JP2011059516A - Radiation-sensitive resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition as a material for a resist film with which a resist pattern having a small LWR (line width roughness) and a wide DOF (depth of focus) can be formed. <P>SOLUTION: The radiation-sensitive resin composition contains a polymer (A) having a repeating unit expressed by formula (1) by not less than 40 mol%, and an acid generator (B). In formula (1), R<SP>1</SP>represents a hydrogen atom or the like; R<SP>2</SP>represents an alkyl group; R<SP>3</SP>represents a carbon atom; and Z represents an alicyclic skeleton. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radiation sensitive resin composition. More specifically, a resist film having characteristics such as moderate sensitivity, excellent resolution performance, moderately short diffusion length, low line width roughness, and a resist pattern with a wide focal depth. The present invention relates to a radiation-sensitive resin composition as a material.

  Conventionally, a photolithography technique using a chemically amplified radiation-sensitive resin composition has been used in the manufacture of semiconductors such as ICs and the manufacture of circuit boards such as liquid crystals and thermal heads. This chemically amplified radiation sensitive resin composition is irradiated with radiation such as far ultraviolet light represented by KrF excimer laser or ArF excimer laser (exposure). Part) is a composition that forms a resist pattern on a substrate by changing the dissolution rate of an exposed part and an unexposed part in a developing solution by a reaction using this acid as a catalyst. As such a radiation sensitive resin composition, what contains a specific polymer and a radiation sensitive acid generator is known (for example, refer patent document 1).

  The properties required for the radiation-sensitive acid generator contained in the chemically amplified radiation-sensitive resin composition include (1) excellent transparency to radiation and a high quantum yield in acid generation. (2) The generated acid is sufficiently strong, (3) The diffusion distance of the generated acid in the resist film (hereinafter sometimes referred to as “diffusion length”) is appropriate, (4) Occurrence The compatibility between the acid to be used and the resin (polymer) having an acid dissociable group is high.

  Among these, in order to achieve (2) strong acid, (3) appropriate diffusion length, and (4) high compatibility with a resin having an acid dissociable group, In ionic radiation-sensitive acid generators, the structure of the anion moiety is important, and in the nonionic radiation-sensitive acid generator having a normal sulfonyl structure or sulfonate structure, the structure of the sulfonyl moiety is important.

  For example, a resist film containing a radiation-sensitive acid generator having a trifluoromethanesulfonyl structure or a nonafluorobutanesulfonyl structure is a sufficiently strong acid generated by exposure, so that sufficient sensitivity as a photoresist can be obtained. However, because of the long acid diffusion length and the high fluorine content, it has poor compatibility with resins with acid-dissociable groups, so it is an indicator of variations in resist pattern line width. There is a problem that characteristics such as low line width roughness (LWR) and depth of focus (DOF) are deteriorated.

  In addition, a resist film containing a radiation-sensitive acid generator having a sulfonyl structure bonded to a large organic group such as a 10-camphorsulfonyl structure has a sufficiently high carbon content of acid generated by exposure, and has an acid dissociation property. There is an advantage that the compatibility with the resin having a group is relatively good and the diffusion length of the acid is moderately short, but the acid strength is not sufficient, so the resolution performance as a photoresist is not sufficient. In addition, since the sensitivity is not sufficient, there is a problem that it is not practical.

JP-B-2-27660

  As described above, resist films having various properties depending on the type of the radiation-sensitive acid generator contained are known, but there is still room for improvement, in particular, with an appropriate sensitivity and resolution performance. Therefore, there has been a demand for the development of a resist film that is excellent in resistance, has a suitably short diffusion length, has a low LWR, and can form a resist pattern having a wide DOF. Accordingly, development of the resist coating material (radiation sensitive resin composition) has been eagerly desired.

  The present invention has been made in order to solve the above-described problems of the prior art, and has characteristics such as moderate sensitivity, excellent resolution performance, and a moderately short diffusion length, and a low LWR, And it aims at providing the radiation sensitive resin composition which is the material of the resist film which can form a resist pattern with wide DOF.

  The present invention provides the following radiation-sensitive resin composition.

[1] A polymer (A) having 40% by mole or more of a repeating unit represented by the following general formula (1) (hereinafter sometimes referred to as “repeating unit (1)”) with respect to all repeating units. (Hereinafter simply referred to as “polymer (A)”) and a radiation-sensitive acid generator (B) that generates a sulfonic acid having an alicyclic skeleton having 10 or more carbon atoms (hereinafter simply referred to as “acid”). A radiation-sensitive resin composition, which may be referred to as “generating agent (B)”.

（前記一般式（１）中、Ｒ^１は、水素原子またはメチル基を示し、Ｒ^２は、炭素数１〜４の直鎖状または分岐状のアルキル基を示し、Ｒ^３は炭素原子を示す。Ｚは、炭素数１０以上の脂環式骨格を示す。）

(In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a linear or branched alkyl group having 1 to 4 carbon atoms, and R ³ represents a carbon atom. Z represents an alicyclic skeleton having 10 or more carbon atoms.)

[2] The above-mentioned [1], wherein the radiation-sensitive acid generator (B) is a compound represented by the following general formula (2) (hereinafter sometimes referred to as “compound (2)”). Radiation sensitive resin composition.

（前記一般式（２）中、Ｒ^４は、炭素数１０以上の脂環式骨格を含む１価の炭化水素基を示す。Ａは、−Ｏ−、−ＣＯＯ−または−ＯＣＯ−で表される結合基を示す。Ｘは、分子中の水素原子の少なくとも一部が置換されていても良い炭素数１〜２０の２価の直鎖状または分岐鎖状の炭化水素基を示す。ｋは、０または１を示す。Ｍ^＋は、１価のオニウムカチオンを示す。）

(In the general formula (2), R ⁴ represents a monovalent hydrocarbon group containing an alicyclic skeleton having 10 or more carbon atoms. A is represented by —O—, —COO— or —OCO—. X represents a divalent linear or branched hydrocarbon group having 1 to 20 carbon atoms in which at least a part of hydrogen atoms in the molecule may be substituted, and k represents , 0 or 1. M ⁺ represents a monovalent onium cation.)

[3] The radiation sensitive resin composition according to [2], wherein the alicyclic skeleton in R ^{4 of the} compound represented by the general formula (2) is an adamantane skeleton.

[4] The radiation-sensitive resin composition according to [2] or [3], wherein the compound represented by the general formula (2) is a compound represented by the following general formula (2-1).

（前記一般式（２−１）中、各Ｒ^５は、相互に独立に、置換されていても良い炭素数１〜８の炭化水素基を示す。各Ｒ^６は、置換されていても良い炭素数１〜８の炭化水素基を示す。各Ｒ^７は、フッ素原子または炭素数１〜４のパーフルオロアルキル基を示す。各ｌは、相互に独立に、０〜４の整数を示し、ｍは１〜４の整数を示し、ｎは０〜１０の整数を示す。Ｍ^＋は１価のオニウムカチオンを示す。）

(In said general formula (2-1), each R < ⁵ > shows the C1-C8 hydrocarbon group which may be substituted mutually independently. Each R < ⁶ > may be substituted. Represents a hydrocarbon group having 1 to 8 carbon atoms, each R ⁷ represents a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms, each l independently represents an integer of 0 to 4; m represents an integer of 1 to 4, n represents an integer of 0 to 10. M ⁺ represents a monovalent onium cation.)

