JP2016212350A - Photosensitive composition for forming insulating film and method for forming insulating film pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive composition capable of improving lithographic characteristics while maintaining high electrical characteristics in the formation of an insulating film, and to provide a method for forming an insulating film pattern using the same.SOLUTION: The photosensitive composition for forming an insulating film contains a silsesquioxane resin (A), an acid generator component (B) which generates an acid upon exposure, and a crosslinking agent component (C). The silsesquioxane resin (A) has a constituent unit (a1) containing a phenolic hydroxyl group and a constituent unit (a2) containing an alkyl group. The acid generator component (B) contains an acid generator (B1) comprising an onium salt which has only one aromatic ring or does not have an aromatic ring in its cationic moiety.SELECTED DRAWING: None

Description

  The present invention relates to a photosensitive composition for forming an insulating film and a method for forming an insulating film pattern.

  In electronic components such as an integrated circuit element, a liquid crystal display element, and a solid-state imaging element, an interlayer insulating film is provided to insulate between wirings arranged in layers. The interlayer insulating film is formed as a fine pattern. For this reason, the photosensitive resin composition is generally used for formation of an interlayer insulation film (for example, refer patent documents 1-3).

For example, in an integrated circuit element, when forming an LSI (Large Scale Integration) multilayer wiring, film formation and processing are repeated, and metal wiring that conducts electricity and an interlayer insulating film that electrically insulates are alternately arranged. It will be done.
The photosensitive resin composition for forming this interlayer insulating film requires high insulation (electrical characteristics) after the interlayer insulating film is formed and good lithography characteristics for realizing fine processing. It is done.

In recent years, with the progress of miniaturization of integrated circuits, the distance between wirings has decreased, and the capacitance between adjacent wirings has increased. The capacitance between the wirings is generated because a partial capacitor is formed by the interlayer insulating film being sandwiched between the wirings.
As a result, the electric capacity between the wires increases, and a phenomenon (signal delay phenomenon) occurs in which the speed of a signal transmitted through the wires is reduced. When the influence of the signal delay phenomenon increases, there is a problem that the processing speed of the integrated circuit element cannot be increased as desired, or the power consumption of the integrated circuit element increases.

Since the electric capacity between the wirings is proportional to the dielectric constant of the interlayer insulating film, the electric capacity between the wirings can be reduced by reducing the dielectric constant of the interlayer insulating film.
On the other hand, Patent Document 4 discloses a silsesquioxane resin having a specific structure, an acid generator component that generates an acid upon exposure, and a crosslinking agent for the purpose of reducing the dielectric constant of the interlayer insulating film. A photosensitive composition containing the above has been proposed.

JP-A-8-262709 JP 2000-162769 A JP 2003-330180 A JP 2011-257635 A

Along with the progress of miniaturization of integrated circuits, the material for forming an insulating film is required to further improve lithography characteristics in order to realize finer processing. However, in conventional photosensitive compositions such as the photosensitive composition described in Patent Document 4, it has been difficult to form an insulating film pattern having a good shape (vertical shape).
The present invention has been made in view of the above circumstances, and a photosensitive composition capable of improving lithography characteristics while maintaining high electrical characteristics in forming an insulating film, and a method for forming an insulating film using the same Is an issue.

  As a result of studies, the inventor has determined that the dielectric constant of the insulating film can be reduced by combining an silium siloxane resin having a specific structure with an onium salt that is highly transparent to exposure light in the application of forming the insulating film. The present inventors have found that the lithography properties such as the pattern shape can be improved while keeping it low, and the present invention has been completed.

  That is, the first aspect of the present invention is a photosensitive composition for forming an insulating film comprising a silsesquioxane resin (A), an acid generator component (B) that generates an acid upon exposure, and a crosslinking agent component (C). The silsesquioxane resin (A) has a structural unit (a1) containing a phenolic hydroxyl group and a structural unit (a2) containing an alkyl group, and the acid generator component (B). Is a photosensitive composition for forming an insulating film comprising an acid generator (B1) made of an onium salt with or without only one aromatic ring in the cation portion.

  The second aspect of the present invention is a film forming process for forming a film on a support using the photosensitive composition for forming an insulating film of the first aspect, an exposure process for selectively exposing the film, It is the formation method of the insulating film pattern which has the image development process which develops the film | membrane after the said exposure, and forms a pre pattern, and the hardening process which hardens | cures the said pre pattern and obtains an insulating film pattern.

According to the photosensitive composition for forming an insulating film of the present invention, it is possible to improve lithography characteristics while maintaining high electrical characteristics in forming an insulating film.
Moreover, according to the insulating film pattern forming method of the present invention, it is possible to form an insulating film pattern with good lithography characteristics while maintaining high electrical characteristics.

<Photosensitive composition for insulating film formation>
The photosensitive composition for forming an insulating film of the present invention (hereinafter also simply referred to as “photosensitive composition”) is obtained by exposure to a silsesquioxane resin (A) (hereinafter also referred to as “component (A)”). An acid generator component (B) that generates an acid (hereinafter also referred to as “component (B)”) and a crosslinking agent component (C) (hereinafter also referred to as “component (C)”) are contained.
The component (A) is a resin that is soluble in an alkaline developer.
In such a photosensitive composition, when an acid is generated from the component (B) upon exposure, the acid acts to cause crosslinking between the component (A) and the component (C), resulting in dissolution in an alkali developer. Sex is reduced. Therefore, in the formation of the insulating film, when the film obtained by coating the photosensitive composition on the support is selectively exposed, the exposed portion turns into poorly soluble in an alkali developer, while the unexposed portion Since it remains soluble in an alkali developer, the unexposed portion is dissolved and removed by development with an alkali developer. Therefore, by selectively exposing through a desired mask pattern, an insulating film having a desired shape can be formed with high accuracy.
In the present invention, “exposure” is a concept including general irradiation of active energy rays such as ultraviolet rays, radiation, and electron beams.

  Such a photosensitive composition is suitable as a material for forming an interlayer insulating film provided to insulate between wirings arranged in layers in electronic components such as liquid crystal display elements, integrated circuit elements, and solid-state imaging elements. It is. Among these, it is particularly suitable as a material for forming an interlayer insulating film in an integrated circuit element.

≪Silsesquioxane resin (A) ≫
The component (A) in the present invention is a silsesquioxane resin having a structural unit (a1) containing a phenolic hydroxyl group and a structural unit (a2) containing an alkyl group, the main chain comprising a Si—O bond. .

・ Structural unit (a1)
The structural unit (a1) in the present invention is a structural unit containing a phenolic hydroxyl group.
Examples of the structural unit (a1) include those in which the main chain portion is an Si—O bond and the side chain portion bonded to the Si atom is a “group containing a phenolic hydroxyl group”.
In the structural unit (a1), the phenolic hydroxyl group forms a crosslinked structure with the component (C) by receiving the action of an acid generated from the component (B) by exposure. Thereby, (A) component becomes high molecular weight. In addition, since the structural unit (a1) contains the phenolic hydroxyl group, the component (A) is soluble in an alkali developer and imparts alkali developability to the photosensitive composition.

  Specific examples of the “group containing a phenolic hydroxyl group” will be shown below. In the chemical formula, * indicates a bond.

As the preferred structural unit (a1), structural units represented by general formula (a1-1) shown below can be mentioned.
In general formula (a1-1), “—O _1/2 —” indicates that this oxygen atom is shared with other structural units.

［式中、Ｒａ^１は、炭素数１〜５のアルキレン基又は単結合である。ｎａ１は、１〜３の整数である。］

[Wherein, Ra ¹ represents an alkylene group having 1 to 5 carbon atoms or a single bond. na1 is an integer of 1 to 3. ]

In the formula (a1-1), Ra ¹ is preferably an alkylene group having 1 to 5 carbon atoms.
The alkylene group in Ra ¹ may be linear, branched or cyclic, and is preferably linear or branched. The number of carbon atoms of the alkylene group for Ra ¹ is 1-5, preferably 1 to 3 carbon atoms. Examples of the alkylene group in Ra ¹ include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, and an isopropylene group. Among these, a methylene group, an ethylene group, a propylene group, and an isopropylene group are preferable. Group and ethylene group are more preferable, and a methylene group is more preferable.

