JP2006347891A - Polyhydric phenol compound, compound, positive resist composition and method for forming resist pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition capable of forming a resist pattern reduced in roughness and to provide a resist pattern-forming method and to provide a compound suitable for the positive resist composition, and a polyhydric phenol compound suitable as a raw material for the compound. <P>SOLUTION: The present invention provides the polyhydric phenol compound represented by formula (I) [wherein R<SB>11</SB>to R<SB>12</SB>are each independently a 3-10C branched alkyl group] and having 300-2,500 molecular weight, the compound in which a part or all of hydrogen atom of a phenolic hydroxy group in the polyhydric phenol compound is substituted with an acid-dissociable dissolution-suppressing group, and the positive resist composition containing the compound. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a positive resist composition, a compound suitable for the positive resist composition, a polyhydric phenol compound suitable as a raw material for the compound, and a resist pattern forming method using the positive resist composition.

In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization has been rapidly progressing due to advances in lithography technology.
As a technique for miniaturization, the wavelength of an exposure light source is generally shortened. Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but at present, mass production of semiconductor elements using a KrF excimer laser or an ArF excimer laser has started. In addition, studies have been made on F ₂ excimer lasers, electron beams, EUV (extreme ultraviolet rays), X-rays, and the like having shorter wavelengths than these excimer lasers.
Further, as one of pattern forming materials capable of forming a pattern with fine dimensions, a chemically amplified resist containing a base material component having a film forming ability and an acid generator component that generates an acid upon exposure is known. ing. Chemically amplified resists include a negative type in which alkali solubility is reduced by exposure and a positive type in which alkali solubility is increased by exposure.

Conventionally, a polymer has been used as a base material component of such a chemically amplified resist. For example, a PHS system such as polyhydroxystyrene (PHS) or a resin in which a part of its hydroxyl group is protected with an acid dissociable, dissolution inhibiting group. Resins, copolymers derived from (meth) acrylic acid esters, resins in which a part of the carboxy group is protected with an acid dissociable, dissolution inhibiting group, and the like are used.
However, when a pattern is formed using such a pattern forming material, there is a problem that roughness is generated on the upper surface of the pattern or the surface of the side wall. For example, the roughness of the resist pattern side wall surface, that is, the line edge roughness (LER) causes distortion around the hole in the hole pattern, variation in the line width in the line and space pattern, and the like. May cause adverse effects.
Such a problem becomes more serious as the pattern size is smaller. Therefore, for example, lithography using electron beams or EUV aims to form a fine pattern of several tens of nanometers, and therefore extremely low roughness exceeding the current pattern roughness is required.
However, a polymer generally used as a substrate has a large molecular size (average square radius per molecule) of around several nm. In the development process of pattern formation, the dissolution behavior of the resist with respect to the developing solution is usually performed in units of one molecular component of the base material. Therefore, as long as a polymer is used as the base material component, further reduction in roughness is extremely difficult.

In order to solve such a problem, a resist using a low molecular material as a base material component has been proposed as a material aiming for extremely low roughness. For example, Patent Documents 1 and 2 propose low molecular weight materials having an alkali-soluble group such as a hydroxyl group, and part or all of which is protected with an acid dissociable, dissolution inhibiting group. Such a low molecular weight material is expected to be able to reduce roughness because of its low molecular weight, thus having a small molecular size.
JP 2002-099088 A JP 2002-099089 A

However, it is difficult to form a resist pattern with reduced roughness using such a material, for example, a pattern finer than 90 nm at a practically usable level. For example, there is a problem that the pattern itself cannot be formed (pattern formation ability is low), and even if the pattern can be formed, the roughness is not sufficiently reduced or the shape cannot be sufficiently retained (pattern retention ability is low). There is a problem.
The present invention has been made in view of the above circumstances, and is a positive resist composition capable of forming a resist pattern with reduced roughness, a resist pattern forming method, a compound suitable for the positive resist composition, and An object is to provide a polyhydric phenol compound suitable as a raw material for the compound.

As a result of intensive studies, the present inventors have found that the above problems can be solved by a polyphenol compound having a specific structure and molecular weight, and have completed the present invention.
That is, the 1st aspect of this invention is a polyhydric phenol compound represented by the following general formula (I) and whose molecular weight is 300-2500.

［式（Ｉ）中、Ｒ_１１〜Ｒ_１２はそれぞれ独立に炭素数３〜１０の分岐状のアルキル基であり；Ｒ_１３〜Ｒ_１４はそれぞれ独立に炭素数１〜５の直鎖または分岐状のアルキル基であり；ｌ、ｎはそれぞれ独立に０または１であり；Ｘは下記一般式（Ｉａ）または（Ｉｂ）で表される基である。］

[In Formula (I), R _{11 to} R ₁₂ are each independently a branched alkyl group having 3 to 10 carbon atoms; R _{13 to} R ₁₄ are each independently a linear or branched group having 1 to 5 carbon atoms; 1 and n are each independently 0 or 1, and X is a group represented by the following general formula (Ia) or (Ib). ]

［式（Ｉａ）中、Ｒ_１８〜Ｒ_１９はそれぞれ独立に炭素数１〜１０のアルキル基または芳香族炭化水素基であって、その構造中にヘテロ原子を含んでもよく；ｒ、ｙ、ｚはそれぞれ独立に０または１以上の整数であり、かつｒ＋ｙ＋ｚが４以下である。］

[In formula (Ia), R _{18 to} R ₁₉ each independently represents an alkyl group having 1 to 10 carbon atoms or an aromatic hydrocarbon group, and may contain a hetero atom in the structure thereof; r, y, z Are each independently an integer of 0 or 1 and r + y + z is 4 or less. ]

  The second aspect of the present invention is represented by the following general formula (I), and part or all of the hydrogen atoms of the phenolic hydroxyl group in the polyhydric phenol compound having a molecular weight of 300 to 2500 are acid dissociable, dissolution inhibiting groups. It is a substituted compound.