[5] The feeling according to any one of [2] to [4], wherein the M ⁺ is a sulfonium cation represented by the following general formula (3) or an iodonium cation represented by the following general formula (4). Radiation resin composition.

（前記一般式（３）中、Ｒ^８、Ｒ^９、及びＲ^１０は、相互に独立に、置換されていても良い炭素数１〜１０の直鎖状若しくは分岐状のアルキル基、または、置換されていても良い炭素数６〜１８のアリール基を示すか、或いは、Ｒ^８、Ｒ^９、及びＲ^１０はのうちのいずれか２つが相互に結合して前記一般式（３）中のイオウ原子とともに環状構造を形成しており、残りが置換されていても良い炭素数１〜１０の直鎖状若しくは分岐状のアルキル基、または、置換されていても良い炭素数６〜１８のアリール基を示す。）

(In the general formula ^{(3), R 8, R} 9, and ^{R 10} are independently of each other, linear or branched alkyl group substituted carbon atoms and optionally 1 to 10 or a substituted Or an aryl group having 6 to 18 carbon atoms, or any two of R ⁸ , R ⁹ and R ¹⁰ may be bonded to each other to form sulfur in the general formula (3). A linear structure or a branched alkyl group having 1 to 10 carbon atoms that may form a cyclic structure together with atoms, and the remainder may be substituted, or an aryl group having 6 to 18 carbon atoms that may be substituted Is shown.)

（前記一般式（４）中、Ｒ^１１及びＲ^１２は、相互に独立に、置換されていても良い炭素数１〜１０の直鎖状若しくは分岐状のアルキル基、または、置換されていても良い炭素数６〜１８のアリール基を示すか、或いは、Ｒ^１１及びＲ^１２が相互に結合して前記一般式（４）中のヨウ素原子とともに環状構造を形成している。）

(In the general formula (4), R ¹¹ and R ¹² are each independently a linear or branched alkyl group having 1 to 10 carbon atoms which may be substituted, or may be substituted. It is a good aryl group having 6 to 18 carbon atoms, or R ¹¹ and R ¹² are bonded to each other to form a cyclic structure together with the iodine atom in the general formula (4).

[6] The radiation-sensitive resin composition according to any one of [1] to [5], wherein Z in the general formula (1) is an adamantane skeleton.

  The radiation-sensitive resin composition of the present invention has an effect of being a resist film material capable of forming a resist pattern having moderate sensitivity, low LWR, and wide DOF.

  Hereinafter, although the form for implementing this invention is demonstrated, this invention is not limited to the following embodiment. That is, it is understood that modifications and improvements as appropriate to the following embodiments are also within the scope of the present invention based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should be.

[1] Radiation sensitive resin composition:
The radiation sensitive resin composition of the present invention contains a polymer (A) and an acid generator (B), and such a composition comprises a polymer (A) and an acid generator (B). Can be used as a resist coating material capable of forming a resist pattern having a moderate sensitivity, a low LWR, and a wide DOF.

[1-1] Polymer (A):
The polymer (A) has 40 mol% or more of the repeating unit represented by the general formula (1) with respect to all repeating units, and such a polymer (A) has a carbon content. Therefore, depending on the radiation sensitive acid generator to be combined, the compatibility between the polymer (A) and the radiation sensitive acid generator may be lowered. Therefore, the radiation sensitive resin composition which has the said effect can be obtained by using an acid generator (B) as a radiation sensitive acid generator, and combining with this acid generator (B).

[1-1-1] Repeating unit (1):
Examples of the linear or branched alkyl group having 1 to 4 carbon atoms of R ^{2 in} the general formula (1) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and an n-butyl group. , 1-methylpropyl group, 2-methylpropyl group, and t-butyl group. Among these alkyl groups, since they have an appropriate leaving ability (that is, the degree of ease of deprotection when the protecting group is deprotected), the methyl group and the ethyl group are preferable.

Examples of the alicyclic skeleton of Z having 10 or more carbon atoms include adamantane, bicyclo [2.2.1] heptane, tricyclo [4.3.0.1 ^2,5 ] decane, and tetracyclo [4.4.0. .1 ^2,5 . And a skeleton derived from ^{17, 10} ] dodecane and the like. Among these skeletons, a skeleton derived from adamantane (that is, an adamantane skeleton) is preferable because it has appropriate desorption ability and heat resistance. R ³ is one of carbon atoms constituting the alicyclic skeleton represented by Z.

  Specific examples of the repeating unit (1) include a repeating unit represented by the following general formula (1-1) (hereinafter sometimes referred to as “repeating unit (1-1)”). it can.

（上記一般式（１−１）中、Ｒ^１は、水素原子またはメチル基を示し、Ｒ^２は、炭素数１〜４の直鎖状または分岐状のアルキル基を示す。Ｒ^１３は、水素原子または炭素数１〜４の直鎖状または分岐状のアルキル基を示す。）

(In the general formula (1-1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a linear or branched alkyl group having 1 to 4 carbon atoms. R ¹³ represents hydrogen. An atom or a linear or branched alkyl group having 1 to 4 carbon atoms is shown.)

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms of R ^{13 in} the general formula (1-1) include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n- Examples thereof include a butyl group, a 1-methylpropyl group, a 2-methylpropyl group, and a t-butyl group.

  In addition, the repeating unit (1) can have 1 type individually or 2 types or more.

  The content ratio of the repeating unit (1) needs to be 40 mol% or more with respect to all the repeating units in the polymer (A), and preferably 40 to 70 mol%. More preferably, it is mol%. When the content ratio is 40 mol% or more, the carbon content in the polymer (A) increases, and the compound represented by the general formula (2) (radiation-sensitive acid generator (B)) Since compatibility improves, the radiation sensitive resin composition which has the said effect can be obtained.

[1-1-2] Other repeating units:
The polymer (A) preferably contains, in addition to the repeating unit (1), a repeating unit having a lactone structure or a cyclic carbonate structure (hereinafter sometimes referred to as “repeating unit (5)”). If the repeating unit (5) is further contained, the adhesiveness to the substrate is improved, so that there is an advantage that the resist pattern is hardly collapsed.

Examples of the repeating unit (5) having a lactone structure include repeating units (5-1) to (5-16) represented by the following general formulas (5-1) to (5-16). In general formulas (5-1) to (5-16), R ¹ represents a hydrogen atom or a methyl group.

  Of these, a repeating unit containing a lactone ring bonded to a polycyclic alicyclic hydrocarbon group is particularly preferable. The repeating units (5-1), (5-3), and (5-7) to (5-13) are examples of repeating units including a lactone ring bonded to a norbornene ring. -4) is an example of a repeating unit containing a bicyclo [2.2.2] octane ring.

