula (II) and the monomers (a-1), (a-2), (a-3) and (a-4). Preferred is a copolymer obtained by polymerizing at least one selected from the group consisting of a monomer represented by general formula (II) and at least selected from (a-1) and (a-4). A copolymer obtained by polymerizing one kind, particularly an acrylic or methacrylic acid ester represented by the general formula ( VI ) or an acrylic or methacrylic acid ester of 2-hydroxy-3-pinanone is preferred.

  In the copolymer, monomer units of 20 to 80 mol%, preferably 40 to 70 mol%, and at least one monomer unit selected from (a-1) and (a-4) 80 to A copolymer comprising 20 mol%, preferably 60 to 30 mol%, gives a positive photoresist having excellent dry etching resistance, adhesion, and contrast between the unexposed and exposed areas.

When preparing a positive photoresist, the polymer or copolymer of the present invention is used together with an acid generator that generates an acid upon irradiation.
The acid generator can be arbitrarily selected from compounds known so far as acid generators for chemically amplified resists.
Examples of such compounds include the following.

(I) bissulfonyldiazomethane;
Bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.

(Ii) a nitrobenzyl derivative;
p-toluenesulfonic acid 2-nitrobenzyl, p-toluenesulfonic acid 2,6-dinitrobenzyl and the like.

(Iii) sulfonate esters;
Pyrogallol trimesylate, pyrogallol tritosylate, etc.

(Iv) Onium salts;
Diphenyliodonium hexafluorophosphate, (4-methoxyphenyl) phenyliodonium trifluoromethanesulfonate, bis (p-tert-butylphenyl) iodonium trifluoromethanesulfonate, triphenylsulfonium hexafluorophosphate, (4-methoxyphenyl) diphenylsulfonium trifluoro Lomethanesulfonate, (p-tert-butylphenyl) diphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, and the like.

(V) benzoin tosylate and alkyl-substituted products thereof;
Benzoin tosylate, α-methylbenzoin tosylate, etc.

(Vi) a halogen-containing triazine compound;
2- (4-Methoxyphenyl) -4,6- (bistrichloromethyl) -1,3,5-triazine, 2- (4-methoxynaphthyl) -4,6- (bistrichloromethyl) -1,3 5-triazine, 2- [2- (2-furyl) ethenyl] -4,6- (bistrichloromethyl) -1,3,5-triazine, 2- [2- (5-methyl-2-furyl) ethenyl ] -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- [2- (3,5-dimethoxyphenyl) ethenyl] -4,6-bis (trichloromethyl) -1,3 5-triazine, 2- [2- (3,4-dimethoxyphenyl) ethenyl] -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (3,4-methylenedioxyphenyl) -4,6-bis (trichloromethyl) ) -1,3,5-triazine, 2,4,6-tris (dibromopropyl) -1,3,5-triazine, tris (2,3-dibromopropyl) -1,3,5-triazine, tris ( 2,3-dibromopropyl) isocyanurate and the like.

(Vii) an oxime sulfonate having a cyano group;
α- (Methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -4-methoxyphenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino ) -4-Methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -4-methoxyphenylacetonitrile, α- (propylsulfonyloxyimino) -4-methylphenylacetonitrile, α- (methylsulfonyloxyimino) -4-bromo Phenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- [1- (or 2-) naphthylsulfonyloxyimino] -4-methoxybenzylcani , Alpha-(10- camphorsulfonyl) -4-methoxybenzyl cyanide, alpha-(p-toluenesulfonyloxy imino) - phenylacetonitrile, alpha-phenylsulfonyl such oxyimino -p- methoxyphenyl acetonitrile.

  Particularly preferred among these acid generators are onium salts and oxime sulfonates having a cyano group. The blending ratio of the polymer or copolymer of the present invention and the acid generator is usually 0.5 to 30 parts by weight, preferably 1 to 10 parts by weight with respect to 100 parts by weight of the former. If the amount is less than this range, it is difficult to form an image.

  In addition to the polymer or copolymer of the present invention and an acid generator, the positive type photoresist includes, as desired, additive components commonly used in ordinary chemically amplified photoresists, such as antihalation agents, antioxidants, and the like. An agent, a heat stabilizer, an adhesion improver, a plasticizer, a colorant, a surfactant, an additional resin, an organic carboxylic acid, an amine, and the like may be added in an amount that does not impair the properties of the composition of the present invention. it can.

