JP4525440B2 - Radiation sensitive resin composition - Google Patents

Description

The present invention relates to a radiation sensitive resin composition. More specifically, chemicals useful for microfabrication using various types of radiation such as deep ultraviolet rays such as KrF excimer laser, ArF excimer laser or F ₂ excimer laser, X-rays such as synchrotron radiation, and charged particle beams such as electron beams. The present invention relates to a radiation sensitive resin composition that can be suitably used as an amplification resist.

In the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, recently, lithography technology capable of microfabrication at a level of 0.20 μm or less is required.
However, in the conventional photolithography process, near ultraviolet rays such as i-rays are generally used as radiation, and it is said that fine processing at a sub-quarter micron level or less is extremely difficult with this near ultraviolet rays.
Therefore, in order to enable microfabrication at a level of 0.20 μm or less, use of radiation having a shorter wavelength is being studied. Examples of such short-wave radiation include far-ultraviolet rays such as an emission line spectrum of an mercury lamp and an excimer laser, an X-ray, an electron beam, etc. Among them, in particular, a KrF excimer laser (wavelength 248 nm), An ArF excimer laser (wavelength 193 nm) or an F ₂ excimer laser (wavelength 157 nm) has attracted attention. As a radiation-sensitive resin composition suitable for these excimer lasers, a component having an acid-dissociable functional group, a radiation-sensitive acid generator that generates acid upon irradiation with radiation (hereinafter referred to as “exposure”), Many chemical amplification type radiation sensitive resin compositions utilizing the chemical amplification effect of the above have been proposed.
This chemically amplified radiation-sensitive resin composition itself is insoluble or hardly soluble in an alkaline developer, but uses a resin having an acid-dissociable group that is dissociated by the action of an acid. It is dissociated by the action of an acid generated from the radiation acid generator to form an acidic functional group such as a carboxyl group or a phenolic hydroxyl group. As a result, the phenomenon that the exposed region of the resist film becomes soluble in an alkali developer is utilized.

  In recent years, some chemically amplified radiation-sensitive resin compositions using two or more radiation-sensitive acid generators have been proposed. For example, a radiation sensitive acid generator comprising an ionic compound such as an iodonium salt compound and a nonionic compound such as an N-sulfonyloxyimide compound, and an acid sensitive site such as hydroxystyrenes and t-butyl (meth) acrylate A photoresist composition containing a copolymer with a (meth) acrylic acid ester having benzene is disclosed (see Patent Document 1). In addition, a component having a large effect of slowing the dissolution rate of the exposed portion such as a bis (triphenylsulfonium) sulfide salt compound and a small effect of slowing the dissolution rate of the exposed portion of the N-sulfonyloxyimide compound or diphenyliodonium salt compound. A positive-type photoresist composition containing a resin having an acid-dissociable group such as a radiation-sensitive acid generator composed of components and a copolymer of hydroxystyrenes and t-butoxystyrenes is disclosed ( Patent Document 2). Further, it contains an N-sulfonyloxyimide compound and a copolymer of hydroxystyrenes and styrenes having an acid dissociable acetal group, and further uses other radiation sensitive acid generators such as onium salt compounds. Moreover, the radiation sensitive resin composition etc. which this copolymer may contain t-butoxy styrene are disclosed (refer patent document 3).

JP 2000-147753 A JP-A-11-167199 Japanese Patent Laid-Open No. 11-352677

By the way, the recent photolithography process is rapidly miniaturized, and in particular, in the photolithography process using a KrF excimer laser, the limit resolution is approaching half or less of the light source wavelength. For this reason, demands for a chemically amplified radiation-sensitive resin composition as a photoresist are becoming more and more severe, and the line edge roughness (hereinafter, also referred to as “LER”) characteristics and the depth of focus margin, particularly with respect to the depth of focus margin. The demand is severe.
However, in the field of integrated circuit elements, when a higher degree of integration than before is required, conventional chemical amplification type radiation-sensitive resin compositions including those in Patent Documents 1 to 3 above, particularly LER characteristics and There is a problem that the depth of focus margin is not sufficient.

The subject of the present invention is a chemically amplified resist sensitive to far ultraviolet rays typified by actinic radiation such as KrF excimer laser, ArF excimer laser or F ₂ excimer laser, and has excellent basic physical properties such as sensitivity, in particular LER characteristics and The object is to provide a radiation-sensitive resin composition having an excellent depth of focus margin.

  The inventors of the present invention have made extensive studies to develop a radiation-sensitive resin composition having excellent basic properties such as sensitivity as well as excellent LER characteristics and depth of focus allowance as a chemically amplified resist. As a result, after the monomer mixture containing a specific monomer was copolymerized using a specific radical generator, the resulting copolymer was converted into a repeating unit having a phenolic hydroxyl group using a base catalyst. It has been found that when a converted copolymer is used, a radiation-sensitive resin composition having excellent basic properties such as sensitivity and excellent LER characteristics and depth of focus allowance can be obtained. The present invention has been made based on this finding.

（式中、Ｒ^１、Ｒ^２及びＲ^３は相互に独立に炭素数１〜４の飽和炭化水素基を示す。）

（式中、Ｒ’は水素原子又はメチル基を示す。）
２．下記一般式（３）で表される単量体及び酸解離性基を有する単量体を含む単量体混合物を、下記一般式（４）で表されるラジカル発生剤を用いて共重合させた後、一般式（３）で表される上記単量体由来の繰り返し単位を、塩基触媒を用いてフェノール性水酸基を有する繰り返し単位に変換した共重合体と、感放射線性酸発生剤と、を含有することを特徴とする感放射線性樹脂組成物。

（式中、Ｒ"は水素原子又はメチル基を示し、Ｒ^４は炭素数１〜４の飽和炭化水素基を示す。）

（式中、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、Ｒ^９及びＲ^１０は相互に独立に炭素数１〜４の飽和炭化水素基を示す。）
３．上記酸解離性基を有する単量体が、下記一般式（５）及び（６）で表される化合物から選ばれる少なくとも１種である上記２．に記載の感放射線性樹脂組成物。

（式中、Ｒ^１１は水素原子又はメチル基、Ｒ^１２、Ｒ^１３及びＲ^１４は相互に独立に炭素数１〜４の飽和炭化水素基を示す。）

［式中、Ｒ^１５は水素原子又はメチル基である。また、Ｒ^１６、Ｒ^１７及びＲ^１８は、以下の（Ａ）又は（Ｂ）のいずれかの条件を満たす。
（Ａ）Ｒ^１６、Ｒ^１７及びＲ^１８は相互に独立に炭素数４〜２０の１価の脂環式炭化水素若しくはその誘導体、又は炭素数１〜４の直鎖状若しくは分岐状の飽和炭化水素基を示し、
且つ、Ｒ^１６、Ｒ^１７及びＲ^１８の少なくとも一つが脂環式炭化水素基若しくはその誘導体である。
（Ｂ）Ｒ^１６、Ｒ^１７及びＲ^１８は相互に独立に炭素数４〜２０の１価の脂環式炭化水素若しくはその誘導体、又は炭素数１〜４の直鎖状若しくは分岐状のアルキル基を示し、
且つ、Ｒ^１６、Ｒ^１７及びＲ^１８の何れか２つが相互に結合して、それぞれが結合している炭素原子と共に炭素数４〜２０の２価の脂環式炭化水素基若しくはその誘導体を形成し、
且つ、残りの１つが炭素数１〜４の直鎖状若しくは分岐状のアルキル基又は炭素数４〜２０の１価の脂環式炭化水素基若しくはその誘導体である。］ The present invention is as follows.
1. It contains a polymer having an organic group represented by the following general formula (1) at the end and a repeating unit represented by the following general formula (2), and a radiation-sensitive acid generator. A radiation-sensitive resin composition.

(In formula, R < ¹ >, R < ² > and R < ³ > show a C1-C4 saturated hydrocarbon group mutually independently.)

(In the formula, R ′ represents a hydrogen atom or a methyl group.)
2. A monomer mixture containing a monomer represented by the following general formula (3) and a monomer having an acid-dissociable group is copolymerized using a radical generator represented by the following general formula (4). Then, a copolymer obtained by converting the repeating unit derived from the monomer represented by the general formula (3) into a repeating unit having a phenolic hydroxyl group using a base catalyst, a radiation-sensitive acid generator, A radiation-sensitive resin composition comprising:

(In the formula, R ″ represents a hydrogen atom or a methyl group, and R ⁴ represents a saturated hydrocarbon group having 1 to ⁴ carbon atoms.)

(In the formula, R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a saturated hydrocarbon group having 1 to 4 carbon atoms.)
3. 2. The above 2. wherein the monomer having an acid dissociable group is at least one selected from the compounds represented by the following general formulas (5) and (6). The radiation sensitive resin composition described in 1.

(In the formula, R ¹¹ represents a hydrogen atom or a methyl group, and R ¹² , R ¹³ and R ¹⁴ each independently represent a saturated hydrocarbon group having 1 to 4 carbon atoms.)

[Wherein, R ¹⁵ represents a hydrogen atom or a methyl group. R ¹⁶ , R ¹⁷ and R ¹⁸ satisfy either of the following conditions (A) or (B).
(A) R ¹⁶ , R ¹⁷ and R ¹⁸ are each independently a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched saturated carbonization having 1 to 4 carbon atoms. Indicates a hydrogen group,
At least one of R ¹⁶ , R ¹⁷ and R ¹⁸ is an alicyclic hydrocarbon group or a derivative thereof.
(B) R ¹⁶ , R ¹⁷ and R ¹⁸ are each independently a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms. Indicate
And any two of R ¹⁶ , R ¹⁷ and R ¹⁸ are bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof together with the carbon atoms to which each is bonded. And
The remaining one is a linear or branched alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof. ]

When the radiation-sensitive resin composition of the present invention is used, it is excellent in basic physical properties such as sensitivity as a chemically amplified resist sensitive to far ultraviolet rays such as KrF excimer laser, ArF excimer laser, or F ₂ excimer laser, particularly LER. Characteristics and depth of focus margin are improved. Therefore, it can be used very suitably for the manufacture of integrated circuit elements that are expected to be further miniaturized in the future.

Hereinafter, the present invention will be described in more detail.
[1] Polymer The polymer in the present invention has an organic group represented by the following general formula (1) at the terminal and a repeating unit represented by the following general formula (2) (hereinafter referred to as “repeating unit”). (1) ").

（式中、Ｒ^１、Ｒ^２及びＲ^３は相互に独立に炭素数１〜４の飽和炭化水素基を示す。）

(In formula, R < ¹ >, R < ² > and R < ³ > show a C1-C4 saturated hydrocarbon group mutually independently.)

（式中、Ｒ’は水素原子又はメチル基を示す。）

(In the formula, R ′ represents a hydrogen atom or a methyl group.)

The polymer may have the organic group at at least one terminal. Moreover, you may have this organic group in all the terminals.
Examples of the organic group include t-butyl group, t-pentyl group, t-hexyl group, t-heptyl group, t-octyl and the like. Moreover, the terminal may be represented by the following general formula (1 ′).

（式中、Ｒ^１、Ｒ^２及びＲ^３は相互に独立に炭素数１〜４の飽和炭化水素基を示す。）

(In formula, R < ¹ >, R < ² > and R < ³ > show a C1-C4 saturated hydrocarbon group mutually independently.)

When the terminal is an organic group represented by the general formula (1 ′), the solubility of the resin during development can be improved. Examples of the organic group represented by the general formula (1 ′) include a t-butoxy group, a t-pentyloxy group, a t-hexyloxy group, a t-heptyloxy group, and a t-octyloxy group. Can be mentioned.
Of these organic groups, a t-butyl group and a t-butoxy group are preferable.

  In the radiation-sensitive resin composition of the present invention, the organic group is introduced at the terminal of the polymer, so that the solubility of the resin during development is improved. As a result, the LER characteristics and the depth of focus allowance Is estimated to improve.

  Examples of the repeating unit (1) include o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, p-isopropenylphenol and the like. Among these, p-hydroxystyrene is preferable.

  The repeating unit (1) is derived from, for example, a monomer represented by the following general formula (3) (hereinafter referred to as “monomer (a)”).

（式中、Ｒ"は水素原子又はメチル基を示し、Ｒ^４は炭素数１〜４の飽和炭化水素基を示す。）

(In the formula, R ″ represents a hydrogen atom or a methyl group, and R ⁴ represents a saturated hydrocarbon group having 1 to ⁴ carbon atoms.)

Examples of the monomer (a) include o-acetoxystyrene, m-acetoxystyrene, p-acetoxystyrene, o-propionyloxystyrene, m-propionyloxystyrene, p-propionyloxystyrene, and o-butyryloxy. Examples thereof include styrene, m-butyryloxystyrene, p-butyryloxystyrene, and the like. Among these, those in which [—OC (O) R ⁴ group] in the formula is bonded to the p-position are preferable, and p-acetoxystyrene is particularly preferable.
In addition, these monomers (a) can be used individually or in mixture of 2 or more types.

Moreover, the polymer in this invention may contain other repeating units other than the said repeating unit (1).
Examples of the other repeating unit include a unit in which a polymerizable unsaturated bond in a monomer having an acid dissociable group (hereinafter referred to as “monomer (b)”) is cleaved (hereinafter referred to as “repeating unit (2)”. )), A unit (hereinafter referred to as “repeat unit (3)”) in which a polymerizable unsaturated bond in a monomer other than the monomer (b) (hereinafter referred to as “monomer (c)”) is cleaved. Can be mentioned.
In addition, it is preferable that the said polymer contains the repeating unit (2) which consists of a unit which the polymerizable unsaturated bond in the monomer (b) which has an acid dissociable group was cleaved.

  Examples of the monomer (b) include compounds having an acid dissociable group represented by the following general formula (5) and the following general formula (6).

（式中、Ｒ^１１は水素原子又はメチル基、Ｒ^１２、Ｒ^１３及びＲ^１４は相互に独立に炭素数１〜４の飽和炭化水素基を示す。）

(In the formula, R ¹¹ represents a hydrogen atom or a methyl group, and R ¹² , R ¹³ and R ¹⁴ each independently represent a saturated hydrocarbon group having 1 to 4 carbon atoms.)

［式中、Ｒ^１５は水素原子又はメチル基である。また、Ｒ^１６、Ｒ^１７及びＲ^１８は、以下の（Ａ）又は（Ｂ）のいずれかの条件を満たす。
（Ａ）Ｒ^１６、Ｒ^１７及びＲ^１８は相互に独立に炭素数４〜２０の１価の脂環式炭化水素若しくはその誘導体、又は炭素数１〜４の直鎖状若しくは分岐状のアルキル基を示し、
且つ、Ｒ^１６、Ｒ^１７及びＲ^１８の少なくとも一つが脂環式炭化水素基若しくはその誘導体である。
（Ｂ）Ｒ^１６、Ｒ^１７及びＲ^１８は相互に独立に炭素数４〜２０の１価の脂環式炭化水素若しくはその誘導体、又は炭素数１〜４の直鎖状若しくは分岐状のアルキル基を示し、
且つ、Ｒ^１６、Ｒ^１７及びＲ^１８の何れか２つが相互に結合して、それぞれが結合している炭素原子と共に炭素数４〜２０の２価の脂環式炭化水素基若しくはその誘導体を形成し、
且つ、残りの１つが炭素数１〜４の直鎖状若しくは分岐状のアルキル基又は炭素数４〜２０の１価の脂環式炭化水素基若しくはその誘導体である。］

[Wherein, R ¹⁵ represents a hydrogen atom or a methyl group. R ¹⁶ , R ¹⁷ and R ¹⁸ satisfy either of the following conditions (A) or (B).
(A) R ¹⁶ , R ¹⁷ and R ¹⁸ are each independently a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms. Indicate
At least one of R ¹⁶ , R ¹⁷ and R ¹⁸ is an alicyclic hydrocarbon group or a derivative thereof.
(B) R ¹⁶ , R ¹⁷ and R ¹⁸ are each independently a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms. Indicate
And any two of R ¹⁶ , R ¹⁷ and R ¹⁸ are bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof together with the carbon atoms to which each is bonded. And
The remaining one is a linear or branched alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof. ]

  Examples of the monomer represented by the general formula (5) include pt-butoxystyrene, pt-butoxy-α-methylstyrene, p- (2-ethyl-2-propoxy) styrene, p. -(2-Ethyl-2-propoxy) -α-methylstyrene, mt-butoxystyrene and the like can be mentioned.

In the general formula (6), R ¹⁶ , R ¹⁷ , and R ¹⁸ satisfying the condition (A) or (B) include, for example, norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclobutane, cyclo A group consisting of an alicyclic ring derived from cycloalkanes such as pentane, cyclohexane, cycloheptane, cyclooctane, etc .; a group consisting of these alicyclic rings, for example, a methyl group, an ethyl group, an n-propyl group, 1 or more types of linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms such as i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, etc. Examples include groups substituted with one or more. Among these alicyclic hydrocarbon groups, the group consisting of an alicyclic ring derived from norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclopentane or cyclohexane, or a group consisting of these alicyclic rings is described above. A group substituted with an alkyl group is preferred.

  Examples of the alicyclic hydrocarbon group derivatives include hydroxyl group; carboxyl group; oxo group (that is, ═O group); hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1- Hydroxypropyl groups having 1 to 4 carbon atoms such as hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group and 4-hydroxybutyl group An alkoxyl group having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, a 2-methylpropoxy group, a 1-methylpropoxy group and a t-butoxy group; Group: C2-C5 such as cyanomethyl group, 2-cyanoethyl group, 3-cyanopropyl group, 4-cyanobutyl group, etc. A substituent such as Anoarukiru group can include one or more or one or more having groups. Of these substituents, a hydroxyl group, a carboxyl group, a hydroxymethyl group, a cyano group, a cyanomethyl group, and the like are preferable.

Moreover, as a C1-C4 linear or branched alkyl group of R <^16> , R < ¹⁷ >, R < ¹⁸ >, a methyl group, an ethyl group, n-propyl group, i-propyl group, n-butyl is mentioned, for example. Group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like. Of these alkyl groups, a methyl group and an ethyl group are preferable.

  Examples of the monomer represented by the general formula (6) include t-butyl (meth) acrylate, cyclopentyl (meth) acrylate, 1-methylcyclopentyl (meth) acrylate, 1-ethylcyclopentyl (meth) acrylate, Cyclohexyl (meth) acrylate, 1-methylcyclohexyl (meth) acrylate, 1-ethylcyclohexyl (meth) acrylate, benzyl (meth) acrylate, norbornyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate , Dicyclopentenyl (meth) acrylate, adamantane-1-yl (meth) acrylate, 2-methyladamantan-2-yl (meth) acrylate, 2-ethyladamantan-2-yl (meth) acrylate May be mentioned tetrahydrofuranyl (meth) acrylate, tetrahydropyranyl (meth) acrylate of a (meth) acrylic acid ester monomer and the like.

As the monomer (b), (meth) acrylic acid ester monomers such as i-propyl (meth) acrylate and sec-butyl (meth) acrylate; t-butoxycarbonyloxystyrene, pt And vinyl aromatic monomers such as -butoxycarbonylmethyloxystyrene, p- (2-t-butoxycarbonylethyloxy) styrene, p-tetrahydrofuranyloxystyrene, p-tetrahydropyranyloxystyrene, and the like. .
Among these monomers (b), at least one selected from the compounds represented by the general formulas (5) and (6) is preferable. In particular, pt-butoxystyrene and t-butyl (meth) acrylate are preferable.
In addition, these monomers (b) can be used individually or in mixture of 2 or more types.

  Examples of the monomer (c) include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-hydroxy-α-methylstyrene, m-hydroxy-α. -Vinyl aromatic compounds such as methylstyrene, p-hydroxy-α-methylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl ( (Meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, n-pentyl (meth) acrylate, neopentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- Mud hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, adamantylmethyl (meth) acrylate, phenyl (meth) acrylate, phenethyl (meth) acrylate,

（式中、ａは１〜６の整数である。）、 Monomer represented by the following formula (7)

(Wherein, a is an integer of 1 to 6),

（式中、ｂは１〜６の整数である。）、 Monomer represented by the following formula (8)

(Wherein b is an integer of 1 to 6),

（式中、各ｃはそれぞれ１〜６の整数である。）
等の他の（メタ）アクリル酸エステル類； Monomer represented by the following formula (9)

(In the formula, each c is an integer of 1 to 6)
Other (meth) acrylic acid esters, etc .;

（式中、Ｒ^１９は水素原子又はメチル基を表し、Ｒ^２０及びＲ^２１は相互に独立に水素原子又は炭素数１〜４の飽和炭化水素基を表す。）； Unsaturated amide compound represented by the following general formula (10)

(In the formula, R ¹⁹ represents a hydrogen atom or a methyl group, and R ²⁰ and R ²¹ each independently represent a hydrogen atom or a saturated hydrocarbon group having 1 to 4 carbon atoms);

Unsaturated carboxylic acids such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid and cinnamic acid; unsaturated polycarboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; (meth) acrylic acid 2 -Carboxyalkyl esters of unsaturated carboxylic acids such as carboxyethyl, 2-carboxypropyl (meth) acrylate, 3-carboxypropyl (meth) acrylate; (meth) acrylonitrile, α-chloroacrylonitrile, crotonnitrile, maleinnitrile Unsaturated nitrile compounds such as fumaronitrile; unsaturated imide compounds such as maleimide, N-phenylmaleimide, N-cyclohexylmaleimide; N-vinyl-ε-caprolactam, N-vinylpyrrolidone, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 2-vinyli Examples of the monomer include other nitrogen-containing vinyl compounds such as midazole and 4-vinylimidazole.
Among these monomers (c), styrene, α-methylstyrene, a monomer represented by the above formula (7), and an unsaturated amide compound represented by the above general formula (10) are preferable.
In addition, these monomers (c) can be used individually or in mixture of 2 or more types.
The other repeating units may be present alone or in combination of two or more.

  The polymer in the present invention is an alkali-insoluble or alkali-insoluble polymer having a property of becoming alkali-soluble by the action of an acid. The term “alkali insoluble or alkali insoluble” as used herein refers to an alkali development condition employed when a resist pattern is formed from a resist film formed using a radiation-sensitive resin composition containing a polymer. When a film using only the above polymer is developed instead of the resist film, it means a property that 50% or more of the initial film thickness of the film remains after development.

The content of the repeating unit (1) in the polymer is usually 50 to 90 mol%, preferably 55 to 90 mol%, more preferably 60 to 90 mol%, still more preferably 60, based on all repeating units. -85 mol%. When the content rate of this repeating unit (1) is less than 50 mol%, there exists a tendency for the adhesiveness of the resist pattern to the board | substrate to fall. On the other hand, when it exceeds 90 mol%, the resolution tends to decrease.
The content of the repeating unit (2) in the polymer is preferably 50 mol% or less, more preferably 5 to 45 mol%, still more preferably 10 to 40 mol%, particularly preferably based on all repeating units. Is from 10 to 35 mol%. When the content rate of this repeating unit (2) exceeds 50 mol%, there exists a tendency for the adhesiveness to the board | substrate of a resist pattern to fall.
Furthermore, the content of the repeating unit (3) in the polymer is preferably 40 mol% or less, more preferably 30 mol% or less, still more preferably 1 to 25 mol%, particularly preferably based on all repeating units. 5 to 20 mol%. When the content rate of this repeating unit (3) exceeds 40 mol%, the resolution tends to decrease.

The polystyrene-reduced weight molecular weight (hereinafter referred to as “Mw”) of the above polymer measured by gel permeation chromatography (GPC) is usually 1,000 to 150,000, preferably 3,000 to 100,000. is there.
The ratio (Mw / Mn) of the polymer Mw and the polystyrene-equivalent molecular weight (hereinafter referred to as “Mn”) measured by gel permeation chromatography (GPC) is usually 1 to 10, preferably 1. ~ 5.
In the radiation-sensitive resin composition of the present invention, the polymers can be used alone or in admixture of two or more.

The production method of the polymer is not particularly limited. For example, [1] a radical generator such as ditertiary butyl peroxide which gives an organic group represented by the general formula (1) and acetoxy which gives a repeating unit (1) After copolymerization with a monomer such as styrene, optionally together with a monomer that gives the above other repeating units (2) and / or (3), an alkoxy such as an acetoxy group in the resulting copolymer A method of selectively hydrolyzing a carbonyl group, [2] a part of hydrogen atoms of the phenolic hydroxyl group in the precursor resin containing a phenolic hydroxyl group is substituted with -C (R ^x ) ₃ groups (where each R ^x Represents a saturated hydrocarbon group having 1 to 4 carbon atoms independently of each other.] [3] Ditertiary butyl which gives an organic group represented by the above general formula (1) Peroxid And a monomer that gives a repeating unit (1), optionally together with a monomer that gives another repeating unit (2) and / or (3). be able to.

  In addition, the monomer mixture containing the monomer (a) represented by the general formula (3) and the monomer (b) having an acid dissociable group is converted into a radical represented by the following general formula (4). After copolymerization using the generator, a method of converting the repeating unit derived from the monomer represented by the general formula (3) into a repeating unit having a phenolic hydroxyl group using a base catalyst is preferable.

（式中、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、Ｒ^９及びＲ^１０は相互に独立に炭素数１〜４の飽和炭化水素基を示す。）

(In the formula, R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a saturated hydrocarbon group having 1 to 4 carbon atoms.)

Examples of the radical generator represented by the general formula (4) include ditertiary butyl peroxide, ditertiary pentyl peroxide, ditertiary hexyl peroxide, ditertiary heptyl peroxide, ditertiary octyl peroxide and the like. be able to. Among these, ditertiary butyl peroxide is preferable.
The compounding amount of the radical generator is usually 0.5 to 20 parts by mass, preferably 1 to 15 parts by mass, and more preferably 2 to 10 parts by mass with respect to 100 parts by mass of the monomer mixture.

  Examples of the base catalyst include triethylamine, sodium hydroxide, sodium methoxide, sodium ethoxide and the like. Of these, triethylamine is preferred.

  Examples of the repeating unit having a phenolic hydroxyl group include a repeating unit represented by the above formula (2), a unit in which a polymerizable unsaturated bond of hydroxy-α-methylstyrene is cleaved, and the like.

[2] Radiation-sensitive acid generator The radiation-sensitive acid generator in the present invention (hereinafter also simply referred to as “acid generator”) is an acid produced by exposure to radiation such as ultraviolet rays, far ultraviolet rays, electron beams, and X-rays. It is a substance that generates This acid generator dissociates the acid dissociable groups present in the polymer by the action of the acid generated by exposure, and as a result, the exposed portion of the resist film becomes readily soluble in an alkali developer, and a positive resist pattern. It has the effect | action which forms.

Examples of the acid generator include N-sulfonyloxyimide compounds, diphenyliodonium salt compounds, onium salt compounds such as iodonium salts and sulfonium salts, organic halogen compounds, sulfone compounds such as disulfones and disulfonyldiazomethanes, and the like. be able to. Among these, N-sulfonyloxyimide compounds, diphenyliodonium salt compounds, onium salt compounds, and disulfonyldiazomethanes are preferable, and N-sulfonyloxyimide compounds and diphenyliodonium salt compounds are particularly preferable.
In addition, the diphenyliodonium salt compound has a higher radiation transmittance than the triphenylsulfonium salt, bis (t-butyl) iodonium salt, and the like, and pattern shape deterioration and pattern line width when defocused. In this case, when this diphenyliodoiodonium salt compound is used in combination with an N-sulfonyloxyimide compound having a strong dissolution inhibiting effect, a larger depth of focus margin is exhibited. Can be achieved.

  As the N-sulfonyloxyimide compound, for example, a compound represented by the following general formula (11) is preferable.

（式中、Ｒ^２２は２価の有機基を示し、Ｒ^２３は１価の有機基を示す。）

(In the formula, R ²² represents a divalent organic group, and R ²³ represents a monovalent organic group.)

In the general formula (11), examples of the divalent organic group represented by R ²² include a methylene group, a linear or branched alkylene group having 2 to 20 carbon atoms, an aralkylene group having 2 to 20 carbon atoms, and difluoromethylene. A divalent group having a group, a linear or branched perfluoroalkylene group having 2 to 20 carbon atoms, a cyclohexylene group, a phenylene group or a norbornane skeleton, or an aryl group or carbon having 6 or more carbon atoms. Examples thereof include a group substituted with an alkoxyl group having a number of 1 or more.

Examples of the monovalent organic group for R ²³ include a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched perfluoroalkyl group having 1 to 10 carbon atoms, and carbon. Examples include a perfluorocycloalkyl group having 3 to 10 carbon atoms, a monovalent hydrocarbon group having 7 to 15 carbon atoms having a bicyclo ring, an aryl group having 6 to 12 carbon atoms, and the like, and a hydrocarbon having the bicyclo ring The group and the aryl group may each be substituted with a halogen atom or an oxo group.

Specific examples of the N-sulfonyloxyimide compound represented by the general formula (11) include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboxy. Imido, N- (nonafluoro-n-butanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (benzenesulfonyloxy) bicyclo [2.2.1] Examples thereof include hept-5-ene-2,3-dicarboximide, N- (p-toluenesulfonyloxy) succinimide, N- (10-camphorsulfonyloxy) succinimide and the like.
Of these, N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide is preferred.

  As said diphenyl iodonium salt compound, the compound represented, for example by following General formula (12) is preferable.

（式中、Ｘ⁻は１価のアニオンを表す。）

(Wherein, X ^- represents a monovalent anion.)

In the general formula (12), as the monovalent anion of X ⁻ , for example, MX _i (where M represents a boron atom, phosphorus atom, arsenic atom or antimony atom, X represents a halogen atom, and i represents And an anion of 4 to 6.), a halogen anion, a sulfonic acid anion having 1 to 20 carbon atoms, a carboxylic acid anion having 1 to 20 carbon atoms, and the like. It may be substituted with a halogen atom or an oxo group.

As the diphenyliodonium salt compound represented by the general formula (12), a compound in which X ⁻ is the sulfonate anion is preferable, and specific examples thereof include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butane. Examples include sulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium p-toluenesulfonate, diphenyliodoniumbenzenesulfonate, diphenyliodonium10-camphorsulfonate, diphenyliodonium p-trifluoromethylbenzenesulfonate, diphenyliodonium perfluorobenzenesulfonate, and the like. be able to.
Of these, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium 10-camphorsulfonate, and the like are preferable.

  Examples of the onium salt compound include bis (pt-butylphenyl) iodonium trifluoromethanesulfonate, bis (pt-butylphenyl) iodonium nonafluoro-n-butanesulfonate, and bis (pt-butylphenyl). Iodonium perfluoro-n-octane sulfonate, bis (pt-butylphenyl) iodonium p-toluenesulfonate, bis (pt-butylphenyl) iodonium 10-camphorsulfonate, bis (pt-butylphenyl) iodonium 4 -Trifluoromethylbenzenesulfonate, bis (pt-butylphenyl) iodonium perfluorobenzenesulfonate, bis (p-fluorophenyl) iodonium trifluoromethanesulfonate, bis (p-fluoro Enyl) iodonium nonafluoro-n-butanesulfonate, bis (p-fluorophenyl) iodonium perfluoro-n-octanesulfonate, bis (p-fluorophenyl) iodonium 10-camphorsulfonate, (p-fluorophenyl) (phenyl) iodonium Trifluoromethanesulfonate, (p-fluorophenyl) (phenyl) iodonium nonafluoro-n-butanesulfonate, (p-fluorophenyl) (phenyl) iodonium perfluoro-n-octanesulfonate, (p-fluorophenyl) (phenyl) iodonium 10-camphor sulfonate,

  Triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfoniumbenzenesulfonate, triphenylsulfonium 10-camphorsulfonate , Triphenylsulfonium p-trifluoromethylbenzenesulfonate, triphenylsulfonium perfluorobenzenesulfonate, tris (p-methoxyphenyl) sulfonium trifluoromethanesulfonate, tris (p-methoxyphenyl) sulfonium nonafluoro-n-butanesulfonate, tris ( p-methoxyphenyl) sulfonium perfluoro n-octanesulfonate, tris (p-methoxyphenyl) sulfonium p-toluenesulfonate, tris (p-methoxyphenyl) sulfoniumbenzenesulfonate, tris (p-methoxyphenyl) sulfonium 10-camphorsulfonate, tris (p-methoxyphenyl) sulfonium p-trifluoromethylbenzenesulfonate, tris (p-methoxyphenyl) sulfonium perfluorobenzenesulfonate,

  Tris (p-fluorophenyl) sulfonium trifluoromethanesulfonate, tris (p-fluorophenyl) sulfonium p-toluenesulfonate, (p-hydroxyphenyl) diphenylsulfonium trifluoromethanesulfonate, (p-hydroxyphenyl) diphenylsulfonium p-toluenesulfonate, (P-Fluorophenyl) diphenylsulfonium trifluoromethanesulfonate, (p-fluorophenyl) diphenylsulfonium p-toluenesulfonate, and the like.

Examples of the disulfonyldiazomethanes include bis (cyclohexylsulfonyl) diazomethane, bis (3,3-dimethyl-1,5-dioxaspiro [5.5] dodecane-8-sulfonyl) diazomethane, and bis (t-butylsulfonyl). And diazomethane.
In addition, these acid generators can be used individually or in mixture of 2 or more types.

  Content of the acid generator in the radiation sensitive resin composition of this invention is 0.1-20 mass parts normally with respect to 100 mass parts of said polymers, Preferably it is 0.1-15 mass parts. Preferably it is 0.1-10 mass parts. By setting it as such content, the sensitivity and developability as a resist can be sufficiently ensured. On the other hand, when the content of the acid generator is less than 0.1 parts by mass, sensitivity and developability tend to decrease. It tends to be difficult to obtain a pattern.

[3] Additives The radiation-sensitive resin composition of the present invention may contain various additives such as an acid diffusion controller, a surfactant, and a sensitizer as necessary.
Among these, it is preferable to mix an acid diffusion control agent having an action of controlling an undesired chemical reaction in a non-exposed region by controlling a diffusion phenomenon in the resist film of an acid generated from an acid generator by exposure. . By using such an acid diffusion control agent, the storage stability of the composition is improved, the resolution as a resist is improved, and the holding time (PED) from exposure to heat treatment after exposure is increased. Changes in the line width of the resist pattern due to fluctuations can be suppressed, and the process stability is extremely excellent.

The acid diffusion controller is preferably a nitrogen-containing organic compound whose basicity does not change by exposure or heat treatment during the resist pattern formation step.
As such a nitrogen-containing organic compound, for example, a compound represented by the following general formula (13) (hereinafter referred to as “nitrogen-containing compound (α)”), a compound represented by the following general formula (14) ( Hereinafter, referred to as “nitrogen-containing compound (β)”), diamino compound having two nitrogen atoms in the same molecule (hereinafter referred to as “nitrogen-containing compound (γ)”), diamino polymer having three or more nitrogen atoms (Hereinafter referred to as “nitrogen-containing compound (δ)”), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

（式中、Ｒ^２４及びＲ^２５は相互に独立に１価の有機基を表すか、或いはＲ^２４及びＲ^２５が相互に結合して式中の窒素原子と共に環を形成している。）

(In the formula, R ²⁴ and R ²⁵ each independently represent a monovalent organic group, or R ²⁴ and R ²⁵ are bonded to each other to form a ring together with the nitrogen atom in the formula.)

（式中、Ｒ^２６、Ｒ^２７及びＲ^２８は相互に独立に水素原子、炭素数１〜１０の直鎖状若しくは分岐状のアルキル基、炭素数３〜１０のシクロアルキル基、炭素数６〜２０のアリール基又は炭素数７〜１８のアラルキル基を示し、これらのアルキル基、アリール基及びアラルキル基はそれぞれヒドロキシ基等の官能基で置換されていてもよい。）

(In the formula, R ²⁶ , R ²⁷ and R ²⁸ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or 6 to 6 carbon atoms. 20 aryl groups or aralkyl groups having 7 to 18 carbon atoms, and these alkyl groups, aryl groups and aralkyl groups may each be substituted with a functional group such as a hydroxy group.)

In the general formula (13), examples of the monovalent organic group represented by R ²⁴ and R ²⁵ include a linear or branched alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and carbon. An aryl group having 6 to 20 carbon atoms or an aralkyl group having 7 to 18 carbon atoms is shown, and these alkyl group, aryl group and aralkyl group may each be substituted with a functional group such as a hydroxy group.
Examples of the ring formed by combining R ²⁴ and R ²⁵ together with the nitrogen atom in the formula include a 5- to 6-membered ring, and these rings may further include a nitrogen atom, an oxygen atom, etc. One or more additional hetero atoms can also be contained.

  Examples of the nitrogen-containing compound (α) include N- (t-butoxycarbonyl) piperidine, N- (t-butoxycarbonyl) imidazole, N- (t-butoxycarbonyl) benzimidazole, N- (t-butoxycarbonyl). ) -2-phenylbenzimidazole, N- (t-butoxycarbonyl) di-n-octylamine, N- (t-butoxycarbonyl) diethanolamine, N- (t-butoxycarbonyl) dicyclohexylamine, N- (t-butoxy And carbonyl) diphenylamine.

  Examples of the nitrogen-containing compound (β) include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; di-n-butylamine, di-n. -Dialkylamines such as pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine; triethylamine, tri-n-propylamine , Tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, etc. Amines; aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3 Methylaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, aromatic amines such as 1-naphthylamine; can be mentioned monoethanolamine, diethanolamine, alkanolamines such as triethanolamine and the like.

Examples of the nitrogen-containing compound (γ) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′tetrakis (2-hydroxypropyl) ethylenediamine, tetramethylenediamine, Hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 2,2′-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4-aminophenyl) -2- ( 4-hydroxyphenyl) propane, 1,4-bis [1- (4-aminophenyl) -1-methylethyl] Benzene, 1,3-bis can be mentioned [1- (4-aminophenyl) -1-methylethyl] benzene, and the like.
Examples of the nitrogen-containing compound (δ) include polyethyleneimine, polyallylamine, N- (2-dimethylaminoethyl) acrylamide polymer, and the like.

Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone and the like. Can be mentioned.
Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tributylthiourea and the like. be able to.
Examples of the nitrogen-containing heterocyclic compound include imidazoles such as imidazole, benzimidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, and 2-phenylbenzimidazole; pyridine, 2-methylpyridine, 4-methyl Such as pyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 8-oxyquinoline, acridine, etc. In addition to pyridines, pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, morpholine, 4-methylmorpholine, piperazine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane, etc. To list It can be.

Of these nitrogen-containing organic compounds, nitrogen-containing compounds (α), nitrogen-containing heterocyclic compounds and the like are preferable, and in particular, N- (t-butoxycarbonyl) -2-phenylbenzimidazole, N- (t-butoxycarbonyl) Dicyclohexylamine, imidazoles and the like are preferable.
In the radiation-sensitive resin composition of the present invention, the acid diffusion controller can be used alone or in admixture of two or more.

  The compounding amount of the acid diffusion controller is usually 15 parts by mass or less, preferably 0.001 to 10 parts by mass, and more preferably 0.005 to 5 parts by mass with respect to 100 parts by mass of the polymer. In this case, when the compounding amount of the acid diffusion controller exceeds 15 parts by mass, the sensitivity as a resist and the developability of the exposed part tend to be lowered. In addition, if the compounding quantity of an acid diffusion control agent is less than 0.001 mass part, there exists a possibility that the pattern shape and dimension fidelity as a resist may fall depending on process conditions.

The surfactant is a component that exhibits an effect of improving coatability, striation, developability as a resist, and the like.
Examples of such surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene-n-octylphenol ether, polyoxyethylene-n-nonylphenol ether, polyethylene glycol dilaurate. And polyethylene glycol distearate. Further, F-top EF301, EF303, EF352 (above, manufactured by Tochem Products); Megafax F171, F173 (above, manufactured by Dainippon Ink and Chemicals); Florard FC430, FC431 (above, Manufactured by Sumitomo 3M Limited), Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (above, manufactured by Asahi Glass Co., Ltd.); KP341 (Shin-Etsu Chemical Co., Ltd.) Product), Polyflow No. 75, no. 95 (above, manufactured by Kyoeisha Chemical Co., Ltd.).
It is preferable that the compounding quantity of surfactant is 2 mass parts or less with respect to 100 mass parts of said polymers.

Examples of the sensitizer include benzophenones, rose bengals, and anthracene.
The blending amount of the sensitizer is preferably 50 parts by mass or less with respect to 100 parts by mass of the polymer.
In addition, by blending dyes and / or pigments, the latent image of the exposed area can be visualized, and the influence of halation during exposure can be reduced. By blending an adhesion aid, adhesion to the substrate is further improved. can do.
Furthermore, as additives other than those described above, an antihalation agent such as 4-hydroxy-4′-methylchalcone, a shape improver, a storage stabilizer, an antifoaming agent, and the like can be blended.

[4] Composition Solution The radiation-sensitive resin composition of the present invention usually has a total solid concentration of 0.1 to 50% by mass, preferably 1 to 40% by mass, when used. Further, after being uniformly dissolved in a solvent, it is prepared as a composition solution by, for example, filtering with a filter having a pore diameter of about 0.2 μm.
Examples of the solvent include ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, and ethylene glycol mono-n-butyl ether acetate; propylene glycol Propylene glycol monoalkyl ethers such as monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether; propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl Ether, propylene glycol di-n-butyl ether Propylene glycol dialkyl ethers such as Le; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono -n- propyl ether acetate, propylene glycol monoalkyl ether acetates such as propylene glycol monobutyl -n- butyl ether acetate;

Lactic acid esters such as methyl lactate, ethyl lactate, n-propyl lactate, i-propyl lactate; formate esters such as n-amyl formate and i-amyl formate; ethyl acetate, n-propyl acetate, i-acetate Acetic esters such as propyl, n-butyl acetate, i-butyl acetate, n-amyl acetate, i-amyl acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate; i-propyl propionate, propionate Propionic acid esters such as n-butyl acid, i-butyl propionate, 3-methyl-3-methoxybutyl propionate; ethyl hydroxyacetate, ethyl 2-hydroxy-2-methylpropionate, 2-hydroxy-3- Methyl methylbutyrate, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, 3-methoxy Other esters such as ethyl lopionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, ethyl acetoacetate, methyl pyruvate, ethyl pyruvate Aromatic hydrocarbons such as toluene and xylene; ketones such as methyl ethyl ketone, 2-pentanone, 2-hexanone, 2-heptanone, 3-heptanone, 4-heptanone and cyclohexanone; N-methylformamide, N, N-dimethyl Examples include amides such as formamide, N-methylacetamide, N, N-dimethylacetamide, and N-methylpyrrolidone; lactones such as γ-butyrolacun.
These solvents can be used alone or in admixture of two or more.

[5] Method for forming resist pattern When forming a resist pattern from the radiation-sensitive resin composition of the present invention, the composition solution prepared as described above is spin-coated, cast-coated, roll-coated, etc. With a suitable coating means, for example, a resist film is formed by coating on a substrate such as a silicon wafer or a wafer coated with aluminum, and in some cases, a heat treatment (hereinafter referred to as 70 ° C. to 160 ° C.) is performed. , “PB”), and then exposure is performed through a predetermined mask pattern.
The radiation used for the exposure may be, for example, far ultraviolet rays such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), or the like, depending on the type of acid generator. Although charged particle beams such as X-rays such as tron radiation and electron beams can be appropriately selected and used, far ultraviolet rays such as KrF excimer laser (wavelength 248 nm) are preferred.
Moreover, exposure conditions, such as exposure amount, are suitably selected according to the compounding composition of the radiation sensitive resin composition used, the kind of each additive, etc.

In the present invention, in order to stably form a high-precision fine pattern, it is preferable to perform a heat treatment (hereinafter referred to as “PEB”) for 30 seconds or longer after exposure, preferably at a temperature of about 70 to 160 ° C. . In this case, if the temperature of the PEB is less than 70 ° C., there is a possibility that the variation in sensitivity depending on the type of the substrate is spread.
Thereafter, using an alkali developer, development is usually performed at 10 to 50 ° C. for 10 to 200 seconds, preferably at 15 to 30 ° C. for 15 to 100 seconds, particularly preferably at 20 to 25 ° C. for 15 to 90 seconds. The resist pattern is formed.
As the alkali developer, for example, an alkaline compound such as tetraalkylammonium hydroxide is usually 1 to 10% by mass, preferably 1 to 5% by mass, particularly preferably 1 to 3% by mass. A dissolved alkaline aqueous solution is used.
Further, for example, a water-soluble organic solvent such as methanol or ethanol, or a surfactant can be appropriately added to the developer composed of the alkaline aqueous solution.
In forming the resist pattern, a protective film can be provided on the resist film in order to prevent the influence of basic impurities contained in the environmental atmosphere.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Here, the part is based on mass unless otherwise specified.

Synthesis Example 1 [Production of copolymer (A-1)]
After dissolving 101 g of p-acetoxystyrene, 5 g of styrene, 42 g of pt-butoxystyrene and 9 g of ditertiary butyl peroxide in 160 g of propylene glycol monomethyl ether, the reaction temperature is maintained at 70 ° C. under a nitrogen atmosphere. Polymerized for hours. After the polymerization, the reaction solution was dropped into a large amount of hexane to coagulate and purify the resulting polymer. Next, 150 g of propylene glycol monomethyl ether was added to the purified polymer again, and then 300 g of methanol, 80 g of triethylamine and 15 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained copolymer was dissolved in acetone, then dropped into a large amount of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. Dried overnight.
The obtained copolymer had Mw of 15,000 and Mw / Mn of 1.8. As a result of ¹³ C-NMR analysis, copolymerization moles of p-hydroxystyrene, styrene and pt-butoxystyrene were obtained. The ratio was 72: 5: 23. This copolymer is referred to as “copolymer (A-1)”.

  The measurement of Mw and Mn of the copolymer (A-1) and the copolymers (A-2), (A-3) and (a-1) described later were performed by Tosoh Co., Ltd. GPC columns (2 G2000HXL, G3000HXL and G4000HXL) were measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under the analysis conditions of a flow rate of 1.0 ml / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C.

Synthesis Example 2 [Production of copolymer (A-2)]
100 g of p-acetoxystyrene, 25 g of t-butyl acrylate, 18 g of styrene, and 9 g of ditertiary butyl peroxide are dissolved in 230 g of propylene glycol monomethyl ether, and polymerized for 16 hours while maintaining the reaction temperature at 70 ° C. in a nitrogen atmosphere. It was. After the polymerization, the reaction solution was dropped into a large amount of hexane to coagulate and purify the resulting polymer. Next, 150 g of propylene glycol monomethyl ether was added to the purified polymer again, and then 300 g of methanol, 80 g of triethylamine and 15 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained copolymer was dissolved in acetone, then dropped into a large amount of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. Dried overnight.
The obtained copolymer has Mw of 11,500 and Mw / Mn of 1.6. As a result of ¹³ C-NMR analysis, copolymerization molar ratio of p-hydroxystyrene, t-butyl acrylate and styrene is obtained. Was 61:19:20. This copolymer is referred to as “copolymer (A-2)”.

Synthesis Example 3 [Production of Copolymer (A-3)]
114 g of p-acetoxystyrene, 19 g of tert-butyl acrylate, 32 g of pt-butoxystyrene and 9 g of ditertiary butyl peroxide were dissolved in 230 g of propylene glycol monomethyl ether, and the reaction temperature was maintained at 70 ° C. in a nitrogen atmosphere. For 16 hours. After the polymerization, the reaction solution was dropped into a large amount of hexane to coagulate and purify the resulting polymer. Next, 150 g of propylene glycol monomethyl ether was added to the purified polymer again, and then 300 g of methanol, 80 g of triethylamine and 15 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the resulting copolymer was dissolved in acetone, then dropped into a large amount of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. Dried overnight.
The obtained copolymer has Mw of 11,500 and Mw / Mn of 1.6. As a result of ¹³ C-NMR analysis, p-hydroxystyrene, t-butyl acrylate, pt-butoxystyrene, The copolymer molar ratio was 65:15:20. This copolymer is referred to as “copolymer (A-3)”.

Comparative Synthesis Example 1 [Production of Copolymer (a-1)]
101 g of p-acetoxystyrene, 5 g of styrene, 42 g of p-t-butoxystyrene, 6 g of azobisisobutyronitrile (AIBN) and 1 g of t-dodecyl mercaptan were dissolved in 160 g of propylene glycol monomethyl ether, and then reacted in a nitrogen atmosphere. The temperature was maintained at 70 ° C. and polymerization was performed for 16 hours. After the polymerization, the reaction solution was dropped into a large amount of hexane to coagulate and purify the resulting polymer. Next, 150 g of propylene glycol monomethyl ether was added to the purified polymer again, and then 300 g of methanol, 80 g of triethylamine and 15 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained copolymer was dissolved in acetone, then dropped into a large amount of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. Dried overnight.
The obtained copolymer had Mw of 16,000 and Mw / Mn of 1.7. As a result of ¹³ C-NMR analysis, copolymerization moles of p-hydroxystyrene, styrene, and pt-butoxystyrene were obtained. The ratio was 72: 5: 23. This copolymer is referred to as “copolymer (a-1)”.

Examples 1 to 5 and Comparative Example 1
After mixing each component shown in Table 1 ("part" is a mass reference | standard) and making it a uniform solution, it filtered with the membrane filter with the hole diameter of 0.2 micrometer, and prepared the radiation sensitive resin composition solution. Then, after spin-coating DUV42 (composition for antireflection film) manufactured by Brewer Science Co., Ltd. so as to have a film thickness of 600 Å, each composition solution was spin-coated on a silicon wafer baked at 205 ° C. for 60 seconds. PB was performed under the conditions shown in Table 2 to form a resist film having a thickness of 0.4 μm.
Next, using a Nikon Corporation stepper S203B (numerical aperture; 0.68), exposure was performed with a KrF excimer laser, and then PEB was performed under the conditions shown in Table 2. Thereafter, a 2.38 mass% tetramethylammonium hydroxide aqueous solution was used and developed by the paddle method at 23 ° C. for 1 minute, and then washed with pure water and dried to form a resist pattern. Table 2 shows the evaluation results of each resist.

Here, each resist was evaluated in the following manner.
[Depth of focus] (process margin)
It was formed when exposure was performed by changing the depth of focus from -1.0 μm to +1.0 μm in increments of 0.1 μm through an optimum exposure dose through a line and space pattern (1L1S) mask with a design line width of 0.13 μm. The focal depth range from the resist pattern line width from 0.117 μm (−10%) to 0.143 μm (+ 10%) was defined as the focal depth margin.
[Line edge roughness]
A line-and-space pattern (1L1S) having a design line width of 130 nm is observed with a scanning electron microscope, and the line width at the most concavity and convexity generated along the side surface of the line pattern and the design line width of 130 nm are observed. The difference was measured.
〔sensitivity〕
The resist film formed on the silicon wafer is exposed to a different exposure amount and then immediately exposed to PEB, developed, washed with water, and dried to form a resist pattern. The exposure amount for forming the space pattern (1L1S) with a one-to-one line width was set as the optimum exposure amount, and the sensitivity was evaluated based on the optimum exposure amount.

Details of each component other than the copolymers (A-1) to (A-3) and (a-1) in Table 1 are as shown below.
[Acid generator]
B-1: N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide B-2: Bis (p-phenylphenyl) iodonium-10-camphorsulfonate B-3: Bis (p-phenylphenyl) iodonium trifluoromethanesulfonate [acid diffusion controller]
C-1: N- (t-butoxycarbonyl) -2-phenylbenzimidazole [solvent]
D-1: Ethyl lactate D-2: Propylene glycol monomethyl ether acetate

Claims (3)

It contains a polymer having an organic group represented by the following general formula (1) at the end and a repeating unit represented by the following general formula (2), and a radiation-sensitive acid generator. A radiation-sensitive resin composition.

(In formula, R < ¹ >, R < ² > and R < ³ > show a C1-C4 saturated hydrocarbon group mutually independently.)

(In the formula, R ′ represents a hydrogen atom or a methyl group.) A monomer mixture containing a monomer represented by the following general formula (3) and a monomer having an acid-dissociable group is copolymerized using a radical generator represented by the following general formula (4). Then, a copolymer obtained by converting the repeating unit derived from the monomer represented by the general formula (3) into a repeating unit having a phenolic hydroxyl group using a base catalyst, a radiation-sensitive acid generator, A radiation-sensitive resin composition comprising:

(In the formula, R ″ represents a hydrogen atom or a methyl group, and R ⁴ represents a saturated hydrocarbon group having 1 to ⁴ carbon atoms.)

(In the formula, R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a saturated hydrocarbon group having 1 to 4 carbon atoms.) The radiation-sensitive resin composition according to claim 2, wherein the monomer having an acid dissociable group is at least one selected from compounds represented by the following general formulas (5) and (6).

(In the formula, R ¹¹ represents a hydrogen atom or a methyl group, and R ¹² , R ¹³ and R ¹⁴ each independently represent a saturated hydrocarbon group having 1 to 4 carbon atoms.)

[Wherein, R ¹⁵ represents a hydrogen atom or a methyl group. R ¹⁶ , R ¹⁷ and R ¹⁸ satisfy either of the following conditions (A) or (B).
(A) R ¹⁶ , R ¹⁷ and R ¹⁸ are each independently a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms. Indicate
At least one of R ¹⁶ , R ¹⁷ and R ¹⁸ is an alicyclic hydrocarbon group or a derivative thereof.
(B) R ¹⁶ , R ¹⁷ and R ¹⁸ are each independently a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms. Indicate
And any two of R ¹⁶ , R ¹⁷ and R ¹⁸ are bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof together with the carbon atoms to which each is bonded. And
The remaining one is a linear or branched alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof. ]