As a monomer for constituting the repeating unit (5) having a lactone structure, for example, (meth) acrylic acid-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] nona -2-yl ester, (meth) acrylic acid-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester, (meth) acrylic acid -5-oxo-4-oxa-tricyclo [5.2.1.0 ^3,8 ] dec-2-yl ester, (meth) acrylic acid-10-methoxycarbonyl-5-oxo-4-oxa-tricyclo [ 5.2.1.0 ^3,8 ] non-2-yl ester, (meth) acrylic acid-6-oxo-7-oxa-bicyclo [3.2.1] oct-2-yl ester, (meth) Acrylic acid-4-methoxy Rubonyl-6-oxo-7-oxa-bicyclo [3.2.1] oct-2-yl ester, (meth) acrylic acid-7-oxo-8-oxa-bicyclo [3.3.1] octa-2 -Yl esters,

  (Meth) acrylic acid-4-methoxycarbonyl-7-oxo-8-oxa-bicyclo [3.3.1] oct-2-yl ester, (meth) acrylic acid-2-oxotetrahydropyran-4-yl ester , (Meth) acrylic acid-4-methyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-ethyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4 -Propyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2,2-dimethyl-5-oxotetrahydrofuran-3-yl Ester, (meth) acrylic acid-4,4-dimethyl-5-oxotetrahydrofuran-3-yl ester, (Meth) acrylic acid-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-4,4-dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5,5-dimethyl-2 -Oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid-3, Examples thereof include 3-dimethyl-5-oxotetrahydrofuran-2-ylmethyl ester and (meth) acrylic acid-4,4-dimethyl-5-oxotetrahydrofuran-2-ylmethyl ester.

  Moreover, as a repeating unit (5) which has a cyclic carbonate structure, the repeating unit represented by the following general formula (5A) can be mentioned.

（上記一般式（５Ａ）中、Ｒ^１は、水素原子またはメチル基を示し、Ｂは単結合、炭素数が１〜３０である２価の鎖状炭化水素基、炭素数が３〜３０である２価の脂環式炭化水素基又は炭素数が６〜３０である２価の芳香族炭化水素基を示し、Ｙは下記式（ｉ）で表される構造を有する１価の基を示す。）

(In the general formula (5A), R ¹ represents a hydrogen atom or a methyl group, B represents a single bond, a divalent chain hydrocarbon group having 1 to 30 carbon atoms, and 3 to 30 carbon atoms. A divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms is represented, and Y represents a monovalent group having a structure represented by the following formula (i). .)

（上記式（ｉ）中、Ｒ^１４は、水素原子または炭素数１〜５の鎖状炭化水素基を示し、ａは１または２を示し、ｂは１または２を示す。但し、Ｒ^１４が複数存在する場合には、Ｒ^１４は同一であってもよいし、異なっていてもよい。）

(In the above formula (i), R ¹⁴ represents a hydrogen atom or a chain hydrocarbon group having 1 to 5 carbon atoms, a represents 1 or 2, and b represents 1 or 2, provided that R ¹⁴ represents When there are a plurality of R ^{14 s} , R ¹⁴ may be the same or different.)

  Examples of the divalent chain hydrocarbon group having 1 to 30 carbon atoms represented by B in the general formula (5A) include a methylene group, an ethylene group, a 1,2-propylene group, 1,3. -Propylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, penta Linear alkylene groups such as decamethylene group, hexadecamethylene group, heptacamethylene group, octadecamethylene group, nonadecamethylene group, icosalen group; 1-methyl-1,3-propylene group, 2-methyl-1 , 3-propylene group, 2-methyl-1,2-propylene group, 1-methyl-1,4-butylene group, 2-methyl-1,4-butylene Down group, methylidene group, ethylidene group, propylidene group, and the like can be given branched alkylene group such as 2-propylidene group.

  Examples of the divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms include 1,3-cyclobutylene group, 1,3-cyclopentylene group, 1,4-cyclohexylene group, Monocyclic cycloalkylene group having 3 to 10 carbon atoms such as 1,5-cyclooctylene group; 1,4-norbornylene group, 2,5-norbornylene group, 1,5-adamantylene group, 2,6-adaman Examples thereof include polycyclic cycloalkylene groups such as a tylene group.

  Examples of the divalent aromatic hydrocarbon group having 6 to 30 carbon atoms include arylene groups such as a phenylene group, a tolylene group, a naphthylene group, a phenanthrylene group, and an anthrylene group.

  The monovalent group having a structure represented by the formula (i) is a monovalent group having at least a part of a cyclic carbonate structure. As the monovalent group having the structure represented by the formula (i), a group in which the structure represented by the formula (i) is directly bonded to B in the general formula (5A) (the following repeating unit (5- 17) to (5-22)) and other groups having the above-mentioned cyclic carbonate structure and other polycyclic structures (the following repeating units (5-23) to (5-30) and (5-32) to (5) -37))). In addition, the structure represented by the formula (i) and the polycyclic structure are those having a substituent (the following repeating units (5-18), (5-21), (5-22), (5-29) , (5-34), (5-36)), or having a divalent group between B in the general formula (5A) (see the following repeating unit (5-31)) It may be.

  The monovalent group having the structure represented by formula (i) preferably has 3 to 30 carbon atoms, more preferably 3 to 15 carbon atoms, and more preferably 3 to 10 carbon atoms. It is particularly preferred to have When it has more than 30 carbon atoms, the adhesiveness of the resist film to be formed is lowered, and there is a risk of pattern collapse or pattern peeling. In addition, the solubility of the polymer component in the developer may be reduced, which may cause development defects.

  Examples of the repeating unit (5) having a cyclic carbonate structure include repeating units (5-17) to (5-37) represented by the following general formulas (5-17) to (5-37). . Of these, the repeating unit (5-17) is preferred.

  In addition, 1 type in the repeating unit (5) mentioned above may be contained independently in the polymer (A), and 2 or more types may be contained.

  The content of the repeating unit (5) is preferably 20 to 60 mol%, more preferably 30 to 60 mol%, more preferably 40 to 50 mol% based on all repeating units in the polymer (A). It is particularly preferred that it is mol%. If the content ratio is less than 20 mol%, the adhesion of the formed resist film to the substrate is lowered, so that the resist pattern may be easily collapsed. On the other hand, if it exceeds 60 mol%, the solubility of the polymer (A) in the developer is lowered, so that the resolution may be lowered.

  The polymer (A) can further contain other repeating units. Other repeating units include a repeating unit represented by the following general formula (6) (hereinafter sometimes referred to as “repeating unit (6)”), a repeating unit represented by the following general formula (7) (however, , Except for the repeating unit (1)) (hereinafter may be referred to as “repeating unit (7)”).

In general formula (6) and general formula (7), each R < ¹ > shows a hydrogen atom or a methyl group mutually independently. In the general formula (6), each R ¹⁵ is independently a hydrogen atom, a hydroxyl group, a cyano group, or —COOR ¹⁷ (where R ¹⁷ is a hydrogen atom, a linear or branched group having 1 to 4 carbon atoms). Represents an alkyl group or a cyclic alkyl group having 3 to 20 carbon atoms.). In the general formula (7), each R ¹⁶ independently represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms. Or any two of R ¹⁶ 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. The remaining R ¹⁶ represents 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 for constituting the repeating unit (6) include adamantane-1-yl (meth) acrylate, 3-methyladamantan-1-yl (meth) acrylate, and (meth) acrylic acid 3- Ethyladamantan-1-yl, 3-hydroxyadamantan-1-yl (meth) acrylate, 3,5-dihydroxyadamantan-1-yl (meth) acrylate, 3-cyanoadamantan-1-yl (meth) acrylate 3-methacrylic acid 3-carboxyadamantan-1-yl, (meth) acrylic acid 3,5-dicarboxyadamantan-1-yl, (meth) acrylic acid 3-carboxy-5-hydroxyadamantan-1-yl, (Meth) acrylic acid 3-methoxycarbonyl-5-hydroxyadamantan-1-yl and the like can be mentioned.

