JP2006085081A - Method for forming fine pattern and resist composition used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist composition giving excellent solubility to a resist coating on exposure to light particularly at 193 nm wavelength, and to provide a method for forming a fine pattern with excellent contrast by using the resist composition. <P>SOLUTION: The resist composition comprises (a) an acid dissociable functional group-containing polymer, (b) a photo-acid generating agent and (c) a dissolution inhibitor. The dissolution inhibitor (c) consists of a polymer necessarily containing a structural unit derived from at least one kind of monomer (m1) selected from fluorine-containing norbornene derivatives having a moiety expressed by formula (1). In the formula (1), Rf<SP>1</SP>and Rf<SP>2</SP>may be same or different and each represents a 1-10C fluorine-containing alkyl group which may have an ether bond; X represents F or CF<SP>3</SP>; and Y<SP>1</SP>represents an OH group or an acid dissociable functional group which is dissociated by an acid to change into an OH group. In the method for forming a fine pattern, a fine pattern is formed by using the resist composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fine pattern forming method capable of improving the solubility of a resist film at the time of forming a fine pattern by blending a specific polymer as a dissolution inhibitor in the resist composition, and a resist composition used therefor.

  Various electronic components such as semiconductor integrated circuits require ultra-fine processing, and resists are widely used in the processing technology. In addition, with the increase in functionality and density of electronic components, there is a demand for ultra-fine resist patterns to be formed.

  Up to now, as the resin component of the chemically amplified resist, polyhydroxystyrene having high transparency with respect to KrF excimer laser (248 nm) and those obtained by protecting this hydroxy group with an acid-dissociable protecting group have been mainly used. I came. However, due to recent demands for miniaturization of semiconductor elements, the light source has shifted from a KrF excimer laser to a process using an ArF excimer laser (193 nm) having a shorter wavelength.

  By the way, in a process using an ArF excimer laser (193 nm) as a light source, a resin having an aromatic ring such as polyhydroxystyrene which has been conventionally used cannot be used because of insufficient transparency with respect to the ArF excimer laser. As a base polymer of a resist material in a lithography process, a method of introducing an aliphatic ring structure instead of an aromatic ring is known. For example, Patent Document 1 proposes a chemically amplified resist using a polymer in which an aliphatic ring structure is introduced into an ester site of a (meth) acrylic resin. Patent Document 2 proposes a chemically amplified resist using a resin having a norbornene skeleton in the main chain.

A process using an F ₂ laser (157 nm) as a light source is being studied with the aim of further miniaturization, and a fluorine-containing polymer having excellent transparency of ultraviolet rays having a shorter wavelength may be used as a base polymer for resist. It is being considered.

In the examination of these resist compositions, for the purpose of improving the contrast during development, in addition to the base polymer and the photoacid generator, a high-molecular or low-molecular additive (dissolution inhibitor) was added to the resist composition. Various multi-component compositions having more than the components have been proposed (for example, Patent Document 3, Patent Document 4, Patent Document 5, etc.). Mixing these conventional additives (dissolution inhibitors) has the problem of reducing transparency and dry etching resistance when used in ArF resists and F ₂ resists, even if it has an effect of improving resolution. there were.

In addition, as a result of reducing the compatibility with the base polymer in the resist composition, the pattern shape becomes insufficient even when the resolution is improved, for example, there is a problem that the line edge roughness (LER) is deteriorated. From the viewpoint of transparency to F ₂ laser and ArF excimer laser, polymers introduced with hexafluoroisopropanoyl groups as alkali-soluble groups instead of phenolic hydroxy groups and carboxylic acids so far have been studied as base polymers for resists. Has good transparency and dry etching resistance.

  For example, in Patent Document 6, a resin having a norbornene skeleton using a hexafluoroisopropanoyl group as an alkali-soluble group in the main chain is proposed as a resist base polymer. Since the acidity is low, the solubility of the unprotected resin in the developer becomes insufficient, and it is difficult to use the exemplified resin as a dissolution inhibitor here. Moreover, there is no example of what introduce | transduced F atom into the norbornene skeleton.

  In Patent Document 7, an alternating copolymer of tetrafluoroethylene and an OH group-containing norbornene derivative is proposed as a resist base polymer. In order to improve the solubility of the norbornene derivative in these polymers in an alkaline developer, there has been an attempt to increase the acidity of the OH group by introducing F atoms into adjacent carbon atoms of the hexafluoroisopropanoyl group. Has been made. However, since the content of hexafluoroisopropanoyl groups in this resin (the content of hexafluoroisopropanoyl group-containing norbornene units) is low, the developer solubility of the unprotected resin becomes insufficient, and as a dissolution inhibitor It is difficult to use.

  From the above viewpoints, the conventional technology is transparent to short-wave ultraviolet rays, particularly ultraviolet rays having a wavelength of 193 nm or less, has excellent dry etching resistance, and can improve development contrast after exposure and improve pattern shape. There is no effective dissolution inhibitor that can be obtained.

JP-A-7-234511 Japanese Patent Laid-Open No. 10-218941 JP 2000-98614 A JP 2001-281847 A JP 2004-182796 A JP 2002-72484 A WO 01/74916 pamphlet

  The present invention provides a resist composition that gives a resist film excellent solubility and contrast especially when exposed to ultraviolet light having a wavelength of 193 nm or less, and a method for forming a fine pattern using the resist composition. Objective.

The present invention
(I) (a) an acid-dissociable functional group-containing polymer,
A step of producing a resist composition comprising (b) a photoacid generator and (c) a dissolution inhibitor;
(II) a step of forming a resist film made of the resist composition on the substrate or a predetermined layer on the substrate;
(III) a step of selectively irradiating a predetermined region of the resist film with an energy ray for exposure; and (IV) developing the resist film after the exposure to selectively expose an exposed portion of the resist film. A fine pattern forming method comprising a step of removing and forming a fine pattern, wherein the dissolution inhibitor (c) is represented by the formula (M-1):
-(M1)-(M2)-(N1)-(M-1)
[Where:
M1 is a structural unit derived from a norbornene derivative, and in M1, formula (1):

(Wherein Rf ¹ and Rf ² are the same or different and may contain an ether bond, a C 1-10 fluorine-containing alkyl group; X is F or CF ₃ ; Y ¹ is an OH group and / or an acid; A structural unit derived from at least one monomer (m1) selected from fluorine-containing norbornene derivatives having a site represented by an acid-dissociable functional group that dissociates and changes to an OH group;
M2 is a structural unit derived from at least one monomer (m2) selected from a fluorine-containing norbornene derivative having an acid-dissociable functional group Y ² that is dissociated by a —COOH group and / or an acid to change to a —COOH group;
N1 is a structural unit derived from the monomer (n1) copolymerizable with the monomer (m1) and / or the monomer (m2).
The structural unit M1 is 55 to 100 mol%, the structural unit M2 is 0 to 45 mol%, the structural unit N1 is 0 to 20 mol%, and M1 + M2 is 80 to 100 mol% And a polymer (A) having a molar ratio of M1 / M2 of 55/45 to 100/0 is used.

  The present invention also relates to a resist composition comprising an acid-dissociable functional group-containing polymer (a), a photoacid generator (b) and a dissolution inhibitor (c) used for forming such a fine pattern.

  The present invention provides a resist composition that gives a resist film excellent solubility particularly when exposed to light having a wavelength of 193 nm or less, and a method for forming a fine pattern with excellent contrast using the resist composition. Can do.

  First, the resist composition for forming a fine pattern of the present invention will be described.

The resist composition of the present invention comprises:
(A) an acid-dissociable functional group-containing polymer,
A composition comprising (b) a photoacid generator and (c) a specific dissolution inhibitor.

The greatest feature of the present invention is the formula (M-1):
-(M1)-(M2)-(N1)-(M-1)
And a polymer (A) containing a structural unit M1 derived from a fluorine-containing norbornene derivative containing an acid-dissociable functional group that is dissociated by an OH group or an acid and changes to an OH group.

  The present inventors have found that this polymer (A) is excellent in terms of transparency at a wavelength of 193 nm or less and solubility in an alkaline developer. Further, it has been found that by adding this polymer (A) to an acid-dissociable functional group-containing polymer, the developer solubility of the composition can be greatly improved.

  Since the structural unit M1 can introduce a fluorine-containing alcohol group having high acidity into the polymer (A), the structural unit M1 is excellent in that the solubility of the polymer (A) in an alkaline developer can be very high. At the same time, the developer solubility of the resist composition using the polymer (A) can be greatly improved. Furthermore, since the fluorine-containing alcohol group of the structural unit M1 is a functional group having excellent transparency at a wavelength of 193 nm or less, particularly at a wavelength of 157 nm or less, the polymer (A) having the structural unit M1 as a main component is The transparency of the resist composition against ultraviolet rays is not hindered at all. Polynorbornene containing the structural unit M1 is not described in known patents and documents.

  The structural unit M1 is a norbornene derivative-derived structural unit, and in M1, the formula (1):

(In the formula, Rf ¹ and Rf ² are the same or different, and may contain an ether bond, a C 1-10 fluorine-containing alkyl group; X is F or CF ₃ ; Y ¹ is dissociated by an OH group or an acid. And a structural unit derived from at least one monomer (m1) selected from fluorine-containing norbornene derivatives having a site represented by an acid-dissociable functional group that changes to an OH group. That is, for example, a hydrogen atom bonded to a carbon atom forming the norbornene skeleton may be substituted with a substituent containing a moiety represented by the formula (1), or a moiety of the formula (1) As such, it may be contained in the norbornene derivative skeleton.

Y ¹ is an acid dissociable functional group that dissociates with an OH group or an acid and changes to an OH group. Examples of the acid dissociable functional group that dissociates with an acid and changes to an OH group include a functional group represented by the formula: -OP (wherein P is a protecting group).

Specific examples of —O—P include, for example, formula (5-1):
-OCH ₂ OR (5-1)
(Wherein R is an organic group having 1 to 20 carbon atoms); or formula (5-2):

An acetal compound represented by the formula (wherein R is the same as in the above formula (5-1)) is particularly preferred because of its high reactivity.

  Furthermore, the formula (5-3):

(Wherein, R is the same as in the above formula (5-1));
Formula (5-4):
-OR (5-4)
(Wherein, R is the same as in the above formula (5-1)).
R in the formulas (5-1) and (5-2) is
-Z ¹ R ^1a (R-1)
-C (R ^2a ) ₃ (R-2)
-R ^3a (R-3)
[In Formula (R-1), Z ¹ represents a single bond, a linear or branched divalent organic group, or a divalent organic group having an alicyclic structure, and R ^1a represents a hydrogen atom or 1 The functional group of a valence is shown.
Wherein the (R-2), each R ^2a represents a monovalent alicyclic hydrocarbon independently represents a linear or branched alkyl group or a derivative thereof, or 4 to 20 carbon atoms having 1 to 4 carbon atoms to each other A divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, together with any two R ^2a bonded to each other, and the carbon atom to which each R ^2a is bonded. The remaining R ^2a represents a linear or branched alkyl group having 1 to 4 carbon atoms or a derivative thereof, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof.
In the formula (R-3), R ^3a has a linear or branched alkyl group having 1 to 12 carbon atoms, a monovalent organic group having 4 to 20 carbon atoms having an alicyclic structure, and a cyclic ether structure. A monovalent organic group or a monovalent organic group having an optionally substituted lactone skeleton is shown. ]
And a monovalent or divalent organic group having 1 to 20 carbon atoms represented by (a) the same as the acid dissociable protecting group in the acid dissociable functional group-containing polymer.

  R in the formulas (5-3) and (5-4) is that the monovalent or divalent organic group having 1 to 20 carbon atoms represented by (R-2) can function as a chemically amplified resist. Preferable examples include the same acid dissociable protecting groups in the acid dissociable functional group-containing polymer (a).

