JP5037403B2 - Positive photosensitive composition and pattern forming method using the same - Google Patents

Description

  The present invention relates to a positive photosensitive composition used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, and other photofabrication processes.

  The chemically amplified resist composition generates an acid in the exposed area by irradiation with actinic rays or radiation such as far ultraviolet light, and a reaction solution using the acid as a catalyst to develop a developing solution for the irradiated and non-irradiated areas of the active light or radiation. It is a pattern forming material that changes the solubility in the substrate and forms a pattern on the substrate.

  When a KrF excimer laser is used as an exposure light source, a resin having a basic skeleton of poly (hydroxystyrene) having a small absorption mainly in the 248 nm region is used as a main component. A pattern is formed, which is a better system than the conventional naphthoquinone diazide / novolak resin system.

  On the other hand, when a further short wavelength light source, for example, 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. It wasn't.

For this reason, an ArF excimer laser resist containing a resin having an alicyclic hydrocarbon structure has been developed. Examples of the acid-decomposable resin that is a main constituent of the chemically amplified resist composition include structural units derived from a (meth) acrylic acid ester having a polycyclic alicyclic hydrocarbon structure such as an adamantane skeleton. Resin having a main unit having a structural unit derived from a (meth) acrylic acid ester having a monocyclic alicyclic hydrocarbon structure such as a resin having a main chain (see, for example, Patent Document 1) or a cyclohexane skeleton (See, for example, Patent Document 2).
It has also been found that a high-resolution resist can be obtained by including a repeating unit having acetal-protected methacrylic acid. (For example, see Patent Document 3).

However, from the viewpoint of overall performance as a resist, it is actually difficult to find an appropriate combination of resin, photoacid generator, additive, solvent, etc. to be used, and the line width is 100 nm or less. When forming such a fine pattern, improvement of the exposure latitude and the line edge roughness performance of the line pattern has been demanded.
Japanese Patent No. 2881969 International Publication No. 2005/016982 Pamphlet JP 2006-96965 A

  An object of the present invention is to provide a positive photosensitive composition having improved exposure latitude and line edge roughness performance, and a pattern forming method using the same.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems.
The present invention is as follows.

(1) (A) a resin having a repeating unit represented by the general formula (I) and a repeating unit represented by the general formula (II) that generates a carboxylic acid by the action of an acid, and (B) an actinic ray or A positive photosensitive composition comprising a compound that generates an acid upon irradiation with radiation.

In general formula (I),
R ₁ , R ₂ and R ₃ each independently represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted cycloalkyl group. R ₂ and R ₃ may be bonded to each other to form a ring structure.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group, or an acyl group.
The van der Waals volume of the structure represented by the general formula (I) is 306 × 10 ⁻³⁰ m ³ or less.

In general formula (II),
R ₄ represents a hydrocarbon group having 20 or less carbon atoms.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group.
n represents an integer of 0 to 5.

  (2) The positive photosensitive composition as described in (1), wherein the resin (A) further has a repeating unit containing a lactone group.

(3) The positive photosensitive composition as described in (1) or (2), wherein the resin (A) further has a repeating unit represented by the general formula (III).

In general formula (III), R ₅ represents a alicyclic hydrocarbon structure having a hydroxyl group or a cyano group.

Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group.

(4) The positive photosensitive composition as described in any one of (1) to (3), wherein the resin (A) further has a repeating unit represented by the general formula (IV).

In general formula (IV), R ₆ represents a hydrocarbon group having at least one cyclic structure and having neither a hydroxyl group nor a cyano group.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group.

  (5) A pattern forming method comprising a step of forming a film using the positive photosensitive composition according to any one of (1) to (4), and exposing and developing the film. .

  According to the positive photosensitive composition of the present invention, a pattern with improved exposure latitude and line edge roughness performance can be formed.

Hereinafter, 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 substituted and unsubstituted includes what has a substituent with the thing which 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).

