JP5358113B2 - Positive resist composition and pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a resist composition, restraining the occurrence of a defect in a resist pattern after development, especially fine scum and micro-bridge and having small line edge roughness, and to provide a resist composition and a pattern forming method using the same. <P>SOLUTION: There is provided the method for manufacturing a positive type resist composition containing (A) resin, which contains a specific repeating structural unit, and is dissolved by action of acid to increase solubility in an alkaline liquid developer, (B) compound, which generates acid by radiation of active light rays or radioactive rays, and (C) a solvent, which includes a filtering process, wherein the composition is passed through a filter having a nylon filtering film in the process. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a positive resist composition whose properties change upon reaction with irradiation of actinic rays or radiation, and a pattern forming method using the positive resist composition. More specifically, a positive resist composition used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, another photofabrication process, a lithographic printing plate, an acid curable composition, and the positive resist composition. The present invention relates to a pattern forming method using a mold resist composition.

  The chemically amplified positive resist composition is hardly soluble or insoluble in a developer immediately after film formation on a substrate, but generates an acid in an exposed portion by irradiation with radiation such as far ultraviolet light, and this acid is generated. It is a pattern forming material that improves the solubility of the active radiation irradiated portion in the developer by a reaction using a catalyst and forms a pattern on the substrate. In addition, the chemically amplified negative resist composition is readily soluble in a developer immediately after being formed on a substrate, but it generates an acid in an exposed portion by irradiation with radiation such as far ultraviolet light, and this acid is generated. This is a pattern forming material that reduces the solubility of the active radiation irradiated portion in the developer by a reaction using a catalyst and forms a pattern on the substrate.

  Chemically amplified resist compositions that use KrF excimer laser, ArF excimer laser, EUV (extreme ultraviolet light), EB (electron beam), etc. as a light source (radiation source) generally generate acid that generates acid upon exposure. An agent component and an organic solvent capable of dissolving these components are included. Such a chemically amplified resist composition is required to have a resist pattern having high resolution, high sensitivity, and a good shape.

When a further short wavelength light source such as an ArF excimer laser (193 nm) is used as an exposure light source, the compound having an aromatic group exhibits a large absorption in the 193 nm region, and thus the above chemical amplification system is not sufficient. It was.
Therefore, an ArF excimer laser resist containing a resin having an alicyclic hydrocarbon structure has been developed (for example, Patent Document 1: Japanese Patent Application Laid-Open No. 2005-97533, Patent Document 2: International Publication No. 05/016982). Pamphlet).
However, it has been difficult to satisfy various performances such as defocus latitude and pattern shape while maintaining sufficient transmittance.
Particularly in recent years, with the reduction of the pattern aiming at a line width of 45 nm or less, the thinning is progressing in order to suppress the pattern collapse. Since the etching process using a resist pattern as a mask is indispensable for device manufacturing, the process improvement to compensate for the lack of etching due to the thin film by the hard mask method is progressing, but the resistance to dry etching for pattern transfer to the hard mask is progressing. There is more demand.
JP 2005-97533 A International Publication No. 05/016982 Pamphlet

  The present invention has been made in view of the above circumstances, a resist composition having excellent exposure light transmittance, defocus latitude, pattern shape, excellent dry etching resistance, and less surface roughness after etching, and An object is to provide a pattern forming method using the same.

  As a result of intensive studies, the present inventors have found that the object of the present invention can be achieved by using a plurality of resins having a specific repeating unit, and have reached the present invention. That is, the above object is achieved by the following configuration.

[1]
Resin (A1) whose alkali solubility is increased by the reaction of an acid having a repeating unit represented by the following general formula (1) and a repeating unit represented by the general formula (2),
Resin (A2) whose alkali solubility is increased by the reaction of an acid having a repeating unit represented by the following general formula (3) and a repeating unit represented by the general formula (4), and
Compound (B) that generates acid upon irradiation with actinic ray or radiation,
Wherein the repeating unit represented by the general formula (4) does not contain a group that decomposes under the action of an acid, and further comprises a fluorine atom and a silicon atom. A positive resist composition comprising a hydrophobic resin having at least one of them.

In general formula (1),
Xa ₁ represents a hydrogen atom, a halogen atom, or an alkyl group.
T represents a single bond or a divalent linking group.
Rx _{1 to} Rx ₃ each independently represents an alkyl group or a cycloalkyl group.
At least two of Rx _{1 to} Rx ₃ may be bonded to form a cycloalkyl group.
In general formula (2),
Rb ₀ represents a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 4 carbon atoms.
Ab represents a single bond, an alkylene group, a divalent linking group having an alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these.
V represents a partial structure of any of the following LC1-3, LC1-4, LC1-7, LC1-8, LC1-9, and LC1-10.

Where
Rb ₂ represents an arbitrary substituent.
n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of Rb ₂ may be the same or different, or a plurality of Rb ₂ may be bonded to form a ring.
* Represents a bond to Ab in Formula (2), and represents that it can be bonded to Ab at any position even if the lactone ring is polycyclic.

In general formula (3),
Xa ₂ represents a hydrogen atom, a halogen atom or an alkyl group.
T ₂ represents a single bond or a divalent linking group.
Rx _{4 to} Rx ₆ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Rx _{4 to} Rx ₆ may combine to form a cycloalkyl group.
In general formula (4),
Rb ₁ represents a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 4 carbon atoms.
Ac represents a single bond, an alkylene group, a divalent linking group having an alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these.
W represents an alkyl group having 6 to 20 carbon atoms, an unsubstituted cycloalkyl group having 6 to 20 carbon atoms, or an aryl group.
[2]
The positive resist composition as described in [1], wherein the addition amount of the hydrophobic resin is 0.1 to 10% by mass based on the total solid content of the positive resist composition.
[3]
The positive resist composition as described in [1] or [2], wherein the hydrophobic resin has a group decomposable by the action of (z) acid.
[4]
The positive resist composition according to any one of [1] to [3], wherein the resin (A2) further has a repeating unit having a lactone structure.
[5]
The positive unit according to any one of [1] to [4], wherein the repeating unit represented by the general formula (1) is a repeating unit represented by the following general formula (I): Resist composition.

In general formula (I):
R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group.
R ² represents an alkyl group.
When there are a plurality of R ^{3 s} , each independently represents a halogen atom, an alkyl group, a cycloalkyl group, a cyano group or a hydroxyl group.
Z represents a cycloalkyl group having 3 to 8 carbon atoms.
n represents 0 or a positive integer.
[6]
The positive resist composition as described in [5], wherein the repeating unit represented by the general formula (I) is a repeating unit represented by the following general formula (II).

In the general formula (II), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group.
[7]
The positive resist composition according to any one of [1] to [6], further comprising a monoketone compound which may contain a ring as a solvent.
[8]
The positive resist composition as described in [7], wherein the monoketone compound which may contain a ring is cyclohexanone.
[9]
Any of [1] to [8], wherein the ratio of the resin (A1) to the resin (A2) is 90:10 to 30:70 by weight ratio of (A1) :( A2) 2. The positive resist composition according to item 1.
[10]
Any one of [1] to [9], wherein a ratio of the resin (A1) to the resin (A2) is 70:30 to 50:50 in a weight ratio of (A1) :( A2) 2. The positive resist composition according to item 1.
[11]
The positive resist composition according to any one of [1] to [10], wherein the resin (A1) and the resin (A2) do not have an aromatic group.
[12]
Any one of [1] to [11], wherein the resin (A1) and the resin (A2) are resins in which all of the repeating units are composed of (meth) acrylate repeating units. The positive resist composition as described.
[13]
In any one of [1] to [12], in the general formula (4), W is an alkyl group having 6 to 20 carbon atoms or an unsubstituted cycloalkyl group having 6 to 20 carbon atoms. The positive resist composition as described.
[14]
[1] A resist film formed of the positive resist composition according to any one of [13].
[15]
[14] A pattern forming method comprising exposing and developing the resist film according to [14].
[16]
The pattern forming method as described in [15], wherein the exposure is immersion exposure.
The present invention relates to the above [1] to [16], but other matters are also described.
1.
Resin (A1) whose alkali solubility is increased by the reaction of an acid having a repeating unit represented by the following general formula (1) and a repeating unit represented by the general formula (2),
Resin (A2) whose alkali solubility is increased by the reaction of an acid having a repeating unit represented by the following general formula (3) and a repeating unit represented by the general formula (4), and
Compound (B) that generates acid upon irradiation with actinic ray or radiation,
A positive resist composition comprising:

In general formula (1),
Xa ₁ represents a hydrogen atom, a halogen atom, or an alkyl group.
T represents a single bond or a divalent linking group.
Rx _{1 to} Rx ₃ each independently represents an alkyl group or a cycloalkyl group.
At least two of Rx _{1 to} Rx ₃ may be bonded to form a cycloalkyl group.
In general formula (2),
Rb ₀ represents a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 4 carbon atoms.
Ab represents a single bond, an alkylene group, a divalent linking group having an alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these.
V represents a partial structure of any of the following LC1-3, LC1-4, LC1-7, LC1-8, LC1-9, and LC1-10.

Where
Rb ₂ represents an arbitrary substituent.
n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of Rb ₂ may be the same or different, or a plurality of Rb ₂ may be bonded to form a ring.
* Represents a bond to Ab in Formula (2), and represents that it can be bonded to Ab at any position even if the lactone ring is polycyclic.

In general formula (3),
Xa ₂ represents a hydrogen atom, a halogen atom or an alkyl group.
T ₂ represents a single bond or a divalent linking group.
Rx _{4 to} Rx ₆ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Rx _{4 to} Rx ₆ may combine to form a cycloalkyl group.
In general formula (4),
Rb ₁ represents a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 4 carbon atoms.
Ac represents a single bond, an alkylene group, a divalent linking group having an alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these.
W represents an alkyl group having 6 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, or an aryl group.

2.
The positive resist composition as described in 1 above, wherein the resin (A2) further has a repeating unit having a lactone structure.

3.
(F) The positive resist composition according to 1 or 2 above, further comprising a hydrophobic resin.

4).
A pattern forming method comprising: forming a positive resist film using the resist composition of any one of 1 to 3 above; and exposing and developing the resist film.

  According to the present invention, a resist composition excellent in exposure light transmittance, defocus latitude, and pattern shape, and having little surface roughness (excellent in DE resistance) even when dry etching is performed at high speed, and a pattern using the same A forming method is provided.

Hereinafter, the components used in the present invention will be described in detail.
In addition, in the description of a group (atomic group) in this specification, the description which does not describe substitution and unsubstituted includes what has a substituent with what does not have a substituent. For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

(A) Resin whose solubility in an alkaline developer is increased by the action of an acid The positive resist composition of the present invention is
A resin (A1) whose alkali solubility is increased by the reaction of an acid having a repeating unit represented by the following general formula (1) and a repeating unit represented by the general formula (2);
A resin (A2) whose alkali solubility is increased by the reaction of an acid having a repeating unit represented by the following general formula (3) and a repeating unit represented by the following general formula (4);
Containing.