In particular, in the formulas (5-1) and (5-2), the organic group consisting of the formula (R-1) is preferable in terms of high reactivity, and in particular, Z ¹ has a structure represented by CH ₂ R. Organic groups are preferred because of their higher reactivity. Also in formula (5-3), the organic group consisting of formula (R-2) is particularly preferably a t-butyl group or a methyladamantyl group in terms of high reactivity.

  The Rf group in the site of the formula (1) is preferably a fluoroalkyl group, and in particular, the Rf group is one in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with fluorine atoms. If so, it is preferable in that the acidity of the OH group in the formula (1) can be increased by the effect of the substituted fluorine atom, and developer solubility can be imparted when used for resist applications.

  Accordingly, the Rf group is preferably a perfluoroalkyl group, in that the acidity of the OH group can be further increased. Specifically,

(Wherein, m is 0 or an integer of 1 to 4; m1 is 0, 1 or 2; m2 is 0 or 1), specifically, —CF ₃ , —C ₂ F ₅ , —CF ₂ CF (CF ₃ ) ₂ —CH (CF ₃ ) _{2 and the} like are preferable, and —CF ₃ , —C ₂ F ₅ , and —CF ₃ are particularly preferable.

  As the OH group-containing fluorine-containing norbornene derivative (m1-1) that gives a preferred structural unit M1, the formula (m1-1):

(Wherein X, Rf ¹ and Rf ² are the same as those in formula (1); X ¹ and X ² are the same or different; H, F or CF ₃ ; R ³ contains an ether bond having 1 to 5 carbon atoms) But and well, some or all of those selected from a divalent hydrocarbon group formed by substituted by fluorine atoms of the hydrogen atom, alkyl group R ² is H or C1-10; n2 is 0 or 1; n3 is a norbornene derivative including the moiety of the formula (1) represented by the formula (1).

  Specifically, the formula (m1-2):

An OH group-containing norbornene derivative represented by the formula (wherein X, X ¹ , X ² , n 3, R ² , Rf ¹ and Rf ² are the same as those in the formula (m1-1)) is preferable. That is, the OH group-containing fluoropolymer (A) using these is particularly preferable in that the developer dissolution rate, that is, the resolution can be effectively improved. In the formula (m1-2), it is preferable that at least one of X, X ¹ and X ² is F or CF ₃ in terms of transparency and solubility in the developer when a polymer is used.

  Among formulas (m1-2), formula (2):

Formula (m1-2a) that gives structural unit M1-2 represented by the formula (wherein X, X ¹ , X ² and Y ¹ are the same as those in formula (m1-1)):

An OH group-containing fluorine-containing norbornene derivative represented by the formula (wherein X, X ¹ and X ² are the same as those in the formula (m1-1)) is preferable.

  As the formula (m1-1), the formula (m1-3):

(Wherein Z is an oxygen atom or —CH ₂ O—; n4 is 0 or 1; Rf ¹ , Rf ² , R ² , and n3 are the same as in formula (m1-1)); Rf ³ has 1 to ³ carbon atoms perfluoroalkyl ^{group, a 1, B 1, C} 1 is also cited OH group-containing norbornene derivative represented by H or F).

In formula (m1-1) and ^{(m1-2), Rf 1, Rf} 2 has likewise be preferably mentioned those exemplified in the above-mentioned formula (1).

In formulas (m1-1) and (m1-2), R ² is selected from H or an alkyl group having 1 to 10 carbon atoms, and may be the same or different. R ² is preferably H or a CH ₃ group, and H is particularly preferable.

  Specific examples of the OH group-containing norbornene derivative of the formula (m1-2) include, for example,

(Wherein R ² is the same as in formula (m1-2), n3 is an integer of 0 to 5)
And more specifically,

Etc. are preferred.

Although the fluorine-containing norbornene derivative in which Y ¹ is an OH group in the structural unit M1 has been described above, examples of the fluorine-containing norbornene derivative in which Y ¹ is an acid-dissociable functional group represented by —O—P include the above derivatives. In the formula, a group in which the OH group is replaced with a —OP group is given together with preferred examples.

  The fluorine-containing norbornene derivative polymer (A) used for the dissolution inhibitor (c) may be a homopolymer having only the structural unit M1. Further, the structural unit M2 or N1 may be included as an arbitrary structural unit.

The structural unit M2 is a structural unit derived from at least one monomer (m2) selected from a fluorine-containing norbornene derivative having an acid-dissociable functional group Y ² that is dissociated by a —COOH group or an acid to change to a —COOH group. It is.

  The structural unit M2 is an arbitrary structural unit, but since it is a norbornene derivative similar to M1, it exhibits the same reactivity as M1, is excellent in copolymerizability, has an adjustable composition ratio, and has a functional group distribution. The point which can be made uniform in a polymer is excellent. Further, since M2 has a —COOH group having a high ability to dissolve in an alkaline developer, even if M2 is introduced into the polymer (A) in a small proportion, the polymer (A) can be dissolved in the alkaline developer. It is excellent in that the dissolution characteristics can be improved, and furthermore, a high solubility in an alkaline developer can be imparted to a resist composition using the same. However, since the —COOH group also has high hydrophilicity at the same time, there is a possibility that a poor pattern may be swollen during development and a good pattern may not be obtained. Therefore, in the polymer (A) of M2, The composition is preferably 45% or less.

Y ² is a -COOH group or an acid-dissociable functional group that is dissociated by an acid and changes to a -COOH group. Examples of the acid dissociable functional group that dissociates with an acid and changes to a —COOH group include a functional group represented by the formula: —COOQ ¹ (wherein Q ¹ is a protecting group).

Examples of the protecting group Q ¹ are the same as the protecting group P of M1.

  As the structural unit M2, the structural unit N2 described in the pamphlet of International Publication No. WO03 / 006413A1 is particularly represented by the formula (3) -1:

Wherein A, B and C are H or F; an alkyl group having 1 to 10 carbon atoms or a fluorinated alkyl group having 1 to 10 carbon atoms; R is a divalent hydrocarbon group having 1 to 20 carbon atoms, carbon is a 0 or an integer from 1 to 3; fluorinated alkylene group having an ether bond or a fluorine-containing alkylene group having 2-100 carbon atoms having 1 to 20 b is 0 or ^1; -COOQ 1 is -COOH group or an acid An acid dissociable functional group that can be converted into a —COOH group; provided that b is 0 or when R does not contain a fluorine atom, any one of A to C is a fluorine atom or a fluorine-containing alkyl group) A structural unit derived from a fluorine-containing norbornene derivative is preferable from the viewpoint that transparency can be further improved and developer solubility can be improved or adjusted.

  The structural unit M2 is particularly preferable because it can be synthesized at a low cost.

Wherein X ³ , X ⁴ and X ⁵ are the same or different, H, F or CF ₃ ; R ¹ is a divalent organic group having 1 to 20 carbon atoms; n1 is 0 or 1; Y ² is a formula The same as (M-1), at least one structural unit selected from structural units derived from norbornene derivatives represented by a —COOH group or an acid-dissociable functional group that can be converted to a —COOH group by an acid) is preferable.

  In particular,

Etc.

  The structural unit N1 which is also an arbitrary structural unit is a structural unit derived from the monomer (n1) copolymerizable with the monomer (m1) and / or the monomer (m2).

As a preferable unit of the structural unit N, a structural unit derived from an ethylenic monomer (n-1) having a carboxylic acid derivative (—COOQ ¹ ) in which a protecting group capable of dissociating with an acid is introduced into —COOH group or —COOH group. N-1 and may or may not contain a fluorine atom.

  Specifically, the formula (N-1):

(In the formula, COOQ ¹ is a —COOH group or a group in which an acid-dissociating protecting group is introduced into —COOH group; X ¹² and X ¹³ are the same or different; H or F; X ¹⁴ is H, F, Cl, CH; ₃ or CF ₃ ; X ¹⁵ and X ¹⁶ are the same or different, H, F or CF ₃ ; Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or an ether bond having 2 to 100 carbon atoms , A is an integer of 0 to 3; b, c and d are the same or different and include structural units represented by 0 or 1).

Among these, those not containing a fluorine atom (d = 0) are specifically acrylic monomers CH ₂ = CHCOOQ ¹ , CH ₂ = C (CH ₃ ) COOQ ¹ ,
CH ₂ = CClCOOQ ¹ ,
Maleic monomer

Allyl monomers CH ₂ = CHCH ₂ COOQ ¹ , CH ₂ = CHCH ₂ OCH ₂ CH ₂ COOQ ¹
Styrene monomer

Etc.

In addition, the main chain containing a fluorine atom (d = 0)
Fluorine-containing acrylic monomer CH ₂ = CFCOOQ ¹ , CH ₂ = C (CF ₃ ) COOQ ¹ ,
CF ₂ = CFCOOQ ¹ , CF ₂ = C (CF ₃ ) COOQ ¹
Fluorine-containing allyl monomer ^{_{CH 2 = CFCF 2 COOQ 1,}} CF 2 = CFCF 2 COOQ 1
CH ₂ = CHCF ₂ COOQ ¹
Fluorine-containing styrene monomer

Etc.

As having a fluoroalkyl group (d = 1) in the side chain,
Preferably formula (n-1a):
_{CH 2 = CFCF 2 O-Rf} -COOQ 1 (n-1a)
(Wherein, COOQ ¹ and Rf are the same as those in the above formula (N-1)),
In particular

Etc.

Also preferably formula (n-1b):
_{CF 2 = CFO-Rf-COOQ} 1 (n-1b)
(Wherein, COOQ ¹ and Rf are the same as those in the above formula (N-1)),
In particular

Etc.

Examples of other monomers (n-1) include CF ₂ = CFCF ₂ —O—Rf—COOQ ¹ , CF ₂ = CF—Rf—COOQ ¹ ,
_{CH 2 = CH-Rf-COOQ} 1, CH 2 = CHO-Rf-COOQ 1
(Rf is the same as Rf in formula (N-1))
And more specifically,

Etc.

Q ¹ in the ethylenic monomer (n-1) having the carboxylic acid derivative (—COOQ ¹ ) exemplified above is preferably the same as those exemplified above.

The structural unit derived from the monomer (n-1) exemplified above can be copolymerized with the monomers constituting the structural units M1 and M2, and can be further converted to -COOH group by -COOH group or acid. Since it has a functional functional group —COOQ ¹ , the introduction of these is preferable in that the function of further dissolving an aqueous alkali solution (developer) can be improved.

Further, as other ethylenic monomer (n-2) constituting the structural unit N,
Acrylic monomer (except for the monomer giving structural unit N-1):

Styrene monomer:

Ethylene monomer:
_{CH 2 = CH 2, CH 2} = CHCH 3, CH 2 = CHCl maleic acid monomer:

Allyl monomers:
Allyl ether monomers such as CH ₂ = CHCH ₂ Cl, CH ₂ = CHCH ₂ OH, CH ₂ = CHCH ₂ COOH, CH ₂ = CHCH ₂ Br, etc .:

Other monomers:

Norbornene derivatives not corresponding to M1 and M2:
Formula (n-3):

OH group-containing norbornene derivative represented by the formula (wherein Z is an oxygen atom or —CH ₂ O—; n4 is 0 or 1; Rf ¹ , Rf ² , R ² and n3 are the same as those in the formula (m1-1)) Can also be raised.

In the formula (n-3), Rf ¹ and Rf ² are preferably exemplified by those exemplified in the above formula (1).

  Specific examples of the OH group-containing norbornene derivative represented by the formula (n-3) include, for example,

(Wherein R ² , Rf ¹ , Rf ² and n3 are the same as in formula (n-3))
And more specifically,

Etc. are preferably mentioned.
Formula (n-4):

An OH group-containing norbornene derivative represented by the formula (wherein Rf ¹ , Rf ² , R ² , and n3 are the same as those in the formula (m1-1)) is also included.

In the formula (n-4), Rf ¹ and Rf ² are preferably the same as those exemplified in the above formula (1).

  Specific examples of the norbornene derivative represented by the formula (n-4) include, for example,

And more specifically,

Etc. are preferably mentioned.

In the formulas (n-3) and (n-4), Rf ¹ and Rf ² are preferably exemplified by those exemplified above for M1. In the formula (n-3), R ² is selected from H or an alkyl group having 1 to 10 carbon atoms, and may be the same or different. R ² is preferably H or a CH ₃ group, and H is particularly preferable.

  In addition, unsubstituted norbornene can be used.

  The selection of the stereoisomer of norbornene having an acid dissociable group introduced in the polymer (A) in the present invention is not particularly limited, but 80% or more of the stereostructure of norbornene having an acid dissociable group introduced is exo. From the viewpoint of the reactivity of the acid dissociable group, it is preferably 90% or more, more preferably 95% or more.

  The molecular weight of the polymer (A) in the present invention is 1000 to 100,000, preferably 2000 to 50000, more preferably 2000 to 10000 in terms of number average molecular weight, and 2000 to 200000, preferably 2000 to 50000, more preferably in terms of weight average molecular weight. Is 3000-20000.

  In the present invention, the polymer (A) is produced by (co) polymerizing (M1) or (M2) and, if necessary, the monomer (N1) by a known method to obtain the structure of each monomer. Produced by radical, cation, anionic polymerization, or addition polymerization of the corresponding unsaturated monomer. For example, the method described in Macromolecules 1996, 29, pp 2755-2863 is specifically shown, but it is preferable to produce the polymer under conditions suitable for each monomer and polymerization catalyst.

  Polymerization methods include solution polymerization in an organic solvent in which the monomer is dissolved, suspension polymerization in the presence or absence of an appropriate organic solvent in an aqueous medium, and adding an emulsifier to the aqueous medium. An emulsion polymerization method performed, a bulk polymerization method performed without a solvent, or the like can be used. Of these, solution polymerization and suspension polymerization using an organic solvent are preferred.

  The reaction temperature is appropriately selected in the range of −20 to 200 ° C., among them, 0 to 150 ° C., preferably 10 to 100 ° C. Furthermore, the reaction proceeds sufficiently at a temperature around room temperature (15 to 30 ° C.).

  Although it does not restrict | limit especially as a polymerization solvent, A hydrocarbon type solvent, a fluorine-type solvent (fluorocarbon type), a chlorine type solvent, an alcohol type solvent, a ketone type solvent, an acetic acid ester type solvent, an ether type solvent, etc. are used preferably. Specifically, methylene chloride, acetonitrile, tetrahydrofuran, nitrobenzene, chlorobenzene and the like are preferably used, and acetonitrile and tetrahydrofuran are more preferably used in terms of the solubility of the metal catalyst.

As the metal catalyst for the addition polymerization, a palladium catalyst, a nickel catalyst, and a platinum catalyst are preferably used. Specifically, (η ³ -C ₃ H ₅ ) Pd (SbF ₆ ), (η ³ -C ₃ H ₅ ) Pd (BF ₄ ), [Pd (CH ₃ CN) ₄ ] [BF ₄ ] _{2 and the} like. Is mentioned. Among them, (η ³ -C ₃ H ₅ ) Pd (SbF ₆ ) is preferable in terms of high reactivity, and Pd (CH ₃ CN) ₄ ] [BF ₄ ] ₂ is in that a polymer having a narrow molecular weight distribution can be obtained. preferable.

  The structural unit M2 having a —COOH group can impart high developer solubility, but at the same time has high hydrophilicity, so that during development, the resin in the underexposed part may swell and a good pattern may not be obtained. Therefore, these structural units M1, M2 and N1 are contained in the polymer (A) in which the structural unit M1 is 55 to 100 mol%, the structural unit M2 is 0 to 45 mol%, and the structural unit N1 is 0 to 20 mol%. %, M1 + M2 is 80 to 100 mol%, and the molar ratio of M1 / M2 is 55/45 to 100/0.

  Further, from the viewpoint of transparency, the fluorine-containing alcohol group is more transparent than the —COOH group, and therefore, the polymer (A) preferably has 70 to 100 mol% of the structural unit M1 and 0 of the structural unit M2 in the polymer (A). -30 mol%, structural unit N1 is 0-15 mol%, M1 + M2 is 85-100 mol%, and the molar ratio of M1 / M2 is 70 / 30-100 / 0, in particular, structural unit M1 is 80 ~ 100 mol%, structural unit M2 is 0 to 20 mol%, structural unit N1 is 0 to 10 mol%, M1 + M2 is 90 to 100 mol%, and the molar ratio of M1 / M2 is 80/20 ~ 100/0.

  The blending amount of the dissolution inhibitor (c) comprising the polymer (A) is such that the total weight of the acid dissociable functional group-containing polymer (a) and the dissolution inhibitor (c) is 100, and the acid dissociable functional group-containing polymer. It is preferable that the abundance ratio (a) / (c) between (a) and the dissolution inhibitor (c) is 30/70 to 99/1 by weight because the development characteristics are good. The abundance ratio (a) / (c) is more preferably 50/50 to 99/1, and even more preferably 70/30 to 99/1.

  In the OH group-containing fluoropolymer constituting the polymer (A) of the present invention, the moiety of the formula (1) bonded to carbon forming the ring structure of the structural unit derived from the OH group-containing norbornene derivative (M1 or M2) If attention is paid to an atomic group containing carboxylic acids, the three-dimensional structure can be distinguished into two types of stereoisomers, an endo type and an exo type.

  In the norbornene derivative, the functional group is bonded to either the endo-type or exo-type position, and the end-type has the formula (5A):

(Wherein PG is a moiety of the formula (1) or an atomic group containing a carboxylic acid; X ′ is selected from a hydrogen atom, a fluorine atom, and CF ₃ ), and has a moiety of the formula (1). The atomic group (PG) is located inside the norbornene skeleton, and the exo form is the formula (5B):

(Wherein, PG and X ′ are the same as above), the atomic group (PG) having the site of the formula (1) is located outside the norbornene skeleton, and the difference between these stereoisomers and The abundance ratio can be detected and quantitatively analyzed by, for example, ¹⁹ F-NMR.

  In the OH group-containing fluorine-containing polymer constituting the polymer (A) of the present invention, a resist composition using a fluorine-containing polymer having a structural unit derived from a protective group-containing norbornene derivative having a high exo-type ratio as a dissolution inhibitor. It is preferable to produce the fine pattern with high resolution. The preferred range is that, in the endo-exo stereoisomerism in the norbornene derivative in which a protecting group is introduced into the OH group, the exo form ratio is (Formula 1):

A structural unit derived from a protective group-containing norbornene derivative having a high exo-type ratio represented by Exo ratio:

The value of is preferably 95 mol% or more, more preferably 97 mol% or more, particularly preferably 99 mol% or more, and particularly preferably has an exo ratio of substantially 100 mol%. If the exo-type ratio is too low, the resolution is insufficient when forming a resist pattern, and therefore a more precise fine pattern cannot be obtained.

  Regarding the method of introducing the protecting group, it may be produced by selecting an appropriate polymerization catalyst at the time of polymerization and performing exo-selective polymerization, or by introducing a protecting group into a previously polymerized unprotected polymer. You can go.

  Examples of the acid-dissociable functional group-containing polymer (a) that is the base polymer of the resist composition of the present invention include conventionally known acid-dissociable functional group-containing polymers used in resist compositions for fine pattern formation. .

In particular, the acid-dissociable functional group-containing polymer (a) used in the present invention is preferably a polymer having an alicyclic hydrocarbon structure, and further has a light absorption coefficient of 193 nm wavelength (ArF excimer laser light) of 1.5 μm. ^-1 or less, more preferably 1.0 μm ⁻¹ or less, still more preferably 0.7 μm ⁻¹ or less, and particularly preferably 0.5 μm ⁻¹ or less, is the polymer (a) from the viewpoint of good development characteristics. The lower limit is most preferably close to zero.

  Specifically, polyacrylic acid ester, polymethacrylic acid ester, polysiloxane polymer, homopolymer such as polymer having fluorine-containing diene as monomer, acrylic acid monomer, methacrylic acid Two or more selected from monomers, styrene monomers, norbornene monomers, maleic monomers, vinyl ether monomers, allyl monomers, fluorine-containing ethylenic monomers, etc. Examples include copolymers obtained from monomers. These polymers may be used alone or in combination of two or more.

  Among these, it is obtained from two or more kinds of monomers selected from acrylic acid monomers, methacrylic acid monomers, norbornene monomers, maleic monomers, and fluorine-containing ethylenic monomers. Copolymers, polysiloxane polymers, polyacrylic acid esters, and polymethacrylic acid esters are preferred from the viewpoint of good development characteristics.

  Furthermore, polyacrylic acid ester, polymethacrylic acid ester, copolymer of acrylic acid monomer and methacrylic acid monomer, polysiloxane polymer, norbornene monomer and fluorine-containing ethylenic monomer These copolymers or their mixtures are particularly preferably selected because of their excellent dry etching resistance.

From the viewpoint of transparency, when an ArF laser is used, it is selected from acrylic monomers, methacrylic monomers, norbornene monomers, maleic monomers, and fluorine-containing ethylenic monomers. Preferred examples include copolymers obtained from two or more monomers, polyacrylic acid esters, polymethacrylic acid esters, polysiloxane polymers, and polymers containing fluorine-containing dienes as monomers. In the case of using an F ₂ laser, a polysiloxane polymer, a copolymer of a norbornene monomer and a fluorine-containing ethylenic monomer, and a polymer containing a fluorine-containing diene as a monomer are preferable.

  As a copolymer containing a structural unit derived from polyacrylic acid ester, polymethacrylic acid ester, acrylic acid monomer or methacrylic acid monomer used as a preferred alkali-soluble resin in the present invention, the following formula (1-1 ), (1-2) or those containing the structural unit represented by (1-3).

In Formula (1-1), Ra ¹ is a hydrogen atom or a methyl group, Z ^1a is a linear or branched divalent organic group or a divalent organic group having an alicyclic structure, and Ra ² is a hydrogen atom. Or it is a monovalent functional group.

In Formula (1-2), Ra ³ is a hydrogen atom or a methyl group, and each Ra ⁴ is independently a linear or branched alkyl group having 1 to 4 carbon atoms or a derivative thereof, or having 4 to 20 carbon atoms. A monovalent alicyclic hydrocarbon group or a derivative thereof, or any two Ra ⁴ 's bonded to each other, together with the carbon atoms to which each is bonded, together with the divalent fat having 4 to 20 carbon atoms A cyclic hydrocarbon group or a derivative thereof, and the remaining Ra ⁴ is a linear or branched alkyl group having 1 to ⁴ carbon atoms or a derivative thereof, or a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms Represents a group or a derivative thereof.

In Formula (1-3), Ra ⁵ is a hydrogen atom or a methyl group, Ra ⁶ is a linear or branched alkyl group having 1 to 12 carbon atoms, or a monovalent valence having 4 to 20 carbon atoms having an alicyclic structure. An organic group, a monovalent organic group having a cyclic ether structure, or a monovalent organic group having an optionally substituted lactone skeleton.

In the formula (1-1), examples of the linear or branched divalent organic group represented by Z ^1a include
A methylene group such as a methylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a 2-methyltrimethylene group, a hexamethylene group, an octamethylene group, a decamethylene group, or an alkylene group having 2 to 12 carbon atoms;
Fluoromethylene group, difluoromethylene group, fluoroethylene group, 1,1-difluoroethylene group, 1,2-difluoroethylene group, 1,2,2-trifluoroethylene group, 1,1,2,2-tetrafluoroethylene A fluorinated methylene group such as a group, a trifluoromethylethylene group or a 1,1-di (trifluoromethyl) ethylene group, or a fluorinated alkylene group having 2 to 12 carbon atoms.

Examples of the divalent organic group having an alicyclic structure of Z ^1a include groups derived from cycloalkanes having 4 to 20 carbon atoms such as cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane; adamantane , Bicyclo [2.2.1] heptane, tetracyclo [6.2.1.1 ^3,6 . And groups derived from bridged hydrocarbons having 4 to 20 carbon atoms such as 0 ^2,7 ] dodecane and tricyclo [5.2.1.0 ^2,6 ] decane.

The Z ^1a in the general formula (1-1), a methylene group, an ethylene group, a divalent group derived from adamantane, etc. divalent group derived from a bicyclo [2.2.1] heptane is preferable.

In the general formula (1-1), examples of the monovalent functional group of Ra ² include a hydroxyl group, a carboxyl group, a nitro group, a cyano group, and an amino group.
Ra ² in the general formula (1-1) is preferably a hydrogen atom, a hydroxyl group, a carboxyl group, a cyano group, or the like.

In the general formula (1-1), preferred examples of the —Z ^1a -Ra ² group include a hydroxymethyl group, a 2-hydroxyethyl group, a 3-hydroxypropyl group, 4- (2,2,2-trifluoro-), 1-hydroxy-1-trifluoromethyl-ethyl) -cyclohexyl group, 3-hydroxyadamantan-1-yl group, 5-hydroxybicyclo [2.2.1] heptan-2-yl group, 6-hydroxybicyclo [2 2.1] heptan-2-yl group, 9-hydroxytetracyclo [6.2.1.1 ^3,6 . 0 ^2,7] dodecane-4-yl group, 10-hydroxy-tetracyclo [6.2.1.1 ^{3, 6.} 0 ^2,7 ] dodecan-4-yl group, carboxymethyl group, 2-carboxyethyl group, 3-carboxypropyl group, 3-carboxyadamantan-1-yl group, 5-carboxybicyclo [2.2.1] heptane 2-yl group, 6-carboxybicyclo [2.2.1] heptan-2-yl group, 9-carboxytetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 10-carboxytetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, cyanomethyl group, 2-cyanoethyl group, 3-cyanopropyl group, 3-cyanoadamantan-1-yl group, 5-cyanobicyclo [2.2.1] heptane-2 -Yl group, 6-cyanobicyclo [2.2.1] heptan-2-yl group, 9-cyanotetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 10-cyanotetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group and the like.

In the general formula (1-2), the alkyl group or derivative thereof linear or branched having 1 to 4 carbon atoms Ra ^4, for example, a methyl group, an ethyl group, n- propyl group, i- propyl , N-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like. Of these alkyl groups, a methyl group, an ethyl group, and the like are preferable.

  Examples of the derivative of the alkyl group include, for example, hydroxyl group; carboxyl group; oxo group (that is, ═O group); hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, C1-C6 hydroxyalkyl groups such as 2-hydroxypropyl group, 3-hydroxypropyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group; methoxy group, ethoxy group, n-propoxy Group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1-methylpropoxy group, t-butoxy group and the like, alkoxy group having 1 to 6 carbon atoms; cyano group; cyanomethyl group, 2-cyanoethyl group, C2-C6 cyanoalkyl group such as 3-cyanopropyl group, 4-cyanobutyl group, etc. Substituent can be exemplified one or more or one or more a group having.

  Of these substituents, an oxo group, a hydroxyalkyl group, an alkoxyl group, and the like are preferable, and an oxo group, a hydroxymethyl group, a 1-hydroxyethyl group, a methoxy group, an ethoxy group, and the like are particularly preferable.

Also, having 4 to 20 carbon atoms in Ra ⁴ 1 valent alicyclic hydrocarbon group and any two of Ra ⁴ number 4 to 20 carbon formed together with the carbon atom to which each bonded to each other are attached Examples of the divalent alicyclic hydrocarbon group include cycloalkanes such as cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane, adamantane, bicyclo [2.2.1] heptane, and tetracyclo [6.2. 1.1 ^3,6 . Groups derived from bridged hydrocarbons such as 0 ^2,7 ] dodecane, tricyclo [5.2.1.0 ^2,6 ] decane; groups derived from these cycloalkanes or bridged hydrocarbons A linear group having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, Examples thereof include a group substituted with one or more branched or cyclic alkyl groups.

  Examples of the derivative of the monovalent or divalent alicyclic hydrocarbon group include a hydroxyl group; a carboxyl group; an oxo group (that is, ═O group); a hydroxymethyl group, a 1-hydroxyethyl group, and 2- C1-C4 hydroxyalkyl groups such as hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group An alkoxyl group having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, a 2-methylpropoxy group, a 1-methylpropoxy group and a t-butoxy group; Group: C2-C2 such as cyanomethyl group, 2-cyanoethyl group, 3-cyanopropyl group, 4-cyanobutyl group, etc. It can be mentioned one or more, or one or more a group having a substituent such as a cyano group.

  Of these substituents, a hydroxyl group, a carboxyl group, a hydroxymethyl group, a cyano group, a cyanomethyl group, and the like are preferable.

In the general formula (1-2), a preferred structure, at least one of Ra ⁴ corresponds to -C (Ra ⁴⁾ ₃ where a monovalent alicyclic hydrocarbon group or a derivative thereof having 4 to 20 carbon atoms Examples thereof include groups represented by the following formulas (1-2a) to (1-2d).

  In Formula (1-2c) and Formula (1-2d), a and b are integers of 0 to 2, respectively.

In addition, when any two Ra ⁴ are bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof together with the carbon atom to which each is bonded, —C (Ra ⁴ ) Preferred examples of the structure corresponding to ₃ include groups represented by the following formulas (1-2e) to (1-2h).

  In Formula (1-2g) and Formula (1-2h), a and b are each an integer of 0 to 2.

In the general formula (1-2), as a preferred -C (Ra ⁴ ) ₃ group, for example,
t-butyl group, 2-methyl-2-butyl group, 2-ethyl-2-butyl group, 3-methyl-3-butyl group, 3-ethyl-3-butyl group, 3-methyl-3-pentyl group, etc. A trialkylmethyl group of
1-alkyl cycloalkyl groups such as 1-methylcyclopentyl group, 1-ethylcyclopentyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group;
2-methyladamantan-2-yl group, 2-methyl-3-hydroxyadamantan-2-yl group, 2-methyl-3-cyanoadamantan-2-yl group, 2-ethyladamantan-2-yl group, 2- Ethyl-3-hydroxyadamantan-2-yl group, 2-ethyl-3-cyanoadamantan-2-yl group,
2-methylbicyclo [2.2.1] heptan-2-yl group, 2-methyl-5-hydroxybicyclo [2.2.1] heptan-2-yl group, 2-methyl-6-hydroxybicyclo [2] 2.1] heptane-2-yl group, 2-methyl-5-cyanobicyclo [2.2.1] heptan-2-yl group, 2-methyl-6-cyanobicyclo [2.2.1] heptane 2-yl group, 2-ethylbicyclo [2.2.1] heptan-2-yl group, 2-ethyl-5-hydroxybicyclo [2.2.1] heptan-2-yl group, 2-ethyl- 6-hydroxybicyclo [2.2.1] heptan-2-yl group, 2-ethyl-5-cyanobicyclo [2.2.1] heptan-2-yl group, 2-ethyl-6-cyanobicyclo [2] 2.1] heptan-2-yl group, 4-methylteto Cyclo [6.2.1.1 ^3,6. 0 ^2,7 ] dodecan-4-yl group, 4-methyl-9-hydroxytetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 4-methyl-10-hydroxytetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 4-methyl-9-cyanotetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 4-methyl-10-cyanotetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 4-ethyltetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 4-ethyl-9-hydroxytetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 4-ethyl-10-hydroxytetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 4-ethyl-9-cyanotetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 4-ethyl-10-cyanotetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 8-methyltricyclo [5.2.1.0 ^2,6 ] decan-8-yl group, 8-methyl-4-hydroxytricyclo [5.2. 1.0 ^2,6 ] decan-8-yl group, 8-methyl-4-cyanotricyclo [5.2.1.0 ^2,6 ] decan-8-yl group, 8-ethyltricyclo [5. 2.1.0 ^2,6 ] decan-8-yl group, 8-ethyl-4-hydroxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl group, 8-ethyl-4- Alkyl-substituted bridged hydrocarbon groups such as cyanotricyclo [5.2.1.0 ^2,6 ] decan-8-yl group and derivatives thereof;
1-methyl-1-cyclopentylethyl group, 1-methyl-1- (2-hydroxycyclopentyl) ethyl group, 1-methyl-1- (3-hydroxycyclopentyl) ethyl group, 1-methyl-1- (2-cyano Cyclopentyl) ethyl group, 1-methyl-1- (3-cyanocyclopentyl) ethyl group, 1-methyl-1-cyclohexylethyl group, 1-methyl-1- (3-hydroxycyclohexyl) ethyl group, 1-methyl-1 -(4-hydroxycyclohexyl) ethyl group, 1-methyl-1- (3-cyanocyclohexyl) ethyl group, 1-methyl-1- (4-cyanocyclohexyl) ethyl group, 1-methyl-1-cycloheptylethyl group 1-methyl-1- (3-hydroxycycloheptyl) ethyl group, 1-methyl-1- (4-hydroxycyclohe Chill) ethyl group, 1-methyl-1- (3-Shianoshikuro heptyl) ethyl group, a dialkyl-cycloalkylmethyl groups and derivatives thereof such as 1-methyl-1- (heptyl to 4 Shianoshikuro) ethyl group;
1-methyl-1- (adamantan-1-yl) ethyl group, 1-methyl-1- (3-hydroxyadamantan-1-yl) ethyl group, 1-methyl-1- (3-cyanoadamantan-1-yl ) Ethyl group, 1-methyl-1- (bicyclo [2.2.1] heptan-2-yl) ethyl group, 1-methyl-1- (5-hydroxybicyclo [2.2.1] heptane-2- Yl) ethyl group, 1-methyl-1- (6-hydroxybicyclo [2.2.1] heptan-2-yl) ethyl group, 1-methyl-1- (5-cyanobicyclo [2.2.1] Heptan-2-yl) ethyl group, 1-methyl-1- (6-cyanobicyclo [2.2.1] heptan-2-yl) ethyl group, 1-methyl-1- (tetracyclo [6.2.1] .1 ^3,6 .0 ^2,7] dodecane-4-yl) ethyl group, 1-methyl-1- (9-hydroxytetracyclo [6.2.1.1 ^3,6 .0 ^2,7 ] dodecan-4-yl) ethyl group, 1-methyl-1- (10-hydroxytetracyclo [6.2.1.1 ^3,6 .0 ^2,7 ] dodecan-4-yl) ethyl group, 1-methyl-1- (9-cyanotetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl) ethyl group, 1-methyl-1- (10-cyanotetracyclo [6.2.1.1 ^3,6 0.0 ^2,7 ] dodecan-4-yl) ethyl Group, 1-methyl-1- (tricyclo [5.2.1.0 ^2,6 ] decan-8-yl) ethyl group, 1-methyl-1- (4-hydroxytricyclo [5.2.1. 0 ^2,6 ] decan-8-yl) ethyl group, 1-methyl-1- (4-cyanotricyclo [5.2.1.0 ^2,6 ] decan-8-yl) ethyl group, etc. Alkyl-substituted and bridged hydrocarbon-substituted methyl groups and derivatives thereof;
1,1-dicyclopentylethyl group, 1,1-di (2-hydroxycyclopentyl) ethyl group, 1,1-di (3-hydroxycyclopentyl) ethyl group, 1,1-di (2-cyanocyclopentyl) ethyl group 1,1-di (3-cyanocyclopentyl) ethyl group, 1,1-dicyclohexylethyl group, 1,1-di (3-hydroxycyclohexyl) ethyl group, 1,1-di (4-hydroxycyclohexyl) ethyl group 1,1-di (3-cyanocyclohexyl) ethyl group, 1,1-di (4-cyanocyclohexyl) ethyl group, 1,1-dicycloheptylethyl group, 1,1-di (3-hydroxycycloheptyl) ) Ethyl group, 1,1-di (4-hydroxycycloheptyl) ethyl group, 1,1-di (3-cyanocycloheptyl) ethyl group, 1,1-di ( - alkyl di cycloalkylmethyl group and derivatives thereof, such as heptyl) ethyl group to Shianoshikuro;
1,1-di (adamantan-1-yl) ethyl group, 1,1-di (3-hydroxyadamantan-1-yl) ethyl group, 1,1-di (3-cyanoadamantan-1-yl) ethyl group 1,1-di (bicyclo [2.2.1] heptan-2-yl) ethyl group, 1,1-di (5-hydroxybicyclo [2.2.1] heptan-2-yl) ethyl group, 1,1-di (6-hydroxybicyclo [2.2.1] heptan-2-yl) ethyl group, 1,1-di (5-cyanobicyclo [2.2.1] heptan-2-yl) ethyl Group, 1,1-di (6-cyanobicyclo [2.2.1] heptan-2-yl) ethyl group, 1,1-di (tetracyclo [6.2.1.1 ^3,6 .0 ^{2, 7} ] dodecan-4-yl) ethyl group, 1,1-di (9-hydroxytetracyclo [6.2.1.1]. ^3,6 .0 ^2,7 ] dodecan-4-yl) ethyl group, 1,1-di (10-hydroxytetracyclo [6.2.1.1 ^3,6 .0 ^2,7 ] dodecan-4- yl) ethyl group, 1,1-di (9-cyano-tetracyclo [6.2.1.1 ^3,6 .0 ^2,7] dodecane-4-yl) ethyl group, 1,1-di (10- Cyanotetracyclo [6.2.1.1 ^3,6 .0 ^2,7 ] dodecan-4-yl) ethyl group, 1,1-di (tricyclo [5.2.1.0 ^2,6 ] decane- 8-yl) ethyl group, 1,1-di (4-hydroxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl) ethyl group, 1,1-di (4-cyanotricyclo Examples include [5.2.1.0 ^2,6 ] 8-yl) ethyl-substituted alkyl-substituted / di- (bridged hydrocarbon group) -substituted methyl group and derivatives thereof.

Of these —C (Ra ⁴ ) ₃ groups, t-butyl group, 2-methyl-2-butyl group, 2-ethyl-2-butyl group, 3-ethyl-3-butyl group are particularly preferable. 1-methylcyclopentyl group, 1-ethylcyclopentyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, 2-methyladamantan-2-yl group, 2-methyl-3-hydroxyadamantan-2-yl group, 2 -Ethyladamantan-2-yl group, 2-methylbicyclo [2.2.1] heptan-2-yl group, 2-ethylbicyclo [2.2.1] heptan-2-yl group, 4-methyltetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 4-ethyltetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 8-methyltricyclo [5.2.1.0 ^2,6 ] -8-yl group, 8-ethyltricyclo [5.2.1.0 ^{2, 6} ] -8-yl group, 1-methyl-1-cyclopentylethyl group, 1-methyl-1- (2-hydroxycyclopentyl) ethyl group, 1-methyl-1- (3-hydroxycyclopentyl) ethyl group, 1- Methyl-1-cyclohexylethyl group, 1-methyl-1- (3-hydroxycyclohexyl) ethyl group, 1-methyl-1- (4-hydroxycyclohexyl) ethyl group, 1-methyl-1-cycloheptylethyl group, 1 -Methyl-1- (3-hydroxycycloheptyl) ethyl group, 1-methyl-1- (4-hydroxycycloheptyl) ethyl group, 1-methyl-1- (adamantan-1-yl) ethyl group, 1 −Me Ru-1- (3-hydroxyadamantan-1-yl) ethyl group, 1-methyl-1- (bicyclo [2.2.1] heptan-2-yl) ethyl group, 1-methyl-1- (tetracyclo [ 6.2.1.1 ^3,6 .0 ^2,7 ] dodecan-4-yl) ethyl group, 1-methyl-1- (tricyclo [5.2.1.0 ^2,6 ] -8-yl) Ethyl group, 1,1-dicyclopentylethyl group, 1,1-dicyclohexylethyl group, 1,1-di (adamantan-1-yl) ethyl group, 1,1-di (bicyclo [2.2.1] heptane -2-yl) ethyl group, 1,1-di (tetracyclo [6.2.1.1 ^3,6 .0 ^2,7 ] dodecan-4-yl) ethyl group, 1,1-di (tricyclo [5 And 2.1.0 ^2,6 ] -8-yl) ethyl group.

In the general formula (1-3), examples of the linear or branched alkyl group having 1 to 12 carbon atoms represented by Ra ⁶ include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n- A butyl group, a 2-methylpropyl group, a 1-methylpropyl group, a t-butyl group, and the like can be given.

Examples of the monovalent organic group having 4 to 20 carbon atoms having an alicyclic structure of Ra ⁶ include groups derived from cycloalkanes derived from cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane and the like. Adamantane, bicyclo [2.2.1] heptane, tetracyclo [6.2.1.1 ^3,6 . Groups derived from bridged hydrocarbons such as 0 ^2,7 ] dodecane, tricyclo [5.2.1.0 ^2,6 ] decane; groups derived from these cycloalkanes or bridged hydrocarbons A linear group having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, A group substituted with one or more of branched or cyclic alkyl groups; a monovalent group derived from cycloalkanes or bridged hydrocarbons which may be substituted with these alkyl groups is a hydroxyl group Carboxyl group; oxo group (that is, ═O group); hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropoxy; A hydroxyalkyl group having 1 to 4 carbon atoms such as a ruthel group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group; methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n- C1-C4 alkoxyl groups such as butoxy, 2-methylpropoxy, 1-methylpropoxy, t-butoxy; cyano; cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 4-cyanobutyl Examples thereof include a group substituted with one or more, such as a cyanoalkyl group having 2 to 5 carbon atoms, such as a group.

Examples of the monovalent organic group having a cyclic ether structure of Ra ⁶ include (tetrahydrofuran-2-yl) methyl group, (tetrahydropyran-2-yl) methyl group, and the like.

Examples of the monovalent organic group having an optionally substituted lactone skeleton of Ra ⁶ include groups represented by the following formulas (1-3a) to (1-3d).

In formulas (1-3a) and (1-3b), each Ra ⁸ is independently a hydrogen atom, a linear or branched alkyl group having 1 to 5 carbon atoms, or a linear chain having 1 to 5 carbon atoms. Z ³ represents a methylene group, a dimethylmethylene group, an oxygen atom or a sulfur atom, and represents a linear or branched alkoxyl group or a linear or branched alkoxycarbonyl group having 2 to 5 carbon atoms.

In Formula (1-3c), Ra ⁹ is a hydrogen atom, a linear or branched alkyl group having 1 to 5 carbon atoms, a linear or branched alkoxyl group having 1 to 5 carbon atoms, or 2 carbon atoms. -5 linear or branched alkoxycarbonyl groups.

In Formula (1-3d), Ra ¹⁰ represents a hydrogen atom, a linear or branched alkyl group having 1 to 5 carbon atoms, a linear or branched alkoxyl group having 1 to 5 carbon atoms, or 2 carbon atoms. Represents a linear or branched alkoxycarbonyl group of -5, a plurality of Ra ¹⁰ may be the same or different from each other, c is an integer of 0 to 4, and Z ⁴ represents a single bond or a methylene group. Show.

In the formulas (1-3a) to (1-3d), examples of the linear or branched alkyl group having 1 to 5 carbon atoms of Ra ⁸ , Ra ⁹ and Ra ¹⁰ include, for example, a methyl group, an ethyl group, n -Propyl group, i-propyl group, n-butyl group, 1-methylpropyl group, 2-methylpropyl group, t-butyl group, n-pentyl group and the like can be mentioned.

Examples of the linear or branched alkoxyl group having 1 to 5 carbon atoms of Ra ⁸ , Ra ⁹ and Ra ¹⁰ include, for example, a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, and n-butoxy. Group, 1-methylpropoxy group, 2-methylpropoxy group, t-butoxy group, n-pentyloxy group and the like.

Examples of the linear or branched alkoxycarbonyl group having 2 to 5 carbon atoms of Ra ⁸ , Ra ⁹ and Ra ¹⁰ include, for example, a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, and i-propoxycarbonyl. Group, n-butoxycarbonyl group, 1-methylpropoxycarbonyl group, 2-methylpropoxycarbonyl group, t-butoxycarbonyl group and the like.

In the general formula (1-3), as preferable Ra ⁶ , for example,
A linear or branched alkyl group such as a methyl group, an ethyl group or an n-propyl group; a cycloalkyl group such as a cyclopentyl group or a cyclohexyl group;
Adamantan-1-yl group, bicyclo [2.2.1] heptan-2-yl group, 7,7-dimethylbicyclo [2.2.1] heptan-1-yl group, tetracyclo [6.2.1. 1 ^3,6 . A group derived from a bridged hydrocarbon such as 0 ^2,7 ] dodecan-4-yl group, tricyclo [5.2.1.0 ^2,6 ] decan-8-yl group;
A monovalent organic group having a cyclic ether structure such as (tetrahydrofuran-2-yl) methyl group and (tetrahydropyran-2-yl) methyl group;
5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yl group, 9-methoxycarbonyl-5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yl group, 7-oxo-6-oxabicyclo [3.2.1] octane-4-yl group, 2-methoxycarbonyl-7-oxo-6-oxa-bicyclo [3. 2.1] Octane-4-yl group, 2-oxotetrahydropyran-4-yl group, 4-methyl-2-oxotetrahydropyran-4-yl group, 4-ethyl-2-oxotetrahydropyran-4-yl Group, 4-n-propyl-2-oxotetrahydropyran-4-yl group, 5-oxotetrahydrofuran-3-yl group, 2,2-dimethyl-5-oxotetrahydrofuran-3-yl group, 4,4-dimethyl -5-Oki So-tetrahydrofuran-3-yl group, 2-oxotetrahydrofuran-3-yl group, 4,4-dimethyl-2-oxotetrahydrofuran-3-yl group, 5,5-dimethyl-2-oxotetrahydrofuran-3-yl group, 2-oxotetrahydrofuran-3-yl group, (5-oxotetrahydrofuran-2-yl) methyl group, (3,3-dimethyl-5-oxotetrahydrofuran-2-yl) methyl group, (4,4-dimethyl-5 And an organic group having an optionally substituted lactone skeleton such as -oxotetrahydrofuran-2-yl) methyl group.

  In the alkali-soluble resin, the (meth) acrylic structural unit may be present alone or in combination of two or more.

  Examples of the copolymer containing a structural unit derived from a norbornene monomer include those having a structural unit represented by the following formula (2-1), (2-2), or (2-3).

In Formula (2-1), Z ² represents a single bond, a linear or branched divalent organic group, or a divalent organic group having an alicyclic structure, and Ra ¹¹ represents a hydrogen atom or a monovalent group. N is an integer of 0-2.

In formula (2-2), each Ra ¹² is independently a linear or branched alkyl group having 1 to 4 carbon atoms or a derivative thereof, or a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms. or a group or its derivative, or any two of Ra ¹² are bonded to each other together with the carbon atom to which each is attached, a divalent alicyclic hydrocarbon group or a derivative thereof having 4 to 20 carbon atoms The remaining Ra ¹² represents a linear or branched alkyl group having 1 to 4 carbon atoms or a derivative thereof, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, and n Is an integer of 0-2.

In the formula (2-3), Ra ¹³ has a linear or branched alkyl group having 1 to 12 carbon atoms, a monovalent organic group having 4 to 20 carbon atoms having an alicyclic structure, and a cyclic ether structure. A monovalent organic group or a monovalent organic group having an optionally substituted lactone skeleton is shown, and n is an integer of 0 to 2. ]
In the formula (2-1), examples of the linear or branched divalent organic group for Z ² include:
A methylene group such as a methylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a 2-methyltrimethylene group, a hexamethylene group, an octamethylene group, a decamethylene group, or an alkylene group having 2 to 12 carbon atoms;
Fluoromethylene group, difluoromethylene group, fluoroethylene group, 1,1-difluoroethylene group, 1,2-difluoroethylene group, 1,2,2-trifluoroethylene group, 1,1,2,2-tetrafluoroethylene A fluorinated methylene group such as a group, a trifluoromethylethylene group or a 1,1-di (trifluoromethyl) ethylene group, or a fluorinated alkylene group having 2 to 12 carbon atoms.

Examples of the divalent organic group having an alicyclic structure of Z ² include groups derived from cycloalkanes having 4 to 20 carbon atoms such as cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane; adamantane , Bicyclo [2.2.1] heptane, tetracyclo [6.2.1.1 ^3,6 . And groups derived from bridged hydrocarbons having 4 to 20 carbon atoms such as 0 ^2,7 ] dodecane and tricyclo [5.2.1.0 ^2,6 ] decane.

Z ² in the formula (2-1) is derived from a single bond, a methylene group, an ethylene group, a difluoromethylene group, a 1,2-difluoroethylene group, a 1,1,2,2-tetrafluoroethylene group, or an adamantane. A divalent group, a divalent group derived from bicyclo [2.2.1] heptane, and the like are preferable.

In the formula (2-1), examples of the monovalent functional group of Ra ¹¹ include a hydroxyl group, a carboxyl group, a nitro group, a cyano group, and an amino group.

Ra ¹¹ in Formula (2-1) is preferably a hydrogen atom, a hydroxyl group, a carboxyl group, a cyano group, or the like.

In the formula (2-1), preferred examples of the —Z ² —R ⁵ group include a hydrogen atom, a hydroxyl group, a hydroxymethyl group, a 2-hydroxyethyl group, a 3-hydroxypropyl group, and (fluoro) (hydroxy) methyl. Group, (difluoro) (hydroxy) methyl group, 1,2-difluoro-2-hydroxyethyl group, 1,1,2,2-tetrafluoro-2-hydroxyethyl group, 2-trifluoromethyl-2-hydroxyethyl Group, 2,2-di (trifluoromethyl) -2-hydroxyethyl group, 3-hydroxyadamantan-1-yl group, 5-hydroxybicyclo [2.2.1] heptan-2-yl group, 6-hydroxy Bicyclo [2.2.1] heptan-2-yl group, 9-hydroxytetracyclo [6.2.1.1 ^3,6 . 0 ^2,7] dodecane-4-yl group, 10-hydroxy-tetracyclo [6.2.1.1 ^{3, 6.} 0 ^2,7 ] dodecan-4-yl group, carboxyl group, carboxymethyl group, 2-carboxyethyl group, 3-carboxypropyl group, 3-carboxyadamantan-1-yl group, 5-carboxybicyclo [2.2. 1] heptan-2-yl group, 6-carboxy bicyclo [2.2.1] heptan-2-yl group, 9-carboxy-tetracyclo [6.2.1.1 ^{3, 6.} 0 ^2,7 ] dodecan-4-yl group, 10-carboxytetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, cyano group, cyanomethyl group, 2-cyanoethyl group, 3-cyanopropyl group, 3-cyanoadamantan-1-yl group, 5-cyanobicyclo [2.2.1] Heptan-2-yl group, 6-cyanobicyclo [2.2.1] heptan-2-yl group, 9-cyanotetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 10-cyanotetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group and the like.

In the formula (2-2), examples of the linear or branched alkyl group of 1 to 4 of Ra ¹² include, for example, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, A 2-methylpropyl group, a 1-methylpropyl group, a t-butyl group, and the like can be given.
Of these alkyl groups, a methyl group, an ethyl group, and the like are preferable.

  Examples of the derivative of the alkyl group include hydroxyl group; carboxyl group; oxo group (that is, ═O group); hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, C1-C6 hydroxyalkyl groups such as 2-hydroxypropyl group, 3-hydroxypropyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group; methoxy group, ethoxy group, n-propoxy Group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1-methylpropoxy group, t-butoxy group and the like, alkoxy group having 1 to 6 carbon atoms; cyano group; cyanomethyl group, 2-cyanoethyl group, C2-C6 cyanoalkyl groups such as 3-cyanopropyl group and 4-cyanobutyl group It can be mentioned substituents one or more or one or more having groups.

  Of these substituents, an oxo group, a hydroxyalkyl group, an alkoxyl group, and the like are preferable, and an oxo group, a hydroxymethyl group, a 1-hydroxyethyl group, a methoxy group, an ethoxy group, and the like are particularly preferable.

In addition, the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms of Ra ¹² and any two Ra ¹² bonded to each other to form a carbon atom having 4 to 20 carbon atoms formed together with the bonded carbon atoms. Examples of the divalent alicyclic hydrocarbon group include cycloalkanes such as cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane, adamantane, bicyclo [2.2.1] heptane, and tetracyclo [6.2. 1.1 ^3,6 . Groups derived from bridged hydrocarbons such as 0 ^2,7 ] dodecane, tricyclo [5.2.1.0 ^2,6 ] decane; groups derived from these cycloalkanes or bridged hydrocarbons A linear group having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, Examples thereof include a group substituted with one or more branched or cyclic alkyl groups.

  Examples of the derivative of the monovalent or divalent alicyclic hydrocarbon group include a hydroxyl group; a carboxyl group; an oxo group (that is, ═O group); a hydroxymethyl group, a 1-hydroxyethyl group, and 2- C1-C4 hydroxyalkyl groups such as hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group An alkoxyl group having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, a 2-methylpropoxy group, a 1-methylpropoxy group and a t-butoxy group; Group: C2-C2 such as cyanomethyl group, 2-cyanoethyl group, 3-cyanopropyl group, 4-cyanobutyl group, etc. It can be mentioned one or more or one or more a group having a substituent such as a cyano group.

  Of these substituents, a hydroxyl group, a carboxyl group, a hydroxymethyl group, a cyano group, a cyanomethyl group, and the like are preferable.

In the formula (2-2), as preferred —C (Ra ¹² ) ₃ group when at least one R ⁶ is a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, for example, Examples thereof include groups in which Ra ⁴ is converted to Ra ¹² in the formulas (1-2a) to (1-2d).

In addition, when any two R ⁶ are bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof together with the carbon atom to which each R ⁶ is bonded, —C Examples of the (Ra ¹² ) ₃ group include groups obtained by converting Ra ⁴ to Ra ¹² in the formulas (1-2e) to (1-2h).

In the formula (2-2), examples of the preferred —C (Ra ¹² ) ₃ group include the same groups as those exemplified as the preferred —C (Ra ⁴ ) ₃ group in the formula (1-2). Can do.

Of these —C (Ra ¹² ) ₃ groups, t-butyl group, 2-methyl-2-butyl group, 2-ethyl-2-butyl group, 3-ethyl-3-butyl group are particularly preferable. 1-methylcyclopentyl group, 1-ethylcyclopentyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, 2-methyladamantan-2-yl group, 2-methyl-3-hydroxyadamantan-2-yl group, 2 -Ethyladamantan-2-yl group, 2-methylbicyclo [2.2.1] heptan-2-yl group, 2-ethylbicyclo [2.2.1] heptan-2-yl group, 4-methyltetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 4-ethyltetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl group, 8-methyltricyclo [5.2.1.0 ^2,6 ] -8-yl group, 8-ethyltricyclo [5.2.1.0 ^{2, 6} ] -8-yl group, 1-methyl-1-cyclopentylethyl group, 1-methyl-1- (2-hydroxycyclopentyl) ethyl group, 1-methyl-1- (3-hydroxycyclopentyl) ethyl group, 1- Methyl-1-cyclohexylethyl group, 1-methyl-1- (3-hydroxycyclohexyl) ethyl group, 1-methyl-1- (4-hydroxycyclohexyl) ethyl group, 1-methyl-1-cycloheptylethyl group, 1 -Methyl-1- (3-hydroxycycloheptyl) ethyl group, 1-methyl-1- (4-hydroxycycloheptyl) ethyl group, 1-methyl-1- (adamantan-1-yl) ethyl group, 1 −Me Ru-1- (3-hydroxyadamantan-1-yl) ethyl group, 1-methyl-1- (bicyclo [2.2.1] heptan-2-yl) ethyl group, 1-methyl-1- (tetracyclo [ 6.2.1.1 ^3,6 .0 ^2,7 ] dodecan-4-yl) ethyl group, 1-methyl-1- (tricyclo [5.2.1.0 ^2,6 ] -8-yl) Ethyl group, 1,1-dicyclopentylethyl group, 1,1-dicyclohexylethyl group, 1,1-di (adamantan-1-yl) ethyl group, 1,1-di (bicyclo [2.2.1] heptane -2-yl) ethyl group, 1,1-di (tetracyclo [6.2.1.1 ^3,6 .0 ^2,7 ] dodecan-4-yl) ethyl group, 1,1-di (tricyclo [5 And 2.1.0 ^2,6 ] -8-yl) ethyl group.

In formula (2-3), examples of the linear or branched alkyl group having 1 to 12 carbon atoms represented by Ra ¹³ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and n-butyl. Group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like.

Examples of the monovalent organic group having 4 to 20 carbon atoms having an alicyclic structure of Ra ¹³ include groups derived from cycloalkanes derived from cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane and the like. Adamantane, bicyclo [2.2.1] heptane, tetracyclo [6.2.1.1 ^3,6 . Groups derived from bridged hydrocarbons such as 0 ^2,7 ] dodecane, tricyclo [5.2.1.0 ^2,6 ] decane; groups derived from these cycloalkanes or bridged hydrocarbons A linear group having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, A group substituted by one or more of branched or cyclic alkyl groups; a monovalent group derived from cycloalkanes or bridged hydrocarbons which may be substituted by these alkyl groups is a hydroxyl group Carboxyl group; oxo group (that is, ═O group); hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropoxy; A hydroxyalkyl group having 1 to 4 carbon atoms such as a ruthel group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group; methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n- C1-C4 alkoxyl groups such as butoxy, 2-methylpropoxy, 1-methylpropoxy, t-butoxy; cyano; cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 4-cyanobutyl Examples thereof include a group substituted with one or more, such as a cyanoalkyl group having 2 to 5 carbon atoms, such as a group.

Examples of the monovalent organic group having a cyclic ether structure of Ra ¹³ include (tetrahydrofuran-2-yl) methyl group, (tetrahydropyran-2-yl) methyl group, and the like.

Examples of the monovalent organic group having an optionally substituted lactone skeleton of Ra ¹³ include groups represented by the above formulas (1-3a) to (1-3d).

  Furthermore, the structural unit M1 derived from the fluorine-containing norbornene derivative used with the said dissolution inhibitor (c) can also be illustrated.

  In the alkali-soluble resin, the norbornene-based structural unit can be present alone or in combination of two or more.

  Preferred polysiloxane polymers in the present invention include polymers represented by the following general formula.

(Ra ¹⁴ and Ra ¹⁵ are hydrocarbon groups optionally having a fluorine atom having a functional group)

  Examples of the polymer having a fluorine-containing diene as a monomer include a repeating unit exemplified below and a polymer having a repeating unit in which an alcohol moiety is protected with an acid-dissociable functional group.

  Examples of the copolymer containing a structural unit derived from a styrene monomer include those having a structural unit derived from a styrene monomer represented by the following formula.

(Wherein P ¹ is a protecting group P which can be dissociated with a hydrogen atom or an acid and converted into an OH group)
As the copolymer containing the structural unit derived from maleic acid monomer, maleic _{anhydride, HOOCCH 2 = CH 2 COOH,} ROOCCH 2 = CH 2 COOH, ROOCCH 2 = CH 2 COOR ( wherein, R is a heteroatom And those having a structural unit derived from a maleic acid monomer represented by a hydrocarbon group having 1 to 22 carbon atoms which may contain

Examples of the copolymer containing a structural unit derived from a vinyl ether monomer include those represented by CH ₂ = CHOR. For example, R is linear or branched such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, etc. An alkyl group or a derivative thereof can be exemplified.

R is a group derived from a cycloalkane derived from an organic group having 4 to 20 carbon atoms having an alicyclic structure, such as cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, etc .; adamantane, bicyclo [ 2.2.1] heptane, tetracyclo [6.2.1.1 ^3,6 . And groups derived from bridged hydrocarbons such as 0 ^2,7 ] dodecane and tricyclo [5.2.1.0 ^2,6 ] decane.

  Examples of the functional group substituted with R include a hydroxyl group, a carboxyl group, a nitro group, a cyano group, and an amino group.

  Of these functional groups, a hydroxyl group, a carboxyl group, a cyano group and the like are preferable.

Examples of the copolymer containing a structural unit derived from an allylic monomer include allyl ether monomers and allyl ester monomers, and particularly CH ₂ ═CHCH ₂ C (CF ₃ ) ₂ OR, CH ₂ = CHCH ₂ (CH ₂ ) _n OR, CH ₂ = CHCH ₂ (CH ₂ ) _n COOR, CH ₂ = CHCH ₂ O (CH ₂ ) _n COOR (wherein R may contain a hetero atom) And those having a structural unit derived from an allylic monomer represented by a hydrocarbon group of 1 to 22 and n is an integer of 0 to 8.

As the copolymer containing a structural unit derived from a fluorine-containing ethylenic monomer, CF ₂ = CF ₂ , CF ₂ = CFCl, CH ₂ = CF ₂ , CFH = CH ₂ , CFH = CF ₂ , CF ₂ = CFCF ₃ , CH ₂ = CFCF ₃ , CH ₂ = CHCF _{3 and the} like.

Of these, tetrafluoroethylene (CF ₂ ═CF ₂ ) and chlorotrifluoroethylene (CF ₂ ═CFCl) are preferable because they have good copolymerizability and a high effect of imparting transparency.

  As the photoacid generator (b) used in the resist composition of the present invention, those similar to the photoacid generator (b) described in WO 01/74916 can be preferably exemplified, and the present invention also provides Can be used effectively.

  Specifically, it is a compound that generates an acid or a cation by irradiating light, for example, an organic halogen compound, a sulfonate ester, an onium salt (especially when the central element is iodine, sulfur, selenium, tellurium, nitrogen or phosphorus). A certain fluoroalkylonium salt), a diazonium salt, a disulfone compound, a sulfonediazide, and the like, or a mixture thereof.

  More preferable specific examples are as follows.

(1) TPS system:

Wherein X ⁻ is PF ₆ ⁻ , SbF ₆ ⁻ , CF ₃ SO ₃ ⁻ , C ₄ F ₉ SO ₃ ^{— and the} like; Rb ¹ , Rb ² , Rb ³ are the same or different, and CH ₃ O, H, t-Bu, CH _3, OH, etc.)

(2) DPI system:

(In the formula, X ⁻ represents CF ₃ SO ₃ ⁻ , C ₄ F ₉ SO ₃ ⁻ , CH ₃ —φ—SO ₃ ⁻ , SbF ₆ ⁻ ,

Rb ⁴ and Rb ⁵ are the same or different and H, OH, CH ₃ , CH ₃ O, t-Bu, etc.)

(3) Sulfonate type:

(Where Rb ⁶ is

Such)

  The content of the photoacid generator (b) in the resist composition of the present invention is preferably 0.1 to 30 parts by weight, more preferably 0.2 to 100 parts by weight of the acid dissociable functional group-containing polymer (a). -20 parts by weight is preferred, most preferably 0.5-10 parts by weight.

  When the content of the photoacid generator (b) is less than 0.1 parts by weight, the sensitivity is lowered, and when it is used in an amount of more than 30 parts by weight, the amount of the photoacid generator that absorbs light increases, and the light is sufficient to reach the substrate. The resolution will be reduced.

  Moreover, you may add to the resist composition of this invention the organic base which can act as a base with respect to the acid produced from said photo-acid generator (b). The organic base is preferably exemplified by those similar to those described in the pamphlet of International Publication No. WO01 / 74916, and can be used effectively in the present invention.

  Specifically, it is an organic amine compound selected from nitrogen-containing compounds, such as pyridine compounds, pyrimidine compounds, amines substituted with a hydroxyalkyl group having 1 to 4 carbon atoms, aminophenols, and the like. Hydroxyl group-containing amines are particularly preferable.

  Specific examples include butylamine, dibutylamine, tributylamine, triethylamine, tripropylamine, triamylamine, pyridine and the like.

  The content of the organic base in the photoresist composition of the present invention is preferably from 0.1 to 100 mol%, more preferably from 1 to 50 mol%, based on the content of the photoacid generator (b). When the amount is less than 0.1 mol%, the resolution tends to be low, and when the amount is more than 100 mol%, the sensitivity tends to be low.

  In addition, additives described in the pamphlet of International Publication No. WO01 / 74916, for example, sensitizers, dyes, adhesion improvers, water retention agents and the like are conventionally used in the resist composition of the present invention as necessary. Various additives can also be contained.

  Further, in the resist composition of the present invention, the same solvents as those described in the pamphlet of International Publication No. WO01 / 74916 can be preferably exemplified, and can be used effectively in the present invention.

Specifically, cellosolve solvents, ester solvents, propylene glycol solvents, ketone solvents, aromatic hydrocarbon solvents, or a mixed solvent thereof are preferable. Further, in order to enhance the solubility of the acid dissociable functional group-containing polymer (a), a fluorine-containing hydrocarbon solvent such as CH ₃ CCl ₂ F (HCFC-141b) or a fluorine solvent such as fluorine alcohol is used in combination. Also good.

  The amount of these solvents is selected depending on the type of solid content to be dissolved, the base material to be applied, the target film thickness, and the like. From the viewpoint of ease of application, the total solid content concentration of the resist composition is 0. It is preferably used in an amount of 5 to 70% by weight, preferably 1 to 50% by weight.

  Next, steps (II) to (IV) in the fine pattern forming method of the present invention performed using the resist composition of the present invention thus manufactured will be described with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing the fine pattern forming method of the present invention.

(II) Step of forming resist film First, as shown in FIG. 1A, a photosensitive composition using a fluororesin is applied to the substrate 11 by 0.01 to 5 μm, preferably 0.05 to 0 by spin coating. The film is applied in a thickness of 0.5 μm, more preferably 0.1 to 0.3 μm.

  Next, a pre-bake treatment is performed at a predetermined temperature of 150 ° C. or lower, preferably 80 to 130 ° C., to form a resin layer (photosensitive composition layer), that is, a resist layer 12.

  As the substrate used here, for example, a silicon wafer, a glass substrate, a silicon wafer or glass substrate provided with an organic or inorganic antireflection film, various insulating films, electrodes, wirings, etc. are formed on the surface. Silicon wafers with different steps, mask blanks, III-V group compound semiconductor wafers such as GaAs and AlGaAs, II-VI group compound semiconductor wafers, and piezoelectric wafers such as crystal, quartz or lithium tantalate, etc. It is not limited to.

The film coated with the resist composition used in the present invention preferably has a high transparency in the vacuum ultraviolet region, and specifically has an absorption coefficient of 193 nm wavelength of 1.5 μm ⁻¹ or less. It is preferably 0 μm ⁻¹ or less, particularly preferably 0.7 μm ⁻¹ or less, and further preferably 0.5 μm ⁻¹ or less. This coating can be effectively used in a lithography process using ArF laser (193 nm) light.

(III) Exposure Step Next, as shown in FIG. 1B, the resist layer 12 is irradiated with energy rays such as ArF excimer laser light as shown by an arrow 15 through a mask 13 having a desired pattern. Thus, pattern drawing is performed by selectively exposing a specific area 14.

  At this time, generally, energy rays (or chemical radiation), that is, X-rays, high-energy electron beams, synchrotron radiation, high-pressure mercury lamp characteristic lines, excimer laser light other than ArF excimer laser light, etc. are used as exposure light. Although it is possible to directly pattern-expose the resist film by scanning an electron beam, an ion beam line or the like without using a mask, the effect of the present invention is most exhibited when ArF laser light is used as an exposure light source. Is done.

  Subsequently, by performing post-exposure baking at 70 to 160 ° C., preferably 90 to 140 ° C. for 30 seconds to 10 minutes, as shown in FIG. 1C, a latent image is formed in the exposed region 14 of the resist film. 16 is formed. At this time, the acid generated by the exposure acts as a catalyst and the dissolution inhibiting group (protecting group) is decomposed, so that the solubility of the developer is increased and the exposed portion of the resist film is solubilized in the developer.

(IV) Development Step Next, when the resist film 12 subjected to post-exposure baking is developed with a developer, the unexposed portion of the resist film 12 remains on the substrate because the solubility in the developer is low. On the other hand, as described above, the exposed portion 14 is dissolved in the developer.

  As the developer, a 2.38 wt% tetramethylammonium hydroxide aqueous solution is preferably used. Furthermore, in order to adjust the paintability with the resist film, a 2.38 wt% tetramethylammonium hydroxide aqueous solution to which a surfactant or an alcohol such as methanol, ethanol, propanol or butanol is added is used. Also good.

  Next, after the developer is washed away with pure water, lower alcohol, or a mixture thereof, and the substrate is dried, a desired resist pattern 17 as shown in FIG. 1D can be formed.

Moreover, although the case where ArF laser light was used as the energy beam used here was described, F ₂ excimer laser beam (wavelength 157 nm) is also suitable as the energy beam used in the fine pattern forming method of the present invention.

  Further, KrF excimer laser light is also suitable as an energy beam used in the fine pattern forming method of the present invention.

  Moreover, a high energy electron beam is also suitable as an energy beam used for the fine pattern forming method of the present invention.

  A high energy ion beam is also suitable as an energy beam used in the fine pattern forming method of the present invention.

  X-rays generated from synchrotron radiation or the like are also suitable as energy rays used in the fine pattern forming method of the present invention.

  In the above example, the case where the resist film is formed on the substrate 11 has been described. However, this is not limited to a so-called substrate, and may be formed on a predetermined layer such as a conductive film or an insulating film on the substrate. In addition, an antireflection film such as DUV-30, DUV-32, DUV-42, and DUV-44 manufactured by Brewer Science can be applied on such a substrate, and the substrate is treated with an adhesion improver. As described above, the photosensitive composition and the substrate are not limited to the semiconductor substrate but include any substrate for manufacturing an electronic device.

  Further, by using the fine resist pattern formed in this way as a mask, a predetermined layer underneath is etched to form a desired fine pattern of a conductive film or an insulating film, and another process is repeated to form an electronic device such as a semiconductor device. Can be manufactured. Since these steps are well known, description thereof will be omitted.

  Next, the present invention will be described based on synthesis examples and examples, but the present invention is not limited to these examples.

Synthesis Example 1 (Synthesis of homopolymer of OH group-containing norbornene derivative (NB-1))
To a three-necked flask with an internal volume of 100 ml, under a nitrogen atmosphere, 15 ml of tetrahydrofuran, an OH group-containing norbornene derivative (NB-1):

After charging 2.3 g, 2 ml of a palladium catalyst solution prepared by the following method was added and polymerized at 30 ° C. for 6 hours. Thereafter, the reaction solution was filtered through celite, and then the filtrate was concentrated with an evaporator. After concentration, the solid content was dissolved again in 10 ml of HCFC-141b and reprecipitated in hexane to separate the polymer. Vacuum drying was performed until a constant weight was obtained, to obtain 0.8 g of a polymer.

  The weight average molecular weight of the polymer obtained by GPC analysis was 6500.

(Catalyst preparation method)
To a solution of 27 mg of π-allyl palladium chloride dimer in 1 ml of tetrahydrofuran was added a solution of 40 mg of silver hexafluoroantimonate in 1 ml of tetrahydrofuran, and the mixture was stirred for 1 hour at room temperature. A tetrahydrofuran solution of the complex catalyst was obtained.

In addition, the apparatus and measurement conditions used for physical property evaluation are as follows.
(1) NMR: manufactured by BRUKER
¹ H-NMR measurement conditions: 300 MHz (tetramethylsilane = 0 ppm)
¹⁹ F-NMR measurement conditions: 282 MHz (trichlorofluoromethane = 0 ppm)
(2) The weight average molecular weight was determined by gel permeation chromatography (GPC) using GPC HLC-8020 manufactured by Tosoh Corporation, one column manufactured by Shodex (one GPC KF-801 and one GPC KF-802). And two GPC KF-806Ms connected in series) and tetrahydrofuran (THF) as a solvent was flowed at a flow rate of 1 ml / min.

Synthesis Example 2 (Synthesis of homopolymer of OH group-containing norbornene derivative (NB-2))
Instead of the OH group-containing fluorine-containing norbornene derivative (NB-1) in Synthesis Example 1, the OH group-containing fluorine-containing norbornene derivative (NB-2):

The same operation as in Synthesis Example 1 was performed except that 2.2 g of was used, and 0.9 g of a copolymer was obtained.

The weight average molecular weight of this copolymer was 7000 from GPC analysis.
Synthesis Example 3 (Synthesis of copolymer of TFE and OH group-containing norbornene derivative (NB-1))
A 3-liter autoclave equipped with a valve, pressure gauge, stirrer and thermometer was replaced with nitrogen several times and then evacuated to obtain 266 g of OH group-containing fluorine-containing norbornene derivative (NB-1) and 1500 g of HCFC-141b. Prepared. Next, 350 g of tetrafluoroethylene (TFE) gas was charged from a valve, and 96 g of a 10.0 wt% perfluorohexane solution of heptafluorobutanoyl peroxide: (CF ₃ CF ₂ CF ₂ COO) ₂ was charged and reacted while stirring. The internal temperature was kept at 35 ° C.

As the reaction progresses, the internal pressure decreases and TFE is added to 0.9 MPaG (0.9 MPaG (9.2 kgf / cm ² G) from 0.9 MPaG (9.2 kgf / cm ² G) before the reaction. The pressure was raised to 9.2 kgf / cm ² G), the pressure was lowered by the reaction, and the pressure was raised by adding TFE, and the polymerization reaction was carried out for 30 hours.

During the polymerization, 48 g of a 10.0 wt% perfluorohexane solution of heptafluorobutanoyl peroxide: (CF ₃ CF ₂ CF ₂ COO) ₂ was added 5 times in total at an interval of 6 hours from the start.

  After the completion of the reaction, unreacted monomers were released, the polymerization solution was taken out, concentrated and then reprecipitated with hexane to separate the copolymer. Vacuum drying was performed until a constant weight was obtained, to obtain 150 g of a copolymer.

From the results of ¹ H-NMR and ¹⁹ F-NMR analysis, the composition ratio of this copolymer was a copolymer of 50/50 mol% of TFE / the OH group-containing norbornene derivative (NB-1).

The weight average molecular weight was 4500 by GPC analysis.
Synthesis Example 4 (Synthesis of copolymer of TFE and OH group-containing norbornene derivative (NB-2))
The same operation as in Synthesis Example 3 was performed except that 262 g of the OH group-containing fluorine-containing norbornene derivative (NB-2) was used in place of the OH group-containing fluorine-containing norbornene derivative (NB-1) in Synthesis Example 3, 140 g of coalescence was obtained.

From the results of ¹ H-NMR and ¹⁹ F-NMR analysis, the composition ratio of this copolymer was a copolymer of 50/50 mol% of TFE / the OH group-containing norbornene derivative (NB-2).

  The weight average molecular weight was 5000 by GPC analysis.

Examples 1 to 5 (Measurement of solubility in developer)
Using the fluoropolymer mixture in which the fluoropolymers obtained in Synthesis Examples 1, 3, and 4 were blended in the ratios shown in Table 1, the developer was developed by the quartz oscillator method (QCM method) as follows. The dissolution rate was measured.

(1) Preparation of sample: A solution (polymer concentration: 1 to 10% by weight) obtained by dissolving the above fluoropolymer mixture in PGMEA was applied to a quartz resonator plate with a diameter of 24 mm covered with gold at 110 ° C. After drying for 90 seconds, a 100 nm film was prepared.

(2) Measurement of dissolution rate: The film thickness is calculated from the vibration frequency of the crystal plate and measured.

  From the time when the quartz vibrator plate coated with the above-mentioned fluoropolymer was immersed in tetramethylammonium hydroxide (TMAH) aqueous solution of 2.38% by weight and 0.595% by weight which is a standard developer. The film thickness change with time was measured by the change in vibration frequency, and the dissolution rate per unit time (nm / sec) was calculated (reference: Advances in Resist Technology and Proceedings of SPIE Vol. 4690, 904 (2002). )). The results are shown in Table 1.

Comparative Examples 1 and 2 (Measurement of solubility in developer)
In the same manner as in Example 1, the developer dissolution rate of the fluoropolymer mixture obtained by blending the fluoropolymers obtained in Synthesis Examples 2, 3, and 4 at the ratio shown in Table 1 was measured. The results are shown in Table 1.

Reference Examples 1 to 4 (Measurement of solubility in developer)
The developer dissolution rate of the fluoropolymers obtained in Synthesis Examples 1 to 4 was measured in the same manner as in Example 1. The results are shown in Table 1.

It is sectional drawing which shows the fine pattern formation method of this invention along a process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Substrate 12 Resist layer 13 Mask 14 Exposure area 15 Exposure light 16 Latent image 17 Resist pattern

Claims (10)

(I) (a) an acid-dissociable functional group-containing polymer,
A step of producing a resist composition comprising (b) a photoacid generator and (c) a dissolution inhibitor;
(II) a step of forming a resist film made of the resist composition on the substrate or a predetermined layer on the substrate;
(III) a step of selectively irradiating a predetermined region of the resist film with an energy ray for exposure; and (IV) developing the resist film after the exposure to selectively expose an exposed portion of the resist film. A fine pattern forming method comprising a step of removing and forming a fine pattern, wherein the dissolution inhibitor (c) is represented by the formula (M-1):-(M1)-(M2)-(N1)-(M -1)
[Where:
M1 is a structural unit derived from a norbornene derivative, and in M1, formula (1):

(Wherein Rf ¹ and Rf ² are the same or different and may contain an ether bond, a C 1-10 fluorine-containing alkyl group; X is F or CF ₃ ; Y ¹ is an OH group and / or an acid; A structural unit derived from at least one monomer (m1) selected from fluorine-containing norbornene derivatives having a site represented by an acid-dissociable functional group that dissociates and changes to an OH group;
M2 is a structural unit derived from at least one monomer (m2) selected from a fluorine-containing norbornene derivative having an acid-dissociable functional group Y ² that is dissociated by a —COOH group and / or an acid to change to a —COOH group;
N1 is a structural unit derived from the monomer (n1) copolymerizable with the monomer (m1) and / or the monomer (m2).
The structural unit M1 is 55 to 100 mol%, the structural unit M2 is 0 to 45 mol%, the structural unit N1 is 0 to 20 mol%, and M1 + M2 is 80 to 100 mol% And a polymer (A) having a molar ratio of M1 / M2 of 55/45 to 100/0 is used. The fine pattern formation according to claim 1, wherein the acid-dissociable functional group-containing polymer (a) is a polymer having an alicyclic hydrocarbon structure, and has an absorption coefficient of light of 193 nm wavelength of 1.5 µm ^-1 or less. Method. In the dissolution inhibitor (c), the structural unit M1 is represented by the formula (2):

(Wherein X ¹ and X ² are the same or different and H, F or CF ₃ ; X and Y ¹ are the same as those in formula (1)), and at least one selected from structural units derived from norbornene derivatives The fine pattern forming method according to claim 1, wherein the structural unit is a structural unit of In the dissolution inhibitor (c), the structural unit M2 is represented by the formula (3):

Wherein X ³ , X ⁴ and X ⁵ are the same or different, H, F or CF ₃ ; R ¹ is a divalent organic group having 1 to 20 carbon atoms; n1 is 0 or 1; Y ² is a formula The fine pattern forming method according to any one of claims 1 to 3, which is at least one structural unit selected from structural units derived from norbornene derivatives represented by (M-1). In the resist composition, when the total weight of the acid dissociable functional group-containing polymer (a) and the dissolution inhibitor (c) is 100, the abundance ratio of the polymer (a) and the dissolution inhibitor (c) (a) / (C) is 30 / 70-99 / 1 weight ratio, The fine pattern formation method in any one of Claims 1-4. (A) an acid-dissociable functional group-containing polymer,
(B) a photoacid generator and (c) a dissolution inhibitor, wherein the dissolution inhibitor (c) is represented by the formula (M-1):
-(M1)-(M2)-(N1)-(M-1)
[Where:
M1 is a structural unit derived from a norbornene derivative, and in M1, formula (1):

(Wherein Rf ¹ and Rf ² are the same or different and may contain an ether bond, a C 1-10 fluorine-containing alkyl group; X is F or CF ₃ ; Y ¹ is an OH group and / or an acid; A structural unit derived from at least one monomer (m1) selected from fluorine-containing norbornene derivatives having a site represented by an acid-dissociable functional group that dissociates and changes to an OH group;
M2 is a structural unit derived from at least one monomer (m2) selected from a fluorine-containing norbornene derivative having an acid-dissociable functional group Y ² that is dissociated by a —COOH group and / or an acid to change to a —COOH group;
N1 is a structural unit derived from the monomer (n1) copolymerizable with the monomer (m1) and / or the monomer (m2).
The structural unit M1 is 55 to 100 mol%, the structural unit M2 is 0 to 45 mol%, the structural unit N1 is 0 to 20 mol%, and M1 + M2 is 80 to 100 mol% A resist composition for forming a fine pattern, which is a polymer having a M1 / M2 molar ratio of 55/45 to 100/0. The resist composition according to claim 6, wherein the acid-dissociable functional group-containing polymer (a) is a polymer having an alicyclic hydrocarbon structure, and an absorption coefficient of light having a wavelength of 193 nm is 1.5 μm ⁻¹ or less. . In the dissolution inhibitor (c), the structural unit M1 is represented by the formula (2):

(Wherein X ¹ and X ² are the same or different and H, F or CF ₃ ; X and Y ¹ are the same as those in formula (1)), and at least one selected from structural units derived from norbornene derivatives The resist composition according to claim 6, which is a structural unit of In the dissolution inhibitor (c), the structural unit M2 is represented by the formula (3):

Wherein X ³ , X ⁴ and X ⁵ are the same or different, H, F or CF ₃ ; R ¹ is a divalent organic group having 1 to 20 carbon atoms; n1 is 0 or 1; Y ² is a formula The resist composition according to claim 6, which is at least one structural unit selected from structural units derived from norbornene derivatives represented by (M-1). When the total weight of the acid dissociable functional group-containing polymer (a) and the dissolution inhibitor (c) is 100, the abundance ratio (a) / (c) of the polymer (a) and the dissolution inhibitor (c) is 30. The resist composition according to claim 6, which has a weight ratio of / 70 to 99/1.

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