In the formula (a1-1), na1 is an integer of 1 to 3, preferably 1 or 2, and more preferably 1.
The bonding position of the hydroxyl group to the benzene ring may be any of o-position, m-position and p-position. For example, the p-position is preferred industrially.

As the structural unit (a1) contained in the component (A), 1 type of structural unit may be used, or 2 or more types may be used.
The proportion of the structural unit (a1) in the component (A) is preferably 40 to 90 mol%, more preferably 50 to 75 mol%, more preferably 60 to 70, based on the total of all structural units constituting the component (A). More preferred is mol%. The lower the proportion of the structural unit (a1), the higher the electrical characteristics. Further, by setting the proportion of the structural unit (a1) to be equal to or lower than the upper limit value, the dielectric constant of the formed insulating film can be easily suppressed to a lower level. On the other hand, a pre-pattern can be easily formed by setting it as the lower limit value or more.

・ Structural unit (a2)
The structural unit (a2) in the present invention is a structural unit containing an alkyl group.
Examples of the structural unit (a2) include one in which the main chain portion is a Si—O bond and the side chain portion bonded to the Si atom is an alkyl group.
When the component (A) has the structural unit (a2), the dielectric constant of the insulating film formed using the photosensitive composition can be lowered.

As the preferred structural unit (a2), structural units represented by general formula (a2-1) shown below can be mentioned.
In general formula (a2-1), “—O _1/2 —” indicates that this oxygen atom is shared with other structural units.

［式中、Ｒａ^２は、炭素数１〜１０のアルキル基である。］

Wherein, Ra ² is an alkyl group having 1 to 10 carbon atoms. ]

In the formula (a2-1), the alkyl group in Ra ² may be linear, branched or cyclic, and is preferably linear or branched. Carbon number of the alkyl group in Ra ² is 1 to 10, preferably 1 to 5 carbon atoms, and more preferably 1 to 3 carbon atoms. Examples of the alkyl group in Ra ² include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group, isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, 2- An ethylhexyl group etc. are mentioned. Among these, methyl group, ethyl group, propyl group, butyl group, pentyl group, isopropyl group, isobutyl group, sec-butyl group and tert-butyl group are preferable, and methyl group, ethyl group, propyl group and isopropyl group are more preferable. Further, a methyl group and an ethyl group are more preferable, and a methyl group is particularly preferable.

As the structural unit (a2) contained in the component (A), 1 type of structural unit may be used, or 2 or more types may be used.
The proportion of the structural unit (a2) in the component (A) is preferably 10 to 60 mol%, more preferably 25 to 50 mol%, more preferably 30 to 40, based on the total of all structural units constituting the component (A). More preferred is mol%.
By setting the proportion of the structural unit (a2) to be equal to or higher than the lower limit value, the dielectric constant of the formed insulating film can be easily suppressed. On the other hand, by setting it to the upper limit value or less, it becomes easy to balance with the structural unit (a1).

-Other structural unit (A) In addition to a structural unit (a1) and a structural unit (a2), a component (A) may have another structural unit further.
Such other structural units are not particularly limited, and many conventionally known units can be used as those used for resist resins for KrF excimer laser, ArF excimer laser and the like.
Examples of other structural units include structural units represented by the following chemical formula (a3-1-1). The structural unit represented by this chemical formula (a3-1-1) is useful for enhancing the lithography properties. By introducing the structural unit represented by the chemical formula (a3-1-1), the dissolution rate can be easily controlled.

(A) The other structural unit which a component has may be 1 type, and 2 or more types may be sufficient as it.
In the case where the component (A) has other structural units, the proportion of the other structural units in the component (A) is preferably 30 mol% or less with respect to the total of all the structural units constituting the component (A), and 20 moles. % Or less is more preferable, and 10 mol% or less is particularly preferable.

  In the photosensitive composition of the present invention, the component (A) is a silsesquioxane resin having the structural unit (a1) and the structural unit (a2) described above, and is represented by the general formula (a1-1). A silsesquioxane resin having a structural unit represented by formula (a2-1) and a structural unit represented by formula (a2-1) is preferred. The silsesquioxane resin which consists of the structural unit represented by these is more preferable.

  The total content of the structural unit (a1) and the structural unit (a2) contained in the component (A) is preferably 50 mol% or more, and 70 mol% with respect to the total of all structural units constituting the component (A). The above is more preferable, 80 mol% or more is further preferable, 90 mol% or more is particularly preferable, and may be 100 mol% (that is, both of the structural unit (a1) and the structural unit (a2)). Polymer) is most preferred.

In the component (A), the content ratio (molar ratio) between the structural unit (a1) and the structural unit (a2) is preferably structural unit (a1) / structural unit (a2) = 40/60 to 90/10, / 50 to 75/25 is more preferable, and 60/40 to 70/30 is particularly preferable.
By setting the structural unit (a1) / the structural unit (a2) to be equal to or higher than the lower limit value, the lithography characteristics of the formed insulating film can be further improved. By setting the structural unit (a1) / structural unit (a2) to the upper limit value or less, the dielectric constant of the insulating film to be formed can be further suppressed.

The mass average molecular weight (Mw) of the component (A) (polystyrene conversion standard by gel permeation chromatography (GPC)) is not particularly limited, preferably 1000 to 20000, more preferably 1000 to 10000, and 1000 to 5000 is more preferable.
When the Mw of the component (A) is equal to or lower than the upper limit value, the dielectric constant of the formed insulating film can be further suppressed. On the other hand, by being more than the lower limit, the patterning property of the insulating film becomes better, and the lithography characteristics of the formed insulating film are further improved.

(A) component which the photosensitive composition of this invention contains may be 1 type, and 2 or more types may be sufficient as it.
In the photosensitive composition of the present invention, the content of the component (A) may be adjusted according to the film thickness to be formed.

≪Acid generator component (B) ≫
The component (B) in the present invention is an acid generator component that generates an acid upon exposure.
In addition, the component (B) includes an acid generator (B1) (hereinafter also referred to as “component (B1)”) made of an onium salt having or not having only one aromatic ring in the cation portion.
In the photosensitive composition of the present invention, the component (B) may contain an acid generator (B2) other than the component (B1) (hereinafter also referred to as “component (B2)”) in addition to the component (B1). Good.

-(B1) component (B1) component is an onium salt which has only one aromatic ring in a cation part, or does not have. Such a component (B1) is an onium salt that is highly transparent to exposure light. By using the component (B1), exposure light can easily reach the vicinity of the interface between the insulating film pattern and the silicon substrate, and the lithography characteristics of the formed insulating film pattern can be improved.

  The aromatic ring here is not particularly limited as long as it is a cyclic conjugated system having 4n + 2 (where n is 0 and a natural number) π electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene and phenanthrene; aromatic heterocycles in which a part of carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms, and the like. Can be mentioned. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.

As the component (B1), a photodegradable base used for a quencher of a resist composition or an organic cation known as a cation moiety such as an onium-based acid generator of the resist composition can be used. For example, sulfonium Salt or iodonium salt.
As a preferable (B1) component, the compound represented by the following general formula (b1) or the compound represented by the following general formula (b2) is mentioned.

［式中、Ｒｂ^１〜Ｒｂ^５は、それぞれ独立に、置換基を有していてもよいアリール基、アルキル基又はアルケニル基を表し、Ｒｂ^１〜Ｒｂ^３は、相互に結合して式中のイオウ原子と共に環を形成してもよい。但し、Ｒｂ^１〜Ｒｂ^３は、これらの全体で芳香環を１個のみ有するか、又は芳香環を有さない。Ｒｂ^４〜Ｒｂ^５は、これらの全体で芳香環を１個のみ有するか、又は芳香環を有さない。Ａ⁻は、対アニオンを表す。］

[Wherein, Rb ^{1 to} Rb ⁵ each independently represents an aryl group, an alkyl group or an alkenyl group which may have a substituent, and Rb ^{1 to} Rb ³ are bonded to each other to form You may form a ring with a sulfur atom. However, Rb ^{1 to} Rb ³ have only one aromatic ring as a whole or no aromatic ring. Rb ^{4 to} Rb ⁵ have only one aromatic ring as a whole or no aromatic ring. A ⁻ represents a counter anion. ]

.. About the cation part of the compound represented by the general formula (b1) In the formula (b1), Rb ^{1 to} Rb ³ each independently have an aryl group which may have a substituent and a substituent. Represents an alkyl group which may be substituted, or an alkenyl group which may have a substituent.