  It is preferable that the content rate of a repeating unit (6) is 0-20 mol% with respect to all the repeating units in a polymer (A).

  When the repeating unit (6) is further contained, the solubility of the polymer (A) in the developing solution is improved, so that there is an advantage that the resolution is improved.

  As a monomer for constituting the repeating unit (7), for example, t-butyl (meth) acrylate, 1-methylcyclopentyl (meth) acrylate, 1-ethylcyclopentyl (meth) acrylate, (meth) Examples thereof include 1-methylcyclohexyl acrylate and 1-ethylcyclohexyl (meth) acrylate.

  It is preferable that the content rate of a repeating unit (7) is 0-40 mol% with respect to all the repeating units in a polymer (A).

[1-1-3] Synthesis of polymer (A):
The polymer (A) can be synthesized according to a conventionally known method such as radical polymerization. For example, a reaction solution containing each monomer and a radical initiator is reacted with a reaction solvent or a monomer-containing reaction. A method of performing a polymerization reaction by dropping into a solution, a reaction solution containing each monomer and a reaction solution containing a radical initiator are separately dropped into a reaction solution containing a reaction solvent or a monomer and polymerized. Method of reaction, reaction solution prepared separately for each monomer and reaction solution containing a radical initiator are dropped into a reaction solution containing a reaction solvent or a monomer, respectively, to cause a polymerization reaction The method etc. can be mentioned.

  The reaction temperature in each of the above reactions can be appropriately set depending on the type of the initiator, but is preferably 30 to 180 ° C, more preferably 40 to 160 ° C, and particularly preferably 50 to 140 ° C. The time required for dropping can be appropriately set depending on the reaction temperature, the type of initiator, and the monomer to be reacted, but it is preferably 30 minutes to 8 hours, and more preferably 45 minutes to 6 hours. It is particularly preferably 1 hour to 5 hours. The total reaction time including the dropping time can be appropriately set, but is preferably 30 minutes to 8 hours, more preferably 45 minutes to 7 hours, and 1 hour to 6 hours. Is particularly preferred. When dropping into the solution containing the monomer, the content ratio of the monomer in the dropped solution is preferably 30 mol% or more, and 50 mol% or more with respect to the total amount of monomers used for the polymerization. It is more preferable that it is 70 mol% or more.

  As radical initiators used for polymerization, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2-cyclopropylpropionitrile), 2,2 '-Azobis (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1 -Carbonitrile), 2,2′-azobis (2-methyl-N-phenylpropionamidine) dihydrochloride, 2,2′-azobis (2-methyl-N-2-propenylpropionamidine) dihydrochloride, 2,2 '-Azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis {2-methyl-N- [ , 1-bis (hydroxymethyl) 2-hydroxyethyl] propionamide}, dimethyl-2,2′-azobis (2-methylpropionate), 4,4′-azobis (4-cyanovaleric acid), 2, And 2'-azobis (2- (hydroxymethyl) propionitrile). These initiators can be used alone or in combination of two or more.

  The solvent used for the polymerization can be used unless it dissolves the monomer to be used and does not inhibit the polymerization (for example, nitrobenzenes, mercapto compounds). For example, alcohols, ethers, ketones, amides, esters, lactones, nitriles, a mixed solution thereof, and the like can be given.

  Examples of alcohols include methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and 1-methoxy-2-propanol. Examples of ethers include propyl ether, isopropyl ether, butyl methyl ether, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, 1,3-dioxane and the like. Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, methyl isopropyl ketone, and methyl isobutyl ketone. Examples of amides include N, N-dimethylformamide and N, N-dimethylacetamide. Examples of the esters include ethyl acetate, methyl acetate, and isobutyl acetate. Examples of lactones include γ-butyrolactone. Examples of nitriles include acetonitrile, propionitrile, butyronitrile, and the like. In addition, these solvent can be used individually by 1 type or 2 types or more.

  After completion of the polymerization, it is preferable to throw the reaction solution into a reprecipitation solvent and recover the target polymer as a powder. Examples of the reprecipitation solvent include water, alcohols, ethers, ketones, amides, esters, lactones, nitriles, and mixed liquids thereof. Examples of alcohols include methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, propylene glycol, and 1-methoxy-2-propanol. Examples of ethers include propyl ether, isopropyl ether, butyl methyl ether, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, 1,3-dioxane and the like. Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, methyl isopropyl ketone, and methyl isobutyl ketone. Examples of amides include N, N-dimethylformamide and N, N-dimethylacetamide. Examples of the esters include ethyl acetate, methyl acetate, and isobutyl acetate. Examples of lactones include γ-butyrolactone. Examples of nitriles include acetonitrile, propionitrile, butyronitrile, and the like.

  The polymer (A) preferably has a weight average molecular weight (hereinafter sometimes referred to as “Mw”) measured by gel permeation chromatography of 1,000 to 100,000, preferably 1,500 to 80, Is more preferably 2,000, and particularly preferably 2,000 to 50,000. There exists a possibility that the heat resistance of a resist film may fall that Mw of the said polymer (A) is less than 1,000. On the other hand, if it exceeds 100,000, the developability of the resist film may be lowered. The ratio (Mw / Mn) of Mw of the polymer (A) to the number average molecular weight (hereinafter sometimes referred to as “Mn”) is preferably 1 to 5, and preferably 1 to 3. More preferably.

  In addition, the polymerization reaction liquid obtained by the said polymerization is so preferable that there are few impurities, such as a halogen and a metal. This is because a lower impurity content can further improve sensitivity, resolution, process stability, pattern shape, and the like when a resist film is formed. Examples of the purification method of the polymerization reaction solution include chemical purification methods such as washing with water and liquid-liquid extraction, and combinations of these chemical purification methods with physical purification methods such as ultrafiltration and centrifugation. Can do. In the present invention, the polymer (A) may be used alone or in combination of two or more.

[1-2] Acid generator (B):
The acid generator (B) generates sulfonic acid having an alicyclic skeleton having 10 or more carbon atoms. That is, such an acid generator (B) generates sulfonic acid having an alicyclic skeleton having 10 or more carbon atoms when irradiated with radiation, and by generating the sulfonic acid, The polymer (A) becomes alkali-soluble. At this time, since the sulfonic acid generated from the acid generator (B) has a strong fluorine-containing electron withdrawing group at the α-position of the sulfonyl group in the structure, the acidity is high. Further, the acid generator (B) has a high boiling point, hardly volatilizes during the photolithography process, and has a short acid diffusion length in the resist film. That is, it has a characteristic that the acid diffusion length is moderate. By using in combination with such an acid generator (B) and the polymer (A) described above, a radiation-sensitive resin composition having the above effects can be obtained.

  The acid generator (B) is not particularly limited as long as it generates a sulfonic acid having an alicyclic skeleton having 10 or more carbon atoms, but the compound represented by the general formula (2) (compound (2)) ) Is preferable. The compound (2) has an advantage that the polymer (A) is well alkali-soluble by the generated sulfonic acid. Moreover, since carbon content rate is high, there exists an advantage that compatibility with a polymer (A) improves.

Examples of the monovalent hydrocarbon group containing an alicyclic skeleton having 10 or more carbon atoms of R ^{4 in} the compound (2) include an adamantyl group, a bicyclo [2.2.1] heptyl group, and a tricyclo [4.3. .0.1 ^2,5 ] decanyl group, tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl group and the like. Among these, an adamantyl group is preferable because compatibility with the polymer (A) is improved. In addition, the alicyclic skeleton having 10 or more carbon atoms of R ⁴ is preferably an adamantane skeleton in order to improve compatibility with the polymer (A).