[1] Resin having a repeating unit represented by the general formula (I) and a repeating unit represented by the general formula (II) that generates a carboxylic acid by the action of an acid (component (A))
The positive photosensitive composition of the present invention is represented by the general formula (I) that generates a carboxylic acid by the action of an acid and the general formula (II) that generates a carboxylic acid by the action of an acid. A resin having a repeating unit (hereinafter also referred to as “resin (A)”).
First, the repeating unit represented by the general formula (I) that generates a carboxylic acid by the action of an acid will be described.

In general formula (I):
R ₁ , R ₂ and R ₃ each independently represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted cycloalkyl group. R ₂ and R ₃ may be bonded to each other to form a ring structure. However, the van der Waals volume of the structure represented by the general formula (I) is 306 × 10 ⁻³⁰ m ³ or less.

Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group.
General formula (I) will be described in more detail.
R ₁ represents an alkyl group which may have a substituent or a cycloalkyl group which may have a substituent. The alkyl group as R ₁ may be linear or branched, and is preferably an alkyl group having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms. The cycloalkyl group as R ₁ is preferably a cycloalkyl group having 3 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, an isopropyl group, a cyclopentyl group, a cyclohexyl group, and the like, and a methyl group, an ethyl group, and an isopropyl group are particularly preferable.

R ₂ and R ₃ represent an alkyl group which may have a substituent or a cycloalkyl group which may have a substituent. The alkyl group as R ₂ and R ₃ may be linear or branched, preferably an alkyl group having 1 to 10 carbon atoms, and may have an oxygen atom, a sulfur atom, or a nitrogen atom in the alkyl chain. Good. Specifically, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-dodecyl group, n-tetradecyl group, n-octadecyl group, etc. And a branched alkyl group such as isopropyl group, isopropyl group, isobutyl group, t-butyl group, neopentyl group, 2-ethylhexyl group.

The cycloalkyl group as R ₂ and R ₃ is preferably a cycloalkyl group having 3 to 10 carbon atoms, may be polycyclic, and may have an oxygen atom in the ring. Specific examples include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, and cycloheptyl.

R ₂ and R ₃ may be the same or different, and may be bonded to each other to form a ring structure, more preferably a ring structure bonded to each other. Preferred ring structures include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. More preferred are a cyclopentyl group and a cyclohexyl group.

Examples of the substituent that each group of R _{1 to} R ₃ may have include, for example, a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxy group, a carbonyl group, and a cycloalkyl group (preferably having 3 to 10 carbon atoms). An aryl group (preferably 6 to 14 carbon atoms), an alkoxy group (preferably 1 to 10 carbon atoms), an acyl group (preferably 2 to 20 carbon atoms), an acyloxy group (preferably 2 to 10 carbon atoms), an alkoxy group Examples include a carbonyl group (preferably having 2 to 20 carbon atoms), an 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 aminoacyl group include 1 or 2 alkyl groups (preferably having 1 to 10 carbon atoms).

Ra represents a hydrogen atom, an alkyl group (preferably having 1 to 4 carbon atoms), or —CH ₂ —O—Ra ₂ . Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group. Preferred Ra is a hydrogen atom, a methyl group, or —CH ₂ —OH.

The van der Waals volume of the structure represented by the general formula (I) can be measured by means known in the art, and is calculated using, for example, the Standard procedure of CAChe Version 7.5.0.85 manufactured by Fujitsu. The In the present invention, the volume of the repeating unit represented by the general formula (I) determined by such a measuring method is 306 × 10 ⁻³⁰ m ³ or less, preferably 300 × 10 ⁻³⁰ m ³ or less, more preferably 285. × 10 ⁻³⁰ m ³ or less and 240 × 10 ⁻³⁰ m ³ or more.
Although the specific example of the repeating unit which has a preferable acid-decomposable group is shown below, this invention is not limited to this. The van der Waals volumes (hereinafter also referred to as “volumes”) of (1) to (24) are as shown in Table 1.

The content of the repeating unit represented by the general formula (I) that generates carboxylic acid by the action of an acid is preferably 20 to 90 mol%, more preferably, based on all repeating units in the resin (A). Is 30 to 50 mol%.
Next, the repeating unit represented by the general formula (II) that generates a carboxylic acid by the action of an acid will be described.

In general formula (II),
R ₄ represents a hydrocarbon group having 20 or less carbon atoms.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group.
n represents an integer of 0 to 5.

General formula (II) will be described in more detail.
R ₄ is a hydrocarbon group having 20 or less carbon atoms, and may have a substituent. The hydrocarbon group as R ₄ may be a linear or branched alkyl group, preferably a linear or branched alkyl group having 1 to 10 carbon atoms, having an oxygen atom, a sulfur atom, or a nitrogen atom in the alkyl chain. May be. Specifically, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-dodecyl group, n-tetradecyl group, n-octadecyl group, etc. And a branched alkyl group such as isopropyl group, isopropyl group, isobutyl group, t-butyl group, neopentyl group, 2-ethylhexyl group.

The hydrocarbon group as R ₄ may be a monocyclic hydrocarbon group or a polycyclic hydrocarbon group. Examples of the monocyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclo Examples thereof include cycloalkyl groups having 3 to 12 carbon atoms such as an octyl group, and cycloalkenyl groups having 3 to 12 carbon atoms such as a cyclohexenyl group. A preferable monocyclic hydrocarbon group is a monocyclic hydrocarbon group having 3 to 7 carbon atoms, and more preferable examples include a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group.

Examples of the polycyclic hydrocarbon group include a ring assembly hydrocarbon group and a bridged cyclic hydrocarbon group, and examples of the ring assembly hydrocarbon group include a bicyclohexyl group and a perhydronaphthalenyl group. As the bridged cyclic hydrocarbon ring, for example, bicyclic such as pinane, bornane, norpinane, norbornane, bicyclooctane ring (bicyclo [2.2.2] octane ring, bicyclo [3.2.1] octane ring, etc.) Hydrocarbon rings and tricyclic hydrocarbon rings such as homobredan, adamantane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [4.3.1.1 ^2,5 ] undecane ring, tetracyclo [ 4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, and tetracyclic hydrocarbon rings such as perhydro-1,4-methano-5,8-methanonaphthalene ring. The bridged cyclic hydrocarbon ring includes a condensed cyclic hydrocarbon ring such as perhydronaphthalene (decalin), perhydroanthracene, perhydrophenanthrene, perhydroacenaphthene, perhydrofluorene, perhydroindene, perhydroindene. A condensed ring in which a plurality of 5- to 8-membered cycloalkane rings such as a phenalene ring are condensed is also included.

  These alicyclic hydrocarbon groups and the linear and branched alkyl groups may have a substituent, and preferred substituents include a halogen atom, an alkyl group, a hydroxyl group protected with a protecting group, and a protecting group. And an amino group protected with. Preferred halogen atoms include bromine, chlorine and fluorine atoms, and preferred alkyl groups include methyl, ethyl, butyl and t-butyl groups. The above alkyl group may further have a substituent, and the substituent that may further have a halogen atom, an alkyl group, a hydroxyl group protected with a protecting group, an amino protected with a protecting group The group can be mentioned.

R ₄ is preferably a monocyclic hydrocarbon group or a polycyclic hydrocarbon group, more preferably a polycyclic hydrocarbon group, and particularly preferably an adamantyl group.
The specific description of Ra is the same as the description of Ra in the general formula (I).

As for the content rate of the repeating unit represented by general formula (II) which has an acid-decomposable group, 10-50 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 15-30 mol%. . Further, the content (mol%) of the repeating unit represented by the general formula (I) is preferably higher than the content of the repeating unit represented by the general formula (II).
Specific examples of the repeating unit represented by the general formula (II) are listed below, but the present invention is not limited thereto.

The resin (A) of the present invention 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. Here, the acid-decomposable group is, for example, a tertiary ester group. n2 represents an integer of 0 to 4. When n2 is 2 or more, a plurality of substituents (Rb ₂ ) may be the same or different, and a plurality of 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 is a group represented by the general formula (LC1 1 represents a group having a structure represented by any one of (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.

The resin (A) of the present invention preferably further contains a repeating unit having a hydroxyl group or a cyano group represented by the general formula (III). This improves the substrate adhesion and developer compatibility.

In general formula (III), R ₅ represents a alicyclic hydrocarbon structure having a hydroxyl group or a cyano group.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group. The specific description of Ra is the same as the description of Ra in the general formula (I).

The alicyclic hydrocarbon structure in R ₅ representing an alicyclic hydrocarbon structure having a hydroxyl group or a cyano group is preferably an adamantyl group, a diamantyl group, or a norbornane group as the alicyclic hydrocarbon structure. As the alicyclic hydrocarbon structure (R ₅ ) 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.

As the repeating unit represented by the general formula (III) having a partial structure represented by the general formulas (VIIa) to (VIId) as R ₅ , the repeating unit represented by the following general formulas (AIIa) to (AIId) Can be mentioned.

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 represented by the general formula (III) having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably 0 to 40 mol% with respect to all repeating units in the resin (A). More preferably, it is 0-30 mol%, More preferably, it is 5-20 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.

It is preferable that the resin (A) of the present invention further contains a repeating unit represented by the general formula (IV) that has neither a hydroxyl group nor a cyano group.

In general formula (IV), R ₆ represents a hydrocarbon group having at least one cyclic structure and having neither a hydroxyl group nor a cyano group.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group. The specific description of Ra is the same as the description of Ra in the general formula (I).

The cyclic structure possessed by R ₆ includes a monocyclic hydrocarbon group and a polycyclic hydrocarbon group. Examples of the monocyclic hydrocarbon group include cycloalkenyl having 3 to 12 carbon atoms such as cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and the like, and cycloalkyl groups having 3 to 12 carbon atoms and cyclohexenyl group. Groups. Preferable monocyclic hydrocarbon groups are monocyclic hydrocarbon groups having 3 to 7 carbon atoms, and more preferable examples include a cyclopentyl group and a cyclohexyl group.

The polycyclic hydrocarbon group includes a ring assembly hydrocarbon group and a bridged cyclic hydrocarbon group, and examples of the ring assembly hydrocarbon group include a bicyclohexyl group and a perhydronaphthalenyl group. As the bridged cyclic hydrocarbon ring, for example, bicyclic such as pinane, bornane, norpinane, norbornane, bicyclooctane ring (bicyclo [2.2.2] octane ring, bicyclo [3.2.1] octane ring, etc.) Hydrocarbon rings and tricyclic hydrocarbon rings such as homobredan, adamantane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [4.3.1.1 ^2,5 ] undecane ring, tetracyclo [ 4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, and tetracyclic hydrocarbon rings such as perhydro-1,4-methano-5,8-methanonaphthalene ring. The bridged cyclic hydrocarbon ring includes a condensed cyclic hydrocarbon ring such as perhydronaphthalene (decalin), perhydroanthracene, perhydrophenanthrene, perhydroacenaphthene, perhydrofluorene, perhydroindene, perhydroindene. A condensed ring in which a plurality of 5- to 8-membered cycloalkane rings such as a phenalene ring are condensed is also included.

Preferred examples of the bridged cyclic hydrocarbon ring include a norbornyl group, an adamantyl group, a bicyclooctanyl group, a tricyclo [5,2,1,0 ^2,6 ] decanyl group, and the like. More preferable examples of the bridged cyclic hydrocarbon ring include a norbornyl group and an adamantyl group.

  These alicyclic hydrocarbon groups may have a substituent, and preferred substituents include a halogen atom, an alkyl group, a hydroxyl group protected with a protecting group, an amino group protected with a protecting group, and the like. It is done. Preferred halogen atoms include bromine, chlorine and fluorine atoms, and preferred alkyl groups include methyl, ethyl, butyl and t-butyl groups. The above alkyl group may further have a substituent, and the substituent that may further have a halogen atom, an alkyl group, a hydroxyl group protected with a protecting group, an amino protected with a protecting group The group can be mentioned.

  Examples of the protecting group include an alkyl group, a cycloalkyl group, an aralkyl group, a substituted methyl group, a substituted ethyl group, an alkoxycarbonyl group, and an aralkyloxycarbonyl group. Preferred alkyl groups include alkyl groups having 1 to 4 carbon atoms, preferred substituted methyl groups include methoxymethyl, methoxythiomethyl, benzyloxymethyl, t-butoxymethyl, 2-methoxyethoxymethyl groups, and preferred substituted ethyl groups. 1-ethoxyethyl, 1-methyl-1-methoxyethyl, preferred acyl groups include formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, pivaloyl groups, etc., aliphatic acyl groups having 1 to 6 carbon atoms, alkoxycarbonyl Examples of the group include an alkoxycarbonyl group having 1 to 4 carbon atoms.

The content of the repeating unit represented by the general formula (IV) having neither a hydroxyl group nor a cyano group is preferably from 0 to 40 mol%, more preferably based on all repeating units in the resin (A). 0 to 20 mol%.
Specific examples of the repeating unit represented by the general formula (IV) are shown below, but the present invention is not limited thereto.

  The resin (A) of the present invention preferably has 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, 1-20 mol% is preferable with respect to all the repeating units in resin (A), 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.

The resin (A) of the present invention has, 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, sensitivity. Various repeating structural units can be included for the purpose of adjusting the etc.
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 resin (A), 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 resin (A), the molar ratio of each repeating structural unit is the resist dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and the general required performance of the resist, resolving power, heat resistance, sensitivity. It is set appropriately in order to adjust etc.

  When the positive photosensitive composition of the present invention is used for ArF exposure, the resin of component (B) preferably has no aromatic group from the viewpoint of transparency to ArF light.

  The resin (A) of the present invention is preferably one in which all 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, it has an acid-decomposable group represented by the general formula (II) and a (meth) acrylate-based repeating unit having an acid-decomposable group of 10 to 60 mol% and a general formula (II) ( (Meth) acrylate having a alicyclic hydrocarbon structure represented by the general formula (III) having a methacrylic group repeating unit of 10 to 55 mol%, a repeating unit of 0 to 55 mol% having a lactone group, and a hydroxyl group or a cyano group 0 to 20 mol% of system repeating units, 0 to 20 mol% of (meth) acrylate repeating units having a cyclic structure represented by the general formula (IV) having no hydroxyl group and cyano group, and other (meth) acrylates It is a copolymer containing 0 to 20 mol% of a system repeating unit.

  When the positive photosensitive composition of the present invention is irradiated with KrF excimer laser light, electron beam, X-ray, or high-energy light beam (EUV, etc.) having a wavelength of 50 nm or less, the resin (A) is further a hydroxystyrene type. It is preferable to have a repeating unit. More preferably, it has a hydroxystyrene-based repeating unit, an acid-decomposable repeating unit such as a hydroxystyrene-based repeating unit protected with an acid-decomposable group, and 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.

  Resin (A) 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 photosensitive composition of the present invention. Thereby, the generation of particles during storage 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 initiators 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 weight of the resin (A) is preferably 1,000 to 200,000, more preferably 2,000 to 20,000, and even more preferably 3,000 to 15 in terms of polystyrene by GPC method. 1,000, particularly preferably 5,000 to 12,000. 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, and more 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.

  The content of the resin (A) in the positive photosensitive composition is preferably 80 to 99.9% by mass, more preferably 90 to 99% by mass, based on the total solid content of the positive photosensitive composition. is there.

[2] Compound that generates acid upon irradiation with actinic rays or radiation (component (B))
The positive photosensitive composition of the present invention contains a compound that generates an acid upon irradiation with actinic rays or radiation (hereinafter also referred to as “acid generator”).

  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 etc. 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, such as US Pat. No. 3,849,137, German Patent No. No. 3914407, JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, JP-A 63-146038, JP-A 63-163452, The compounds described in JP-A-62-153853 and 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, etc. 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 1-30, 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 1 to 15 carbon atoms), alkyliminosulfonyl group (preferably 2 to 15 carbon atoms), ant 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 benzyl group, phenethyl group, naphthylmethyl group, naphthylethyl group, naphthylmethyl group and the like.

  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. These are 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.

Next, the compound (ZI-3) will be described.
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.

Next, general formulas (ZII) and (ZIII) will be described.
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 photosensitive composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, based on the total solid content of the positive photosensitive composition. More preferably, it is 1-7 mass%.

[3] Basic compound (component (C))
The positive photosensitive 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) and (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 the general formulas (A) and (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. It is an oxyethylene 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 preferable. It is an oxyethylene 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. It is an oxyethylene 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. It is an oxyethylene 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 the total solid of a positive photosensitive composition, Preferably it is 0.01-5 mass%.
The use ratio of the acid generator (B) and the basic compound (C) 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.

[4] Surfactant (component (D))
The positive photosensitive 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, fluorine atom and silicon atom) It is more preferable to contain any one or two or more surfactants having both.

  When the positive photosensitive composition of the present invention contains the above-mentioned surfactant, a resist pattern with good sensitivity and resolution and less adhesion and development defects can be obtained when using an exposure light source of 250 nm or less, particularly 220 nm or less. It becomes possible to give.

  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 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total solid content of the positive photosensitive composition.

[5] Dissolution inhibitor compound (component (E))
The positive photosensitive composition of the present invention contains a dissolution-inhibiting compound having a molecular weight of 3000 or less (hereinafter also referred to as “dissolution-inhibiting compound”) that decomposes by the action of an acid and increases the solubility in an alkaline developer. May be. As a dissolution inhibiting compound, a fat containing an acid-decomposable group such as a cholic acid derivative containing an acid-decomposable group described in Proceeding of SPIE, 2724, 355 (1996) is used because it does not lower the permeability below 220 nm. Cyclic or aliphatic compounds are preferred. Examples of the acid-decomposable group and alicyclic structure are the same as those described for the resin (A).

  When the positive photosensitive 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 preferably 3000 or less, more preferably 300 to 3000, and still 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 total solid content of the positive photosensitive composition.
Specific examples of the dissolution inhibiting compound are shown below, but the present invention is not limited thereto.

[6] Solvent (component (F))
In the preparation of the photosensitive composition of the present invention, the above components are dissolved in a predetermined solvent. Examples of the solvent that can be used in preparing the positive resist composition of the present invention include alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate ester, alkyl alkoxypropionate, cyclic lactone ( Preferable examples include organic solvents such as carbon number 4 to 10), monoketone compounds which may contain a ring (preferably 4 to 10 carbon atoms), alkylene carbonate, alkyl alkoxyacetate, and alkyl pyruvate.

  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.

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

  Such a phenol compound having a molecular weight of 1000 or less is disclosed in, for example, JP-A-4-1222938, JP-A-2-28531, US Pat. No. 4,916,210, European Patent 219294, and the like. It can be easily synthesized by those skilled in the art with reference to the method described.

  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 formation method]
The positive photosensitive 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 photosensitive 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 photosensitive 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 photosensitive 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 applying the solution on a predetermined support as follows. The filter used for filter filtration is preferably made of polytetrafluoroethylene, polyethylene, or nylon having a pore size of 0.1 μm or less, more preferably 0.05 μm or less, and still more preferably 0.03 μm or less.

For example, a positive photosensitive composition is applied onto a substrate (eg, silicon / silicon dioxide coating) used for the manufacture of precision integrated circuit elements by a suitable application 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 having 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, F ₂ Excimer laser, EUV (13 nm), and electron beam are preferable.

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, etc. may be used. it can.

In the development step, an alkaline developer is used as follows. Examples of the alkaline developer of the positive photosensitive composition include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia and other inorganic alkalis, ethylamine, n-propylamine and the like. Secondary amines such as amines, diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxy Alkaline aqueous solutions such as quaternary ammonium salts such as pyrrole and cyclic amines 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.

  Exposure (immersion exposure) may be performed by filling a liquid (immersion medium) having a higher refractive index than air between the resist film and the lens during irradiation with actinic rays or radiation. 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 photosensitive composition of the present invention is exposed through an immersion medium, 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 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 photosensitive 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 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. The divalent linking group may be selected from the group consisting of 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, or a group 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 a silicon atom 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 group having 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 hydrophobic resin (HR). %.
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, based on all repeating units in the hydrophobic resin (HR). %, More preferably 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 a lactone structure exemplified for the resin of the component (B).

In the hydrophobic resin (HR), examples of the repeating unit having a group (z) that is decomposed by the action of an acid are the same as the repeating unit having an acid-decomposable group listed for the resin (A). In the hydrophobic resin (HR), the content of the repeating unit having a group (z) that decomposes by the action of an acid is preferably 1 to 80 mol% with respect to all the repeating units in the hydrophobic resin (HR). More preferably, it is 10-80 mol%, More preferably, it is 20-60 mol%.
The hydrophobic resin (HR) may further have a repeating unit represented by the following general formula (V).

In general formula (V),
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.

  As in the case of the resin (A), the hydrophobic resin (HR) preferably has 0 to 10% by mass of residual monomer and oligomer components, and more preferably has few impurities such as metals. 0-5 mass% and 0-1 mass% are 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 photosensitive composition of the present invention. Thereby, the generation of particles during storage 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 2 below shows the molar ratio of the 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.

  In order to prevent the resist film from coming into direct contact with the immersion liquid between the resist film made of the positive photosensitive composition of the present invention and the immersion liquid, an immersion liquid hardly soluble film (hereinafter referred to as “topcoat”) is also used. 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 include polymers and fluorine-containing polymers. 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 viewpoint, 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 photosensitive 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 still in detail, the content of this invention is not limited by this.
(1) Synthesis Example 1 (Synthesis of Resin (1))
Under a nitrogen stream, 42 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. 9.40 g, 2.40 g, 3.46, 4.76 g, 1.60 g, polymerization initiator V601 (manufactured by Wako Pure Chemicals, 1.56 g, 10 mol% based on monomer) were added to the following compounds in order from the left. A solution dissolved in 80 g was added dropwise over 6 hours. After completion of dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction solution was allowed to cool and then added dropwise to a mixture of 800 ml of hexane / 300 ml of ethyl acetate over 20 minutes, and the precipitated powder was collected by filtration and dried to obtain Resin (1) (13.2 g). The weight average molecular weight of the obtained resin (1) was 8390 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.59.

Resins (2) to (19) as resins (A) of the present invention and resins Q1 and Q2 for comparison were synthesized in the same manner as in Synthesis Example 1. The structure of each synthesized resin is shown below. Table 3 below shows the molar ratio of repeating units in each resin (corresponding to each repeating unit in the structural formula in order from the left), the weight average molecular weight Mw, the degree of dispersion Pd, and the van der Waals volume of the acid-decomposable group. .

Examples 1-2 , Reference Examples 1-19 and Comparative Examples 1-2
<Preparation of resist composition>
The components shown in Tables 4-1 and 4-2 below are dissolved in a solvent, and a solution with a solid content concentration of 5% by mass is prepared for each, and this is filtered through a polyethylene filter having a pore size of 0.1 μm to form a positive resist. A composition was prepared. The prepared positive resist composition was exposed according to the following exposure condition (1) or exposure condition (2), and the resulting resist pattern was evaluated by the following method. The results are shown in Table 5. About each component in Table 4-1, the ratio at the time of using multiple is a mass ratio.

  In Table 4-2, when the positive resist composition contains a hydrophobic resin (HR), the addition form is marked as “addition”. When the positive resist composition does not contain a hydrophobic resin (HR) and a topcoat protective film containing a hydrophobic resin (HR) is formed on the upper layer after forming a resist film, the addition form is “ TC ".

(Exposure conditions (1) ArF dry exposure)
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 130 ° C. for 60 seconds to form a 120 nm resist film. Using the obtained wafer ArF excimer laser scanner (manufactured by ASML, PAS5500 / 1100, NA0.75), exposure was performed through a 6% halftone mask of 75 nm 1: 1 line and space pattern. Thereafter, heating was performed at 130 ° 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.

(Exposure condition (2) ArF immersion exposure)
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 130 ° C. for 60 seconds to form a 120 nm resist film. The obtained wafer was exposed through a 6% halftone mask of 65 nm 1: 1 line and space pattern using an ArF excimer laser immersion scanner (XT1250i, manufactured by ASML, NA 0.85). Ultra pure water was used as the immersion liquid. Thereafter, heating was performed at 130 ° 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.

  When the addition form of the hydrophobic resin (HR) was “TC”, the following operation was performed after forming the resist film.

<Formation method of top coat>
The hydrophobic resin (HR) shown in Table 4-2 was dissolved in a solvent on the resist film, applied by a spin coater, and the wafer was heated and dried at 115 ° C. for 60 seconds to form a 0.05 μm top coat layer. . At this time, the top coat application unevenness was observed, and it was confirmed that it was uniformly applied without application unevenness.

  Abbreviations for solvents are as follows.

SL-6: Perfluorobutyltetrahydrofuran [Line edge roughness]
The line edge roughness (LER) is measured by using a length-measuring scanning electron microscope (SEM) to observe an isolated pattern of 120 nm, and the longitudinal edge of the line pattern from the reference line where the edge should be in the range of 5 μm. The distance was measured by 50 points using a length measuring SEM (Hitachi, Ltd. S-8840), the standard deviation was obtained, and 3σ was calculated. A smaller value indicates better performance.

[Exposure latitude]
The exposure amount that reproduces a line-and-space mask pattern with a line width of 0.13 μm is set as the optimal exposure amount, and when the exposure amount is changed, an exposure amount width that allows a pattern size of 0.13 μm ± 10% is obtained. The value was divided by the optimum exposure and displayed as a percentage. The larger the value, the smaller the change in performance due to the change in exposure amount, and the better the exposure latitude (EL).

  The abbreviations in Tables 4-1 and 4-2 are as follows.

Basic compound N-1: Trioctylamine N-2: 2,6-diisopropylaniline N-3: N-phenyldiethanolamine N-4: Diazabicyclo [4.3.0] nonene N-5: Dicyclohexylmethylamine N- 6: 2,4,5-triphenylimidazole Surfactant W-1: Megafac F176 (manufactured by Dainippon Ink & Chemicals, Inc.) (fluorine type)
W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicon)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) (silicon-based)
Dissolution inhibiting compound D-1: t-butyl lithocholic acid organic solvent SL-1: propylene glycol monomethyl ether acetate SL-2: cyclohexanone SL-4: propylene glycol monomethyl ether SL-5: ethyl lactate

  From the results in Table 5, the positive photosensitive composition of the present invention provides a pattern having excellent line edge roughness and excellent exposure latitude not only in normal exposure (dry exposure) but also in immersion exposure. I knew it was possible.

Claims (4)

(A) A repeating unit represented by the general formula (I) and a repeating unit represented by the general formula (II) that generate a carboxylic acid by the action of an acid, and a repeating unit represented by the general formula (IV) tree with butter,
(B) a compound that generates an acid upon irradiation with an actinic ray or radiation , and
(C) A positive photosensitive composition comprising a hydrophobic resin .

In general formula (I),
R ₁ , R ₂ and R ₃ each independently represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted cycloalkyl group. R ₂ and R ₃ may be bonded to each other to form a ring structure.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group.
The van der Waals volume of the structure represented by the general formula (I) is 306 × 10 ⁻³⁰ m ³ or less.

In general formula (II),
R ₄ is to display the hydrocarbon group having 20 or less carbon atoms, which may have a substituent.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group.
n represents an integer of 0 to 5.

In general formula (IV),
R ₆ represents a hydrocarbon group having at least one cyclic structure and having neither a hydroxyl group nor a cyano group.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group.   The positive photosensitive composition according to claim 1, wherein the resin (A) further has a repeating unit containing a lactone group. The positive photosensitive composition according to claim 1 or 2, wherein the resin (A) further has a repeating unit represented by the general formula (III).

In general formula (III),
R ₅ represents an alicyclic hydrocarbon structure having a hydroxyl group or a cyano group.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group. Using a positive photosensitive composition according to any one of claims 1 to 3 to form a film, exposing the film pattern forming method, which comprises a step of developing.