JP2006328241A - Resin for resist, and monomer for resist resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin for resists, which can provide resist compositions capable of reducing the standing waves of resist patterns, and to provide a monomer for resist resins. <P>SOLUTION: This resin for the resists is characterized by being a resin (A1) having structural units (a1) derived from hydroxystyrene, structural units (a2) each having an acid-dissociative dissolution-controlling group, and structural units (a3) represented by the general formula (a3-1) (R is H, an alkyl, a fluorine atom and a fluorinated alkyl; R<SP>1</SP>is H or an acid-dissociative dissolution-controlling group; A is a single bond or a divalent organic group; Ar is an arylene which may have one or more substituents). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resist resin and a resist resin monomer.

In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, miniaturization has rapidly progressed due to advances in lithography technology.
As a means for miniaturization, the wavelength of exposure light is generally shortened. Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but nowadays, KrF excimer laser (248 nm) has been introduced, and ArF excimer laser (193 nm) has begun to be introduced. In addition, studies have been conducted on shorter wavelength F ₂ excimer lasers (157 nm), EUV (extreme ultraviolet rays), electron beams, X-rays, and the like.

By the way, in order to reproduce a resist pattern having a fine dimension, a resist material having high resolution is required.
As such a resist material, a chemically amplified resist composition containing a base resin and an acid generator that generates an acid upon exposure is used.
For example, a positive chemically amplified resist contains a resin component whose alkali solubility is increased by the action of an acid and an acid generator component that generates an acid upon exposure. When acid is generated from the above, the exposed portion becomes alkali-soluble.
As a resin component of the chemically amplified positive resist composition, a resin in which a hydroxyl group of a polyhydroxystyrene (PHS) resin is protected with an acid dissociable, dissolution inhibiting group is generally used.
Examples of the acid dissociable, dissolution inhibiting group include so-called acetal acid dissociable, dissolution inhibiting groups such as a chain ether group represented by 1-ethoxyethyl group and a cyclic ether group represented by tetrahydropyranyl group; So-called annealing-based acid dissociable, dissolution inhibiting groups such as tertiary alkyl groups typified by tert-butyl groups and tertiary alkoxycarbonyl groups typified by tert-butoxycarbonyl groups are used (for example, Patent Document 1).

On the other hand, in the manufacture of semiconductor elements and liquid crystal display elements, an impurity diffusion layer is formed on the substrate surface.
The formation of the impurity diffusion layer is usually performed in two stages, impurity introduction and diffusion. As one of the introduction methods, impurities such as phosphorus and boron are ionized in vacuum and accelerated by a high electric field. There is ion implantation (hereinafter referred to as “implantation”) that is implanted into the substrate surface.
As a method for selectively implanting impurity ions on the substrate surface by implantation, for example, Patent Document 2 discloses a “gradient implantation” process in which implantation is performed in a state where the substrate on which a resist pattern (mask) is formed is inclined. It has been reported. This process is considered to be an effective means when ion implantation is desired only for a small part of the substrate that is directly under the resist pattern or the side wall of a hole formed in the substrate.
In the inclined implantation process, when a fine resist pattern of about 0.35 μm is formed, the resist pattern serving as a mask has a thickness of about 0.1 to 0.5 μm so that ion implantation is not hindered. A thin film is used.
Furthermore, the resist pattern in the inclined implantation process is required to have a shape characteristic for implanting ions into a desired portion of the substrate.

However, in such a tilt implantation process using a thin film resist pattern (hereinafter referred to as a thin film implantation process), particularly when a resin having high transparency with respect to exposure light is used, incident light during exposure is used. In addition, the resist pattern is likely to be defective due to the influence of reflected light from the substrate. This is called a standing wave (hereinafter abbreviated as SW). In particular, when a semiconductor element or a liquid crystal display element is manufactured, a thin film implantation process is performed on a substrate on which electrodes and the like are formed. Therefore, it is difficult to form a resist film with a uniform film thickness on the substrate. is there. Therefore, there is a problem of standing waves in which the resist pattern dimensions increase or decrease due to changes in the resist film thickness.
Thus, “SW” indicates a shape defect (a phenomenon in which the side wall of the resist pattern becomes wavy) due to the influence of reflected light on the resist pattern having a constant film thickness, and a dimension of the resist pattern due to a change in the resist film thickness. Sometimes refers to a phenomenon that increases or decreases.
The change in pattern dimension due to SW tends to increase as the resist film becomes thinner and the transparency of the resist film increases. Any of the above phenomena becomes a serious problem as the resist pattern becomes finer.
In order to solve such a problem, a compound (dye) having absorptivity to exposure light is mixed with a resist to suppress dimensional change (for example, see Patent Document 3).
JP 2002-341538 A JP-A-8-22965 JP 2003-149816 A

However, there is a limit to SW that can be reduced by blending the dye, and it is difficult to reduce SW, particularly in a thin film implantation process using a thin film.
This invention is made | formed in view of the said situation, and it aims at providing the resin for resist which can provide the resist composition which can reduce SW of a resist pattern, and the monomer for resist resin.

As a result of intensive studies, the present inventors have found that the above-described problems can be solved by using a resin having a specific structural unit having a functional group (SO ₂ ) that absorbs exposure light. Completed the invention.
That is, the first aspect of the present invention includes a structural unit (a1) derived from hydroxystyrene, a structural unit (a2) having an acid dissociable, dissolution inhibiting group, and the following general formula (a3-1)

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorine atom or a fluorinated alkyl group; R ¹ represents a hydrogen atom or an acid dissociable, dissolution inhibiting group; A represents a single bond or a divalent organic group; Ar represents an arylene group which may have a substituent. ]
It is resin (A1) which has structural unit (a3) represented by these, It is resin for resist characterized by the above-mentioned.
A second aspect of the present invention is the following general formula (a3-0)

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorine atom or a fluorinated alkyl group; R ¹ represents a hydrogen atom or an acid dissociable, dissolution inhibiting group; A represents a single bond or a divalent organic group; Ar represents an arylene group which may have a substituent. ]
It is the monomer for resist resins represented by these.

In the present specification and claims, the “structural unit” means a monomer unit (monomer unit) constituting a resin component (polymer compound).
The “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
“Exposure” is a concept including general irradiation of radiation.

  According to the present invention, it is possible to provide a resist resin and a resist resin monomer that can provide a resist composition that can reduce the standing wave of the resist pattern.

≪Resist resin≫
The resist resin of the present invention includes a structural unit (a1) derived from hydroxystyrene, a structural unit (a2) having an acid dissociable, dissolution inhibiting group, and a structural unit represented by the general formula (a3-1). It is resin (A1) which has (a3). The resin (A1) is preferably a copolymer.

・ Structural unit (a1)
The structural unit (a1) is a structural unit derived from hydroxystyrene.
In the structural unit (a1), the “structural unit derived from hydroxystyrene” includes a structural unit obtained by cleaving an ethylenic double bond of hydroxystyrene and a hydroxystyrene derivative (monomer).
Here, the “hydroxystyrene derivative” maintains at least a benzene ring and a hydroxyl group bonded thereto. For example, a hydrogen atom bonded to the α-position of hydroxystyrene is a halogen atom, a lower alkyl group having 1 to 5 carbon atoms. A group substituted with other substituents such as a group, a halogenated alkyl group, a benzene ring to which a hydroxyl group of hydroxystyrene is bonded, and a lower alkyl group having 1 to 5 carbon atoms further bonded, Those having 1 to 2 hydroxyl groups bonded to the bonded benzene ring (in this case, the total number of hydroxyl groups is 2 to 3) are included.
Examples of the halogen atom include a chlorine atom, a fluorine atom, and a bromine atom, and a fluorine atom is preferable.
The “α-position of hydroxystyrene” means a carbon atom to which a benzene ring is bonded unless otherwise specified.

  As what is contained in a structural unit (a1), the structural unit (a11) represented by the following general formula (a1-1) can be illustrated preferably.

［式中、Ｒは水素原子、アルキル基、フッ素原子またはフッ素化アルキル基を表し；Ｒ^２は炭素数１〜５の低級アルキル基を表し；ｐは１〜３の整数を表し；ｑは０または１〜２の整数を表す。］

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorine atom or a fluorinated alkyl group; R ² represents a lower alkyl group having 1 to 5 carbon atoms; p represents an integer of 1 to 3; Or the integer of 1-2 is represented. ]

The alkyl group of R is preferably a lower alkyl group, and is an alkyl group having 1 to 5 carbon atoms. Further, a linear or branched alkyl group is preferable, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. It is done. Of these, a methyl group is preferred industrially.
The fluorinated alkyl group is preferably a fluorinated lower alkyl group, in which part or all of the hydrogen atoms of the above-described lower alkyl group having 1 to 5 carbon atoms are substituted with fluorine atoms. In the present invention, it is preferable that all hydrogen atoms are fluorinated. The fluorinated lower alkyl group is preferably a linear or branched fluorinated lower alkyl group, more preferably a trifluoromethyl group, a hexafluoroethyl group, a heptafluoropropyl group, a nonafluorobutyl group, or the like. The group (—CF ₃ ) is most preferred.
R is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom.

Examples of the lower alkyl group having 1 to 5 carbon atoms of R ² include the same as the lower alkyl group of R.
q is 0 or an integer of 1-2. Among these, q is preferably 0 or 1, and particularly preferably 0 from an industrial viewpoint.
The substitution position of R ² may be any of o-position, m-position and p-position when q is 1, and when q is 2, any substitution position may be combined. it can.
p is an integer of 1 to 3, preferably 1.
The substitution position of the hydroxyl group may be any of the o-position, m-position and p-position when p is 1, but the p-position is preferred because it is readily available and inexpensive. Furthermore, when p is 2 or 3, arbitrary substitution positions can be combined.

As the structural unit (a1), one type or a mixture of two or more types can be used.
In the resin (A1), the proportion of the structural unit (a1) is preferably 20 to 80 mol% and more preferably 25 to 70 mol% with respect to all the structural units constituting the resin (A1). 30 to 65 mol% is more preferable, and 30 to 60 mol% is most preferable. Within this range, moderate alkali solubility can be obtained when the resist composition is prepared, and the balance with other structural units is good.

・ Structural unit (a2)
The structural unit (a2) is a structural unit having an acid dissociable, dissolution inhibiting group.
Preferred examples of the structural unit (a2) include the structural unit (a21) represented by the following general formula (a2-1) and the structural unit (a22) represented by the following general formula (a2-2). it can.

［式中、Ｒは水素原子、アルキル基、フッ素原子またはフッ素化アルキル基を表し；Ｒ^３は酸解離性溶解抑制基を表す。］

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorine atom or a fluorinated alkyl group; R ³ represents an acid dissociable, dissolution inhibiting group. ]

［式中、Ｒは水素原子、アルキル基、フッ素原子またはフッ素化アルキル基を表し；Ｒ^２は炭素数１〜５の低級アルキル基を表し；ｐは１〜３の整数を表し；ｑは０または１〜２の整数を表し；Ｒ^４は酸解離性溶解抑制基を表す。］

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorine atom or a fluorinated alkyl group; R ² represents a lower alkyl group having 1 to 5 carbon atoms; p represents an integer of 1 to 3; Or an integer of 1 to 2; R ⁴ represents an acid dissociable, dissolution inhibiting group. ]

In the general formulas (a2-1) and (a2-2), R ³ and R ⁴ each represent an acid dissociable, dissolution inhibiting group.
As the acid dissociable, dissolution inhibiting group, a resin for resist compositions such as for KrF excimer laser, ArF excimer laser, etc., can be appropriately selected from those proposed. For example, a chain tertiary alkoxycarbonyl group, a chain tertiary alkoxycarbonylalkyl group, or a chain or cyclic tertiary alkyl group can be preferably exemplified.

The chain tertiary alkoxycarbonyl group preferably has 4 to 10 carbon atoms, and more preferably 4 to 8 carbon atoms. Specific examples of the chain-like tertiary alkoxycarbonyl group include a tert-butoxycarbonyl group and a tert-amyloxycarbonyl group.
The chain tertiary alkoxycarbonylalkyl group preferably has 4 to 10 carbon atoms, and more preferably 4 to 8 carbon atoms. Specific examples of the chain-like tertiary alkoxycarbonylalkyl group include a tert-butoxycarbonylmethyl group, a tert-amyloxycarbonylmethyl group, and the like.
The chain-like tertiary alkyl group preferably has 4 to 10 carbon atoms, and more preferably 4 to 8 carbon atoms. Specific examples of the chain-like tertiary alkyl group include a tert-butyl group and a tert-amyl group.
The cyclic tertiary alkyl group is a monocyclic or polycyclic monovalent saturated hydrocarbon group containing a tertiary carbon atom on the ring. Specific examples of the cyclic tertiary alkyl group include 1-methylcyclopentyl group, 1-ethylcyclopentyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, 2-methyl-2-adamantyl group, 2-ethyl- A 2-adamantyl group and the like can be mentioned.

By including the chain tertiary alkoxycarbonyl group, the chain tertiary alkoxycarbonylalkyl group, the chain or cyclic tertiary alkyl group as the acid dissociable, dissolution inhibiting group, the heat resistance is improved.
Among these acid dissociable, dissolution inhibiting groups, a chain-like tertiary alkyl group is particularly preferable from the viewpoint of resolution, and among them, a tert-butyl group is more preferable.

  In the present invention, the following general formula (I) can be preferably exemplified as the acid dissociable, dissolution inhibiting group.

［式中、Ｘは脂肪族環式基、芳香族環式炭化水素基もしくは低級アルキル基を表し；Ｒ^５は水素原子もしくは低級アルキル基を表し、またはＸおよびＲ^５がそれぞれ独立に炭素数１〜５のアルキレン基であってＸの末端とＲ^５の末端とが結合していてもよく；Ｒ^６は水素原子もしくは低級アルキル基を表す。］

[Wherein, X represents an aliphatic cyclic group, an aromatic cyclic hydrocarbon group or a lower alkyl group; R ⁵ represents a hydrogen atom or a lower alkyl group, or X and R ⁵ each independently represent 1 carbon atom. An alkylene group of ˜5, and the end of X and the end of R ⁵ may be bonded; R ⁶ represents a hydrogen atom or a lower alkyl group; ]

Here, “aliphatic” in the present specification and claims is a relative concept with respect to aromatics, and is defined to mean groups, compounds, and the like that do not have aromaticity.
The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity and may be either saturated or unsaturated, but is usually preferably saturated.

The aliphatic cyclic group for X is a monovalent aliphatic cyclic group. The aliphatic cyclic group can be appropriately selected from those proposed in many conventional KrF resists and ArF resists.
Specific examples of the aliphatic cyclic group include an aliphatic monocyclic group having 5 to 7 carbon atoms and an aliphatic polycyclic group having 7 to 16 carbon atoms.
Examples of the aliphatic monocyclic group having 5 to 7 carbon atoms include groups in which one hydrogen atom has been removed from a monocycloalkane. Specifically, one hydrogen atom has been removed from cyclopentane, cyclohexane and the like. Group.
Examples of the aliphatic polycyclic group having 7 to 16 carbon atoms include groups in which one hydrogen atom has been removed from bicycloalkane, tricycloalkane, tetracycloalkane, etc., and specifically include adamantane, norbornane, isobornane. , Groups obtained by removing one hydrogen atom from polycycloalkanes such as tricyclodecane and tetracyclododecane. Among these, an adamantyl group, a norbornyl group, and a tetracyclododecanyl group are industrially preferable, and an adamantyl group is particularly preferable.

Examples of the aromatic cyclic hydrocarbon group for X include aromatic polycyclic groups having 10 to 16 carbon atoms. Specific examples include groups obtained by removing one hydrogen atom from naphthalene, anthracene, phenanthrene, pyrene and the like. More specifically, 1-naphthyl group, 2-naphthyl group, 1-anthracenyl group, 2-anthracenyl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 1-pyrenyl group and the like can be mentioned, In particular, a 2-naphthyl group is industrially preferable.
As the lower alkyl group for X, the same as the lower alkyl group for R in formula (a1-1) above can be mentioned.
X is preferably a lower alkyl group, more preferably a methyl group or an ethyl group, and most preferably an ethyl group.

Examples of the lower alkyl group for R ⁵ include the same as the lower alkyl group for R in the above formula (a1-1). Industrially, a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.
R ⁶ represents a lower alkyl group or a hydrogen atom. As the lower alkyl group for R ^{6, the same as} the lower alkyl group for R ⁵ can be exemplified. R ⁶ is preferably a hydrogen atom industrially.

In formula (I), X and R ⁵ are each independently an alkylene group having 1 to 5 carbon atoms, and the end of X and the end of R ⁵ may be bonded.
In this case, in Formula (I), a cyclic group is formed by R ⁵ , X, the oxygen atom to which X is bonded, and the carbon atom to which the oxygen atom and R ⁵ are bonded.
The cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

As the acid dissociable, dissolution inhibiting group (I), a group in which R ⁶ is a hydrogen atom is particularly preferable because of excellent effects of the present invention.
Specific examples thereof include, for example, a group in which X is an alkyl group, that is, a 1-alkoxyalkyl group, such as 1-methoxyethyl group, 1-ethoxyethyl group, 1-iso-propoxyethyl group, 1-n-butoxy. Examples include an ethyl group, 1-tert-butoxyethyl group, methoxymethyl group, ethoxymethyl group, iso-propoxymethyl group, n-butoxymethyl group, tert-butoxymethyl group and the like.
Examples of the group in which X is an aliphatic cyclic group include 1-cyclohexyloxyethyl group, (2-adamantyl) oxymethyl group, and 1- (1-adamantyl) oxyethyl represented by the following formula (II-a). Groups and the like.
Examples of the group in which X is an aromatic cyclic hydrocarbon group include a 1- (2-naphthyl) oxyethyl group represented by the following formula (II-b).
Among these, a 1-ethoxyethyl group is particularly preferable.

The acid dissociable, dissolution inhibiting group in the present invention comprises a chain tertiary alkoxycarbonyl group, a chain tertiary alkoxycarbonylalkyl group, a chain or cyclic tertiary alkyl group, and the above general formula (I). At least one selected from the group is preferably used.
Among them, those of the above general formula (I) are more preferable, and those of the above general formula (I) are most preferably contained as a main component.
Here, “containing as a main component” means 50 mol% or more of the acid dissociable, dissolution inhibiting groups contained in the resin (A1), preferably 70 mol% or more, More preferably means 80 mol% or more.

Examples of R in the structural units (a21) and (a22) include the same as R in the general formula (a1-1).
Examples of R ² in the structural unit (a22) include the same groups as R ^{2 in the} general formula (a1-1).
Examples of p and q in the structural unit (a22) are the same as p and q in the general formula (a1-1).

As the structural unit (a2), one type or a mixture of two or more types can be used.
In the resin (A1), the proportion of the structural unit (a2) is preferably from 5 to 70 mol%, more preferably from 5 to 65 mol%, based on all the structural units constituting the resin (A1). 5 to 60 mol% is more preferable, and 5 to 55 mol% is most preferable. By setting the lower limit value or more, a good resist pattern can be obtained when the resist composition is used, and by setting the upper limit value or less, the balance with other structural units is good.

Moreover, when the said structural unit (a2) is the said structural unit (a21), it is preferable that it is 5-70 mol% with respect to all the structural units which comprise resin (A1), and is 5-50 mol%. More preferably, it is more preferably 5 to 30 mol%, and most preferably 5 to 20 mol%. By setting the lower limit value or more, a good resist pattern can be obtained when the resist composition is used, and by setting the upper limit value or less, the balance with other structural units is good.
Moreover, when the said structural unit (a2) is the said structural unit (a22), it is preferable that it is 5-70 mol% with respect to all the structural units which comprise resin (A1), and is 10-65 mol%. More preferably, it is more preferably 20 to 60 mol%, and most preferably 30 to 55 mol%. By setting the lower limit value or more, a good resist pattern can be obtained when the resist composition is used, and by setting the upper limit value or less, the balance with other structural units is good.

・ Structural unit (a3)
The structural unit (a3) is a structural unit represented by the general formula (a3-1).
In formula (a3-1), A represents a single bond or a divalent organic group.
In the structural unit (a3), the “organic group” is a group containing a carbon atom, and an atom other than a carbon atom (for example, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom (fluorine atom, chlorine atom, etc.) Etc.).
As the organic group, a linear, branched or cyclic saturated hydrocarbon group is preferable, and a linear or branched saturated hydrocarbon group is more preferable. The saturated hydrocarbon group preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and still more preferably 1 to 6 carbon atoms.
The saturated hydrocarbon group may have a substituent. There is no restriction | limiting in particular as this substituent, For example, halogen atoms, such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned.
Here, “having a substituent” means that part or all of the hydrogen atoms of the saturated hydrocarbon group are substituted with a substituent.
Examples of the organic group also include a group in which a part of the carbon atoms of the saturated hydrocarbon group as described above is substituted with a heteroatom such as an oxygen atom, a nitrogen atom, or a sulfur atom.

As the organic group, a divalent saturated hydrocarbon group is particularly preferable.
As the saturated hydrocarbon group, an alkylene group is particularly preferable. The saturated hydrocarbon group may be linear, branched or cyclic.
Examples of the linear or branched alkylene group include a methylene group, an ethylene group, a propylene group, an isopropylene group, an n-butylene group, an isobutylene group, a tert-butylene group, a pentylene group, an isopentylene group, and a neopentylene group.
The cyclic alkylene group includes a cyclic group in which two hydrogen atoms are removed from a saturated hydrocarbon ring such as cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane, tetracyclododecane, etc., and linear to the cyclic group. Or the group etc. which the branched alkylene group couple | bonded are mentioned.
As the saturated hydrocarbon group, a linear or branched alkylene group is preferable, a linear alkylene group is more preferable, and an ethylene group or a propylene group is particularly preferable.
As A, a single bond is particularly preferable.

In formula (a3-1), Ar represents an arylene group which may have a substituent, and examples of the basic ring excluding the substituent include a phenylene group and a naphthylene group. Of these, a phenylene group is preferable.
Examples of the substituent include a linear or branched alkyl group having 1 to 4 carbon atoms. Among these, those having no substituent are preferable.
R may be the same as R in the general formula (a1-1).
As the acid dissociable, dissolution inhibiting group for R ¹ , a chain tertiary alkoxycarbonyl group, a chain tertiary alkoxycarbonylalkyl group, a chain or cyclic tertiary alkyl group exemplified for the structural unit (a2), In addition, at least one selected from the group consisting of the above general formula (I) is preferably used, and among these, preferred are the same as in the structural unit (a2).

As the structural unit (a3), one type or a mixture of two or more types can be used.
In the resin (A1), the proportion of the structural unit (a3) is preferably 1 to 30 mol%, more preferably 3 to 25 mol%, based on all the structural units constituting the resin (A1). 5 to 20 mol% is most preferable. By setting it within the above range, the standing wave suppressing effect is further improved.

・ Structural unit (a4)
The resin (A1) may further have a structural unit (a4) derived from styrene.
In the present invention, the structural unit (a4) is not essential, but when it is contained, the heat resistance can be improved when a resist composition is prepared.
In the structural unit (a4), the “structural unit derived from styrene” includes a structural unit obtained by cleaving an ethylenic double bond of styrene and a styrene derivative (not including hydroxystyrene). To do.
Here, the “styrene derivative” means that a hydrogen atom bonded to the α-position of styrene is substituted with another substituent such as a halogen atom, an alkyl group or an alkyl halide group, and a hydrogen atom of a phenyl group of styrene. Are those substituted by a substituent such as a lower alkyl group having 1 to 5 carbon atoms.
Examples of the halogen atom include a chlorine atom, a fluorine atom, and a bromine atom, and a fluorine atom is preferable.
The “α-position of styrene” means a carbon atom to which a benzene ring is bonded unless otherwise specified.

  As what is contained in a structural unit (a4), the structural unit (a41) represented by the following general formula (a4-1) can be illustrated preferably.

［式中、Ｒは水素原子、アルキル基、フッ素原子またはフッ素化アルキル基を表し；Ｒ^２は炭素数１〜５の低級アルキル基を表し；ｑは０または１〜２の整数を表す。］

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorine atom or a fluorinated alkyl group; R ² represents a lower alkyl group having 1 to 5 carbon atoms; q represents 0 or an integer of 1 to 2; ]

R and ^{R 2} include those similar to respectively R and ^{R 2} in the general formula (a1-1).
q is 0 or an integer of 1-2. Among these, q is preferably 0 or 1, and particularly preferably 0 from an industrial viewpoint.
The substitution position of R ² may be any of o-position, m-position and p-position when q is 1, and when q is 2, any substitution position can be combined.

As the structural unit (a4), one type or a mixture of two or more types can be used.
When resin (A1) contains a structural unit (a4), 1-25 mol% is preferable with respect to all the structural units which comprise resin (A1), and the ratio of a structural unit (a4) is 5-25 mol%. More preferably, it is most preferably 5 to 20 mol%. Within this range, when the resist composition is used, the heat resistance effect becomes high and the balance with other structural units is also good.

The resin (A1) may contain other structural units other than the above-described essential structural units (a1) to (a3) and the structural unit (a4) that is preferably included as long as the effects of the present invention are not impaired. .
Such a structural unit is not particularly limited as long as it is another structural unit that is not classified into the above-described essential structural units (a1) to (a3), preferably included structural units (a4). For KrF positive excimer lasers, As a resin used for resist such as ArF excimer laser, many conventionally known ones can be used.

However, for the effect of the present invention, the resin (A1) is preferably a resin containing the structural units (a1) to (a3) as main components.
Here, “main component” means that the total of the structural units (a1) to (a3) occupies 70 mol% or more of all the structural units constituting the resin (A1), preferably 80 mol%. As mentioned above, More preferably, it is 90 mol% or more. Most preferred is a resin composed of structural units (a1 to (a3)).

1000-100000 are preferable, as for the mass mean molecular weight (Mw; polystyrene conversion by gel permeation chromatography (GPC), the following is same)) of resin (A1), 5000-50000 are more preferable, and 7000-20000 are the most preferable.
When the mass average molecular weight is 100,000 or less, the resolution is high when a resist composition is formed, and it is particularly suitable for thin film implanters. On the other hand, when it is 1000 or more, the resist composition has high heat resistance and is particularly suitable for thin film implanters.
In other words, in the implantation process, the resist pattern on the substrate is heated by the heat generation action caused by the implantation of impurities, so that the resist pattern undergoes a shape change or a certain component in the resist pattern is gasified, resulting in the processing chamber. There is a possibility that the problem of lowering the degree of vacuum may occur, but due to its high heat resistance, it can be suitably used in such a process.
Further, the smaller the degree of dispersion (Mw / Mn (Mn: number average molecular weight)) of the resin (A1) (closer to monodispersion), the better the resolution and the better the resist composition. The dispersity is preferably 1.1 to 5.0, more preferably 1.1 to 3.0, and most preferably 1.1 to 2.5.

The resin (A1) can be obtained by polymerizing the monomer for deriving each structural unit by a conventional method, for example, a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN). .
Resin (A1) can be manufactured as follows, for example.
First, a precursor polymer of the resin (A1) is produced by known radical polymerization or the like, followed by elimination reaction of the protecting group of the precursor polymer, and in some cases, a protecting group that is eliminated by the action of an acid. It is introduced to obtain the resin (A1) of the present invention.

The production method of the precursor polymer is polymerized with a monomer in which the phenolic hydroxyl group of the monomer for deriving the structural unit (a1) is protected with an acetyl group, a monomer for deriving the structural unit (a2), and a monomer for deriving the structural unit (a3). The initiator is dissolved in an organic solvent, held at an appropriate temperature for an appropriate time, and then radical polymerization is performed.
As the organic solvent to be used, a solvent capable of dissolving any of the above monomers, polymerization initiators and the obtained polymer is preferable. For example, dioxane, isopropyl alcohol, acetone, tetrahydrofuran, 2-butanone, 4-methyl-2- Examples include pentanone.
Examples of the polymerization initiator used include azo compounds such as azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile), and organic peroxides such as benzoyl peroxide. .
The polymerization temperature is usually preferably in the range of 50 to 150 ° C., and the polymerization time is preferably 1 to 10 hours, more preferably about 2 hours or more. Outside the above range, problems such as low yield occur.
The precursor polymer solution thus obtained is poured into a large amount of poor solvent such as methanol, isopropyl alcohol, and water to be deposited. Thereafter, the precipitate is filtered and sufficiently dried to obtain a precursor polymer of the resin (A1) of the present invention.
In some cases, purification for removing unreacted monomers remaining in the precursor polymer, a polymerization initiator, or the like can be performed by an ordinary method such as a reprecipitation method.

In the method of carrying out the elimination reaction of the protecting group of the precursor polymer obtained by the above-mentioned method, the precursor polymer is dissolved in an organic solvent, an acidic compound and / or a basic compound is added, and an appropriate temperature is obtained at an appropriate temperature. Hold that temperature for hours.
The organic solvent used is preferably a solvent that can dissolve both the precursor polymer and the obtained resin (A1), and examples thereof include dioxane and tetrahydrofuran.
Examples of the acidic compound used include hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, and nitric acid, and hydrochloric acid is more preferably used.
Examples of the basic compound used include ammonia, hydrazine, caustic soda and the like, and hydrazine is more preferably used.
The amount of the acidic compound and / or basic compound used is usually 1.0 to 3.0 equivalents, preferably 1.0 to 1 with respect to the protective group for the phenolic hydroxyl group contained in the precursor polymer. .5 equivalents.
The temperature of the elimination reaction is usually preferably in the range of 10 to 50 ° C., and the reaction time is preferably 1 to 10 hours, more preferably about 2 hours or more.
The resin (A1) solution thus obtained is poured into a large amount of poor solvent such as water and precipitated. Thereafter, the precipitate is filtered and sufficiently dried to obtain the resin (A1) of the present invention.
In some cases, purification can be performed by a usual method such as a reprecipitation method.

Further, in some cases, when a protecting group that is eliminated by the action of an acid is introduced into the resin, a known method can be used depending on the type of the protecting group to be introduced, but when the protecting group is an α-alkoxyalkyl group. Is prepared by dissolving the resin obtained by the above method and a vinyl ether compound for inducing a protecting group in an organic solvent, adding an acidic compound, keeping the reaction at an appropriate temperature for an appropriate time, and reacting.
Examples of the organic solvent used include dioxane and tetrahydrofuran.
Examples of the acidic compound used include p-toluenesulfonic acid monohydrate, hydrochloric acid, sulfuric acid and the like.
The reaction temperature is usually preferably in the range of 0 to 50 ° C., and the reaction time is preferably 15 minutes to 10 hours. If the reaction is carried out outside the above range, the yield will be low.
The solution thus obtained is poured into an aqueous alkali solution or an aqueous solution for precipitation, and then the precipitate is filtered and dried to obtain a resin (A1).
In some cases, purification can be performed by a usual method such as a reprecipitation method.

≪Monomer for resist resin≫
The monomer for resist resin of the present invention is a monomer represented by the general formula (a3-0).
Wherein (a3-0), A, Ar and ^{R 1} are, A in formula (a3-1), include those similar respectively to Ar and ^{R 1.}

The method for producing a monomer for a resist resin of the present invention is a precursor obtained by reacting a compound represented by the following general formula (Z) with a compound that induces R ¹ of the monomer represented by the general formula (a3-0). And then reacting with an acid halide such as (meth) acrylic acid halide or α-fluoroacrylic acid halide that induces the structure represented by the general formula (a3-0). .

［式中、Ａ、Ａｒは、上記一般式（ａ３−１）のＡ、Ａｒとそれぞれ同様である。］

[Wherein, A and Ar are the same as A and Ar in the general formula (a3-1), respectively. ]

As a method for introducing the substituent R ¹ into the compound represented by the general formula (Z), a known method can be used depending on the structure of R ¹ , but when R ¹ is an α-alkoxyalkyl group, The compound represented by the general formula (Z) and the vinyl ether compound for inducing the substituent R ¹ are dissolved in an organic solvent, an acidic compound is added, and the mixture is held at an appropriate temperature for an appropriate time and reacted. To manufacture.
Examples of the organic solvent used include dioxane and tetrahydrofuran.
Examples of the acidic compound used include p-toluenesulfonic acid monohydrate, hydrochloric acid, sulfuric acid and the like.
The reaction temperature is usually preferably in the range of 0 to 50 ° C., and the reaction time is preferably 15 minutes to 10 hours. If the reaction is carried out outside the above range, the yield will be low.
The solution thus obtained is poured into an excess of aqueous caustic soda solution and precipitated. Thereafter, the precipitate is separated by filtration and further treated by a known method such as extraction or crystallization to obtain a monomer precursor that provides the structural unit (a3) of the present invention.

A method of reacting an acid halide with a monomer precursor is a (meth) acrylic acid halide in which a precursor and a basic compound are dissolved in an organic solvent to derive a structure represented by the general formula (a3-0), An acid halide such as α-fluoroacrylic acid halide is added, and the reaction is carried out by maintaining the reaction at an appropriate temperature for an appropriate time.
Examples of the organic solvent used include tetrahydrofuran, dioxane, acetone, 2-butanone and the like.
The basic compound used is preferably a tertiary organic amine such as triethylamine.
The reaction temperature is usually preferably in the range of 0 to 50 ° C., and the reaction time is preferably 15 minutes to 10 hours. If the reaction is carried out outside the above range, the yield will be low.
The solution thus obtained is poured into excess water and precipitated. Thereafter, the precipitate is filtered off and treated by a known method such as extraction or crystallization to obtain a monomer that provides the structural unit (a3) of the present invention.

≪Positive resist composition≫
As an example, the resist resin of the present invention has a resin component (A) (hereinafter referred to as (A) component) having an acid dissociable, dissolution inhibiting group and increased in alkali solubility by the action of an acid, and an acid upon exposure. It can be used for a positive resist composition containing an acid generator component (B) (hereinafter referred to as the component (B)) that generates a hydrogen, and is a resin contained in the component (A).

<(A) component>
In the positive resist composition, the component (A) includes the resin (A1) that is the resist resin of the present invention, and the following resins (A2) to (A4) other than the resin (A1) may be used in combination. Good.

・ Resin (A2)
The resin (A2) is a structural unit in which the acid dissociable, dissolution inhibiting group of the structural unit (a11) and the structural unit (a22) is substituted with the acid dissociable, dissolution inhibiting group represented by the general formula (I). And a resin component not containing the structural unit (a3).

Among all the structural units constituting the resin (A2), the structural unit (a11) is preferably 20 to 85 mol%, more preferably 30 to 80 mol%, and 45 to 80 mol%. Most preferred.
Of all the structural units constituting the resin (A2), the structural unit (a22) is preferably 5 to 60 mol%, more preferably 15 to 55 mol%, and more preferably 20 to 50 mol%. Most preferred.
In addition, when using other structural units, such as a structural unit (a4), it is preferable to set it as 10 mol% or less.

・ Resin (A3)
Resin (A3) is a structural unit in which the acid dissociable, dissolution inhibiting group of the structural unit (a11), (a22) is substituted with an acid dissociable, dissolution inhibiting group comprising a tertiary alkyloxycarbonyl group. A resin component that does not contain the structural unit (a3).
The tertiary alkyloxycarbonyl group is preferably a tertiary alkyloxycarbonyl group in which the tertiary alkyloxy group has 4 to 8 carbon atoms. Specific examples include a tert-butyloxycarbonyl group and a tert-amyl group. An oxycarbonyl group etc. are mentioned.

Among all the structural units constituting the resin (A3), the structural unit (a11) is preferably 20 to 85 mol%, more preferably 30 to 80 mol%, and 45 to 80 mol%. Most preferred.
Of all the structural units constituting the resin (A3), the structural unit (a22) is preferably 5 to 60 mol%, more preferably 10 to 50 mol%, and 15 to 45 mol%. Most preferred.
In addition, when using other structural units, such as a structural unit (a4), it is preferable to set it as 10 mol% or less.

・ Resin (A4)
The resin (A4) is a resin component having the structural unit (a11), the structural unit (a21), and the structural unit (a4), and not including the structural unit (a3). It is a resin component in which the acid dissociable, dissolution inhibiting group of the unit (a21) is substituted with an acid dissociable, dissolution inhibiting group composed of a tertiary alkyl group.
The tertiary alkyl group is preferably a tertiary alkyl group having 4 to 12 carbon atoms. Specific examples include a chain tertiary alkyl group such as a tert-butyl group and a tert-amyl group; 2 -Tertiary alkyl groups including polycyclic alicyclic hydrocarbon groups such as methyl-adamantyl group, 2-ethyladamantyl group; 1-ethylcyclohexyl, 1-ethylcyclopentyl group, 1-methylcyclohexyl group, 1 -Tertiary alkyl groups containing a monocyclic alicyclic hydrocarbon group such as methylcyclopentyl group. Among these, a chain tertiary alkyl group is more preferable.

Of all the structural units constituting the resin (A4), the structural unit (a11) is preferably 20 to 80% by mole, more preferably 30 to 75% by mole, and 45 to 75% by mole. Most preferred.
Of all the structural units constituting the resin (A4), the structural unit (a21) is preferably 5 to 60 mol%, more preferably 5 to 40 mol%, and 10 to 30 mol%. Most preferred.
Of all the structural units constituting the resin (A4), the structural unit (a4) is preferably 1 to 30 mol%, more preferably 5 to 30 mol%, and 5 to 20 mol%. Most preferred.

(A) As a ratio of the said resin (A1) in a component, 5-50 mass% is preferable, 10-40 mass% is more preferable, 15-40 mass% is the most preferable. By setting it to the lower limit value or more, reflected light from the substrate of exposure light is sufficiently absorbed, and the effect of reducing SW is improved. By setting it to the upper limit value or less, the absorption of exposure light is controlled and the resolution is improved.
(A) As a ratio of the said resin (A2) in a component, 5-80 mass% is preferable, 20-60 mass% is more preferable, 30-50 mass% is the most preferable.
(A) As a ratio of the said resin (A3) in a component, 5-80 mass% is preferable, 20-60 mass% is more preferable, 25-50 mass% is the most preferable.
(A) As a ratio of the said resin (A4) in a component, 5-80 mass% is preferable, 30-70 mass% is more preferable, 40-70 mass% is the most preferable.

  Among these, resin (A1), mixed resin of resin (A2) and resin (A3), or mixed resin of resin (A1) and resin (A4) improves lithography properties such as resolution. Therefore, it is preferable.

<(B) component>
The component (B) is not particularly limited, and those that have been proposed as acid generators for chemically amplified resists can be used.
Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, poly (bissulfonyl) diazomethanes, and the like. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.

  The onium salt-based acid generator may be referred to as an acid generator (B1) represented by the following general formula (B1) [hereinafter referred to as component (B1). ].

［式中、Ｒ^５１は、直鎖、分岐鎖もしくは環状のアルキル基、または直鎖、分岐鎖もしくは環状のフッ素化アルキル基を表し；Ｒ^５２は、水素原子、水酸基、ハロゲン原子、直鎖、分岐鎖もしくは環状のアルキル基、ハロゲン化アルキル基、またはアルコキシ基であり；Ｒ^５３は置換基を有していてもよいアリール基であり；ｎは１〜３の整数である。］

[Wherein R ⁵¹ represents a linear, branched or cyclic alkyl group, or a linear, branched or cyclic fluorinated alkyl group; R ⁵² represents a hydrogen atom, a hydroxyl group, a halogen atom, a linear group, A branched or cyclic alkyl group, a halogenated alkyl group, or an alkoxy group; R ⁵³ is an aryl group which may have a substituent; and n is an integer of 1 to 3. ]

In the general formula (B1), R ⁵¹ represents a linear, branched or cyclic alkyl group, or a linear, branched or cyclic fluorinated alkyl group.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group preferably has 4 to 12 carbon atoms, more preferably 5 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
The fluorinated alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The fluorination rate of the fluorinated alkyl group (ratio of fluorine atoms in the alkyl group) is preferably 10 to 100%, more preferably 50 to 100%. Particularly, all the hydrogen atoms are substituted with fluorine atoms. It is preferable because the strength of the acid is increased.
R ⁵¹ is most preferably a linear alkyl group or a fluorinated alkyl group.

R ⁵² represents a hydrogen atom, a hydroxyl group, a halogen atom, a linear, branched or cyclic alkyl group, a linear or branched halogenated alkyl group, or a linear or branched alkoxy group.
In R ⁵² , examples of the halogen atom include a fluorine atom, a bromine atom, a chlorine atom, and an iodine atom, and a fluorine atom is preferable.
In ^R52 , the alkyl group is linear or branched, and the number of carbon atoms thereof is preferably 1 to 5, particularly 1 to 4, and more preferably 1 to 3.
In R ⁵² , the halogenated alkyl group is a group in which part or all of the hydrogen atoms in the alkyl group are substituted with halogen atoms.
Examples of the alkyl group herein are the same as the “alkyl group” in R ⁵² . Examples of the halogen atom to be substituted include the same as those described above for the “halogen atom”.
In the halogenated alkyl group, 50 to 100% of the total number of hydrogen atoms are preferably substituted with halogen atoms, and more preferably all are substituted.
In R ⁵² , the alkoxy group is linear or branched, and the carbon number thereof is preferably 1 to 5, particularly 1 to 4, and more preferably 1 to 3.
Among these, R ⁵² is preferably a hydrogen atom.

R ⁵³ is an aryl group which may have a substituent, and examples of the basic ring structure excluding the substituent include a naphthyl group, a phenyl group, an anthracenyl group, and the like. From the viewpoint of absorption of exposure light such as, a phenyl group is preferable.
Examples of the substituent include a hydroxyl group and a lower alkyl group (straight chain or branched chain, preferably having 5 or less carbon atoms, particularly preferably a methyl group).
As the aryl group for R ^53, an aryl group having no substituent is more preferable.
n is an integer of 1 to 3, preferably 2 or 3, and particularly preferably 3.

  Preferable examples of the acid generator (B1) include the following.

  Among these, a compound represented by the following chemical formula (b-0-1) or (b-0-2) is preferable.

  Moreover, as an onium salt type | system | group acid generator, the compound represented by the following general formula (b-1) or (b-2) is also mentioned.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、アリール基またはアルキル基を表し；Ｒ^４”は、直鎖、分岐または環状のアルキル基またはフッ素化アルキル基を表し；Ｒ^１”〜Ｒ^３”の内、少なくとも１つはアリール基を表し；Ｒ^５”〜Ｒ^６”の内、少なくとも１つはアリール基を表す。］

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group; R ⁴ ″ represents a linear, branched or cyclic alkyl group or fluorinated group. Represents an alkyl group; at least one of R ¹ ″ to R ³ ″ represents an aryl group; at least one of R ⁵ ″ to R ⁶ ″ represents an aryl group.

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group. At least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably R ¹ ″ to R ³ ″ are all aryl groups.
The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups It may or may not be substituted with a group, a halogen atom or the like.
The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, ethyl group, propyl group, n-butyl group, or tert-butyl group. Is most preferred.
The alkoxy group that may be substituted for the hydrogen atom of the aryl group is preferably an alkoxy group having 1 to 5 carbon atoms, and most preferably a methoxy group or an ethoxy group.
The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.
The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, a straight, include alkyl groups such as branched or cyclic. Among these, from the viewpoint of excellent resolution, the number of carbon atoms is preferably 1 to 5. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decanyl group. . Among these, a methyl group is more preferable because it can be synthesized at a low cost.
Among these, it is most preferable that all of R ¹ ″ to R ³ ″ are phenyl groups.

R ⁴ ″ represents a linear, branched or cyclic alkyl group or a fluorinated alkyl group.
The linear alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group is a cyclic group as indicated by R ¹ ″ and preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and more preferably 6 carbon atoms. Most preferably, it is -10.
The fluorinated alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The fluorination rate of the fluorinated alkyl group (ratio of fluorine atoms in the alkyl group) is preferably 10 to 100%, more preferably 50 to 100%. Particularly, all the hydrogen atoms are substituted with fluorine atoms. It is preferable because the strength of the acid is increased.
R ⁴ ″ is most preferably a linear or cyclic alkyl group or a fluorinated alkyl group.

In formula (b-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group. At least one of R ⁵ ″ to R ⁶ ″ represents an aryl group. Of R ⁵ ″ to R ⁶ ″, two or more are preferably aryl groups, and most preferably all of R ⁵ ″ to R ⁶ ″ are aryl groups.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
Examples of the alkyl group for R ⁵ ″ to R ⁶ ″ include the same as the alkyl group for R ¹ ″ to R ³ ″.
Among these, it is most preferable that R ⁵ ″ to R ⁶ ″ are all phenyl groups.
"The, ^{R 4} in the formula (b-1)" ^{R 4} in the In the formula (b-2) include the same as.

Specific examples of the onium salt acid generator represented by the general formula (b-1) or (b-2) include diphenyliodonium trifluoromethanesulfonate, nonafluorobutanesulfonate, and bis (4-tert-butylphenyl). ) Iodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, triphenylsulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or nonafluorobutanesulfonate, tri (4-methylphenyl) sulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate Or its nonafluorobutanesulfonate, dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, Heptafluoropropane sulfonate or nonafluorobutane sulfonate thereof, monophenyldimethylsulfonium trifluoromethane sulfonate, heptafluoropropane sulfonate or nonafluorobutane sulfonate thereof, diphenylmonomethylsulfonium trifluoromethane sulfonate, heptafluoropropane sulfonate or nonafluoro thereof Butanesulfonate, trifluoromethanesulfonate of (4-methylphenyl) diphenylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of (4-methoxyphenyl) diphenylsulfonium, its heptafluoropropane sulfonate or its nonaflu Robutanesulfonate, trifluoromethanesulfonate of tri (4-tert-butyl) phenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenyl [1- (4-methoxy) naphthyl] sulfonium, its hepta Examples thereof include fluoropropane sulfonate and nonafluorobutane sulfonate thereof.
In addition, onium salts in which the anion portion of these onium salts is replaced with methanesulfonate, n-propanesulfonate, n-butanesulfonate, or n-octanesulfonate can also be used.

  Moreover, what replaced the anion part by the anion part represented by the following general formula (b-3) or (b-4) in the said general formula (b-1) or (b-2) can also be used. (The cation moiety is the same as (b-1) or (b-2)).

［式中、Ｘ”は、少なくとも１つの水素原子がフッ素原子で置換された炭素数２〜６のアルキレン基を表し；Ｙ”、Ｚ”は、それぞれ独立に、少なくとも１つの水素原子がフッ素原子で置換された炭素数１〜１０のアルキル基を表す。］

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms and substituted with

X ″ is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms. Most preferably, it has 3 carbon atoms.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, preferably It is C1-C7, More preferably, it is C1-C3.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, the strength of the acid increases as the number of hydrogen atoms substituted by fluorine atoms increases, and high-energy light and electrons of 200 nm or less This is preferable because the transparency to the line is improved.
The proportion of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all hydrogen atoms are substituted with fluorine atoms. A perfluoroalkylene group or a perfluoroalkyl group.

In the present invention, the oxime sulfonate-based acid generator is a compound having at least one group represented by the following general formula (B-1), and has a property of generating an acid upon irradiation with radiation. .
Such oxime sulfonate-based acid generators are frequently used for chemically amplified resist compositions, and can be arbitrarily selected and used.

［式（Ｂ−１）中、Ｒ^２１、Ｒ^２２はそれぞれ独立に有機基を表す。］

[In formula (B-1), R ²¹ and R ²² each independently represents an organic group. ]

In the present invention, an organic group is a group containing a carbon atom, and has an atom other than a carbon atom (for example, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom (a fluorine atom, a chlorine atom, etc.)). You may do it.
The organic group for R ²¹ is preferably a linear, branched or cyclic alkyl group or aryl group. These alkyl groups and aryl groups may have a substituent.
There is no restriction | limiting in particular as this substituent, For example, a fluorine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned.
Here, “having a substituent” means that part or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent.
As an alkyl group, C1-C20 is preferable, C1-C10 is more preferable, C1-C8 is more preferable, C1-C6 is especially preferable, and C1-C4 is the most preferable. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable.
The partially halogenated alkyl group means an alkyl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated alkyl group means that all of the hydrogen atoms are halogen atoms. Means an alkyl group substituted with
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.
The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms. As the aryl group, a partially or completely halogenated aryl group is particularly preferable.
The partially halogenated aryl group means an aryl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated aryl group means that all of the hydrogen atoms are halogen atoms. Means an aryl group substituted with.
R ²¹ is particularly preferably an alkyl group having 1 to 4 carbon atoms having no substituent or a fluorinated alkyl group having 1 to 4 carbon atoms.

As the organic group for R ²² , a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^22, the same alkyl groups and aryl groups as those described above for R ²¹ can be used.
R ²² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

  More preferable examples of the oxime sulfonate-based acid generator include compounds represented by the following general formula (B-2) or (B-3).

［式（Ｂ−２）中、Ｒ^３１は、シアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３２はアリール基である。Ｒ^３３は置換基を有さないアルキル基またはハロゲン化アルキル基である。］

[In Formula (B-2), R ³¹ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³² is an aryl group. R ³³ is an alkyl group having no substituent or a halogenated alkyl group. ]

［式（Ｂ−３）中、Ｒ^３４は、シアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３５は、２または３価の芳香族炭化水素基である。Ｒ^３６は、置換基を有さないアルキル基またはハロゲン化アルキル基である。ｐは、２または３である。］

[In Formula (B-3), R ³⁴ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁵ is a divalent or trivalent aromatic hydrocarbon group. R ³⁶ is an alkyl group having no substituent or a halogenated alkyl group. p is 2 or 3. ]

In the general formula (B-2), the alkyl group or halogenated alkyl group having no substituent for R ³¹ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably carbon atoms. Numbers 1 to 6 are most preferable.
R ³¹ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³¹ is preferably fluorinated by 50% or more of the hydrogen atom of the alkyl group, more preferably 70% or more, and even more preferably 90% or more.

As an aryl group of R ³² , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthracyl group, a phenanthryl group, or the like. And heteroaryl groups in which some of the carbon atoms constituting the ring of these groups are substituted with heteroatoms such as oxygen, sulfur, and nitrogen atoms. Among these, a fluorenyl group is preferable.
The aryl group represented by R ³² may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms.
The halogenated alkyl group is preferably a fluorinated alkyl group.

The alkyl group or halogenated alkyl group having no substituent for R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group, and most preferably a partially fluorinated alkyl group.
The fluorinated alkyl group in R ³³ preferably has 50% or more of the hydrogen atom of the alkyl group, more preferably 70% or more, and even more preferably 90% or more. This is preferable because the strength of the acid is increased. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

In the general formula (B-3), the alkyl group or halogenated alkyl group having no substituent for R ³⁴ is the same as the alkyl group or halogenated alkyl group having no substituent for R ^31. Is mentioned.
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁵ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³² .
Examples of the alkyl group or halogenated alkyl group having no substituent for R ³⁶ include the same alkyl groups or halogenated alkyl groups as those having no substituent for R ³³ .
p is preferably 2.

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Moreover, the compound represented by the following chemical formula is mentioned.

  Examples of preferred compounds among the compounds represented by formula (B-2) or (B-3) are shown below.

  Among the above exemplified compounds, the following three compounds are preferable.

Specific examples of bisalkyl or bisarylsulfonyldiazomethanes among diazomethane acid generators include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, Examples include bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane (when A = 3) and 1,4-bis (phenylsulfonyldiazo) having the following structure. Methylsulfonyl) butane (when A = 4), 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane (when A = 6), 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane (A = 10) 1), 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane (when B = 2), 1,3-bis (cyclohexylsulfonyldiazomethylsulfonyl) propane (when B = 3), 1,6- Bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane (when B = 6) (For B = 10) 1,10-bis (cyclohexyl diazomethylsulfonyl) decane and the like.

  Among these, a diazomethane acid generator is preferable because of excellent effects of the present invention.

(B) As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
The content of the component (B) in the positive resist composition containing the resist resin of the present invention is 0.5 to 30 parts by mass, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the component (A). The By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<Other optional components>
The positive resist composition containing the resist resin of the present invention further contains a nitrogen-containing organic compound (D) (hereinafter referred to as the (D) component) in order to improve the resist pattern shape, stability with time, and the like. Can be blended.
Since a wide variety of components (D) have already been proposed, any known one may be used. However, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines may be used. preferable.
Examples of the aliphatic amine include amines (alkyl amines or alkyl alcohol amines) in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms. Specific examples thereof include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di-n-heptylamine, Dialkylamines such as di-n-octylamine and dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine, tri-n-heptyl Trialkylamines such as amine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n -Ok Noruamin, alkyl alcohol amines such as tri -n- octanol amine. Among these, alkyl alcohol amines and trialkyl amines are preferable, and alkyl alcohol amines are most preferable. Of the alkyl alcohol amines, triethanolamine and triisopropanolamine are most preferred.
These may be used alone or in combination of two or more.
(D) component is normally used by 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

In the positive resist composition containing the resist resin of the present invention, as an optional component for the purpose of preventing sensitivity deterioration due to the blending of the component (D), and improving the resist pattern shape and the stability of holding. , An organic carboxylic acid or an oxo acid of phosphorus or a derivative thereof (E) (hereinafter referred to as component (E)). In addition, (D) component and (E) component can also be used together and any 1 type can also be used.
As the organic carboxylic acid, for example, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Phosphorus oxoacids or derivatives thereof include phosphoric acid, phosphoric acid di-n-butyl ester, phosphoric acid diphenyl ester and the like phosphoric acid or derivatives thereof such as phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid- Derivatives such as phosphonic acid and their esters such as di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester and phosphonic acid dibenzyl ester; phosphinic acids such as phosphinic acid and phenylphosphinic acid and their esters Among these, phosphonic acid is particularly preferable.
(E) A component is used by 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

The positive resist composition containing the resist resin of the present invention may contain a dissolution inhibitor (C) (hereinafter referred to as “component (C)”) as an optional component.
As the component (C), those proposed as dissolution inhibitors for chemically amplified resists can be used.
As the component (C), for example, a phenol derivative having a mass average molecular weight of 200 to 1,000 and having 1 to 6 substituted or unsubstituted benzene nuclei is preferable.
Specific examples thereof include compounds represented by the following general formula (C-1) or (C-2).

[前記Ｒ_Ｃは酸解離性溶解抑制基である。]

[The above R _C is an acid dissociable, dissolution inhibiting group. ]

[前記Ｒ_Ｃは酸解離性溶解抑制基である。]

[The above R _C is an acid dissociable, dissolution inhibiting group. ]

The acid dissociable, dissolution inhibiting group _RC can be arbitrarily selected from those known so far in chemically amplified positive resists.
Specifically, tertiary alkyloxycarbonyl groups such as tert-butyloxycarbonyl group and tert-amyloxycarbonyl group; tertiary groups such as tert-butyloxycarbonylmethyl group and tert-butyloxycarbonylethyl group Alkyloxycarbonylalkyl group; tertiary alkyl group such as tert-butyl group and tert-amyl group; cyclic ether group such as tetrahydropyranyl group and tetrahydrofuranyl group; alkoxyalkyl group such as ethoxyethyl group and methoxypropyl group It is mentioned as preferable.
Among these, tert-butyloxycarbonyl group, tert-butyloxycarbonylmethyl group, tert-butyl group, tetrahydropyranyl group, ethoxyethyl group, 1-methylcyclohexyl group and 1-ethylcyclohexyl group are more preferable.
The component (C) is used at 0.5 to 20 parts by mass with respect to 100 parts by mass of the component (A).

The positive resist composition containing the resist resin of the present invention can be produced by dissolving the material in an organic solvent.
The organic solvent is not particularly limited as long as it can dissolve each component to be used to form a uniform solution, and can be arbitrarily used from among conventionally known solvents for chemically amplified resists.
For example, lactones such as γ-butyrolactone, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, 2-heptanone, ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate , Polypropylenes such as dipropylene glycol or dipropylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof, cyclic ethers such as dioxane, methyl lactate , Ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate Methyl methoxypropionate, esters such as ethyl ethoxypropionate, and the like.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Moreover, the mixed solvent which mixed propylene glycol monomethyl ether acetate (PGMEA) and the polar solvent is preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, but is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to do.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2.
As the organic solvent, a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.
Although the amount of the organic solvent used is not particularly limited, it is a concentration that can be applied to a substrate and the like, and is appropriately set according to the coating film thickness. Generally, the solid content concentration of the resist composition is 2 to 20%. It is used so that it may become mass%, Preferably it is 5-15 mass%.

  The positive resist composition containing the resist resin of the present invention further contains miscible additives as desired, for example, additional resins for improving the performance of the resist film, and surfactants for improving the coatability. , Plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like can be added as appropriate.

As described above, the positive resist composition containing the resist resin of the present invention has a standing wave (SW), that is, a phenomenon in which the resist pattern dimension increases or decreases due to a change in the resist film thickness, and a resist pattern having a constant film thickness. The phenomenon that the side wall of the pattern becomes wavy due to the influence of the reflected light can be reduced. Among these, in a thin film with remarkable SW, a resist pattern with reduced SW can be formed, which is suitable for a thin film implantation process.
One of the reasons why such an effect is obtained is that, in the positive resist composition, by using the resist resin of the present invention having a structural unit having a functional group (SO ₂ ) that absorbs exposure light. This is considered to be because the reflected light from the substrate was sufficiently absorbed and the influence of the reflected light could be suppressed.
SW is caused by the influence of the reflected light from the substrate of the exposure light.
As described above, conventionally, in order to prevent this SW, a dye that absorbs reflected light from the substrate has been blended. However, the dye has insufficient absorption of reflected light from the substrate, and needs to be added in a large amount.
On the other hand, the dye has an inhibitory effect on dissolution in an alkaline developer, and if it is added in a large amount, problems such as scum generation occur, so there is a limit to the amount of dye added.
Moreover, the transmittance | permeability of an alkali developing solution falls by the dissolution inhibitory property to the alkali developing solution of dye. Therefore, the acid generation efficiency from the component (B) is deteriorated and the dissociation property of the acid dissociable, dissolution inhibiting group is lowered, so that it is presumed that the resist pattern cannot be sufficiently formed. Therefore, it is considered difficult to sufficiently reduce SW with a dye.
On the other hand, in the resist resin of the present invention, it is estimated that the reflected light from the substrate is sufficiently absorbed by the functional group (SO ₂ ) in the structural unit constituting the resin. Further, the resin does not have a problem of inhibition of dissolution in an alkaline developer such as a dye, and a resist pattern is sufficiently formed when a resist composition is formed. Therefore, it is thought that SW can be reduced in the positive resist composition containing the resist resin of the present invention.
In addition, since the dye is a low molecular compound, it tends to sublimate by heating, and there is a problem that the addition of the dye lowers the glass transition temperature of the resin component and lowers the heat resistance of the resist film.
In the positive resist composition containing the resist resin of the present invention, the amount of dye added can be reduced or not added, and therefore problems such as sublimation by heating and a decrease in glass transition temperature can be solved.

  SW is particularly prominent in the case of a thin film, and the positive resist composition containing the resist resin of the present invention can form a resist pattern with reduced SW in the thin film, so that it is suitable for a thin film implantation process. It is.

Furthermore, the positive resist composition containing the resist resin of the present invention is excellent in sensitivity and resolution. Also, the depth of focus is large. Furthermore, it is excellent in mask linearity, and a resist pattern faithful to the mask size can be reproduced when the mask size is changed.
Since the resist pattern used in the thin film implantation process is used as a mask for implanting impurity ions, as described above, the resist of the present invention can form a fine pattern with good reproducibility as well as small dimensional change. The positive resist composition containing the resin for coating is suitable for a thin film implantation process.

≪Resist pattern formation method≫
The method for forming a resist pattern of a positive resist composition containing the resist resin of the present invention comprises forming a resist film on a substrate using the positive resist composition, and subjecting the resist film to selective exposure treatment. Then, a development process is performed to form a resist pattern.
As an example, a resist pattern can be formed as follows.

First, a positive resist composition containing the resist resin of the present invention is applied onto a substrate such as a silicon wafer using a spinner or the like, and then prebaked at a temperature of 80 to 150 ° C. for 40 to 120 seconds, preferably 60 A resist film is formed by applying for 90 seconds.
Next, the resist film is selectively exposed through a desired mask pattern using an exposure apparatus, and then subjected to heat treatment (post-exposure baking (PEB)) at a temperature of 80 to 150 ° C. It is applied for 40 to 120 seconds, preferably 60 to 90 seconds.
Subsequently, after developing using an alkaline developer, for example, an aqueous solution of 1 to 10% by mass of tetramethylammonium hydroxide (TMAH), rinsing is performed, and the developer composition on the substrate and the resist composition dissolved by the developer The thing is washed away and dried to obtain a resist pattern.
The steps so far can be performed using a known method. The operating conditions and the like are preferably set as appropriate according to the composition and characteristics of the positive resist composition to be used.

If the film thickness of a resist film is 600 nm or less, it can be used suitably for a thin film implantation process, Preferably it is 100-550 nm, More preferably, it is 200-550 nm.
The radiation used for the exposure is not particularly limited, and is performed using ArF excimer laser, KrF excimer laser, F ₂ laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), electron beam, X-ray, soft X-ray, etc. Can do.
The positive resist composition containing the resist resin of the present invention is preferable for KrF excimer laser, electron beam or EUV (extreme ultraviolet), and particularly suitable for KrF excimer laser.
In some cases, the post-baking step after alkali development may be included.
Further, an organic or inorganic antireflection film may be provided between the substrate and the resist film or on the resist film.

  The resist pattern thus obtained can reduce SW even if it is a thin film of 550 nm or less, and is suitable for a thin film implantation process.

  Examples of the present invention will be described below, but the scope of the present invention is not limited to these examples. In addition, unless otherwise indicated, the part and% in an example are solid content except water, and show a mass part and the mass%, respectively.

In the following Example 1, resin (A) -1 represented by the following formula (1) and in Example 2, resin (A) -2 represented by the following formula (2) were used.
Note that “EE” in the formula represents a 1-ethoxyethyl group.

<Synthesis of Resins (A) -1 and (A) -2>
[Synthesis of Monomer (Monomer that provides Structural Unit (a3))]
A monomer that provides the structural unit (a3) contained in the resin component (A) of the present invention: 4- (4-tetrahydropyranoxyphenylsulfoxy) phenyl methacrylate was synthesized as follows.
(1) Precursor: Synthesis of 4- (4-tetrahydropyranoxyphenylsulfoxy) phenol A bis (4-hydroxyphenyl) sulfone was attached to a four-necked flask equipped with a nitrogen blowing tube, a reflux condenser, a dropping funnel and a thermometer. 62 g, 21,4-dihydro-2H-pyran 21 g, and dioxane 370 g were added and dissolved with stirring at about 20 ° C., and then a catalytic amount of p-toluenesulfonic acid monohydrate was added. Thereafter, stirring was continued at about 20 ° C. for 90 minutes.
The obtained reaction solution was added dropwise to a large amount of 1.4% NaOH aqueous solution, 100 g of toluene was added, and the mixture was stirred for 1 hour and allowed to stand. After confirming the separation, the upper layer (organic layer) was discarded, and 25 g of 36% hydrochloric acid was added while stirring the lower layer to obtain a precipitate. The precipitate was filtered and washed with water to obtain a white solid (precursor).
(2) Synthesis of 4- (4-tetrahydropyranoxyphenylsulfoxy) phenyl methacrylate A four-necked flask equipped with a stirrer, thermometer and dropping funnel, the precursor obtained in (1), 14 g of triethylamine, 290 g of acetone was added and dissolved by stirring. To the solution, 13 g of methacrylic acid chloride was slowly dropped at about 15 ° C., and stirring was continued at about 20 ° C. for 1 hour.
The obtained reaction solution was dropped into a large amount of water to obtain a precipitate. The precipitate was filtered, washed with water, and dried to obtain 42 g of a white solid (4- (4-tetrahydropyranoxyphenylsulfoxy) phenyl methacrylate).
(3) Identification of white solid obtained in (2) Isotope hydrogen nuclear magnetic resonance ¹ H-NMR (CDCl ₃ ) δ 1.54-2.03 (6H, m), 2.04 (3H, s) 3.60 (1H, m), 3.78 (1H, m), 5.49 (1H, t), 5.80 (1H, t), 6.35 (1H, t), 7.13 ( 2H, d), 7.25 (2H, d), 7.85 (2H, d), 7.95 (2H, d).

[Synthesis of resin]
Resin (A) -1
(1) Synthesis of precursor polymer 4-acetoxystyrene 0.5 g, styrene 0.1 g, t-butyl acrylate in a four-necked flask equipped with a stirrer, nitrogen inlet tube, reflux condenser, thermometer, and dropping device. 0.1 g, 4- (4-tetrahydropyranoxyphenylsulfoxy) phenyl methacrylate (0.3 g) and 2-butanone (72 g) were added, and the mixture was purged with nitrogen. While maintaining the temperature, 46.2 g of 4-acetoxystyrene, 8.1 g of styrene, 10.0 g of t-butyl acrylate, 31.3 g of 4- (4-tetrahydropyranoxyphenylsulfoxy) phenyl methacrylate, dimethyl 2, A solution prepared by dissolving 6.0 g of 2′-azobis (2-methylpropionate) in 72 g of 2-butanone was dropped from a dropping device at a constant rate over 3 hours. After completion of the dropping, stirring was continued for 5 hours while maintaining the temperature.
Then, it cooled to 20 degreeC and the obtained reaction solution was dripped at stirring in a large amount of isopropyl alcohol, and the deposit was obtained. The precipitate was filtered off to obtain a white solid precursor polymer.
(2) Synthesis of deprotected body The precursor polymer obtained in (1) was placed in a four-necked flask equipped with a stirrer, thermometer, and dropping funnel, and 96 g of tetrahydrofuran was added thereto and dissolved by stirring at 20 ° C. I let you. To the solution, 11 g of 36% hydrochloric acid was added dropwise, followed by stirring at 20 ° C. for 1 hour.
Thereafter, 36 g of 80% hydrazine monohydrate was added dropwise, followed by stirring at 20 ° C. for 1 hour. The obtained reaction solution was dropped into a large amount of water to obtain a precipitate. This precipitate was filtered, washed and dried to obtain 69 g of a white solid random copolymer.
(3) Identification of white solid obtained in (2) Mass average molecular weight (Mw) determined by gel permeation chromatography (GPC) in terms of polystyrene is 9,400, and dispersity (Mw / Mn) is 1.61. Met.
The copolymer composition ratio (molar ratio) determined by isotope carbon nuclear magnetic resonance ( ¹³ C-NMR) analysis was as follows: 4-hydroxystyrene part: styrene part: t-butyl acrylate part: 4- (4-hydroxyphenylsulfoxy) ) -Phenyl methacrylate part = 53: 17: 11: 18.

Resin (A) -2
(1) Synthesis of Precursor Polymer A 4-necked flask equipped with a nitrogen blowing tube, a reflux condenser, a dropping funnel and a thermometer was added to 201 g of 2-butanone, 1.9 g of 4-acetoxystyrene, and 4- (4-tetrahydropyranoxy). After adding 0.5 g of phenylsulfoxy) phenyl methacrylate and replacing with nitrogen, the temperature was raised to 82 ° C. with stirring. While maintaining the above temperature, 187 g of 4-acetoxystyrene, 52 g of 4- (4-tetrahydropyranoxyphenylsulfoxy) -phenyl methacrylate and 13 g of dimethyl 2,2′-azobis (2-methylpropionate) A solution dissolved in 161 g of butanone was added dropwise over 3 hours. After completion of the dropping, stirring was continued for 5 hours while maintaining the temperature.
The obtained reaction solution was dropped into a large amount of isopropyl alcohol to obtain a precipitate. This precipitate was filtered and washed to obtain a white solid (precursor polymer).
(2) Synthesis of deprotector The precursor polymer obtained in (1) and 241 g of tetrahydrofuran were placed in a four-necked flask equipped with a stirrer, a thermometer, and a dropping funnel, and stirred and dissolved at 50 ° C. To the solution, 35 g of 36% hydrochloric acid was added dropwise, stirred at 50 ° C. for 5 hours, and then cooled to 20 ° C. to complete the reaction.
The obtained reaction solution was dropped into a large amount of water to obtain a precipitate. This precipitate was filtered, washed and dried to obtain a white solid (deprotected body).
(3) Synthesis of Protective Body 115 g of the white solid (polymer) obtained in (2) and 575 g of tetrahydrofuran were placed in a four-necked flask equipped with a nitrogen blowing tube, a dropping funnel and a thermometer, and dissolved by stirring. 39 g of ethyl vinyl ether was added to the solution, and a catalyst amount of p-toluenesulfonic acid monohydrate was added at 20 ° C. with stirring. After stirring for 4 hours while maintaining the temperature, the reaction was stopped by adding triethylamine.
The obtained reaction solution was dropped into a large amount of water to obtain a precipitate. This precipitate was filtered, washed and dried to obtain 146 g of a white solid (protector).
(4) Identification of the white solid obtained in (3) / Mass average molecular weight (Mw) determined by polystyrene conversion by gel permeation chromatography (GPC) is 10,900, and dispersity (Mw / Mn) is 1. 86.
-The EE protection rate of the hydroxyl group of the 4-hydroxystyrene moiety and the EE protection of the hydroxyl group of the 4- (4-hydroxyphenylsulfoxy) -phenylmethacrylate moiety determined by isotope hydrogen nuclear magnetic resonance ( ¹ H-NMR) analysis The combined value of the rates was 50%.
The copolymer composition ratio (molar ratio) determined by isotope carbon nuclear magnetic resonance ( ¹³ C-NMR) analysis is as follows: 4-hydroxystyrene part: 4- (1-ethoxyethoxy) styrene part: 4- (4-hydroxy Phenylsulfoxy) -phenyl methacrylate part: 4- (4- (1-ethoxyethoxy) phenylsulfoxy) -phenyl methacrylate part = 40: 49: 3: 8.

<Preparation of positive resist composition solution>
A positive resist composition solution having the composition shown in Table 1 was prepared.
In addition, the numerical value in [] shows a compounding quantity (mass part).

  In the composition shown in Table 1, (A) component other than (A) -1 and (A) -2, (B) component, (C) component, (D) component, (E) component, organic solvent (S) The additive AD used was as follows.

(A) Component (A) -3: Hydroxystyrene / styrene / tert-butyl acrylate (molar ratio) = 70/15/15 (Mw = 12000, Mw / Mn = 2.1)
(A) -4: Resin in which 39 mol% of all hydroxyl groups of poly (p-hydroxystyrene) were protected with 1-ethoxyethyl group (Mw = 8000, Mw / Mn = 2.0)
(A) -5: Resin in which 39 mol% of all hydroxyl groups of poly (p-hydroxystyrene) were protected with a tert-butoxycarbonyl group (Mw = 8000, Mw / Mn = 1.1)

（Ｂ）−２：ビス（ｔｅｒｔ−ブチルフェニルヨードニウム）トリフルオロメタンスルホネート
（Ｂ）−３：ビス−Ｏ−（ｎ−ブチルスルホニル）−α−ジメチルグリオキシム
（Ｂ）−４：ビス（シクロヘキシルスルホニル）ジアゾメタン
（Ｂ）−５：ビス（ｔｅｒｔ−ブチルスルホニル）ジアゾメタン (B) Component (B) -1:

(B) -2: bis (tert-butylphenyliodonium) trifluoromethanesulfonate (B) -3: bis-O- (n-butylsulfonyl) -α-dimethylglyoxime (B) -4: bis (cyclohexylsulfonyl) Diazomethane (B) -5: Bis (tert-butylsulfonyl) diazomethane

（Ｃ）−２：

(C) Component (C) -1:

(C) -2:

(D) component:
(D) -1: Triethanolamine (D) -2: Triisopropanolamine

(E) Component (E) -1: Maleic acid (E) -2: Salicylic acid

ＡＤ３：界面活性剤 ＸＲ−１０４（商品名、大日本インキ化学工業社製） Additive AD
AD1: Dye Benzophenone AD2: Dye

AD3: Surfactant XR-104 (trade name, manufactured by Dainippon Ink & Chemicals, Inc.)

Organic solvent (S)
(S1): PGMEA / EL = 6/4 (mass ratio)

<Evaluation>
A resist pattern was formed using the positive resist composition solution obtained above, and standing wave (SW) evaluation was performed as follows.

(1) SW evaluation 1 in a resist pattern having a constant film thickness
(Example 1, Comparative Example 1, Comparative Example 3)
On the 8-inch silicon wafer, the positive resist composition solutions obtained in Example 1, Comparative Example 1, and Comparative Example 3 were uniformly applied using a spinner, and 100 ° C. for 60 seconds on a hot plate. By pre-baking and drying, a resist film having a film thickness of 250 nm was formed.
Next, using a KrF exposure apparatus (wavelength 248 nm) NSR-S203B (manufactured by Nikon, NA (numerical aperture) = 0.68, σ = 0.75), selective exposure was performed through a binary mask.
Then, PEB treatment was performed at 110 ° C. for 60 seconds, paddle development was further performed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, and then rinsed with pure water for 30 seconds, Shake off and dry.
Furthermore, it was heated at 110 ° C. for 60 seconds and dried to form 220 nm line and space (1: 1 and 1:10) resist patterns (hereinafter referred to as L / S patterns).

(Example 2, Comparative Example 2, Comparative Example 4)
On the 8-inch silicon wafer, the positive resist composition solutions obtained in Example 2, Comparative Example 2, and Comparative Example 4 were uniformly applied using a spinner, and 100 ° C. for 90 seconds on a hot plate. A resist film having a film thickness of 515 nm was formed by pre-baking and drying.
Next, using a KrF exposure apparatus (wavelength 248 nm) NSR-S203B (manufactured by Nikon, NA (numerical aperture) = 0.68, σ = 0.75), selective exposure was performed through a binary mask.
Then, PEB treatment is performed at 110 ° C. for 90 seconds, paddle development is further performed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, and then water rinsing is performed using pure water for 60 seconds. Shake off and dry.
Furthermore, it was heated at 100 ° C. for 60 seconds and dried to form 220 nm line and space (1: 1 and 1:10) resist patterns (hereinafter referred to as L / S patterns).

(SW evaluation 1)
The obtained resist pattern was visually evaluated according to the following criteria.
The evaluation results are shown in Table 2.
○: Standing wave was suppressed.
Δ: A standing wave was slightly generated.
X: A standing wave was generated.

(2) SW evaluation 2 in resist pattern when the film thickness is changed 2
Using the positive resist composition solutions obtained in Example 1, Comparative Example 1, and Comparative Example 3, resist films having film thicknesses of 175 nm, 190 nm, 210 nm, 230 nm, 240 nm, 250 nm, and 280 nm were formed, respectively, and the exposure dose An L / S pattern (1: 1) targeting 220 nm was formed under a constant condition, and the line width (pattern dimension (hereinafter referred to as CD)) of the formed resist pattern was measured.

(SW evaluation 2)
About obtained CD, the difference of largest CD and smallest CD was calculated | required as SW (nm). The obtained SW is shown in Table 3, and the obtained pattern dimension behavior (graph) is shown in FIG.

As is clear from the results in Table 2, in Examples 1 and 2, standing waves were suppressed.
From Table 3, it was confirmed that for SW, Example 1 had a smaller SW than that of Comparative Example 1, and the dimensional change with respect to the film thickness change was small. In Comparative Example 3 to which no dye was added, SW was remarkably large so that the evaluation at the same coordinate could not be performed.
As described above, according to the present invention, it was confirmed that a resist resin and a resist resin monomer capable of providing a resist composition capable of reducing the standing wave of the resist pattern can be provided.

FIG. 1A is a diagram showing a pattern dimension behavior with respect to a change in resist film thickness in Example 1, and FIG. 1B is a diagram showing a pattern dimension behavior with respect to a change in resist film thickness in Comparative Example 1.

Claims (11)

A structural unit (a1) derived from hydroxystyrene, a structural unit (a2) having an acid dissociable, dissolution inhibiting group, and the following general formula (a3-1)

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorine atom or a fluorinated alkyl group; R ¹ represents a hydrogen atom or an acid dissociable, dissolution inhibiting group; A represents a single bond or a divalent organic group; Ar represents an arylene group which may have a substituent. ]
Resin for resist which is resin (A1) which has structural unit (a3) represented by these. The structural unit (a1) is represented by the following general formula (a1-1)

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorine atom or a fluorinated alkyl group; R ² represents a lower alkyl group having 1 to 5 carbon atoms; p represents an integer of 1 to 3; Or the integer of 1-2 is represented. ]
The resist resin according to claim 1, comprising a structural unit (a11) represented by: The structural unit (a2) is represented by the following general formula (a2-1)

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorine atom or a fluorinated alkyl group; R ³ represents an acid dissociable, dissolution inhibiting group. ]
The resin for resists of Claim 1 or Claim 2 containing the structural unit (a21) represented by these. R ³ represents a chain tertiary alkoxycarbonyl group, a chain tertiary alkoxycarbonylalkyl group, a chain or cyclic tertiary alkyl group, and the following general formula (I)

[Wherein, X represents an aliphatic cyclic group, an aromatic cyclic hydrocarbon group or a lower alkyl group; R ⁵ represents a hydrogen atom or a lower alkyl group, or X and R ⁵ each independently represent 1 carbon atom. An alkylene group of ˜5, and the end of X and the end of R ⁵ may be bonded; R ⁶ represents a hydrogen atom or a lower alkyl group; ]
The resist resin according to claim 3, which is at least one acid dissociable, dissolution inhibiting group selected from the group consisting of: The structural unit (a2) is represented by the following general formula (a2-2)

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorine atom or a fluorinated alkyl group; R ² represents a lower alkyl group having 1 to 5 carbon atoms; p represents an integer of 1 to 3; Or an integer of 1 to 2; R ⁴ represents an acid dissociable, dissolution inhibiting group. ]
The resin for resists of Claim 1 or Claim 2 containing the structural unit (a22) represented by these. R ⁴ represents a chain tertiary alkoxycarbonyl group, a chain tertiary alkoxycarbonylalkyl group, a chain or cyclic tertiary alkyl group, and the following general formula (I)

[Wherein, X represents an aliphatic cyclic group, an aromatic cyclic hydrocarbon group or a lower alkyl group; R ⁵ represents a hydrogen atom or a lower alkyl group, or X and R ⁵ each independently represent 1 carbon atom. An alkylene group of ˜5, and the end of X and the end of R ⁵ may be bonded; R ⁶ represents a hydrogen atom or a lower alkyl group; ]
The resist resin according to claim 5, which is at least one acid dissociable, dissolution inhibiting group selected from the group consisting of:   Resin resin as described in any one of Claims 1-6 in which the said resin (A1) further has the structural unit (a4) induced | guided | derived from styrene. The structural unit (a4) is represented by the following general formula (a4-1)

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorine atom or a fluorinated alkyl group; R ² represents a lower alkyl group having 1 to 5 carbon atoms; q represents 0 or an integer of 1 to 2; ]
The resin for resists of Claim 7 containing the structural unit (a41) represented by these.   The resin for resist according to claim 1, wherein the resin (A1) has a mass average molecular weight (Mw) of 1000 to 100,000.   Resist resin for resists as described in any one of Claims 1-9 whose dispersity (Mw / Mn) of the said resin (A1) is 1.1-5.0. The following general formula (a3-0)

[Wherein, R represents a hydrogen atom, an alkyl group, a fluorine atom or a fluorinated alkyl group; R ¹ represents a hydrogen atom or an acid dissociable, dissolution inhibiting group; A represents a single bond or a divalent organic group; Ar represents an arylene group which may have a substituent. ]
A monomer for resist resin represented by

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