［式（Ｉ）中、Ｒ_１１〜Ｒ_１２はそれぞれ独立に炭素数３〜１０の分岐状のアルキル基であり；Ｒ_１３〜Ｒ_１４はそれぞれ独立に炭素数１〜５の直鎖または分岐状のアルキル基であり；ｌ、ｎはそれぞれ独立に０または１であり；Ｘは下記一般式（Ｉａ）または（Ｉｂ）で表される基である。］

[In Formula (I), R _{11 to} R ₁₂ are each independently a branched alkyl group having 3 to 10 carbon atoms; R _{13 to} R ₁₄ are each independently a linear or branched group having 1 to 5 carbon atoms; 1 and n are each independently 0 or 1, and X is a group represented by the following general formula (Ia) or (Ib). ]

［式（Ｉａ）中、Ｒ_１８〜Ｒ_１９はそれぞれ独立に炭素数１〜１０のアルキル基または芳香族炭化水素基であって、その構造中にヘテロ原子を含んでもよく；ｒ、ｙ、ｚはそれぞれ独立に０または１以上の整数であり、かつｒ＋ｙ＋ｚが４以下である。］

[In formula (Ia), R _{18 to} R ₁₉ each independently represents an alkyl group having 1 to 10 carbon atoms or an aromatic hydrocarbon group, and may contain a hetero atom in the structure thereof; r, y, z Are each independently an integer of 0 or 1 and r + y + z is 4 or less. ]

A third aspect of the present invention is a positive resist composition containing a base component (A) whose alkali solubility is increased by the action of an acid and an acid generator component (B) that generates an acid upon exposure. There,
The base component (A) is represented by the following general formula (I), and part or all of the hydrogen atoms of the phenolic hydroxyl group in the polyhydric phenol compound having a molecular weight of 300 to 2500 are acid dissociable, dissolution inhibiting groups. A positive resist composition comprising a substituted compound (A1).

［式（Ｉ）中、Ｒ_１１〜Ｒ_１２はそれぞれ独立に炭素数３〜１０の分岐状のアルキル基であり；Ｒ_１３〜Ｒ_１４はそれぞれ独立に炭素数１〜５の直鎖または分岐状のアルキル基であり；ｌ、ｎはそれぞれ独立に０または１であり；Ｘは下記一般式（Ｉａ）または（Ｉｂ）で表される基である。］

[In Formula (I), R _{11 to} R ₁₂ are each independently a branched alkyl group having 3 to 10 carbon atoms; R _{13 to} R ₁₄ are each independently a linear or branched group having 1 to 5 carbon atoms; 1 and n are each independently 0 or 1, and X is a group represented by the following general formula (Ia) or (Ib). ]

［式（Ｉａ）中、Ｒ_１８〜Ｒ_１９はそれぞれ独立に炭素数１〜１０のアルキル基または芳香族炭化水素基であって、その構造中にヘテロ原子を含んでもよく；ｒ、ｙ、ｚはそれぞれ独立に０または１以上の整数であり、かつｒ＋ｙ＋ｚが４以下である。］

[In formula (Ia), R _{18 to} R ₁₉ each independently represents an alkyl group having 1 to 10 carbon atoms or an aromatic hydrocarbon group, and may contain a hetero atom in the structure thereof; r, y, z Are each independently an integer of 0 or 1 and r + y + z is 4 or less. ]

  According to a fourth aspect of the present invention, there is provided a step of forming a resist film on a substrate using the positive resist composition of the third aspect, a step of exposing the resist film, and developing the resist film to form a resist pattern It is a resist pattern formation method including the process of forming.

Here, unless otherwise specified, the “alkyl group” in the claims and the specification means a monovalent saturated hydrocarbon group.
“Exposure” is a concept that includes general irradiation of radiation.

  According to the present invention, there are provided a positive resist composition and a resist pattern forming method capable of forming a resist pattern with reduced roughness, a compound suitable for the positive resist composition, and a polyhydric phenol compound suitable as a raw material for the compound. Provided.

≪Polyhydric phenol compound≫
The polyhydric phenol compound of the present invention is a polyhydric phenol compound represented by the above general formula (I) and having a molecular weight of 300 to 2500 (hereinafter referred to as polyhydric phenol compound (I)).

In the general formula (I), R _{11 to} R ₁₂ are each independently a branched alkyl group having 3 to 10 carbon atoms, preferably a lower alkyl group having 3 to 5 carbon atoms. Examples of the branched alkyl group represented by R _{11 to} R ₁₂ include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, and a neopentyl group. Among these, an isopropyl group is preferable.
R _{13 to} R ₁₄ are each independently a linear or branched alkyl group having 1 to 5 carbon atoms. Examples of the linear alkyl group represented by R _{13 to} R ₁₄ include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-propyl group. Examples of the branched alkyl group of R _{13 to} R ₁₄ include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, and a neopentyl group.
l and n are each independently 0 or 1, preferably 0.

X is a group represented by the above general formula (Ia) or (Ib).
In formula (Ia), R _{18 to} R ₁₉ each independently represent a linear, branched or cyclic alkyl group or aromatic hydrocarbon group having 1 to 10 carbon atoms. The alkyl group or aromatic hydrocarbon group may contain a hetero atom such as an oxygen atom, a nitrogen atom, or a sulfur atom in the structure.
The linear or branched alkyl group of R _{18 to} R ₁₉ preferably has 1 to 5 carbon atoms, and the alkyl group is the same as the linear or branched alkyl group of R _{13 to} R ₁₄ . Things.
The cyclic alkyl group of R _{18 to} R ₁₉ preferably has 5 to 6 carbon atoms, and examples thereof include a cyclopentyl group and a cyclohexyl group.
Examples of the aromatic hydrocarbon group include a phenyl group, a tolyl group, a xylyl group, a mesityl group, a phenethyl group, and a naphthyl group.
r, y, and z are each independently 0 or an integer of 1 or more, and r + y + z is 4 or less.
X is most preferably a group represented by the general formula (Ib) from the viewpoint of easy synthesis.

