WO2004024787A1 - Process for production of fluoropolymers for resist - Google Patents

Abstract

A process for the production of fluoropolymers for resist which are excellent in transparency in the vacuum ultraviolet region and useful as photoresists (particularly F2 resist) capable of forming ultrafine patterns and which each comprise repeating units (M1) resulting from a fluorinated ethylenic monomer (m1) having two or three carbon atoms and at least one fluorine atom and/or repeating units (M2) resulting from an optionally fluorinated monomer (m2) capable of giving an alicyclic structure to the backbone chain of the polymer and have in the polymer acid-reactive groups (Y1) or groups (Y2) convertible into acid-reactive groups (Y1), characterized in that the monomer (m1) and/or the monomer (m2) is radical-polymerized by the use of a fluorine-containing polymerization initiator.

Description

 Akira Itoda Manufacturing method of fluoropolymer for resist

 The present invention relates to a method for producing a fluorine-containing polymer for a resist which is transparent in a vacuum ultraviolet region, in particular, F 2 laser (157 nm) light. Background art

 As the need for high integration of large-scale integrated circuits (LSI) increases, photolithography technology requires microfabrication technology. In response to this requirement, far ultraviolet light with a shorter wavelength than conventional g-rays (wavelength 436 nm) and 〖-rays (wavelength 365 nm), and a single KrF excimer laser (wavelength 248 nm) Attempts have been made to use one light of ArF excimer laser (wavelength: 193 nm) as an exposure light source, and it is being put to practical use.

 Recently, a process using F 2 laser light (wavelength: 157 nm) in the vacuum ultraviolet region is being studied as a further ultra-fine processing technology, and as an exposure technology aiming at 0.07 m of technology one node in the future. Promising. Examples of such conventional resist resins used in photolithography include those in which some or all of the hydroxyl groups of a phenolic resin are protected with a protecting group such as acetal or ketal (KrF resist), methacrylic Examples include those in which an acid-dissociable ester group has been introduced into the hydroxyl group of an acid-based resin (ArF resist). '

However, these conventional resist polymers have strong absorption in the vacuum ultraviolet wavelength range, and are transparent to a single F2 laser at a wavelength of 157 nm, which is being considered for use as a process for ultra-fine patterning. Is low. (The number is large). Therefore, in order to expose with an F2 laser, the thickness of the resist must be extremely thin, and it is practically difficult to use it as a single-layer F2 resist.

 Therefore, a resist using a fluoropolymer having high transparency to one light of F2 laser is being studied.

 Among them, fluoropolymers obtained by copolymerizing fluoroolefins having 2 or 3 carbon atoms represented by tetrafluoroethylene and the like, and fluoropolymers having a ring structure in the main chain or the main chain have transparency and It is preferable from both aspects of dry etching resistance, and is useful as a resist polymer.

 As these fluorine-based resists, a fluorinated polymer for a resist having a functional group that reacts with an acid, and a resist composition using the same have been proposed.

(See, for example, International Publication No. WO 00/17772 Pamphlet, International Publication WO 0/67072 Pamphlet, International Publication WO 01/74916 Pamphlet).

 In these patent documents, copolymers of fluoroolefins represented by tetrafluoroethylene and alicyclic monomers represented by norpolene (or norbornene derivative) are specifically described. The method involves radical polymerization of fluororefin and an alicyclic monomer with a polymerization initiator such as a hydrocarbon-based peroxide.

 However, the fluoropolymers obtained by these production methods were insufficient in transparency in the vacuum ultraviolet region.

The present inventors have conducted intensive studies in view of these problems, and have conducted radical (co) polymerization of fluorinated olefins and monomers that form a ring structure in the main chain, including those for resists having an acid-reactive group. When a fluoropolymer is obtained, radical (co) polymerization is performed using a specific radical polymerization initiator, so that a fluoropolymer for resist can be efficiently obtained, and the fluoropolymer is transparent to F 2 laser light. sex Was found to improve dramatically.

 A first object of the present invention is to provide an F 2 laser beam by radically (co) polymerizing a monomer that forms a ring structure in a fluoroolefin or a main chain using a specific radical polymerization initiator. An object of the present invention is to provide a method for producing a fluoropolymer for resist having excellent transparency in the above.

 A second object of the present invention is to provide a composition for a resist, particularly an F2 resist, containing a fluoropolymer having excellent transparency in vacuum ultraviolet light obtained by such a production method.

A third object of the present invention is to provide a novel polymer comprising tetrafluoroethylene and a norpolenene derivative, which is excellent in transparency and has a CF ₃ group introduced into the polymer terminal at a high ratio. Disclosure of the invention

The first aspect of the present invention is that a repeating unit (Ml) derived from a fluorine-containing ethylenic monomer (ml) having 2 or 3 carbon atoms and having at least one fluorine atom, and And / or has a repeating unit (M 2) derived from a monomer (m 2) which may contain a fluorine atom capable of giving an aliphatic ring structure to the polymer main chain, and the polymer contains an acid. the reaction is acid-reactive group Y ¹ or an acid-reactive group Y ¹ can be converted into groups (hereinafter referred to as "acid-reactive group conversion group") in obtaining the fluorine-containing polymer having a Y ^2, fluorine-containing ethylenic Vacuum ultraviolet, characterized by radically polymerizing a monomer (ml) and Z or a monomer (m 2) capable of giving an aliphatic ring structure to the polymer main chain using a polymerization initiator having a fluorine atom. The present invention relates to a method for producing a fluoropolymer for resist having excellent light transparency.

According to the production method of the present invention, not only can the polymerization reaction proceed promptly to increase the molecular weight, but also the resulting fluoropolymer can be treated with light in the vacuum ultraviolet region. Excellent transparency to lines.

The second aspect of the present invention is (A-1) an acid dissociable functional group that can be converted to a 〇H group by an acid, a COOH group, or an acid that can be dissociated into a COOH group by an acid. containing fluorine polymer having an acid-reactive group Y ¹ of at least one sexual functional groups,

 (B) a photoacid generator, and

 (C) Solvent

A fluororesin composition, wherein the fluoropolymer (A-1) is a polymer obtained by the production method according to the first aspect of the present invention. Such a photoresist composition provides a resist film having excellent vacuum ultraviolet light transparency, and is particularly useful when used in an ultrafine processing process.

The third aspect of the present invention comprises, as essential components, a repeating unit (M1A) derived from tetrafluoroethylene and a repeating unit (M2A) derived from a norbornene derivative (m2a) which may contain a fluorine atom. A polymer containing at least one CF ₃ group at one end of the polymer main chain, and being detected by ¹⁹ F-NMR analysis. Assuming that the intensity of one CF ₃ signal at the end of the main chain is H (terminal CF ₃ ) and the intensity of the main chain—CF ₂ —signal is H (—CF ₂ —), equation (1):

0.3 ≥H (terminal CF ₃ ) / H (—CF ₂ —) ≥0.01 The present invention relates to a fluoropolymer satisfying the relational expression (1).

Such a fluoropolymer can more effectively improve transparency, is useful as the above-mentioned resist, and is a polymer useful not only for the resist but also for other optical uses. BEST MODE FOR CARRYING OUT THE INVENTION

The fluorine-containing polymer produced by the production method of the present invention includes a repeating unit (Ml) derived from a fluorinated ethylene monomer (ml) and a fluorine atom capable of giving an aliphatic ring structure to the polymer main chain. Which contains one or both of the repeating units (M2) derived from the monomer (m 2) which may contain the acid-reactive group Y ¹ or the acid-reactive group converting group Y ² (Hereinafter, also referred to as “acid-reactive functional group Y”). Further, it may further include an optional repeating unit (さ ら に).

 The fluorine atom in the fluoropolymer obtained in the present invention is not always derived from the monomer (m1) or the monomer (m2), but may be derived from any other comonomer. It may be derived.

 The method for introducing the acid-reactive functional group Y into the polymer will be described in detail later.

 (I) a method of copolymerizing a monomer having an acid-reactive functional group Y as a monomer (ml) and / or a monomer (m2),

 (II) A method of copolymerizing a monomer (n 1) other than the monomers (ml) and (m2) and having an acid-reactive functional group Y

And so on.

 Hereinafter, first, the fluorine-containing radical polymerization initiator will be described, and then each monomer to be subjected to radical polymerization will be specifically described. 'The production method of the present invention is characterized in that, when the above-mentioned fluoropolymer having the acid-reactive functional group Y is obtained, radical polymerization is carried out using a polymerization initiator containing a fluorine atom.

By using a fluorine-containing polymerization initiator, the radical polymerization reactivity of the fluorine-based monomer is improved, and the initiator residue at the terminal of the polymer also becomes a fluorine-containing terminal, and transparency in the vacuum ultraviolet region is obtained. Is further improved. The polymerization initiator having a fluorine atom can be used as long as it is a compound that generates a radical by temperature (eg, heat) or light. Among them, a fluorine-containing organic peroxide is preferred.

 As the fluorinated organic peroxide, one or more selected from fluorinated dihydroxy peroxides, fluorinated veroxydicarboxylic acids, fluorinated peroxide esters, and fluorinated dialkyl peroxides are preferable. .

 Among them, fluorinated disilvoxides are preferred because they can promote radical polymerization reactivity and can further improve the transparency of the obtained polymer in the vacuum ultraviolet region.

 These fluorine-containing organic peroxides are obtained by substituting part or all of the hydrogen atoms of a hydrocarbon group such as an alkyl group or an aryl group in a fluorine-free hydrogen-based peroxide skeleton with a fluorine atom. It was done. For example, a peroxide having a fluorinated alkyl group, a fluorinated aryl group, a fluorinated alkyl group having an ether bond, or a fluorinated alkyl group substituted with a fluorinated aryl group (that is, a fluorinated aralkyl group) in the skeleton. Things. Among them, an organic peroxide having a fluorinated alkyl group or a fluorinated alkyl group having an ether bond is preferred from the viewpoint of improving the transparency. Fluorinated alkyl group The fluorinated alkyl group having a polyester bond may be linear or branched.

 The fluorinated alkyl group or the fluorinated alkyl group having an ether bond is a perfluoroalkyl group or a substituted perfluoroalkyl group in which a part of a fluorine atom is substituted with a halogen atom such as a hydrogen atom, a chlorine atom, or a bromine atom. Alkyl groups are preferred because they are particularly excellent in the effect of improving transparency.

As the fluorine-containing disil peroxides, a compound represented by the formula: O o

R f ³ -C-O— O-C-R f ⁴

(In the formula, R f ³ and R f ⁴ are the same or different and each may have an ether bond, a fluorinated alkyl group having 1 to 40 carbon atoms, a fluorinated aryl group having 6 to 40 carbon atoms or a carbon number. And a fluorinated aralkyl group of 7 to 40).

 O 〇

X- CF-O- O- C-tCF ₂ ~ X '

 (Wherein m and n are the same or different and are integers from 1 to 20; X and X 'are the same or different and F (C1 or H)) is preferred.

 In particular,

 〇

[H (CF ₂ CF ₂ ) _n CO] ₂ (where n is an integer of 1 to 5),

 〇

[C 1 (CF ₂ CF ₂ ) _n CO] ₂ (where n is an integer of 1 to 5)

0

 II

[CF ₃ CF ₂ (CF ₂ CF ₂ ) _n CH ₂ CO] ₂

 (Where n is 0 or an integer from 1 to 5)

 0

 II

[CF ₃ (CF ₂ CF ₂ ) _n CH ₂ CO] ₂

 (Where n is 0 or an integer from 1 to 5)

 0

 II

[(CF ₃ ) ₂ CHC〇] ₂ , 〇

 II

[(CF ₃ ) ₃ CCO] ₂ ,

CF ₃ CF ₃ 〇

 I I II

[C ₃ F ₇ 0 (CFCF ₂ 〇) _n CF—CO] ₂

 (Where n is 0 or an integer from:! To 5),

 O

II

[C ₃ F ₇ 0 (CF ₂ CF ₂ CF ₂ 0) _n CF ₂ CF ₂ C〇] ₂

 (Where n is 0 or an integer of 1 to 5),

O

II

[CF ₃ 〇CF ₂ CF ₂ CO] 2,

 O

II

[CF ₃ CF ₂ CO] ₂

 〇

 II

[CF ₃ CF ₂ CF ₂ CO] ₂

And the like are preferably exemplified.

 Each monomer that undergoes radical polymerization using such a fluorine-containing polymerization initiator will be described.

 The monomer (ml) that gives the repeating unit (Ml) to the fluorinated polymer is a polymerizable, especially a radically polymerizable, fluorinated ethylene having 2 or 3 carbon atoms having one carbon-carbon double bond. It is a monomer having at least one fluorine atom.

 Such a fluorine-containing ethylenic monomer (ml) is a monoene compound having one polymerizable carbon-carbon double bond, and does not form a repeating unit having a ring structure in the main chain even by polymerization.

The fluorinated ethylenic monomer (ml) may or may not have an acid-reactive functional group Y in the monomer, but usually has an acid-reactive functional group. It is preferable to use a monomer which is not used, since the radical polymerization reactivity is good and the transparency can be more effectively improved.

 Preferred fluorine-containing ethylenic monomers (ml) include those in which at least one hydrogen atom of ethylene or propylene is substituted with a fluorine atom. Other hydrogen atoms may be substituted by halogen atoms other than fluorine atoms.

 Among them, a monomer in which a fluorine atom is bonded to at least one carbon atom constituting a carbon-carbon double bond is preferable. As a result, a fluorine atom can be introduced into the repeating unit (Ml), that is, into the polymer main chain, and a fluorine-containing polymer giving particularly excellent transparency in the vacuum ultraviolet region can be effectively obtained.

More specifically, at least one monomer selected from tetrafluoroethylene, chlorofluoroethylene, vinylidene fluoride, vinyl fluoride, trifluoroethylene, hexafluoropropylene, and CH ₂ = CFCF ₃ The body is preferred.

 Among them, at least one or a mixture of two or more of tetrafluoroethylene, chlorotrifluoroethylene, vinylidene fluoride or hexafluoropropylene is particularly preferable in terms of transparency. Fluoroethylene and / or chlorotrifluoroethylene are preferred. Next, a monomer (m 2) which may have a fluorine atom and which can give a repeating unit (M 2) having an aliphatic ring structure in the polymer main chain will be described.

When such a monomer (m 2) is used for a resist, a repeating unit (M 2) having an aliphatic ring structure which improves dry etching resistance can be introduced into the polymer main chain. When this effect is combined with the above-mentioned effect of improving the transparency in the vacuum ultraviolet region, the fluoropolymer having an aliphatic ring structure in the main chain obtained by the production method of the present invention can be used as a resist for F 2 laser. Is particularly preferred. The monomer (m2) may be one selected from unsaturated cyclic compounds having a radically polymerizable carbon-carbon unsaturated bond in a ring structure, or may be a main chain obtained by cyclopolymerization of a jelly conjugate. The compound may be selected from non-conjugated gen compounds that can form a ring structure.

 Further, the monomer (m2) may or may not have the acid-reactive functional group Y in the monomer.

 By (co) polymerizing this monomer (m2), a polymer having a monocyclic or multicyclic aliphatic ring structural unit in the main chain can be obtained. The first preferable monomer (m2) is a monocyclic monomer having a radically polymerizable carbon-carbon unsaturated bond in its ring structure and having no acid-reactive functional group Y.

(m2-1), and is preferably an aliphatic unsaturated hydrocarbon compound having a 3- to 8-membered ring structure which may contain an ether bond in the ring structure.

 Specifically, the monomer (m2-1)

And the like.

 Further, a monomer in which part or all of the hydrogen atoms of these monomers (m 2-1) are substituted with a fluorine atom may be used.

And the like.

 The second preferable monomer (m2) is a monomer (m2_2) having a monocyclic aliphatic unsaturated hydrocarbon compound having an acid-reactive functional group Y, and having an ether bond in the ring structure. It is preferably an unsaturated hydrocarbon compound having a 3- to 8-membered ring structure which may be contained. As described above, the monomer (m2-2) may be a monomer in which part or all of the hydrogen atoms have been substituted with fluorine atoms.

 The monocyclic monomer (m2-2) having an acid-reactive functional group Y is, specifically,

And the like.

The third preferred of the monomer (m2) is to provide a structural unit having an aliphatic bicyclic structure in the polymer main chain, and to have an aliphatic bicyclic structure having no force or acid-reactive functional group Y. It is a monomer (m 2-3). Preferred monomer (m2-3) is norbo It is a renene derivative.

 The monomer having an aliphatic bicyclic structure not having the acid-reactive functional group Y (m 2 13) is specifically,

And so on.

 The above-mentioned exemplified norponenes may be those obtained by introducing a fluorine atom into the ring structure. By introducing a fluorine atom, the transparency can be improved without lowering the dry etching resistance.

 Specifically, the formula:

(In the formula, A, B, D and D 'are the same or different, and all are H, F, an alkyl group having 1 to 10 carbon atoms or a fluorine-containing alkyl group having 1 to 10 carbon atoms.

M is an integer from 0 to 3; Provided that any one of A, B, D, and D contains a fluorine atom). 1605

 13

, FFF CFc, FF CF X

(n: l ~: 10,

 (X: H, F, CI)

Fluorine-containing norpolene represented by X or the like is obtained.

 others,

 (A, B, D, and D 'are H, F, an alkyl group having 1 to 10 carbon atoms or a fluorinated alkyl group).

 A preferred fourth of the monomer (m2) is a monomer having a structural unit having an aliphatic bicyclic structure in the polymer main chain and containing an aliphatic bicyclic structure having an acid-reactive functional group Y. Body (m2-4). The preferred monomer (m2-4) is a norpolene derivative.

The monomer (m2-4) containing an aliphatic bicyclic structure having an acid-reactive functional group Y is specifically, (m: integer from 0 to 3)

And so on.

 Further, a monomer (m 2-4) containing an aliphatic bicyclic structure having an acid-reactive functional group Y is obtained by substituting some or all of the hydrogen atoms bonded to the ring structure with fluorine atoms. This is preferable because it can impart further transparency to the polymer.

 In particular,

(In the formula, A, B and D are the same or different, and all may include H, F, an alkyl group having 1 to 10 carbon atoms or an ether bond having 1 to 10 carbon atoms. R is a divalent hydrocarbon group having 1 to 20 carbon atoms, a fluorinated alkylene group having 1 to 20 carbon atoms or a fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms; a Is an integer of 0 to 5; b is 0 or 1. However, when b is 0 or R does not contain a fluorine atom, any one of A, B and D has a fluorine atom or an ether bond. Fluorine containing A fluorine-containing norponene derivative represented by the following formula: Among these, it is preferable that any of A, B, and D is a fluorine atom, or when A, B, and D do not contain a fluorine atom, the fluorine content of R is 60% by weight. It is preferably the above, and more preferably a perfluoroalkylene group, from the viewpoint of imparting transparency to the polymer. In particular,

-Y

CF ₃ CF ₃

(n: 0 to; 10, X: F or CF ₃ )

F

Norpolene derivatives shown by ₍ e.g.,

 Furthermore,

(Wherein, Α, Β and D are the same or different, and all are H, F, an alkyl group having 1 to 10 carbon atoms or a fluorinated alkyl which may have an ether bond having 1 to 10 carbon atoms) R is a divalent hydrocarbon group having 1 to 20 carbon atoms, a fluorinated alkylene group having 1 to 20 carbon atoms or a fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms; An integer of from 5 to 5; b represents a fluorine-containing norportene derivative represented by 0 or 1).

 In particular,

CI 3 C ₃ Five

 17

CFO) _n CF ₂ CF-Y

CF, CF ₃ CF ₃

(CF ₂ CFO) _n CF ₂ CF-Y

 CFg CFg

Norpolene derivatives such as (n: 0 to: LO) are preferred.

 Furthermore, a monomer (m2-4) containing an aliphatic bicyclic structure having an acid-reactive functional group Y is preferably represented by the following formula:

(Wherein, unlike the R i ¹ R f ² same or a fluorine-containing alkyl group having fluorine-containing alkyl group or an ether bond of one to 10 carbon atoms; Unlike A, B, D are the same or different and each is H, F, C, a C 1-10 alkyl group or a fluorine-containing alkyl group optionally containing an ether bond having 1-10 carbon atoms; R is H or an alkyl group having 1-10 carbon atoms; 0-5 Fluorine-containing norponene derivative represented by the following formula <

(R and n are the same as above; X ⁴ = H, F or CI; m = l to: LO) And so on.

 More specifically,

(m = l~: LO) like are preferably mentioned _c

 Other, formula:

(Wherein, R f R f ² are the same or different and each is a fluorine-containing alkyl group having 1 to 10 carbon atoms or a fluorine-containing alkyl group having an ether bond; B and D are The same or different, each of which is H, F, C1, an alkyl group having 1 to 10 carbon atoms or a fluorinated alkyl group which may contain an ether bond having 1 to 10 carbon atoms; R is H or 1 carbon atom; To 10 alkyl groups; n is an integer of 0 to 5).

 These exemplified monomers (m2-3) and (m2-4) each having an aliphatic bicyclic structure are particularly preferable as a raw material for a resist polymer, since they can impart dry etch resistance to the polymer. Further, the production method of the present invention is also preferable in that a polymer can be efficiently produced by a radical polymerization method and transparency can be effectively improved.Lenorpartene derivatives containing a fluorine atom in a bicyclic structure are particularly preferable. It is preferable in terms of transparency, and is also preferable in that a polymer can be efficiently produced by a radical polymerization method and the transparency can be effectively improved by the production method of the present invention.

 In addition, a norpolenene derivative (m2-4) having an acid-reactive functional group Y is preferable because a functional group necessary for resist application can be efficiently introduced into a polymer, and as a result, transparency and dry etching resistance are advantageous. .

 A fifth preferred monomer (m2) is a non-conjugated diene compound (m2-5) which may have a fluorine atom and can form an aliphatic ring structure by polymerization. The non-conjugated diene compound (m2-5) can efficiently give a polymer having a repeating unit having a ring structure in the main chain, and can improve the transparency in the vacuum ultraviolet region as described above.

 As the non-conjugated diene compound (m2-5), for example, a specific divinyl compound which gives a monocyclic structure to the main chain by cyclopolymerization is preferable.

 As a specific example, for example, a formula which may have a fluorine atom or an acid-reactive functional group Y:

CH ₂ = CHCH ₂ -C-CH ₂ CH = CH ₂ YZ ¹

And CH ₂ = CHCH ₂ -C-CH ₂ CH = CH ₂

Z ¹ Z ²

(In the formula, Z ¹ and Z ² are the same or different, and are a hydrogen atom, a fluorine atom, a carbon number: a hydrocarbon group which may have an ether bond of 5 to 5, an ether bond of 1 to 5 carbon atoms, A fluorine-containing alkyl group which may have a).

 By subjecting the diaryl compound to radical cyclopolymerization,

CH

Yaichi CH

(Wherein, tau zeta ² are as defined above) to form a structural unit of a single annular in the main chain represented by.

Also in these cyclized radical polymerizations, a fluoropolymer having a cyclic structure can be efficiently obtained by using the above-mentioned fluoropolymerization initiator, and as described above, the transparency in the vacuum ultraviolet region can also be improved. It is. Here, the acid-reactive functional group γ will be described. As said gamma acid reactive functional group, a convertible acid reactive group conversion group gamma ² generic acid reactive groups gamma ¹ and the acid-reactive group gamma ^1.

Acid-reactive group gamma ¹ in the present invention refers to the acid-labile or acid-decomposable functional groups functional groups Contact and acid condensate compatibility. ①Acid dissociable or acid decomposable functional group:

 An acid-labile or acid-decomposable functional group is a functional group that is insoluble or hardly soluble in Al-rikari before reacting with an acid, but can be solubilized in Al-lili by the action of acid. . This change in solubility in alkali makes it usable as a base polymer for a positive resist.

Specifically, it has the ability to change into —OH groups, —COOH groups, —SO ₃ H groups, and the like by the action of acids or cations, and as a result, the fluoropolymer itself becomes soluble in alkali.

 The acid-dissociable or acid-decomposable functional group is, specifically,

R ⁷ R ¹⁰ R ¹³

OC-R ⁸ OCEUCOOC— R ¹ -OC-OR ¹⁴

R ⁹ RR

R ¹⁸ H Rishi l ■ CH. HoCH ri _:

OCOC-R ¹⁹ 0 O 〇 〇 〇

 II \

OR ²⁰ C,

 1 1 6

R ²¹ R ²² R ²³

R ²⁴ R ²⁷

COOC-R ²⁵ OS i— R ²⁸

 p 26 29

(Where R ⁷ R ⁸ R ⁹ R ¹⁰ R ¹¹ , R ¹² R ¹⁴ R ¹⁸ R ^{19 20} , R ²¹ R ²² R ²⁴ R ²⁵ R ²⁶ R ²⁷ R ²⁸ R ²⁹ are the same or different and have the same number of carbon atoms. 1 10 hydrocarbon groups; R ¹³ R ¹⁵ R ¹⁶ are the same or different; H or C 1 10 hydrocarbon groups; R ¹⁷ R ²³ are the same or different; C 2 10 divalent carbon Hydrogen group)

Can be preferably used, and more specifically, OCH ₂ 0 CH ₃ , -OCH ₂ OC ₂ H ₅ ,

-OC (CHg) 3 -OCH ₂ COOC (CH ₃ ) 3

-O

.

CH CHCH CHQCHCH

 / \ / \

oo -COOC (CH ₃ ) ₃ , -OS i (CH ₃ 3) 3

(R ³ ° is an alkyl group having 1 to 10 carbon atoms)

And the like are preferably exemplified.

(2) Functional group reactive with acid condensation:

 The acid-condensation-reactive functional group is soluble in an alkaline developer (or other developing solvent) before reacting with the acid, but the acid itself causes the polymer itself to be dissolved in an alkaline developer (or It is a functional group that can be made insoluble in other developing solvents.

 Specifically, a self-condensation, polycondensation by the action of an acid or a cation, or a functional group that causes a condensation reaction or a polycondensation reaction with a cross-linking agent by the action of an acid in the presence of a crosslinking agent, or a rearrangement reaction by an acid-cation (For example, pinacol rearrangement, carbinol rearrangement), etc., which cause a polarity change, and as a result, the polymer itself is insoluble in an alkaline developer (or other developing solvent). It becomes.

 By such insolubilization, it can be used as a base polymer for a negative resist.

Acid condensable functional groups include —〇H, one C〇OH, one CN, -SO3H, Those selected from epoxy groups and the like are preferred specific examples.

 When used, the crosslinking agent is not particularly limited, and may be arbitrarily selected from those conventionally used as a crosslinking agent for a negative resist. Preferred specific examples of the crosslinking agent include N-methylolated melamine, N-alkoxymethylated melamine compound, urea compound, epoxy compound and isocyanate compound.

More Among the acid-reactive group Y ^1, OH groups, acid labile functional group which can be converted to OH group with an acid, COOH groups, acid labile functional group that dissociates to can be changed to CO OH group with an acid At least one is preferred.

 Acid dissociable functional groups that can be converted to 0H groups with an acid include:

1〇C (R ³¹ ) ₃ , -OCHoOR ³² , _〇COC (R ³³ ) ₃ ,

 II

-OCHOR ³⁴ °

CH ₃ ,-

(Wherein, R ³¹ , R ³² , R ³³ and R ³⁴ are the same or different and each is an alkyl group having 1 to 5 carbon atoms).

 More specifically,

-OC (CH ₃ ) ₃ , one OCH ₂ OCH ₃ , — OCH ₂ OC ₂ H ₅ ,

-O

Can be preferably exemplified. Above all, in terms of good acid reactivity, 2003/011605

 twenty five

— OC (CH ₃ ) ₃ , — OCOC (CH ₃ ) ₃ , — OCH ₂ OCH ₃ ,

 O

One OCH ₂ OC ₂ H ₅ is preferable, and _〇C (CH ₃ ) ₃ , —OCH ₂ 〇CH ₃ , and one OCH ₂ OC ₂ H ₅ are more preferable in terms of good transparency.

 Acid dissociable functional groups that can be converted to one C〇〇H group with an acid include:

R ²⁵ R ²⁸ R ³¹

/ / I

-COOC-R ²⁶ one ^{_{OCH 2 COOC- R 29 - COC- OR}} 32

 \ \ II I

R ²⁷ R ³⁰ OR ³³ ,

R 34 R 36

 /

-COC-O-COCOC- R ³⁷

 II II II \

0 R ³⁵ OOR ³⁸

(Wherein, R ³⁵ , R ³⁶ , R ³⁷ , R ³⁸ , R ³⁹ , R ⁴ , R ⁴¹ , R ⁴² , R ⁴⁶ , R ⁴⁷ , R ⁴⁸ are the same or different, and each has 1 to 10 carbon atoms. R ⁴³ and R ⁴⁴ are the same or different, and each is H or a hydrocarbon group having 1 to 10 carbon atoms; 1 ⁴⁵ is a divalent hydrocarbon group having 2 to 10 carbon atoms). And more specifically

-COOC (CH ₃ ) ₃ , -OCH ₂ COOC (CH ₃ 3) 3

-

OO CH ₃ , O CH ₃ o

(R ³² is the same as the above formula) PC orchid painting 11605

26 and the like are preferred.

These acid-reactive group Y ¹ can usually be introduced monomer having an acid-reactive group Y ¹ to the polymer by accordance connexion polymerization to the preparation of the present invention.

Or monomers having an acid-reactive group conversion group Y ² which can be converted to the acid-reactive group Y ¹ was polymerized according to the process of the invention, after introducing the polymer, thus acid-reactive object to polymer reaction also obtained by converting the group Y ^1.

It is a method of introducing converted to the acid-reactive group Y ¹ of the object by a polymer reaction, for example, the formula:

CX ⁵ X ⁶ = CX ⁷ -OCR

 II

 〇

(Wherein, X ⁵ and X ⁶ are H or F; X ⁷ is H, CH ₃ or CF ₃ ; R is an alkyl group having 1 to 5 carbon atoms or a fluorine-containing alkyl group). The monomer having an acidic group-converting group (ester group) Y ² ) is copolymerized with m 1 and / or m 2 by the production method of the present invention to obtain a fluorine-containing polymer having an acid-reactive group converting group Y ² manufacture, and a method of converting the obtained fluorine-containing polymer of acid-reactive group conversion group Y ² to 〇_H group by causing alkaline hydrolysis (acid-reactive group Y ¹⁾ and the like.

The present invention also includes a method for producing a fluoropolymer that having a acid-reactive group Y ¹ via the process of polymer reaction.

In any case, according to the production method of the present invention, a fluoropolymer having an acid-reactive group Y ¹ can be efficiently obtained, and transparency in the vacuum ultraviolet region can be improved.

The fluorine-containing polymer having the acid-reactive functional group Y is a monomer having the acid-reactive functional group Y among the above-mentioned monomers (ml), or a monomer capable of providing an aliphatic ring structure. A monomer (m2-2) or (m2_4) having a reactive functional group Y or a cyclopolymerizable divinyl compound (m2-5) having an acid-reactive functional group Y It can be obtained by radical polymerization of at least one kind using a fluorine-containing polymerization initiator.

 Alternatively, when a monomer having no acid-reactive functional group Y is used as the monomer (ml) and (m2), the monomer (nl) having the acid-reactive functional group Y is converted into a monomer (ml) ) And (m2), may be copolymerized, and a third repeating unit (N1) having an acid-reactive functional group Y may be introduced in addition to the repeating units (Ml) and Z or (M2).

 As the monomer (nl) capable of introducing an acid-reactive functional group Y into any structural unit (N1), an ethylenic monomer having a copolymerizable acid-reactive functional group Y is preferable.

 Specifically, an acrylic monomer having an acid-reactive functional group Y, a fluorinated acryl-based monomer having an acid-reactive functional group Y, and an aryl ether-based monomer having an acid-reactive functional group Y , A fluorinated aryl ether monomer having an acid-reactive functional group Y, a vinyl ether monomer having an acid-reactive functional group Y, a fluorinated bierether monomer having an acid-reactive functional group Y Are preferred. More specifically,

(Meth) acrylic acid, α-fluoroacrylic acid, 1-trifluoromethyl acrylate, t-butyl (meth) acrylate, t-butyl-1-α-fluoroacrylate, t-butyl-α-trifluoromethyl acrylate , CH ₂ = CHCH ₂ Y, CH ₂ = CHCH ₂ OCH ₂ CH ₂ Y,

Formula:

CX ¹ X ² = CX ³ -CX ⁴ ₂ )- _¥ -(0- ^ R f -Y

(Wherein X ¹ and; X ² are the same or different, and both are H or F; X ³ _n — _m

 PCT / JP2003 / 0H605

28 is H, F, CH ₃ or CF ₃ ; X ⁴ is H, F or CF ₃ ; R f is a fluorinated alkylene group having 1 to 40 carbon atoms or a fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms A is 0 or an integer of 1 to 3; b is a fluorine-containing ethylenic monomer represented by 0 or 1);

 In particular, the formula:

CH ₂ = CF-CF ₂ 0-R f -Y

 (Wherein R f is the same as described above).

 More specifically,

CH ₂ = CFCF ₂ OCF-Y, CH ₂ = CFCF ₂ OCFCF ₂ OCF- Y

CF ₃ CF ₃ CF ₃

CH ₂ = CFCF ₂ 0 (CFCF ₂ 0) ₂ CF-Y,

CF ₃ CF ₃ CH ₂ = CFCF ₂ OCH ₂ CF ₂ — Y, CH ₂ = CFCF ₂ OCH ₂ CF ₂ CF ₂ OCF-Y,

 I

CF ₃

CH, = CFCF ₂ OCF ₂ CF ₂ OCF ₂ -Y, CH ₂ = CFCF ₂₀ (CF ₂ CF ₂₀ ) ₂ CF ₂ -Y

Preferred are fluorine-containing aryl ether compounds.

 Also, the formula:

CF ₂ = C F-0-R f one Y

(In the formula, Rf is the same as described above) „～ ™

 PCT / JP2003 / 011605

29 Preferred.

 More specifically,

CF ₂ = CFOCF ₂ CFOCF ₂ CF ₂ CH ₂ -Y,

CF ₃

CF ₂ = CFO (CF ₂ "HY, CF ₂ = CFO ~ (F ₂ " HCH ₂ -Y,

CF ₂ = CFOCF ₂ CF ₂ OCF ₂ -Y,

CF ₂ = CFOCF ₂ CF ₂ OCF ₂ CH ₂ -Y,

CF ₂ = CFOCF ₂ CF ₂ CH ₂ OCF ₂ CF ₂ -Y,

CF ₂ = CFOCF ₂ CF ₂ CH ₂ OCF ₂ CF ₂ CH ₂ -Y,

CF ₂ = CF〇CF ₂ CF〇CF ₂ CF ₂ CH ₂ — Y

Fluorinated Pinirue one ether compound such as CF ₃ and the like.

 Other fluorine-containing ethylenic monomers containing an acid-reactive functional group Y include:

CF ₂ = CF—CF ₂ 〇 一 R f — Y, CF ₂ = CF-R f-Υ,

CH ₂ = CH— Rf-Y, CH ₂ = CH-0-R f -Y

 (R f is the same as above)

And more specifically, more specifically,

Listen to PC 11605

 30

CF ₂ = CFCF ₂ OCF ₂ CF ₂ CF ₂ -Y, CF ₂ = CFCF ₂ OCF ₂ CF ₂ CF ₂ CH ₂ -Y,

CF ₂ = CFCF ₂ OCF ₂ CF—: Y, CF ₂ = CFCF ₂ OCF ₂ CF— CH ₂ — Y

 I I

CF ₃ CF ₃

CF ₂ = CFCF ₂ -Y, CF ₂ = CFCF ₂ CH ₂ -Y,

CH ₂ = CHCF ₂ CF ₂ CH ₂ CH ₂ -Y, CH ₂ = CHCF ₂ CF ₂ -.Y,

CH ₂ = CHCF ₂ CF ₂ CH ₂ -Y, CH ₂ = CHCF ₂ CF ₂ CF ₂ CF ₂ -Y, CH ₂ = CHCF ₂ CF ₂ CF ₂ CF ₂ CH ₂ — Y,

CH ₂ = CHO-CH ₂ CF ₂ CF ₂ -Y,

CH ₂ = CHOCH ₂ CF ₂ CF ₂ CH ₂ — Y, and the like.

 In the production method of the present invention, different properties such as mechanical strength and paintability are improved in the fluorine-containing copolymer from which the radically polymerizable monomer (n) can be obtained as an arbitrary monomer. It may be copolymerized for the purpose.

 Such an optional monomer (n) is selected from those which can be copolymerized with a monomer for constituting another structural unit.

 For example,

Acrylic monomer (excluding the monomer described in n1):

CH ₂ = CXCOOH CH ₂ = CXCOOCH ₂ CHCH ₂

 O

CH ₂ = CXCOOCH ₂ CH ₂ OH CH ₂ = CXCOO- <>

CH _? = CXCO

CH ₂ = CXCOO- ^ H ^

(X: H CH ₃ F CF ₃ ) Styrene monomer:

OH,

 (n 02 ^) Ethylene monomer:

CH ₂ = CH ₂ CH ₂ = CHCH ₃ CH ₂ = CHC 1 etc.

Maleic acid monomer: CH = CH CH = CH

 0 = C. C = 0 HOOC COOH

 〇

CH = CH CH = CH

 COOR COOH COOR COOR

 (R is a hydrocarbon group with 120 carbon atoms)

Aryl monomer:

CH ₂ = CHCH ₂ C 1 CH ₂ = CHCH ₂ OH CH ₂ = CHCH ₂ COO H CH ₂ = CHCH ₂ Br, etc.

Allyl monomer:

 (R: number of carbon atoms: hydrocarbon group of ~ 20) (n: 110 X: H C 1 F)

CH ₂ = CH CH ₂ 0 CH ₂ CH ₂ COOH

CH 2 ⁼ ^ i C i "12 O HCh.2 r 2 HCri O H2 h

 \ / I I

O OH OH

Other monomers:

CH ₂ = CH〇R, CH ₂ = CHOC—R,

 II

 O

 (R is an alkyl group having 1 to 20 carbon atoms which may be substituted by fluorine) More specifically,

CH ₂ = CH0 CH _Z ½H, CH ₂ = CHO ~ C),

CH ₂ =, CH ₂ = CHOC- (CH ₂ -)- _n H,

 O

CH ₂ = CH0C-> ^ CH ₂ = CHOC → (H

 o o

CH ₂ = CH0 CHCH ₂ O CH ₂ ^- _{; r} H,

 I

 x

(n: l~20, n ': 0~5, X: H or CH _3), and the like.

 In the present invention, an ethylenic monomer having 2 or 3 carbon atoms and having at least one fluorine atom (ml), or an aliphatic ring structure can be provided in the polymer main chain. Comonomers (n) containing monomers (m 2-1) to (m 2-5) and, if necessary, an ethylenic monomer (n 1) having an acid-reactive functional group, (Co) polymerization is performed by various known methods using a radical polymerization initiator containing a fluorine atom.

Polymerization methods include solution polymerization in an organic solvent that dissolves monomers, suspension polymerization in an aqueous medium in the presence or absence of a suitable organic solvent, and addition of an emulsifier to an aqueous medium. For example, an emulsion polymerization method carried out, a park polymerization method carried out without a solvent, and the like can be used. Among them, solution polymerization using organic solvents, 00 Hire 1605

34 Suspension polymerization is preferred.

 The polymerization solvent is not particularly limited, but a hydrocarbon solvent, a fluorine solvent (fluorocarbon), a chlorine solvent, an alcohol solvent, a ketone solvent, an ester acetate solvent, an ether solvent, or the like is preferably used. .

 Among them, fluorine-based solvents and chlorine-based solvents are preferred in that they have good solubility of monomers and initiators, and that they can promote the polymerization reaction well. Specifically, it is preferable to use one or two or more kinds selected from hydrated fluorocarbons, hydrated carbons, fluorocarbons, and hydrofluorocarbons.

 The polymerization is initiated by contacting the fluorinated radical polymerization initiator with a monomer and applying heat (at a temperature specific to the initiator) or irradiating active energy rays such as light or ionizing radiation.

 The composition of the resulting copolymer can be controlled by the composition of the monomers to be charged.

 The molecular weight can be controlled by the concentration of the monomer used for the polymerization, the concentration of the polymerization initiator, the concentration of the chain transfer agent, and the temperature.

 The amount of the fluorine-containing radical polymerization initiator to be used with respect to the monomer to be used is from 0.05 to 10 parts by weight, preferably from 0.01 to 5 parts by weight, per 100 parts by weight of the monomer. Preferably it is 0.1 to 1 part by weight. From another viewpoint, the fluorine-containing radical polymerization initiator is contained in an amount of 0.01 to 10 mol%, preferably 0.05 to 5 mol%, more preferably 0 to 10 mol% based on the molar amount of the monomer used. 1 to 2 mol%.

If the amount of the fluorinated radical polymerization initiator is too small, the polymerization reaction hardly proceeds sufficiently, unreacted monomers remain, or oligomer components are formed, which is not preferable because the coloring and transparency of the polymer decrease. If the amount of the fluorine-containing radical polymerization initiator is too large, the molecular weight of the polymer is reduced, and the transparency is reduced or unreacted. This is not preferable because the polymerization initiator remains and causes the coloring of the polymer and the decrease in transparency.

 The reaction temperature in the polymerization using the fluorinated organic peroxide as the radical polymerization initiator depends on the respective 10-hour half-life temperature of the fluorinated organic peroxide to be used, and further according to the target reaction time. Although it can be appropriately selected, it is generally 0 to 150 ° (: preferably 5 to 120 ° C, more preferably 10 to 100 ° C.

 The composition of the monomers to be copolymerized may be selected in accordance with the polymerization reactivity of each monomer, the copolymerization reaction ratio, and the properties imparted to the obtained fluoropolymer. The properties that each monomer can give to the fluoropolymer are as described above. More specifically, it will be described later.

 The fluoropolymer obtained by the production method of the present invention has high transparency with respect to light in the vacuum ultraviolet region having a wavelength of 20 O nm or less. Therefore, the Ar F excimer laser (193 nm) and F 2 It is a resist polymer that is particularly useful for photolithographic processes using a laser (157 nm).

 The present invention further provides

(A-1) OH group, an acid-dissociable functional group that can be converted to an OH group with an acid, or at least one acid of a CO OH group or an acid-dissociable functional group that can be dissociated with an acid to change to a CO OH group fluoropolymer having a reactive group Y ^1,

 (B) a photoacid generator, and

 (C) Solvent

For a composition consisting of

The present invention relates to a photoresist composition, wherein the fluoropolymer (A-1) is a polymer obtained by the above-mentioned production method of the present invention.

In the photoresist composition of the present invention, the acid-reactive functional group Y is dissociated with an OH group, an acid-dissociable functional group that can be converted to a 〇H group with an acid, Fluoropolymer having a specific acid-reactive group Y ¹ called at least one acid labile functional group which can be converted to a COOH group (A- 1) to use. As the acid dissociable functional group that can be converted to an OH group with an acid and the acid dissociable functional group that can be converted to a COOH group with an acid, those described above can be employed.

Examples of the fluorine-containing polymer (A- 1) having a specific acid-reactive group Y ^1, one technique of polymers are preferred.

 Equation (I):

 -(Ml) one (M2-2) one

(Wherein, Ml is a structural unit derived from a monomer (m 1) which is an ethylenic monomer having 2 or 3 carbon atoms and has at least one fluorine atom; M 2-2 is a monocyclic aliphatic fluorine-containing polymer Ru indicated in the structural unit) derived from which may monomer have a fluorine atom (the M2-2 a) having an acid-reactive group Y ¹ in the unsaturated hydrocarbon compound.

 The composition ratio of the structural units (Ml) and (M2-2) is usually 80 20 to 20/80 mol% ratio, preferably 70/30 to 30/70 mol% ratio, particularly preferably 60 Z 40 to 40 mol%. The ratio is 60 mol%.

Specific examples of the monomer, those which are specific examples, and acid-reactive functional group Y is an acid reactive group Y ¹ of the embodiment of the monomer (m2_2) monomer described above (ml) It can be preferably exemplified.

 Equation (II):

 ― (Ml) one (M2-4) one

(Wherein, same as above Ml; (M2- 4) the above that having a acid-reactive group Y ¹ aliphatic double ring structure-containing monomer (M2-4 a), particularly norbornene derivatives - derived A fluoropolymer represented by the following structural unit:

The composition ratio of the structural units (Ml) and (M2-4) is usually 80Z20-20 / 80 mol% ratio, preferably 70 / 30-30 / 70 mol% ratio, especially Preferably, the ratio is 60/40 to 40/60 mol%.

Specific monomers, illustrative examples, and monomer (The M2-4) acid-reactive functional group Y is an acid reactive group Y ¹ of the embodiment of the monomers described above (ml) Are preferably exemplified.

 These fluorine-containing polymers (I) and (II) are excellent in transparency and resistance to drying in themselves, and are further produced in a vacuum ultraviolet region by the production method of the present invention using a fluorine-containing polymerization initiator. Can improve transparency.

 Formula (III):

1 (Ml) 1 (M2-1)-(N1)-(wherein, M1 is the same as above; M2_1 has a polymerizable carbon-carbon unsaturated bond in a ring structure and has an acid-reactive function. monomers monocyclic having no group Y (m2- 1) structural units derived from; n 1 is copolymerizable Echire down monomers having an acid-reactive group Y ¹ (n ¹ a) from A fluoropolymer represented by the following formula: The composition ratio of the structural units (Ml), (M2—1), and (N1) is (Ml) + (M2-1) + (N1) = 100 mol%, and (Ml) + (M2 — 1) / (N 1) is usually a 90/10 to 20/80 mol% ratio, preferably an 80/20 to 30/70 mol% ratio, particularly preferably a 7030 to 4060 mol% ratio.

Specific examples of the monomer include the above-mentioned specific examples of the monomers (ml) and (m2−l) and the specific examples of the monomer (n1), in which the acid-reactive functional group Y is acid-reactive. what is group Y ¹ it can be preferably exemplified.

 Formula (IV):

 One (Ml) — (M2- 3)-(N 1) ―

(Wherein M1 and N1 are the same as described above; M2-3 has an acid-reactive functional group Y and has a structure derived from an aliphatic bicyclic structure-containing monomer (m2-3), particularly a norpolenene derivative. A fluoropolymer represented by the following formula: The composition ratio of the structural units (Ml), (M2-3), and (N1) is (Ml) + (M2-1) + (N1) = 100 mol%, and (Ml) + (M2- 1) / (N 1) is usually a 90/10 to 20/80 mol% ratio, preferably an 80/20 to 30/70 mol% ratio, particularly preferably a 70Z30 to 40/60 mol% ratio.

Specific examples of the monomer include the above-mentioned specific examples of the monomers (ml) and (m2-3) and the specific examples of the monomer (nl), wherein the acid-reactive functional group Y is an acid-reactive group. what is Y ¹ it can be preferably exemplified.

 Equation (V):

 -(M2-5) one (N 1) one

 (Wherein, N1 is the same as described above; M2-5 is a structural unit having a ring structure formed in a polymer main chain obtained by cyclizing and polymerizing a non-conjugated divinyl compound). .

 The composition ratio of the structural units (M2-5) and (N1) is usually 80/20 to 20/80 mol% ratio, preferably 70Z30 to 30Z70 mol% ratio, particularly preferably 60 to 40 to 40 to 60 mol. % Ratio.

Specific examples of the monomer include the specific examples of the aforementioned monomer (m 2-5) and the specific examples of the monomer (nl), wherein the acid-reactive functional group Y is an acid-reactive group Y ¹ Some of them are preferably exemplified.

These fluorine-containing polymers (III), (IV) and (V) are excellent in dry etching resistance themselves, and are further evacuated by the production method of the present invention using a fluorine-containing polymerization initiator. The transparency in the ultraviolet region can be improved. The acid reactive group Y ¹ fluorine-containing polymer (I) ~ (V) is different from the conventional Regis Bok for fluorinated polymers in that it has a fluorine-containing polymerization initiator residue in the polymerization initiation terminal Excellent in transparency especially in the vacuum ultraviolet region.

In the photoresist composition of the present invention,含Fu having acid reactive groups Y ¹ The nitrogen polymer (A-1) has excellent transparency at a wavelength of 157 nm, and has an extinction coefficient at 157 nm of 2.0 im- ¹ or less, preferably 1.5 m- ^1. The following, particularly preferably 1.0 m- ¹ or less, more preferably 0.5 ^ m- ¹ or less, the lower the extinction coefficient at 157 nm wavelength, the more the F2 photoresist composition This is preferable in that a good resist pattern can be formed.

 In the photoresist composition of the present invention, as the photoacid generator (B), those similar to the photoacid generator (B) described in WO01 / 74916 pamphlet can be similarly preferably exemplified, The present invention can also be used effectively. Specifically, it is a compound that generates an acid or a cation by irradiating light, and is, for example, an organic halogen compound, a sulfonate, or an ionic salt (in particular, the central element is iodine, io, selenium, tellurium) , A nitrogen or phosphorus fluoroalkylonium salt), a diazonium salt, a disulfone compound, a sulfonediazide, and the like, or a mixture thereof. The following are more specific examples.

 (1) TPS system:

(Wherein, X- is PF _{6 one, SbF 6 -, CF 3 S0} 3 -, C 4 F 9 S0 3 - , etc.; _{R la,} R _lb, Ric are the same or different, CH ₃ 〇, H, t one Bu, CH _3,

OH etc.)

(2) DP I system:

(Wherein, X- is CF ₃ SO, C ₄ F ₉ S_〇 _three to, CH ₃ - .psi. S0 ₃ one, S b

F

R ^2a , R ^2b are the same or different, H, OH, CH ₃ , CH ₃₀ .t-Bu, etc.)

 (3) Diazomethane type:

ON ₂ 〇

 II II II

R ^3a -S -CS -R ^3b

 II II

 o o

(Where R ^3a and R ^3b are the same or different,

Bu Bu, (Ή

Such)

(4) Sulfonate type:

( ^Where R ^4a is

CH _5-

Such)

The content of the photoacid generator in the photoresist composition of the present invention, the fluorine-containing polymer having an acid-reactive group Y ¹ (A- ¹⁾ is preferably 0.1 to 30 parts by weight per 100 parts by weight, Further, the amount is preferably 0.2 to 20 parts by weight, and most preferably 0.5 to 10 parts by weight.

 When the content of the photoacid generator is less than 0.1 part by weight, the sensitivity is lowered. When the content is more than 30 parts by weight, the amount of the photoacid generator absorbing light increases, and the light does not reach the substrate sufficiently. Resolution is likely to be reduced.

 Further, the photoresist composition of the present invention may contain an organic base capable of acting as a base with respect to the acid generated from the photoacid generator. As the organic base, those similar to those described in WO 01/74916 pamphlet can be preferably exemplified, and can be effectively used in the present invention.

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

 Specific examples include preferably butylamine, dibutylamine, triptylamine, 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. If it is less than 0.1 mol%, the resolution tends to be low, and if it is more than 100 mol%, the sensitivity tends to be low.

 In addition, if necessary, additives described in WO 01/74916 pamphlet, such as dissolution inhibitors, sensitizers, dyes, adhesion improvers, and water retention agents may be added to the photoresist composition of the present invention. For example, various additives commonly used in this field can be contained.

 In the photoresist composition of the present invention, the solvent (C) is preferably the same as the solvent (C) described in WO 01/74916 pamphlet, and can be effectively used in the present invention. .

Specifically, a cellosolve solvent, an ester solvent, a propylene glycol solvent, a ketone solvent, an aromatic hydrocarbon solvent, or a mixed solvent thereof is preferable. Further the fluorine-containing polymer (A- 1) solubility for high Mel, fluorine, such as fluorinated carbon hydrocarbon solvents and fluorine alcohols such as _{CH 3 CC 1 2 F (HC} FC- 141 b) A solvent may be used in combination. The amount of these solvents (C) is selected depending on the type of solid content to be dissolved, the substrate to be coated, the target film thickness, etc., but from the viewpoint of ease of application, the total solid content of the photoresist composition is high. It is preferable to use such that the partial concentration is 0.5 to 70% by weight, preferably 1 to 50% by weight.

The photoresist composition of the present invention is used in a conventional method of forming a resist pattern in a photoresist technique. Especially resist pattern forming method First, a solution of the photoresist composition is coated on a support such as silicon A8 using a spinner or the like, and dried to form a photosensitive layer. Irradiation with ultraviolet rays, deep-UV, excimer laser, or X-rays through a desired mask pattern or drawing with an electron beam and heating. Then add this to the developer, for example: Develop using an aqueous alkaline solution such as a 10% by weight aqueous solution of tetramethylammonium hydroxide. With this forming method, an image faithful to the mask pattern can be obtained.

 In particular, it has been found that a highly transparent resist film (photosensitive layer) can be formed even in the vacuum ultraviolet region by using the photoresist composition of the present invention. As a result, it can be used favorably in the photolithography process using an F 2 laser (157 nm wavelength), which is being developed with the aim of 0.07 xm technology in the future.

 The coating film coated with the photoresist of the present invention is formed by applying the above-described photoresist composition on a support such as a silicon wafer by a coating method such as spin coating, and drying the coating. It contains solid components such as a fluoropolymer having an acid-reactive group (A-1), a photoacid generator (B), and other additives.

 The thickness of the resist film to be formed is usually a thin film of 1.0 // m or less, preferably a thin film of 0.01 to 0.5 m, more preferably 0.05 to 0.5 m. .

Further, the coating film coated with the photoresist composition of the present invention preferably has high transparency in the vacuum ultraviolet region, and specifically has an absorption coefficient at a wavelength of 157 nm of 2.5 m- ¹ or less. Is preferably 2.0 m- ¹ or less, particularly preferably 1.50 m- ¹ or less, and further preferably 1.0 m- ¹ or less. This coating is lithographic using an F 2 laser (157 nm). It can be used effectively for roughing processes.

 As the substrate on which the resist coating is applied, various types of substrates to which a conventional resist is applied can be similarly used. For example, it may be a silicon wafer, a silicon wafer provided with an organic or inorganic antireflection film, a glass substrate, or the like. Particularly, the sensitivity and the profile shape on a silicon wafer provided with an organic antireflection film are good.

Further, the present inventors conducted a study by focusing on the structure of the main chain terminal of the fluoropolymer, and found that in a specific fluoropolymer obtained by polymerizing tetrafluoroethylene and a norportene derivative. It has been found that a polymer in which CF ₃ groups are introduced at a high ratio exceeding a specific value at the polymer terminal can more effectively improve the transparency, particularly the transparency in vacuum ultraviolet light represented by 157 nm.

 Specifically, the novel polymer of the present invention has the formula (1):

One (M1A)-(M2A) — (N1A) —

(Wherein, Ml A is a structural unit derived from tetrafluoroethylene; M2 A is a structural unit derived from a norpornene derivative (m2a) which may contain a fluorine atom; N 1 A is tetrafluoroethylene And a monomer (n1a) -derived structural unit copolymerizable with a norpoleneene derivative (m2a), and the structural unit MlA is 12 to 70 mol% and the structural unit M2A is 12 to 70 mol%. Mole%, containing 0 to 60 mole% of structural unit Nl A, and when (M1A) + (M2 A) = 100, (Ml A) / (M2 A) is 30/70 to 70Z 30 mole% ratio A fluorine-containing polymer having a number average molecular weight of 1,000 to 50,000, wherein the polymer contains a polymer molecule having a CF ₃ group at at least one of the polymer main chain terminals, and is detected by ¹⁹ F-NMR analysis. It is an CF ₃ signal intensity of the polymer main chain terminal H (terminal CF ₃₎ is, that form a main strand single CF ₂ - signal strength H (- CF ₂ —) And the formula (1): 3011605

 45

0.3 ≥ H (terminal CF ₃ ) / H (one CF _2- ) ≥ 0.01 The fluoropolymer satisfies the relational expression of Formula (1).

Fluoropolymer polymer terminal is CF ₃ at a high ratio as described above, patent, are novel compounds not described in literature.

 Specifically, the fluoropolymer of the present invention is

(i) a polymer molecule having CF _{3 at} both ends,

(ii) polymer molecules one end is CF ₃ of, and

(iii) Polymer molecule without terminal CF ₃ group

May be a mixture of three types of polymer molecules, but a polymer molecule having at least one CF ₃ group at at least one terminal of the polymer main chain (the polymer (i) and / or (ii) above) (Molecules), and among them, those satisfying the relationship of Expression (1) are preferable.

Analysis one CF ₃ group of the polymer terminal, quantitation IR analysis, it is possible in a variety of instrumental analyzes such as NMR analysis, is preferably carried out using a NMR analysis in that it can accurately quantified. As shown in the examples below, the signal of the —CF ₃ group at the terminal of the polymer main chain is independent of the signal of the other F atom at around -80 to 84 ppm (standard of trichloro-fluorine). ¹⁹ F-NMR is particularly preferred in that it can be separated into

In the fluorinated polymer of the present invention, the value of H (terminal CF ₃ ) / H (—CF ₂ —) in the mathematical formula (1) is based on —CF ₂ — (for example, derived from tetrafluoroethylene) in the polymer main chain. It represents the ratio of _three main chain terminal CFs of the polymer to the above, and varies depending on the molecular weight of the fluoropolymer, but is preferably a large value in the above numerical range.

 Specifically, Equation (1) is replaced by Equation (1-1):

0.3 ≥H (terminal CF ₃ ) XH (one CF ₂ —) ≥0.02 It is preferable that the formula (1-1) is satisfied, Furthermore, the formula (1-2):

0.25≥H (terminal CF ₃ ) / H (-CF _2- ) ≥0.03 It is preferable that the formula (1-2) is satisfied.

In particular, equation (1-3):

0.2 ≥ H (terminal CF ₃ ) ZH (-CF _2- ) ≥ 0.05 It is preferable that the expression (1-3) is satisfied.

Although the fluorine-containing polymer of the present invention varies depending on the molecular weight, specifically, at least 40% of all terminals of the polymer main chain are preferably CF ₃ groups, more preferably at least 50%, Is preferably a polymer having a CF ₃ group introduced at the terminal of 70% or more, particularly 90% or more.

 Thereby, transparency can be improved more effectively.

 The norponene derivative (m2a) constituting the structural unit M 2 A in the fluoropolymer represented by the formula (1) of the present invention is a monomer (m2) of the monomer (m2) described in the above-mentioned method for producing a fluoropolymer. From the examples, those which are norpolene derivatives are also preferably selected.

 Specifically, the same monomers as those described above for the monomer having no acid-reactive functional group Y (m2-3) and the monomer having an acid-reactive functional group Y (m2-4) are preferable. Available.

 The structural unit NLA in the fluoropolymer represented by the formula (1) of the present invention is an optional component, and is a structural unit derived from a copolymerizable monomer other than tetrafluoroethylene and a norpolenene derivative. Specifically, a monomer (n1) capable of introducing an acid-reactive functional group Y described in the above-mentioned method for producing a fluoropolymer, and those similar to those described for the optional monomer (n) can be used. It can be used preferably.

In the fluorine-containing polymer represented by the formula (1) of the present invention, when the content ratio of the structural units MlA, M2A and N1A is M1A + M2A = 100, M1AZM2A is 80/20 to 2080 mol. % Ratio, preferably 70Z 30 3030/70 mol% ratio, more preferably 60 6040/40/60 mol% ratio. The content ratio of the optional component N 1 A to all structural units is 60 mol% or less, preferably 30 mol% or less, more preferably 20 mol% or less, further 10 mol% or less, and most preferably 0 mol%. It is.

 Therefore, the specific proportions of the structural units M 1 A, M 2 A and N 1 A are, specifically, 12 to 70 mol% of the structural unit M 1 A, 12 to 70 mol% of the M 2 A, and Nl A 0 to 60 mol%, preferably 21 to 70 mol% of the structural unit MlA, 21 to 70 mol% of the M2A, 0 to 30 mol% of the structural unit Ml A, more preferably 24 to 30 mol% of the structural unit Ml A ~ 70 mol%, M2A is 24 ~ 70 mol%, N1A is 0 ~ 20 mol%, and the structural unit MlA is 27 ~ 70 mol%, M2A is 27 ~ 70 mol%, 1 ^ 1 8 to 10 mol%, most preferably 30 to 70 mol% of the structural unit M1A, 30 to 70 mol% of M2A, and 0 mol% of N1A.

 The molecular weight of the fluoropolymer represented by the formula (1) of the present invention is 1000 or more in number average molecular weight, preferably 2000 or more, more preferably 2500 or more, 50,000 or less, preferably 30,000 or less, more preferably 10,000 or less. is there.

The fluorine-containing polymer of the present invention represented by the formula (1) is preferable because it has excellent transparency due to the effect of the terminal CF ₃ group even if it is a low molecular weight polymer. Various methods for obtaining a fluoropolymer having a main chain terminal CF ₃ group of the polymer of the present invention can be selected variously,

(1) A method for producing a polymer using a polymerization initiator capable of introducing a CF ₃ group into a terminal,

(2) a method for producing a polymer using a chain transfer agent capable of introducing a CF ₃ group into a terminal,

(3) The terminal of the fluoropolymer once produced is CF ₃ group How to convert to

Among them, the method of producing a polymer using a polymerization initiator (1) and the method of producing a polymer using a chain transfer agent (2) can selectively introduce CF ₃ groups into the terminal. It is preferred in that respect.

As a method of producing a polymer using a polymerization initiator (1), a polymerization initiator having a CF ₃ group is selected from the polymerization initiators containing a fluorine atom exemplified in the method of producing a fluorine-containing polymer. An agent is selected. For example, it is preferable to select a CF ₃ group-containing oxide from the preferred examples of the di (fluoroacyl) oxide described above.

 Next, the present invention will be described with reference to examples and the like, but the present invention is not limited to these examples and the like.

Example 1 (Synthesis of copolymer of TFE and fluorinated norbornene containing OH group (NB-1))

 A 500 ml autoclave equipped with a valve, a pressure gauge, a stirrer and a thermometer was replaced with nitrogen several times and then evacuated to obtain a fluorinated norbornene containing OH group (NB_1):

Of 49.0 g of HCFC-141b and 250m1. Then, TFE80. O g was charged from the valve, and 7H—

Monoxide (formula):

 O

II _Ί

[H (CF ₂ CF ₂ ) ₃ C〇] ₂ 28.0 g of a 8.0% by weight perfluorohexane solution was added thereto, and the mixture was stirred and reacted at 20 ° C. for 4 hours.

 After releasing the unreacted monomer, 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, and 3.5 g of a copolymer was obtained.

From the results of ¹ H—NMR and ¹⁹ F—NMR analysis, the copolymer had a copolymer weight ratio of TFE / the 〇H group-containing fluorinated norportene derivative (NB-1) of 50/50 mol%. It was united.

 GPC analysis revealed a number average molecular weight of 4,100.

Example 2 (Synthesis of Ding £ and -0_Rei_11 ₂ 00 ₂ 11 ₅ group containing norbornene induction body (NB 1 (1)), a copolymer)

In Example 1, in place of the fluorinated norbornene derivative containing 1 OH group (NB-1), a fluorinated norpoleneene derivative containing _OCH ₂ OC ₂ H ₅ group (NB-1 (1)):

The reaction was carried out in the same manner as in Example 1 except that 59.0 g of 50.0 g of 7H-dodecafluoroheptanyl peroxide and 52.0 g of a 8.0% by weight hexane solution of perfluorohexane were used. Done.

 After releasing the unreacted monomer, the polymerization solution was taken out, concentrated, and reprecipitated with methanol / water (1: 1) to separate the copolymer. Vacuum drying was performed until a constant weight was obtained to obtain 2.5 g of a copolymer.

The composition ratio of this copolymer is ^ Chromatography NMR and ¹⁹ F- from the results of NMR analysis, Ding £ / the chromatography 0 (: ^^ 0_Rei ₂ 11 ₅ group-containing fluorine-norbornene derived The copolymer (NB-1 (1)) was a 50Z50 mol% copolymer.

 GPC analysis revealed a number average molecular weight of 3,800.

EXAMPLE 3 (TFE and -OH group-containing fluorine-norbornene derivative (NB-1) and -〇_CH ₂ OC ₂ H ₅ group-containing fluorine-norbornene derivative (NB- 1 (1)) and the synthesis of copolymer)

80.0 g of TFE and 39.0 g of the OH-containing fluorine-containing norbornene derivative (NB-1) used in Example 1 and one OCH ₂ 2C ₂ H ₅ group used in Example 2 were used. The reaction was carried out in the same manner as in Example 2 except that 12.0 g of the fluoronorpoleneene derivative (NB-1 (1)) was used.

 After releasing the unreacted monomer, separation and purification were carried out in the same manner as in Example 1 to obtain 5.2 g of a copolymer.

From the results of ¹ H-NMR and ¹⁹ F-NMR analyses, the composition ratio of this copolymer was determined to be T FEZ—OH group-containing fluorinated norportene derivative (NB—1) / one OCH ₂ 〇C ₂ H ₅ group The content of the fluorine-containing norportene derivative (NB-1 (1)) was 50/40/10 mol%.

 GPC analysis revealed a number average molecular weight of 4,300.

Example 4 (Synthesis of copolymer of TFE and —O (C = 〇) 〇C (CH ₃ ) ₃ group-containing fluorinated norbornene derivative (NB-1 (2)))

In Example 2, instead of the ten CH ₂ 〇 C ₂ H ₅ group-containing fluorine-norbornene derivative conductor (NB- 1 (1)), _0 (C = 0) OC (CH 3) 3 group-containing organic fluorine Norponene derivative (NB-1 (2)):

PC orchid illustration

The reaction was carried out in the same manner as in Example 2 except that 66.0 g of 51 was used, followed by separation and purification to obtain 2.0 g of a copolymer.

The composition ratio of this copolymer was determined by ¹ H-NMR ¹⁹ F-NMR analysis to be TFE / the above 1 O (C = 〇) OC (CH ₃ ) ₃ group-containing fluorinated norpornene derivative (NB — 1 (2)) was a 50/50 mol% copolymer.

 GPC analysis revealed a number average molecular weight of 3,700.

Example 5 (Synthesis of TFE / (NB-1) / (NB-1 (2)) Copolymer)

80.0 g of TFE and 39.0 g of the fluorine-containing norportene derivative containing NBH group (NB-1) used in Example 1 and —〇 (C = 〇) OC (CH ₃ ) The reaction was carried out in the same manner as in Example 2 except that 13.2 g of the fluorine-containing norbornene derivative containing _three groups (NB-1 (2)) was used. After releasing the unreacted monomer, the product was separated and purified in the same manner as in Example 1 to obtain 5.2 g of a copolymer.

The composition ratio of this copolymer is as follows: — NMR and ¹⁹ F— From the results of NMR analysis, TFEZ—OH-containing fluorinated norportene derivative (NB-1) / 10 (C = 0) OC (CH ₃ ) ₃ The content of the fluorine-containing norportene derivative (NB-1 (2)) was 50Z41 / 9 mol%.

 GPC analysis revealed a number average molecular weight of 4,400. '

Example 6 (Synthesis of copolymer of TFE and fluorinated norpoleneene containing OH group (NB-2))

In Example 2, single 0 CH ₂ 〇 C ₂ H ₅ group containing norbornene derivative conductor (NB- 1 (1)) in place of one OH group-containing fluorine-norbornene (NB 2):

The reaction was carried out in the same manner as in Example 2 except that 55 g of Og was used. After releasing the unreacted monomer, it was separated and purified in the same manner as in Example 1 to obtain 4.3 g of a copolymer.

As a result of ¹ H_NMR and ¹⁹ F-NMR analysis, the composition ratio of this copolymer was such that TFE / the OH-containing fluorine-containing norportene derivative (NB-2) was 50 to 50 mol%. .

 GPC analysis revealed a number average molecular weight of 2,200.

Example 7 (Ding £ and _〇 (: 1 ^ ₂ 0 ₍₂ 1 ₅ group containing norbornene induction body (NB 2 (1)) Synthesis of copolymer of)

In a 100 ml autoclave equipped with a valve, a pressure gauge, a stirrer, and a thermometer—a fluorinated norpoleneene derivative containing _five OCH ₂ OC ₂ H groups (NB-1 (1)):

14.0 g, HCFC-141b in 50 ml, 7 H-dodecafluo to the mouth 11.0 g of 8.0 wt% perfluohexane hexane solution of neil peroxide was added, and dry ice Z methanol solution was added. While cooling with, the inside of the system was sufficiently replaced with nitrogen gas. Then, 15.O g of TFE was charged from the valve, and the mixture was reacted by shaking at room temperature for 18 hours. As the reaction progresses, the gauge pressure becomes before the reaction From 0.996MPaG (9.7 kgfcm ² G) to 0.91MPaG (9.2 kgf / cm ² G). Then, separation and purification were carried out in the same manner as in Example 2 to obtain 1.0 g of a copolymer.

The composition ratio of this copolymer was as follows: from the results of —NMR and ¹⁹ F—NMR analyses, it was found that TFE / the above-mentioned fluorinated norpolenene derivative (NB—2 (1)) containing a CH ₂ —C ₂ H ₅ group contained 50Z50 It was a mole% copolymer.

 GPC analysis revealed a number average molecular weight of 2,300.

Example 8 (Synthesis of copolymer of tetrafluoroethylene Z (NB-2) / (NB-2 (1)))

80 g and 1 8. _OCH ₂ OC ₂ H ₅ group-containing fluorine-norbornene derivatives used in 3 g of Example 7 one OH group-containing fluorine-norbornene derivative used in Example 6 (NB-2) of TFE ( The reaction was carried out in the same manner as in Example 2 except that 14.8 g of NB-2 (1)) was used. Then, separation and purification were carried out in the same manner as in Example 1 to obtain 4.7 g of a copolymer.

The composition ratio of this copolymer is based on the results of —NMR and ¹⁹ F—NMR analyses. From the results of TFE / —OH group-containing fluorinated norportene derivative (NB—2) / — OCH ₂ 〇C ₂ H ₅ group-containing fluorinated norpolenene The derivative (NB-2 (1)) was a copolymer of 50Z39 / 11 mol%.

 GPC analysis revealed a number average molecular weight of 2,400.

Example 9 (Synthesis of TFE-free OH-containing fluorinated norpoleneene (NB-1) copolymer)

A 50 Oml autoclave equipped with a valve, a pressure gauge, a stirrer and a thermometer was purged with nitrogen several times, and then evacuated to 39.0 g of fluorinated norportene containing OH group (NB-1) and HCFC. — 250 ml solution of 141b was charged. Next, 58.0 g of TFE was charged from the valve, and the amount of pen-fluoropropionyl peroxide: (CF.CF ₂ COO) ₂ 10 10.5 g of a 0.0% by weight hexane solution was added thereto, and the mixture was stirred and reacted at 35 ° C. for 3 hours.

 After releasing the unreacted monomer, 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 3.5 g of a copolymer.

The composition ratio of this copolymer was determined by T-NMR and ¹⁹ F-NMR analysis to be that the TFE / the above-mentioned mono-OH group-containing fluorinated norponene derivative (NB-1) was 50/50 mol%. Was.

 GPC analysis revealed a number average molecular weight of 3,700.

Example 10 (Synthesis of copolymer of TFE / —OH group-containing fluorinated norportene (NB-1))

A 500 ml autoclave equipped with a valve, a pressure gauge, a stirrer and a thermometer was purged with nitrogen several times, and then evacuated to 39.0 g of fluorinated norportene (NB-1) containing 10H group and HCFC. — 250 ml of a solution of 141 b was charged. Next, 58. O g of TFE was charged from the valve, and 17.0 g of a solution of 10.0% by weight of hexane perfluoropropionyl peroxide: (CF ₃ CF ₂ CF ₂ C〇〇) ₂ in peroxane was added. The mixture was stirred and reacted at 35 ° C. for 3 hours.

 After releasing the unreacted monomer, 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 3.4 g of a copolymer.

From the results of NMR and ¹⁹ F-NMR analyses, the copolymer had a composition of TFE / the above-mentioned mono-OH group-containing fluorinated norportene derivative (NB-1) having a molar ratio of 50Z50 mol%.

 GPC analysis revealed a number average molecular weight of 3,800.

Comparative Example 1 In Example 1, 6.5 g of bis (4-tert-butylcyclohexyl) peroxydicarbonate (TCP) as a radical polymerization initiator in place of 7H-dodecafluoroheptanyl peroxide was used. And the same operation as in Example 1 was carried out except that the reaction was carried out at 40 ° C. using 30.6 g of fluorine-containing norportene (NB-1) containing 1H group. 5.0 g of a copolymer of a fluorine norportene derivative (NB-1) was obtained.

The composition ratio of the copolymer is! As a result of ^ -NMR and ¹⁹ F-NMR analysis, TF-containing fluorine-containing norportene derivative (NB-1) was a copolymer of 50Z and 50 mol% in T FEZ.

 GPC analysis revealed a number average molecular weight of 4,700.

Comparative Example 2

In Example 2, instead of 7H-dodecafluoroheptanyl peroxide, 6.5 (bis- (4-tert-butylcyclohexyl)) peroxydiponic acid (TCP) was used as a radical polymerization initiator. (^ 1 ₂ hundred ₂ H ₅ group-containing fluorine-norbornene (NB 1 (1) in use Les 401 37. 0 g) of non-reacted performs the same operation as in example 2, TF 6.0 g of a copolymer of E and the _OCH ₂ OC ₂ H ₅ group-containing fluorinated norponene derivative (NB-1 (1)) was obtained.

As a result of NMR and ¹⁹ F-NMR analysis, the composition ratio of the copolymer was such that 50/50 mol% of TFEZ-containing fluorine-containing norportene derivative (NB-1 (1)) containing 50% CH ₂ OC ₂ H ₅ was used. It was a copolymer.

 GPC analysis revealed a number average molecular weight of 4,600.

Comparative Example 3

In Example 3, 6.5 g of bis (4-tert-butylcyclohexyl) peroxide-ponate (TCP) was used as the radical polymerization initiator in place of 7H-dodecafluoroheptanyl peroxide. One used in Example 1 T / JP2003 / 011605

 56

39.0 g of OH-containing fluorinated norportene (NB-1) and 12.O g of the 〇CH ₂ 〇C ₂ H _5- group-containing fluorinated norpolene (NB-1 (1)) used in Example 2 The reaction was carried out in the same manner as in Example 3 except that the reaction was carried out at 40 ° C. using TFE, and the TFE, the fluorine-containing norponene derivative containing 1H group (NB-1), and the OCH ₂ OC ₂ H ₅ 5.2 g of a terpolymer of a group-containing fluorinated norportene derivative (NB-1 (1)) was obtained.

The composition ratio of the copolymer, - NMR and ¹⁹ F- NMR results of the analysis, T FEZ-〇_H fluorine-containing norbornene derivative (NB 1) / one OCH ₂ OC ₂ H ₅ group-containing fluorine-norbornene derivative ( NB-1 (1)) was a copolymer of 50 / 40Z10 mol%.

 GPC analysis revealed a number average molecular weight of 4000.

Comparative Example 4

In Example 4, 6.5 g of bis (4-tert-butylcyclohexyl) hydroxyl-ponate (TCP) as a radical polymerization initiator instead of 7H-dodecafluoroheptanyl peroxide was used. Example 4 Example 4 was repeated except that the reaction was carried out at 4 O ^ C using 41.6 g of a fluorine-containing norponene derivative containing _three O (C = 〇) OC (CH ₃ ) ₃ groups (NB-1 (2)). The same operation as described above was performed to obtain 6.O g of a copolymer of TFE and the above-mentioned mono-O (C = 〇) OC (CH ₃ ) ₃ group-containing fluorine-containing norportene derivative (NB-1 (2)). .

As a result of the analysis, the composition ratio of the copolymer was determined to be 50/0 mol% of the T FEZ mono-O (C = 0) OC (CH ₃ ) ₃ group-containing fluorine-containing norportene derivative (NB-1 (2)). It was a polymer.

 GPC analysis revealed a number average molecular weight of 3,300.

Comparative Example 5

In Example 5, bis (4-tert-butylcyclohexyl) was used as a radical polymerization initiator in place of 7H-dodecafluoroheptanyl peroxide. ) 6.5. And 0.13 of fluorine-containing norportene derivative (NB-1) containing 0.11 and 0.16 groups of phosphidic acid (TCP) 30.68 and 0 (C = 〇) 〇C (CH ₃ ) ₃ groups The same operation as in Example 5 was carried out except that the reaction was carried out at 40 using 8.3 g of the fluorinated norportene derivative (NB-1 (2)), and the TFE and the -OH group-containing 6.8 g of a ternary copolymer of a fluorine-containing norportene derivative (NB-1) and the above-mentioned _0 (C = 〇) OC (CH ₃ ) ₃ group-containing fluorine-containing norpoleneene derivative (NB-1 (2)) was obtained. .

As a result of analysis, the composition ratio of the copolymer was found to be TFE / —OH group-containing fluorinated norbornene derivative (NB-1) / — O (C = 〇) OC (CH ₃ ) _3- group-containing fluorinated norbornene derivative (NB — 1 (2)) was a 50/39/1 1 mol% copolymer.

 GPC analysis revealed a number average molecular weight of 2,900.

Comparative Example 6

 In Example 6, 6.5 g of bis (4-t-butylcyclohexyl) peroxydicarbonate (TCP) as a radical polymerization initiator in place of 7 H-dodecafluoroheptanyl peroxide and — The same operation as in Example 6 was carried out except that 34.6 g of the OH-containing fluorine-containing norportene derivative (NB-2) was reacted at 40 ° C. 4.5 g of a copolymer of a fluorine-containing norportene-containing derivative (NB-2) was obtained. As a result of analysis, the composition ratio of the copolymer was TFE / the above-mentioned mono-OH-containing fluorinated norportene derivative (NB-2), which was a 50Z50 mol% copolymer.

 GPC analysis revealed a number average molecular weight of 2,100.

Comparative example Ί

In Example 7, 1.3 g of bis (4_t-butylcyclohexyl) peroxydicarbonate (TCP) as a radical polymerization initiator in place of 7 H-dodecafluoroheptanyl peroxide and 1 OCH ₂ 〇C _{2 PC} listening 麵麵

58

The same operation as in Example 7 was carried out except that 9.3 g of the fluorine-containing norpolenene derivative containing H ₅ group (NB-2 (1)) was reacted at 40 ° C. 1.0 g of a copolymer of a fluorinated norpoleneene derivative (NB-2 (1)) containing a CH ₂ 〇C ₂ H ₅ group was obtained.

As a result of analysis, the composition ratio of the copolymer was found to be TZ50 / 50 mol% (50-2% by mole) TFE / the above-mentioned fluorinated norponene derivative containing a CH ₂ OC ₂ H ₅ group (NB-2 (1)).

 GPC analysis revealed a number average molecular weight of 2,200.

Comparative Example 8

In Example 8, 6.5 g of bis (4_t-butylcyclohexyl) peroxydicarbonate (TCP) was used as a radical polymerization initiator in place of 7H-dodecafluoroheptanyl peroxide, and with 8. 2 g of 27. 7 g as an OCH ₂ OC ₂ H ₅ group-containing fluorine-norbornene derivative (NB- 2 (1)) of the OH group-containing fluorine norbornene derivative (NB- 2), 40 ° except reacted at C is performed in the same manner as in example 8, the said and TFE one 〇_H fluorine-containing norbornene derivative (NB-2) one 〇_CH ₂ 〇_C ₂ H ₅ group-containing free 5.2 g of a ternary copolymer of a fluorine-norpolenene derivative (NB-2 (1)) was obtained.

The composition ratio of the copolymer as a result of the analysis, TFE / - OH group-containing fluorine-nor bornene derivatives (NB- 2) Z-〇_CH ₂ OC ₂ H ₅ group-containing fluorine-Norupo Runen derivative (NB- 2 (1 )) Is a 50/40/10 mol% copolymer.

 GPC analysis revealed a number average molecular weight of 2,300.

Example 11 (transparency measurement at 157 nm)

(Measurement device) VU-201 type vacuum ultraviolet spectroscopy system (manufactured by Spectrometer Co., Ltd.) Each of the fluoropolymers obtained in Examples 1 to 10 was dissolved in PGMEA to prepare a 10% solution.

Using a spin coater, the solution was applied to a C a F ₂ on the substrate, and dried at 1 10 ° C, to prepare a film thickness of about 90 to 200 nm of the coating.

 (Transparency measurement)

The absorbance at 157 nm was measured with the above-mentioned spectrophotometer using a C a F ₂ substrate coated with each fluoropolymer film, and the extinction coefficient was calculated from the film thickness of each film.

 Table 1 shows the results.

Comparative Example 9 (transparency measurement at 157 nm)

 In the same manner as in Example 11 except that the fluorinated polymer obtained in Comparative Examples 1 to 8 was used instead of the fluorinated polymer obtained in Examples 1 to 10, preparation of a coating film at 157 nm Transparency measurements were taken.

 Table 1 shows the results.

 table 1

 Example 11 Comparative Example 9 Fluorinated polymer 157 nm extinction coefficient Fluorinated polymer 157 nm extinction coefficient

(— ¹ )

 Example 1 0.40 Comparative Example 1 0.93 Example 2 0.61 Comparative Example 2 1.00 Example 3 0.38 Comparative Example 3 0.76 Example 4 2.40 Comparative Example 4 3.00 Example 5 1.00 Comparative Example 5 1.96 Example 6 0.60 Comparative Example 6 1.80 Example 7 0.80 Comparative Example 7 1.90 Example 8 0.70 Comparative Example 8 1.70 Example 90 . 39

Example 10 0.38 Example 12 (Measurement of solubility in developer)

 Using the fluoropolymer obtained in Example 1 or Example 6, the dissolution rate was measured by the quartz oscillator method (QCM method) as described below.

 (1) Preparation of sample: A solution of the fluoropolymer obtained in Example 1 (or Example 6) dissolved in PGME A was applied to a 1-inch-diameter quartz crystal plate coated with gold, and applied for about 100 minutes. A nm coating was prepared.

 (2) Measurement of dissolution rate: The film pressure is converted and measured by the frequency of the quartz oscillator. The quartz crystal plate coated with the fluoropolymer is immersed in a 2.38% by weight aqueous solution of tetramethylammonium hydroxide (TMAH). The dissolution rate per unit time (nm / sec) was calculated by measuring the change in frequency.

 Table 2 shows the results.

 Table 2

Example 13

 To 100 parts by weight of the fluorinated copolymer obtained in Example 3, 5 parts by weight of triphenylsulfonium / perfluorobutylsulfonate as a photoacid generator was added, and the mixture was dissolved in PGME A to give a photosensitive solution. A composition was prepared. The photosensitive composition is applied on a silicon wafer coated with an anti-reflection film (manufactured by SHI PLEY, AR 19) to a thickness of 80 nm using a spin coater, dried at 110 ° C for 90 seconds, and dried to a thickness of 150 A nm resist film was formed.

Using a F2 excimer laser beam (wavelength: 157 nm), this resist film was subjected to frame exposure on a spot of 1 cm X 1 cm square (1 cm ² ). PT / JP2003 / 011605

 61 After the exposure, the film was heated on a hot plate at 110 ° C. for 90 seconds, and developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide (TMAH).

Similarly row Natsutatoko filtrate by changing the frame exposure, heating and development of the above exposure amount of F 2 laser beam from 0. lm J / cm ² to ^{100m J / cm 2, 2. 5m} JZcm 2 or more 1 cm ² spots were completely dissolved at the exposure dose. From this, it was found that the fluorinated copolymer obtained in Example 3 had sensitivity enough to function as a positive resist.

Patterning using a reduction projection exposure system (157 nm microstepper manufactured by Excitech: Le Venson Mask, ΝΑ / σ = 0.85 / 0.30 Conv.) Using an F 2 laser as a light source An evaluation was performed. As a result, a 1: 1 L / S fine pattern was produced at an exposure dose of 15 mJ / cm ² at 85 nm. From this, it was found that the fluororesin obtained in Example 3 had a resolution capable of functioning as a positive resist. Example 14

 A photosensitive composition was prepared in the same manner as in Example 13 except that the fluorinated copolymer obtained in Example 5 was used instead of the fluorinated copolymer obtained in Example 3, and a resist film was prepared. It was formed and subjected to frame exposure, heating, and development using a single F2 laser beam.

As a result, a spot of 1 cm ² was completely dissolved at an exposure amount of 1.3 mJ Zcm ² or more. From this, it was found that the fluorinated copolymer obtained in Example 5 had sensitivity enough to function as a poly-type resist.

As in Example 13, patterning evaluation was performed using a reduction projection exposure apparatus using an F2 laser as a light source. As a result, a fine pattern of 80 nm and 1: 1 LZS could be produced with an exposure amount of 12 mJ / cm ² . From this, the fluororesin obtained in Example 5 can function as a positive resist. It turned out that it has resolution.

Example 15

 A photosensitive composition was prepared in the same manner as in Example 13 except that the fluorinated copolymer obtained in Example 8 was used instead of the fluorinated copolymer obtained in Example 3, and a resist film was prepared. It was formed and subjected to frame exposure, heating, and development with F2 laser light.

As a result, a spot of 1 cm ² was completely dissolved at an exposure amount of 1.6 mJ / cm ² or more. From this, it was found that the fluorinated copolymer obtained in Example 8 had sensitivity enough to function as a poly-type resist.

As in Example 13, patterning evaluation was performed using a reduction projection exposure apparatus using an F2 laser as a light source. As a result, a fine pattern of 80 nm and 1: 1 L / S could be produced with an exposure amount of 27 mJ / cm ² . From this, it was found that the fluororesin obtained in Example 8 had a resolution capable of functioning as a positive resist.

Example 16 (Terminal CF ₃ analysis of fluoropolymer)

For Example 1, 9, 10 and the fluorine-containing polymer obtained respectively in Comparative Example 1 was measured terminal CF ₃ content as follows.

 The fluoropolymer powder was dissolved in deuterated acetone at 0.1 to 10% by weight, and it was confirmed that it was completely dissolved.

Using the polymer solution, NMR (apparatus: AC-300, manufactured by BRUKER) was performed at room temperature using trichlorofluoromethane as a chemical shift standard (Op pm) to obtain a ¹⁹ F-NMR chart.

^{From the 19} F-NMR data chart, signals at each site of the polymer were separated and detected at the chemical shift positions shown in Table 3.

The integrated value (area value) of the signal at the polymer terminal CF ₃ shown in Table 3 was defined as H (terminal CF ₃ ). The signal of CF _{2 in} the polymer main chain is shown in Table 3. A broad peak was obtained in such a wide chemical shift range, and the sum of the integrated values (area values) of the broad peak was defined as H (—CF ₂ —).

Table 4 shows the value of H (terminal CF ₃ ) / H (one CF ₂ —) from the calculated H (terminal CF ₃ ) and H (—CF ₂ —). Table 3

Industrial applicability

 According to the production method of the present invention, it is possible to produce a fluoropolymer having excellent transparency in a vacuum ultraviolet region and capable of forming an ultrafine pattern for a photoresist, particularly for an F 2 resist.

Claims

The scope of the claims

1. A repeating unit (Ml) and Z or a polymer main chain derived from a fluorine-containing ethylenic monomer (ml) having 2 or 3 carbon atoms and having at least one fluorine atom An acid-reactive group Y having a repeating unit (M 2) derived from a monomer (m2) which may contain a fluorine atom capable of giving an aliphatic ring structure, and reacting with an acid in the polymer Upon obtaining a fluoropolymer having ^one or acid-reactive group Y ¹ can be converted into a group Y ^2, fluorinated ethylenic monomer (ml) and / or polymer backbone into lipid aliphatic ring structure A process for producing a fluorine-containing polymer for resists having excellent vacuum ultraviolet light transparency, comprising radically polymerizing a monomer (m2) capable of giving a polymer by using a polymerization initiator having a fluorine atom.

 2. The repeating unit (M 1) derived from the above-mentioned fluorinated ethylenic monomer (ml) is tetrafluoroethylene, black trifluoroethylene, vinylidene fluoride, vinyl fluoride and hexafluoro. The production method according to claim 1, wherein the production unit is a structural unit derived from at least one monomer selected from propylene.

 3. The repeating unit (M2) derived from the monomer (m2) capable of giving an aliphatic ring structure to the polymer main chain is a repeating unit derived from a norpoleneene derivative which may contain a fluorine atom. Manufacturing method described in Paragraph 1 or 2.

4. The fluorinated ethylenic monomer (ml) and Z or the monomer (m2) capable of providing an aliphatic ring structure in the polymer main chain have an acid-reactive group Y ¹ or have an acid-reactive group the process according to any one of claims 1 through Section third term has a group convertible Y ² to a reactive group Y ^1.

5. If the fluoropolymer is a repeating unit other than the repeating units (Ml) and (M2) A unit returns Ri, Ri Repetitive derived from monomers having a Chikaratsu acid-reactive group Y ¹ can be converted to have or to the acid-reactive group Y ¹ having a group Y ² (nl) A repeating unit (N1), and in addition to the fluorine-containing ethylenic monomer (m1) and Z (or a monomer (m2) capable of giving an aliphatic ring structure to the polymer main chain), the acid reaction any of claims first to fourth terms of monomer the (nl) to radical polymerization have a group convertible Y ² or has a sexual group Y ¹ or an acid-reactive group Y 1 The production method described in Crab.

6. obtained by radical polymerization by a polymerization initiator having a fluorine atom, and acid-reactive groups fluoropolymer polymer reaction Obo acid-reactive group Y ¹ by having a group convertible Y ² to Y ¹ The manufacturing method according to claim 4 or 5, wherein the method is used to convert the method into a method.

7. The acid-reactive group Y ¹ in the fluorinated polymer is converted to a CO〇H group by dissociation with an OH group, an acid-dissociable functional group that can be converted to an OH group with an acid, a CO 0 H group, or an acid. The production method according to any one of claims 1 to 6, wherein the production method is at least one kind of acid dissociable functional group that can be used.

 8. The production method according to any one of claims 1 to 7, wherein the radical polymerization initiator having a fluorine atom is di (acyl) peroxide containing a fluorine atom.

 9. Di (a) yl peroxide has the formula:

O 0

 (Wherein m and n are the same or different and are integers from 1 to 20; X and X, are the same or different and are di (fluoroacyl) peroxides represented by F, C1 or H). The manufacturing method described in the item.

 10. The (a-sil) powder is the formula:

(CF ₃ CF ₂ CO〇) ₂ 10. The production method according to claim 9, wherein the production method is pennofluoropropionyl peroxide represented by the formula:

 11. The di (a-sil) peroxide has the formula:

(CF ₃ CF ₂ CF ₂ COO) ₂

 10. The production method according to claim 9, wherein the production method is hepnofluoride.

12. (A-1) At least an OH group, an acid-dissociable functional group that can be converted to an OH group with an acid, or an acid-dissociable functional group that can be dissociated with a COOH group or an acid to change to a C0H group. fluoropolymer having a one acid reactive groups Y ^1,

(B) a photoacid generator, and

 (C) Solvent

 Wherein the fluoropolymer (A-1) is a polymer obtained by the production method according to any one of claims 1 to 11. A photoresist composition that gives a resist film with excellent transparency.

13. The photoresist composition according to claim 12, wherein the fluoropolymer (A-1) is a polymer having an extinction coefficient at 157 nm wavelength of 1.0 xm "" ¹ or less.

 14. Equation (1):

 One (M1A)-(M2A)-(N1A) — (1)

(Wherein, Ml A is a structural unit derived from tetrafluoroethylene; M2A is a structural unit derived from a norpolenene derivative (m2a) which may contain a fluorine atom; N 1 A is tetrafluoroethylene and It is represented by a monomer (n1a) -derived structural unit copolymerizable with the norpolenene derivative (m2a). The structural unit M1A is 12 to 70 mol%, and the structural unit M2A is 12 to 7%. 0 mol%, containing 0 to 60 mol% of the structural unit Nl A, and (M1A) + ( (MIA) / (M2A) is a fluorinated polymer having a number average molecular weight of 1,000 to 50,000 at a ratio of 30/70 to 70/30 mol% when (M2A) = 100. At least one end of the polymer main chain contains a polymer molecule having a CF ₃ group, and the intensity of one CF ₃ signal at the end of the polymer main chain detected by ¹⁹ F-NMR analysis is H (terminal CF ₃ ), the main chain forming one CF ₂ —Signal intensity is defined as H (—CF ₂ —). Equation (1):

0.3 ≥ H (terminal CF ₃ ) / H (one CF ₂ —) ≥ 0.01 A fluoropolymer that satisfies the relational expression (1).