  Among the compounds (2), a compound represented by the general formula (2-1) (hereinafter sometimes referred to as “compound (2-1)”) is preferable. If it is a compound (2-1), there exists an advantage that a polymer (A) becomes further more alkali-soluble by the sulfonic acid to generate | occur | produce. Moreover, since carbon content rate is high, there exists an advantage that compatibility with a polymer (A) improves.

  Specifically, the compound (2-1) generates a sulfonic acid represented by the following general formula (2-1a).

（前記一般式（２−１ａ）中、各Ｒ^５は、相互に独立に、置換されていても良い炭素数１〜８の炭化水素基を示す。各Ｒ^６は、置換されていても良い炭素数１〜８の炭化水素基を示す。各Ｒ^７は、フッ素原子または炭素数１〜４のパーフルオロアルキル基を示す。各ｌは、相互に独立に、０〜４の整数を示し、ｍは１〜４の整数を示し、ｎは０〜１０の整数を示す。Ｍ^＋は１価のオニウムカチオンを示す。）

(In the general formula (2-1a), each R ^5, independently of one another, optionally substituted a hydrocarbon group having 1 to 8 carbon atoms. Each R ⁶ may be substituted Represents a hydrocarbon group having 1 to 8 carbon atoms, each R ⁷ represents a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms, each l independently represents an integer of 0 to 4; m represents an integer of 1 to 4, n represents an integer of 0 to 10. M ⁺ represents a monovalent onium cation.)

Examples of the monovalent onium cation represented by M ⁺ in the general formula (2) and the general formula (2-1) include O, S, Se, N, P, As, Sb, Cl, Br, and I. Mention may be made of onium cations. Of these onium cations, the onium cation of S or the onium cation of I is preferred. As the onium cation of S, those represented by the general formula (3) are preferable. Moreover, as an onium cation of I, what is represented by the said General formula (4) is preferable.

Examples of the optionally substituted linear or branched alkyl group having 1 to 10 carbon atoms represented by R ⁸ , R ⁹ and R ¹⁰ in the general formula (3) include a methyl group, n -A butyl group etc. can be mentioned.

Examples of the optionally substituted aryl group having 6 to 18 carbon atoms represented by R ⁸ , R ⁹ and R ¹⁰ in the general formula (3) include a phenyl group and a 4-cyclohexylphenyl group. be able to.

Among the alkyl groups and aryl groups represented by R ⁸ , R ⁹ , and R ¹⁰ in general formula (3), an aryl group is preferable because the radiation absorption efficiency is improved.

  As the sulfonium cation represented by the general formula (3), an onium cation represented by the following general formula (3-1) or (3-2) is preferable because the radiation absorption efficiency is improved.

In General Formula (3-1), R ¹⁸ , R ¹⁹ and R ²⁰ are each independently a hydroxyl group, an optionally substituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted group. An aryl group having 6 to 12 carbon atoms which may be present. q1, q2, and q3 each independently represent an integer of 0 to 5. In General Formula (3-2), R ²¹ represents a hydroxyl group, a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 8 carbon atoms. Indicates. R ²² represents a hydrogen atom, an optionally substituted linear or branched alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 7 carbon atoms, or 2 R ²² are bonded to each other to form a cyclic structure. q4 represents an integer of 0 to 7, q5 represents an integer of 0 to 6, and q6 represents an integer of 0 to 3. R ²¹ and R ²² may be the same or different.

  Specific examples of the sulfonium cation represented by the general formula (3) include cations represented by the following formulas (i-1) to (i-63).

  Among these monovalent onium cations, formula (i-1), formula (i-2), formula (i-6), formula (i-8), formula (i-13), formula (i-19) ), A sulfonium cation represented by the formula (i-25), the formula (i-27), the formula (i-29), the formula (i-33), the formula (i-51), and the formula (i-54) preferable.

  As the iodonium cation represented by the general formula (4), an onium cation represented by the following formula (4-1) is preferable because the radiation absorption efficiency is improved.

In General Formula (4-1), R ²³ and R ²⁴ are each independently a hydroxyl group, an optionally substituted linear or branched alkyl group having 1 to 12 carbon atoms, or an optionally substituted group. A good aryl group having 6 to 12 carbon atoms is shown, or two aryl groups bonded to an iodine atom are bonded to each other to form a cyclic structure together with the iodine atom. q7 and q8 each independently represent an integer of 0 to 5.

  Examples of the iodonium cation represented by the above formula (4-1) include cations represented by the following formulas (ii-1) to (ii-39).

  Among these preferable monovalent onium cations, the iodonium cation represented by the formula (ii-1) or the formula (ii-11) is preferable.

The monovalent onium cation represented by M ⁺ in the general formula (2) is described in, for example, Advances in Polymer Science, Vol. 62, p. It can be produced according to the general method described in 1-48 (1984).

  Although the usage-amount of an acid generator (B) changes with kinds of an acid generator (B) and the following other acid generator, it is 0.1-20 mass parts with respect to 100 mass parts of polymers (A). It is preferably 0.1 to 15 parts by mass, particularly preferably 0.2 to 12 parts by mass. If the amount of the acid generator (B) used is less than 0.1 parts by mass, the amount of acid generated is insufficient, and the resolution may be lowered. On the other hand, if it exceeds 20 parts by mass, the resulting resist pattern may have reduced radiation transparency and heat resistance, and a good pattern shape may not be obtained.

  In addition, an acid generator (B) can be used individually by 1 type or in combination of 2 or more types.

[1-3] Acid diffusion controller:
The radiation sensitive resin composition of the present invention may contain an acid diffusion controller. The acid diffusion control agent controls the diffusion phenomenon in the resist film of the acid generated from the acid generator by exposure, and suppresses an undesirable chemical reaction in the non-exposed region. By blending such an acid diffusion controller, the storage stability of the resulting radiation-sensitive resin composition is improved, the resolution as a resist film is further improved, and the process from exposure to heat treatment is retained. A change in the line width of the resist pattern due to fluctuations in time (PED) can be suppressed, and a radiation-sensitive resin composition having extremely excellent process stability can be obtained.

  Specific examples of the acid diffusion controller (a) include Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, and Nt-butoxycarbonyldi-n-. Decylamine, Nt-butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine , (S)-(−)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxy Carbonyl-4-hydroxypiperidine, Nt-butoxycarbonylpyrrolidine, N, N′-di-t-buto Cycarbonylpiperazine, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, Nt-butoxycarbonyl-4,4 '-Diaminodiphenylmethane, N, N'-di-t-butoxycarbonylhexamethylenediamine, N, N, N'N'-tetra-t-butoxycarbonylhexamethylenediamine, N, N'-di-t-butoxycarbonyl -1,7-diaminoheptane, N, N'-di-t-butoxycarbonyl-1,8-diaminooctane, N, N'-di-t-butoxycarbonyl-1,9-diaminononane, N, N'- Di-t-butoxycarbonyl-1,10-diaminodecane, N, N′-di-t-butoxycarbonyl-1,12-diaminode Can, N, N′-di-t-butoxycarbonyl-4,4′-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl Examples include Nt-butoxycarbonyl group-containing amino compounds such as 2-phenylbenzimidazole.