The positive resist composition of the present invention contains resins (A1) and (A2) whose solubility in an alkaline developer is increased by the action of an acid. Resins (A1) and (A2) are groups (hereinafter referred to as “acid-decomposable groups”) that decompose into the main chain or side chain of the resin, or both of the main chain and the side chain by the action of an acid to generate an alkali-soluble group. )).
Alkali-soluble groups include phenolic hydroxyl groups, carboxyl groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) (alkylcarbonyl) imides. Group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) methylene group, etc. Is mentioned.
Preferred alkali-soluble groups include carboxyl groups, fluorinated alcohol groups (preferably hexafluoroisopropanol), and sulfonic acid groups.
A preferable group as the acid-decomposable group is a group in which the hydrogen atom of these alkali-soluble groups is substituted with a group capable of leaving with an acid.
Examples of the group leaving with an acid include -C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), -C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), -C (R ₀₁ ) (R ₀₂ ). ) (OR ₃₉ ) and the like.
In the formula, R _{36 to} R ₃₉ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ may be bonded to each other to form a ring.
R _{01 and} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.
The acid-decomposable group is preferably a cumyl ester group, an enol ester group, an acetal ester group, a tertiary alkyl ester group or the like. More preferably, it is a tertiary alkyl ester group.

  The resin (A1) contains a repeating unit represented by the following general formula (1).

In general formula (1),
Xa ₁ represents a hydrogen atom, a halogen atom, or an alkyl group.
T represents a single bond or a divalent linking group.
Rx _{1 to} Rx ₃ each independently represents an alkyl group or a cycloalkyl group.
At least two of Rx _{1 to} Rx ₃ may be bonded to form a cycloalkyl group.

The alkyl group of Xa ₁ is preferably an alkyl group having 1 to 4 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Further, it may have a hydroxyl group, a halogen atom (more preferably a fluorine atom), a cyano group or the like. Xa ₁ is preferably a hydrogen atom or a methyl group.

Examples of the divalent linking group for T include an alkylene group, —COO—Rt— group, —O—Rt— group, and the like. In the formula, Rt represents an alkylene group or a cycloalkylene group.
T is preferably a single bond or a —COO—Rt— group. Rt is preferably an alkylene group having 1 to 5 carbon atoms, more preferably a —CH ₂ — group or a — (CH ₂ ) ₃ — group.

The alkyl group of Rx _{1 to} Rx ₃ is a linear or branched alkyl group having 1 carbon atom such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a t-butyl group. ~ 4 are preferred.
The cycloalkyl group of Rx _{1 to} Rx ₃ is a monocyclic or polycyclic cycloalkyl group, and is a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, a norbornyl group, a tetracyclodecanyl group, or a tetracyclododecanyl group. And a polycyclic cycloalkyl group such as an adamantyl group is preferred.
The cycloalkyl group formed by combining at least two of Rx _{1 to} Rx ₃ is a monocyclic or polycyclic cycloalkyl group, which is a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, a norbornyl group, a tetracyclo group. A polycyclic cycloalkyl group such as a decanyl group, a tetracyclododecanyl group or an adamantyl group is preferred.

Each group of Rx _{1 to} Rx ₃ and T may further have a substituent, and examples of the substituent that may be included include a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxy group, and a substituent. Carbonyl group, cycloalkyl group (preferably 3 to 10 carbon atoms), aryl group (preferably 6 to 14 carbon atoms), alkoxy group (preferably 1 to 10 carbon atoms), substituted acyl group (preferably 2 to 2 carbon atoms) 20), substituted acyloxy groups (preferably having 2 to 10 carbon atoms), substituted alkoxycarbonyl groups (preferably having 2 to 20 carbon atoms), substituted aminoacyl groups (preferably having 2 to 10 carbon atoms), and the like. Examples of the substituent of the cyclic structure in the aryl group, cycloalkyl group and the like include an alkyl group (preferably having 1 to 10 carbon atoms). Examples of the substituent in the substituted carbonyl group, substituted acyl group, substituted acyloxy group, and substituted alkoxycarbonyl group include 1 or 2 alkyl groups (preferably having 1 to 10 carbon atoms). Examples of the substituent in the substituted aminoacyl group include one or two alkyl groups (preferably having 1 to 10 carbon atoms).

As a combination of Rx _{1 to} Rx ₃ , the following embodiments are more preferable.
A mode in which Rx ₁ is a methyl group or an ethyl group (more preferably an ethyl group), and Rx ₂ and Rx ₃ are combined to form the above-described monocyclic cycloalkyl group (more preferably a cyclopentyl group).
A mode in which Rx ₁ and Rx ₂ are each a methyl group or an ethyl group (more preferably both methyl groups), and Rx ₃ forms the above-mentioned polycyclic cycloalkyl group (more preferably an adamantyl group).
A mode in which Rx ₁ and Rx ₂ are each a methyl group or an ethyl group (more preferably both methyl groups), and Rx ₃ is a monocyclic cycloalkyl group (more preferably a cyclohexyl group).

  Although the preferable specific example of the repeating unit represented by Formula (1) is shown below, this invention is not limited to this.

  The repeating unit represented by the formula (1) is more preferably a repeating unit represented by the following formula (I).

In general formula (I):
R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group.
R ² represents an alkyl group.
When there are a plurality of R ^{3 s} , each independently represents a halogen atom, an alkyl group, a cycloalkyl group, a cyano group or a hydroxyl group.
Z represents a cycloalkyl group having 3 to 8 carbon atoms.
n represents 0 or a positive integer.

As the alkyl group for R ¹ , an alkyl group having 1 to 4 carbon atoms is preferable, and examples thereof include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Further, it may have a hydroxyl group, a halogen atom (more preferably a fluorine atom), a cyano group or the like. R ¹ is preferably a hydrogen atom or a methyl group.
The alkyl group represented by R ² preferably has 1 to 3 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, and an isopropyl group.
Z is preferably a cycloalkyl group having 3 to 6 carbon atoms, more preferably a 5-membered ring, that is, a cyclopentane structure.

The halogen atom for R ₃ is preferably a fluorine atom.
Examples of the alkyl group for R ³ include a methyl group, an ethyl group, a propyl group, and an isopropyl group. The substituent of R ³ can be present at any position on the ring.
The cycloalkyl group represented by R ³ is preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, or a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group or an adamantyl group. .
n represents 0 or a positive integer. That is, the cycloalkyl group represented by Z may have a number that can substitute the substituent R ³ . n is preferably 0 or 1.

The alkyl group and cycloalkyl group in R ₂ and R ₃ may further have a substituent. Examples of the substituent which may be included include a halogen atom, a hydroxyl group, a nitro group, a cyano group, and a carboxy group. Group, substituted carbonyl group, cycloalkyl group (preferably 3 to 10 carbon atoms), aryl group (preferably 6 to 14 carbon atoms), alkoxy group (preferably 1 to 10 carbon atoms), substituted acyl group (preferably carbon Number 2-20), a substituted acyloxy group (preferably having 2 to 10 carbon atoms), a substituted alkoxycarbonyl group (preferably having 2 to 20 carbon atoms), a substituted aminoacyl group (preferably having 2 to 10 carbon atoms), and the like. Examples of the substituent of the cyclic structure in the aryl group, cycloalkyl group and the like include an alkyl group (preferably having 1 to 10 carbon atoms). Examples of the substituent in the substituted carbonyl group, substituted acyl group, substituted acyloxy group, and substituted alkoxycarbonyl group include 1 or 2 alkyl groups (preferably having 1 to 10 carbon atoms). Examples of the substituent in the substituted aminoacyl group include one or two alkyl groups (preferably having 1 to 10 carbon atoms).

  The repeating structural unit represented by the general formula (I) is particularly preferably a repeating structural unit represented by the general formula (II).

In the general formula (II), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group.

Specific examples of the repeating unit represented by the formula (I) are shown below, but are not particularly limited. In the formula, R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group.

  20-50 mol% is preferable with respect to all the repeating units in a polymer, and, as for the repeating unit represented by Formula (1), More preferably, it is 25-45 mol%.

  The resin (A1) further contains a repeating unit represented by the following general formula (2).

In general formula (2),
Rb ₀ represents a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 4 carbon atoms.
Ab represents a single bond, an alkylene group, a divalent linking group having an alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these.
V represents a partial structure of any of the following LC1-3, LC1-4, LC1-7, LC1-8, LC1-9, and LC1-10.

Where
Rb ₂ represents an arbitrary substituent.
n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of Rb ₂ may be the same or different, and a plurality of Rb ₂ may be bonded to form a ring.
* Represents a bond to Ab in Formula (2), and represents that it can be bonded to Ab at any position even if the lactone ring is polycyclic.

The alkyl group represented by Rb ₀ may have a substituent, and preferred substituents that may be included include a hydroxyl group and a halogen atom. Examples of the halogen atom for Rb ₀ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Rb ₀ is preferably a hydrogen atom or a methyl group.
It may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. More preferably, they are a C1-C4 alkyl group, a cyano group, and an acid-decomposable group.
n ₂ represents an integer of 0-4. When n ₂ is 2 or more, the plural substituents (Rb ₂ ) may be the same or different, and the plural substituents (Rb ₂ ) may be bonded to form a ring. .
Ab is preferably a single bond or a divalent linking group represented by —Ab ₁ —CO ₂ —. Ab ₁ is a linear, branched alkylene group, monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group or a norbornylene group.

  The repeating unit having a lactone group usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.

  Although the specific example of the repeating unit represented by Formula (2) is given below, this invention is not limited to these.

  Particularly preferred repeating units represented by the formula (2) include the following repeating units. By selecting an optimal lactone group, the pattern profile and the density dependence become good.

  As for the repeating unit represented by Formula (2), 15-60 mol% is preferable with respect to all the repeating units in a polymer, More preferably, it is 20-50 mol%, More preferably, it is 30-50 mol%.

  The resin (A2) is a resin whose alkali solubility is increased by the reaction of an acid having a repeating unit represented by the following general formula (3) and a repeating unit represented by the general formula (4).

In general formula (3),
Xa ₂ represents a hydrogen atom, a halogen atom or an alkyl group.
T ₂ represents a single bond or a divalent linking group.
Rx _{4 to} Rx ₆ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Rx _{4 to} Rx ₆ may combine to form a cycloalkyl group.
In general formula (4),
Rb ₁ represents a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 4 carbon atoms.
Ac represents a single bond, an alkylene group, a divalent linking group having an alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these.
W represents an alkyl group having 6 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, or an aryl group.

In the repeating unit represented by the general formula (3), Xa ₂ , T ₂ and Rx _{4 to} Rx ₆ represent the same as Xa ₁ , T and Rx _{1 to} Rx ₃ in the formula (1), respectively. The preferred examples are also the same.

  In the present invention, the general formula (3) in the resin (A2) preferably has the same structure as the repeating unit represented by the general formula (1) in the resin (A1). That is, the resins (A1) and (A2) of the present invention preferably have a repeating unit having the same structure, and the repeating unit is a structure represented by the general formula (1).

In addition, it is preferable that resin (A1) does not have a structure represented by General formula (4).
Moreover, it is preferable that the structure represented by General formula (4) does not contain the group decomposed | disassembled by the effect | action of an acid. Moreover, it is preferable not to contain an alkali-soluble group.
In the repeating unit represented by the general formula (4), those represented by Rb ₁ and Ac include those similar to Rb ₀ and Ab in the formula (2), respectively, and preferred examples are also the same.
The alkyl group having 6 to 20 carbon atoms of W may be linear or branched.
The cycloalkyl group having 6 to 20 carbon atoms of W is a monocyclic or polycyclic cycloalkyl group, a monocyclic cycloalkyl group such as a cyclohexyl group, a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, A polycyclic cycloalkyl group such as an adamantyl group, a spiroalkyl group such as a spirodecanyl group, and a bicycloalkyl group such as a bicyclo [4.4.0] decanyl group are preferable.
The aryl group for W is preferably a phenyl group or a naphthyl group.
Each substituent in W may further have a substituent, such as a hydroxyl group, a halogen atom, an alkyl group, or a cycloalkyl group.

  Specific examples of the repeating unit represented by the general formula (4) are listed below, but the present invention is not limited to these.

The resin (A2) preferably further has a repeating unit having a lactone group.
Any lactone group can be used as long as it has a lactone structure, but it is preferably a 5- to 7-membered ring lactone structure, and forms a bicyclo structure or a spiro structure in the 5- to 7-membered ring lactone structure. The other ring structure is preferably condensed. It is more preferable to have a repeating unit having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16). The lactone structure may be directly bonded to the main chain. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (LC1-14), and a specific lactone structure is used. This improves line edge roughness and development defects.

The lactone structure moiety may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. More preferably, they are a C1-C4 alkyl group, a cyano group, and an acid-decomposable group. n ₂ represents an integer of 0-4. When n ₂ is 2 or more, the plural substituents (Rb ₂ ) may be the same or different, and the plural substituents (Rb ₂ ) may be bonded to form a ring. .

  Examples of the repeating unit having a lactone structure represented by any one of the general formulas (LC1-1) to (LC1-16) include a repeating unit represented by the following general formula (AI).

In general formula (AI),
Rb ₀ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms. Preferred substituents that the alkyl group represented by Rb ₀ may have include a hydroxyl group and a halogen atom. Examples of the halogen atom for Rb ₀ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Rb ₀ is preferably a hydrogen atom or a methyl group.
Ab represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these. Preferably a single bond, -Ab ₁ -CO ₂ - is a divalent linking group represented by.
Ab ₁ is a linear, branched alkylene group, monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group or a norbornylene group.
V represents a group having a structure represented by any one of the general formulas (LC1-1) to (LC1-16).

  The repeating unit having a lactone group usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.

  The content of the repeating unit having a lactone group is preferably from 15 to 60 mol%, more preferably from 20 to 50 mol%, still more preferably from 30 to 50 mol%, based on all repeating units in the polymer.

  Specific examples of the repeating unit having a lactone group are listed below, but the present invention is not limited thereto.

  Particularly preferred repeating units having a lactone group include the following repeating units. By selecting an optimal lactone group, the pattern profile and the density dependence become good.

When resin (A2) contains the repeating unit which has a lactone structure, it is preferable that an almost repeating unit is a repeating unit represented by General formula (2) in resin (A1).
In this invention, when resin (A2) contains the repeating unit which has a lactone structure, it is more preferable that it is the same structure as the repeating unit represented by General formula (2) in resin (A1). That is, the resins (A1) and (A2) of the present invention preferably have a repeating unit having the same structure, and the repeating unit is a structure represented by the general formula (2).

  Resins (A1) and (A2) may further have a repeating unit having a hydroxyl group or a cyano group. This improves the substrate adhesion and developer compatibility. The repeating unit having a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group. The alicyclic hydrocarbon structure in the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably an adamantyl group, a diamantyl group, or a norbornane group. As the alicyclic hydrocarbon structure substituted with a preferred hydroxyl group or cyano group, partial structures represented by the following general formulas (VIIa) to (VIId) are preferred.

In general formulas (VIIa) to (VIIc),
R ₂ c to R ₄ c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R ₂ c to R ₄ c represents a hydroxyl group or a cyano group. Preferably, one or two of R ₂ c to R ₄ c are a hydroxyl group and the remaining is a hydrogen atom. In general formula (VIIa), more preferably, _two of R ₂ c to R ₄ c are hydroxyl groups and the remaining are hydrogen atoms.

  Examples of the repeating unit having a partial structure represented by the general formulas (VIIa) to (VIId) include the repeating units represented by the following general formulas (AIIa) to (AIId).

In the general formulas (AIIa) to (AIId),
R ₁ c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
R ₂ c to R ₄ c are in the general formula (VIIa) ~ (VIIc), same meanings as R ₂ c~R ₄ c.

  The content of the repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably 5 to 40 mol%, more preferably 5 to 30 mol%, still more preferably 10 with respect to all repeating units in the polymer. ˜25 mol%.

  Specific examples of the repeating unit having a hydroxyl group or a cyano group are given below, but the present invention is not limited thereto.

  The resins (A1) and (A2) can further have a repeating unit having an alkali-soluble group. Examples of the alkali-soluble group include a carboxyl group, a sulfonamide group, a sulfonylimide group, a bisulsulfonylimide group, and an aliphatic alcohol (for example, hexafluoroisopropanol group) substituted with an electron-attracting group at the α-position. It is more preferable to have a repeating unit. By containing the repeating unit having an alkali-soluble group, the resolution in contact hole applications is increased. The repeating unit having an alkali-soluble group includes a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or an alkali in the main chain of the resin through a linking group. Either a repeating unit to which a soluble group is bonded, or a polymerization initiator or chain transfer agent having an alkali-soluble group is used at the time of polymerization and introduced at the end of the polymer chain, and the linking group is monocyclic or polycyclic. It may have a cyclic hydrocarbon structure. Particularly preferred are repeating units of acrylic acid or methacrylic acid.

  As for content of the repeating unit which has an alkali-soluble group, 0-20 mol% is preferable with respect to all the repeating units in a polymer, More preferably, it is 3-15 mol%, More preferably, it is 5-10 mol%.

  Specific examples of the repeating unit having an alkali-soluble group are shown below, but the present invention is not limited thereto.

  As the repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group and an alkali-soluble group, more preferably, a repeating unit having at least two groups selected from a lactone group, a hydroxyl group, a cyano group and an alkali-soluble group Preferably, it is a repeating unit having a cyano group and a lactone group. Particularly preferred is a repeating unit having a structure in which a cyano group is substituted on the lactone structure of (LCI-4).

  Resins (A1) and (A2) may further have a repeating unit that has an alicyclic hydrocarbon structure and does not exhibit acid decomposability. This can reduce the elution of low molecular components from the resist film to the immersion liquid during immersion exposure. Examples of such a repeating unit include 1-adamantyl (meth) acrylate, diamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, and cyclohexyl (meth) acrylate repeating units.

  Resins (A1) and (A2) include, in addition to the above repeating structural units, dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general required characteristics of resist, resolving power, heat resistance, Various repeating structural units can be included for the purpose of adjusting sensitivity and the like.

  Examples of such repeating structural units include, but are not limited to, repeating structural units corresponding to the following monomers.

Thereby, the performance required for the resins (A1) and (A2), in particular,
(1) Solubility in coating solvent,
(2) Film formability (glass transition point),
(3) Alkali developability,
(4) Membrane slip (hydrophobic, alkali-soluble group selection),
(5) Adhesion of unexposed part to substrate,
(6) Dry etching resistance,
Etc. can be finely adjusted.

  As such a monomer, for example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. Etc.

  In addition, any addition-polymerizable unsaturated compound that can be copolymerized with monomers corresponding to the above various repeating structural units may be copolymerized.

  In the resins (A1) and (A2), the content molar ratio of each repeating structural unit is the resist dry etching resistance, the standard developer suitability, the substrate adhesion, the resist profile, and the resolving power, which is a general required performance of the resist, It is appropriately set for adjusting heat resistance, sensitivity, and the like.

  When the positive resist composition of the present invention is for ArF exposure, the resins (A1) and (A2) preferably have no aromatic group from the viewpoint of transparency to ArF light.

  The resins (A1) and (A2) are preferably those in which all of the repeating units are composed of (meth) acrylate repeating units. In this case, all of the repeating units are methacrylate repeating units, all of the repeating units are acrylate repeating units, or all of the repeating units are methacrylate repeating units and acrylate repeating units. Although it can be used, the acrylate-based repeating unit is preferably 50 mol% or less of the total repeating units. More preferably, the (meth) acrylate repeating unit having an acid-decomposable group is 20 to 50 mol%, the (meth) acrylate repeating unit having a lactone group is 20 to 50 mol%, and the alicyclic ring is substituted with a hydroxyl group or a cyano group. It is a copolymer containing 5 to 30 mol% of a (meth) acrylate-based repeating unit having a hydrocarbon structure and further 0 to 20 mol% of another (meth) acrylate-based repeating unit.

  When the positive resist composition of the present invention is irradiated with KrF excimer laser light, electron beam, X-ray, high-energy light beam (EUV, etc.) having a wavelength of 50 nm or less, the resins (A1) and (A2) It preferably has a hydroxystyrene-based repeating unit. More preferably, it has a hydroxystyrene-based repeating unit, a hydroxystyrene-based repeating unit protected with an acid-decomposable group, and an acid-decomposable repeating unit such as a (meth) acrylic acid tertiary alkyl ester.

  Preferred examples of the repeating unit having an acid-decomposable group include t-butoxycarbonyloxystyrene, 1-alkoxyethoxystyrene, a repeating unit of (meth) acrylic acid tertiary alkyl ester, and the like. The repeating unit by 2-adamantyl (meth) acrylate and dialkyl (1-adamantyl) methyl (meth) acrylate is more preferable.

Resins (A1) and (A2) can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as the solvent used in the positive resist composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.
The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.

The weight average molecular weights of the resins (A1) and (A2) are preferably 1,000 to 200,000, more preferably 2,000 to 20,000, and still more preferably 3 as a polystyrene conversion value by GPC method. 1,000 to 15,000, particularly preferably 3,000 to 10,000. By setting the weight average molecular weight to 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, developability is deteriorated, and viscosity is increased, resulting in deterioration of film forming property. Can be prevented.
The degree of dispersion (molecular weight distribution) is usually 1 to 3, preferably 1 to 2.6, more preferably 1 to 2, and particularly preferably 1.4 to 1.7. The smaller the molecular weight distribution, the better the resolution and the resist shape, and the smoother the side wall of the resist pattern, the better the roughness.

In the positive resist composition of the present invention, the total amount of the resin (A1) and (A2) in the entire composition is preferably 50 to 99.99% by mass, more preferably 60 to It is 99.0 mass%.
The ratio of the resin (A1) to the resin (A2) is preferably 90/10 to 30/70, more preferably 80/20 to 50/50, and still more preferably 70/70 by weight ratio of (A1) :( A2). 30-50 / 50.
In the present invention, the resins (A1) and (A2) may be used alone or in combination.

  Although the specific example of the repeating unit structure of resin (A1) is shown below, it is not limited to this.

  Although the specific example of the repeating unit structure of resin (A2) is shown below, it is not limited to this.

(B) Compound that generates acid upon irradiation with actinic ray or radiation The positive photosensitive composition of the present invention is a compound that generates acid upon irradiation with actinic ray or radiation (hereinafter also referred to as “acid generator”). contains.
As an acid generator, photo-initiator of photocation polymerization, photo-initiator of photo-radical polymerization, photo-decoloring agent of dyes, photo-discoloring agent, or irradiation with actinic ray or radiation used for micro resist Known compounds that generate acids and mixtures thereof can be appropriately selected and used.

  Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

  Further, a group that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, for example, US Pat. No. 3,849,137, German Patent No. 3914407. JP, 63-26653, JP, 55-164824, JP, 62-69263, JP, 63-146038, JP, 63-163452, JP, 62-153853, The compounds described in JP-A 63-146029 can be used.

  Furthermore, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712 and the like can also be used.

  Preferred compounds among the acid generators include compounds represented by the following general formulas (ZI), (ZII), and (ZIII).

In the general formula (ZI),
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1 to 30, preferably 1
~ 20.
Two of R _{201 to} R ₂₀₃ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).
Z ⁻ represents a non-nucleophilic anion.

Examples of the non-nucleophilic anion as Z ⁻ include a sulfonate anion, a carboxylate anion, a sulfonylimide anion, a bis (alkylsulfonyl) imide anion, and a tris (alkylsulfonyl) methyl anion.

  A non-nucleophilic anion is an anion that has an extremely low ability to cause a nucleophilic reaction and is an anion that can suppress degradation over time due to an intramolecular nucleophilic reaction. This improves the temporal stability of the resist.

  Examples of the sulfonate anion include an aliphatic sulfonate anion, an aromatic sulfonate anion, and a camphor sulfonate anion.

  Examples of the carboxylate anion include an aliphatic carboxylate anion, an aromatic carboxylate anion, and an aralkylcarboxylate anion.

  The aliphatic moiety in the aliphatic sulfonate anion may be an alkyl group or a cycloalkyl group, preferably an alkyl group having 1 to 30 carbon atoms and a cycloalkyl group having 3 to 30 carbon atoms such as methyl. Group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group , Tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, boronyl group and the like.

  The aromatic group in the aromatic sulfonate anion is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, and a naphthyl group.

  The alkyl group, cycloalkyl group and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion may have a substituent. Examples of the substituent of the alkyl group, cycloalkyl group, and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion include, for example, a nitro group, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), carboxyl group , Hydroxyl group, amino group, cyano group, alkoxy group (preferably having 1 to 15 carbon atoms), cycloalkyl group (preferably having 3 to 15 carbon atoms), aryl group (preferably having 6 to 14 carbon atoms), alkoxycarbonyl group ( Preferably 2 to 7 carbon atoms, acyl group (preferably 2 to 12 carbon atoms), alkoxycarbonyloxy group (preferably 2 to 7 carbon atoms), alkylthio group (preferably 1 to 15 carbon atoms), alkylsulfonyl group (Preferably having 1 to 15 carbon atoms), alkyliminosulfonyl group (preferably having 2 to 15 carbon atoms), aryl Ruoxysulfonyl group (preferably having 6 to 20 carbon atoms), alkylaryloxysulfonyl group (preferably having 7 to 20 carbon atoms), cycloalkylaryloxysulfonyl group (preferably having 10 to 20 carbon atoms), alkyloxyalkyloxy group (Preferably having 5 to 20 carbon atoms), a cycloalkylalkyloxyalkyloxy group (preferably having 8 to 20 carbon atoms), and the like. About the aryl group and ring structure which each group has, an alkyl group (preferably C1-C15) can further be mentioned as a substituent.

  Examples of the aliphatic moiety in the aliphatic carboxylate anion include the same alkyl group and cycloalkyl group as in the aliphatic sulfonate anion.

  Examples of the aromatic group in the aromatic carboxylate anion include the same aryl group as in the aromatic sulfonate anion.

  The aralkyl group in the aralkyl carboxylate anion is preferably an aralkyl group having 6 to 12 carbon atoms, such as a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, and a naphthylmethyl group.

  The alkyl group, cycloalkyl group, aryl group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion may have a substituent. Examples of the substituent of the alkyl group, cycloalkyl group, aryl group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion include, for example, the same halogen atom and alkyl as in the aromatic sulfonate anion Group, cycloalkyl group, alkoxy group, alkylthio group and the like.

  Examples of the sulfonylimide anion include saccharin anion.

  The alkyl group in the bis (alkylsulfonyl) imide anion and tris (alkylsulfonyl) methyl anion is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, An isobutyl group, a sec-butyl group, a pentyl group, a neopentyl group, and the like can be given. Examples of substituents for these alkyl groups include halogen atoms, alkyl groups substituted with halogen atoms, alkoxy groups, alkylthio groups, alkyloxysulfonyl groups, aryloxysulfonyl groups, cycloalkylaryloxysulfonyl groups, and the like. Alkyl groups substituted with fluorine atoms are preferred.

  Examples of other non-nucleophilic anions include fluorinated phosphorus, fluorinated boron, and fluorinated antimony.

Examples of the non-nucleophilic anion of Z ⁻ include an aliphatic sulfonate anion in which the α-position of the sulfonic acid is substituted with a fluorine atom, an aromatic sulfonate anion substituted with a fluorine atom or a group having a fluorine atom, and an alkyl group. A bis (alkylsulfonyl) imide anion substituted with a fluorine atom and a tris (alkylsulfonyl) methide anion wherein an alkyl group is substituted with a fluorine atom are preferred. The non-nucleophilic anion is more preferably a perfluoroaliphatic sulfonic acid anion having 4 to 8 carbon atoms, a benzenesulfonic acid anion having a fluorine atom, still more preferably a nonafluorobutanesulfonic acid anion, a perfluorooctanesulfonic acid anion, It is a pentafluorobenzenesulfonic acid anion and 3,5-bis (trifluoromethyl) benzenesulfonic acid anion.

Examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include the corresponding groups in the compounds (ZI-1), (ZI-2) and (ZI-3) described later.

In addition, the compound which has two or more structures represented by general formula (ZI) may be sufficient. For example, the general formula at least one of R ₂₀₁ to R ₂₀₃ of a compound represented by (ZI) is, at least one bond with structure of R ₂₀₁ to R ₂₀₃ of another compound represented by formula (ZI) It may be a compound.

  More preferable (ZI) components include compounds (ZI-1), (ZI-2), and (ZI-3) described below.

The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compounds, namely, compounds containing an arylsulfonium as a cation.

In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or a part of R _{201 to} R ₂₀₃ may be an aryl group with the remaining being an alkyl group or a cycloalkyl group.

  Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, and aryldicycloalkylsulfonium compounds.

  The aryl group of the arylsulfonium compound is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom or the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.

  The alkyl group or cycloalkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms and a cycloalkyl group having 3 to 15 carbon atoms, such as a methyl group, Examples thereof include an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

Aryl group, alkyl group of R ₂₀₁ to R _203, cycloalkyl group, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms) , An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group may be substituted. Preferred substituents are linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, more preferably carbon. An alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms. The substituent may be substituted with any one of the three R _{201 to} R ₂₀₃ , or may be substituted with all three. When R _{201 to} R ₂₀₃ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.

Next, the compound (ZI-2) will be described.
Compound (ZI-2) is a compound in which R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group having no aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.

The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear or branched 2-oxoalkyl group, 2-oxocycloalkyl group, alkoxy group. A carbonylmethyl group, particularly preferably a linear or branched 2-oxoalkyl group.

The alkyl group and cycloalkyl group of R ₂₀₁ to R _203, preferably a linear or branched alkyl group having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group), carbon Examples thereof include cycloalkyl groups of several 3 to 10 (cyclopentyl group, cyclohexyl group, norbornyl group). More preferred examples of the alkyl group include a 2-oxoalkyl group and an alkoxycarbonylmethyl group. More preferred examples of the cycloalkyl group include a 2-oxocycloalkyl group.

The 2-oxoalkyl group may be either linear or branched, and a group having> C = O at the 2-position of the above alkyl group is preferable.
The 2-oxocycloalkyl group is preferably a group having> C═O at the 2-position of the cycloalkyl group.

  The alkoxy group in the alkoxycarbonylmethyl group is preferably an alkoxy group having 1 to 5 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group).

R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

  The compound (ZI-3) is a compound represented by the following general formula (ZI-3), and is a compound having a phenacylsulfonium salt structure.

In general formula (ZI-3),
R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group or a halogen atom.
R _6c and R _7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
R _x and R _y each independently represents an alkyl group, a cycloalkyl group, an allyl group or a vinyl group.

Any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y may be bonded to each other to form a ring structure, and this ring structure includes an oxygen atom and a sulfur atom. , An ester bond and an amide bond may be included. Examples of the group formed by combining any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y include a butylene group and a pentylene group.

Zc ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as Z ^{− in} formula (ZI).

The alkyl group as R _{1c to} R _7c may be either linear or branched, for example, an alkyl group having 1 to 20 carbon atoms, preferably a linear or branched alkyl group having 1 to 12 carbon atoms ( Examples thereof include a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, and a linear or branched pentyl group. Examples of the cycloalkyl group include cyclohexane having 3 to 8 carbon atoms. An alkyl group (for example, a cyclopentyl group, a cyclohexyl group) can be mentioned.

The alkoxy group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).

Preferably, any of R _{1c to} R _5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group, and more preferably the sum of the carbon number of R _{1c to} R _5c. Is 2-15. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

_Examples of the alkyl group and cycloalkyl group as R _x and R _y include the same alkyl group and cycloalkyl group as in R _{1c to} R _7c , such as a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxy group. A carbonylmethyl group is more preferred.

Examples of the 2-oxoalkyl group and 2-oxocycloalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R _{1c to} R _7c .

Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as in R _{1c to} R _5c .

R _x and R _y are preferably an alkyl group or cycloalkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more alkyl groups or cycloalkyl groups.

In general formulas (ZII) and (ZIII),
R ₂₀₄ to R ₂₀₇ each independently represents an aryl group, an alkyl group or a cycloalkyl group.

Phenyl group and a naphthyl group are preferred as the aryl group of R ₂₀₄ to R _207, more preferably a phenyl group. Aryl group R ₂₀₄ to R ₂₀₇ represents an oxygen atom, a nitrogen atom, may be an aryl group having a heterocyclic structure having a sulfur atom and the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like.

The alkyl group and cycloalkyl group in R ₂₀₄ to R _207, preferably a linear or branched alkyl group having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group), carbon Examples thereof include cycloalkyl groups of several 3 to 10 (cyclopentyl group, cyclohexyl group, norbornyl group).

Aryl group, alkyl group of R ₂₀₄ to R _207, cycloalkyl groups may have a substituent. Aryl group, alkyl group of R ₂₀₄ to R _207, the cycloalkyl group substituent which may be possessed by, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms ), An aryl group (for example, having 6 to 15 carbon atoms), an alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthio group.

Z ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of Z ^{− in} formula (ZI).

  Examples of the acid generator further include compounds represented by the following general formulas (ZIV), (ZV), and (ZVI).

In general formulas (ZIV) to (ZVI),
Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₈ , R ₂₀₉ and R ₂₁₀ each independently represents an alkyl group, a cycloalkyl group or an aryl group.
A represents an alkylene group, an alkenylene group or an arylene group.

Among the acid generators, compounds represented by the general formulas (ZI) to (ZIII) are more preferable.
Further, the acid generator is preferably a compound that generates an acid having one sulfonic acid group or imide group, more preferably a compound that generates monovalent perfluoroalkanesulfonic acid, or a monovalent fluorine atom or fluorine atom. A compound that generates an aromatic sulfonic acid substituted with a group containing fluorinated acid, or a compound that generates a monovalent fluorine atom or imide acid substituted with a group containing a fluorine atom, and even more preferably, It is a sulfonium salt of a substituted alkanesulfonic acid, a fluorine-substituted benzenesulfonic acid, a fluorine-substituted imide acid or a fluorine-substituted methide acid. The acid generator that can be used is particularly preferably a fluorinated substituted alkane sulfonic acid, a fluorinated substituted benzene sulfonic acid or a fluorinated substituted imido acid whose pKa of the generated acid is pKa = -1 or less, and the sensitivity is improved. .

  Among acid generators, particularly preferred examples are given below.

An acid generator can be used individually by 1 type or in combination of 2 or more types.
The content of the acid generator in the positive resist composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, still more preferably, based on the total solid content of the positive resist composition. Is 1-7 mass%.

(C) Solvent Examples of the solvent that can be used when preparing the positive resist composition by dissolving the above components include, for example, alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate ester, Organic solvents such as alkyl alkoxypropionates, cyclic lactones (preferably having 4 to 10 carbon atoms), monoketone compounds that may contain rings (preferably having 4 to 10 carbon atoms), alkylene carbonates, alkyl alkoxyacetates, alkyl pyruvates, etc. Can be mentioned.

Examples of the alkylene glycol monoalkyl ether carboxylate include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl Preferred examples include ether propionate, ethylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate.
Preferred examples of the alkylene glycol monoalkyl ether include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether.

Preferred examples of the alkyl lactate include methyl lactate, ethyl lactate, propyl lactate and butyl lactate.
Preferable examples of the alkyl alkoxypropionate include ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate.

  Examples of the cyclic lactone include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, and γ-octano. Preferred are iclactone and α-hydroxy-γ-butyrolactone.

  Examples of the monoketone compound which may contain a ring include 2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3-methyl-2-pentanone, 4-methyl-2-pentanone, 2 -Methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5-hexen-2-one 3-penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, cyclohexanone, 3- Methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcycloheptanone, 3-methyl Preferred is cycloheptanone.

Preferred examples of the alkylene carbonate include propylene carbonate, vinylene carbonate, ethylene carbonate, and butylene carbonate.
Examples of the alkyl alkoxyacetate include 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2- (2-ethoxyethoxy) ethyl acetate, 3-methoxy-3-methylbutyl acetate, and 1-methoxy-acetate. 2-propyl is preferred.
Preferred examples of the alkyl pyruvate include methyl pyruvate, ethyl pyruvate, and propyl pyruvate.
As a solvent which can be preferably used, a solvent having a boiling point of 130 ° C. or higher under normal temperature and normal pressure can be mentioned. Specifically, cyclopentanone, γ-butyrolactone, cyclohexanone, ethyl lactate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate, ethyl pyruvate, 2-ethoxyethyl acetate, acetic acid -2- (2-ethoxyethoxy) ethyl and propylene carbonate are mentioned.
In the present invention, the above solvents may be used alone or in combination of two or more.

In this invention, you may use the mixed solvent which mixed the solvent which contains a hydroxyl group in a structure, and the solvent which does not contain a hydroxyl group as an organic solvent.
Examples of the solvent containing a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate, and the like. Particularly preferred are propylene glycol monomethyl ether and ethyl lactate.
Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are particularly preferred, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone is most preferred.
The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60/40. . A mixed solvent containing 50% by mass or more of a solvent not containing a hydroxyl group is particularly preferred from the viewpoint of coating uniformity.

  The solvent is preferably a mixed solvent of two or more containing propylene glycol monomethyl ether acetate.

(E) Basic compound The positive resist composition of the present invention preferably contains a basic compound in order to reduce the change in performance over time from exposure to heating.
Preferred examples of the basic compound include compounds having structures represented by the following formulas (A) to (E).

In general formulas (A) to (E),
R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different, and are a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (having a carbon number). 6-20), wherein R ²⁰¹ and R ²⁰² may combine with each other to form a ring.
About the said alkyl group, as an alkyl group which has a substituent, a C1-C20 aminoalkyl group, a C1-C20 hydroxyalkyl group, or a C1-C20 cyanoalkyl group is preferable.
R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms.
The alkyl groups in these general formulas (A) to (E) are more preferably unsubstituted.

  Preferred compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, piperidine and the like, and more preferred compounds include imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate Examples thereof include a compound having a structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, and an aniline derivative having a hydroxyl group and / or an ether bond.

  Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, benzimidazole, and 2-phenylbenzimidazole. Examples of the compound having a diazabicyclo structure include 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] non-5-ene, and 1,8-diazabicyclo [5,4,0. ] Undecar 7-ene etc. are mentioned. Examples of the compound having an onium hydroxide structure include tetrabutylammonium hydroxide, triarylsulfonium hydroxide, phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, specifically, triphenylsulfonium hydroxide, tris ( and t-butylphenyl) sulfonium hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, 2-oxopropylthiophenium hydroxide, and the like. As the compound having an onium carboxylate structure, an anion portion of the compound having an onium hydroxide structure is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate. Examples of the compound having a trialkylamine structure include tri (n-butyl) amine and tri (n-octyl) amine. Examples of the aniline compound include 2,6-diisopropylaniline, N, N-dimethylaniline, N, N-dibutylaniline, N, N-dihexylaniline and the like. Examples of the alkylamine derivative having a hydroxyl group and / or an ether bond include ethanolamine, diethanolamine, triethanolamine, N-phenyldiethanolamine, and tris (methoxyethoxyethyl) amine. Examples of aniline derivatives having a hydroxyl group and / or an ether bond include N, N-bis (hydroxyethyl) aniline.

Preferred examples of the basic compound further include an amine compound having a phenoxy group, an ammonium salt compound having a phenoxy group, an amine compound having a sulfonic acid ester group, and an ammonium salt compound having a sulfonic acid ester group.
As the amine compound, a primary, secondary or tertiary amine compound can be used, and an amine compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. The amine compound is more preferably a tertiary amine compound. As long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, the amine compound has an cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (preferably having 3 to 20 carbon atoms). Preferably C6-C12) may be bonded to a nitrogen atom. The amine compound preferably has an oxygen atom in the alkyl chain and an oxyalkylene group is formed. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

As the ammonium salt compound, a primary, secondary, tertiary, or quaternary ammonium salt compound can be used, and an ammonium salt compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. As long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, the ammonium salt compound has a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group in addition to the alkyl group. (Preferably having 6 to 12 carbon atoms) may be bonded to a nitrogen atom. The ammonium salt compound preferably has an oxygen atom in the alkyl chain and an oxyalkylene group is formed. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.
Examples of the anion of the ammonium salt compound include halogen atoms, sulfonates, borates, and phosphates. Among them, halogen atoms and sulfonates are preferable. As the halogen atom, chloride, bromide, and iodide are particularly preferable. As the sulfonate, an organic sulfonate having 1 to 20 carbon atoms is particularly preferable. Examples of the organic sulfonate include alkyl sulfonates having 1 to 20 carbon atoms and aryl sulfonates. The alkyl group of the alkyl sulfonate may have a substituent, and examples of the substituent include fluorine, chlorine, bromine, alkoxy groups, acyl groups, and aryl groups. Specific examples of the alkyl sulfonate include methane sulfonate, ethane sulfonate, butane sulfonate, hexane sulfonate, octane sulfonate, benzyl sulfonate, trifluoromethane sulfonate, pentafluoroethane sulfonate, and nonafluorobutane sulfonate. Examples of the aryl group of the aryl sulfonate include a benzene ring, a naphthalene ring, and an anthracene ring. The benzene ring, naphthalene ring and anthracene ring may have a substituent, and the substituent is preferably a linear or branched alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms. Specific examples of the linear or branched alkyl group and cycloalkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, t-butyl, n-hexyl, cyclohexyl and the like. Examples of the other substituent include an alkoxy group having 1 to 6 carbon atoms, a halogen atom, cyano, nitro, an acyl group, and an acyloxy group.

The amine compound having a phenoxy group and the ammonium salt compound having a phenoxy group are those having a phenoxy group at the terminal opposite to the nitrogen atom of the alkyl group of the amine compound or ammonium salt compound. The phenoxy group may have a substituent. Examples of the substituent of the phenoxy group include an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group, a sulfonic acid ester group, an aryl group, an aralkyl group, an acyloxy group, and an aryloxy group. Etc. The substitution position of the substituent may be any of the 2-6 positions. The number of substituents may be any in the range of 1 to 5.
It is preferable to have at least one oxyalkylene group between the phenoxy group and the nitrogen atom. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

In the amine compound having a sulfonic acid ester group and the ammonium salt compound having a sulfonic acid ester group, the sulfonic acid ester group may be any of alkyl sulfonic acid ester, cycloalkyl group sulfonic acid ester, and aryl sulfonic acid ester. In the case of an alkyl sulfonate ester, the alkyl group has 1 to 20 carbon atoms, in the case of a cycloalkyl sulfonate ester, the cycloalkyl group has 3 to 20 carbon atoms, and in the case of an aryl sulfonate ester, the aryl group has 6 carbon atoms. ~ 12 are preferred. Alkyl sulfonic acid ester, cycloalkyl sulfonic acid ester, and aryl sulfonic acid ester may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid. An ester group is preferred.
It is preferable to have at least one oxyalkylene group between the sulfonate group and the nitrogen atom. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

  These basic compounds are used alone or in combination of two or more.

  The usage-amount of a basic compound is 0.001-10 mass% normally on the basis of solid content of a positive resist composition, Preferably it is 0.01-5 mass%.

  The use ratio of the acid generator and the basic compound in the composition is preferably acid generator / basic compound (molar ratio) = 2.5 to 300. In other words, the molar ratio is preferably 2.5 or more from the viewpoint of sensitivity and resolution, and is preferably 300 or less from the viewpoint of suppressing the reduction in resolution due to the thickening of the resist pattern over time until post-exposure heat treatment. The acid generator / basic compound (molar ratio) is more preferably 5.0 to 200, still more preferably 7.0 to 150.

(D) Surfactant The positive resist composition of the present invention preferably further contains a surfactant, and a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based surfactant, It is more preferable to contain either one or two or more surfactants having both fluorine atoms and silicon atoms.

When the positive resist composition of the present invention contains the above-described surfactant, a resist pattern with good adhesion and low development defects can be obtained with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. It becomes possible.
Examples of the fluorine-based and / or silicon-based surfactant include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 5,824,451 Surfactant can be mentioned, The following commercially available surfactant can also be used as it is.
Examples of commercially available surfactants that can be used include EFTOP EF301 and EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 and 4430 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176 and F189. , F113, F110, F177, F120, R08 (manufactured by Dainippon Ink & Chemicals, Inc.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (manufactured by Asahi Glass Co., Ltd.), Troisol S-366 (Manufactured by Troy Chemical Co., Ltd.), GF-300, GF-150 (manufactured by Toa Gosei Chemical Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), F-top EF121, EF122A, EF122B, RF122C, EF125M , EF135M, EF351, 352, EF801, EF802, EF 01 (manufactured by Gemco), PF636, PF656, PF6320, PF6520 (manufactured by OMNOVA), FTX-204G, 208G, 218G, 230G, 204D, 208D, 212D, 218D, 222D (manufactured by Neos) Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.
As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. Or may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block link) or poly (block link of oxyethylene and oxypropylene) may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).

Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₃ F ₇ group and (poly (oxy) And a copolymer of (ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate).

  In the present invention, other surfactants other than fluorine-based and / or silicon-based surfactants can also be used. Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, etc. Sorbitans such as polyoxyethylene alkyl allyl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Fatty acid esters, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopal Te - DOO, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, may be mentioned polyoxyethylene sorbitan tristearate nonionic surfactants of polyoxyethylene sorbitan fatty acid esters such as such.

  These surfactants may be used alone or in several combinations.

  The amount of the surfactant used is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, based on the total amount of the positive resist composition (excluding the solvent).

Carboxylic acid onium salt The positive resist composition in the present invention may contain a carboxylic acid onium salt. Examples of the carboxylic acid onium salt include a carboxylic acid sulfonium salt, a carboxylic acid iodonium salt, and a carboxylic acid ammonium salt. In particular, as the carboxylic acid onium salt, an iodonium salt and a sulfonium salt are preferable. Furthermore, it is preferable that the carboxylate residue of the carboxylic acid onium salt of the present invention does not contain an aromatic group or a carbon-carbon double bond. As a particularly preferable anion moiety, a linear, branched, monocyclic or polycyclic alkylcarboxylic acid anion having 1 to 30 carbon atoms is preferable. More preferably, an anion of a carboxylic acid in which some or all of these alkyl groups are fluorine-substituted is preferable. The alkyl chain may contain an oxygen atom. This ensures transparency with respect to light of 220 nm or less, improves sensitivity and resolution, and improves density dependency and exposure margin.

  Fluorine-substituted carboxylic acid anions include fluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric acid, nonafluoropentanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorocyclohexanecarboxylic acid, 2 , 2-bistrifluoromethylpropionic acid anion and the like.

  These carboxylic acid onium salts can be synthesized by reacting sulfonium hydroxide, iodonium hydroxide, ammonium hydroxide and carboxylic acid with silver oxide in a suitable solvent.

  The content of the carboxylic acid onium salt in the composition is generally 0.1 to 20% by mass, preferably 0.5 to 10% by mass, more preferably 1 to 7% by mass, based on the total solid content of the composition. %.

Dissolution-inhibiting compound having a molecular weight of 3000 or less that decomposes by the action of an acid to increase the solubility in an alkali developer. (Hereinafter, also referred to as “dissolution inhibitor compound”), such as a cholic acid derivative containing an acid-decomposable group described in ProceedingofSPIE, 2724,355 (1996), in order not to lower the permeability of 220 nm or less. An alicyclic or aliphatic compound containing an acid-decomposable group is preferred. Examples of the acid-decomposable group and alicyclic structure are the same as those described for the resins (A1) and (A2).

  When the positive resist composition of the present invention is exposed with a KrF excimer laser or irradiated with an electron beam, it preferably contains a structure in which the phenolic hydroxyl group of the phenol compound is substituted with an acid-decomposable group. As a phenol compound, what contains 1-9 phenol frame | skeleton is preferable, More preferably, it contains 2-6 pieces.

  The molecular weight of the dissolution inhibiting compound in the present invention is 3000 or less, preferably 300 to 3000, and more preferably 500 to 2500.

  The addition amount of the dissolution inhibiting compound is preferably 3 to 50% by mass, more preferably 5 to 40% by mass, based on the solid content of the positive resist composition.

  Specific examples of the dissolution inhibiting compound are shown below, but the present invention is not limited thereto.

Other Additives In the positive resist composition of the present invention, if necessary, a dye, a plasticizer, a photosensitizer, a light absorber, and a compound that promotes solubility in a developer (for example, a molecular weight of 1000 or less) A phenol compound, an alicyclic compound having a carboxyl group, or an aliphatic compound).

Such phenolic compounds having a molecular weight of 1000 or less can be obtained by referring to, for example, the methods described in JP-A-4-1222938, JP-A-2-28531, US Pat. No. 4,916,210, European Patent 219294, etc. It can be easily synthesized by those skilled in the art.
Specific examples of alicyclic or aliphatic compounds having a carboxyl group include carboxylic acid derivatives having a steroid structure such as cholic acid, deoxycholic acid, lithocholic acid, adamantane carboxylic acid derivatives, adamantane dicarboxylic acid, cyclohexane carboxylic acid, cyclohexane Examples thereof include, but are not limited to, dicarboxylic acids.

Pattern Forming Method The positive resist composition of the present invention is preferably used at a film thickness of 30 to 250 nm, more preferably at a film thickness of 30 to 200 nm, from the viewpoint of improving resolution. Such a film thickness can be obtained by setting the solid content concentration in the positive resist composition to an appropriate range to give an appropriate viscosity and improving the coating property and film forming property.
The total solid content concentration in the positive resist composition is generally 1 to 10% by mass, more preferably 1 to 8.0% by mass, and still more preferably 1.0 to 6.0% by mass.

  The positive resist composition of the present invention is used by dissolving the above components in a predetermined organic solvent, preferably the mixed solvent, filtering the solution, and then applying the solution on a predetermined support as follows. The filter used for filter filtration is preferably made of polytetrafluoroethylene, polyethylene, or nylon of 0.1 microns or less, more preferably 0.05 microns or less, and still more preferably 0.03 microns or less.

For example, a positive resist composition is coated on a substrate (eg, silicon / silicon dioxide coating) used for manufacturing a precision integrated circuit element by an appropriate coating method such as a spinner or a coater, and dried to form a resist film. Form.
The resist film is irradiated with actinic rays or radiation through a predetermined mask, preferably baked (heated), developed and rinsed. Thereby, a good pattern can be obtained.

Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., preferably 250 nm or less, more preferably 220 nm or less, particularly preferably 1 to 1. Far-ultraviolet light with a wavelength of 200 nm, specifically, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (157 nm), X-ray, electron beam, etc., ArF excimer laser, EUV ( 13 nm), an electron beam is preferred.

Before forming the resist film, an antireflection film may be coated on the substrate in advance.
As the antireflection film, any of an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, and amorphous silicon, and an organic film type made of a light absorber and a polymer material can be used. In addition, as the organic antireflection film, commercially available organic antireflection films such as DUV30 series, DUV-40 series manufactured by Brewer Science, AR-2, AR-3, AR-5 manufactured by Shipley are also used. it can.

In the development step, an alkaline developer is used as follows. Examples of the alkali developer for the positive resist composition include inorganic hydroxides such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, and primary amines such as ethylamine and n-propylamine. Secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide Alkaline aqueous solutions of cyclic amines such as quaternary ammonium salts such as pyrrole and pihelidine can be used.
Furthermore, alcohols and surfactants can be added in appropriate amounts to the alkaline developer.
The alkali concentration of the alkali developer is usually from 0.1 to 20% by mass.
The pH of the alkali developer is usually from 10.0 to 15.0.
Furthermore, alcohols and surfactants can be added in appropriate amounts to the alkaline aqueous solution.
As the rinsing liquid, pure water can be used, and an appropriate amount of a surfactant can be added.
Further, after the development process or the rinsing process, a process of removing the developer or the rinsing liquid adhering to the pattern with a supercritical fluid can be performed.

  After applying the positive resist composition of the present invention to form a resist film, exposure is performed by filling a liquid (immersion medium) having a refractive index higher than air between the resist film and the lens during irradiation with actinic rays or radiation. (Immersion exposure) may be performed. Thereby, resolution can be improved. As the immersion medium to be used, any liquid can be used as long as it has a higher refractive index than air, but pure water is preferred.

The immersion liquid used for the immersion exposure will be described below.
The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a refractive index temperature coefficient as small as possible so as to minimize distortion of the optical image projected onto the resist film. Is an ArF excimer laser (wavelength; 193 nm), it is preferable to use water from the viewpoints of availability and ease of handling in addition to the above-mentioned viewpoints.
Further, a medium having a refractive index of 1.5 or more can be used in that the refractive index can be further improved. This medium may be an aqueous solution or an organic solvent.

  When water is used as the immersion liquid, the surface tension of the water is decreased and the surface activity is increased, so that the resist film on the wafer is not dissolved and the influence on the optical coating on the lower surface of the lens element can be ignored. An additive (liquid) may be added in a small proportion. The additive is preferably an aliphatic alcohol having a refractive index substantially equal to that of water, and specifically includes methyl alcohol, ethyl alcohol, isopropyl alcohol and the like. By adding an alcohol having a refractive index substantially equal to that of water, even if the alcohol component in water evaporates and the content concentration changes, an advantage that the change in the refractive index of the entire liquid can be made extremely small can be obtained. On the other hand, when an opaque material or impurities whose refractive index is significantly different from that of water are mixed with 193 nm light, the optical image projected on the resist film is distorted. . Further, pure water filtered through an ion exchange filter or the like may be used.

The electrical resistance of water is desirably 18.3 MQcm or more, the TOC (organic substance concentration) is desirably 20 ppb or less, and deaeration treatment is desirably performed.
Moreover, it is possible to improve lithography performance by increasing the refractive index of the immersion liquid. From such a viewpoint, an additive for increasing the refractive index may be added to water, or heavy water (D ₂ O) may be used instead of water.

When the resist film made of the positive resist composition of the present invention is exposed through an immersion medium, (F) a hydrophobic resin (HR) can be further added as necessary. As a result, hydrophobic resin (HR) is unevenly distributed on the surface of the resist film, and when the immersion medium is water, the receding contact angle of the resist film surface with respect to the water when the resist film is formed is improved, and the immersion water tracking is improved. Can be made. As the hydrophobic resin (HR), any resin can be used as long as the receding contact angle of the surface can be improved by addition, but a resin having at least one of fluorine atom and silicon atom is preferable. The receding contact angle of the resist film is preferably 60 ° to 90 °, more preferably 70 ° or more. The addition amount can be adjusted and used as appropriate so that the receding contact angle of the resist film falls within the above range, but is preferably 0.1 to 10% by mass based on the total solid content of the positive resist composition, More preferably, it is 0.1-5 mass%. Hydrophobic resin (HR) is ubiquitous at the interface as described above, but unlike a surfactant, it does not necessarily have a hydrophilic group in the molecule, and polar / nonpolar substances are mixed uniformly. There is no need to contribute.
The receding contact angle is the contact angle measured when the contact line at the droplet-substrate interface recedes, and is useful for simulating the ease of droplet movement under dynamic conditions. It is generally known. In simple terms, it can be defined as the contact angle when the droplet interface recedes when the droplet discharged from the needle tip is deposited on the substrate and then sucked into the needle again. It can be measured by using a contact angle measuring method generally called an expansion / contraction method.
In the immersion exposure process, the immersion head needs to move on the wafer following the movement of the exposure head to scan the wafer at high speed to form the exposure pattern. In this case, the contact angle of the immersion liquid with respect to the resist film is important, and the resist is required to follow the high-speed scanning of the exposure head without remaining droplets.

  The fluorine atom or silicon atom in the hydrophobic resin (HR) may be contained in the main chain of the resin or may be substituted on the side chain.

The hydrophobic resin (HR) is preferably a resin having an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom as a partial structure having a fluorine atom.
The alkyl group having a fluorine atom (preferably having 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms) is a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, It may have a substituent.
The cycloalkyl group having a fluorine atom is a monocyclic or polycyclic cycloalkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and may further have another substituent.
Examples of the aryl group having a fluorine atom include those in which at least one hydrogen atom of an aryl group such as a phenyl group or a naphthyl group is substituted with a fluorine atom, and may further have another substituent.

  Preferred examples of the alkyl group having a fluorine atom, the cycloalkyl group having a fluorine atom, or the aryl group having a fluorine atom include groups represented by the following general formulas (F2) to (F4). The present invention is not limited to this.

In general formulas (F2) to (F4),
R _{57 to} R ₆₈ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{57 to} R ₆₁ , R _{62 to} R ₆₄ and R _{65 to} R ₆₈ is a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom (preferably having a carbon number of 1 ~ 4). R _{57 to} R ₆₁ and R _{65 to} R ₆₇ are preferably all fluorine atoms. R ₆₂ , R ₆₃ and R ₆₈ are preferably an alkyl group (preferably having 1 to 4 carbon atoms) in which at least one hydrogen atom is substituted with a fluorine atom, and preferably a perfluoroalkyl group having 1 to 4 carbon atoms. Further preferred. R ₆₂ and R ₆₃ may be connected to each other to form a ring.

Specific examples of the group represented by the general formula (F2) include a p-fluorophenyl group, a pentafluorophenyl group, and a 3,5-di (trifluoromethyl) phenyl group.
Specific examples of the group represented by the general formula (F3) include trifluoromethyl group, pentafluoropropyl group, pentafluoroethyl group, heptafluorobutyl group, hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2 -Methyl) isopropyl group, nonafluorobutyl group, octafluoroisobutyl group, nonafluorohexyl group, nonafluoro-t-butyl group, perfluoroisopentyl group, perfluorooctyl group, perfluoro (trimethyl) hexyl group, 2,2 1,3,3-tetrafluorocyclobutyl group, perfluorocyclohexyl group and the like. Hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2-methyl) isopropyl group, octafluoroisobutyl group, nonafluoro-t-butyl group and perfluoroisopentyl group are preferable, and hexafluoroisopropyl group and heptafluoroisopropyl group are preferable. Further preferred.
Specific examples of the group represented by the general formula (F4) include, for example, —C (CF ₃ ) ₂ OH, —C (C ₂ F ₅ ) ₂ OH, —C (CF ₃ ) (CH ₃ ) OH, -CH (CF ₃₎ OH and the like, -C (CF _{3) 2} OH is preferred.

Hereinafter, although the specific example of the repeating unit which has a fluorine atom is shown, this invention is not limited to this.
In specific examples, X ₁ represents a hydrogen atom, —CH ₃ , —F or —CF ₃ .
X ₂ represents —F or —CF ₃ .

The hydrophobic resin (HR) is preferably a resin having an alkylsilyl structure (preferably a trialkylsilyl group) or a cyclic siloxane structure as a partial structure having a silicon atom.
Specific examples of the alkylsilyl structure or the cyclic siloxane structure include groups represented by the following general formulas (CS-1) to (CS-3).

In general formulas (CS-1) to (CS-3),
R _{12 to} R ₂₆ each independently represents a linear or branched alkyl group (preferably having 1 to 20 carbon atoms) or a cycloalkyl group (preferably having 3 to 20 carbon atoms).
L < ₃ > -L < ₅ > represents a single bond or a bivalent coupling group. As the divalent linking group, an alkylene group, a phenyl group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a urethane group, or a urea group is used alone or in combination of two or more groups. A combination is mentioned.
n represents an integer of 1 to 5.

Hereinafter, although the specific example of the repeating unit which has group represented by general formula (CS-1)-(CS-3) is given, this invention is not limited to this. In specific examples, X ₁ represents a hydrogen atom, —CH ₃ , —F or —CF ₃ .

Furthermore, the hydrophobic resin (HR) may have at least one group selected from the following groups (x) to (z).
(X) an alkali-soluble group,
(Y) a group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer;
(Z) A group that decomposes by the action of an acid.

(X) Alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) ( Alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) ) And a methylene group.
Preferred alkali-soluble groups include fluorinated alcohol groups (preferably hexafluoroisopropanol), sulfonimide groups, and bis (carbonyl) methylene groups.

Examples of the repeating unit having an alkali-soluble group (x) include a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or a main group of the resin via a linking group. It is preferable to use a repeating unit in which an alkali-soluble group is bonded to the chain, and further introduce a polymerization initiator or chain transfer agent having an alkali-soluble group at the end of the polymer chain at the time of polymerization.
The content of the repeating unit having an alkali-soluble group (x) is preferably from 1 to 50 mol%, more preferably from 3 to 35 mol%, still more preferably from 5 to 20 mol%, based on all repeating units in the polymer.

  Specific examples of the repeating unit having an alkali-soluble group (x) are shown below, but the present invention is not limited thereto.

(Y) Examples of the group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer include a group having a lactone structure, an acid anhydride, an acid imide group, and the like, and preferably a lactone group It is.
As the repeating unit having a group (y) that is decomposed by the action of an alkali developer and increases the solubility in the alkali developer, an alkali is added to the main chain of the resin, such as a repeating unit of an acrylate ester or a methacrylate ester. A polymerization initiator having a repeating unit to which a group (y) that decomposes by the action of the developer and increases the solubility in an alkali developer is bonded, or a group (y) that increases the solubility in an alkali developer And a chain transfer agent used at the time of polymerization are preferably introduced at the end of the polymer chain.
The content of the repeating unit having a group (y) whose solubility in an alkali developer is increased is preferably 1 to 40 mol%, more preferably 3 to 30 mol%, still more preferably based on all repeating units in the polymer. 5 to 15 mol%.

  Specific examples of the repeating unit having a group (y) that increases the solubility in an alkali developer include the same repeating units as those having the lactone structure described in the resins (A1) and (A2). .

  In the hydrophobic resin (HR), the repeating unit having a group (z) that is decomposed by the action of an acid is the same as the repeating unit having an acid-decomposable group listed in the resins (A1) and (A2). Can be mentioned. In the hydrophobic resin (HR), the content of the repeating unit having a group (z) that is decomposed by the action of an acid is preferably 1 to 80 mol%, more preferably 10 to 10%, based on all repeating units in the polymer. 80 mol%, more preferably 20 to 60 mol%.

  The hydrophobic resin (HR) may further have a repeating unit represented by the following general formula (III).

In general formula (III):
R ₄ represents a group having an alkyl group, a cycloalkyl group, an alkenyl group, or a cycloalkenyl group.
L ₆ represents a single bond or a divalent linking group.

In general formula (III), the alkyl group represented by R ₄ is preferably a linear or branched alkyl group having 3 to 20 carbon atoms.
The cycloalkyl group is preferably a cycloalkyl group having 3 to 20 carbon atoms.
The alkenyl group is preferably an alkenyl group having 3 to 20 carbon atoms.
The cycloalkenyl group is preferably a cycloalkenyl group having 3 to 20 carbon atoms.
The divalent linking group of L ₆ is preferably an alkylene group (preferably having 1 to 5 carbon atoms) or an oxy group.

When the hydrophobic resin (HR) has a fluorine atom, the fluorine atom content is preferably 5 to 80% by mass, and 10 to 80% by mass with respect to the molecular weight of the hydrophobic resin (HR). Is more preferable. Moreover, it is preferable that the repeating unit containing a fluorine atom is 10-100 mass% in hydrophobic resin (HR), and it is more preferable that it is 30-100 mass%.
When the hydrophobic resin (HR) has a silicon atom, the content of the silicon atom is preferably 2 to 50% by mass and preferably 2 to 30% by mass with respect to the molecular weight of the hydrophobic resin (HR). Is more preferable. Moreover, it is preferable that it is 10-100 mass% in hydrophobic resin (HR), and, as for the repeating unit containing a silicon atom, it is more preferable that it is 20-100 mass%.

  The weight average molecular weight of the hydrophobic resin (HR) in terms of standard polystyrene is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and even more preferably 2,000 to 15,000. is there.

  The hydrophobic resin (HR), like the resins (A1) and (A2), naturally has few impurities such as metals, and the residual monomer and oligomer components are preferably 0 to 10% by mass, More preferably, it is 0-5 mass%, and 0-1 mass% is still more preferable. Thereby, a resist having no change over time such as foreign matter in liquid or sensitivity can be obtained. The molecular weight distribution (Mw / Mn, also referred to as dispersity) is preferably in the range of 1 to 5, more preferably 1 to 3, and still more preferably from the viewpoints of resolution, resist shape, resist pattern sidewall, roughness, and the like. It is the range of 1-2.

  As the hydrophobic resin (HR), various commercially available products can be used, or they can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as the solvent used in the positive resist composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.

  The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. The concentration of the reaction is 5 to 50% by mass, preferably 30 to 50% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.

  After completion of the reaction, the mixture is allowed to cool to room temperature and purified. Purification can be accomplished by a liquid-liquid extraction method that removes residual monomers and oligomer components by combining water and an appropriate solvent, and a purification method in a solution state such as ultrafiltration that extracts and removes only those having a specific molecular weight or less. , Reprecipitation method that removes residual monomer by coagulating resin in poor solvent by dripping resin solution into poor solvent and purification in solid state such as washing filtered resin slurry with poor solvent A normal method such as a method can be applied. For example, the resin is precipitated as a solid by contacting a solvent (poor solvent) in which the resin is hardly soluble or insoluble in a volume amount of 10 times or less, preferably 10 to 5 times that of the reaction solution.

  The solvent (precipitation or reprecipitation solvent) used in the precipitation or reprecipitation operation from the polymer solution may be a poor solvent for the polymer, and may be a hydrocarbon, halogenated hydrocarbon, nitro, depending on the type of polymer. A compound, ether, ketone, ester, carbonate, alcohol, carboxylic acid, water, a mixed solvent containing these solvents, and the like can be appropriately selected for use. Among these, as a precipitation or reprecipitation solvent, a solvent containing at least an alcohol (particularly methanol or the like) or water is preferable.

  The amount of the precipitation or reprecipitation solvent used can be appropriately selected in consideration of efficiency, yield, and the like, but generally 100 to 10000 parts by mass, preferably 200 to 2000 parts by mass with respect to 100 parts by mass of the polymer solution, More preferably, it is 300-1000 mass parts.

  The temperature for precipitation or reprecipitation can be appropriately selected in consideration of efficiency and operability, but is usually about 0 to 50 ° C., preferably around room temperature (for example, about 20 to 35 ° C.). The precipitation or reprecipitation operation can be performed by a known method such as a batch method or a continuous method using a conventional mixing vessel such as a stirring tank.

  The precipitated or re-precipitated polymer is usually subjected to conventional solid-liquid separation such as filtration and centrifugation, and dried before use. Filtration is performed using a solvent-resistant filter medium, preferably under pressure. Drying is performed at a temperature of about 30 to 100 ° C., preferably about 30 to 50 ° C. under normal pressure or reduced pressure (preferably under reduced pressure).

  The resin may be once deposited and separated, and then dissolved again in a solvent, and the resin may be brought into contact with a hardly soluble or insoluble solvent. That is, after completion of the radical polymerization reaction, a solvent in which the polymer is hardly soluble or insoluble is brought into contact, the resin is precipitated (step a), the resin is separated from the solution (step b), and dissolved again in the solvent. (Step c), and then contact the resin solution A with a solvent in which the resin is hardly soluble or insoluble in a volume amount less than 10 times that of the resin solution A (preferably 5 times or less volume). This may be a method including precipitating a resin solid (step d) and separating the precipitated resin (step e).

  Specific examples of the hydrophobic resin (HR) are shown below. Table 1 below shows the molar ratio of repeating units in each resin (corresponding to each repeating unit in order from the left), the weight average molecular weight, and the degree of dispersion.

Since the resist film is not directly brought into contact with the immersion liquid between the resist film of the positive resist composition of the present invention and the immersion liquid, it is also referred to as an “immersion liquid hardly soluble film” (hereinafter referred to as “top coat”). ) May be provided. The necessary functions for the top coat are suitability for application to the upper layer of the resist, radiation, especially transparency to 193 nm, and poor immersion liquid solubility. It is preferable that the top coat is not mixed with the resist and can be uniformly applied to the resist upper layer.
From the viewpoint of 193 nm transparency, the top coat is preferably a polymer that does not contain abundant aromatics. Specifically, the polymer contains a hydrocarbon polymer, an acrylate polymer, polymethacrylic acid, polyacrylic acid, polyvinyl ether, and silicon. Examples thereof include a polymer and a fluorine-containing polymer. The aforementioned hydrophobic resin (HR) is also suitable as a top coat. From the viewpoint of contaminating the optical lens when impurities are eluted from the top coat into the immersion liquid, it is preferable that the residual monomer component of the polymer contained in the top coat is small.

When peeling the top coat, a developer may be used, or a separate release agent may be used. As the release agent, a solvent having a small penetration into the resist film is preferable. It is preferable that the peeling process can be performed with an alkali developer in that the peeling process can be performed simultaneously with the resist film development process. From the viewpoint of peeling with an alkaline developer, the topcoat is preferably acidic, but may be neutral or alkaline from the viewpoint of non-intermixability with the resist film.
The resolution is improved when there is no difference in refractive index between the top coat and the immersion liquid. In the case of using water as the immersion liquid in an ArF excimer laser (wavelength: 193 nm), the top coat for ArF immersion exposure is preferably close to the refractive index of the immersion liquid. From the viewpoint of making the refractive index close to the immersion liquid, it is preferable to have fluorine atoms in the topcoat. A thin film is more preferable from the viewpoint of transparency and refractive index.

  The top coat is preferably not mixed with the resist film and further not mixed with the immersion liquid. From this point of view, when the immersion liquid is water, the solvent used for the top coat is preferably a water-insoluble medium that is hardly soluble in the solvent used for the positive resist composition. Furthermore, when the immersion liquid is an organic solvent, the topcoat may be water-soluble or water-insoluble.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example. In addition, Example 7 and 8 shall be read as a reference example.

Synthesis Example / Synthesis of Resin (P-7) Component 1 (19.78 g), Component 2 (5.05 g), Component 3 (10.92 g) and Component 4 (6.72 g) were charged and dissolved in cyclohexanone (157.54 g) to obtain a solid content. A solution having a concentration of 15% by mass was prepared. To this solution, 2.993 g of a polymerization initiator (Wako Pure Chemicals V-601) was added, and this was added dropwise to 84.83 g of a cyclohexanone solution heated to 80 ° C. in a nitrogen atmosphere over 6 hours. The reaction liquid was stirred for 2 hours after completion | finish of dripping. After completion of the reaction, the reaction solution was cooled to room temperature, crystallized in 2017 g of a mixed solvent of hexane / ethyl acetate = 7/3 (mass ratio), and the precipitated white powder was collected by filtration, and the target resin (P- 7) was recovered.

The weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement of the obtained resin was 10000, and dispersion degree was 1.9.
The monomer units are defined as component 1, component 2, component 3, and component 4 in order from the left side of the repeating unit in the resin structure, and the composition ratios are shown in the table.

  The structures of the used resins (A1) and (A2) are shown. In the table, the composition ratio represents mol% in order from the left of the structural formula.

<Registration adjustment>
A resist solution is prepared by dissolving the components shown in the following table and 100 ppm of surfactant (PF6320: OMNOVA fluorine-based surfactant) with respect to the total solid content in a solvent, and having a pore size of 0.1 μm. A positive resist composition was prepared by filtration through a polyethylene filter. The prepared positive resist composition was evaluated by the following method, and the results are shown in the table.
In Table 3 , when the positive resist composition contains a hydrophobic resin (HR), the addition form is marked as “addition”.
Hydrophobic additive resins having the following structure and a copolymerization ratio of 50/50 and Mw of 7000 were used, and the receding contact angle with respect to water after film formation was 70 degrees so that the total solid content of each composition was 0.00. It added between 1-1.0% and prepared the resist.

<Formation of resist pattern>
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. The positive resist composition prepared thereon was applied and baked at 100 ° C. for 60 seconds to form a 90 nm resist film. Using the obtained wafer ArF excimer laser scanner (PAS5500 / 1100, NA0.75 manufactured by ASML), exposure was performed through a 6% halftone mask of 85 nm 1: 1 line and space pattern. Thereafter, heating was performed at 110 ° C. for 60 seconds, followed by development with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsing with pure water, and spin drying to obtain a resist pattern.

<Dry etching resistance evaluation (speed, surface roughness)>
The obtained resist pattern was dry-etched with HITACHI U-621 using Ar / C ₄ F ₆ / O ₂ gas for 30 seconds, and the dry etching (DE) rate was measured.
Further, surface roughness in a cross-sectional SEM was observed with HITACHI S4800, and used as an index of DE resistance.
An example of a surface with good surface roughness is shown in FIG. 1, and an example of a non-uniform surface is shown in FIG.

<Pattern shape and defocus latitude>
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer and baked at 205 ° C. for 60 seconds to form a 98 nm antireflection film. The positive resist composition prepared thereon was applied and baked at 100 ° C. for 60 seconds to form a 90 nm resist film. The obtained wafer was exposed through a 6% halftone mask with a 50 nm 1: 1 line and space pattern using an ArF excimer laser immersion scanner (XT1700i, NA 1.20 manufactured by ASML). Ultra pure water was used as the immersion medium. Thereafter, heating was performed at 110 ° C. for 60 seconds, followed by development with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 10 seconds, rinsing with pure water, and spin drying to obtain a resist pattern.
The shape and defocus latitude (DOF; depth of focus) of the obtained pattern were confirmed by HITACHI S9380 and HITACHI S4800.
In addition, when the cross-sectional SEM observation shows that the dimensional difference between the top and the bottom is 5 nm or less, ◯, 5 nm to 10 nm are Δ, and 10 nm or more are x.

  The pattern shape of Comparative Example 1 had an undercut.

  The abbreviations in the table indicate the following.

PAG1: Triphenylsulfonium nonaflate PAG2: z66 below

Q-1: Dibutylaniline Q-2: N, N-dihydroxyethylaniline

SL-1: Cyclohexanone SL-2: Propylene glycol monomethyl ether acetate SL-3: Ethyl lactate SL-4: Propylene glycol monomethyl ether

This is an example of a surface with good surface roughness after dry etching. This is an example of non-uniform surface roughness after dry etching.

Claims (16)

Resin (A1) whose alkali solubility is increased by the reaction of an acid having a repeating unit represented by the following general formula (1) and a repeating unit represented by the general formula (2),
Resin (A2) whose alkali solubility is increased by the reaction of an acid having a repeating unit represented by the following general formula (3) and a repeating unit represented by the general formula (4), and
Compound (B) that generates acid upon irradiation with actinic ray or radiation,
Wherein the repeating unit represented by the general formula (4) does not contain a group that decomposes under the action of an acid, and further comprises a fluorine atom and a silicon atom. A positive resist composition comprising a hydrophobic resin having at least one of them.

In general formula (1),
Xa ₁ represents a hydrogen atom, a halogen atom, or an alkyl group.
T represents a single bond or a divalent linking group.
Rx _{1 to} Rx ₃ each independently represents an alkyl group or a cycloalkyl group.
At least two of Rx _{1 to} Rx ₃ may be bonded to form a cycloalkyl group.
In general formula (2),
Rb ₀ represents a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 4 carbon atoms.
Ab represents a single bond, an alkylene group, a divalent linking group having an alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these.
V represents a partial structure of any of the following LC1-3, LC1-4, LC1-7, LC1-8, LC1-9, and LC1-10.

Where
Rb ₂ represents an arbitrary substituent.
n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of Rb ₂ may be the same or different, or a plurality of Rb ₂ may be bonded to form a ring.
* Represents a bond to Ab in Formula (2), and represents that it can be bonded to Ab at any position even if the lactone ring is polycyclic.

In general formula (3),
Xa ₂ represents a hydrogen atom, a halogen atom or an alkyl group.
T ₂ represents a single bond or a divalent linking group.
Rx _{4 to} Rx ₆ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Rx _{4 to} Rx ₆ may combine to form a cycloalkyl group.
In general formula (4),
Rb ₁ represents a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 4 carbon atoms.
Ac represents a single bond, an alkylene group, a divalent linking group having an alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these.
W represents an alkyl group having 6 to 20 carbon atoms, an unsubstituted cycloalkyl group having 6 to 20 carbon atoms, or an aryl group.   2. The positive resist composition according to claim 1, wherein the addition amount of the hydrophobic resin is 0.1 to 10% by mass based on the total solid content of the positive resist composition.   The positive resist composition according to claim 1, wherein the hydrophobic resin has a group that is decomposed by the action of (z) an acid.   The positive resist composition according to claim 1, wherein the resin (A2) further has a repeating unit having a lactone structure. The positive resist composition according to any one of claims 1 to 4, wherein the repeating unit represented by the general formula (1) is a repeating unit represented by the following general formula (I). object.

In general formula (I):
R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group.
R ² represents an alkyl group.
When there are a plurality of R ^{3 s} , each independently represents a halogen atom, an alkyl group, a cycloalkyl group, a cyano group or a hydroxyl group.
Z represents a cycloalkyl group having 3 to 8 carbon atoms.
n represents 0 or a positive integer. The positive resist composition according to claim 5, wherein the repeating unit represented by the general formula (I) is a repeating unit represented by the following general formula (II).
In the general formula (II), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group.   Furthermore, the positive resist composition of any one of Claims 1-6 containing the monoketone compound which may contain a ring as a solvent.   The positive resist composition according to claim 7, wherein the monoketone compound which may contain a ring is cyclohexanone.   The ratio between the resin (A1) and the resin (A2) is 90:10 to 30:70 in a weight ratio of (A1) :( A2). The positive resist composition as described in 1. above.   The ratio of said resin (A1) and said resin (A2) is 70: 30-50: 50 by weight ratio of (A1) :( A2), Any one of Claims 1-9 characterized by the above-mentioned. The positive resist composition as described in 1. above.   The positive resist composition according to claim 1, wherein the resin (A1) and the resin (A2) do not have an aromatic group.   The said resin (A1) and the said resin (A2) are resin in which all the repeating units were comprised by the (meth) acrylate type repeating unit, The any one of Claims 1-11 characterized by the above-mentioned. Positive resist composition. In the said General formula (4), W is a C6-C20 alkyl group or a C6-C20 unsubstituted cycloalkyl group, The one of Claims 1-12 characterized by the above-mentioned. Positive resist composition.   A resist film formed from the positive resist composition according to claim 1.   The pattern formation method characterized by exposing and developing the resist film of Claim 14.   The pattern forming method according to claim 15, wherein the exposure is immersion exposure.