JP2012128009A - Radiation-sensitive resin composition and resist pattern forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a resist coating film which increases the hydrophobicity of the coating film surface in liquid immersion exposure and also suppresses the occurrence of defects due to a development failure, and moreover has excellent lithographic performance.SOLUTION: There is provided a radiation-sensitive resin composition that contains a polymer component and includes, in the polymer component, a repeating unit (a1) represented by the following formula (1), and at least one repeating unit (f1) selected from the group consisting of repeating units represented by formula (F1-1), formula (F1-2) and formula (F1-3)

Description

  The present invention relates to a radiation-sensitive resin composition and a resist pattern forming method, and more particularly, to radiation-sensitive materials used in semiconductor manufacturing processes such as ICs, circuit boards such as liquid crystals and thermal heads, and other photolithography processes. And a method for forming a resist pattern on a resist film obtained from the composition.

  In the field of microfabrication typified by the manufacture of integrated circuit elements, a polymer having a functional group (acid-dissociable group) that is released by the action of an acid is contained in the resin composition, and the resin composition is used on the substrate. A resist film is formed on the substrate. In this case, the formed resist film is irradiated (exposed) with a short-wavelength radiation such as an excimer laser through a mask pattern, and then, if it is a positive type, the exposed portion is removed with an alkaline developer. A resist pattern is formed. At that time, a so-called chemically amplified resist in which an acid generator that generates an acid upon irradiation is contained in a resin composition and the sensitivity is improved by the action of the acid is used.

  Various types of such chemically amplified resists have been proposed in the past including polymers having an alicyclic structure such as an adamantane ring (see, for example, Patent Document 1 and Patent Document 2). Patent Document 1 discloses that an acrylic resin having a 2-alkyl-2-adamantyl group as an acid dissociable group is used as a base resin. Patent Document 2 discloses that, in the base resin, a repeating unit containing an adamantyl group having a non-leaving hydroxyl group is introduced separately from the repeating unit having an acid dissociable group. In this Patent Document 2, the configuration including the above repeating unit is intended to improve the resolution, particularly the ability to form a line and space pattern (L / S pattern).

  In recent years, as a method for forming a fine resist pattern having a line width of 45 nm or less in a chemically amplified resist, a liquid for immersion exposure (for example, pure water or a fluorine-based inert liquid) is used between a lens and a resist film. Etc.), the use of an immersion exposure method (liquid immersion lithography) in which exposure is carried out by filling is being expanded. According to this immersion exposure method, it is possible to increase the numerical aperture (NA) of the lens, and even when the NA is increased, there is an advantage that the depth of focus is not easily lowered and high resolution can be obtained. is there.

  During immersion exposure, the acid generator and other components contained in the resist film are prevented from eluting into the immersion exposure liquid, and the resist surface has good water drainage to suppress defects, It is required to enable high-speed scanning exposure. In view of this, conventionally, the surface hydrophobicity of the formed resist film has been increased by including a repeating unit having a fluorine atom in the polymer component in the resin composition. For example, in the example of Patent Document 2, a repeating unit having a group in which two trifluoromethyl groups and a hydroxyl group are bonded to one carbon atom is introduced into the base resin. In addition, in a resist for immersion exposure, a fluorine-containing polymer is contained in the resin composition separately from the base resin, and in the formed resist film, the fluorine-containing polymer is unevenly distributed on the surface of the film. It has also been carried out to increase the hydrophobicity (see, for example, Patent Document 3).

JP-A-9-73173 JP 2010-60948 A JP 2010-2870 A

  However, in a resin composition containing an adamantyl group having a non-leaving hydroxyl group in the base resin, a fluorine-containing repeating unit is introduced into the polymer component of the resin composition in order to increase the surface hydrophobicity of the resist film. In the case of the above-described Patent Document 2, it has been found that the ability to form a contact hole pattern (hereinafter also simply referred to as a hole pattern), which is one of the resolution indexes, is not so good.

  The present invention has been made in view of the above problems, and provides a radiation-sensitive resin composition capable of obtaining a resist film excellent in hole pattern forming ability, and a resist pattern forming method using the composition. Main purpose.

  As a result of intensive studies to solve the problems of the prior art as described above, as a repeating unit to be introduced into the polymer component, the repeating unit containing the adamantyl group described above, and a fluorine-containing repeating unit. It has been found that the above problem can be solved by combining a repeating unit having a specific structure, and the present invention has been completed. Specifically, the present invention provides the following radiation-sensitive resin composition and a resist pattern forming method using the composition.

According to the present invention, in the polymer component, the repeating unit (a1) represented by the following formula (1), the following formula (F1-1), the following formula (F1-2) and the following formula (F1- There is provided a radiation-sensitive resin composition having at least one repeating unit (f1) selected from the group consisting of repeating units represented by 3).
(In the formula, R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group or an alkyl group having 1 to 3 carbon atoms, and R ²⁰ is an (n + 2) -valent hydrocarbon group having 1 to 5 carbon atoms. , X is a single bond, —OCO—, —CO—NH—, —NH— or —CO—, n is an integer of 0 to 3, and m is an integer of 0 to 10. N + m ≧ 1.)
(In the formula, R ¹ represents a hydrogen atom, a fluorine atom, a trifluoromethyl group or an alkyl group having 1 to 3 carbon atoms, and X ^f1 represents the following formulas (X-1), (X-2) and (X -3).
(In the formula, R ^2a , R ^2b , R ^3a , R ^3b , R ^5a , R ^5b , R ^6a , R ^6b , R ^7a , R ^7b , R ^8a , R ^8b , R ^9a and R ^9b are each independently , A hydrogen atom, a hydroxyl group, a halogen atom, or a monovalent organic group having 1 to 15 carbon atoms, provided that four R's represented by R ^2a , R ^2b , R ^3a, and R ^3b in formula (X-1) A group consisting of six Rs of R ^5a , R ^5b , R ^6a , R ^6b , R ^7a and R ^7b in formula (X-2); R ^8a , R ^8b in formula (X-3) Any one of R in each group of R ^9a and R ^9b is bonded to an oxygen atom by elimination of one hydrogen atom of R in the above definition. Carbon atoms in which two R are bonded to each other in the group Good .R ⁴ also together form a ring structure, an alkyl group or a monovalent alicyclic hydrocarbon group having 1 to 20 carbon atoms, part of the hydrogen atoms may be substituted with a halogen atom, A part of the methylene group may be substituted with an oxygen atom or a carbonyl group.)
(In the formula, R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group or an alkyl group having 1 to 3 carbon atoms, R ^S is a divalent linking group, and R ¹² has 2 to 2 carbon atoms. 20 chained or cyclic fluorinated alkyl groups.)
(In the formula, R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms, and R ^13a and R ^13b are each independently a hydrogen atom or a carbon number of 1 to 15 carbon atoms. an alkyl group or a monovalent alicyclic hydrocarbon group. However, good .R ¹⁴ also form a ring together with the carbon atom to which the R ^13a and R ^13b is which they are attached are fluorine (It is a C1-C15 alkyl group which may have an atom, or a monovalent alicyclic hydrocarbon group, or an acid dissociable group.)

  In the composition containing the repeating unit (a1) in the polymer component of the radiation-sensitive resin composition, by using the repeating unit (f1) as a fluorine-containing repeating unit that imparts surface hydrophobicity to the resist film, Pattern forming ability can be improved in the formed resist film. In particular, when forming a hole pattern, it is possible to suppress the pattern top portion from being rounded or to be squeezed between patterns, which is excellent in that the hole pattern shape can be improved.

Moreover, according to this invention, the radiation sensitive resin composition which has at least the repeating unit represented by a following formula (F1-2-1) as said repeating unit (f1) is provided.
Wherein R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group or an alkyl group having 1 to 3 carbon atoms, R ¹⁰ is a methylene group or an oxygen atom, and R ¹¹ is a hydrogen atom, methyl A group or a trifluoromethyl group, and R ¹² is a chain or cyclic fluorinated alkyl group having 2 to 20 carbon atoms.)

The radiation sensitive resin composition of the present invention further includes a repeating unit (p1) represented by the following formula (2) and a repeating unit (L1) represented by the following formula (3) in the polymer component. You may have.
(In the formula, R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms. R ¹⁵ , R ^16, and R ¹⁷ are each independently one having 1 to 4 carbon atoms. An alkyl group or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, provided that R ¹⁶ and R ¹⁷ are a ring having 4 to 20 carbon atoms together with the carbon atoms to which they are bonded to each other; A structure may be formed.)
(In the formula, R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms, R ^L1 is a single bond or a divalent linking group, and R ^Lc is a lactone. (It is a monovalent organic group having a structure.)

  According to the present invention, there is provided a radiation-sensitive resin composition comprising, as a polymer component, a polymer (A) having the repeating unit (a1) and a polymer (B) having the repeating unit (f1). Is done. According to this configuration, the polymer (B) having the fluorine-containing repeating unit (f1) is likely to be unevenly distributed on the resist coating surface, and the surface hydrophobicity of the resist coating can be further improved. In addition, when the fluorine-containing repeating unit is the above repeating unit (f1), the shape of the top portion of the hole pattern can be improved, and a hole pattern having a favorable shape can be obtained with less resistance to gaps between the patterns. it can.

  According to the present invention, using the above-described radiation-sensitive resin composition, a step of forming a resist film on a substrate, an immersion exposure liquid is disposed on the resist film, and the immersion exposure liquid is interposed therebetween. There is provided a resist pattern forming method including a step of exposing the resist film and a step of developing the resist film to form a resist pattern after the exposure.

  According to the resist pattern forming method of the present invention, since the resist pattern is formed on the resist film formed using the radiation-sensitive resin composition already described, the shape of the hole pattern can be improved.

  In the present specification, the term “hydrocarbon group” includes a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. This “hydrocarbon group” may be a saturated hydrocarbon group or an unsaturated hydrocarbon group.

In addition, the “chain hydrocarbon group” means a hydrocarbon group that does not include a cyclic structure in the main chain and is composed only of a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. Shall be included. The “alicyclic hydrocarbon group” means a hydrocarbon group that includes only an alicyclic hydrocarbon structure as a ring structure and does not include an aromatic ring structure. However, it is not necessary to be constituted only by the structure of the alicyclic hydrocarbon, and a part thereof may include a chain structure. “Aromatic hydrocarbon group” means a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessary to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic hydrocarbon structure.
“(Meth) acryl” means to include both “acryl” and “methacryl”.

The figure which shows the specific example of a hole pattern. (A) is a case where a pattern shape is favorable, and (b)-(d) is a case where a shape is defective.

  The radiation-sensitive resin composition of the present invention contains a polymer component, and a repeating unit (a1) containing a non-leaving hydroxyl group and an adamantyl group as at least a part of all repeating units of the polymer component. And a repeating unit (f1) having a fluorine atom. Further, the present composition may contain an acid generator (C) as a suitable optional component, and further, as other optional components, an acid diffusion inhibitor (D), a solvent (E) and an additive (F ) And the like. Hereinafter, each component will be described in order.

<Polymer component>
[Repeating unit (a1)]
The repeating unit (a1) contained in the polymer component in the present invention can be represented by the following formula (1).
(In the formula, R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group or an alkyl group having 1 to 3 carbon atoms, and R ²⁰ is an (n + 2) -valent hydrocarbon group having 1 to 5 carbon atoms. , X is a single bond, —OCO—, —CO—NH—, —NH— or —CO—, n is an integer of 0 to 3, and m is an integer of 0 to 10. N + m ≧ 1.)

In the above formula (1), the alkyl group having 1 to 3 carbon atoms of R ¹ may be linear or branched, and specifically includes a methyl group, an ethyl group, and n-propyl. Group and isopropyl group. R ¹ is preferably a methyl group.

The (n + 2) -valent hydrocarbon group having 1 to 5 carbon atoms in R ²⁰ may be a chain hydrocarbon group or an alicyclic hydrocarbon group. The chain hydrocarbon group may be linear or branched. Specifically, for example, methane, ethane, propane, butane, 2-methylpropane, 1-butene, pentane, And groups obtained by removing (n + 2) hydrogen atoms from a chain hydrocarbon such as 1-pentene, 2-methylbutane, and 2,2-dimethylpropane. Examples of the alicyclic hydrocarbon group include groups obtained by removing (n + 2) hydrogen atoms from an alicyclic hydrocarbon such as cyclopropane, cyclobutane, and cyclopentane.
Of these, R ²⁰ is preferably a chain hydrocarbon group. Further, the number of carbon atoms constituting R ²⁰ is preferably 1 to 4, more preferably 1 or 2.

The number n of hydroxyl groups bonded to R ²⁰ is an integer of 0 to 3, preferably an integer of 0 to 2, and more preferably 0 or 1. In addition, when n is an integer of 1-3, the carbon atom which a hydroxyl group couple | bonds is not specifically limited.

X in the above formula (1) is a single bond, —OCO—, —CO—NH—, —NH— or —CO—. Any of the two bonds in the divalent group in X may be bonded to R ²⁰ in the above formula (1). X is preferably a single bond.
m is an integer of 0 to 10, preferably an integer of 0 to 4, and more preferably an integer of 0 to 2. However, the relationship of n + m ≧ 1 is satisfied. When m is an integer of 1 to 10, the carbon atom to which the hydroxyl group is bonded is not particularly limited, but is preferably a tertiary carbon atom of an adamantane ring. More preferably, the carbon atom to which the hydroxyl group is bonded is a carbon atom at the bridge head position of the adamantane ring or a carbon atom bonded to X in the formula (1).
Among them, the repeating unit (a1) is preferably a repeating unit in which n is 0 in the above formula (1), that is, a unit represented by the following formula (1x).
^{(Wherein, R 20a} is an alkanediyl group having 1 to 5 carbon atoms, _{m a} is a is .R ¹ and X is an integer of from 1 to 10, respectively the equation (1) synonymous.)

Specific examples of R ^20a in the above formula (1x) include methylene group, ethylene group, propylene group such as 1,3-propylene group and 1,2-propylene group, butylene group, pentamethylene group, hexamethylene group and the like. Can be mentioned. R ^20a is preferably a methylene group.
m _a is an integer of 1 to 10, preferably an integer of 1 to 3, and more preferably 1 or 2. As a preferred specific example of the carbon atom to which the hydroxyl group is bonded, the description in the above formula (1) can be applied as it is.

Specific examples of the repeating unit (a1) include those represented by the following formula.
(In the formula, R ¹ has the same meaning as the above formula (1x).)

  Examples of the monomer that gives the repeating unit (a1) include, for example, International Publication No. 2010/071103, International Publication No. 2009/063829, International Publication No. 2008/050796, International Publication No. 2005/108343. It can be synthesized by the method described.

[Polymer (A)]
The repeating unit (a1) is contained in at least one polymer among the polymer components. In the polymer having the repeating unit (a1) (hereinafter referred to as polymer (A)), the content ratio of the repeating unit (a1) is when the total amount of the repeating unit of the polymer (A) is 100 mol%. 5 to 50 mol% is preferable, and 10 to 30 mol% is more preferable. By setting it as the above range, MEEF (Mask Error Enhancement Factor) which is an index of fidelity to the mask can be further reduced in the formed resist pattern, and a resist pattern having a better shape can be obtained. In addition, the polymer (A) may have only 1 type illustrated above as a repeating unit (a1), and may have 2 or more types.

  The polymer (A) may have a repeating unit other than the repeating unit (a1). Specific examples of the repeating unit include a repeating unit (p1) having an acid dissociable group, a repeating unit (L1) having a lactone structure, and a repeating unit (f1) having a fluorine atom.

[Repeating unit (p1)]
Examples of the repeating unit (p1) that the polymer (A) may have include a repeating unit represented by the following formula (2).
(Wherein R ¹⁵ , R ¹⁶ and R ¹⁷ are each independently an alkyl group having 1 to 4 carbon atoms or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, provided that R ¹⁶ and R ¹⁷ may be bonded to each other to form a ring structure having 4 to 20 carbon atoms together with the carbon atoms to which each is bonded, and R ¹ has the same meaning as in the above formula (1).

In said formula (2), as a C1-C4 alkyl group in R <^15> , R < ¹⁶ > and R < ¹⁷ >, a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group Etc. Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms include a monocyclic saturated or unsaturated alicyclic hydrocarbon group such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclopentenyl group, and a cyclohexenyl group. A monocyclic alicyclic hydrocarbon group to which a chain structure such as a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, or a cyclohexylbutyl group is bonded; bicyclo [2.2.1 ] Heptyl group, bicyclo [2.2.2] octyl group, tricyclo [5.2.1.0 ^2,6 ] decyl group, adamantyl group, tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] polycyclic alicyclic hydrocarbon groups such as dodecyl group.

Examples of the ring having 4 to 20 carbon atoms formed by the bond of R ¹⁶ and R ¹⁷ include cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane. , Tricyclo [5.2.1.0 ^2,6 ] decane, adamantane, tetracyclo [4.4.0.1 ^2,5 . Examples include alicyclic hydrocarbons such as 1 ^7,10 ] dodecane, and may include condensed rings containing these. In these alicyclic hydrocarbons, at least one of the hydrogen atoms may be substituted with a group exemplified as a substituent in the description of R ^{2a to} R ^9b above.

As —CR ¹⁵ R ¹⁶ R ¹⁷ in the above formula (2), a tert-butyl group is preferable in terms of easy synthesis, and a cycloalkane skeleton or an organic compound is preferable in that the shape of the resist pattern after development can be further improved. Groups having a bridge skeleton are preferred. Preferable specific examples of the group having a cycloalkane skeleton or a bridged skeleton include groups represented by the following formulas (p1-1) to (p1-6).
(In the formula, r is an integer of 0 to 8. “*” represents a bond bonded to an oxygen atom in the above formula (2). R ¹⁵ , R ¹⁶ and R ¹⁷ represent the above formula (2). Is synonymous with

  The content ratio of the repeating unit (p1) in the polymer (A) is preferably 15 to 85 mol%, more preferably 25 to 75 mol%, when the total amount of the repeating units in the polymer (A) is 100 mol%. Preferably, 35-60 mol% is more preferable. By setting it as the said range, the contrast of an exposed part and an unexposed part becomes still better, and it is effective for improvement of MEEF. In addition, the adhesion to the substrate is further improved. In addition, a polymer (A) may have a repeating unit (p1) individually by 1 type or in combination of 2 or more types.

[Repeating unit (L1)]
As a repeating unit (L1) which a polymer (A) may have, the repeating unit represented by following formula (3) can be mentioned, for example.
(In the formula, R ^L1 is a single bond or a divalent linking group, and R ^Lc is a monovalent organic group having a lactone structure. R ¹ has the same meaning as in the above formula (1).)

As a bivalent coupling group of ^RL1 in the said Formula (3), a C1-C20 bivalent hydrocarbon group can be mentioned, for example. In the hydrocarbon group, at least one methylene group is an oxygen atom, a sulfur atom, —NR′— (where R ′ is a hydrogen atom or a monovalent organic group), a carbonyl group, —CO. It may be substituted with —O— or —CO—NH—, and at least one hydrogen atom bonded to a carbon atom may be substituted with a halogen atom such as a fluorine atom. Specific examples of the divalent hydrocarbon group in R ^L1 include one hydrogen atom included in the alkyl group and monovalent alicyclic hydrocarbon group exemplified as R ^{15 to} R ¹⁷ in the above formula (2). Examples thereof include a group obtained by removing two hydrogen atoms from a removed group or an aromatic ring such as a benzene ring or a naphthalene ring.
Among these, R ^L1 is preferably a single bond, an alkanediyl group having 1 to 4 carbon atoms, or a group in which at least one methylene group of the alkanediyl group is substituted with a carbonyl group. , —CH ₂ CO— or —C (CH ₃ ) ₂ CO— is more preferable.