The aryl group in Rb ¹ ~Rb ^3, include an unsubstituted aryl group having 6 to 20 carbon atoms, a phenyl group, a naphthyl group.
As the alkyl group in Rb ^{1 to} Rb ³ , a chain or cyclic alkyl group having 1 to 30 carbon atoms is preferable.
The alkenyl group in Rb ^{1 to} Rb ³ preferably has 2 to 10 carbon atoms.
Examples of the substituent that Rb ^{1 to} Rb ³ may have include, for example, an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, the following general formula (ca-r-1) to And groups represented by (ca-r-7).

［式中、Ｒ’^２０１は、それぞれ独立に、水素原子、置換基を有していてもよい環式基、置換基を有していてもよい鎖状のアルキル基、又は置換基を有していてもよい鎖状のアルケニル基である。］

[Wherein, each R ′ ²⁰¹ independently has a hydrogen atom, a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a substituent. A chain alkenyl group which may be present. ]

Cyclic group which may have a substituent:
The cyclic group is preferably a cyclic aliphatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.
Examples of the cyclic aliphatic hydrocarbon group include an aliphatic hydrocarbon group containing a ring in the structure.
As the aliphatic hydrocarbon group containing a ring in this structure, an alicyclic hydrocarbon group (a group obtained by removing one hydrogen atom from an aliphatic hydrocarbon ring), an alicyclic hydrocarbon group is linear or branched Examples thereof include a group bonded to the end of a chain aliphatic hydrocarbon group and a group in which an alicyclic hydrocarbon group is interposed in the middle of a linear or branched aliphatic hydrocarbon group.
The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic alicyclic hydrocarbon group, a group in which one or more hydrogen atoms have been removed from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among these, the polycycloalkane includes polycycloalkanes having a polycyclic skeleton of a bridged ring system such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane; condensed ring systems such as a cyclic group having a steroid skeleton A polycycloalkane having a polycyclic skeleton is more preferable.

  Among them, the cyclic aliphatic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from a monocycloalkane or polycycloalkane, more preferably a group obtained by removing one hydrogen atom from a polycycloalkane, and adamantyl. Group and norbornyl group are particularly preferable, and adamantyl group is most preferable.

The linear or branched aliphatic hydrocarbon group that may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and 1 to 4 carbon atoms. Is more preferable, and 1-3 are most preferable.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable. Specifically, a methylene group [—CH ₂ —], an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [ — (CH ₂ ) ₃ —], tetramethylene group [— (CH ₂ ) ₄ —], pentamethylene group [— (CH ₂ ) ₅ —] and the like can be mentioned.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ). _{2 -, - C (CH 3} ) (CH 2 CH 3) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as - _{CH (CH 3) CH 2 -} , - CH (CH 3) CH (CH 3) -, - C (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - C (CH 2 CH _{3) 2} -CH ₂ - alkyl groups such _{as; -CH (CH 3) CH 2} CH 2 -, - CH 2 CH (CH 3) CH 2 - alkyl trimethylene groups such as; -CH _(CH 3) _{CH 2 CH 2 CH 2 -,} - CH 2 CH (CH 3) CH 2 CH 2 - And the like alkyl alkylene group such as an alkyl tetramethylene group of. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

  Further, the cyclic hydrocarbon group may contain a hetero atom such as a heterocyclic ring.

Examples of the substituent in the cyclic group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group.
The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.
The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group. Most preferred is an ethoxy group.
Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
As the halogenated alkyl group as a substituent, a part or all of hydrogen atoms such as an alkyl group having 1 to 5 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, and the like And a group substituted with a halogen atom.
The carbonyl group as a substituent is a group that substitutes a methylene group (—CH ₂ —) constituting a cyclic hydrocarbon group.

A chain-like alkyl group which may have a substituent:
Such a chain alkyl group may be linear or branched.
The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decanyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, Examples include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.

A chain-like alkenyl group which may have a substituent:
Such a chain alkenyl group may be linear or branched, preferably has 2 to 10 carbon atoms, more preferably 2 to 5, still more preferably 2 to 4, and particularly preferably 3 preferable. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched alkenyl group include 1-methylvinyl group, 2-methylvinyl group, 1-methylpropenyl group, 2-methylpropenyl group and the like.
Among the above, the chain alkenyl group is preferably a linear alkenyl group, more preferably a vinyl group or propenyl group, and particularly preferably a vinyl group.

  Examples of the substituent in the chain alkyl group or alkenyl group include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, and the above cyclic aliphatic hydrocarbon group. Can be mentioned.

Among the above, Rb ^{1 to} Rb ³ are preferably an aryl group which may have a substituent or an alkyl group which may have a substituent.

Rb ¹ to Rb ³ in the formula (b1) may be bonded to each other to form a ring together with the sulfur atom in the formula.
When Rb ^{1 to} Rb ³ are bonded to each other to form a ring together with the sulfur atom in the formula, a hetero atom such as a sulfur atom, an oxygen atom or a nitrogen atom, a carbonyl group, —SO—, —SO ₂ —, _{-SO 3 -, - COO -,} - CONH- , or -N _(R N) - (wherein _{R N} is an alkyl group of 1 to 5 carbon atoms.) or may be bonded via a functional group such as. As the ring to be formed, one ring containing a sulfur atom in the ring skeleton in the formula is preferably a 3- to 10-membered ring, particularly a 5- to 7-membered ring, including the sulfur atom. preferable. Specific examples of the ring formed include, for example, thiophene ring, thiazole ring, benzothiophene ring, thianthrene ring, benzothiophene ring, dibenzothiophene ring, 9H-thioxanthene ring, thioxanthone ring, thianthrene ring, phenoxathiin ring, tetrahydro A thiophenium ring, a tetrahydrothiopyranium ring, etc. are mentioned.

However, Rb ^{1 to} Rb ³ have only one aromatic ring as a whole or no aromatic ring. That is, in the formula (b1), the group S ⁺ (Rb ¹ ) (Rb ² ) (Rb ³ ) has only one aromatic ring as a whole or no aromatic ring.
For example, when Rb ² and Rb ³ are bonded to each other and do not form a ring with a sulfur atom in the formula, only one of Rb ^{1 to} Rb ³ has an aromatic ring And the other two are organic groups having no aromatic ring, or all of Rb ^{1 to} Rb ³ are organic groups having no aromatic ring.
For example, when Rb ² and Rb ³ are bonded to each other to form one aromatic ring together with a sulfur atom in the formula, Rb ¹ is an organic group having no aromatic ring.
For example, when Rb ² and Rb ³ are bonded to each other to form a ring with a sulfur atom in the formula, and the ring is an aliphatic ring (ring having no aromaticity) , Rb ¹ is an organic group having one aromatic ring or an organic group having no aromatic ring.
For example, when the ring formed by combining Rb ² and Rb ³ together with the sulfur atom in the formula is a ring containing two or more aromatic rings, the compound in this case does not correspond to the component (B1) .

  Specifically, among the cation moieties of the compound represented by the general formula (b1), specifically, cations represented by the following chemical formulas (m1-1-1) to (m1-1-3), respectively. Is mentioned.

Moreover, in the cation part of the compound represented by the formula (b1), a preferred specific example in which any two of Rb ^{1 to} Rb ³ are bonded to each other to form a ring together with the sulfur atom in the formula. Examples include cations represented by the following formulas (m1-2), (m1-3), and (m1-4), respectively.

［式中、ｕは１〜３の整数である。Ｒ^６ａはアルキレン基であり、Ｒ^６ｂは水素原子、置換基を有していてもよいアルキル基、非芳香族の置換基を有していてもよいフェニル基またはナフチル基である。ただし、Ｒ^６ａ−Ｃ（＝Ｏ）−Ｏ−Ｒ^６ｂはこれらの全体で芳香環を１個のみ有するか、または芳香環を有さない。Ｒ^７ａはアルキレン基であり、Ｒ^７ｂは置換基を有していてもよいアルキル基、置換基を有していてもよいフェニル基またはナフチル基である。ただし、Ｒ^７ａ−Ｃ（＝Ｏ）−Ｒ^７ｂはこれらの全体で芳香環を１個のみ有するか、または芳香環を有さない。Ｒ^８は置換基を有していてもよいアルキル基、非芳香族の置換基を有していてもよいフェニル基またはナフチル基である。ただし、Ｒ^８は芳香環を１個のみ有するか、または芳香環を有さない。］

[Wherein u is an integer of 1 to 3. R ^6a is an alkylene group, and R ^6b is a hydrogen atom, an alkyl group which may have a substituent, a phenyl group or a naphthyl group which may have a non-aromatic substituent. However, R < ^6a > -C (= O) -O-R < ^6b > has only one aromatic ring as a whole, or does not have an aromatic ring. R ^7a is an alkylene group, and R ^7b is an alkyl group which may have a substituent, a phenyl group which may have a substituent, or a naphthyl group. However, R < ^7a > -C (= O) -R < ^7b > has only one aromatic ring as a whole, or does not have an aromatic ring. R ⁸ is an alkyl group which may have a substituent, a phenyl group or a naphthyl group which may have a non-aromatic substituent. However, R ⁸ has only one aromatic ring or no aromatic ring. ]

In the formula, u is an integer of 1 to 3, and 1 or 2 is most preferable.
In the formula, the alkylene group in R ^6a and R ^7a is preferably a linear or branched alkylene group. 1-12 are preferable, as for carbon number of this alkylene group, 1-5 are more preferable, 1-3 are more preferable, and 1 or 2 is especially preferable.
In the formula, as the alkyl group which may have a substituent in R ^6b , R ^7b and R ^8, the alkyl group which may have a substituent described in the description of Rb ¹ to Rb ³ described above. The same thing is mentioned.
As the non-aromatic substituent that the phenyl group or naphthyl group in R ^6b , R ^7b , and R ⁸ may have, the above-described substituents (alkyl group, Rb ¹ to Rb ³⁾ may have. Examples thereof include the same as the halogen atom, halogenated alkyl group, carbonyl group, cyano group, amino group, and groups represented by the following general formulas (ca-r-1) to (ca-r-7)).

  Preferable examples of the cation represented by the formula (m1-2), (m1-3) or (m1-4) include those shown below.

In formula (m1-4-2), R ^C is a substituent. As the substituent, the above-described substituents that Rb ¹ to Rb ³ may have (an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, the following general formula (ca-r -1) to the groups represented by (ca-r-7), respectively.

Among them, as the cation part of the compound represented by the general formula (b1), when any two of Rb ^{1 to} Rb ³ are bonded to each other to form a ring together with the sulfur atom in the formula Is preferred.
Among them, the cation represented by the formula (m1-4) is more preferable, and selected from the group consisting of cations represented by the formulas (m1-4-1) to (m1-4-6). 1 or more types are more preferable, and the cation represented by the above formula (m1-4-2) is particularly preferable.

.. About the cation moiety of the compound represented by the general formula (b2) In the formula (b2), Rb ^{4 to} Rb ⁵ each independently have an aryl group which may have a substituent and a substituent. Represents an alkyl group which may be substituted, or an alkenyl group which may have a substituent. Examples of Rb ⁴ to Rb ⁵ are the same as those of Rb ¹ to Rb ³ described above.
However, Rb ^{4 to} Rb ⁵ have only one aromatic ring as a whole or no aromatic ring. That is, only one of Rb ^{4 to} Rb ⁵ is an aromatic ring, or none is an aromatic ring.

-About each anion part of the compound represented by general formula (b1) or general formula (b2) In said formula (b1) or formula (b2), A < ^- > represents a counter anion.
The counter anion of A ⁻ is not particularly limited, and, for example, those conventionally known as the anion part of an onium salt acid generator for resist compositions can be appropriately used.
Examples of A ⁻ include an anion represented by a general formula “R ⁴ ” SO ₃ ⁻ ”.

In the general formula “R ⁴ ″ SO ₃ ⁻ ”, R ⁴ ″ represents a linear, branched or cyclic alkyl group, halogenated alkyl group or alkenyl group which may have a substituent.

The linear or branched alkyl group as R ⁴ ″ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and 1 to 4 carbon atoms. Most preferred.
The cyclic alkyl group as R ⁴ ″ preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
In the case where R ⁴ ″ is an alkyl group, examples of “R ⁴ ″ SO ₃ ⁻ ” include methane sulfonate, n-propane sulfonate, n-butane sulfonate, n-octane sulfonate, 1-adamantane sulfonate, 2-norbornane sulfonate, Examples thereof include alkyl sulfonates such as d-camphor-10-sulfonate.

The halogenated alkyl group as R ⁴ ″ is one in which part or all of the hydrogen atoms in the alkyl group are substituted with halogen atoms, and the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, Among them, a linear or branched alkyl group is more preferable, and it is a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a tert-pentyl group, or an isopentyl group. More preferable examples of the halogen atom substituted with a hydrogen atom include a fluorine atom, a chlorine atom, an iodine atom, a bromine atom, etc. In a halogenated alkyl group, a hydrogen atom of an alkyl group (an alkyl group before halogenation) It is preferable that 50 to 100% of all the hydrogen atoms are substituted with halogen atoms, and all the hydrogen atoms are substituted with halogen atoms. It is more preferable to have.
Here, the halogenated alkyl group is preferably a fluorinated alkyl group. 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.
Further, the fluorination rate of the fluorinated alkyl group is preferably 10 to 100%, more preferably 50 to 100%. Particularly, when all the hydrogen atoms are substituted with fluorine atoms, the strength of the acid is increased. preferable.
Specific examples of such a preferred fluorinated alkyl group include a trifluoromethyl group, a heptafluoro-n-propyl group, and a nonafluoro-n-butyl group.

The alkenyl group as R ⁴ ″ is preferably an alkenyl group having 2 to 10 carbon atoms.

In the above R ⁴ ″, “may have a substituent” means that part or all of the hydrogen atoms in the linear, branched or cyclic alkyl group, halogenated alkyl group or alkenyl group are It means that it may be substituted with a substituent (an atom or group other than a hydrogen atom).
The number of substituents in R ⁴ ″ may be one or two or more.

Examples of the substituent include a halogen atom, a hetero atom, an alkyl group, and a formula: X ³ -Q ′-[where Q ′ is a divalent linking group containing an oxygen atom, and X ³ represents a substituent. It is a C1-C30 hydrocarbon group which you may have. ] Etc. which are represented by these.
Examples of the halogen atom and alkyl group include the same groups as those described as the halogen atom and alkyl group in the halogenated alkyl group in R ⁴ ″.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.

In the group represented by X ³ —Q′—, Q ′ is a divalent linking group containing an oxygen atom.
Q ′ may contain atoms other than oxygen atoms. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, oxygen atoms, sulfur atoms, and nitrogen atoms.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond: —O—), an ester bond (—C (═O) —O—), and an amide bond (—C (═O) —NH. -), A carbonyl group (-C (= O)-), a non-hydrocarbon oxygen atom-containing linking group such as a carbonate bond (-O-C (= O) -O-); the non-hydrocarbon oxygen atom Examples include a combination of a containing linking group and an alkylene group. A sulfonyl group (—SO ₂ —) may be further linked to the combination.
Examples of the combination include —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) —O—R ⁹³ —O—C (═O) —, —SO _2- O—R ⁹⁴ —O—C (═O) —, —R ⁹⁵ —SO ₂ —O—R ⁹⁴ —O—C (═O) — (wherein R ^{91 to} R ⁹⁵ are each independently alkylene. Group.) And the like.
The alkylene group for R ^{91 to} R ⁹⁵ is preferably a linear or branched alkylene group, and the alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. preferable.
Specific examples of the alkylene group include a methylene group [—CH ₂ —]; —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ) ₂ —, —C ( _{CH 3) (CH 2 CH 3} ) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as ethylene group _[-CH 2 CH _2— ]; —CH (CH ₃ ) CH ₂ —, —CH (CH ₃ ) CH (CH ₃ ) —, —C (CH ₃ ) ₂ CH ₂ —, —CH (CH ₂ CH ₃ ) CH ₂ — and the like. Alkylethylene groups; trimethylene groups (n-propylene groups) [—CH ₂ CH ₂ CH ₂ —]; alkyls such as —CH (CH ₃ ) CH ₂ CH ₂ — and —CH ₂ CH (CH ₃ ) CH ₂ — trimethylene; tetramethylene group _[-CH 2 _CH 2 C _{2 CH 2 -]; - CH} (CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 - alkyl tetramethylene group and the like; pentamethylene group _[-CH 2 _CH 2 CH ₂ CH ₂ CH ₂ —] and the like.
Q ′ is preferably a divalent linking group containing an ester bond or an ether bond, and among them, —R ⁹¹ —O—, —R ⁹² —O—C (═O) — or —C (═O) — O—R ⁹³ —O—C (═O) — is preferred.

In the group represented by X ³ -Q′-, examples of the hydrocarbon group for X ³ include aliphatic hydrocarbon groups.

The aliphatic hydrocarbon group for X ³ may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
In X ³ , the aliphatic hydrocarbon group may be a group in which a part of carbon atoms constituting the aliphatic hydrocarbon group may be substituted with a substituent containing a hetero atom, and hydrogen constituting the aliphatic hydrocarbon group A part or all of the atoms may be substituted with a substituent containing a hetero atom.
The “heteroatom” in X ³ is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may be composed of only the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of the carbon atom include —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O. —, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group, an acyl group, etc.), —S—, —S (═O) ₂ —, — S (= O) ₂ —O— and the like can be mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent for substituting part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

Examples of the aliphatic hydrocarbon group include a linear or branched saturated hydrocarbon group, a linear or branched monovalent unsaturated hydrocarbon group, or a cyclic aliphatic hydrocarbon group (aliphatic ring). Formula group) is preferred.
The linear saturated hydrocarbon group (alkyl group) preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
The branched saturated hydrocarbon group (alkyl group) preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, Examples include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.

As an unsaturated hydrocarbon group, it is preferable that carbon number is 2-10, 2-5 are preferable, 2-4 are preferable, and 3 is especially preferable. Examples of the linear monovalent unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched monovalent unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group.
Among the above, the unsaturated hydrocarbon group is particularly preferably a propenyl group.

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms are removed from a monocycloalkane; a group in which one or more hydrogen atoms are removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
When the aliphatic cyclic group does not contain a substituent containing a hetero atom in the ring structure, the aliphatic cyclic group is preferably a polycyclic group, and has one or more hydrogen atoms from the polycycloalkane. Excluded groups are preferred, and most preferred are groups in which one or more hydrogen atoms have been removed from adamantane.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include groups represented by the following formulas (L1) to (L6) and (S1) to (S4), respectively.

［式中、Ｑ”は炭素数１〜５のアルキレン基、−Ｏ−、−Ｓ−、−Ｏ−Ｒ^９４’−または−Ｓ−Ｒ^９５’−であり、Ｒ^９４’およびＲ^９５’はそれぞれ独立に炭素数１〜５のアルキレン基であり、ｍは０または１の整数である。］

[In the formula, Q ″ represents an alkylene group having 1 to 5 carbon atoms, —O—, —S—, —O—R ⁹⁴ ′ — or —S—R ⁹⁵ ′ —, and R ⁹⁴ ′ and R ⁹⁵ ′ are Each independently represents an alkylene group having 1 to 5 carbon atoms, and m is an integer of 0 or 1.]

In the formula, examples of the alkylene group for Q ″, R ⁹⁴ ′ and R ⁹⁵ ′ include the same alkylene groups as those described above for R ^{91 to} R ⁹⁵ .
In these aliphatic cyclic groups, a part of hydrogen atoms bonded to carbon atoms constituting the ring structure may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
As said alkyl group, a C1-C5 alkyl group is preferable, and it is especially preferable that they are a methyl group, an ethyl group, a propyl group, n-butyl group, and a tert- butyl group.
Examples of the alkoxy group and the halogen atom are the same as those exemplified as the substituent for substituting part or all of the hydrogen atoms.

In the present invention, X ³ is preferably a cyclic aliphatic hydrocarbon group (aliphatic cyclic group), more preferably an aliphatic cyclic group which may have a substituent.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. The polycyclic aliphatic cyclic group is a group obtained by removing one or more hydrogen atoms from the polycycloalkane, represented by any one of (L2) to (L6) and (S3) to (S4). And the like are preferred.

Among the above, R ⁴ ″ preferably has a halogenated alkyl group or X ³ -Q′— as a substituent.
In the case of having X ³ -Q′- as a substituent, R ⁴ ″ is X ³ -Q′-Y ^3- [wherein Q ′ and X ³ are the same as defined above, and Y ³ represents a substituent. A C1-C4 alkylene group which may have or a C1-C4 fluorinated alkylene group which may have a substituent.] Is preferable.
In the group represented by X ³ -Q′—Y ³ —, the alkylene group for Y ³ includes the same alkylene groups as those described above for Q ′ having 1 to 4 carbon atoms.
Examples of the fluorinated alkylene group include groups in which part or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms.
As Y ^3, _{specifically, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF (CF 2 CF 3) -, _{-C (CF 3) 2 -,} - CF 2 CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF ₃ ) —, —C (CF ₃ ) ₂ CF ₂ —, —CF (CF ₂ CF ₃ ) CF ₂ —, —CF (CF ₂ CF ₂ CF ₃ ) —, —C (CF ₃ ) (CF _{2 CF 3) -; - CHF} -, - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -, - CH (CF 3) CH 2 -, - CH (CF 2 _{CF 3) -, - C (} CH 3) (CF 3) -, - CH 2 CH 2 CH 2 CF 2 -, - C H ₂ CH ₂ CF ₂ CF ₂ —, —CH (CF ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CF ₃ ) CH ₂ —, —CH (CF ₃ ) CH (CF ₃ ) —, —C ( _{CF 3) 2 CH 2 -;} - CH 2 -, - CH 2 CH 2 -, - CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 -, - CH (CH 2 CH 3) -, - _{C (CH 3) 2 -,} - CH 2 CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 -, - CH (CH 3) CH _{(CH 3) -, - C} (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - CH (CH 2 CH 2 CH 3) -, - C (CH 3) (CH 2 CH ₃ ) — and the like.

Y ³ is preferably a fluorinated alkylene group, and particularly preferably a fluorinated alkylene group in which the carbon atom bonded to the adjacent sulfur atom is fluorinated. Examples of such fluorinated alkylene _{group, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF 2 CF 2 CF 2 CF 2 _{-, - CF (CF 3)} CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF 3) -, - C (CF 3) 2 CF 2 -, _{-CF (CF 2 CF 3) CF} 2 -; - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -; - CH 2 CH 2 CH 2 CF 2 -, - CH ₂ CH ₂ CF ₂ CF ₂ —, —CH ₂ CF ₂ CF ₂ CF ₂ — and the like can be mentioned.
Of _{these, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, or _CH 2 _CF 2 CF ₂ - is _{preferable, -CF 2 -, - CF 2} CF 2 - or -CF ₂ CF ₂ CF ₂ - is more preferable, -CF ₂ - is particularly preferred.

The alkylene group or fluorinated alkylene group may have a substituent. An alkylene group or a fluorinated alkylene group has a “substituent” means that part or all of the hydrogen atom or fluorine atom in the alkylene group or fluorinated alkylene group is substituted with an atom or group other than a hydrogen atom and a fluorine atom. Means that
Examples of the substituent that the alkylene group or fluorinated alkylene group may have include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxyl group.

R ⁴ "is ^{X 3 -Q'-Y} 3 - is a group represented ^by, R 4" SO ₃ ^- Examples of, for example represented by any one of the following formulas (b1) ~ (b7) Anions.

［式中、ｑ１〜ｑ２はそれぞれ独立に１〜５の整数であり、ｑ３は１〜１２の整数であり、ｔ３は１〜３の整数であり、ｒ１〜ｒ２はそれぞれ独立に０〜３の整数であり、ｉは１〜２０の整数であり、Ｒ^７は置換基であり、ｎ１〜ｎ３及びｎ６はそれぞれ独立に０または１であり、ｖ０〜ｖ３及びｖ６はそれぞれ独立に０〜３の整数であり、ｗ１〜ｗ３及びｗ６はそれぞれ独立に０〜３の整数であり、Ｑ”は前記と同じである。］

[Wherein, q1 to q2 are each independently an integer of 1 to 5, q3 is an integer of 1 to 12, t3 is an integer of 1 to 3, and r1 to r2 are each independently 0 to 3] I is an integer of 1 to 20, R ⁷ is a substituent, n1 to n3 and n6 are each independently 0 or 1, and v0 to v3 and v6 are each independently 0 to 3. It is an integer, w1-w3 and w6 are each independently an integer of 0-3, and Q ″ is the same as above.]

As the substituent for R ^7, the same as those described as the substituent which may substitute a part of the hydrogen atoms bonded to the carbon atoms constituting the ring structure of the aliphatic cyclic group in the description of X ³ above. Can be mentioned.
Reference numeral of R ⁷ when (r1 and r2, w1 to w3 and w6) is an integer of 2 or more, a plurality of the ^{R 7} groups may be the same, respectively, may be different.

Examples of A ^{− in} the formula (b1) or the formula (b2) include an anion represented by the following general formula (b-3) and an anion represented by the following general formula (b-4). It is done.

［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

In the formula (b-3), 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 preferably has 2 to 6 carbon atoms. More preferably 3 to 5 carbon atoms, most preferably 3 carbon atoms.
In formula (b-4), Y ″ and Z ″ each independently represent a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the carbon number of the alkyl group Is preferably 1 to 10, more preferably 1 to 7 carbon atoms, and most preferably 1 to 3 carbon atoms.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is small for reasons such as good solubility in the component (S) described below within the above carbon number range. The more preferable.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, the strength of the acid increases as the number of hydrogen atoms substituted with fluorine atoms increases, and high-energy light or electron beam of 200 nm or less This is preferable because the transparency to the surface is improved.
The fluorination rate of the alkylene group or alkyl group is preferably 70 to 100%, more preferably 90 to 100%, and most preferably a perfluoroalkylene group or a perfluoroalkylene group in which all hydrogen atoms are substituted with fluorine atoms. A fluoroalkyl group;

Each anion moiety of the Among the general formula (b1) or the compound represented by formula (b2) (A ^-) as the above general formula ^"R 4 ^- halogenation" SO ₃ ^{"R 4} in" An anion which is an alkyl group is preferred, and among them, a fluorinated alkyl sulfonate ion is more preferred.

The component (B1) contained in the photosensitive composition of the present invention may be one type or two or more types.
As the component (B1), a compound represented by the general formula (b1) is preferable, the cation part is a cation represented by the formula (m1-4), and the anion part is a fluorinated alkyl sulfonate ion. An acid generator composed of a compound is more preferable.
In addition, as the component (B1), a combination of two compounds in which the cation portion is a cation represented by the formula (m1-4) and the anion portion is a fluorinated alkyl sulfonate ion having a different carbon number. It is also preferable to use them.

In the photosensitive composition of the present invention, the content of the component (B1) is preferably 0.1 to 30 parts by mass, more preferably 0.2 to 20 parts by mass with respect to 100 parts by mass of the component (A). More preferably, it is 5-15 mass parts.
When the content of the component (B1) is equal to or higher than the lower limit, the resolution is improved in the formation of the insulating film, and the lithography characteristics are further improved. On the other hand, by being below the upper limit value, when each component of the photosensitive composition is dissolved in an organic solvent, a uniform solution is easily obtained, and the storage stability is further improved.

-(B2) component (B2) component is an acid generator which generate | occur | produces an acid by exposure except the above-mentioned (B1) component.
The component (B2) is not particularly limited as long as it is other than the component (B1), and those that have been proposed as acid generators for chemically amplified resist compositions can be used.
Examples of the component (B2) include oxime sulfonate acid generators; diazomethane acid generators such as bisalkyl or bisarylsulfonyldiazomethanes and poly (bissulfonyl) diazomethanes; nitrobenzyl sulfonate acid generators, iminos Examples thereof include sulfonate acid generators and disulfone acid generators.

  Examples of the oxime sulfonate acid generator include α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (propylsulfonyloxyimino) -p-methylphenylacetonitrile, α- ( And methylsulfonyloxyimino) -p-bromophenylacetonitrile, bis-o- (n-butylsulfonyl) -α-dimethylglyoxime, and the like.

Among diazomethane acid generators, bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, bis (cyclohexyl). Sulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane, 1,4-bis (phenylsulfonyldiazomethylsulfonyl) butane, 1,6-bis (phenylsulfonyldiazomethyl). Sulfonyl) hexane, 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane, 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane, 1,3-bis (cyclohexylsulfonyldiazomethylsulfonyl) propane, 1,6- Examples thereof include bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (cyclohexylsulfonyldiazomethylsulfonyl) decane and the like.
(B2) A component may be used individually by 1 type and may use 2 or more types together.
When the photosensitive composition of this invention contains (B2) component, 30 mass parts or less are preferable with respect to 100 mass parts of (A) component, and, as for content of (B2) component, 0.5-15 mass parts Is more preferable.

≪Crosslinking agent component (C) ≫
(C) component in this invention is a crosslinking agent component.
The component (C) is subjected to the action of an acid generated from the component (B) by exposure to form a crosslinked structure with the phenolic hydroxyl group contained in the structural unit (a1) in the component (A).
As such component (C), a crosslinking agent blended in a known chemically amplified negative resist composition can be used.

As the component (C), for example, an amino group-containing compound (melamine, acetoguanamine, benzoguanamine, urea, ethyleneurea, glycoluril, etc.) is reacted with formaldehyde or formaldehyde and a lower alcohol, and a hydrogen atom of the amino group is reacted. Examples include compounds substituted with a hydroxymethyl group or a lower alkoxymethyl group.
Specific examples of such component (C) include hexamethoxymethylmelamine, bismethoxymethylurea, bismethoxymethylbismethoxyethyleneurea, tetrakismethoxymethylglycoluril, tetrakisbutoxymethylglycoluril and the like. Among these, a compound in which urea is reacted with formaldehyde, or formaldehyde and a lower alcohol, and a hydrogen atom of the amino group is substituted with a hydroxymethyl group or a lower alkoxymethyl group, among them, for example, bismethoxymethylurea is This is particularly preferable in that a good insulating film pattern is easily formed without being greatly influenced by the amount of the compound.

(C) component which the photosensitive composition of this invention contains may be 1 type, and 2 or more types may be sufficient as it.
In the photosensitive composition of the present invention, the content of the component (C) is preferably 3 to 30 parts by mass, more preferably 5 to 20 parts by mass, and 5 to 15 parts by mass with respect to 100 parts by mass of the component (A). Is more preferable. When the content of the component (C) is equal to or higher than the lower limit value, the crosslinking reaction proceeds sufficiently, and a good insulating film pattern is easily obtained. On the other hand, the storage stability of a photosensitive composition improves more by being below an upper limit.

≪Optional ingredient≫
The photosensitive composition of the present invention contains components (arbitrary components) other than the above-mentioned (A) component, (B) component and (C) component as necessary, as long as the effects of the present invention are not impaired. Also good.
In the photosensitive composition of the present invention, in addition to the component (A), the component (B) and the component (C), a nitrogen-containing organic compound (D) (hereinafter also referred to as “component (D)”). It is preferable to contain. The component (D) acts as a quencher (acid diffusion controller) that traps acid generated by exposure in the photosensitive composition. By adding the component (D) to the photosensitive composition, the lithography characteristics of the insulating film pattern to be formed are further improved, and the temporal stability of the photosensitive composition is improved.

As the component (D), what has been proposed as an acid diffusion control agent for a chemically amplified resist composition can be used, and amines, particularly secondary aliphatic amines or tertiary aliphatic amines, among others, can be used. Are preferably used.
Specific examples of the component (D) include trimethylamine, diethylamine, triethylamine, di-n-propylamine, tri-n-propylamine, tripentylamine, tri-n-heptylamine, tri-n-octylamine, di- alkylamines such as n-heptylamine, di-n-octylamine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, tri-n-octanolamine And alkyl alcohols.
(D) component which the photosensitive composition of this invention contains may be 1 type, and 2 or more types may be sufficient as it.
When the photosensitive composition of this invention contains (D) component, 0.01-10 mass parts is preferable with respect to 100 mass parts of (A) component, and, as for content of (D) component, 0.01- 5 parts by mass is more preferable. When content of (D) component is more than a lower limit, the lithography characteristic of the insulating film pattern formed is improved more. On the other hand, by being below the upper limit value, it is easy to suppress a decrease in sensitivity of the photosensitive composition due to the addition of the component (D).

  If desired, the photosensitive composition of the present invention further contains a miscible additive, for example, an additional resin for improving the properties of the formed insulating film, a surfactant for improving the coating property, Plasticizers, stabilizers, colorants, antihalation agents and the like may be added as appropriate. As these additives, known ones can be used without particular limitation.

The photosensitive composition of the present invention is produced by dissolving the above-mentioned component (A), component (B), component (C), and optional components in an organic solvent component (hereinafter also referred to as “(S) component”). be able to.
As the component (S), any component can be used as long as it can dissolve each component to be blended to form a uniform solution, and any conventionally known solvent as a chemically amplified resist composition can be used. It can be appropriately selected and used. Moreover, improvement of applicability and viscosity adjustment can be achieved by blending the component (S).

  The component (S) is not particularly limited, for example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone; ethylene glycol Polyhydric alcohols such as diethylene glycol, propylene glycol, dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, the polyhydric alcohols or Monoalkyl ethers such as monomethyl ether, monoethyl ether, monopropyl ether and monobutyl ether of the compound having an ester bond, or Derivatives of polyhydric alcohols such as compounds having an ether bond such as nophenyl ether [in these, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred]; cyclic compounds such as dioxane Ethers and esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; methyl carbonate, ethyl carbonate, Propyl carbonate, butyl carbonate; anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene And aromatic organic solvents such as benzene, isopropylbenzene, benzene, toluene, xylene, cymene and mesitylene, and dimethyl sulfoxide (DMSO).

(S) component which the photosensitive composition of this invention contains may be 1 type, and 2 or more types may be sufficient as it.
Among the above, PGMEA, PGME, γ-butyrolactone, EL, and cyclohexanone are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is also preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range.
More specifically, when EL or cyclohexanone is blended as the polar solvent, the mass ratio of PGMEA: EL or cyclohexanone is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. . Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3. Furthermore, a mixed solvent of PGMEA, PGME, and cyclohexanone is also preferable.
In addition, as the component (S), 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 component (S) used is not particularly limited, and is appropriately set according to the coating film thickness at a concentration at which the photosensitive composition can be applied to a substrate or the like. For example, the component (S) is used so that the solid content concentration of the photosensitive composition is preferably in the range of 2 to 30% by mass, more preferably 5 to 20% by mass.

  The photosensitive composition of the present invention can be prepared by a conventional method. For example, the photosensitive composition is prepared by mixing the above-described components (A), (B), (C), and optional components with a stirrer and, if necessary, filtering with a filter such as a membrane filter. The

As explained above, the photosensitive composition for forming an insulating film of the present invention has both a silsesquioxane resin (A), an acid generator component (B), and a crosslinking agent component (C).
In such a photosensitive composition, (A) component having the structural unit (a1) and structural unit (a2), and (B) component having only one aromatic ring in the cation moiety or no onium Since the combination of the salt (component (B1)) and the insulating film formed has a low dielectric constant, high electrical characteristics are maintained. In addition, in such a photosensitive composition, for example, an insulating film pattern having a highly perpendicular shape can be formed, and lithography properties can be improved.

<Method for forming insulating film pattern>
The method for forming an insulating film pattern of the present invention includes a film forming step of forming a film on a support using the photosensitive composition for forming an insulating film of the present invention, an exposure step of selectively exposing the film, It has the image development process which develops the film | membrane after the said exposure, and forms a pre pattern, and the hardening process which hardens | cures the said pre pattern. The insulating film can be formed as follows, for example.

[Film formation process]
In the film forming step, a film is formed on the support using the photosensitive composition for forming an insulating film of the present invention.
First, the photosensitive composition for forming an insulating film of the present invention is applied onto a support with a spinner or the like, and a baking (post-apply bake (PAB)) treatment is performed at a temperature of 80 to 150 ° C., for example. It is applied for ˜120 seconds, preferably 60 to 90 seconds, to form a film of the photosensitive composition.
At this time, the thickness of the film of the photosensitive composition formed is preferably 500 nm to 5 μm, more preferably 700 nm to 2 μm, and particularly preferably 1 μm to 2 μm. The thicker the photosensitive composition film, the more remarkable the effect of the present invention. For example, even when the thickness of the film is 700 nm or more, it is possible to form an insulating film pattern having a highly perpendicular shape while maintaining high electrical characteristics.

  The support is not particularly limited, and a conventionally known one can be used. Examples thereof include a substrate for electronic parts and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, and a glass substrate provided with a black matrix, a color filter, a polarizing plate, and the like as necessary can be used.

[Exposure process]
Next, the film of the photosensitive composition is selectively exposed through a mask (mask pattern) on which a predetermined pattern is formed. By this exposure, an acid is generated from the component (B) contained in the film. This acid acts to cause cross-linking between the component (A) and the component (C), and the exposed portion of the film turns to be hardly soluble in an alkali developer.
The exposure here is performed by irradiating active energy rays such as ultraviolet rays, excimer laser light (KrF excimer laser, ArF excimer laser, etc.), radiation, electron beam, or the like. Examples of the active energy ray light source include a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a chemical lamp, and an excimer laser generator. The energy dose to be irradiated varies depending on the composition of the photosensitive composition, but is, for example, about 1 to 2000 mJ / cm ² .

  After the film of the photosensitive composition is exposed, a baking (post-exposure baking (PEB)) treatment is performed, for example, at a temperature of 80 to 150 ° C. for 40 to 120 seconds, preferably 60 to 90 seconds.

[Development process]
Next, the exposed film is developed. By development, an unexposed portion of the film is dissolved and removed, and a pre-pattern is formed.
The development here is performed using, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH).
Development can be carried out by a known development method. For example, a method in which a support is immersed in a developer for a certain period of time (dip method), a developer is raised on the surface of the support by surface tension, and is allowed to stand for a certain period of time. Method (Paddle method), Method of spraying developer on the surface of support (spray method), Continuous application of developer while scanning developer coating nozzle at constant speed on support rotating at constant speed And a method (dynamic dispensing method).

After the development, a rinsing process is preferably performed. The rinse treatment is preferably a water rinse using pure water as a rinse solution.
A well-known additive can be mix | blended with a rinse liquid as needed. Examples of the additive include a surfactant. The surfactant is not particularly limited. For example, ionic or nonionic fluorine-based and / or silicon-based surfactants can be used.
The rinse treatment (washing treatment) using the rinse liquid can be performed by a known rinse method.

[Curing process]
Next, an insulating film pattern is obtained by heat-treating and curing the pre-pattern after development or rinse treatment.
The heating temperature at that time is determined in consideration of the composition of the photosensitive composition, and is preferably 150 to 600 ° C., for example. You may perform heat processing, changing heating temperature in the said range (150-600 degreeC).

  In the method for forming an insulating film of the present invention described above, since the photosensitive composition of the present invention is used, an insulating film pattern with good lithography characteristics can be formed while maintaining high electrical characteristics.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.

<Preparation of photosensitive composition>
(Examples 1-6, Comparative Examples 1-3)
By dissolving the mixture obtained by mixing each component shown in Table 1 in a mixed solvent of propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 30/70 (mass ratio) so as to have a solid content concentration of 20% by mass, The photosensitive composition of each example was prepared, respectively.
The compounding amount of the acid generator component was set so that the amount of the acid generator component contained in each photosensitive composition of Examples 2, 4 to 6 and Comparative Examples 1 to 3 was equimolar.
The compounding amount of the nitrogen-containing organic compound was set in consideration of the exposure amount in the later-described exposure step.

In Table 1, each abbreviation has the following meaning. The numerical value in [] is a compounding amount (part by mass).
(A) -1: Silsesquioxane resin having two structural units represented by the following chemical formula (A) -1. The mass average molecular weight (Mw) was 4770, and the copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) was 1 / m = 60/40.
(A) -2: Silsesquioxane resin having two structural units represented by the following chemical formula (A) -2. The weight average molecular weight (Mw) was 4180, and the copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) was 1 / m = 70/30.
(A) -3: Silsesquioxane resin having two structural units represented by the following chemical formula (A) -3. The mass average molecular weight (Mw) was 7010, and the copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) was 1 / m = 70/30.

The mass average molecular weight (Mw) is a value in terms of standard polystyrene determined by GPC measurement. The copolymer composition ratio is a value determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR).

(B) -1: An acid generator composed of an onium salt represented by the following chemical formula (B) -1.
(B) -2: An acid generator composed of an onium salt represented by the following chemical formula (B) -2.
(B) -3: An acid generator composed of an onium salt represented by the following chemical formula (B) -3.
(B) -4: An acid generator composed of an onium salt represented by the following chemical formula (B) -4.

  (C) -1: a compound represented by the following chemical formula (C) -1, a trade name “Nicalak MX-270”, manufactured by Sanwa Chemical Co., Ltd.

(D) -1: Triisopropanolamine.
Add-1: Surfactant, trade name “POLYFOX PF-656”, manufactured by Omniva.

<Evaluation>
Using the photosensitive composition of each example, an insulating film pattern was formed by the following insulating film forming method.
Then, for the formed insulating film pattern, each evaluation of electrical characteristics and lithography characteristics was performed as follows.

<< Formation of insulating film >>
[Film formation process]
The photosensitive composition of each example was apply | coated uniformly using the spinner on the 8-inch silicon substrate which performed the hexamethyldisilazane (HMDS) process for 36 seconds at 90 degreeC. Thereafter, a baking (post-apply baking (PAB)) treatment at 100 ° C. for 90 seconds was performed and dried to form a photosensitive composition film (film thickness: 1.0 μm).

[Exposure process]
Next, an NSR-S203 type exposure apparatus (manufactured by Nikon Corporation; NA / σ = 0.68 / 0.75) is used for the formed photosensitive composition film, and a line and space mask pattern (binary mask) is used. ) To selectively expose a KrF excimer laser (exposure dose 40 mJ / cm ² ).
Thereafter, post-exposure heating (PEB) treatment was performed at 110 ° C. for 90 seconds.

[Development process]
Next, at 23 ° C., using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) (trade name “NMD-3”, manufactured by Tokyo Ohka Kogyo Co., Ltd.), alkali development is performed for 240 seconds, A pre-pattern was formed.
Then, the rinse process with a pure water was performed.

[Curing process]
Next, under a N ₂ atmosphere, the heat treatment was continued at 180 ° C. for 10 minutes, 280 ° C. for 10 minutes, and 400 ° C. for 30 minutes to cure the prepattern.
As a result, in each example, a line-and-space insulating film pattern having a line width of 400 nm / pitch width of 800 nm was formed.

≪Evaluation of electrical characteristics≫
A part of the insulating film pattern formed above was cut out from the silicon substrate, aluminum was vapor-deposited on the cut out insulating film pattern, and the dielectric constant was measured with a measuring instrument (type: E4980A, manufactured by Agilent).
Then, using the measured dielectric constant as an index, the electrical characteristics of the insulating film pattern were evaluated according to the following evaluation criteria. The results are shown in Table 2.
Evaluation criteria for electrical characteristics ○: Dielectric constant is less than 3.90. X: Dielectric constant is 3.90 or more.

≪Evaluation of lithography characteristics≫
The line-and-space-shaped insulating film pattern formed as described above was observed using a length measurement SEM. A scanning electron microscope (trade name “S-9380”, manufactured by Hitachi High-Technologies Corporation) was used for the length measurement SEM.
Then, the shape of the insulating film pattern is determined by using the angle (taper angle) formed by the inner surface of the line portion of the insulating film pattern at the interface between the insulating film pattern and the silicon substrate and the silicon substrate surface as an index, according to the following evaluation criteria. The lithography characteristics of the insulating film pattern were evaluated. The results are shown in Table 2.
Evaluation Criteria for Lithographic Properties ○: Taper angle is less than 91 °. X: The taper angle is 91 ° or more.

  From the results shown in Table 2, it was confirmed that according to the photosensitive compositions of Examples 1 to 6 to which the present invention was applied, the dielectric constant was kept low and an insulating film pattern with a high perpendicularity could be formed. it can.

Claims (9)

A photosensitive composition for forming an insulating film comprising a silsesquioxane resin (A), an acid generator component (B) that generates acid upon exposure, and a crosslinking agent component (C),
The silsesquioxane resin (A) has a structural unit (a1) containing a phenolic hydroxyl group and a structural unit (a2) containing an alkyl group,
The said acid generator component (B) contains the acid generator (B1) which consists of onium salt which has only one aromatic ring in a cation part, or does not have, The photosensitive composition for insulating film formation characterized by the above-mentioned . 2. The photosensitive composition for forming an insulating film according to claim 1, wherein the structural unit (a1) is a structural unit represented by the following general formula (a1-1).

[Wherein, Ra ¹ represents an alkylene group having 1 to 5 carbon atoms or a single bond. na1 is an integer of 1 to 3. ] The said structural unit (a2) is a photosensitive composition for insulating film formation of Claim 1 or 2 which is a structural unit represented by the following general formula (a2-1).

Wherein, Ra ² is an alkyl group having 1 to 10 carbon atoms. ] The insulating film according to any one of claims 1 to 3, wherein the acid generator (B1) is a compound represented by the following general formula (b1) or a compound represented by the following general formula (b2). Forming photosensitive composition.

[Wherein, Rb ^{1 to} Rb ⁵ each independently represents an aryl group, an alkyl group or an alkenyl group which may have a substituent, and Rb ^{1 to} Rb ³ are bonded to each other to form You may form a ring with a sulfur atom. However, Rb ^{1 to} Rb ³ have only one aromatic ring as a whole or no aromatic ring. Rb ^{4 to} Rb ⁵ have only one aromatic ring as a whole or no aromatic ring. A ⁻ represents a counter anion. ]   The photosensitive composition for insulating film formation as described in any one of Claims 1-4 whose mass average molecular weights of the said silsesquioxane resin (A) are 1000-5000.   The content ratio (molar ratio) of the structural unit (a1) and the structural unit (a2) is structural unit (a1) / structural unit (a2) = 40/60 to 90/10. The photosensitive composition for insulating film formation as described in any one of these.   Furthermore, the photosensitive composition for insulating film formation as described in any one of Claims 1-6 containing a nitrogen-containing organic compound (D).   A film forming step of forming a film on a support using the photosensitive composition for forming an insulating film according to any one of claims 1 to 7, an exposure step of selectively exposing the film, and the exposure An insulating film pattern forming method comprising: a developing step of developing a subsequent film to form a prepattern; and a curing step of curing the prepattern to obtain an insulating film pattern.   The method for forming an insulating film pattern according to claim 8, wherein the film formed in the film forming step has a thickness of 700 nm or more.