  Examples of acid diffusion control agents other than the acid diffusion control agent (a) include tertiary amine compounds, quaternary ammonium hydroxide compounds, and nitrogen-containing heterocyclic compounds.

  Examples of tertiary amine compounds include triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octyl. Tri (cyclo) alkylamines such as amine, cyclohexyldimethylamine, dicyclohexylmethylamine, tricyclohexylamine; aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methyl Aromatic amines such as aniline, 4-nitroaniline, 2,6-dimethylaniline, 2,6-diisopropylaniline; alkanolamines such as triethanolamine, N, N-di (hydroxyethyl) aniline; N, N , N ′, N′-Tetramethylethylene Amine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzenetetramethylenediamine, bis (2- Examples thereof include dimethylaminoethyl) ether and bis (2-diethylaminoethyl) ether.

  Examples of the quaternary ammonium hydroxide compound include tetra-n-propylammonium hydroxide and tetra-n-butylammonium hydroxide.

  Examples of the nitrogen-containing heterocyclic compound include pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4-phenylpyridine. , Nicotine, nicotinic acid, nicotinamide, quinoline, 4-hydroxyquinoline, 8-oxyquinoline, acridine and other pyridines; piperazine, piperazines such as 1- (2-hydroxyethyl) piperazine, pyrazine, pyrazole, Pyridazine, quinosaline, purine, pyrrolidine, piperidine, 3-piperidino-1,2-propanediol, morpholine, 4-methylmorpholine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane, imidazole 4-methylimidazole, 1 Benzyl-2-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole, and the like 2-phenylbenzimidazole.

  In addition, the acid diffusion control agent can be used alone or in combination of two or more.

  The amount of the acid diffusion controller used is preferably 10 parts by mass or less with respect to 100 parts by mass of the polymer (A) from the viewpoint that high sensitivity as a resist film can be secured. More preferably, it is -5 mass parts. There exists a possibility that the sensitivity of a resist film may fall remarkably that the said usage-amount exceeds 10 mass parts. In addition, the improvement effect may not be acquired unless the usage-amount of an acid diffusion control agent is 0.001 mass part or more.

[1-4] Solvent:
The radiation-sensitive resin composition of the present invention usually contains a solvent. Specific examples of the solvent include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether. Ethylene glycol monoalkyl ether acetates such as acetate and ethylene glycol mono-n-butyl ether acetate; Propylene such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether Glycol monoalkyl ethers; propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n Propylene glycol dialkyl ethers such as propyl ether and propylene glycol di-n-butyl ether; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-n-butyl ether acetate, etc. Of propylene glycol monoalkyl ether acetates;

  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, cyclohexanone; N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethyl Examples thereof include amides such as acetamide and N-methylpyrrolidone; lactones such as γ-butyrolacun. These solvents can be used alone or in combination of two or more.

[1-5] Other additives:
The radiation-sensitive resin composition of the present invention includes an alicyclic additive having an acid-dissociable group, a surfactant, a sensitizer, an alkali-soluble resin, and a low-molecular alkali solubility having an acid-dissociable protective group. Other additives such as a control agent, an antihalation agent, a storage stabilizer, and an antifoaming agent can be further contained.

  The alicyclic additive having an acid dissociable group is a component having an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like. Examples of such alicyclic additives include 1-adamantanecarboxylate t-butyl, 1-adamantanecarboxylate t-butoxycarbonylmethyl, 1,3-adamantanedicarboxylate di-t-butyl, 1-adamantaneacetic acid. adamantane derivatives such as t-butyl, 1-adamantane acetate t-butoxycarbonylmethyl, 1,3-adamantanediacetate di-t-butyl; deoxycholate t-butyl, deoxycholate t-butoxycarbonylmethyl, deoxychol Deoxycholic acid esters such as 2-ethoxyethyl acid, 2-cyclohexyloxyethyl deoxycholic acid, 3-oxocyclohexyl deoxycholic acid, tetrahydropyranyl deoxycholic acid, mevalonolactone ester deoxycholic acid; t-butyl lithocholic acid , List of lithocholic acid esters such as t-butoxycarbonylmethyl cholic acid, 2-ethoxyethyl lithocholic acid, 2-cyclohexyloxyethyl lithocholic acid, 3-oxocyclohexyl lithocholic acid, tetrahydropyranyl lithocholic acid, mevalonolactone ester of lithocholic acid be able to. In addition, these alicyclic additives can be used alone or in combination of two or more.

  Further, the surfactant is a component having an action of improving applicability, striation, developability and the like. Examples of such surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, and polyethylene glycol dilaurate. And nonionic surfactants such as polyethylene glycol distearate. Commercially available surfactants are all trade names below, such as KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.), Ftop EF301, EF303, EF352 (manufactured by Tochem Products), Megafax F171, F173 (manufactured by Dainippon Ink and Chemicals), Florard FC430, FC431 (Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (manufactured by Asahi Glass Co., Ltd.), etc. Can do. These surfactants can be used alone or in combination of two or more.

[2] Method for producing radiation-sensitive resin composition:
The radiation-sensitive resin composition of the present invention includes, for example, a raw material composition containing a polymer (A), an acid generator (B), an acid diffusion controller, and other additives, and its total solid content concentration. Can be obtained by dissolving in a solvent so as to be 3 to 50% by mass (preferably 5 to 25% by mass) and then filtering with a filter having a pore diameter of about 200 nm.

[3] Method for forming resist pattern:
The radiation sensitive resin composition of the present invention is particularly useful as a chemically amplified resist. Below, the formation method of the resist pattern using the radiation sensitive resin composition of this invention is demonstrated. First, a resist film made of the radiation sensitive resin composition of the present invention is formed on a substrate. Thereafter, the formed resist film is exposed. Here, the acid dissociable group in the polymer (A) is dissociated by the action of the sulfonic acid generated from the acid generator (B) by exposure to generate a carboxyl group. When the carboxyl group is generated, the solubility in an alkali developer in the exposed portion of the resist film is increased. Thereafter, by developing the resist film, that is, by dissolving and removing the exposed portion with an alkaline developer, a positive resist pattern can be formed. The resist pattern forming method will be described more specifically below.

  First, a radiation sensitive resin composition (composition solution) is prepared by the method described above. A resist film is formed by applying the prepared composition solution onto a substrate such as a silicon wafer or a wafer coated with aluminum by an appropriate application means such as spin coating, cast coating, or roll coating. .

  Thereafter, in some cases, after heat treatment (hereinafter referred to as “SB”) in advance, the resist film is exposed to form a predetermined resist pattern. As the radiation used for exposure, visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams and the like can be selected as appropriate. ArF excimer laser (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm) In particular, a far ultraviolet ray represented by the formula (1) is preferable, and an ArF excimer laser (wavelength 193 nm) is particularly preferable. Further, it is preferable to perform a heat treatment (hereinafter referred to as “PEB”) after exposure. By this PEB, the dissociation reaction of the acid dissociable group in the resist film proceeds smoothly. The heating conditions for PEB vary depending on the composition of the radiation-sensitive resin composition, but are preferably 30 to 200 ° C, and more preferably 50 to 170 ° C.

  In addition, the radiation sensitive resin composition of the present invention is organic or organic on the substrate to be used, for example, as disclosed in Japanese Patent Publication No. 6-12452, etc., in order to maximize the potential. An inorganic antireflection film can also be formed. Further, in order to prevent the influence of basic impurities contained in the environmental atmosphere, a protective film can be provided on the resist film as disclosed in, for example, JP-A-5-188598. These techniques can be used in combination.

  Next, a predetermined resist pattern can be obtained by developing the exposed resist film. Examples of the developer used for development include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, and di-n-propylamine. , Triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene and 1,5-diazabicyclo- [4.3.0] An alkaline aqueous solution in which at least one of alkaline compounds such as 5-nonene is dissolved is preferable. The concentration of the alkaline aqueous solution is preferably 10% by mass or less. If the concentration of the alkaline aqueous solution is more than 10% by mass, the unexposed area may be dissolved in the developer.

  Further, for example, an organic solvent can be added to the developer. Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone, methyl i-butyl ketone, cyclopentanone, cyclohexanone, 3-methylcyclopentanone, and 2,6-dimethylcyclohexanone; methyl alcohol, ethyl alcohol, and n-propyl. Alcohols such as alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol, 1,4-hexanedimethylol; ethers such as tetrahydrofuran and dioxane Esters such as ethyl acetate, n-butyl acetate and i-amyl acetate; aromatic hydrocarbons such as toluene and xylene; phenol, acetonylacetone and dimethylformamide. In addition, these organic solvents can be used alone or in combination of two or more.

  It is preferable that the usage-amount of an organic solvent is 100 volume% or less with respect to the said alkaline aqueous solution. If the amount of the organic solvent used is more than 100% by volume, the developability is lowered, and there is a risk that the remaining development in the exposed area will increase. Further, an appropriate amount of the above-described surfactant or the like can be added to the developer. In addition, after developing with the said developing solution, it is preferable to wash | clean and dry with water.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to these Examples and a comparative example. In the description of Examples, “parts” and “%” are based on mass unless otherwise specified. Moreover, each measurement and evaluation in each Example and a comparative example were performed in the following way.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]:
The weight average molecular weight (Mw) and the number average molecular weight (Mn) are GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation, flow rate 1.0 ml / min, elution solvent tetrahydrofuran, column temperature 40 ° C. The measurement was performed by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard. Further, the dispersity (Mw / Mn) was calculated from the above measurement results.

[ ¹³ C-NMR analysis]:
The ¹³ C-NMR analysis of each polymer was performed using “JNM-EX270” manufactured by JEOL Ltd.

[sensitivity]:
A silicon wafer (ARC29) having a film of “ARC29” (manufactured by Brewer Science) having a film thickness of 780 Å on the wafer surface is used as a substrate, and each composition solution is applied onto the substrate by spin coating. did. Thereafter, a pre-exposure heat treatment (SB (Soft Bake)) was performed on the hot plate at a temperature shown in Table 2 for 60 seconds to form a resist film having a thickness of 0.10 μm. Thereafter, the formed resist film was exposed through a mask pattern using an ArF excimer laser exposure apparatus (numerical aperture: 0.78) manufactured by Nikon Corporation. Thereafter, a post-exposure heat treatment (PEB) was performed for 60 seconds at the temperature shown in Table 2, followed by development with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 25 ° C. for 30 seconds. Thereafter, it was washed with water and dried to form a positive resist pattern. At this time, the exposure amount for forming a line-and-space pattern (1L1S) having a line width of 90 nm in a one-to-one line width was defined as the optimum exposure amount, and the optimum exposure amount (mJ / cm ² ) was defined as the sensitivity.

[LWR (Line Roughness Characteristics)]:
A 90 nm line and space pattern resolved at the optimum exposure for sensitivity evaluation was observed from the top of the pattern using Hitachi SEM: S9220. The line width (line width) was measured at an arbitrary point, the measurement variation was calculated as 3 sigma, and the value was taken as LWR (nm).

[DOF (depth of focus)]:
When the pattern dimension resolved with a 90 nm line-and-space pattern at the optimal exposure for the sensitivity evaluation is within ± 10% of the mask design dimension, the focus fluctuation width is DOF (nm). did.

(Synthesis Example 1):
First, 61.26 g (60 mol%) of a compound represented by the following formula (S-4) and 38.74 g (40 mol%) of a compound represented by the following formula (S-5) were converted into 200 g of 2-butanone. A monomer solution prepared by dissolving 3.58 g of 2,2′-azobis (2-methylpropionitrile) was prepared. Next, a 1000 ml three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes. After purging with nitrogen, the reactor was heated to 80 ° C. with stirring, and the monomer solution was added using a dropping funnel. The solution was added dropwise over 3 hours. The start of dropping was set as the polymerization start time, and the polymerization reaction was performed for 6 hours to obtain a polymerization solution. After completion of the polymerization, the resulting polymerization solution was cooled with water and cooled to 30 ° C. or lower, and then poured into 2000 g of methanol to precipitate a white powder. Thereafter, the precipitated white powder was filtered off. The filtered white powder was dispersed in 400 g of methanol and washed in the form of a slurry. Then, filtration operation was performed twice and it dried at 50 degreeC for 17 hours, and obtained the copolymer of the white powder (72 g, yield 72%). This copolymer has Mw of 7455 and Mw / Mn of 1.712, and as a result of ¹³ C-NMR analysis, the content ratio of repeating units derived from the compound represented by formula (S-4): formula ( The content ratio of the repeating unit represented by S-5) was 58.9: 41.1 (mol%). This copolymer is referred to as “polymer (A-1)” (polymer (A)). Of the compounds represented by the following formulas (S-1) to (S-7), the compound for constituting the repeating unit represented by the general formula (1) is represented by the formula (S-3). A compound represented by formula (S-4), and a compound represented by formula (S-6).

(Synthesis Examples 2 to 13):
Except having used the compound shown below with the compounding quantity shown below, the polymer (A-2)-(A-13) was obtained by the method similar to the synthesis example 1. Below, the content rate of the repeating unit in the obtained polymers (A-2)-(A-13), Mw, and Mw / Mn are shown below. In addition, (S-1) to (S-7) represent compounds represented by the above formulas (S-1) to (S-7), respectively. Further, for example, “polymer (A-2): (S-3) 60 / (S-5) 40 = 59.3 / 40.7 (mol%)” means that 60 mol% of the formula (S— 3) means that the polymer (A-2) was synthesized using the compound represented by 3) and 40 mol% of the compound represented by the formula (S-5). 2) contains 59.3 mol% of a repeating unit derived from the compound represented by the formula (S-3), and 40.7% of the repeating unit derived from the compound represented by the formula (S-5). It means to contain mol%.

Polymer (A-2): (S-3) 60 / (S-5) 40 = 59.3 / 40.7 (mol%), Mw = 6985, Mw / Mn = 1.632;
Polymer (A-3): (S-4) 50 / (S-5) 50 = 50.4 / 49.6 (mol%), Mw = 6450, Mw / Mn = 1.623;
Polymer (A-4): (S-4) 40 / (S-5) 60 = 41.1 / 58.9 (mol%), Mw = 6784, Mw / Mn = 1.650;
Polymer (A-5): (S-1) 15 / (S-4) 45 / (S-5) 40 / = 14.5 / 46.3 / 39.2 (mol%), Mw = 6285, Mw / Mn = 1.682;
Polymer (A-6): (S-2) 15 / (S-4) 45 / (S-5) 40 / = 14.2 / 45.1 / 40.7 (mol%), Mw = 6386, Mw / Mn = 1.721;
Polymer (A-7): (S-1) 10 / (S-4) 40 / (S-5) 50 / = 10.8 / 39.5 / 49.7 (mol%), Mw = 7163, Mw / Mn = 1.707;
Polymer (A-8) (S-2) 10 / (S-4) 40 / (S-5) 50 / = 9.7 / 41.2 / 49.1 (mol%), Mw = 6730, Mw /Mn=1.485;
Polymer (A-9) (S-6) 60 / (S-5) 40 = 60.2 / 39.8 (mol%), Mw = 6851, Mw / Mn = 1.675;
Polymer (A-10): (S-1) 25 / (S-4) 25 / (S-5) 50 / = 24.5 / 24.2 / 51.3 (mol%), Mw = 6180, Mw / Mn = 1.717;
Polymer (A-11): (S-2) 35 / (S-3) 15 / (S-5) 50 = 34.3 / 15.5 / 50.2 (mol%), Mw = 5768, Mw /Mn=1.698;
Polymer (A-12): (S-1) 25 / (S-4) 25 / (S-7) 10 / (S-5) 40 / = 24.3 / 25.1 / 9.8 / 40 .8 (mol%), Mw = 6758, Mw / Mn = 1.673;
Polymer (A-13): (S-2) 35 / (S-3) 15 / (S-7) 10 / (S-5) 50 = 36.2 / 14.9 / 10.1 / 38. 8 (mol%), Mw = 6630, Mw / Mn = 1.654

Example 1
100 parts of the polymer (A-1) obtained in Synthesis Example 1 and a radiation-sensitive acid generator (B) (shown as “acid generator” in Table 1) are represented by the following formula (B-1). 10.8 parts of a compound (ie triphenylsulfonium 2- (adamantan-1-yl) -1,1-difluoroethane-1-sulfonate, indicated as “B-1” in Table 1), and acid diffusion control 1.0 part of a compound represented by the following formula (C) as an agent (namely, 2-phenylbenzimidazole, indicated as “C” in Table 1) was mixed to obtain a raw material composition. On the other hand, as a solvent, 1900 parts of a compound represented by the following formula (D-1) (ie, propylene glycol monomethyl ether acetate, indicated as “D-1” in Table 1), represented by the following formula (D-2) 800 parts of a compound (namely, cyclohexanone, indicated as “D-2” in Table 1) and a compound represented by the following formula (D-3) (namely, γ-butyrolactone, “D— 3 ”) was mixed to prepare a mixed solvent. Then, the said raw material composition was melt | dissolved in this mixed solvent, and the radiation sensitive resin composition (composition solution) was obtained. Thereafter, the above-described various evaluations were performed using the obtained composition solution. In addition, the compounding quantity of each solvent is a mass ratio (mass part) with respect to 100 parts of polymers (A-1).

The radiation-sensitive resin composition of this example has a sensitivity evaluation result of 48.0 mJ / cm ² , LWR (line roughness characteristics) of 6.4 nm, and DOF (depth of focus) of 0.35 nm. there were.

(Examples 2 to 12, Comparative Examples 1 to 5)
Except having used the compound shown in Table 1 with the compounding quantity shown in Table 1, it carried out similarly to Example 1, and obtained the radiation sensitive resin composition of Examples 2-12 and Comparative Examples 1-5. Then, various evaluation was performed about the obtained radiation sensitive resin composition. The evaluation results are shown in Table 2.

  In Table 1, “B-2” represents a compound represented by the following formula (B-2) (that is, triphenylsulfonium perfluoro-n-butanesulfonate), and “B-3” represents 1 represents a compound represented by formula (B-3) (that is, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate), and “B-4” represents the following formula (B -4) (namely, triphenylsulfonium 2- (adamantanecarbonyloxy) -1,1,2,2-tetrafluorohexane-1-sulfonate), and “B-5” is represented by the following formula: The compound represented by (B-5) (namely, diphenyliodonium 2- (adamantan-1-yl) -1,1-difluoroethane-1-sulfonate) is shown.

  As is clear from Table 2, the radiation-sensitive resin compositions of Examples 1 to 12 have moderate sensitivity, excellent resolution performance, and diffusion compared to the radiation-sensitive resin compositions of Comparative Examples 1 to 5. It has been confirmed that the resist pattern has a property that the length is moderately short, LWR is small, and a resist pattern having a wide DOF can be formed.

  The radiation sensitive resin composition of the present invention is suitable as a material for forming a resist film used in a photolithography process using, for example, an ArF excimer laser or an electron beam as a light source.

Claims (6)

A polymer (A) having a repeating unit represented by the following general formula (1) of 40 mol% or more based on all repeating units;
A radiation-sensitive resin composition containing a radiation-sensitive acid generator (B) that generates a sulfonic acid having an alicyclic skeleton having 10 or more carbon atoms.

(In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a linear or branched alkyl group having 1 to 4 carbon atoms, and R ³ represents a carbon atom. Z represents an alicyclic skeleton having 10 or more carbon atoms.) The radiation sensitive resin composition according to claim 1, wherein the radiation sensitive acid generator (B) is a compound represented by the following general formula (2).

(In the general formula (2), R ⁴ represents a monovalent hydrocarbon group containing an alicyclic skeleton having 10 or more carbon atoms. A is represented by —O—, —COO— or —OCO—. X represents a divalent linear or branched hydrocarbon group having 1 to 20 carbon atoms in which at least a part of hydrogen atoms in the molecule may be substituted, and k represents , 0 or 1. M ⁺ represents a monovalent onium cation.) The radiation-sensitive resin composition according to claim 2, wherein the alicyclic skeleton in the R ^{4 of the} compound represented by the general formula (2) is an adamantane skeleton. The radiation sensitive resin composition according to claim 2 or 3, wherein the compound represented by the general formula (2) is a compound represented by the following general formula (2-1).

(In said general formula (2-1), each R < ⁵ > shows the C1-C8 hydrocarbon group which may be substituted mutually independently. Each R < ⁶ > may be substituted. Represents a hydrocarbon group having 1 to 8 carbon atoms, each R ⁷ represents a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms, each l independently represents an integer of 0 to 4; m represents an integer of 1 to 4, n represents an integer of 0 to 10. M ⁺ represents a monovalent onium cation.) The radiation sensitive resin composition according to any one of claims 2 to 4, wherein the M ⁺ is a sulfonium cation represented by the following general formula (3) or an iodonium cation represented by the following general formula (4). object.

(In the general formula ^{(3), R 8, R} 9, and ^{R 10} are independently of each other, linear or branched alkyl group substituted carbon atoms and optionally 1 to 10 or a substituted Or an aryl group having 6 to 18 carbon atoms, or any two of R ⁸ , R ⁹ and R ¹⁰ may be bonded to each other to form sulfur in the general formula (3). A linear structure or a branched alkyl group having 1 to 10 carbon atoms which may form a cyclic structure together with atoms and the remaining may be substituted, or an aryl group having 6 to 18 carbon atoms which may be substituted Is shown.)

(In the general formula (4), R ¹¹ and R ¹² are each independently a linear or branched alkyl group having 1 to 10 carbon atoms which may be substituted, or may be substituted. It is a good aryl group having 6 to 18 carbon atoms, or R ¹¹ and R ¹² are bonded to each other to form a cyclic structure together with the iodine atom in the general formula (4).   Z in the said General formula (1) is an adamantane skeleton, The radiation sensitive resin composition as described in any one of Claims 1-5.