Examples of ^RLc in the above formula (3) include those represented by the following formulas (Lc-1) to (Lc-6).
(In the formula, R ^L2 is each independently an oxygen atom or a methylene group, and R ^L3 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. K ₁ is independently 0 or 1. And k ₂ is an integer of 0 to 3. “*” represents a bond bonded to R ^L1 in the above formula (3), provided that the formulas (Lc-1) to (Lc-6). The group represented by may have a substituent.)

In the above formulas (Lc-1) to (Lc-6), as the alkyl group having 1 to 4 carbon atoms in R ^L3 , specific examples given in the description of R ^{15 to} R ^{17 in} the above formula (1) can be applied. . R ^L3 is preferably a methyl group.
Examples of the substituent that the groups represented by the above formulas (Lc-1) to (Lc-6) may have include, for example, an alkyl group having 1 to 10 carbon atoms and a monovalent fat having 3 to 20 carbon atoms. Examples thereof include a cyclic hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms. In these substituents, for example, at least one hydrogen atom of the above alkyl group or the like may be substituted with a fluorine atom, a hydroxyl group, a cyano group, a carboxyl group, or the like, and at least one methylene group may be —O. It may be substituted with —, —CO—, —COO—, —OCO— or the like.

Specific examples of the repeating unit (L1) include those described in paragraphs [0054] to [0057] of JP2007-304537A and those described in paragraphs [0086] to [0088] of JP2008-088343A. And those represented by the following formulas (9-1a) to (9-1j).
(In the formula, R has the same meaning as R ^{1 in the} above formula (3).)

  In the above polymer (A), the content ratio of the repeating unit (L1) is preferably 10 to 50 mol%, preferably 20 to 40 mol, when the total amount of the repeating units constituting the polymer (A) is 100 mol%. Mole% is more preferable. By setting it as the above range, the affinity for the developer can be improved. Moreover, the pattern excellent in adhesiveness with a board | substrate can be formed. In addition, a polymer (A) may have a repeating unit (L1) individually by 1 type or in combination of 2 or more types.

[Repeating unit (f1)]
The repeating unit (f1) contained in the polymer component in the present invention may be contained in the polymer (A). Specific examples of the repeating unit (f1) include the following repeating units (f1-1) to (f1-3).

1. Repeating unit (f1-1)
The repeating unit (f1-1) is represented by the following formula (F1-1).
^{(Wherein, X f1} is represented by the following formula (X-1) is a structure represented by (X-2) or (X-3) .R ¹ is as defined in the above formula (1).)
(In the formula, R ^2a , R ^2b , R ^3a , R ^3b , R ^5a , R ^5b , R ^6a , R ^6b , R ^7a , R ^7b , R ^8a , R ^8b , R ^9a and R ^9b are each independently , A hydrogen atom, a hydroxyl group, a halogen atom, or a monovalent organic group having 1 to 15 carbon atoms, provided that four R's represented by R ^2a , R ^2b , R ^3a, and R ^3b in formula (X-1) A group consisting of six Rs of R ^5a , R ^5b , R ^6a , R ^6b , R ^7a and R ^7b in formula (X-2); R ^8a , R ^8b in formula (X-3) Any one of R in each group of R ^9a and R ^9b is bonded to an oxygen atom by elimination of one hydrogen atom of R in the above definition. Carbon atoms in which two R are bonded to each other in the group Good .R ⁴ also together form a ring structure, an alkyl group or a monovalent alicyclic hydrocarbon group having 1 to 20 carbon atoms, part of the hydrogen atoms may be substituted with a halogen atom, (Part of the methylene group of R ⁴ may be substituted with an oxygen atom or a carbonyl group.)

In the above formulas (X-1) to (X-3), examples of the monovalent organic group having 1 to 15 carbon atoms of R ^{2a to} R ^9b include those exemplified as R ^{15 in the} above formula (2), etc. Alkyl groups and monovalent alicyclic hydrocarbon groups as described above; alkoxy groups such as methoxy groups and ethoxy groups; acyloxy groups such as formyloxy groups and acetoxy groups; phenyl groups, tolyl groups, naphthyl groups, anthryl groups, phenanthryls Aryl groups such as a group; aralkyl groups such as a benzyl group, a diphenylmethyl group, and a phenethyl group;

  In these, at least one of hydrogen atoms bonded to a carbon atom may be substituted. Examples of the substituent in this case include a halogen atom such as a fluorine atom or a chlorine atom, a hydroxyl group, a cyano group, an oxo group, an alkyl group optionally having a fluorine atom, an aryl group, an alkoxy group, an alkoxycarbonyl group, An alkoxyalkyl group, an acyloxy group, an acyloxyalkyl group, an alkoxyalkoxy group, etc. can be mentioned. Among these, a hydrogen atom, a hydroxyl group, a halogen atom, a methyl group, an ethyl group, a propyl group, a tert-butyl group, and a perfluoroalkyl group are preferable among these. In the hydrocarbon group exemplified above, at least one of the methylene groups of the carbon hydrogen group is, for example, an oxygen atom, a sulfur atom, —NR′— (where R ′ is a hydrogen atom or a monovalent organic group). And may be substituted with a carbonyl group, —CO—O— or —CO—NH—.

However, in the above formulas (X-1) to (X-3), one of R ^2a , R ^2b , R ^3a and R ^3b R, R ^5a , R ^5b , R ^6a , R ^6b , R ^7a and R in one of R ^7b and R in one of R ^8a , R ^8b , R ^9a and R ^9b are separated from each other by formula (X-1) to It is bonded to the oxygen atom in (X-3). The R bonded to the oxygen atom is, for example, a single bond, an oxy group, or two hydrogen atoms removed from the group exemplified as the monovalent organic group having 1 to 15 carbon atoms in R ^{2a to} R ^9b above. Valent groups.

R ^2a , R ^2b , R ^3a and R ^3b in formula (X-1) may be combined in any combination, and two of them may be bonded together to form a ring together with the carbon atom to which they are bonded. . In this case, examples of the ring formed include alicyclic hydrocarbons having 3 to 12 carbon atoms. Specifically, for example, the ring is formed by the bond of R ¹⁶ and R ^{17 in} the above formula (2). What was illustrated as a ring, a cyclopropane, etc. can be mentioned. Moreover, the condensed ring containing these may be sufficient. In these alicyclic hydrocarbons, at least one of the hydrogen atoms may be substituted with a group exemplified as a substituent in the description of R ^{2a to} R ^9b above.

R ^5a , R ^5b , R ^6a , R ^6b , R ^7a and R ^{7b in} formula (X-2) are also bonded to each other to form a ring with the carbon atom to which they are bonded. Also good. Similarly, R ^8a , R ^8b , R ^9a and R ^9b in formula (X-3) may be combined with each other to form a ring with the carbon atom to which they are bonded. . As the ring formed, for example, those exemplified as the ring formed by binding of R ¹⁶ and R ¹⁷ in the formula (2) include a cyclopropane, and the like.

Specific examples of the alkyl group having 1 to 20 carbon atoms and the monovalent alicyclic hydrocarbon group of R ⁴ are the alkyl group and monovalent alicyclic hydrocarbon group exemplified in the above R ^{2a to} R ^9b , respectively. Etc. As R ⁴ , a part of the methylene group of the alkyl group or monovalent alicyclic hydrocarbon group may be substituted with an oxygen atom or a carbonyl group. The hydrogen atom may have at least one hydrogen atom substituted with a halogen atom, preferably a fluorine atom.

R ⁴ is preferably one in which a part of the methylene group of the alkyl group having 1 to 20 carbon atoms or the monovalent alicyclic hydrocarbon group is substituted with an oxygen atom or a carbonyl group. Specifically, as the formulas (X-1) to (X-3) having such R ⁴ , the following formulas (X1-1) to (X1-3) and (X2-1) to (X2-3) The thing represented by is mentioned.
(In the formula, R ^4a is a hydrogen atom, an alkyl group having 1 to 19 carbon atoms or a monovalent alicyclic hydrocarbon group, and a part of the hydrogen atoms in the alkyl group and alicyclic hydrocarbon group are halogenated. An atom or a part of a methylene group may be substituted with an oxygen atom or a carbonyl group, R ^2a , R ^2b , R ^3a , R ^3b , R ^5a , R ^5b , R ^6a , R ^6b , R ^<7a> , R ^<7b> , R ^<8a> , R ^<8b> , R ^<9a> and R ^<9b> are synonymous with the above formulas (X-1) to (X-3).
(In the formula, R ^4b is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or a monovalent alicyclic hydrocarbon group, and a part of the hydrogen atoms in the alkyl group and alicyclic hydrocarbon group are halogenated. An atom may be substituted, and a part of the methylene group may be substituted with an oxygen atom or a carbonyl group, and R ^4c is an alkyl group having 1 to 19 carbon atoms or a monovalent alicyclic hydrocarbon group. may some of the hydrogen atoms in the alkyl group and the alicyclic hydrocarbon group is substituted with a halogen atom, a part of the methylene groups may be replaced by an oxygen atom or a carbonyl group. these R ^4b and R ^4c may be bonded to each other to form a ring structure together with the carbon atom and the oxygen atom to which these are bonded, R ^2a , R ^2b , R ^3a , R ^3b , R ^5a , R ^5b , R ^6a , R ^6b , R ^7a , R ^7b , R ^8a , ^R8b , ^R9a and ^R9b have the same ^{meanings as those} in the above formulas (X-1) to (X-3).)