  In the present invention, the polyphenol compound (I) needs to have a molecular weight of 300 to 2500, preferably 450 to 1500, and more preferably 500 to 1200. When the molecular weight is within the above range, roughness can be reduced and a pattern with excellent resolution can be formed. Further, the profile shape of the resist pattern is good.

The polyhydric phenol compound (I) preferably has a molecular weight dispersity (Mw / Mn) of 1.5 or less because the effects of the present invention are further excellent. This is because the polyhydric phenol compound (I) has a narrow molecular weight distribution with a dispersity of 1.5 or less, so that the compound (A1) in the polyhydric phenol compound (I) is included in the positive resist composition. It is considered that the alkali solubility of each compound is relatively uniform even if multiple compounds with different numbers (protection numbers) of the hydrogen atom of the phenolic hydroxyl group substituted with an acid dissociable, dissolution inhibiting group are included. It is done. The degree of dispersion is preferably as small as possible, more preferably 1.4 or less, and most preferably 1.3 or less.
Here, “dispersion degree” is usually used for polydisperse compounds such as polymers, but even if it is a monodisperse compound, impurities such as by-products during production and residual starting materials Due to the presence of this, when analyzed by gel permeation chromatography (GPC) or the like, a distribution may appear in its molecular weight. That is, in the case of a monodispersed compound, a degree of dispersion of 1 means that the purity is 100%, and the greater the degree of dispersion, the greater the amount of impurities. In the present invention, the degree of dispersion is a method for measuring a mass average molecular weight (Mw) and a number average molecular weight (Mn) of a polymer that is generally used for a compound showing such an apparent molecular weight distribution, such as GPC. Can be calculated by measuring Mw and Mn and determining the Mw / Mn ratio.
The degree of dispersion is determined by synthesizing the polyphenol compound (I), which is the final target product, and then purifying and removing reaction by-products and impurities, or removing unnecessary molecular weight parts by known methods such as molecular weight fractionation. Can be adjusted.

The polyhydric phenol compound (I) is a material capable of forming an amorphous film by a spin coating method in a state where no hydrogen atom of the hydroxyl group is substituted with an acid dissociable, dissolution inhibiting group.
Here, the spin coating method is one of commonly used thin film forming methods, and an amorphous film means an optically transparent film that does not crystallize.
Whether or not the polyhydric phenol compound is a material capable of forming an amorphous film by the spin coating method can be determined by whether or not the coating film formed by the spin coating method on the 8-inch silicon wafer is entirely transparent. More specifically, for example, the determination can be made as follows. First, for the polyhydric phenol compound, a solvent generally used as a resist solvent is used, for example, a mixed solvent of ethyl lactate / propylene glycol monomethyl ether acetate = 40/60 (mass ratio) (hereinafter abbreviated as EM). Is dissolved by applying ultrasonic treatment (dissolution treatment) using an ultrasonic cleaner, and the solution is spin-coated on the wafer at 1500 rpm. Is subjected to dry baking (PAB, Post Applied Bake) at 110 ° C. for 90 seconds, and in this state, it is visually determined whether a transparent film has been obtained, whereby an amorphous film is formed. Check if it is. A cloudy film that is not transparent is not an amorphous film.
Further, the polyphenol compound (I) preferably has an amorphous film formed as described above having good stability. For example, after the PAB, the polyphenol compound (I) is allowed to stand at room temperature for 2 weeks. It is preferable that a transparent state, that is, an amorphous state is maintained.

  The polyhydric phenol compound (I) includes, for example, a bissalicylaldehyde derivative (for example, methylenebissalicylaldehyde) in which two salicylaldehydes (which may have a substituent) are bonded to X, and the bissalicylaldehyde About 4 equivalents of a 2,6-substituted phenol (phenol having a branched alkyl group having 3 to 10 carbon atoms bonded to the 2nd and 6th positions; for example, 2,6-diisopropylphenol) dissolved in an organic solvent. Then, it can be synthesized by reacting under acidic conditions.

≪Compound≫
In the compound of the present invention (hereinafter referred to as compound (A1)), part or all of the hydrogen atoms of the phenolic hydroxyl group in the polyhydric phenol compound (I) are substituted with acid dissociable, dissolution inhibiting groups. A compound.
The acid dissociation / dissolution-inhibiting group is a group that has an alkali dissolution inhibiting property that makes the entire compound (A1) insoluble in alkali before dissociation and changes the entire compound (A1) to alkali-soluble after dissociation. Therefore, in the compound (A1), when it is blended with the (B) component in the positive resist composition, when the acid generated from the (B) component acts upon exposure, the acid dissociation and dissolution inhibiting group is dissociated, The entire compound (A1) changes from alkali-insoluble to alkali-soluble.

The acid dissociable, dissolution inhibiting group is not particularly limited, and is appropriately selected from among those proposed for hydroxystyrene resins, (meth) acrylic acid resins and the like used in chemically amplified resist compositions for KrF and ArF. It can be selected and used. Specific examples include a tertiary alkyl group, a tertiary alkyloxycarbonyl group, an alkoxycarbonylalkyl group, an alkoxyalkyl group, and a cyclic ether group.
Specific examples of the tertiary alkyl group include chain-like tertiary alkyl groups such as tert-butyl group and tert-amyl group, 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group and the like. And tertiary alkyl groups containing an aliphatic polycyclic group.
Here, “aliphatic” in the claims and the specification is a relative concept with respect to aromatics, and is defined to mean a group, a compound, or the like that does not have aromaticity. The “aliphatic cyclic group” means a monocyclic group or polycyclic group having no aromaticity.
Examples of the tertiary alkyl group in the tertiary alkyloxycarbonyl group include those described above. Specific examples of the tertiary alkyloxycarbonyl group include a tert-butyloxycarbonyl group and a tert-amyloxycarbonyl group.
Specific examples of the cyclic ether group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  In the present invention, since it is particularly excellent in the effects of the present invention, it is selected from the group consisting of an alkoxycarbonylalkyl group represented by the following general formula (p1) and an alkoxyalkyl group represented by the following general formula (p2). It is preferable to have at least one acid dissociable, dissolution inhibiting group.

［式中、Ｒ^１およびＲ^２はそれぞれ独立に直鎖状、分岐状または環状のアルキル基であって、その構造中にヘテロ原子を含んでもよく；Ｒ^３は水素原子または低級アルキル基であり；ｎ’は１〜３の整数である。］

[Wherein R ¹ and R ² are each independently a linear, branched or cyclic alkyl group and may contain a heteroatom in the structure; R ³ is a hydrogen atom or a lower alkyl group; N ′ is an integer of 1 to 3; ]

  In the general formula (p1), n ′ is an integer of 1 to 3, and is preferably 1.

R ¹ is a linear, branched or cyclic alkyl group and may contain a hetero atom in its structure. That is, in the alkyl group as R ¹ , part or all of the hydrogen atoms may be substituted with a group containing a hetero atom (including the case of the hetero atom itself), and a part of the carbon atoms of the alkyl group may be substituted. It may be substituted with a heteroatom.
Examples of the hetero atom include an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom.
The group containing a heteroatom may be a heteroatom itself, or may be a group comprising a heteroatom and a carbon atom and / or a hydrogen atom, such as an alkoxy group.
Examples of alkyl groups in which some or all of the hydrogen atoms are substituted with groups containing heteroatoms include, for example, fluorinated lower alkyls having 1 to 5 carbon atoms in which some or all of the hydrogen atoms are substituted with fluorine atoms A group in which two hydrogen atoms bonded to the same carbon atom are substituted with one oxygen atom (that is, a group having a carbonyl group (C═O)), two hydrogen atoms bonded to the same carbon atom are 1 And a group substituted with two sulfur atoms (that is, a group having thiocarbonyl (C = S)).
Examples of the group in which a part of the carbon atoms of the alkyl group is substituted with a group containing a hetero atom include, for example, an example in which the carbon atom is substituted with a nitrogen atom (for example, a branch containing —CH ₂ — in the structure thereof) A group in which the —CH ₂ — is substituted with —NH— in a chain-like or cyclic alkyl group) or examples in which a carbon atom is substituted with an oxygen atom (for example, a branched structure containing —CH ₂ — in its structure) Or a group in which the —CH ₂ — is substituted with —O— in a cyclic alkyl group).

The linear alkyl group as R ¹ preferably has 1 to 5 carbon atoms, and specifically includes a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isobutyl group, and an n-pentyl group. Group, and is preferably a methyl group or an ethyl group.
The branched alkyl group as R ¹ preferably has 4 to 10 carbon atoms, and more preferably 4 to 8 carbon atoms. Specific examples include an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, and a tert-pentyl group, and a tert-butyl group is preferable.

The cyclic alkyl group as R ¹ preferably has 3 to 20 carbon atoms, more preferably 4 to 14 carbon atoms, and most preferably 5 to 12 carbon atoms.
The structure of the basic ring (basic ring excluding the substituent) in the cyclic alkyl group may be monocyclic or polycyclic, and is particularly preferably polycyclic because it is excellent in the effects of the present invention. The basic ring may be a hydrocarbon ring composed of carbon and hydrogen, or may be a heterocycle in which a part of carbon atoms constituting the hydrocarbon ring is substituted with a heteroatom. In the present invention, the basic ring is particularly preferably a hydrocarbon ring. Specific examples of the hydrocarbon ring include monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these, adamantane, norbornane, tricyclodecane, and tetracyclododecane are preferable, and adamantane is particularly preferable.
These basic rings may or may not have a substituent on the ring. Examples of the substituent include a lower alkyl group, a fluorine atom, a fluorinated lower alkyl group, and an oxygen atom (═O). Examples of the lower alkyl group include linear or branched alkyl groups having 1 to 5 carbon atoms such as a methyl group and an ethyl group. When the basic ring has a substituent, the number of substituents is preferably 1 to 3, and more preferably 1. Here, “having a substituent” means that a hydrogen atom bonded to a carbon atom constituting the basic ring is substituted with a substituent.
Examples of the cyclic alkyl group for R ¹ include groups in which one hydrogen atom has been removed from these basic rings. In R ¹ , the carbon atom to which the oxygen atom adjacent to R ¹ is bonded is preferably one of the carbon atoms constituting the basic ring as described above, and in particular, to the oxygen atom adjacent to R ¹ The carbon atom to be bonded is preferably a tertiary carbon atom to which a substituent such as a lower alkyl group is bonded, since the effect of the present invention is excellent.
Examples of the acid dissociable, dissolution inhibiting group having such a cyclic alkyl group as R ¹ include groups represented by the following formulas.

［式中、Ｒ^４は低級アルキル基であり、ｎ’は上記と同様である。］

[Wherein, R ⁴ is a lower alkyl group, and n ′ is the same as described above. ]

  Among these, what is represented by the following general formula is preferable.

［式中、Ｒ^４は低級アルキル基であり、ｎ’は上記と同様である。］

[Wherein, R ⁴ is a lower alkyl group, and n ′ is the same as described above. ]

The lower alkyl group for R ^{4 is} an alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, Examples include lower linear or branched alkyl groups such as a pentyl group, isopentyl group, and neopentyl group. R ⁴ is preferably a methyl group or an ethyl group, and more preferably a methyl group in terms of industrial availability.

In formula (p2), examples of R ² include the same groups as those described above for R ¹ . Among them, R ² is preferably a linear alkyl group or a cyclic alkyl group.
R ³ is a hydrogen atom or a lower alkyl group. The lower alkyl group for R ^{3 is} an alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, Examples include lower linear or branched alkyl groups such as a pentyl group, isopentyl group, and neopentyl group. R ³ is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom, in terms of industrial availability.

Examples of the group represented by the formula (p2) in which R ² is a linear alkyl group include 1-ethoxyethyl group, 1-ethoxymethyl group, 1-methoxyethyl group, 1-methoxymethyl group, 1-methoxymethyl group, Examples include methoxypropyl group, 1-ethoxypropyl group, 1-n-butoxyethyl group, 1-pentafluoroethoxyethyl group, 1-trifluoromethoxyethyl group, 1-trifluoromethoxymethyl group and the like.
Examples of the group represented by the formula (p2) in which R ² is a cyclic alkyl group include groups represented by the following formulas.

［式中、Ｒ^３は前記と同じである。］

[Wherein R ³ is the same as defined above. ]

  As the group represented by the formula (p2), a compound represented by the following general formula is particularly preferable.

［式中、Ｒ^３は前記と同じであり、ｎ’’は０または１〜２の整数であり、Ｗは２原子の水素原子または酸素原子である。］

[Wherein R ³ is the same as defined above, n ″ is 0 or an integer of 1 to 2, and W is a hydrogen atom or an oxygen atom of 2 atoms. ]

n ″ is most preferably 0 or 1.
The bonding position between the adamantyl group and —CH (R ³ ) —O— (CH ₂ ) _{n ″} — is not particularly limited, but is preferably bonded to the 1-position or 2-position of the adamantyl group.

  In the compound (A1), the protection ratio (mol%) of the phenolic hydroxyl group in the compound (A1), that is, “the total amount of the phenolic hydroxyl group protected by the acid dissociable, dissolution inhibiting group and the unprotected phenolic hydroxyl group The ratio (mol%) of “phenolic hydroxyl group protected with an acid dissociable, dissolution inhibiting group” in consideration of the structure of the polyhydric phenol compound (I), the number of phenolic hydroxyl groups, various desired lithographic properties, etc. Can be determined as appropriate. For example, considering the resolution and roughness reduction effect, 5 to 70 mol% is preferable, 10 to 65 mol% is more preferable, 20 to 60 mol% is further preferable, and 30 to 60 mol% is most preferable.

  Compound (A1) can be produced, for example, by substituting part or all of the hydrogen atoms of the phenolic hydroxyl group of polyhydric phenol compound (I) with an acid dissociable, dissolution inhibiting group by a known method.

≪Positive resist composition≫
The positive resist composition of the present invention has a base component (A) (hereinafter sometimes referred to as component (A)) having an acid dissociable, dissolution inhibiting group and increasing alkali solubility by the action of an acid; And an acid generator component (B) that generates an acid upon exposure (hereinafter also referred to as component (B)).
In the component (A), when an acid generated from the component (B) acts upon exposure, the acid dissociable, dissolution inhibiting group is dissociated, thereby changing the entire component (A) from alkali-insoluble to alkali-soluble. Therefore, in the formation of the resist pattern, when the resist film made of the resist composition is selectively exposed or heated after exposure in addition to the exposure, the exposed portion turns to alkali-soluble while the unexposed portion remains alkali-insoluble. Since it does not change, a positive resist pattern can be formed by alkali development.

In the positive resist composition of the present invention, the component (A) needs to contain the compound (A1) of the present invention.
A compound (A1) may be used individually by 1 type, and may use 2 or more types together.
In the component (A), the proportion of the compound (A1) is preferably more than 40% by mass, more preferably more than 50% by mass, further preferably more than 80% by mass, and most preferably 100% by mass. is there.
The proportion of compound (A1) in component (A) can be measured by means such as reverse phase chromatography.

The component (A) may further contain any resin component that has been proposed as a base material component of the chemically amplified resist layer so far as the effects of the present invention are not impaired.
Examples of such resin components include those proposed as base resins for conventional chemically amplified KrF positive resist compositions, ArF positive resist compositions, and the like. It can be appropriately selected according to the type.

  In the positive resist composition of the present invention, the content of the component (A) may be adjusted according to the resist film thickness to be formed.

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

  Examples of the onium salt acid generator include compounds represented by the following general formula (b-1) or (b-2).

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

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

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group. At least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably all R ¹ ″ to R ³ ″ are aryl groups.
The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups It may or may not be substituted with a group, a halogen atom or the like. The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Is most preferred.
The alkoxy group that may be substituted for the hydrogen atom of the aryl group is preferably an alkoxy group having 1 to 5 carbon atoms, and most preferably a methoxy group or an ethoxy group.
The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.
The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, a straight, include alkyl groups such as branched or cyclic. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decanyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.
Among these, it is most preferable that all of R ¹ ″ to R ³ ″ are phenyl groups.

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

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

  Specific examples of the onium salt-based acid generator include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, and triphenylsulfonium trifluoromethane. Sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethane Sulfonate, its heptafluoropropane sulphonate or its Nafluorobutane sulfonate, trifluoromethane sulfonate of monophenyldimethylsulfonium, heptafluoropropane sulfonate or nonafluorobutane sulfonate thereof, trifluoromethane sulfonate of diphenyl monomethylsulfonium, heptafluoropropane sulfonate or nonafluorobutane sulfonate thereof, (4- Trifluoromethanesulfonate of methylphenyl) diphenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of (4-methoxyphenyl) diphenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, tri (4 -Tert-bu E) phenylsulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or nonafluorobutanesulfonate, diphenyl (1- (4-methoxy) naphthyl) sulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or nonafluorobutanesulfonate Is mentioned. In addition, onium salts in which the anion portion of these onium salts is replaced with methanesulfonate, n-propanesulfonate, n-butanesulfonate, or n-octanesulfonate can also be used.

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

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

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

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

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

（式（Ｂ−１）中、Ｒ^２１、Ｒ^２２はそれぞれ独立に有機基を表す。）

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

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

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

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

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

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

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

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

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

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

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

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

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

  Moreover, the example of a preferable compound is shown below among the compounds represented by the said general formula (B-2) or (B-3).

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

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

  In the present invention, it is preferable to use, as the component (B), an onium salt having a fluorinated alkyl sulfonate ion or an alkyl sulfonate ion as an anion.

As the component (B), one type of acid generator may be used alone, or two or more types may be used in combination.
(B) Content of a component is 0.5-30 mass parts with respect to 100 mass parts of (A) component, Preferably it is 1-10 mass parts. By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

[Optional ingredients]
In order to improve the resist pattern shape, the stability over time, etc., the positive resist composition is further mixed with a nitrogen-containing organic compound (D) (hereinafter referred to as (D) component) as an optional component. Can do.
Since a wide variety of components (D) have already been proposed, any known one may be used. For example, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, monoalkylamines such as n-decylamine; dialkylamines such as diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, Tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n- Trialkylamines such as dodecylamine; diethanolamine, trieta Ruamin, diisopropanolamine, triisopropanolamine, di -n- octanol amine, alkyl alcohol amines tri -n- octanol amine is Ageraru. Among these, a secondary aliphatic amine and a tertiary aliphatic amine are particularly preferable, a trialkylamine having 5 to 10 carbon atoms is more preferable, and tri-n-octylamine is most preferable.
These may be used alone or in combination of two or more.
(D) component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

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

  The positive resist composition of the present invention may further contain miscible additives as desired, for example, an additional resin for improving the performance of the resist film, a surfactant for improving coating properties, a dissolution inhibitor, Plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like can be added and contained as appropriate.

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

≪Resist pattern formation method≫
The resist pattern forming method of the present invention includes a step of forming a resist film on a substrate using the positive resist composition of the present invention, a step of exposing the resist film, and developing the resist film to form a resist pattern. Including the step of:
More specifically, for example, a resist pattern can be formed by the following resist pattern forming method. That is, first, the positive resist composition is applied onto a substrate such as a silicon wafer with a spinner or the like, and optionally pre-baked (PAB) to form a resist film. The formed resist film is selectively exposed by, for example, exposure through a mask pattern or drawing by direct irradiation of an electron beam without using a mask pattern, using an exposure apparatus such as an electron beam lithography apparatus or an EUV exposure apparatus. After that, PEB (post-exposure heating) is performed. Subsequently, after developing with an alkali developer, rinsing is performed, and the developer on the substrate and the resist composition dissolved by the developer are washed away and dried to obtain a resist pattern.
These steps can be performed using a known method. The operating conditions and the like are preferably set as appropriate according to the composition and characteristics of the positive resist composition to be used.
The exposure light source is not particularly limited, and is performed using radiation such as ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), electron beam, X-ray, soft X-ray. be able to. In particular, the positive resist composition according to the present invention is effective for electron beams or EUV, particularly electron beams.
In some cases, the post-baking step after alkali development may be included, and an organic or inorganic antireflection film may be provided between the substrate and the resist film.

As described above, according to the compound (A1) of the present invention, the positive resist composition containing the compound (A1), and the resist pattern forming method using the positive resist composition, the resist with reduced roughness A pattern can be formed.
The reason why the roughness is reduced is that the compound (A1) has a structure in which the polyphenolic compound (I) is a basic skeleton and the phenolic hydroxyl group is protected with an acid dissociable, dissolution inhibiting group. It is presumed that the dissolution behavior of the resist film obtained using the positive resist composition containing A1) in the developer becomes more uniform.
That is, the conventional resist using a polymer as a base component, for example, in a spin coating process for forming a resist film, highly hydrophilic molecules, highly hydrophobic molecules are partially localized, As a result, the distribution of various components such as the component (B) in the resist film also varies. In addition, in the polymer, the distribution of the acid dissociable, dissolution inhibiting group and the degree of dissociation tend to be uneven. Therefore, the degree of progress when the dissociation (deprotection reaction) of the acid dissociable dissolution inhibiting group by the generated acid proceeds at the interface between the exposed part and the unexposed part is not uniform, or each group after the deprotection reaction It is considered that the roughness increased due to variations in alkali solubility of molecules of the material component and variations in the dissolution rate of the resist film.
On the other hand, in the present invention, the compound (A1) has little difference in physical and chemical properties (molecular weight, hydrophilicity, polarity, etc.) between the molecules, because the polyphenol compound (I) has the above structure. It is guessed. In particular, the distribution state of the acid dissociable, dissolution inhibiting group is relatively uniform, which is considered to contribute to the improvement of roughness.
That is, the polyhydric phenol compound (I) is centered on one carbon atom, one 2-hydroxyphenyl group optionally having a substituent on the carbon atom, and branched at the 2,6-position. A hexacyclic structure in which a 2-hydroxyphenyl group having a tricyclic structure in which two 4-hydroxyphenyl groups having an alkyl group are bonded to another 2-hydroxyphenyl group having another tricyclic structure is bonded via X. Have. In such a structure, due to steric hindrance, an acid dissociable, dissolution inhibiting group is hardly introduced into the hydroxyl group (outer hydroxyl group) of the 4-hydroxyphenyl group, and thereby the reactivity between the phenolic hydroxyl groups present in the molecule is reduced. It is estimated that the difference is getting smaller. For example, when one or both of the branched alkyl groups are not present on both sides of the hydroxyl group of 4-hydroxyphenyl group, the hydroxyl group of 4-hydroxyphenyl group is 2-hydroxyphenyl which is sterically hindered by di (4-hydroxyphenyl) methyl group. Compared with a phenyl group, an acid dissociable, dissolution inhibiting group is easily introduced. By such a small difference, it is considered that the position where the acid dissociable, dissolution inhibiting group is introduced in the molecule, the deviation of the number, and the variation in the degree of dissociation are reduced. Therefore, in the compound (A1), there is little variation in properties, and the properties of the resist film obtained using the positive resist composition containing the compound (A1) become uniform, and the roughness can be reduced.

Examples of the present invention will be described below, but the scope of the present invention is not limited to these examples.
Synthesis Example 1 (Synthesis of polyhydric phenol compound)
5 g of methylenebissalicylaldehyde (Honshu Chemical Industry Co., Ltd.) and 21.4 g of 2,6-diisopropylphenol are dissolved in 120 g of methanol, 40 g of 35% by mass aqueous hydrochloric acid (HClaq) is added, and the mixture is stirred at 60 ° C. For 3 days.
After completion of the reaction, neutralization with a sodium hydroxide aqueous solution (neutrality confirmed with pH test paper), extraction treatment with water / ethyl acetate = 1: 1 (mass ratio), and the separated ethyl acetate solution in sulfuric acid After drying with sodium, the solution was concentrated under reduced pressure to obtain a polyphenol compound (unpurified).
The polyhydric phenol compound (unpurified) was subjected to silica gel column chromatography under the following conditions to obtain 12 g of a polyhydric phenol compound (1) represented by the following formula (1).
[Silica gel column chromatography conditions]
-Filler: Silica gel (Wacoal gel C100)
・ Column (diameter 9cm, length 40cm)
・ Developing solvent: heptane / ethyl acetate = 3/1 (mass ratio)
¹ H-NMR data of the obtained polyhydric phenol compound (1) are shown below.
¹ H-NMR data (heavy DMSO, internal standard: tetramethylsilane): δ 8.96 s 2H, 7.71 s 4H, 6.55-6.79 m 14H, 5.54 s 2H, 3.22 qq 8H Jfg = 6.5 Hz, 1.03 d 48H Jgf = 6.5 Hz

Synthesis Example 2 (Synthesis of compound)
15 g of the polyphenol compound (1) obtained in Synthesis Example 1 was dissolved in 20 g of tetrahydrofuran (THF), 2.1 g of 60% by mass sodium hydride (NaH) was added, and the mixture was stirred for 10 minutes. 13.88 g of 2-methyladamantane was added, and the mixture was stirred at room temperature (rt) for 10 hours.
After completion of the reaction, extraction was performed with water / ethyl acetate = 1: 1 (mass ratio), and the separated ethyl acetate solution was dried over sodium sulfate and concentrated under reduced pressure to give 15.1 g of the following formula (2). The compound (A) -1 represented by this was obtained.

［式（２）中、Ｒは水素原子または下記式（３）で表される基である。］

[In Formula (2), R is a hydrogen atom or group represented by following formula (3). ]

About compound (A) -1, the result of having analyzed by < ¹ > H-NMR is shown below. From this result, the protection ratio of compound (A) -1 (the ratio (mol%) in which R is a group represented by the above formula (3) in R in the above formula (2)) is 54.6%. Met.
¹ H-NMR data (heavy DMSO, internal standard: tetramethylsilane): δ 8.95-9.06 0.16H m, 7.68-7.85 1.54H m, 6.56-6.99 14H m , 5.52-5.82 2H m, 4.25-4.64 6.55H m, 3.47-3.79 2H m, 3.13-3.32 8H m, 0.70-2.30 103.67H m

Synthesis Example 3 (Synthesis of Compound)
15 g of the polyphenol compound (1) obtained in Synthesis Example 1 is dissolved in 120 g of THF, 1.4 g of 60% by mass sodium hydride (NaH) is added and stirred for 10 minutes, and 2-bromoacetic acid-2-methyladamantane 9 .2 g was added and stirred at room temperature (rt) for 10 hours.
After completion of the reaction, extraction was performed with water / ethyl acetate = 1: 1 (mass ratio), and the separated ethyl acetate solution was dried over sodium sulfate and concentrated under reduced pressure to obtain 14.9 g of the above formula (2). The compound (A) -3 represented by these was obtained.
About compound (A) -3, the result of having analyzed by < ¹ > H-NMR is shown below. From this result, the protection rate of compound (A) -3 (the ratio (mol%) in which R is a group represented by the above formula (3) in R in the above formula (2)) is 35.6%. Met.
¹ H-NMR data (heavy DMSO, internal standard: tetramethylsilane): δ 8.94-9.08 m 0.67H, 7.69-7.87 m 3.19H, 6.53-6.99 m 14H 5.52-5.81 m 2H, 4.25-4.65 m 4.27H, 3.43-3.79 m 2H, 3.13-3.32 m 8H, 0.71-2.31. m 84.31H

Example 1 and Comparative Example 1
Each component shown in Table 1 was mixed and dissolved to obtain a positive resist composition solution.

In Table 1, the numerical value in [] shows a compounding quantity (part by mass).
(A) -2: Resin in which 30.7 mol% of the hydroxyl groups of polyhydroxystyrene (mass average molecular weight (Mw) = 8000, Mw / Mn = 2.65) are protected with 1-ethoxyethyl group (B) -1 : Triphenylsulfonium nonafluorobutanesulfonate (D) -1: Tri-n-octylamine (S) -1: PGMEA / EL = 6/4 (mass ratio) mixed solvent

Subsequently, the following evaluation was performed using the obtained positive resist composition solution. The results are shown in Table 2.
<Surface roughness>
The positive resist composition solution was uniformly applied on an 8-inch silicon substrate subjected to hexamethyldisilazane treatment using a spinner, and baked (PAB) at 110 ° C. for 90 seconds to form a resist film (film thickness) 150 nm) was formed.
With respect to the resist film, an electron beam lithography machine HL-800D (VSB) (manufactured by Hitachi Ltd.) is used, and an exposure amount (μC / cm) at which the film thickness after development becomes about 80% of the initial film thickness at an acceleration voltage of 70 kV. ² ) Draw a large area (about 1 cm square), perform a baking process (PEB) for 90 seconds at the PEB temperature shown in Table 2, and use a 2.38 mass% aqueous solution of TMAH (23 ° C.) for 60 seconds. After developing, it was rinsed with pure water for 30 seconds.
After rinsing, the surface of the resist film was observed with an AFM (atomic force microscope: di NanoScope IV / D5000 manufactured by Veeco Instrument Inc.), and the root mean square surface roughness Rms (nm) per 1 μm square was determined.

As is clear from the above results, the positive resist composition of Example 1 using Compound (A) -1 also had a small surface roughness. Since the surface roughness is small, the roughness (LER) of the pattern sidewall when the resist pattern is formed is also reduced.
On the other hand, Comparative Example 1 using a resin had a very large surface roughness. Therefore, LER is also bad.

Claims (7)

A polyhydric phenol compound represented by the following general formula (I) and having a molecular weight of 300 to 2500.

[In Formula (I), R _{11 to} R ₁₂ are each independently a branched alkyl group having 3 to 10 carbon atoms; R _{13 to} R ₁₄ are each independently a linear or branched group having 1 to 5 carbon atoms; 1 and n are each independently 0 or 1, and X is a group represented by the following general formula (Ia) or (Ib). ]

[In formula (Ia), R _{18 to} R ₁₉ each independently represents an alkyl group having 1 to 10 carbon atoms or an aromatic hydrocarbon group, and may contain a hetero atom in the structure thereof; r, y, z Are each independently an integer of 0 or 1 and r + y + z is 4 or less. ] A compound represented by the following general formula (I), wherein a part or all of hydrogen atoms of a phenolic hydroxyl group in a polyhydric phenol compound having a molecular weight of 300 to 2500 is substituted with an acid dissociable, dissolution inhibiting group.

[In Formula (I), R _{11 to} R ₁₂ are each independently a branched alkyl group having 3 to 10 carbon atoms; R _{13 to} R ₁₄ are each independently a linear or branched group having 1 to 5 carbon atoms; 1 and n are each independently 0 or 1, and X is a group represented by the following general formula (Ia) or (Ib). ]

[In formula (Ia), R _{18 to} R ₁₉ each independently represents an alkyl group having 1 to 10 carbon atoms or an aromatic hydrocarbon group, and may contain a hetero atom in the structure thereof; r, y, z Are each independently an integer of 0 or 1 and r + y + z is 4 or less. ] Claims having at least one acid dissociable, dissolution inhibiting group selected from the group consisting of an alkoxycarbonylalkyl group represented by the following general formula (p1) and an alkoxyalkyl group represented by the following general formula (p2) 2. The compound according to 2.

[Wherein R ¹ and R ² are each independently a linear, branched or cyclic alkyl group and may contain a heteroatom in the structure; R ³ is a hydrogen atom or a lower alkyl group; N ′ is an integer of 1 to 3; ] A positive resist composition comprising a base component (A) whose alkali solubility is increased by the action of an acid, and an acid generator component (B) which generates an acid upon exposure,
The base component (A) is represented by the following general formula (I), and part or all of the hydrogen atoms of the phenolic hydroxyl group in the polyhydric phenol compound having a molecular weight of 300 to 2500 are acid dissociable, dissolution inhibiting groups. A positive resist composition comprising a substituted compound (A1).

[In Formula (I), R _{11 to} R ₁₂ are each independently a branched alkyl group having 3 to 10 carbon atoms; R _{13 to} R ₁₄ are each independently a linear or branched group having 1 to 5 carbon atoms; 1 and n are each independently 0 or 1, and X is a group represented by the following general formula (Ia) or (Ib). ]

[In formula (Ia), R _{18 to} R ₁₉ each independently represents an alkyl group having 1 to 10 carbon atoms or an aromatic hydrocarbon group, and may contain a hetero atom in the structure thereof; r, y, z Are each independently an integer of 0 or 1 and r + y + z is 4 or less. ] The base component (A) is at least one acid selected from the group consisting of an alkoxycarbonylalkyl group represented by the following general formula (p1) and an alkoxyalkyl group represented by the following general formula (p2) The positive resist composition according to claim 4, which has a dissociable, dissolution inhibiting group.

[Wherein R ¹ and R ² are each independently a linear, branched or cyclic alkyl group and may contain a heteroatom in the structure; R ³ is a hydrogen atom or a lower alkyl group; N ′ is an integer of 1 to 3; ]   Furthermore, the positive resist composition of Claim 4 or 5 containing a nitrogen-containing organic compound (D). A step of forming a resist film on a substrate using the positive resist composition according to any one of claims 4 to 6, a step of exposing the resist film, and developing the resist film to form a resist pattern A resist pattern forming method including the step of: