WO2018194123A1

WO2018194123A1 - Radiation-sensitive resin composition and resist pattern formation method

Info

Publication number: WO2018194123A1
Application number: PCT/JP2018/016125
Authority: WO
Inventors: 康太古市; 聡司岡嵜
Original assignee: Jsr株式会社
Priority date: 2017-04-20
Filing date: 2018-04-19
Publication date: 2018-10-25
Also published as: TWI763827B; JPWO2018194123A1; TW201843198A

Abstract

The present invention is a radiation-sensitive resin composition containing a first polymer having structural units including an acid-dissociable group, a first compound generated by radiating radioactive rays onto a first acid that dissociates the acid-dissociable group in one minute at 110ºC, and a second compound generated by radiating radioactive rays onto a second acid that does not substantially dissociate the acid-dissociable group in one minute at 110ºC, the first compound content being at least 10% by mass of the total solid content (all non-solvent components in the composition), and the ratio Bm/Cm being at least 1.7, where Bm is the number of moles of the first compound and Cm is the number of moles of the second compound.

Description

Radiation-sensitive resin composition and resist pattern forming method

The present invention relates to a radiation-sensitive resin composition and a resist pattern forming method.

With the miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, further miniaturization of resist patterns in the lithography process is required, and various radiation-sensitive resin compositions are being studied. Such a radiation sensitive resin composition generates an acid in an exposed part by irradiation with exposure light such as deep ultraviolet light such as ArF excimer laser light, extreme ultraviolet light (EUV), electron beam (EB), and the like. The action causes a difference in the dissolution rate of the exposed portion and the unexposed portion with respect to the developer, thereby forming a resist pattern on the substrate.

Such a radiation sensitive resin composition not only has excellent resolution, but also has excellent CDU (Critical Dimension Uniformity) performance in hole pattern formation and LWR (Line Width Roughness) performance in line and space pattern formation, as well as depth of focus. (It is required to be excellent in DOF (Depth Of Focus) and to obtain a high-accuracy pattern with high yield. In response to this requirement, various components contained in the radiation-sensitive resin composition have been studied. (For example, see JP-A-11-212265, JP-A-2003-5375, and JP-A-2008-83370).

JP-A-11-212265 JP 2003-5375 A JP 2008-83370 A

The present invention has been made based on the circumstances as described above, and an object thereof is to provide a radiation-sensitive resin composition and a resist pattern forming method that are excellent in CDU performance, LWR performance, resolution, and depth of focus. There is.

The invention made in order to solve the above-mentioned problems is a first polymer having a structural unit containing an acid dissociable group (hereinafter also referred to as “acid dissociable group (a)”) (hereinafter referred to as “[A] polymer”). And a first compound that generates the first acid that dissociates the acid-dissociable group (a) at 110 ° C. for 1 minute by irradiation with radiation (hereinafter, also referred to as “[B] compound”). And a second compound (hereinafter also referred to as “[C] compound”) that generates a second acid that does not substantially dissociate the acid dissociable group (a) at 110 ° C. for 1 minute. The content of the [B] compound is 10% by mass or more in the total solid content (all components other than the solvent in the composition), the number of moles of the [B] compound is B _m , and the above [C ] the number of moles of the compound when the C _m, with a radiation-sensitive resin composition B m _/ C _m is 1.7 or more That.

Another invention made in order to solve the above-described problems is a step of coating the radiation-sensitive resin composition on at least one surface side of a substrate, and exposing a resist film formed by the coating step. A method for forming a resist pattern comprising a step and a step of developing the exposed resist film.

According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, a resist pattern having a wide depth of focus, small CDU and LWR, and high resolution can be formed. Accordingly, these can be suitably used for semiconductor device processing processes and the like that are expected to be further miniaturized in the future.

<Radiation sensitive resin composition>
The radiation-sensitive resin composition contains a [A] polymer, a [B] compound, and a [C] compound. The radiation-sensitive resin composition contains a fluorine atom and / or a silicon atom as a suitable component, and the sum of the mass content of the fluorine atom and the mass content of the silicon atom is [A] fluorine atom in the polymer. May contain a second polymer (hereinafter also referred to as “[D] polymer”) and / or a solvent [E] which is larger than the sum of the mass content and the silicon mass content. In the range which does not impair the effect of, other optional components may be contained.

Examples of the radiation sensitive resin composition include a radiation sensitive resin composition (I) for KrF or ArF exposure, and a radiation sensitive resin composition (II) for EUV or EB exposure. The radiation sensitive resin composition (I) is particularly suitable for ArF exposure.

The polymer contained in the radiation sensitive resin composition (I) usually does not have an aromatic ring including a structural unit (IV) containing a phenolic hydroxyl group described later. In the radiation sensitive resin composition (II), the [A] polymer has a structural unit (IV) containing a phenolic hydroxyl group. In the present specification, the “phenolic hydroxyl group” is not limited to those directly bonded to a benzene ring, but refers to all hydroxy groups directly bonded to an aromatic ring.

The radiation-sensitive resin composition contains a [A] polymer, a [B] compound, and a [C] compound, the content of the [B] compound is set to the above value or more, and the number of moles of the [B] compound (B moles of [C] compounds of _m) the (ratio _{C m)} _(B m / _{C m)} by the above said value, CDU performance, LWR performance, resolution and depth of focus (hereinafter, "CDU performance Etc.)). The reason why the radiation-sensitive resin composition exhibits the above-described effect by having the above-described configuration is not necessarily clear, but for example, while increasing the content of the [B] compound to the above-described constant value or more, C] The molar ratio of the compound to the [B] compound is set to a certain value or less, thereby maintaining the exposure light absorption amount of the resist film to be formed at a certain value or less, thereby reducing the exposure intensity distribution in the resist film. It can be made more appropriate, and CDU performance and the like can be improved. Hereinafter, each component will be described.

<[A] polymer>
[A] The polymer is a polymer having a structural unit containing an acid dissociable group (a) (hereinafter also referred to as “structural unit (I)”). [A] In addition to the structural unit (I), the polymer is a structural unit (II) containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof, a structural unit (III) containing an alcoholic hydroxyl group, and / or phenol. It preferably has a structural unit (IV) containing a functional hydroxyl group, and may have other structural units other than the structural units (I) to (IV). [A] The polymer may have one or more of each structural unit. Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) is a structural unit containing an acid dissociable group (a). Here, the “acid-dissociable group” refers to a group that replaces a hydrogen atom of an acidic group such as a carboxy group, a hydroxy group, or a sulfo group, and that dissociates by the action of an acid. [A] Since the polymer has the structural unit (I), the acid dissociable group (a) in the exposed portion is dissociated by the action of an acid generated from the [B] compound, and the polarity is changed. On the other hand, a resist pattern can be formed by being easily soluble or hardly soluble.

As the acid dissociable group (a), for example, a group represented by the following formula (PG1) bonded to an oxyoxygen atom derived from a carboxy group or a sulfo group (hereinafter also referred to as “group (I-1)”), And a group represented by the following formula (PG2) bonded to an oxyoxygen atom derived from a carboxy group, a sulfo group or a hydroxy group (hereinafter also referred to as “group (I-2)”).

In the above formula (PG1), ^RPG1 is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^PG2 and R ^PG3 are each independently a monovalent linear or branched chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. Or part of an alicyclic structure of 3 to 20 ring members composed of these groups together with the carbon atom to which they are attached. * Shows the site | part couple | bonded with the oxy oxygen atom originating in a carboxy group or a sulfo group.

In the above formula (PG2), R ^PG4 and R ^PG5 each independently represent a hydrogen atom, a monovalent linear or branched chain hydrocarbon group having 1 to 20 carbon atoms, or 3 to 20 carbon atoms. R ^PG6 represents a monovalent linear or branched chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent fatty acid having 3 to 20 carbon atoms. or a cyclic hydrocarbon ^radical, or is a part of the alicyclic structure ^{R PG4} and ^{R PG5} are combined together constituted with the carbon atoms to which they are attached ring members 3-20, or ^{R PG4} and ^{R PG6} There is a part of the aliphatic heterocyclic structure consisting ring members 5-20 together with oxygen atom to the carbon atom and R ^PG6 which R ^PG4 are attached are combined to bind to each other. ** represents a site bonded to an oxyoxygen atom derived from a carboxy group, a sulfo group or a hydroxy group.

The “hydrocarbon group” includes a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The “hydrocarbon group” may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The “chain hydrocarbon group” refers to a hydrocarbon group that does not include a cyclic structure and is composed only of a chain structure, and includes both a straight chain hydrocarbon group and a branched chain hydrocarbon group. The term “alicyclic hydrocarbon group” refers to a hydrocarbon group that includes only an alicyclic structure as a ring structure and does not include an aromatic ring structure, and includes a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Includes both hydrocarbon groups. However, it is not necessary to be composed only of the alicyclic structure, and a part thereof may include a chain structure. “Aromatic hydrocarbon group” refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessary to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic structure. “Number of ring members” means the number of atoms constituting the ring of the alicyclic structure, aromatic ring structure, aliphatic heterocyclic structure and aromatic heterocyclic structure, and in the case of polycyclic, the number of atoms constituting this polycyclic ring Say.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by ^RPG1 include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent alicyclic carbon group having 3 to 20 carbon atoms. Examples thereof include a hydrogen group and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

^Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms represented by R ^PG1 to R ^PG6 include linear hydrocarbon groups such as a methyl group, an ethyl group, an n-propyl group, and an n-butyl group. ;
Examples thereof include branched hydrocarbon groups such as i-propyl group, 2-methylpropyl group, 1-methylpropyl group and t-butyl group.

^Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ^PG1 to R ^PG6 include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a norbornyl group, an adamantyl group, a tricyclo group. An alicyclic saturated hydrocarbon group such as a decyl group or a tetracyclododecyl group;
Examples thereof include alicyclic unsaturated hydrocarbon groups such as cyclopentenyl group, cyclohexenyl group, cyclooctenyl group, cyclodecenyl group, norbornenyl group, tricyclodecenyl group, and tetracyclododecenyl group.

The alicyclic structure R ^PG2 and ^{R PG3} and ^{R PG4} and ^{R PG5} consists membered rings 3-20 with keyed carbon atom to which they are attached to each other, such as cyclopentane structure, a cyclohexane structure, a cycloheptane structure, cyclo Examples include an octane structure, a norbornane structure, an adamantane structure, a tricyclodecane structure, and a tetracyclododecane structure.

The aliphatic heterocyclic structure R ^PG4 and configured with an oxygen atom to the carbon atom and ^{R PG6} ^{which R PG6} is keyed ^{R PG4} are bonded to each other are attached ring members 5-20, for example oxacyclopentane structure, oxacyclohexane Examples include a structure, an oxacycloheptane structure, an oxacyclooctane structure, and an oxanorbornane structure.

^RPG6 may be combined with the main chain side portion of the acidic group to which the group (I-2) is bonded and may represent a ring structure having 5 to 20 ring members together with the atomic chain to which these groups are bonded. Examples of such a structure include a group having a cyclic acetal structure.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by ^RPG1 include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and an anthryl group;
Examples thereof include aralkyl groups such as benzyl group, phenethyl group, and naphthylmethyl group.

Examples of the structural unit (I) include a structural unit derived from a (meth) acrylic acid ester containing an acid dissociable group (a), a structural unit derived from a methylene group-containing lactone containing an acid dissociable group (a), and an acid. Examples thereof include a structural unit derived from styrene containing a dissociable group (a). When KrF excimer laser light, EUV, EB, or the like is used as the radiation irradiated in the exposure step in the resist pattern forming method, a structural unit derived from styrene containing an acid dissociable group (a) is used as the structural unit (I). By having it, the sensitivity can be further increased, and as a result, the CDU performance and the like of the radiation-sensitive resin composition can be further improved.

The lower limit of the content ratio of the structural unit (I) is preferably 10 mol%, more preferably 30 mol%, and even more preferably 40 mol% with respect to all the structural units constituting the [A] polymer. As an upper limit of the said content rate, 80 mol% is preferable, 70 mol% is more preferable, and 60 mol% is further more preferable. By making the content rate of structural unit (I) into the said range, the sensitivity of the said radiation sensitive resin composition can be made moderate, As a result, CDU performance etc. can be improved more.

[Structural unit (II)]
The structural unit (II) is a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof (except for those corresponding to the structural unit (I)). [A] By having the structural unit (II), the polymer can adjust the solubility in the developer more appropriately, and as a result, the CDU performance and the like of the radiation-sensitive resin composition are further improved. be able to. In addition, the adhesion between the resist pattern and the substrate can be further improved.

Examples of the structural unit (II) include a structural unit represented by the following formula.

In the above formula, R ^L1 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

The structural unit (II) is preferably a structural unit containing a lactone structure.

[A] When the polymer has the structural unit (II), the lower limit of the content ratio of the structural unit (II) is preferably 10 mol%, preferably 15 mol% with respect to all the structural units in the polymer. Is more preferable, 20 mol% is further more preferable, and 25 mol% is particularly preferable. As an upper limit of the said content rate, 80 mol% is preferable, 70 mol% is more preferable, 60 mol% is further more preferable, 55 mol% is especially preferable. By setting the content ratio of the structural unit (II) in the above range, the [A] polymer can further appropriately adjust the solubility in the developer, and as a result, the CDU of the radiation-sensitive resin composition can be adjusted. The performance and the like can be further improved. Further, the adhesion between the resist pattern and the substrate can be further improved.

[Structural unit (III)]
The structural unit (III) is a structural unit containing an alcoholic hydroxyl group (except for those corresponding to the structural unit (I)). [A] By having the structural unit (III), the polymer can adjust the solubility in the developer more appropriately, and as a result, the CDU performance and the like of the radiation sensitive resin composition are further improved. be able to. In addition, the adhesion between the resist pattern and the substrate can be further improved.

Examples of the structural unit (III) include a structural unit represented by the following formula.

In the above formula, R ^L2 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[A] When the polymer has the structural unit (III), the lower limit of the content ratio of the structural unit (III) is preferably 1 mol% with respect to all the structural units in the polymer [A], and 5 mol%. Is more preferable. As an upper limit of the said content rate, 30 mol% is preferable and 20 mol% is more preferable. By setting the content ratio of the structural unit (III) in the above range, the [A] polymer can further appropriately adjust the solubility in the developer, and as a result, the CDU of the radiation-sensitive resin composition can be adjusted. The performance and the like can be further improved. Further, the adhesion between the resist pattern and the substrate can be further improved.

[Structural unit (IV)]
The structural unit (IV) is a structural unit containing a phenolic hydroxyl group (except for those corresponding to the structural unit (I)). When KrF excimer laser light, EUV, EB, or the like is used as the radiation to be irradiated in the exposure process in the resist pattern forming method, the sensitivity can be further increased by the [A] polymer having the structural unit (IV). As a result, the CDU performance and the like of the radiation sensitive resin composition can be further improved.

Examples of the structural unit (IV) include a structural unit represented by the following formula (1).

In said formula (1), ^RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y is a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms, —CO—, —SO ₂ —, —O—, —NH—, or a combination thereof, or a single bond. R ^B is a halogen atom or a monovalent organic group having 1 to 20 carbon atoms. p is an integer of 0-2. a is an integer of 0 to 8. b is an integer of 1 to 9. However, a + b is 9 or less. When a is 2 or more, the plurality of R ^B are the same or different from each other.

R ^A is preferably a hydrogen atom or a methyl group from the viewpoint of copolymerization of the monomer that gives the structural unit (IV).

Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms represented by Y include a group obtained by removing one hydrogen atom from the monovalent hydrocarbon group exemplified as R ^{PG1 in the} above formula (PG1). Can be mentioned. Examples of the substituent for the divalent hydrocarbon group include a hydroxy group and a halogen atom.

Y is preferably a single bond, —O—, —COO— or —CONH—, more preferably a single bond or —COO—.

“Organic group” refers to a group containing at least one carbon atom. The monovalent organic group having 1 to 20 carbon atoms represented by R ^B, for example, monovalent hydrocarbon group having 1 to 20 carbon atoms, the carbon of the hydrocarbon group - the terminal carbon-carbon or a bond side A monovalent group (g) containing a divalent heteroatom-containing group, a monovalent group obtained by substituting a part or all of the hydrogen atoms of the hydrocarbon group and group (g) with a heteroatom-containing group, and the like. It is done.

R ^B is preferably a monovalent hydrocarbon group, more preferably an alkyl group, and even more preferably a methyl group.

P is preferably 0 or 1, more preferably 0. As a, 0 or 1 is preferable, and 0 is more preferable. As b, 1 or 2 is preferable and 1 is more preferable.

[A] When a polymer has a structural unit (IV), as a minimum of the content rate of a structural unit (IV), 10 mol% is preferable with respect to all the structural units in a [A] polymer, and 20 mol% Is more preferable. As an upper limit of the said content rate, 80 mol% is preferable and 60 mol% is more preferable. By making the content rate of structural unit (IV) into the said range, [A] polymer can improve a sensitivity more, As a result, further improving the CDU performance of the said radiation sensitive resin composition, etc. Can do.

[Other structural units]
Examples of the other structural unit include a structural unit (V) containing a non-acid-dissociable hydrocarbon group (however, even if it is a structural unit containing a non-acid-dissociable hydrocarbon group, a separate acid unit). Those having a dissociable group are classified as structural unit (I) in this specification). Examples of the non-acid-dissociable hydrocarbon group include a methyl group bonded to the —COO—oxy group, a primary or secondary chain hydrocarbon group, a secondary alicyclic hydrocarbon group, and adamantane-1- Yl group and the like. [A] When a polymer has other structural units, as a minimum of the content rate of other structural units, it is 1 mol%, for example. As an upper limit of the said content rate, 30 mol% is preferable and 20 mol% is more preferable.

[A] The lower limit of the content of the polymer is preferably 40% by mass, more preferably 45% by mass, and 50% by mass when the total solid content of the radiation-sensitive resin composition is 100% by mass. More preferred is 80% by mass. The “total solid content” of the radiation-sensitive resin composition refers to all components other than the [E] solvent. The said radiation sensitive resin composition can contain 1 type (s) or 2 or more types of [A] polymers.

[A] The polymer can be synthesized, for example, by polymerizing monomers giving each structural unit by a known method.

[A] The lower limit of the weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is preferably 1,000, more preferably 3,000, still more preferably 5,000, 000 is particularly preferred. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 15,000. [A] By making Mw of a polymer into the said range, the applicability | paintability of the said radiation sensitive resin composition can be improved, As a result, CDU performance etc. can be improved more.

[A] The upper limit of the ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer is preferably 5, more preferably 3, more preferably 2, and particularly preferably 1.5 . The lower limit of the ratio is usually 1 and preferably 1.1.

Mw and Mn of the polymer in this specification are values measured using gel permeation chromatography (GPC) under the following conditions.
GPC column: 2 "G2000HXL" from Tosoh Corporation, 1 "G3000HXL" and 1 "G4000HXL" Column temperature: 40 ° C
Elution solvent: Tetrahydrofuran (Wako Pure Chemical Industries)
Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Detector: Differential refractometer Standard material: Monodisperse polystyrene

<[B] Compound>
The compound [B] is a compound that generates a first acid (hereinafter also referred to as “acid (B)”) that dissociates the acid dissociable group (a) at 110 ° C. for 1 minute by irradiation with radiation. .

As the acid (B), for example, in the case of the radiation sensitive resin composition (I), a sulfonic acid containing a fluorine atom (hereinafter also referred to as “acid (B1-1)”), a disulfonylimide acid containing a fluorine atom ( Hereinafter, also referred to as “acid (B1-2)”, sulfomalonic acid ester (hereinafter also referred to as “acid (B1-3)”), etc.
In the case of the radiation sensitive resin composition (II), sulfonic acid (hereinafter also referred to as “acid (B2-1)”), disulfonylimide acid (hereinafter also referred to as “acid (B2-2)”), and the like can be mentioned. It is done.

Examples of the acid (B1-1) include a compound represented by the following formula (2-1).

In the above formula (2-1), R ^C is a monovalent organic group having 1 to 30 carbon atoms. R ^D1 and R ^D2 are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. n is 1 or 2. When n is 2, 2 R ^D1 are the same or different from each other, and 2 R ^D2 are the same or different from each other. However, at least one of R ^D1 and R ^D2 is a fluorine atom or a fluorinated hydrocarbon group.

Examples of the acid (B1-2) include compounds represented by the following formula (2-2).

In the above formula (2-2), R ^E1 and R ^E2 are each independently a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, or these groups are combined with each other to form the formula (2 -2) A part of a ring structure having 6 to 12 ring members, which is formed together with the sulfur atom and the nitrogen atom.

Examples of the acid (B1-3) include compounds represented by the following formula (2-3).

In the above formula (2-3), R ^F1 and R ^F2 are each independently a monovalent organic group having 1 to 20 carbon atoms, or these groups are combined with each other to form the formula (2-3) It is a part of a ring structure having 7 to 12 ring members that is formed together with —O—CO—CH—CO—O—.

Examples of the acid (B2-1) include a compound represented by the following formula (3-1).

In the above formula (3-1), R ^G is a monovalent organic group having 1 to 30 carbon atoms.

Examples of the acid (B2-2) include compounds represented by the following formula (3-2).

In the above formula (3-2), R ^H1 and R ^H2 are each independently a monovalent organic group having 1 to 20 carbon atoms, or these groups are combined with each other to form the formula (3-2) It is a part of a ring structure having 6 to 12 ring members, which is composed of a sulfur atom and a nitrogen atom.

Examples of the monovalent organic group represented by R ^C , R ^F1 , R ^F2 , R ^G , R ^H1 and R ^H2 are the same groups as those exemplified as the organic group for R ^{B in} the above formula (1). Etc.

Examples of the monovalent hydrocarbon group represented by R ^D1 and R ^D2 include the same groups as those exemplified as the hydrocarbon group of R ^{PG1 in} the above formula (PG1). Among these, an alkyl group is preferable and a methyl group is more preferable.

As the monovalent fluorinated hydrocarbon group represented by R ^D1 , R ^D2 , R ^E1 and R ^E2 , for example, a part of hydrogen atoms possessed by the hydrocarbon group exemplified as R ^{PG1 in the} above formula (PG1) or Examples include groups in which all are substituted with fluorine atoms. Among these, a perfluoroalkyl group is preferable and a trifluoromethyl group is more preferable.

The acid (B) preferably has a ring structure having 5 to 20 ring members. When the acid (B) has such a ring structure, the diffusion length of the acid (B) in the resist film can be shortened more appropriately. As a result, the CDU performance of the radiation-sensitive resin composition can be reduced. Etc. can be further improved. Examples of such a ring structure include an alicyclic structure such as a norbornane structure and an adamantane structure; an aromatic ring structure such as a benzene structure and a fluorene structure.

[B] The compound is usually a salt of a radiation-sensitive cation and an anion obtained by removing a proton from the acid group of the acid (B) (hereinafter also referred to as “anion (B)”). In the exposed area, the [B] compound gives an acid (B) from protons and anions (B) generated by the decomposition of the radiation-sensitive anion by the action of radiation. According to this acid (B), the acid dissociable group (a) of the [A] polymer can be dissociated at 110 ° C. for 1 minute. That is, the [B] compound functions as an acid generator that dissociates the acid dissociable group of the [A] polymer in the exposed area and changes the solubility in the developer.

Examples of the anion (B) include a sulfonate anion containing a fluorine atom that gives an acid (B1-1) and a disulfonylimide containing a fluorine atom that gives an acid (B1-2) in the case of the radiation sensitive resin composition (I). An anion having a sulfonate group bonded to a methylene carbon atom of a malonate group that gives an acid (B1-3), etc.
In the case of the radiation sensitive resin composition (II), a sulfonate anion that gives an acid (B2-1), a disulfonylimide anion that gives an acid (B2-2), and the like.

The radiation-sensitive cation is a cation that is decomposed by exposure light and / or electron beam irradiation. Taking an acid generator composed of a sulfonate anion and a radiation-sensitive onium cation as an example, in the exposed portion, a sulfonic acid is generated from protons generated by the decomposition of the radiation-sensitive onium cation and the sulfonate anion.

Examples of the monovalent radiation-sensitive onium cation include a cation represented by the following formula (r−a) (hereinafter also referred to as “cation (r−a)”), and a valence represented by the following formula (rb). Cation (hereinafter also referred to as “cation (r−b)”), a cation represented by the following formula (rc) (hereinafter also referred to as “cation (rc)”), and the like.

In the above formula (r−a), R ^B3 and R ^B4 are each independently a monovalent organic group having 1 to 20 carbon atoms. b3 is an integer of 0 to 11. When b3 is 1, R ^B5 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom. when b3 is 2 or more, the plurality of R ^B5 are the same or different from each other and are each a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom, or these groups are combined with each other Is a part of a ring structure having 4 to 20 ring members constituted with a carbon chain to which is bonded. n _bb is an integer of 0 to 3.

The monovalent organic group of the ^R ^{B3, R B4} and having 1 to 20 carbon atoms represented by ^{R B5,} for example, like same groups as exemplified organic groups as ^{R B} in the formula (1).

R ^B3 and R ^B4 are preferably a monovalent unsubstituted hydrocarbon group having 1 to 20 carbon atoms or a hydrocarbon group in which a hydrogen atom of these groups is substituted with a substituent, and has 6 to 18 carbon atoms. A monovalent unsubstituted aromatic hydrocarbon group or an aromatic hydrocarbon group in which the hydrogen atom of these groups is substituted with a substituent is more preferred, and a substituted or unsubstituted phenyl group is more preferred.

Examples of the substituent which may be substituted on the hydrogen atom of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^B3 and R ^B4 include substituted or unsubstituted 1 to 20 carbon atoms. Valent hydrocarbon group, —OSO ₂ —R ^k , —SO ₂ —R ^k , —OR ^k , —COOR ^k , —O—CO—R ^k , —O—R ^kk —COOR ^k , —R ^kk —CO -R ^k, or ^{-S-R k} are preferred. R ^k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

R ^B5 includes a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, —OSO ₂ —R ^k , —SO ₂ —R ^k , —OR ^k , —COOR ^k , —O—CO— R ^k , —O—R ^kk —COOR ^k , —R ^kk —CO—R ^k or —S—R ^k is preferred. R ^k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

In the above formula (rb), b4 is an integer of 0 to 9. When b4 is 1, R ^B6 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom. When b4 is 2 or more, the plurality of R ^B6 are the same or different from each other, and are each a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom, or these groups are combined with each other Is a part of a ring structure having 4 to 20 ring members constituted with a carbon chain to which is bonded. b5 is an integer of 0 to 10. When b5 is 1, R ^B7 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom. When b5 is 2 or more, the plurality of R ^B7 are the same or different from each other, and are each a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom, or these groups are combined with each other Is a part of a ring structure having 3 to 20 ring members constituted with a carbon atom or a carbon chain to which is bonded. n _b2 is an integer of 0 to 3. R ^B8 is a single bond or a divalent organic group having 1 to 20 carbon atoms. n _b1 is an integer of 0-2.

R ^B6 and R ^B7 include a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, —OR ^k , —COOR ^k , —O—CO—R ^k , —O—R ^kk —COOR. ^k or —R ^kk —CO—R ^k is preferred. R ^k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

Examples of R ^B8 include a group in which one hydrogen atom is removed from a monovalent organic group having 1 to 20 carbon atoms exemplified as R ^{B in the} above formula (1).

In the above formula (rc), b6 is an integer of 0 to 5. When b6 is 1, R ^B9 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom. when b6 is 2 or more, the plurality of R ^B9 are the same or different from each other, and are each a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom, or these groups are combined with each other Is a part of a ring structure having 4 to 20 ring members constituted with a carbon chain to which is bonded. b7 is an integer of 0 to 5. When b7 is 1, R ^B10 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom. When b7 is 2 or more, the plurality of R ^B10 are the same or different from each other, and are each a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom, or these groups are combined with each other Is a part of a ring structure having 4 to 20 ring members constituted with a carbon chain to which is bonded.

R ^B9 and R ^B10 include a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, —OSO ₂ —R ^k , —SO ₂ —R ^k , —OR ^k , —COOR ^k , — A ring structure in which two or more of O—CO—R ^k , —O—R ^kk —COOR ^k , —R ^kk —CO—R ^k , —S—R ^k or these groups are combined with each other preferable. R ^k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^B5 , R ^B6 , R ^B7 , R ^B9 and R ^B10 include the groups exemplified as the hydrocarbon group of R ^{PG1 in} the above formula (PG1). And the like groups.

Examples of the divalent organic group represented by R ^B8 include groups in which one hydrogen atom has been removed from a monovalent organic group having 1 to 20 carbon atoms exemplified as R ^{A in the} above formula (1). It is done.

Examples of the substituent that may substitute the hydrogen atom of the hydrocarbon group represented by R ^B5 , R ^B6 , R ^B7 , R ^B9, and R ^B10 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. And a halogen atom such as hydroxy group, carboxy group, cyano group, nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, and acyloxy group. Among these, a halogen atom is preferable and a fluorine atom is more preferable.

R ^B5 , R ^B6 , R ^B7 , R ^B9, and R ^B10 include an unsubstituted linear or branched alkyl group, a fluorinated alkyl group, an unsubstituted monovalent aromatic hydrocarbon group, —OSO ₂ -R ^k, or -SO ₂ -R ^k, more preferably a fluorinated alkyl group or an unsubstituted monovalent aromatic hydrocarbon group, more preferably a fluorinated alkyl group.

As b3 in the formula (r−a), an integer of 0 to 2 is preferable, 0 or 1 is more preferable, and 0 is more preferable. As n _bb , 0 or 1 is preferable, and 0 is more preferable. In the formula (rb), b4 is preferably an integer of 0 to 2, more preferably 0 or 1, and still more preferably 0. b5 is preferably an integer of 0 to 2, more preferably 0 or 1, and still more preferably 0. As _nb2 , 2 or 3 is preferable and 2 is more preferable. As n _b1 , 0 or 1 is preferable, and 0 is more preferable. In formula (rc), b6 and b7 are preferably integers of 0 to 2, more preferably 0 or 1, and still more preferably 0.

Among these monovalent radiation-sensitive onium cations, cation (r−a) or cation (r−b) is preferable, and triphenylsulfonium cation or 1- [2- (4-cyclohexylphenylcarbonyl) is preferable. Propan-2-yl] tetrahydrothiophenium cation is more preferred.

Examples of the compound [B] include compounds represented by the following formulas (i-1) to (i-6) (hereinafter also referred to as “compounds (i-1) to (i-6)”). .

In the above formulas (i-1) to (i-6), T ⁺ is a monovalent radiation-sensitive onium cation.

[B] Compounds (i-1) to (i-6) are preferred as the compound.

The lower limit of the content of the [B] compound is 10% by mass, preferably 11% by mass, and more preferably 12% by mass in the total solid content (all components other than the [E] solvent in the composition). As an upper limit of the said content, 20 mass% is preferable, 15 mass% is more preferable, and 14 mass% is further more preferable. [B] By making content of a compound into the said range, the sensitivity of the said radiation sensitive resin composition can be raised more appropriately, As a result, CDU performance etc. can be improved more. The radiation-sensitive resin composition can contain one or more [B] compounds.

<[C] Compound>
The compound [C] generates a second acid (hereinafter also referred to as “acid (C)”) that does not substantially dissociate the acid dissociable group (a) at 110 ° C. for 1 minute by irradiation with radiation. A compound. “The acid dissociable group is not substantially dissociated” means that the dissociation rate of the acid dissociable group under the above conditions is 5 mol% or less.

As the acid (C), for example, in the case of the radiation sensitive resin composition (I), for example, a sulfonic acid containing no fluorine atom (excluding sulfomalonic acid ester) (hereinafter also referred to as “acid (C1-1)”), Examples thereof include carboxylic acid (hereinafter also referred to as “acid (C1-2)”), sulfonamidic acid (hereinafter also referred to as “acid (C1-3)”), and the like.
In the case of the radiation sensitive resin composition (II), carboxylic acid (hereinafter also referred to as “acid (C2-1)”), sulfonamidic acid (hereinafter also referred to as “acid (C2-2)”), and the like can be mentioned. .

Examples of the acid (C1-1) include compounds represented by the following formula (4-1).

In the above formula (4-1), R ^S1 , R ^S2 and R ^S3 are each independently a monovalent organic group having 1 to 30 carbon atoms which does not contain a hydrogen atom or a fluorine atom, or these Two or more of the groups are part of a ring structure having 3 to 20 ring members that is configured together with the carbon atoms to which they are attached. However, two or more of R ^S1 , R ^S2 and R ^S3 are not R′—O—CO— (where R ′ is a monovalent organic group having 1 to 29 carbon atoms).

Examples of the acid (C1-2) and the acid (C2-1) include compounds represented by the following formula (4-2).

In the above formula (4-2), ^RT is a monovalent organic group having 1 to 30 carbon atoms.

Examples of the acid (C1-3) and the acid (C2-2) include compounds represented by the following formula (4-3).

In the above formula (4-3), ^{R U} represents a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R ^V is a monovalent organic group having 1 to 20 carbon atoms.

Examples of the monovalent organic group that does not contain a fluorine atom represented by R ^S1 , R ^S2, and R ^S3 include those that do not contain a fluorine atom among the groups exemplified as the organic group of R ^{B in} the above formula (1). Etc.

Examples of the ring structure having 3 to 20 ring members constituted by two or more of R ^S1 , R ^S2 and R ^S3 include alicyclic structures such as norbornane structure and adamantane structure; aromatic rings such as benzene structure and fluorene structure Examples include the structure.

Examples of the monovalent organic group represented by R ^T and R ^V include the same groups as those exemplified as the organic group of R ^{B in} the above formula (1).

Examples of the monovalent fluorinated hydrocarbon groups represented by R ^U, for example, the radical obtained by substituting a part or all of the hydrogen atoms by fluorine atoms included in the exemplified hydrocarbon groups as R ^PG1 of (PG1), etc. Is mentioned. Among these, a perfluoroalkyl group is preferable and a trifluoromethyl group is more preferable.

The acid (C) preferably has a ring structure having 5 to 20 ring members. Since the acid (C) has such a ring structure, the diffusion of the acid (C) in the resist film can be further suppressed, and as a result, the CDU performance and the like of the radiation sensitive resin composition can be further improved. Can be improved. Examples of such a ring structure include an alicyclic structure such as a norbornane structure and an adamantane structure; an aromatic ring structure such as a benzene structure and a fluorene structure.

[C] The compound is usually a salt of a radiation-sensitive cation and an anion obtained by removing a proton from the acid group of the acid (C) (hereinafter also referred to as “anion (C)”). The compound [C] may have a betaine structure in which a group derived from an anion (C) such as a carboxylate group is bonded to a hydrocarbon group or the like of a radiation-sensitive cation.

In the exposed area, the [C] compound gives an acid (C) from a proton and an anion (C) generated by the decomposition of the radiation sensitive anion by the action of radiation. This acid (C) does not substantially dissociate the acid dissociable group (a) at 110 ° C. for 1 minute. Therefore, the [C] compound exhibits a function as an acid diffusion controller in the resist film.

As the anion (C), for example, in the case of the radiation-sensitive resin composition (I), a sulfonate anion containing no fluorine atom that gives the acid (C1-1) (excluding an anion derived from sulfomalonic acid ester), an acid (C1 -2) a carboxylate anion that gives acid, a sulfonamidate anion that gives acid (C1-3), etc.
In the case of the radiation sensitive resin composition (II), a carboxylate anion that gives an acid (C2-1), a sulfonamidate anion that gives an acid (C2-2), and the like can be mentioned.

Examples of the radiation sensitive cation of the [C] compound include the same cations as those exemplified as the radiation sensitive cation of the above [B] compound.

Examples of the compound [C] include compounds represented by the following formulas (ii-1) to (ii-8) (hereinafter also referred to as “compounds (ii-1) to (ii-8)”). .

In the above formulas (ii-1) to (ii-7), T ⁺ is a monovalent radiation-sensitive onium cation.

[C] Compounds (ii-1) to (ii-6) are preferred as the [C] compound.

When the [C] compound contains a nitrogen atom, the acid diffusion control ability is improved, while a part of the acid generated from the [B] compound is captured in the exposed area, so that there is a difference in acid concentration from the unexposed area. The difference in solubility (dissolution contrast) in the developer between the exposed area and the unexposed area becomes smaller. When it is desired to increase the dissolution contrast, the [C] compound is preferably a compound containing no nitrogen atom.

[C] The lower limit of the content of the compound is preferably 0.1% by mass, more preferably 1% by mass, and preferably 1.5% by mass in the total solid content (all components other than the solvent [E] in the composition). % Is more preferable, and 2% by mass is particularly preferable. As an upper limit of the said content, 10 mass% is preferable, 8 mass% is more preferable, 7.5 mass% is further more preferable, 7 mass% is especially preferable. By making content of a [C] compound into the said range, CDU performance of the said radiation sensitive resin composition etc. can be improved more.

[C] The lower limit of the content of the compound is preferably 0.1 parts by mass, more preferably 1 part by mass, further preferably 1.5 parts by mass, with respect to 100 parts by mass of the polymer [A]. Part is particularly preferred. As an upper limit of the said content, 12 mass parts is preferable, 10 mass parts is more preferable, 9 mass parts is further more preferable, and 8 mass parts is especially preferable. The radiation-sensitive resin composition can contain one or more [C] compounds.

[B] the number of moles of compound _B m, when the number of moles of [C] compounds and _{C _m,} the lower limit of B _{m /} C m (ratio _{C m} of _{B m),} be 1.7 2.0 is preferable, 2.6 is more preferable, 3.0 is more preferable, and 3.2 is particularly preferable. The upper limit of the above B _m / C _m is preferably 10, more preferably 5, more preferably 4, and particularly preferably 3.5. By making said _Bm / _Cm into the said range, CDU performance of the said radiation sensitive resin composition etc. can be improved more.

The lower limit of the total content of the [B] compound and the [C] compound is preferably 10.1% by mass and 12% by mass in the total solid content (all components other than the solvent [E] in the composition). More preferred is 14% by mass. As an upper limit of the said total content, 30 mass% is preferable, 20 mass% is more preferable, and 18 mass% is further more preferable. By setting the total content of the [B] compound and the [C] compound in the above range, the CDU performance and the like of the radiation sensitive resin composition can be further improved.

<[D] Polymer>
[D] The polymer contains a fluorine atom, a silicon atom, or both, and is the sum of the mass content of fluorine atoms and the mass content of silicon atoms (hereinafter also referred to as “total mass content of fluorine atoms and silicon atoms”). ) Is a polymer larger than the total mass content of fluorine atoms and silicon atoms in the polymer [A].

The polymer having higher hydrophobicity than the polymer serving as the base polymer tends to be unevenly distributed in the resist film surface layer, and the [D] polymer has a total mass content of fluorine atoms and silicon atoms as compared to the [A] polymer. Therefore, there is a tendency to be unevenly distributed in the surface layer of the resist film due to the characteristics resulting from the hydrophobicity. As a result, according to the radiation sensitive resin composition, it is possible to suppress the elution of the acid generator, the acid diffusion control agent, and the like during the immersion exposure into the immersion medium. In addition, according to the radiation sensitive resin composition, the advancing contact angle between the resist film and the immersion medium can be controlled within a desired range due to the properties resulting from the hydrophobicity of the [D] polymer, and bubble defects can be controlled. Generation can be suppressed. Furthermore, according to the radiation-sensitive resin composition, the receding contact angle between the resist film and the immersion medium is increased, and high-speed scanning exposure is possible without leaving water droplets. The radiation-sensitive resin composition can form a resist film suitable for the immersion exposure method by containing the [D] polymer as described above. Moreover, the said radiation sensitive resin composition can form the resist pattern by which generation | occurrence | production of the defect was suppressed by containing a [D] polymer.

[D] The lower limit of the total mass content of fluorine atoms and silicon atoms in the polymer is preferably 1% by mass, more preferably 2% by mass, and even more preferably 3% by mass. As an upper limit of the said mass content rate, 60 mass% is preferable, 50 mass% is more preferable, and 40 mass% is further more preferable. By setting the total mass content of fluorine atoms and silicon atoms in the above range, uneven distribution of the [D] polymer in the resist film can be more appropriately adjusted. The total mass content of fluorine atoms and silicon atoms in the polymer can be calculated from the structure of the polymer obtained by ¹³ C-NMR spectrum measurement.

[D] When the polymer is a polymer containing a fluorine atom, the content of the fluorine atom in the [D] polymer is not particularly limited, and may be bonded to any of the main chain, side chain, and terminal. It preferably has a structural unit containing an atom (hereinafter also referred to as “structural unit (F)”).

[Structural unit (F)]
Examples of the structural unit (F) include the following formula (f-1).

In the above formula (f-1), R ^J represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. G is a single bond, an oxygen atom, a sulfur atom, —COO—, —SO ₂ NH—, —CONH— or —OCONH—. R ^K is a monovalent monovalent fluorine cycloaliphatic hydrocarbon group chain fluorinated hydrocarbon group or a C 4-20 having 1 to 6 carbon atoms.

R ^J is preferably a hydrogen atom or a methyl group, and more preferably a methyl group, from the viewpoint of the copolymerizability of the monomer that provides the structural unit (f-1).

G is preferably —COO—, —SO ₂ NH—, —CONH— or —OCONH—, more preferably —COO—.

Said R as the monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms represented by ^K, for example, some or all of the linear hydrogen atoms to 1 carbon atoms which is substituted by fluorine atom 6 Or a branched alkyl group etc. are mentioned.

Carbon atoms represented by R ^K 4 Examples of the monovalent fluorine cycloaliphatic hydrocarbon radical of 1-20, monocyclic some or carbon number of 4 to 20 substitution all of the hydrogen atoms by fluorine atoms or A polycyclic hydrocarbon group is mentioned.

The R ^K, preferably a fluorinated chain hydrocarbon group, a 2,2,2-trifluoroethyl group or a 1,1,1,3,3,3-hexafluoro-2-propyl group is more preferred, 2 More preferred is a 2,2-trifluoroethyl group.

[D] When a polymer has a structural unit (F), as a minimum of the content rate of a structural unit (F), 10 mol% is preferable with respect to all the structural units which comprise a [D] polymer, 20 Mole% is more preferable. As an upper limit of the said content rate, 100 mol% is preferable and 90 mol% is more preferable. By making the content rate of a structural unit (F) into the said range, the mass content rate of the fluorine atom of a [D] polymer can be adjusted further appropriately.

[D] As the polymer, those having an alicyclic structure are preferable. Examples of the structural unit (A) containing an alicyclic structure include a structural unit (A1) containing a non-acid dissociable alicyclic hydrocarbon group. As the structural unit (A1) containing a non-acid-dissociable alicyclic hydrocarbon group, for example, a structural unit containing a non-acid-dissociable hydrocarbon group exemplified as the structural unit (V) of the above-mentioned [A] polymer Among them, those in which the hydrocarbon group is a secondary alicyclic hydrocarbon group or an adamantan-1-yl group are exemplified. [D] When the polymer has a structural unit (A), the lower limit of the content ratio of the structural unit (A) is preferably 10 mol% with respect to all the structural units constituting the polymer. Mole% is more preferable, and 50 mol% is more preferable. As an upper limit of the said content rate, 90 mol% is preferable and 80 mol% is more preferable.

[D] The polymer may have a structural unit (B) containing an acid dissociable group. Examples of the structural unit (B) include the structural unit (I) in the [A] polymer. [D] When a polymer has a structural unit (B), as an upper limit of the content rate of a structural unit (B), 80 mol% is preferable with respect to all the structural units which comprise a [D] polymer, 20 Mole% is more preferable, and 16 mol% is more preferable. As said content rate, more than 0 mol% is preferable, 5 mol% is more preferable, and 10 mol% is further more preferable. Moreover, it is preferable that the [D] polymer does not have a structural unit (B).

[D] The polymer may have a structural unit (C) containing a non-acid-dissociable chain hydrocarbon group. As the structural unit (C) containing a non-acid-dissociable chain hydrocarbon group, for example, the structural unit containing a non-acid-dissociable hydrocarbon group exemplified as the structural unit (V) of the above-mentioned [A] polymer. Among them, the hydrocarbon group is a methyl group, a primary or secondary chain hydrocarbon group, and the like. Examples of the primary chain hydrocarbon group include alkyl groups such as n-butyl group and n-dodecyl group. [D] When the polymer has a structural unit (C), the lower limit of the content ratio of the structural unit (C) is preferably 10 mol% with respect to all the structural units constituting the [D] polymer. Mole% is more preferable. As an upper limit of the said content rate, 50 mol% is preferable and 40 mol% is more preferable.

When the said radiation sensitive resin composition contains a [D] polymer, as a minimum of content of a [D] polymer, 0.1 mass part is preferable with respect to 100 mass parts of [A] polymers. 0.5 parts by mass is more preferable, 1 part by mass is further preferable, and 2 parts by mass is particularly preferable. As an upper limit of the said content, 30 mass parts is preferable, 20 mass parts is more preferable, 15 mass parts is further more preferable, and 10 mass parts is especially preferable. The radiation sensitive resin composition may contain one or more [D] polymers.

[D] The polymer can be synthesized by the same method as the above-mentioned [A] polymer.

[D] The lower limit of Mw of the polymer is preferably 1,000, more preferably 3,000, and still more preferably 4,000. The upper limit of Mw is preferably 50,000, more preferably 20,000, and still more preferably 8,000.

[D] The upper limit of the ratio of Mw to Mn (Mw / Mn) by GPC of the polymer [D] is preferably 5, more preferably 3, still more preferably 2, and particularly preferably 1.5. The lower limit of the ratio is usually 1 and preferably 1.2.

<[E] solvent>
The radiation-sensitive resin composition usually contains an [E] solvent. [E] The solvent is a solvent that can dissolve or disperse at least the [A] polymer, the [B] compound and the [C] compound, and the [D] polymer, [F] nitrogen-containing compound, etc. contained as necessary. If it is, it will not specifically limit.

[E] Examples of the solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like.

Examples of alcohol solvents include aliphatic monoalcohol solvents having 1 to 18 carbon atoms such as 4-methyl-2-pentanol and n-hexanol;
An alicyclic monoalcohol solvent having 3 to 18 carbon atoms such as cyclohexanol;
A polyhydric alcohol solvent having 2 to 18 carbon atoms such as propylene glycol;
Examples thereof include polyhydric alcohol partial ether solvents having 3 to 19 carbon atoms such as propylene glycol monomethyl ether.

Examples of ether solvents include dialkyl ether solvents having 4 to 14 carbon atoms such as diethyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
And aromatic ring-containing ether solvents such as diphenyl ether and anisole.

Examples of the ketone solvents include chain ketone solvents having 3 to 12 carbon atoms such as acetone, methyl ethyl ketone, methyl-iso-butyl ketone, 2-heptanone:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone:
Examples include 2,4-pentanedione, acetonylacetone, acetophenone, and the like.

Examples of the amide solvent include cyclic amide solvents such as N, N′-dimethylimidazolidinone and N-methylpyrrolidone;
Examples thereof include chain amide solvents such as N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, and N-methylpropionamide.

Examples of the ester solvent include monocarboxylic acid ester solvents such as acetate ester solvents such as n-butyl acetate and amyl acetate, and propionate solvents such as ethyl propionate;
Hydroxycarboxylic acid ester solvents such as ethyl lactate and n-butyl glycolate;
Polyhydric alcohol carboxylate solvents such as propylene glycol acetate;
Polyhydric alcohol partial ether carboxylate solvents such as propylene glycol monomethyl ether acetate;
Polycarboxylic acid diester solvents such as diethyl oxalate;
Lactone solvents such as γ-butyrolactone and δ-valerolactone;
Examples thereof include carbonate solvents such as dimethyl carbonate, diethyl carbonate, ethylene carbonate, and propylene carbonate.

Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents having 5 to 12 carbon atoms such as n-pentane and n-hexane;
Examples thereof include aromatic hydrocarbon solvents having 6 to 16 carbon atoms such as toluene and xylene.

[E] The solvent is preferably an ester solvent and / or a ketone solvent, more preferably a polyhydric alcohol partial ether carboxylate solvent, a lactone solvent, a hydroxycarboxylic acid ester and / or a cyclic ketone solvent. The radiation-sensitive resin composition may contain one or more [E] solvents.

<Other optional components>
The radiation-sensitive resin composition may contain, for example, a surfactant, an alicyclic skeleton-containing compound, a sensitizer, and the like as other optional components.

<Method for preparing radiation-sensitive resin composition>
In the radiation sensitive resin composition, for example, the [A] polymer, the [B] compound, the [C] compound, and optional components contained as necessary are mixed in a predetermined ratio, and preferably the obtained mixture The liquid can be prepared, for example, by filtering with a filter having a pore diameter of about 0.2 μm. As a minimum of solid content concentration of the radiation sensitive resin composition, 0.1 mass% is preferred, 0.5 mass part is more preferred, and 1 mass% is still more preferred. As an upper limit of the said solid content concentration, 50 mass% is preferable, 30 mass% is more preferable, and 20 mass% is further more preferable.

<Resist pattern formation method>
The resist pattern forming method includes a step of applying the radiation-sensitive resin composition to at least one surface side of a substrate (hereinafter, also referred to as “coating step”), and a resist film formed by the coating step. And a step of developing the exposed resist film (hereinafter also referred to as “developing step”).

According to the resist pattern forming method, since the radiation-sensitive resin composition described above is used, it is possible to form a resist pattern with a wide depth of focus, a small CDU and LWR, and a high resolution.

[Coating process]
In this step, the radiation sensitive resin composition is applied to at least one surface side of the substrate. Examples of the substrate on which the resist film is formed include a silicon wafer and a wafer coated with aluminum. A resist film is formed by applying the radiation sensitive resin composition on the substrate. Although it does not specifically limit as a coating method of the said radiation sensitive resin composition, For example, well-known methods, such as a spin coat method, etc. are mentioned. When the radiation sensitive resin composition is applied, the amount of the radiation sensitive resin composition to be applied is adjusted so that the resist film to be formed has a desired thickness. In addition, after coating the said radiation sensitive resin composition on a board | substrate, in order to volatilize a solvent, you may pre-bake (henceforth "PAB"). As a minimum of the temperature of PAB, 30 ° C is preferred and 50 ° C is more preferred. As an upper limit of the said temperature, 200 degreeC is preferable and 150 degreeC is more preferable. The lower limit of the PAB time is preferably 10 seconds, and more preferably 30 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds. As a minimum of the average thickness of a resist film, 10 nm is preferred, 20 nm is more preferred, and 50 nm is still more preferred. The upper limit of the average thickness is preferably 1,000 nm, more preferably 200 nm, and even more preferably 150 nm.

[Exposure process]
In this step, the resist film formed by the coating step is exposed. In some cases, this exposure is performed by irradiating with radiation through a mask having a predetermined pattern through an immersion exposure liquid such as water.

As the immersion exposure liquid, a liquid having a refractive index larger than that of air is usually used. Specific examples include pure water, long-chain or cyclic aliphatic compounds, and the like. In this state through the immersion exposure liquid, that is, in a state where the immersion exposure liquid is filled between the lens and the resist film, the exposure apparatus irradiates radiation, and the resist film is formed through a mask having a predetermined pattern. Exposure.

Examples of the radiation include far ultraviolet rays such as visible light, ultraviolet rays, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), and extreme ultraviolet rays (depending on the type of radiation-sensitive acid generator used). Extreme Ultraviolet (EUV), 13.5 nm), electromagnetic waves such as X-rays, electron beams (Electron Beam (EB)), charged particle beams such as α-rays, etc. are used as appropriate. Among these, ArF Excimer laser light, KrF excimer laser light, EUV, X-ray or EB is preferable, and ArF excimer laser light, EUV or EB is more preferable. In addition, exposure conditions, such as exposure amount, can be suitably selected according to the compounding composition of the said radiation sensitive resin composition, the kind of additive, etc.

It is preferable to perform a heat treatment (hereinafter also referred to as “post-exposure baking (post-exposure baking, PEB)”) on the resist film after exposure. By this PEB, the dissociation reaction of an acid dissociable group such as the [A] polymer can be smoothly advanced. The heating conditions for PEB are appropriately adjusted depending on the composition of the radiation sensitive resin composition, but the lower limit of the temperature of PEB is preferably 30 ° C, more preferably 50 ° C, and even more preferably 70 ° C. As an upper limit of the said temperature, 200 degreeC is preferable, 150 degreeC is more preferable, and 120 degreeC is further more preferable. The lower limit of the PEB time is preferably 10 seconds, more preferably 30 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds.

Further, in order to maximize the potential of the radiation-sensitive resin composition, as disclosed in, for example, Japanese Patent Publication No. 6-12452 and Japanese Patent Application Laid-Open No. 59-93448, on the substrate to be used. An organic or inorganic antireflection film can also be formed. Further, in order to prevent the influence of basic impurities contained in the environmental atmosphere, a protective film can be provided on the resist film as disclosed in, for example, JP-A-5-188598.

[Development process]
In this step, the resist film exposed in the exposure step is developed. Examples of the developer used for the development include an aqueous alkali solution (alkaline developer) and a solution containing an organic solvent (organic solvent developer). Thereby, a predetermined resist pattern is formed.

Examples of the alkali developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, Ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3. 0] -5-nonene, and an alkaline aqueous solution in which at least one alkaline compound is dissolved. In these, a TMAH aqueous solution is preferable and a 2.38 mass% TMAH aqueous solution is more preferable.

Examples of the organic solvent developer include organic solvents such as hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, alcohol solvents, and liquids containing organic solvents. Examples of the organic solvent include one or more of the solvents exemplified as the [E] solvent of the above-described radiation-sensitive resin composition. Among these, ester solvents and ketone solvents are preferable. As the ester solvent, an acetate solvent is preferable, and amyl acetate and n-butyl acetate are more preferable. The ketone solvent is preferably a chain ketone, more preferably 2-heptanone. The lower limit of the content of the organic solvent in the organic solvent developer is preferably 80% by mass, more preferably 90% by mass, further preferably 95% by mass, and particularly preferably 99% by mass. Examples of components other than the organic solvent in the organic solvent developer include water and silicone oil.

These developers may be used alone or in combination of two or more. In general, after development, the substrate is washed with water or an alcohol solvent and dried.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. The measuring method of various physical property values is shown below.

[Measurement of weight average molecular weight (Mw), number average molecular weight (Mn) and dispersity (Mw / Mn)]
Using Tosoh's GPC columns ("G2000HXL", "G3000HXL", "G4000HXL"), flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column temperature: 40 ° C, It was measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard.

[ ¹ H-NMR analysis and ¹³ C-NMR analysis]
Measurement was performed using “JNM-Delta400” manufactured by JEOL.

<Synthesis of polymer>
The monomers used in the synthesis of each polymer in each example and comparative example are shown below. In the following synthesis examples, unless otherwise specified, parts by mass means a value when the total mass of the monomers used is 100 parts by mass, and mol% indicates the total number of moles of the monomers used. It means the value when it is 100 mol%.

[[A] Synthesis of polymer]
[Synthesis Example 1] (Synthesis of polymer (A-1))
Compound (M-2), compound (M-3), compound (M-6) and compound (M-7) as monomers are mixed with 2-butanone so that the molar ratio is 25/20/45/10. Dissolved in (200 parts by mass). Azobisisobutyronitrile (AIBN) (2 mol% based on the total monomers) was added as an initiator to prepare a monomer solution. 2-Butanone (100 parts by mass) was placed in the reaction vessel and purged with nitrogen for 30 minutes. The monomer solution was added dropwise over 3 hours while stirring in a reaction vessel at 80 ° C. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was cooled with water and cooled to 30 ° C. or lower. The cooled polymerization solution was put into methanol (2,000 parts by mass), and the precipitated white powder was filtered off. The filtered white powder was washed twice with methanol (400 parts by mass), filtered, and dried at 50 ° C. for 17 hours to obtain a white powdery polymer (A-1) in good yield. .

[Synthesis Example 2] (Synthesis of Polymer (A-2))
Polymers (A-2) were synthesized by using the types and amounts of monomers shown in Table 1 below, appropriately selecting the amount of initiator, and performing the same operations as in Synthesis Example 1.

[Synthesis Example 3] (Synthesis of Polymer (A-3))
The compound (M-1) and the compound (M-10) as monomers were dissolved in propylene glycol monomethyl ether (100 parts by mass) so that the molar ratio was 43/57. A monomer solution was prepared by adding AIBN (6 mol% based on the total monomers) as an initiator and t-dodecyl mercaptan (38 parts by mass with respect to 100 parts by mass of the initiator) as a chain transfer agent. did. This monomer solution was copolymerized under a nitrogen atmosphere while maintaining the reaction temperature at 70 ° C. for 16 hours. After completion of the polymerization reaction, the polymerization solution was dropped into n-hexane (1,000 parts by mass) to solidify and purify the polymer. To the polymer, propylene glycol monomethyl ether (150 parts by mass) was added again. Further, methanol (150 parts by mass), triethylamine (1.5 molar equivalents relative to the amount of compound (M-10) used) and water (1.5 molar equivalents relative to the amount of compound (M-10) used) were added. Then, the hydrolysis reaction was carried out for 8 hours while refluxing at the boiling point. After completion of the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the resulting polymer was dissolved in acetone (150 parts by mass). This was dropped into water (2,000 parts by mass) to solidify, and the produced white powder was filtered off. It was dried at 50 ° C. for 17 hours to obtain a white powdery polymer (A-3) in good yield.

Table 1 below shows the content of each structural unit of the polymers (A-1) to (A-3), Mw, and Mw / Mn. “M-10 *” in Table 1 indicates that the content ratio of the structural unit is a value for a hydroxystyrene unit derived from (M-10).

[[D] Synthesis of polymer]
[Synthesis Example 4] (Synthesis of Polymer (D-1))
Compound (M-4) and compound (M-9) as monomers were dissolved in 2-butanone (200 parts by mass) so that the molar ratio was 70/30. AIBN (5 mol% with respect to all monomers) was added here as an initiator to prepare a monomer solution. 2-Butanone (100 parts by mass) was placed in the reaction vessel and purged with nitrogen for 30 minutes. The inside of the reaction vessel was set to 80 ° C., and the monomer solution was added dropwise over 3 hours with stirring. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was cooled with water and cooled to 30 ° C. or lower. After replacing the solvent with acetonitrile (400 parts by mass), the operation of adding hexane (100 parts by mass) and stirring to recover the acetonitrile layer was repeated three times. By replacing the solvent with propylene glycol monomethyl ether acetate, a solution of the polymer (D-1) was obtained in good yield.

[Synthesis Examples 5 to 7] (Synthesis of polymers (D-2) to (D-4))
Polymers (D-2) to (D-4) were synthesized in the same manner as in Synthesis Example 4 except that the types and amounts of monomers shown in Table 2 were used.

Table 2 below also shows the content ratio, Mw and Mw / Mn of each structural unit of the polymers (D-1) to (D-4).

<Synthesis of [B] Compound>
[Synthesis Example 8] (Synthesis of Compound (B-2))
With reference to Example 18 of JP2014-224984, compound (B-2) was synthesized by using tris (4-methylphenyl) sulfonium chloride instead of triphenylsulfonium chloride.

[Synthesis Example 9] (Synthesis of Compound (B-5))
Compound (B-5) was synthesized with reference to Synthesis Example 10 of Japanese Patent Application No. 2016-125021.

<Preparation of radiation-sensitive resin composition>
[B] compound, [C] compound, and [E] solvent which comprise a radiation sensitive resin composition are shown below.

[[B] Compound]
B-1 to B-6: Compounds represented by the following formulas (B-1) to (B-6)

[[C] Compound]
C-1 to C-7: Compounds represented by the following formulas (C-1) to (C-7)

[[E] solvent]
E-1: Propylene glycol monomethyl ether acetate E-2: Cyclohexanone E-3: γ-butyrolactone E-4: Ethyl lactate

[Preparation of radiation-sensitive resin composition for ArF exposure]
[Example 1]
[A] 100 parts by mass of (A-1) as a polymer, 14.0 parts by mass of (B-1) as a [B] compound, 2.3 parts by mass of (C-2) as a [C] compound, [D] 7 parts by mass of (D-1) as a polymer, and (E-1) 2,240 parts by mass, (E-2) 960 parts by mass and (E-3) 30 parts by mass as a solvent [E] The parts were mixed and filtered through a membrane filter having a pore size of 0.2 μm to prepare a radiation sensitive resin composition (J-1).

[Examples 2 to 15 and Comparative Examples 1 to 6]
The radiation-sensitive resin compositions (J-2) to (J-15) and (CJ-1) to (CJ-1) to (C CJ-6) was prepared.

<Formation of resist pattern (1)> (ArF exposure, organic solvent development)
After applying a composition for forming a lower antireflection film (“ARC66” from Brewer Science) using a spin coater (“CLEAN TRACK ACT12” from Tokyo Electron) on the surface of a 12-inch silicon wafer, 205 By heating at 60 ° C. for 60 seconds, a lower antireflection film having an average thickness of 105 nm was formed. Each radiation sensitive resin composition was coated on the lower antireflection film using the spin coater, and PAB was performed at 120 ° C. for 50 seconds. Thereafter, the mixture was cooled at 23 ° C. for 30 seconds to form a resist film having an average thickness of 90 nm. Next, this resist film was subjected to an optical condition of NA = 1.35, Annular (σ = 0.8 / 0.6) using an ArF excimer laser immersion exposure apparatus (“TWINSCAN XT-1900i” manufactured by ASML). Then, exposure was performed through a mask pattern for forming a resist pattern having a space of 44 nm and a pitch of 102 nm. After the exposure, PEB was performed at 90 ° C. for 50 seconds. Thereafter, paddle development was performed for 10 seconds at 23 ° C. using n-butyl acetate, and spin drying was performed by shaking off at 2,000 rpm for 15 seconds to form a resist pattern having a 45 nm space. When this resist pattern was formed, the exposure amount for forming a pattern having a width of 45 nm was determined as the optimum exposure amount (Eop1).

<Evaluation>
Each of the radiation sensitive resin compositions was evaluated by measuring the formed resist pattern according to the following method. A scanning electron microscope (Hitachi High-Technologies “CG-5000”) was used for measuring the resist pattern.

[CDU performance]
The resist pattern was formed by adjusting the mask size so as to form a 45 nm hole, 110 nm pitch pattern by irradiating the exposure amount of Eop1 obtained above. The formed resist pattern was observed from above the pattern using the scanning electron microscope. The hole diameter is measured at 16 points in the range of 500 nm and the average value is obtained. The average value is measured at a total of 500 points, and the 3 sigma value is obtained from the distribution of the measured values. ). The smaller the value of the CDU performance, the better the variation in hole diameter over a long period. The CDU performance can be evaluated as “good” when it is 6.0 nm or less, and “bad” when it exceeds 6.0 nm.

[Depth of focus (DOF performance)]
The resist pattern was formed by adjusting the mask size so as to form a 45 nm hole, 800 nm pitch pattern by irradiating the exposure amount of Eop1 obtained above. About the formed resist pattern, the dimension at the time of changing a focus to a depth direction was observed from the pattern upper part using the said scanning electron microscope. At this time, the margin (nm) in the depth direction in which the pattern dimensions were within 90% to 110% of the reference without any bridge or residue was measured, and the measured margin was defined as the depth of focus (nm). The larger the value of the depth of focus, the better the process margin. The DOF performance can be evaluated as “good” when it is 40 nm or more, and “bad” when it is below 40 nm.

[LWR performance]
The resist pattern was formed by adjusting the mask size so as to form a pattern of 45 nm space and 800 nm pitch by irradiating the exposure amount of Eop1 obtained above. The formed resist pattern was observed from above the pattern using the scanning electron microscope. Measure the total line width variation at 500 points, find the 3 sigma value from the measured value distribution, measure the hole diameter at 16 points in the 500 nm range, find the mean value, and calculate the mean value at any point. 500 points were measured, a 3 sigma value was determined from the distribution of the measured values, and this was defined as LWR performance (nm). The smaller the value of the LWR performance, the smaller the line play and the better. The LWR performance can be evaluated as “good” when it is 5.8 nm or less and “bad” when it exceeds 5.8 nm.

The evaluation results of the above CDU performance, depth of focus and LWR performance are shown below.

As is clear from the results in Table 4 above, the radiation-sensitive resin compositions of the examples had good CDU performance, LWR performance, and depth of focus.

[Preparation of radiation-sensitive resin composition for electron beam exposure]
[Example 16]
[A] 100 parts by mass of (A-3) as a polymer, 14.0 parts by mass of (B-1) as a [B] compound, 2.3 parts by mass of (C-2) as a [C] compound, In addition, (E-1) 4,280 parts by mass and (E-4) 1,830 parts by mass as [E] solvent are mixed and filtered through a membrane filter having a pore size of 0.2 μm to obtain a radiation-sensitive resin composition. A product (J-16) was prepared.

[Examples 17 and 18 and Comparative Example 7]
Radiation-sensitive resin compositions (J-17), (J-18), and (CJ-7) were prepared in the same manner as in Example 16 except that the components having the types and contents shown in Table 5 were used. did.

<Formation of resist pattern (2)> (electron beam exposure, alkali development)
Using a spin coater (“CLEAN TRACK ACT8” manufactured by Tokyo Electron Ltd.) on the surface of an 8-inch silicon wafer, each radiation sensitive resin composition was applied, and PAB was performed at 90 ° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with an average thickness of 50 nm. Next, the resist film was irradiated with an electron beam by using a simple electron beam drawing apparatus (“HL800D” manufactured by Hitachi, Ltd., output: 50 KeV, current density: 5.0 A / cm ² ). After irradiation, PEB was performed at 120 ° C. for 60 seconds. Thereafter, development was performed at 23 ° C. for 30 seconds using a 2.38 mass% TMAH aqueous solution as an alkali developer, washed with water, and dried to form a resist pattern having 90 nm holes and 180 nm pitches. The exposure amount for forming this 90 nm hole 180 nm pitch resist pattern was determined as the optimum exposure amount (Eop2).

<Evaluation>
About the radiation sensitive resin composition, according to the following method, CDU performance and resolution lithography performance were evaluated. A scanning electron microscope (Hitachi High-Technology “S-9380”) was used for measuring the resist pattern.

[CDU performance]
The CDU performance was measured in the same manner as described in the above resist pattern formation (1). The smaller the value of the CDU performance, the better the variation in hole diameter over a long period. The CDU performance can be evaluated as “good” when it is 1.1 nm or less and “bad” when it exceeds 1.1 nm.

[Resolution]
The resist pattern formed by irradiating the exposure amount of Eop2 obtained above was observed from above the pattern using the scanning electron microscope. When the mask size was reduced in steps of 1 nm, the minimum hole diameter formed was defined as resolution (nm). The smaller the value is, the better the resolution limit is and the fine pattern can be formed. The resolution can be evaluated as “good” when it is 70 nm or less, and “bad” when it exceeds 70 nm.

The evaluation results of the CDU performance and resolution are shown in Table 6 below.

As is clear from the results in Table 6, the radiation-sensitive resin compositions of the examples all had good CDU performance and resolution. In this example, an electron beam was used for the exposure of the resist film, but it is known that the basic resist characteristics are similar even when short wavelength radiation such as EUV is used. It is also known that there is a correlation. Therefore, according to the radiation-sensitive resin composition of this example, it is presumed that the CDU performance and the resolution are excellent even in the case of EUV exposure.

[Preparation of radiation-sensitive resin composition for EUV exposure]
[Examples 19 to 21 and Comparative Examples 8 and 9]
The radiation-sensitive resin compositions (J-19) to (J-21) and (CJ-8) and (CJ-8) were used in the same manner as in Example 16 except that the components having the types and contents shown in Table 7 were used. CJ-9) was prepared.

<Formation of resist pattern (3)> (EUV exposure, alkali development)
A silicon-containing spin-on hard mask “SHB-A940” (with a silicon content of 43 mass%) was spin-coated on a Si substrate having an average thickness of 20 nm and a hot plate was used at 105 ° C. PAB was performed for 60 seconds to form a resist film having an average thickness of 60 nm. This is exposed using an EUV scanner (“NXE3300” manufactured by ASML (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, hole pattern mask with a pitch on the wafer of 46 nm and + 20% bias)). Then, PEB was performed on a hot plate at 120 ° C. for 60 seconds, and development was performed with a 2.38 mass% TMAH aqueous solution for 30 seconds to form a resist pattern having 23 nm holes and 46 nm pitches. The exposure amount for forming the resist pattern having the 23 nm holes and 46 nm pitch was set as the optimum exposure amount (Eop3).

<Evaluation>
About the radiation sensitive resin composition, according to the following method, CDU performance and resolution lithography performance were evaluated. For measuring the resist pattern, a scanning electron microscope (“CG-5000” manufactured by Hitachi High-Technologies Corporation) was used.

[CDU performance]
The CDU performance was measured in the same manner as described in the above resist pattern formation (1). The smaller the value of the CDU performance, the better the variation in hole diameter over a long period. The CDU performance can be evaluated as “good” when it is 3.5 nm or less and “bad” when it exceeds 3.5 nm.

[Resolution]
The resolution was measured in the same manner as described in the above resist pattern formation (2). The smaller the value is, the better the resolution limit is and the fine pattern can be formed. The resolution can be evaluated as “good” when it is 20 nm or less, and “bad” when it exceeds 20 nm.

The evaluation results of the CDU performance and resolution are shown in Table 8 below.

As is clear from the results in Table 8, the radiation-sensitive resin compositions of the examples all had good CDU performance and resolution in EUV exposure.

Claims

A first polymer having a structural unit containing an acid dissociable group;
A first compound that generates a first acid that dissociates the acid dissociable group at 110 ° C. for 1 minute by irradiation with radiation;
Containing a second compound that generates a second acid that is not substantially dissociated at 110 ° C. for 1 minute under the conditions of 110 ° C.
The content of the first compound is 10% by mass or more in the total solid content (all components other than the solvent in the composition),
Moles of B m of the first compound, the number of moles of the second compound when the C m, B m / C m is the radiation-sensitive resin composition is 1.7 or more.
The radiation-sensitive resin composition according to claim 1, wherein the first compound is a salt of a radiation-sensitive cation and an anion obtained by removing a proton from the acid group of the first acid.
The radiation-sensitive resin composition according to claim 1 or 2, wherein the second compound is a salt of a radiation-sensitive cation and an anion obtained by removing a proton from the acid group of the second acid.
A second polymer containing a fluorine atom or a silicon atom or both, wherein the sum of the mass content of fluorine atoms and the mass content of silicon atoms in the second polymer is fluorine in the first polymer; The radiation sensitive resin composition of Claim 1, Claim 2 or Claim 3, which is larger than the sum of the mass content of atoms and the mass content of silicon atoms.
The radiation sensitive resin composition according to claim 4, wherein the second polymer has an alicyclic structure.
The radiation sensitive resin according to claim 4 or 5, wherein the second polymer has a structural unit containing an acid dissociable group, and the content ratio of the structural unit is more than 0 mol% and 20 mol% or less. Composition.
The radiation sensitive resin composition according to claim 4 or 5, wherein the second polymer does not have a structural unit containing an acid dissociable group.
The radiation-sensitive material according to any one of claims 1 to 7, wherein the second acid is a carboxylic acid, a sulfonamidic acid, a sulfonic acid not containing a fluorine atom (excluding a sulfomalonic acid ester), or a combination thereof. Resin composition.
The radiation sensitive resin according to any one of claims 1 to 8, wherein the first acid is a sulfomalonic acid ester, a sulfonic acid containing a fluorine atom, a disulfonylimide acid containing a fluorine atom, or a combination thereof. Composition.
The radiation-sensitive resin composition according to claim 8 or 9, which is for ArF exposure.
The said Bm / Cm is 2.6 or more, The radiation sensitive resin composition of Claim 1, Claim 2, or Claim 3.
The radiation-sensitive resin composition according to claim 11, wherein the second acid is carboxylic acid, sulfonamidic acid or a combination thereof.
The radiation-sensitive resin composition according to claim 11 or 12, wherein the first acid is sulfonic acid, disulfonylimide acid, or a combination thereof.
The radiation-sensitive resin composition according to claim 12 or 13, which is for extreme ultraviolet (EUV) or electron beam (EB) exposure.
The radiation sensitive resin composition according to any one of claims 1 to 14, wherein the second compound does not contain a nitrogen atom.
The radiation-sensitive resin composition according to any one of claims 1 to 15, which is used for organic solvent development.
Applying the radiation sensitive resin composition according to any one of claims 1 to 16 to at least one surface side of the substrate;
Exposing the resist film formed by the coating process;
And a step of developing the exposed resist film.
The resist pattern forming method according to claim 17, wherein the developing step is performed with a developer containing an organic solvent.