R ^{4a in} the above formulas (X1-1) to (X1-3), R ^{4b in} the above formulas (X2-1) to (X2-3), an alkyl group in R ^4c and a monovalent alicyclic hydrocarbon group Specific examples of these include, for example, the same examples as the specific examples of the alkyl group and alicyclic hydrocarbon group of R ^{2a to} R ^9b described above. In the group, at least one hydrogen atom may be substituted with a halogen atom, preferably a fluorine atom, and at least one methylene group may be substituted with an oxygen atom or a carbonyl group.

R ^{4a in} this case is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group, more preferably a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, A fluoromethyl group;
R ^4b is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and more preferably a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group.
R ^4c is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a cycloalkyl group having 3 to 10 carbon atoms, and more preferably a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, or a cyclohexyl group. .
R ^4b and R ^4c may be bonded to each other to form a ring structure together with the carbon atom and oxygen atom to which they are bonded. Examples of the ring structure in this case include a tetrahydrofuran ring, a methyltetrahydrofuran ring, a methoxytetrahydrofuran ring, a tetrahydropyran ring, a methyltetrahydropyran ring, a methoxytetrahydropyran ring, and a 1,4-dioxane ring.

Specific examples of the repeating unit (f1-1) include the following.
(In the formula, R ¹ has the same meaning as the above formula (1).)

2. Repeating unit (f1-2)
The repeating unit (f1-2) can be represented by the following formula (F1-2).
(Wherein R ^S is a divalent linking group, R ¹² is a chain or cyclic fluorinated alkyl group having 2 to 20 carbon atoms. R ¹ has the same meaning as in the above formula (1). is there.)

In the formula (F1-2), examples of the divalent linking group for R ^S include the same divalent linking groups as those exemplified as R ^L1 for the formula (L-1). In addition, R ^S may have a lactone structure. Examples of the lactone structure include a divalent group obtained by removing two hydrogen atoms from the same or different carbon atoms in a lactone compound represented by the following formula. Each lactone compound represented by the following formula may have a substituent.

In the above formula (F1-2), examples of the linear or cyclic fluorinated alkyl group having 2 to 20 carbon atoms of R ¹² include 2,2,2-trifluoroethyl group, 3,3,3-trimethyl, and the like. Fluoropropyl group, 1H, 1H, 3H-tetrafluoropropyl group, 1,1,1,3,3,3-hexafluoroisopropyl group, 1H, 1H, 5H-octafluoropentyl group, 1H, 1H, 7H-dodeca Fluoroheptyl group, 2- (perfluorobutyl) ethyl group, 2- (perfluorohexyl) ethyl group, 2- (perfluorooctyl) ethyl group, 2- (perfluorodecyl) ethyl group, perfluorocyclohexyl group, perfluoro Examples thereof include a cyclohexyl group. However, it is not limited to these.

In the above formula (F1-2), R ^S is preferably a divalent group having an alkanediyl group or a lactone structure, and specifically, the following formula (F1-2-1) or the following formula (F1- The repeating unit represented by 2-2) is preferable.
(In the formula, R ¹⁰ is a methylene group or an oxygen atom, R ¹¹ is a hydrogen atom, a methyl group or a trifluoromethyl group. R is an integer of 1 to 6. R ¹ and R ¹² are And each has the same meaning as the above formula (F1-2).)

In the above formula (F1-2-1), the bonding positions of R ¹¹ and —CO—O—R ¹² are not particularly limited. Moreover, as for r in the said Formula (F1-2-2), 1-3 are preferable.
As the repeating unit (f1-2), those represented by the above (F1-2-1) are preferable, and the following formula (F1-2-1a) or the following formula (F1-2-1b) is particularly preferable. The thing represented by these is preferable.
(In the formula, R ¹ , R ¹⁰ , R ¹¹ , and R ¹² are respectively synonymous with the above formula (F1-2-1).)

Specific examples of the repeating unit (f1-2) include the following.
(In the formula, R ¹ has the same meaning as the above formula (1).)

  In addition, about the monomer which gives the repeating unit represented by the said formula (F1-2-1), it is compoundable by the method as described in Unexamined-Japanese-Patent No. 2008-111103, for example.

3. Repeating unit (f1-3)
The repeating unit (f1-3) can be represented by the following formula (F1-3).
(Wherein R ^13a and R ^13b are each independently a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or a monovalent alicyclic hydrocarbon group, provided that R ^13a and R ^13b are It may combine to form a ring structure together with the carbon atoms to which these are bonded, and R ¹⁴ is an alkyl group having 1 to 15 carbon atoms or a monovalent alicyclic hydrocarbon group which may have a fluorine atom. Or R ¹ is synonymous with the above formula (1).

In the above formula (F1-3), examples of the alkyl group having 1 to 15 carbon atoms or the monovalent alicyclic hydrocarbon group of R ^13a , R ^13b, and R ¹⁴ include, for example, the above formulas (X-1) to ( The same thing as the specific example of the alkyl group and alicyclic hydrocarbon group in R ^{< 2a} > -R <^9b> of X-3) is mentioned. R ^13a and R ^13b may be bonded to each other to form a ring structure together with the carbon atom to which they are bonded. Examples of the ring formed, for example, those exemplified as the ring formed by binding of R ¹⁶ and R ¹⁷ in the formula (2) include a cyclopropane, and the like.

When R ¹⁴ has a fluorine atom, examples of the fluorinated alkyl group include a group in which part or all of the hydrogen atoms of the above alkyl group or monovalent alicyclic hydrocarbon group are substituted with a fluorine atom. Can do. Specifically, in addition to those similar to the illustration of R ¹² in the formula (F1-2), trifluoromethyl group and the like.

R ¹⁴ may be an acid dissociable group. Here, the acid-dissociable group is a group that substitutes a hydrogen atom of a polar group such as a hydroxyl group or a carboxyl group, and is a group that is eliminated by the action of an acid. Although not particularly limited acid dissociable group for R ^14, for example, other specific examples of ^-CR 15 ^R 16 ^{R 17} in the formula (2), t-butoxycarbonyl group, tetrahydropyranyl group, tetrahydrofuranyl group, Examples include (thiotetrahydropyranylsulfanyl) methyl group, (thiotetrahydrofuranylsulfanyl) methyl group, alkoxy-substituted alkyl groups such as alkoxy-substituted methyl groups and alkoxy-substituted isobutyl groups, alkylsulfanyl-substituted methyl groups, and alkoxycarbonyl-substituted alkyl groups. Can do. In addition, as an alkoxyl group (substituent) in an alkoxy substituted methyl group, a C1-C4 alkoxyl group is mentioned, for example. Moreover, as an alkyl group (substituent) in an alkylsulfanyl substituted methyl group, a C1-C4 alkyl group is mentioned, for example. Examples of the alkoxycarbonyl group (substituent) in the alkoxycarbonyl-substituted alkyl group include an alkoxycarbonyl group having 1 to 4 carbon atoms.

Specific examples of the repeating unit (f1-3) include the following.
(In the formula, R ¹ has the same meaning as the above formula (1).)

  The repeating unit (f1-3) may be contained alone as the repeating unit (f1) in the polymer (A), but the repeating unit (f1-1) and the repeating unit (f1) -2) is preferably contained together with at least one of the above.

  In the polymer (A), the content of the repeating unit (f1) is preferably 1 to 50 mol%, preferably 5 to 30 when the total amount of the repeating units constituting the polymer (A) is 100 mol%. Mole% is more preferable. By setting it as the above range, the surface hydrophobicity of the formed resist film can be suitably increased, and also when forming the hole pattern, the cross-sectional shape of the resist pattern can be made closer to a rectangle. . In addition, a polymer (A) may have a repeating unit (f1) individually by 1 type or in combination of 2 or more types. When having two or more types of repeating units (f1), they may have two or more types selected from the same repeating units among the repeating units (f1-1) to (f1-3), or different repeating units. You may have 2 or more types chosen from these. When the polymer (A) contains the repeating unit (f1), the polymer (A) has at least the repeating unit represented by (F1-2-1) as the repeating unit (f1). preferable.

  When the polymer (A) has the repeating unit (a1), the repeating unit (p1) and the repeating unit (f1), and if necessary, the repeating unit (L1), the polymer (A) is used as a base. The radiation sensitive resin composition contained as resin can be obtained. On the other hand, the repeating unit (f1) may be contained in the polymer (A) having the repeating unit (a1), but the polymer component in the present composition is different from the polymer (A). In the structure containing the union (B), the polymer (B) preferably has. The radiation sensitive resin composition containing such a polymer (A) and a polymer (B) can be used particularly suitably for immersion.

[Polymer (B)]
The content ratio of the repeating unit (f1) contained in the polymer (B) is preferably 10 to 100 mol% when the total amount of the repeating units constituting the polymer (B) is 100 mol%, and is preferably 20 to 100 mol%. Mole% is more preferable. By setting it as the said range, while being able to improve the surface hydrophobicity of the formed resist film more, the gap between holes after alkali image development can be suppressed more appropriately at the time of formation of a hole pattern. In addition, a polymer (B) may have a repeating unit (f1) individually by 1 type or in combination of 2 or more types. However, the polymer (B) preferably has at least a repeating unit represented by the above (F1-2-1) as the repeating unit (f1).

  The polymer (B) preferably has a higher fluorine atom content than the polymer (A). By doing so, in the formed resist film, the polymer (B) is easily unevenly distributed on the surface layer of the film, and the surface hydrophobicity of the resist film is easily developed. On the other hand, the polymer (A) is likely to be localized on the substrate side, and when forming the hole pattern, the gap between the holes can be suitably suppressed.

The fluorine atom content in the polymer (B) is preferably 5% by mass, more preferably 5 to 50% by mass, even more preferably 5%, when the entire polymer (B) is 100% by mass. -40 mass%. The fluorine atom content can be measured by ¹³ C-NMR.

  In the polymer component in the present invention, the content of the polymer (B) is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the polymer (A). And particularly preferably 1 to 7.5 parts by mass. By setting the content of the polymer (B) in the above range, the effect of containing the polymer (B), that is, the surface hydrophobicity of the formed resist film can be appropriately increased, and development defects can be suitably suppressed. .

[Other repeating units that may be contained in the polymer component]
The polymer (A) and the polymer (B) contained as necessary may have other repeating units different from the repeating units exemplified above. Examples of such other repeating units include fluorine atom-containing repeating units described in paragraphs [0038] to [0075] of Japanese Patent Application No. 2010-223972, and paragraphs [0081] to [0084] of the same publication. The repeating unit having an alkali-soluble group described in the above, the repeating unit having a cyclic carbonate structure described in the paragraphs [0091] to [0095] of the same publication, and the paragraphs [0043] to [0046] of the Japanese Patent Application No. 2010-162195. And the repeating unit derived from the aromatic compound described in paragraph [0051] of the same publication. These other repeating units may be contained in polymers other than the polymer (A) and the polymer (B).

  In particular, when the polymer (B) is included as a polymer component in the present radiation sensitive resin composition, the repeating unit (L1) or the repeating unit may be included as the repeating unit that the polymer (B) may have. In addition to (p1), there can be mentioned fluorine atom-containing repeating units exemplified as the above other repeating units, repeating units having an alkali-soluble group, repeating units having a cyclic carbonate structure, and the like. By incorporating the repeating unit (L1), the repeating unit (p1) or the like into the polymer (B), the solubility of the exposed portion in the development process can be improved, and the pattern forming ability can be improved. Is preferred.

[Molecular weight of polymer]
The weight average molecular weight (hereinafter referred to as “Mw”) in terms of standard polystyrene by gel permeation chromatography (GPC) of the polymer (A) is preferably 1,000 to 100,000, more preferably 1, 000 to 30,000, more preferably 1,000 to 20,000. By making Mw of a polymer (A) into the said range, in the formed resist film, heat resistance and developability will become further excellent. The ratio (Mw / Mn) of Mw of the polymer (A) and the number average molecular weight (hereinafter referred to as “Mn”) by GPC method is usually 1 to 5, preferably 1 to 3. is there. In the said polymer (A), when Mw is 1,000-100,000 and Mw / Mn is 1-5, the radiation sensitive resin composition suitable for formation of a finer resist pattern is obtained. Can do.

  The Mw of the polymer (B) is preferably 1,000 to 50,000, more preferably 1,000 to 40,000, still more preferably 1,000 to 30,000. By setting Mw of the polymer (B) in the above range, a resist film having a sufficient receding contact angle can be formed, and the developability is excellent. Moreover, the ratio (Mw / Mn) of Mw and Mn of the polymer (B) is preferably 1 to 5, more preferably 1 to 4.

[Method for producing polymer]
The polymer (A) and the polymer (B) contained as necessary can be synthesized according to a conventional method such as radical polymerization. For example, (1) a method in which a solution containing a monomer and a radical initiator is dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction; (2) a solution containing the monomer and radical initiation A method in which a solution containing an agent is separately dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction; (3) a plurality of types of solutions containing each monomer, and a radical initiator It is preferable to synthesize | combine by the method of dripping the solution containing each separately to the solution containing a reaction solvent or a monomer, and carrying out a polymerization reaction;

  What is necessary is just to determine the reaction temperature in these methods suitably with initiator seed | species. Usually, it is 30-150 degreeC, 40-150 degreeC is preferable and 50-140 degreeC is still more preferable. Although dripping time changes with conditions, such as reaction temperature, the kind of initiator, and the monomer made to react, 30 minutes-8 hours are preferable and 1-6 hours are more preferable. Further, the total reaction time including the dropping time varies depending on the conditions similarly to the dropping time, but is usually 30 minutes to 12 hours, preferably 45 minutes to 12 hours, and more preferably 1 to 10 hours.

  Examples of the radical initiator used in the polymerization include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2 -Cyclopropylpropionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), azo radical initiators such as dimethyl 2,2′-azobis (2-methylpropionate); benzoyl peroxide And peroxide radical initiators such as t-butyl hydroperoxide and cumene hydroperoxide. Moreover, these radical initiators can be used individually or in mixture of 2 or more types.

  As the polymerization solvent, any solvent other than a solvent that inhibits polymerization (nitrobenzene having a polymerization inhibiting effect, mercapto compound having a chain transfer effect, etc.) and capable of dissolving the monomer may be used. it can. Examples thereof include alcohols, ethers, ketones, amides, esters / lactones, nitriles, and mixed solvents thereof. These solvents can be used alone or in admixture of two or more.

  The polymer obtained by the polymerization reaction is preferably recovered by a reprecipitation method. That is, after the polymerization reaction is completed, the polymer is recovered as a powder by introducing the polymerization solution into a reprecipitation solvent. As the reprecipitation solvent, alcohols or alkanes can be used alone or in admixture of two or more. In addition to the reprecipitation method, the polymer can be recovered by removing low molecular components such as monomers and oligomers by a liquid separation operation, a column operation, an ultrafiltration operation, or the like.

<Acid generator (C)>
Examples of the acid generator (C) constituting the radiation-sensitive resin composition of the present invention include onium salt compounds such as sulfonium salts and iodonium salts, sulfone compounds such as organic halogen compounds, disulfones and diazomethane sulfones. it can. The content of the acid generator (C) in the radiation-sensitive resin composition is the form of the acid generator that is a compound as described later, and other heavy materials such as the polymer (A) and the polymer (B). It may be in the form of an acid generating group incorporated as part of the coalescence or both forms.

  Preferable specific examples of such an acid generator (C) include, for example, compounds described in paragraphs [0080] to [0113] of JP-A-2009-134088.

  Specific examples of the acid generator (C) include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, and bis (4-t-butylphenyl) iodonium. Trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium Nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, cyclohexyl 2-oxocyclohexyl Le methyl trifluoromethanesulfonate, dicyclohexyl-2-oxo-cyclohexyl trifluoromethane sulfonate, 2-oxo-cyclohexyl dimethyl sulfonium trifluoromethane sulfonate, 4-hydroxy-1-naphthyl dimethyl sulfonium trifluoromethane sulfonate,

  4-hydroxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-hydroxy-1-naphthyltetrahydrothiophenium nonafluoro-n-butanesulfonate, 4-hydroxy-1-naphthyltetrahydrothiophenium perfluoro-n- Octanesulfonate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (1-naphthylacetomethyl) Tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- 3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro -n- butane sulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro -n- octane sulfonate,

  Trifluoromethanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, nonafluoro-n-butanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide , Perfluoro-n-octanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, N-hydroxysuccinimide trifluoromethanesulfonate, N-hydroxysuccinimide nonafluoro-n- Preferred are butane sulfonate, N-hydroxysuccinimide perfluoro-n-octane sulfonate, 1,8-naphthalenedicarboxylic imide trifluoromethane sulfonate, triphenylsulfonium 1,1-difluoro-2-adamantyl ethane sulfonate.

  An acid generator (C) can be used individually or in mixture of 2 or more types. The compounding amount of the acid generator (C) is 0.1 to 30 with respect to 100 parts by mass of the total amount of the polymer contained in the radiation-sensitive resin composition from the viewpoint of ensuring the sensitivity and developability as a resist. It is preferable that it is a mass part, and it is further more preferable that it is 0.1-20 mass parts. In this case, when the compounding amount of the acid generator is less than 0.1 parts by mass, the sensitivity and developability tend to be lowered. On the other hand, when it exceeds 30 parts by mass, the transparency to radiation is lowered and a rectangular resist is produced. It tends to be difficult to obtain a pattern.

<Acid diffusion control agent (D)>
The radiation sensitive resin composition of this invention can contain an acid diffusion control agent as (D) component as needed. Examples of the acid diffusion controller (D) include a compound represented by the following formula (11) (hereinafter referred to as “nitrogen-containing compound (I)”), a compound having two nitrogen atoms in the same molecule (hereinafter referred to as “nitrogen-containing compound (I)”). , “Nitrogen-containing compound (II)”), compounds having 3 or more nitrogen atoms (hereinafter referred to as “nitrogen-containing compound (III)”), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, etc. Can be mentioned. When an acid diffusion control agent is contained, the pattern shape and dimensional fidelity as a resist can be improved. The content of the acid diffusion control agent (D) in the radiation-sensitive resin composition is the form of the acid diffusion control agent, which is a compound as described later, and other forms such as the polymer (A) and the polymer (C). Either the acid diffusion control group incorporated as part of the polymer or both of these forms may be used.
(In formula (11), R ^N1 , R ^N2 and R ^N3 each independently represent a hydrogen atom, an optionally substituted linear, branched or cyclic alkyl group, aryl group or aralkyl group. .)

  Examples of the nitrogen-containing compound (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine; aromatic amines such as aniline. be able to.

  Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, and the like.

  Examples of the nitrogen-containing compound (III) include polymers of polyethyleneimine, polyallylamine, dimethylaminoethylacrylamide, and the like.

  Examples of amide group-containing compounds 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 urea compounds include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tributylthiourea and the like. it can.

  Examples of the nitrogen-containing heterocyclic compound include pyridines such as pyridine and 2-methylpyridine, as well as pyrazine and pyrazole.

Moreover, the compound which has an acid dissociable group can also be used as said nitrogen-containing organic compound.
Examples of the nitrogen-containing organic compound having such an acid dissociable group 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-butoxycarbonyl) diphenylamine, N- (t-butoxycarbonyl) -4-hydroxypiperidine, N- (t-amyloxycarbonyl) -4-hydroxypiperidine and the like can be mentioned.

Moreover, as an acid diffusion control agent, the compound represented by following formula (12) can also be used.
X ⁺ Z ^- ··· (12)
(In the formula (12), X ⁺ is a cation represented by the following formula (12-1-1) or (12-1-2). Z ⁻ is OH ⁻ or R ^D1 —COO ⁻ . An anion represented by R ^D1 —SO ₃ ^— , or an anion represented by R ^D1 —N ^— SO ₂ —R ^D2 (wherein R ^D1 is substituted) An alkyl group, a monovalent aliphatic cyclic hydrocarbon group, or an aryl group, wherein R ^D2 is an alkyl group in which some or all of the hydrogen atoms are substituted with fluorine atoms, or a monovalent aliphatic cyclic hydrocarbon group; ))
(In the formula (12-1-1), R ^{D3 to} R ^D5 are each independently a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom. In the formula (12-1-2), R D ^D6 and R ^D7 are each independently a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom.)

  The above compound is used as an acid diffusion control agent that is decomposed by exposure and loses acid diffusion controllability (hereinafter also referred to as “photodegradable acid diffusion control agent”). By containing this compound, the acid diffuses in the exposed area, and the acid diffusion is controlled in the unexposed area, so that the contrast between the exposed area and the unexposed area is excellent (that is, the boundary between the exposed area and the unexposed area). Therefore, it is effective in improving LWR and MEF of the radiation sensitive resin composition of the present invention.

X ⁺ in the formula (12) is a cation represented by the general formula (12-1-1) or (12-1-2) as described above. R ^{D3 to} R ^D5 in the formula (12-1-1) are each independently a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom, and among these, the development of the above compound A hydrogen atom, an alkyl group, an alkoxy group, and a halogen atom are preferred because of the effect of reducing the solubility in the liquid. R ^D6 and R ^D7 in the above formula (12-1-2) are each independently a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom, and among these, a hydrogen atom, an alkyl group, A halogen atom is preferred.

^Z in the above formula (12) - ^is, OH ^-, R D1 -COO ^- anion represented ^by, R D1 -SO ₃ ^- anion represented, the formula ^R D1 ^-N - _-SO 2 ^{-R D2} It is an anion represented by. However, R ^D1 in these formulas is an optionally substituted alkyl group, aliphatic cyclic hydrocarbon group or aryl group, and among these, the effect of lowering the solubility of the above-mentioned compound in a developer is effective. Therefore, an aliphatic cyclic hydrocarbon group or an aryl group is preferable.

  Examples of the optionally substituted alkyl group in the above formula (12) include a hydroxyalkyl group having 1 to 4 carbon atoms such as a hydroxymethyl group; an alkoxyl group having 1 to 4 carbon atoms such as a methoxy group; a cyano group; Examples thereof include a group having one or more substituents such as a cyanoalkyl group having 2 to 5 carbon atoms such as a cyanomethyl group. Among these, a hydroxymethyl group, a cyano group, and a cyanomethyl group are preferable.

  Examples of the optionally substituted aliphatic cyclic hydrocarbon group in the above formula (12) include cycloalkane skeletons such as hydroxycyclopentane, hydroxycyclohexane, and cyclohexanone; 1,7,7-trimethylbicyclo [2.2. 1] A monovalent group derived from an aliphatic cyclic hydrocarbon such as a bridged aliphatic cyclic hydrocarbon skeleton such as heptan-2-one (camphor). Among these, a group derived from 1,7,7-trimethylbicyclo [2.2.1] heptan-2-one is preferable.

  Examples of the optionally substituted aryl group in the above formula (12) include a phenyl group, a benzyl group, a phenylethyl group, a phenylpropyl group, a phenylcyclohexyl group, and the like. The thing substituted by group etc. can be mentioned. Among these, a phenyl group, a benzyl group, and a phenylcyclohexyl group are preferable.

Z ⁻ in the above formula (12) is an anion represented by the following formula (12-2-1) (that is, an anion represented by R ^D1 —COO ^{— in} which R ^D1 is a phenyl group), 12-2-2) (that is, R ^D1 is a group derived from 1,7,7-trimethylbicyclo [2.2.1] heptan-2-one and is represented by R ^D1 —SO ₃ ^— . Anion) or an anion represented by the following formula (12-2-3) (that is, R ^D1 is a butyl group, and R ^D2 is a trifluoromethyl group, R ^D1 —N ^— SO ₂ —R ^D2 It is preferable that it is an anion represented by these.

  The photodegradable acid diffusion controller is represented by the general formula (12), and specifically, is a sulfonium salt compound or an iodonium salt compound that satisfies the above conditions.

Examples of the sulfonium salt compound include triphenylsulfonium hydroxide, triphenylsulfonium salicylate, triphenylsulfonium 4-trifluoromethyl salicylate, diphenyl-4-hydroxyphenylsulfonium salicylate, triphenylsulfonium 10- Examples include camphorsulfonate, 4-t-butoxyphenyl diphenylsulfonium 10-camphorsulfonate, and the like.
In addition, these sulfonium salt compounds can be used individually by 1 type or in combination of 2 or more types.

  Examples of the iodonium salt compound include bis (4-t-butylphenyl) iodonium hydroxide, bis (4-t-butylphenyl) iodonium salicylate, bis (4-t-butylphenyl) iodonium 4- Examples thereof include trifluoromethyl salicylate and bis (4-t-butylphenyl) iodonium 10-camphorsulfonate. In addition, these iodonium salt compounds can be used individually by 1 type or in combination of 2 or more types.

In addition, an acid diffusion control agent (D) can be used individually by 1 type or in combination of 2 or more types. The content of the acid diffusion controller (D) is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less with respect to 100 parts by mass of the total amount of the polymer contained in the radiation-sensitive resin composition.
If the acid diffusion control agent (D) is contained excessively, the sensitivity of the formed resist film may be significantly reduced.

<Solvent (E)>
The radiation-sensitive resin composition of the present invention usually contains a solvent. The solvent used is not particularly limited as long as it is a solvent that can dissolve at least the polymer (A), the acid generator [B], and the polymer (C) that is optionally contained. Examples of the solvent (E) include linear or branched ketones; cyclic ketones; propylene glycol monoalkyl ether acetates; 2-hydroxypropionic acid alkyls; 3-alkoxypropionic acid alkyls. Etc. can be used.

  Among these, linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, and the like are preferable. More preferred are propylene glycol monomethyl ether acetate and cyclohexanone. These solvent can be used individually by 1 type or in mixture of 2 or more types.

<Additive (F)>
In addition to the above, the radiation-sensitive resin composition of the present invention contains, as necessary, an uneven distribution accelerator, a surfactant, an alicyclic compound, a sensitizer, a crosslinking agent, and the like as an additive (F). be able to.

(Uniformity promoting agent)
The uneven distribution accelerator has an effect of causing the polymer (A) to segregate more efficiently on the resist film surface. By adding this uneven distribution promoter to the radiation sensitive resin composition, the amount of the polymer (A) added can be reduced as compared with the conventional case. Therefore, elution of components from the resist film to the immersion liquid can be further suppressed without impairing basic resist characteristics such as LWR, development defects, and pattern collapse resistance, and immersion exposure can be performed at high speed by high-speed scanning. It becomes possible. Moreover, immersion-derived defects such as watermark defects can be suppressed. Examples of such an uneven distribution promoter include low molecular compounds having a relative dielectric constant of 30 or more and 200 or less and a boiling point at 1 atm of 100 ° C. or more. Specific examples of such compounds include lactone compounds, carbonate compounds, nitrile compounds, and polyhydric alcohols.

  Specific examples of the lactone compound include γ-butyrolactone, valerolactone, mevalonic lactone, norbornane lactone, and the like.

  Specific examples of the carbonate compound include propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, and the like.

  Specific examples of the nitrile compound include succinonitrile. Specific examples of the polyhydric alcohol include glycerin and the like.

  In the radiation-sensitive resin composition of the present invention, the content of the uneven distribution accelerator is preferably 10 to 500 parts by mass when the total amount of the polymer is 100 parts by mass. As said uneven distribution promoter, only 1 type may be contained and 2 or more types may be contained.

(Surfactant)
A surfactant is a component that exhibits an effect of improving coatability, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol In addition to nonionic surfactants such as distearate, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (manufactured by Tochem Products), MegaFuck 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 (made by Asahi Glass Co., Ltd.), etc. Can do. These surfactants can be used individually by 1 type or in mixture of 2 or more types. The content of the surfactant is usually 2 parts by mass or less with respect to 100 parts by mass of the total amount of the polymer contained in the radiation-sensitive resin composition.

(Alicyclic skeleton compound)
The alicyclic skeleton-containing compound is a component having an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like. Examples of the alicyclic skeleton-containing compound include:
Adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, 1-adamantanecarboxylate t-butyl;
Deoxycholic acid esters such as t-butyl deoxycholate, t-butoxycarbonylmethyl deoxycholic acid, 2-ethoxyethyl deoxycholic acid;
Lithocholic acid esters such as t-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid;
3- [2-Hydroxy-2,2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] nonane, and the like. These alicyclic skeleton-containing compounds can be used singly or in combination of two or more. The compounding quantity of an alicyclic frame | skeleton compound is 50 mass parts or less normally with respect to 100 mass parts of total amounts of the polymer contained in the said radiation sensitive resin composition, Preferably it is 30 mass parts or less.

(Sensitizer)
The sensitizer absorbs energy other than the energy of radiation absorbed by the acid generator (C), and transmits the energy to the acid generator (C) in the form of, for example, radicals. It has the effect of increasing the production amount, and has the effect of improving the “apparent sensitivity” of the radiation-sensitive resin composition.

  Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like. These sensitizers can be used individually by 1 type or in mixture of 2 or more types.

(Crosslinking agent)
When the radiation-sensitive resin composition of the present invention is used as a negative-type radiation-sensitive resin composition, a compound capable of crosslinking a polymer soluble in an alkali developer in the presence of an acid (hereinafter referred to as “crosslinking agent”). May be blended). Examples of the crosslinking agent include compounds having at least one functional group having a crosslinking reactivity with a polymer soluble in an alkali developer (hereinafter referred to as “crosslinkable functional group”).