  The positive photoresist prepared in this manner is preferably used in the form of a solution in which the above components are dissolved in a solvent. Examples of such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, 2-heptanone, ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, Polypropylene and its derivatives such as dipropylene glycol or dipropylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether, cyclic ethers such as dioxane, lactic acid Methyl, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methoxypropionate Can be exemplified Le, esters such as ethyl ethoxypropionate. These may be used alone or in combination of two or more.

  If this positive photoresist is used, a pattern can be formed as follows, for example. That is, this photoresist is applied on a substrate such as a silicon wafer, pre-baked at 70 to 150 ° C. for 30 to 150 seconds to form a resist layer, and then irradiated with radiation such as ArF excimer laser light through a mask. , Heating at about 70 to 150 ° C. is performed for 30 seconds to 150 seconds, and then development is performed. As the resist developer, an alkaline aqueous solution can be used. By development, the exposed portion is dissolved in the alkaline aqueous solution, and a positive pattern is obtained. As the alkaline aqueous solution, for example, an aqueous solution of tetramethylammonium hydroxide, choline, or the like can be used.

  The positive photoresist using the polymer or copolymer of the present invention has high transparency to ArF excimer laser light, high sensitivity and high resolution, and high affinity for alkali. A resist pattern having good pattern shape, dry etching resistance and adhesion can be provided.

  Next, the best mode for carrying out the present invention will be described in detail by way of examples, but the present invention is not limited to these examples.

で示されるアルコール９４．８ｇ（０．６モル）、トリエチルアミン６０ｇ（０．６モル）をテトラヒドロフラン２００ミリリットルに溶解し、十分かきまぜたのち、これにメタクリロイルクロリド６２．４ｇ（０．６モル）を０℃で１時間にわたって滴下した。
次いで、２５℃にて２４時間反応させたのち、反応液をろ過した。そのろ液の溶媒を留去し、残存生成物をジエチルエーテル３００ミリリットルに溶解し、１０重量％水酸化ナトリウム水溶液で１０回洗浄した。次いで、ｎ‐ヘプタンを溶媒としてカラムクロマトグラフィーにより精製し、無色の液体として、上記アルコールのメタクリル酸エステル（モノマーＩ）を得た。
この生成物の¹Ｈ−ＮＭＲ（溶媒：アセトン−ｄ６）を測定した結果、０．９９、１．１９、１．４〜２．７、２．８０、４．５５、５．５０、６．００ｐｐｍにピークが認められた。
また赤外吸収スペクトルによる分析の結果、１７５５、１７７７ｃｍ^-1にカルボニルに由来するピークが認められた。 Monomer I production formula

94.8 g (0.6 mol) of alcohol represented by the formula (1) and 60 g (0.6 mol) of triethylamine were dissolved in 200 ml of tetrahydrofuran, and the mixture was sufficiently stirred, and 62.4 g (0.6 mol) of methacryloyl chloride was added to It was dripped at 1 degreeC over 1 hour.
Subsequently, after making it react at 25 degreeC for 24 hours, the reaction liquid was filtered. The solvent of the filtrate was distilled off, and the remaining product was dissolved in 300 ml of diethyl ether and washed 10 times with a 10 wt% aqueous sodium hydroxide solution. Subsequently, it was purified by column chromatography using n-heptane as a solvent to obtain a methacrylic acid ester (monomer I ) of the alcohol as a colorless liquid.
As a result of measuring ¹ H-NMR (solvent: acetone-d6) of this product, 0.99, 1.19, 1.4 to 2.7, 2.80, 4.55, 5.50, 6. A peak was observed at 00 ppm.
As a result of analysis by infrared absorption spectrum, peaks derived from carbonyl were observed at 1755 and 1777 cm ⁻¹ .

で示されるメタクリル酸エステル１１．５ｇ（０．０６２５モル、全モノマーに対し、５０モル％）をテトラヒドロフラン１５０ｇに溶解し、反応開始剤としてアゾビスイソブチロニトリル０．８２ｇを加え、７５℃で３時間重合反応させた。反応終了後、反応物をｎ‐ヘプタン５リットル中に注加して重合体を析出させ、得られた共重合体を室温下で減圧乾燥した。このようにして、モノマーＩと式（Ｘ）で示されるメタクリル酸エステルとの共重合体（共重合体Ａ−１）２１．０ｇを得た。このものの重量平均分子量は１７，４００であり、分散度は２．３０であった。 Production of Copolymer A- 1 15.1 g of monomer I obtained in Example 1 (0.0625 mol, 50 mol% based on the total monomers) and formula

Is dissolved in 150 g of tetrahydrofuran, 0.82 g of azobisisobutyronitrile is added as a reaction initiator at 75 ° C. The polymerization reaction was performed for 3 hours. After completion of the reaction, the reaction product was poured into 5 liters of n-heptane to precipitate a polymer, and the obtained copolymer was dried under reduced pressure at room temperature. In this way, 21.0 g of a copolymer (copolymer A- 1 ) of the monomer I and the methacrylic acid ester represented by the formula ( X ) was obtained. This had a weight average molecular weight of 17,400 and a dispersity of 2.30.

で示されるメタクリル酸エステル１４．６ｇ（０．０６２５モル、全モノマーに対し、５０モル％）をテトラヒドロフラン１５０ｇに溶解し、反応開始剤としてアゾビスイソブチロニトリル０．８２ｇを加え、７５℃で３時間重合反応させた。反応終了後、反応物をｎ‐ヘプタン５リットル中に注加して重合体を析出させ、得られた共重合体を室温下で減圧乾燥した。このようにして、モノマー（Ｉ）と式（ＸＩ）で示されるメタクリル酸エステルとの共重合体（共重合体Ａ−２）２２．０ｇを得た。このものの重量平均分子量は１４，６００であり、分散度は２．００であった。 Production of copolymer A- 2 15.1 g of monomer I obtained in Example 1 (0.0625 mol, 50 mol% based on the total monomers) and formula

14.6 g (0.0625 mol, 50 mol% based on all monomers) represented by the following formula is dissolved in 150 g of tetrahydrofuran, and 0.82 g of azobisisobutyronitrile is added as a reaction initiator at 75 ° C. The polymerization reaction was performed for 3 hours. After completion of the reaction, the reaction product was poured into 5 liters of n-heptane to precipitate a polymer, and the obtained copolymer was dried under reduced pressure at room temperature. In this way, 22.0 g of a copolymer (copolymer A- 2 ) of a monomer ( I ) and a methacrylic acid ester represented by the formula ( XI ) was obtained. This had a weight average molecular weight of 14,600 and a dispersity of 2.00.

Production of Copolymer A- 3 In Example 2 , instead of 11.5 g of the methacrylic acid ester represented by the formula ( X ), 14.8 g (0.0625 mol) of 2-hydroxy-3-pinanone methacrylic acid ester In the same manner as in Example 2 , except that the solvent was changed from 150 g of tetrahydrofuran to 100 g of dioxane, the monomer I was co-polymerized with monomer I and 2-hydroxy-3-pinanone methacrylate. 16.3 g of a polymer (copolymer A- 3 ) was obtained. This had a weight average molecular weight of 9,200 and a dispersity of 2.6.

Reference example 1
100 parts by weight of copolymer (A-1) obtained in Example 2 and 2 parts by weight of bis (p-tert-butylphenyl) iodonium trifluoromethanesulfonate were dissolved in 680 parts by weight of propylene glycol monomethyl ether acetate to form a positive photoresist. A solution was obtained.
Next, this photoresist solution was applied on a silicon wafer using a spinner and dried on a hot plate at 100 ° C. for 90 seconds to form a resist layer having a thickness of 0.5 μm. Next, after selectively irradiating ArF excimer laser light (193 nm) with an ArF exposure apparatus (manufactured by Nikon Corporation), heat treatment was performed at 110 ° C. for 90 seconds, and then with a 2.38 wt% tetramethylammonium hydroxide aqueous solution. Paddle development was performed for 2 seconds, followed by washing with water for 30 seconds and drying.
When the exposure time in which the 0.30 μm line and space formed by such an operation is formed at 1: 1 is measured in mJ / cm ² (energy amount) unit as a sensitivity, it is 11.0 mJ / cm ² . there were.
Further, when the cross-sectional shape of the 0.25 μm resist pattern formed in this way was observed with an SEM (scanning electron microscope) photograph, it was a rectangular resist pattern perpendicular to the substrate.
Further, by such an operation, a resist pattern of 0.20 μm was resolved, and there was no pattern collapse.
Next, using tetrafluoromethane gas as an etching gas, dry etching treatment is performed with an etching apparatus OAPM-406 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), and the dry etching resistance is evaluated by the amount of film reduction per unit time. 0.0, it was 1.08 .

Reference example 2
In Reference Example 1, a positive photoresist solution was prepared in the same manner as in Reference Example 1, except that the copolymer A- 2 obtained in Example 3 was used instead of the copolymer A-1. A resist pattern was formed under the same conditions as in Reference Example 1.
The sensitivity measured in the same manner as in Reference Example 1 was 6 mJ / cm ² , and the cross-sectional shape of the formed 0.25 μm resist pattern was observed with a SEM (scanning electron microscope) photograph. It was a rectangular resist pattern perpendicular to.
Further, by such an operation, a resist pattern of 0.20 μm was resolved, and there was no pattern collapse.
Further, when the dry etching resistance was examined in the same manner as in Reference Example 1, it was 0.95.

Reference example 3
100 parts by weight of the copolymer (A- 3 ) obtained in Example 4 and 2 parts by weight of triphenylsulfonium trifluoromethanesulfonate were dissolved in 680 parts by weight of propylene glycol monomethyl ether acetate to obtain a positive photoresist solution.
Next, this photoresist solution was applied on a silicon wafer using a spinner and dried on a hot plate at 100 ° C. for 90 seconds to form a resist layer having a thickness of 0.5 μm. Next, after selectively irradiating ArF excimer laser light (193 nm) with an ArF exposure apparatus (manufactured by Nikon), heat treatment was performed at 110 ° C. for 90 seconds, and then with a 2.38 wt% tetramethylammonium hydroxide aqueous solution. Paddle development was performed for 2 seconds, followed by washing with water for 30 seconds and drying.
It was 12 mJ / cm ² when the exposure time when a 0.30 μm line and space formed by such an operation was formed as a sensitivity was measured in mJ / cm ² (energy amount) unit. .
Further, when the cross-sectional shape of the 0.25 μm resist pattern formed in this way was observed with an SEM (scanning electron microscope) photograph, it was a rectangular resist pattern perpendicular to the substrate.
Further, by such an operation, a resist pattern of 0.18 μm was resolved, and there was no pattern collapse.
Next, using tetrafluoromethane gas as an etching gas, dry etching treatment is performed with an etching apparatus OAPM-406 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), and the dry etching resistance is evaluated by the amount of film reduction per unit time. 0.0, it was 1.1.

  The polymer and copolymer of the present invention are suitably used as a resin component of a chemically amplified resist.

Claims (9)

General formula

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are each a lower alkyl group having 1 to 4 carbon atoms, and R ⁴ is a hydrogen bonded to a carbon atom of a compound selected from lactone compounds. A residue formed by removing one atom)
An acrylic or methacrylic acid ester represented by R ⁴ in the formula, .gamma.-butyrolactone residue, .delta.-valerolactone residues and acrylic or methacrylic acid ester of claim 1 wherein Ru these derivative residue der. The acrylic or methacrylic acid ester according to claim 2, wherein R ⁴ in the formula is a γ-butyrolactone residue or a γ-butyrolactone residue having a lower alkyl group having 1 or 2 carbon atoms or a lower alkoxy group. General formula

(R ¹ in the formula is a hydrogen atom or a methyl group)
The acrylic or methacrylic acid ester of Claim 1 represented by these. General formula

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are each a lower alkyl group having 1 to 4 carbon atoms, and R ⁴ is a hydrogen bonded to a carbon atom of a compound selected from lactone compounds. A residue formed by removing one atom)
An acrylic or methacrylic polymer or copolymer containing a structural unit represented by: 6. The acrylic or methacrylic polymer or copolymer according to claim 5 , wherein R ⁴ in the formula is a γ-butyrolactone residue, a δ-valerolactone residue, or a derivative residue thereof. 6. The acrylic or methacrylic polymer or copolymer according to claim 5 , wherein R ⁴ in the formula is a γ-butyrolactone residue, or a γ-butyrolactone residue having a lower alkyl group having 1 or 2 carbon atoms or a lower alkoxy group. General formula

(R ¹ in the formula is a hydrogen atom or a methyl group)
The acrylic or methacrylic polymer or copolymer according to claim 5 comprising a structural unit represented by: The acrylic or methacrylic copolymer according to any one of claims 5 to 8 , wherein the content of the structural unit represented by Chemical Formula 3 is 20 to 80 mol%.