  Examples of the crosslinkable functional group include glycidyl ether group, glycidyl ester group, glycidyl amino group, methoxymethyl group, ethoxymethyl group, benzyloxymethyl group, acetoxymethyl group, benzoyloxymethyl group, formyl group, acetyl group, Examples thereof include a vinyl group, an isopropenyl group, a (dimethylamino) methyl group, a (diethylamino) methyl group, a (dimethylolamino) methyl group, a (diethylolamino) methyl group, and a morpholinomethyl group.

  Examples of the crosslinking agent include those described in paragraphs [0169] to [0172] of International Publication No. 2009/51088.

  As the crosslinking agent, a methoxymethyl group-containing compound, more specifically, dimethoxymethylurea, tetramethoxymethylglycoluril and the like are particularly preferable. In the negative radiation sensitive resin composition, the crosslinking agent can be used alone or in admixture of two or more.

  The amount of the crosslinking agent used is preferably 5 to 95 parts by mass, more preferably 15 to 85 parts by mass, and particularly preferably 20 to 75 parts by mass with respect to 100 parts by mass of the polymer soluble in the alkali developer. . In this case, if the amount of the crosslinking agent used is less than 5 parts by mass, the remaining film ratio tends to decrease, the pattern meanders or swells easily, and if it exceeds 95 parts by mass, the alkali developability decreases. Tend.

  As the additive (F), in addition to the above, dyes, pigments, adhesion aids and the like can be used. For example, by using a dye or a pigment, the latent image of the exposed area can be visualized, and the influence of halation during exposure can be reduced. Moreover, the adhesiveness with a board | substrate can be improved by mix | blending an adhesion aid. Examples of other additives include alkali-soluble resins, low-molecular alkali-solubility control agents having an acid-dissociable protecting group, antihalation agents, storage stabilizers, and antifoaming agents.

  As the additive (F), one of the various additives described above may be used alone, or two or more of them may be used in combination.

<Preparation of radiation sensitive resin composition solution>
The radiation-sensitive resin composition of the present invention is usually dissolved in a solvent so that the total solid content concentration is 1 to 50% by mass, preferably 1 to 25% by mass, and then, for example, the pore size is 0.02 μm. It is prepared as a composition solution by filtering through a filter of the degree.

  In addition, the said radiation sensitive resin composition is so preferable that there is little content of impurities, such as a halogen ion and a metal. When the content of such impurities is small, the sensitivity, resolution, process stability, pattern shape and the like of the resist film can be further improved. Therefore, the polymer (A) and the polymer (B) to be contained in the radiation sensitive resin composition are, for example, chemical purification methods such as washing with water, liquid-liquid extraction, liquid removal through a demetal filter, etc. It is preferable to purify by a combination of a physical purification method and a physical purification method such as ultrafiltration and centrifugation.

<Method for forming photoresist pattern>
The resist pattern forming method of the present invention includes (1) a step of forming a photoresist film on a substrate using a radiation sensitive resin composition (hereinafter also referred to as “step (1)”), and (2). A step of placing an immersion exposure liquid on the photoresist film and subjecting the photoresist film to immersion exposure via the immersion exposure liquid (hereinafter also referred to as “step (2)”); 3) A step of developing the photoresist film subjected to immersion exposure to form a resist pattern (hereinafter also referred to as “step (3)”). According to such a forming method, a resist pattern having a good pattern shape can be formed.

  In the step (1), the solution of the radiation-sensitive resin composition of the present invention is applied, for example, to a silicon wafer, a wafer coated with aluminum, or the like by an appropriate application means such as spin coating, cast coating, roll coating or the like. By applying on the substrate, a photoresist film is formed. Specifically, after applying the radiation-sensitive resin composition solution so that the resulting resist film has a predetermined thickness, the solvent in the film is volatilized by pre-baking (PB) to form a resist film. Is done.

  Although the thickness of the said resist film is not specifically limited, It is preferable that it is 10-5000 nm, and it is more preferable that it is 10-2000 nm.

  Moreover, although the prebaking heating conditions change with composition of a radiation sensitive resin composition, it is preferable that it is about 30-200 degreeC, More preferably, it is 50-150 degreeC.

  In the above step (2), an immersion exposure liquid is disposed on the photoresist film formed in the step (1), and radiation is irradiated through the immersion exposure liquid to expose the photoresist film to the immersion exposure. To do.

  As the liquid for immersion exposure, for example, pure water, a long chain or cyclic aliphatic compound, or the like can be used.

  The radiation is appropriately selected from visible rays, ultraviolet rays, far ultraviolet rays, X-rays, charged particle beams, etc., depending on the type of the acid generator (C) used. ArF excimer laser (wavelength 193 nm) or far ultraviolet rays represented by KrF excimer laser (wavelength 248 nm) are preferable, and ArF excimer laser (wavelength 193 nm) is particularly preferable.

  Moreover, exposure conditions, such as exposure amount, can be suitably selected according to the composition of the radiation-sensitive resin composition, the type of additive, and the like.

  In the present invention, heat treatment (PEB) is usually performed after exposure. By this PEB, the deprotection reaction of the acid dissociable group in the resin component can be smoothly advanced. Although the heating conditions of PEB are suitably adjusted with the compounding composition of a radiation sensitive resin composition, they are 30-200 degreeC normally, Preferably it is 50-150 degreeC.

  In the present invention, in order to maximize the potential of the radiation-sensitive resin composition, it is used as disclosed in, for example, Japanese Patent Publication No. 6-12452 (Japanese Patent Laid-Open No. 59-93448). An organic or inorganic antireflection film can also be formed on the substrate to be formed. In order to prevent the influence of basic impurities contained in the environmental atmosphere, a protective film can be provided on the photoresist film as disclosed in, for example, Japanese Patent Laid-Open No. 5-188598. These techniques can be used in combination.

  In the step (3), a desired resist pattern is formed by developing the exposed resist film.

  Examples of the developer used in this development step include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-. Propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5- An alkaline aqueous solution in which at least one alkaline compound such as diazabicyclo- [4.3.0] -5-nonene is dissolved is preferable.

  The concentration of the alkaline aqueous solution is preferably 10% by mass or less. When the concentration of the alkaline aqueous solution exceeds 10% by mass, the unexposed area may be dissolved in the developer.

  An organic solvent can also be added to the developer composed of the alkaline aqueous solution. 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 alcohol. Alcohols such as i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol and 1,4-hexanedimethylol; ethers such as tetrahydrofuran and dioxane; Examples thereof include esters such as ethyl acetate, n-butyl acetate and i-amyl acetate; aromatic hydrocarbons such as toluene and xylene; phenol, acetonylacetone and dimethylformamide. These organic solvents may be used individually by 1 type, and may be used in combination of 2 or more type.

  The amount of the organic solvent used is preferably 100 parts by volume or less with respect to 100 parts by volume of the alkaline aqueous solution. When the usage-amount of an organic solvent exceeds 100 volume part, developability may fall and there exists a possibility that the image development residue of an exposure part may increase. An appropriate amount of a surfactant or the like can be added to the developer composed of the alkaline aqueous solution. In addition, after developing with the developing solution which consists of alkaline aqueous solution, generally it wash | cleans with water and dries.

<Resist film>
The resist film in the present invention is formed, for example, by the above-described method using the radiation-sensitive resin composition of the present invention. The radiation-sensitive resin composition includes the polymer (A) having the repeating unit (a1) as described above, and is contained in the polymer (A) or in a different weight from the polymer (A). The combined unit (B) contains the repeating unit (f1). When a fluorine-containing repeating unit is introduced into the polymer, the MEEF value may increase, but at least a part of the polymer component may be reduced by a combination of the repeating unit (a1) and the repeating unit (f1). By comprising, a resist film having a high surface hydrophobicity and a small MEEF can be obtained. In particular, the resist film of the present invention is excellent in that the hole pattern can have a good pattern shape.

  Hereinafter, the present invention will be described with specific examples, but the present invention is not limited to the specific examples illustrated below. In the examples, synthesis examples and comparative examples, “parts” and “%” are on a molar basis unless otherwise specified.

1. Measurement method and evaluation method of various physical properties [polystyrene equivalent weight average molecular weight (Mw)]
A gel based on monodisperse polystyrene using Tosoh's GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) under analysis conditions of flow rate 1.0 ml / min, elution solvent tetrahydrofuran, column temperature 40 ° C It was measured by permeation chromatography (GPC).

[Number average molecular weight in terms of polystyrene (Mn)]
A gel based on monodisperse polystyrene using Tosoh's GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) under analysis conditions of flow rate 1.0 ml / min, elution solvent tetrahydrofuran, column temperature 40 ° C It was measured by permeation chromatography (GPC).

[ ¹ H-NMR analysis, ¹³ C-NMR analysis]
NMR analysis was performed using a nuclear magnetic resonance apparatus (trade name: JNM-ECX400, manufactured by JEOL Ltd.).

[Evaluation of hole forming ability]
First, a lower layer (trade name “ARC66”, manufactured by Nissan Chemical Co., Ltd.) is spin-coated on a 12-inch silicon wafer using a trade name “Lithius Pro-i”, and then at 205 ° C. for 60 seconds. A film having a film thickness of 105 nm was formed by baking. Next, a radiation sensitive resin composition was spin-coated using the trade name “CLEAN TRACK ACT12”, PB was performed at 100 ° C. for 60 seconds, and then cooled at 23 ° C. for 30 seconds to coat with a film thickness of 120 nm. A film was formed.

  Next, an ArF immersion exposure apparatus (trade name “NSR-S610C”, manufactured by Nikon) was used for the formed coating film, NA: 1.20 (Outerσ / innerσ = 0.92 / 0.72), Under the optical conditions of DiPOLE (open angle 35 degrees), exposure was performed through a pattern forming mask having 70 nm holes / 140 nm pitch in the X direction and 210 nm holes / 225 nm pitch in the Y direction. Then, after a 60 second post-exposure bake (PEB) at a temperature (PEB temperature) shown in Table 4 below on a hot plate with a trade name “CLEAN TRACK LITHIUS PROI (manufactured by Tokyo Electron Ltd.)”, 30 ° C. at 30 ° C. After cooling for 2 seconds, a 2.38% tetramethylammonium hydroxide aqueous solution was used as a developing solution for paddle development (10 seconds) with a GP nozzle of the developing cup, and rinsed with ultrapure water. Thereafter, the substrate for evaluation on which a resist pattern was formed was obtained by spin-drying by shaking off at 2000 rpm for 15 seconds.

When the substrate for evaluation was obtained, the exposure amount (mJ / cm ² ) on which a resist pattern having a hole X-axis length of 70 nm was defined as the optimum exposure amount. The top part of the hole pattern at the optimum exposure amount was observed with a scanning electron microscope (“CG-4000”, manufactured by Hitachi High-Technologies Corporation). A resist pattern with this optimum exposure amount in which no white edge occurred was regarded as good shape, and a resist pattern in which white edge occurred was regarded as defective. Specific examples of the case where the shape is good and the case where the shape is bad are shown in FIG. In FIG. 1, (a) is a case where the shape is good, and (b) to (d) are cases where the shape is poor. In the drawings (b) to (d), the pattern top portion appears white with a certain width. The larger this width is, the worse the shape is (the white edge is generated).

[Evaluation of MEEF]
(1) Preparation of evaluation substrate and determination of optimum exposure amount:
First, a coating film was formed on a 12-inch silicon wafer using the same method as the coating film formed in the evaluation of the hole forming ability. Next, using an ArF immersion exposure apparatus (trade name “S610C”, manufactured by NIKON), NA: 1.30 (Outerσ / innerσ = 0.777 / 0.782), the target size under the optical conditions of Crospore Were exposed through a mask on which patterns of 40 nm line / 84 nm pitch, 42 nm line / 84 nm pitch, and 44 nm line / 84 nm pitch were formed. After a 60-second post-exposure bake (PEB) on the hot plate of the trade name “Lithius Pro-i” at the temperature (PEB temperature) shown in Table 4 below, 2.38% using a GP nozzle of the developing cup. Paddle development (10 seconds) was performed using a tetramethylammonium hydroxide aqueous solution as a developer, and rinsed with ultrapure water. A substrate on which a resist pattern was formed was obtained by spin-drying by shaking off at 2000 rpm for 15 seconds. At this time, an exposure amount at which a resist pattern having a 42 nm line / 84 nm pitch was formed on a portion exposed through a mask having a target size of 42 nm line / 84 nm pitch was determined as the optimum exposure amount.

(2) MEEF measurement:
The difference in the line width of the resist pattern obtained for a portion exposed through a mask having a target size of 40 nm line / 84 nm pitch and 44 nm line / 84 nm pitch at the above optimal exposure amount is obtained as a pattern size difference (44 nm) of the mask target size. The value divided by −40 nm = 4 nm) was calculated as MEEF. The value of MEEF can be expressed as follows.
MEEF = difference in line width of formed resist pattern (A−B) / difference in pattern size of mask A: line width of resist pattern formed with mask having target size of 44 nm line / 84 nm pitch (nm)
B: Line width (nm) of a resist pattern formed with a mask having a target size of 40 nm line / 84 nm pitch

3. Synthesis of Polymer (A) Polymers (A-1) to (A-24) were synthesized using the monomers shown in Table 1 below.

In Table 1, “content ratio” indicates the molar ratio of repeating units derived from each monomer when all repeating units in the polymer are set to 1 (the same applies to Table 2 below). Abbreviations of monomers indicate the following compounds, respectively.

4). Synthesis of Polymer (B) Polymers (B-1) to (B-7) were synthesized using the monomers shown in Table 2 below.

In the table, the abbreviations of monomers indicate the following compounds, respectively.

5. Preparation of Radiation Sensitive Resin Composition The radiation sensitive resin compositions of Examples 1 to 31 (hereinafter also referred to as “compositions”) were prepared according to the compositions shown in Table 3 below, and comparative examples according to the compositions shown in Table 4 below. Compositions 1-9 were prepared.

In the table, the abbreviations of the constituent components (acid generator (C), acid diffusion controller (D), solvent (E)) other than the polymer (A) and the polymer (B) are the following compounds, respectively. Show.
<Acid generator (C)>

<Acid diffusion control agent (D)>
(D-1): Tris (2-methoxymethoxyethyl) amine

<Solvent (E)>
(E-1): Propylene glycol monomethyl ether acetate (E-2): Cyclohexanone

5. Evaluation of Lithographic Performance For the compositions of Examples 1 to 35 and Comparative Examples 1 to 9 obtained, the hole forming ability and the MEEF of the line pattern were evaluated. The evaluation results are shown in Table 5 below for the examples and in Table 6 below for the comparative examples.

  First, for the compositions of Examples 1 to 35, there was almost no gap between holes in the hole pattern, and as shown in Table 5, there was almost no white edge. From these results, it was found that a line pattern having a good shape could be obtained with the compositions of Examples 1 to 35. The line pattern also showed a low value of MEEF of 4.1 or less. From the above, it was found that in the compositions of Examples 1 to 35, not only the hole pattern but also the pattern shape of the line pattern was good.

  On the other hand, when it sees about a comparative example, in Comparative Examples 1-3 using the same thing as Examples 1-4 as a polymer (A), although MEEF of a line pattern showed the value equivalent to Examples 1-35. White edges were observed in the hole pattern. In Comparative Examples 4 to 9, both the MEEF and the hole forming ability of the line pattern were not good.

Claims (6)

Containing a polymer component,
In the polymer component, the repeating unit (a1) represented by the following formula (1), the following formula (F1-1), the following formula (F1-2) and the following formula (F1-3) are represented. A radiation-sensitive resin composition having at least one repeating unit (f1) selected from the group consisting of repeating units.
(In the formula, R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group or an alkyl group having 1 to 3 carbon atoms, and R ²⁰ is an (n + 2) -valent hydrocarbon group having 1 to 5 carbon atoms. , X is a single bond, —OCO—, —CO—NH—, —NH— or —CO—, n is an integer of 0 to 3, and m is an integer of 0 to 10. N + m ≧ 1.)
(In the formula, R ¹ represents a hydrogen atom, a fluorine atom, a trifluoromethyl group or an alkyl group having 1 to 3 carbon atoms, and X ^f1 represents the following formula (X-1), (X-2) or (X -3).)
(In the formula, R ^2a , R ^2b , R ^3a , R ^3b , R ^5a , R ^5b , R ^6a , R ^6b , R ^7a , R ^7b , R ^8a , R ^8b , R ^9a and R ^9b are each independently , A hydrogen atom, a hydroxyl group, a halogen atom, or a monovalent organic group having 1 to 15 carbon atoms, provided that four R's represented by R ^2a , R ^2b , R ^3a, and R ^3b in formula (X-1) A group consisting of six Rs of R ^5a , R ^5b , R ^6a , R ^6b , R ^7a and R ^7b in formula (X-2); R ^8a , R ^8b in formula (X-3) Any one of R in each group of R ^9a and R ^9b is bonded to an oxygen atom by elimination of one hydrogen atom of R in the above definition. Carbon atoms in which two R are bonded to each other in the group Good .R ⁴ also together form a ring structure, an alkyl group or a monovalent alicyclic hydrocarbon group having 1 to 20 carbon atoms, part of the hydrogen atoms may be substituted with a halogen atom, A part of the methylene group may be substituted with an oxygen atom or a carbonyl group.)
(In the formula, R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group or an alkyl group having 1 to 3 carbon atoms, R ^S is a divalent linking group, and R ¹² has 2 to 2 carbon atoms. 20 chained or cyclic fluorinated alkyl groups.)
(In the formula, R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms. R ^13a and R ^13b are each independently a hydrogen atom or a carbon number of 1 to 15 carbon atoms. an alkyl group or a monovalent alicyclic hydrocarbon group. However, good .R ¹⁴ also form a ring together with the carbon atom to which the R ^13a and R ^13b is which they are attached are fluorine (It is a C1-C15 alkyl group which may have an atom, or a monovalent alicyclic hydrocarbon group, or an acid dissociable group.) The radiation sensitive resin composition of Claim 1 which has at least the repeating unit represented by a following formula (F1-2-1) as the said repeating unit (f1) in the said polymer component.
Wherein R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group or an alkyl group having 1 to 3 carbon atoms, R ¹⁰ is a methylene group or an oxygen atom, and R ¹¹ is a hydrogen atom, methyl A group or a trifluoromethyl group, and R ¹² is a chain or cyclic fluorinated alkyl group having 2 to 20 carbon atoms.) The radiation sensitive resin composition of Claim 1 or 2 which has a repeating unit (p1) represented by following formula (2) in the said polymer component.
(In the formula, R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms. R ¹⁵ , R ^16, and R ¹⁷ are each independently one having 1 to 4 carbon atoms. An alkyl group or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, provided that R ¹⁶ and R ¹⁷ are a ring having 4 to 20 carbon atoms together with the carbon atoms to which they are bonded to each other; A structure may be formed.) The radiation sensitive resin composition as described in any one of Claims 1 thru | or 3 which has a repeating unit (L1) represented by following formula (3) in the said polymer component.
(In the formula, R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms, R ^L1 is a single bond or a divalent linking group, and R ^Lc is a lactone. (It is a monovalent organic group having a structure.) As the polymer component,
A polymer (A) having the repeating unit (a1);
The radiation sensitive resin composition as described in any one of Claims 1 thru | or 4 containing the polymer (B) which has the said repeating unit (f1). Using the radiation-sensitive resin composition according to claim 1 to form a resist film on a substrate;
Disposing an immersion exposure liquid on the resist film, and exposing the resist film through the immersion exposure liquid;
After the exposure, a step of developing the resist film to form a resist pattern;
A resist pattern forming method comprising: