TW202413457A - Photosensitive radiation or radiation-sensitive resin composition, photoresist film, pattern forming method, and manufacturing method of electronic device - Google Patents

Abstract

A photosensitive or radiation-sensitive resin composition, a photoresist film, a pattern forming method, and a method for manufacturing an electronic device including the above-mentioned pattern forming method, wherein the photosensitive or radiation-sensitive resin composition contains a resin (A), and the resin (A) contains a repeating unit represented by formula (a1) and at least one repeating unit selected from the group consisting of a repeating unit represented by formula (a2) and a repeating unit represented by formula (a3). ^X1 represents a halogen atom, ^W1 represents an aromatic group, and ^R1 represents a hydrogen atom or a substituent. ^R1 may bond with ^W1 to form a ring. ^X2 represents an alkyl group, ^W2 represents an aromatic group, and ^R2 represents a hydrogen atom or a substituent. ^R2 may bond with ^X2 or ^W2 to form a ring. ^X3 represents a halogen atom, a cyano group, ^-COORA1 , ^-OCORA2 , _-SO2RA3 or an alkyl group. ^RA1 , ^RA2 and ^RA3 each independently represent an organic group. ^R3 represents a hydrogen atom or a substituent, ^L1 represents a linking group, ^{and W3} represents an organic group. ^R3 may bond with ^X3 or ^R3 to form a ring.

Description

Photosensitive or radiation-sensitive resin composition, photoresist film, pattern forming method, and method for manufacturing electronic device

The present invention relates to a photosensitive or radiation-sensitive resin composition, a photoresist film, a pattern forming method, and a method for manufacturing an electronic device.

Since the development of photoresists for KrF excimer lasers (248nm), a pattern formation method using chemical amplification has been adopted to compensate for the decrease in sensitivity caused by light absorption. For example, in the positive chemical amplification method, first, the photoacid generator contained in the exposure part is decomposed by light irradiation to generate acid. Then, in the post-exposure baking (PEB: Post Exposure Bake) process, the alkali-insoluble groups of the resin contained in the photosensitive or radiation-sensitive resin composition are changed to alkali-soluble groups by the catalytic action of the generated acid, thereby changing the solubility in the developer. After that, development is performed using, for example, an alkaline aqueous solution. In this way, the exposure part is removed to obtain the desired pattern. In order to miniaturize semiconductor devices, the exposure light source has been shortened to a shorter wavelength and the projection lens has been made to have a higher numerical aperture (high NA). Currently, an exposure machine using an ArF excimer laser with a wavelength of 193nm as a light source has been developed. In addition, recently, a pattern forming method using extreme ultraviolet light (EUV light: Extreme Ultraviolet) and electron beam (EB: Electron Beam) as a light source is being studied. Under such circumstances, various structures have been proposed as photosensitive or radiation-sensitive resin compositions.

For example, Patent Documents 1 and 2 describe polymers whose molecular weight is reduced by severing the main chain through electron beam irradiation. [Prior Art Document] [Patent Document]

Patent document 1: Japanese Patent Publication No. 2017-218480 Patent document 2: Japanese Patent Publication No. 61-126547

[The problem that the invention wants to solve]

The inventors of the present invention prepared and studied an actinic radiation or radiation-sensitive resin composition containing a specified polymer with reference to Patent Document 1, and found that the sensitivity did not meet the level required recently, and there was room for further improvement. In addition, when the pattern formed by the above composition was formed, especially when an ultrafine pattern (for example, a pattern with a line width of 20 nm or less) was formed, the LWR (line width roughness) performance was poor, and there was obviously room for further improvement.

Therefore, the subject of the present invention is to provide a photosensitive or radiation-sensitive resin composition that can form a pattern with excellent sensitivity and excellent LWR performance. In addition, the subject of the present invention is to provide a photoresist film formed using the above-mentioned photosensitive or radiation-sensitive resin composition, a pattern forming method using the above-mentioned photosensitive or radiation-sensitive resin composition, and a method for manufacturing an electronic device. [Means for solving the problem]

The inventors of the present invention have found that the above-mentioned problem can be solved by the following structure.

[1] A photosensitive or radiation-sensitive resin composition, wherein the photosensitive or radiation-sensitive resin composition contains a resin (A), wherein the resin (A) contains a repeating unit represented by the following formula (a1) and at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (a2) and a repeating unit represented by the following formula (a3).

[Chemical formula 1]

In formula (a1), ^X1 represents a halogen atom. ^W1 represents an aromatic group, and ^R1 represents a hydrogen atom or a substituent. ^R1 may bond with ^W1 to form a ring. In formula (a2), ^X2 represents an alkyl group. ^W2 represents an aromatic group, and ^R2 represents a hydrogen atom or a substituent. ^R2 may bond with ^X2 or ^W2 to form a ring. In formula (a3), ^X3 represents a halogen atom, a cyano group, ^-COORA1 , ^-OCORA2 , _-SO2RA3 or an alkyl group. ^RA1 , ^RA2 and ^RA3 each independently represent an organic group. ^R3 represents a hydrogen atom or a substituent. ^L1 represents a linking group ^{. W3} represents an organic group. ^R3 may bond with ^X3 or ^R3 to form a ring. [2] The actinic or radiation-sensitive resin composition as described in [1], further comprising an ionic compound (B), and the resin (A) has an interactive group that interacts with the ionic compound (B). [3] The actinic or radiation-sensitive resin composition as described in [2], wherein the interactive group is a phenolic hydroxyl group or a carboxyl group. [4] The actinic or radiation-sensitive resin composition as described in any one of [1] to [3], wherein ^L1 in the above formula (a3) represents -O-. [5] The actinic or radiation-sensitive resin composition as described in any one of [1] to [4], wherein ^W3 in the above formula (a3) represents an alkyl group, a cycloalkyl group or an aryl group. [6] A photoresist film formed using the photosensitive or radiation-sensitive resin composition as described in any one of [1] to [5]. [7] A pattern forming method comprising: a process of forming a film using the photosensitive or radiation-sensitive resin composition as described in any one of [1] to [5]; a process of exposing the film; and a process of developing the exposed film using a developer. [8] A method for manufacturing an electronic device, comprising the pattern forming method as described in [7]. [Effect of the invention]

According to the present invention, a photosensitive or radiation-sensitive resin composition capable of forming a pattern with excellent sensitivity and excellent LWR performance can be provided. In addition, according to the present invention, a photoresist film formed using the above-mentioned photosensitive or radiation-sensitive resin composition, a pattern forming method using the above-mentioned photosensitive or radiation-sensitive resin composition, and a method for manufacturing an electronic device can be provided.

The present invention is described in detail below. The description of the constituent elements described below is sometimes based on representative embodiments of the present invention, but the present invention is not limited to such embodiments. For the notation of the groups (atomic groups) in this specification, as long as it is not contrary to the main purpose of the present invention, the notation notating substitution and unsubstituted includes both groups without substituents and groups with substituents. For example, "alkyl" includes not only alkyl groups without substituents (unsubstituted alkyl groups) but also alkyl groups with substituents (substituted alkyl groups). In addition, the so-called "organic group" in this specification refers to a group containing at least one carbon atom. Unless otherwise specified, the substituent is preferably a monovalent substituent. The term "actinic ray" or "radiation" in this specification refers to, for example, the bright line spectrum of mercury lamps, far ultraviolet rays represented by excimer lasers, extreme ultraviolet rays (EUV: Extreme Ultraviolet), X-rays, and electron beams (EB: Electron Beam). The term "light" in this specification refers to actinic ray or radiation. Unless otherwise specified, "exposure" in this specification includes not only exposure using the bright line spectrum of mercury lamps, far ultraviolet rays represented by excimer lasers, extreme ultraviolet rays, X-rays, and EUV, but also drawing using particle beams such as electron beams and ion beams. In this specification, "~" is used to include the numerical values before and after it as lower and upper limits. The bonding direction of the divalent groups described in this specification is not limited unless otherwise specified. For example, in the compound represented by the formula "X-Y-Z", when Y is -COO-, Y can be -CO-O- or -O-CO-. In addition, the above compound can be either "X-CO-O-Z" or "X-O-CO-Z".

In this specification, the weight average molecular weight (Mw), number average molecular weight (Mn), and dispersion degree (also called molecular weight distribution) (Mw/Mn) of the resin are defined as polystyrene conversion values obtained by GPC (Gel Permeation Chromatography) measurement using a GPC (HLC-8120GPC manufactured by Tosoh Corporation) apparatus (solvent: tetrahydrofuran, flow rate (sample injection amount): 10 μL, column: TSK gel Multipore HXL-M manufactured by Tosoh Corporation, column temperature: 40°C, flow rate: 1.0 mL/min, detector: Refractive Index Detector).

In this specification, the acid dissociation constant (pKa) refers to the pKa in aqueous solution. Specifically, it is a value calculated based on the values of the Hammett substituent constant and the database of known literature values using the following software package 1. The pKa values described in this specification are all values calculated using the software package.

Package 1: Advanced Chemistry Development (ACD/Labs) Software V8.14 for Solaris (1994-2007 ACD/Labs).

On the other hand, pKa can also be obtained by molecular orbital calculation. As a specific method, a method of calculating the H ⁺ dissociation free energy in an aqueous solution based on a thermodynamic cycle can be cited. Regarding the calculation method of H ⁺ dissociation free energy, for example, it can be calculated by DFT (density functional theory), but there are also various other methods reported in the literature, and the calculation method is not limited to this. In addition, there are a variety of software that can implement DFT, for example, Gaussian16 can be cited.

As mentioned above, the pKa in this specification refers to the value obtained by calculation based on the Hammett substituent constant and the value of the database of known literature values using software package 1. However, when the pKa cannot be calculated using this method, the value obtained using Gaussian16 based on DFT (density functional theory) is adopted. In addition, as mentioned above, the pKa in this specification refers to "pKa in aqueous solution". When the pKa in aqueous solution cannot be calculated, the "pKa in dimethyl sulfoxide (DMSO) solution" is adopted.

In the present specification, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In this specification, the so-called solid component means the component forming the photoresist film, excluding the solvent. Moreover, if it is a component forming the photoresist film, it is also regarded as a solid component even if its property is liquid.

[Acticular radiation-sensitive or radiation-sensitive resin composition] The acticular radiation-sensitive or radiation-sensitive resin composition of the present invention (hereinafter also referred to as "photoresist composition") is an acticular radiation-sensitive or radiation-sensitive resin composition as follows, which contains a resin (A) containing a repeating unit represented by the following formula (a1) and at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (a2) and a repeating unit represented by the following formula (a3).

[Chemical formula 2]

In formula (a1), ^X1 represents a halogen atom. ^W1 represents an aromatic group, and ^R1 represents a hydrogen atom or a substituent. ^R1 may bond with ^W1 to form a ring. In formula (a2), ^X2 represents an alkyl group. ^W2 represents an aromatic group, and ^R2 represents a hydrogen atom or a substituent. ^R2 may bond with ^X2 or ^W2 to form a ring. In formula (a3), ^X3 represents a halogen atom, a cyano group, ^-COORA1 , ^{-OCORA2 , -SO2RA3 or an alkyl group. RA1, RA2 and RA3} _each ^{independently represent an} organic group. ^R3 represents a hydrogen atom or a substituent. ^L1 represents a linking group. ^W3 represents an organic group. ^R3 may bond with ^X3 or ^R3 to form a ring.

The photoresist composition of the present invention can form a pattern with excellent sensitivity and excellent LWR performance by means of the above structure. The reason is not yet completely clear, but the inventors of the present invention speculate as follows. The photoresist composition of the present invention contains a resin (A) containing a repeating unit represented by (a1), which suppresses the side reactions (crosslinking reactions and reverse reactions) accompanying the main chain scission reaction, improves the efficiency of the main chain scission reaction, and thus improves the sensitivity and LWR performance. Hereinafter, the sensitivity of the photoresist composition is more excellent, and/or the LWR performance of the pattern formed by the photoresist composition is more excellent, which is also referred to as "the effect of the present invention is more excellent".

Hereinafter, various components included in the photoresist composition will be described first.

[Resin (A)] ＜Repeating unit represented by (a1)＞ Resin (A) contains the repeating unit represented by the above formula (a1). Resin (A) functions as a so-called main chain cleavage type polymer by containing the repeating unit represented by the above formula (a1). In the main chain cleavage type polymer, the main chain is cut by irradiation with actinic rays or radiation (preferably X-rays, electron beams or extreme ultraviolet rays). Resin (A) may be a homopolymer or a copolymer. When resin (A) is a copolymer, it may be a random copolymer, a block copolymer or an alternating copolymer.

In (a1), ^X1 represents a halogen atom. ^X1 is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. From the viewpoint of better stability of the resin (A), it is more preferably a fluorine atom or a chlorine atom, and further preferably a fluorine atom. The resin (A) may contain only one type of repeating unit represented by (a1), or may contain two or more types. When the resin (A) contains two or more types of repeating units represented by (a1), the halogen atoms (e.g., fluorine atom and chlorine atom, etc.) above ^X1 may also be two or more types.

In (a1), ^W1 represents an aromatic group. The aromatic group represented by ^W1 may be an aromatic alkyl group or an aromatic heterocyclic group. The aromatic alkyl group (aryl group) of ^W1 is preferably an aromatic alkyl group having 6 to 20 carbon atoms, more preferably an aromatic alkyl group having 6 to 15 carbon atoms, further preferably a phenyl group or a naphthyl group, and particularly preferably a phenyl group. The aromatic heterocyclic group (heteroaryl group) of ^W1 preferably contains at least one heteroatom selected from the group consisting of a sulfur atom, a nitrogen atom and an oxygen atom. The number of heteroatoms contained in the aromatic heterocyclic group is preferably 1 to 5, more preferably 1 to 3. The carbon number of the aromatic heterocyclic group is not particularly limited, but is preferably 2 to 20, more preferably 3 to 15. The aromatic heterocyclic group may be monocyclic or polycyclic. Examples of the aromatic heterocyclic group represented by ^W1 include thienyl, furanyl, benzothienyl, dibenzothienyl, benzofuranyl, pyrrole, oxazolyl, thiazolyl, pyridyl, isothiazolyl, thiadiazolyl, and the like. The aromatic group represented by ^W1 may have a substituent. The substituent is not particularly limited, and examples thereof include alkyl (e.g., an alkyl group having 1 to 10 carbon atoms), cycloalkyl (e.g., a cycloalkyl group having 3 to 20 carbon atoms), alkoxy (e.g., a cycloalkyl group having 1 to 10 carbon atoms), hydroxyl, and carboxyl.

In formula (a2), R ¹ represents a hydrogen atom or a substituent. The substituent of R ¹ is not particularly limited, but is preferably an organic group. The organic group is not particularly limited, and for example, the groups exemplified by the organic group W below can be cited.

(Organic group W) Examples of the organic group W include alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aralkyl, cyano, alkoxy, aryloxy, heterocyclic oxy, acyl (e.g., alkylcarbonyl or arylcarbonyl), acyloxy (e.g., alkylcarbonyloxy or arylcarbonyloxy), carbamoyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, alkylthio, arylthio, heterocyclic thio, alkyl or arylsulfinyl, alkyl or arylsulfonyl, aryloxycarbonyl, alkoxycarbonyl, aryl or heterocyclic azo, sulfonamide, imide, amide, carbamoyl, lactone, etc. In addition, if possible, each of the above groups may further have a substituent. For example, as one form of the organic group W, an alkyl group that may have a substituent is also included. The substituent is not particularly limited, and for example, one or more of the groups represented by the organic group W, a halogen atom, a nitro group, a primary to a tertiary amine group, a phosphine group, a phosphinyl group, a phosphinyloxy group, a phosphinylamine group, a phosphonyl group, a silane group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, etc. (hereinafter, these are also referred to as "substituents T"). In addition, the number of carbon atoms possessed by the organic group W is, for example, 1 to 20. In addition, the number of atoms other than hydrogen atoms possessed by the organic group W is, for example, 1 to 30.

In addition, the carbon number of the alkyl group exemplified as the organic group W is preferably 1 to 20, more preferably 1 to 10, and further preferably 1 to 6. The alkyl group may be any of a linear chain and a branched chain. As the alkyl group, for example, a linear chain or branched chain alkyl group such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, and an n-hexyl group may be cited. Among the alkyl groups that may have a substituent, the substituent that the alkyl group may have is not particularly limited, and for example, the groups exemplified by the substituent T mentioned above may be cited.

As the alkyl moiety in the alkoxy group (including the alkoxy moiety in the substituent group containing the alkoxy group (for example, alkoxycarbonyloxy group)), the alkyl moiety in the aralkyl group, the alkyl moiety in the alkylcarbonyl group, the alkyl moiety in the alkylcarbonyloxy group, the alkyl moiety in the alkylthio group, the alkyl moiety in the alkylsulfinyl group, and the alkyl moiety in the alkylsulfonyl group exemplified in the organic group W, the above-mentioned alkyl groups are preferred. In addition, in the alkoxy group which may have a substituent, the aralkyl group which may have a substituent, the alkylcarbonyloxy group which may have a substituent, the alkylthio group which may have a substituent, the alkylsulfinyl group which may have a substituent, and the alkylsulfonyl group which may have a substituent, the same substituent as the substituent in the alkyl group which may have a substituent can be cited.

As the cycloalkyl group exemplified in the organic group W, monocyclic cycloalkyl groups such as cyclopentyl and cyclohexyl, and polycyclic cycloalkyl groups such as norbornyl, tetracyclodecyl, tetracyclododecyl, and adamantyl can be cited. The carbon number of the above cycloalkyl group is preferably 5 to 20, and more preferably 5 to 15. In the cycloalkyl group that may have a substituent, the substituent that the cycloalkyl group may have can be the same as the substituent in the alkyl group that may have a substituent. The alkenyl group exemplified in the organic group W can be either straight chain or branched chain. The carbon number of the above alkenyl group is preferably 2 to 20. In the alkenyl group that may have a substituent, the substituent that the alkenyl group may have can be the same as the substituent in the alkyl group that may have a substituent. The carbon number of the cycloalkenyl group exemplified in the organic group W is preferably 5 to 20. In the cycloalkenyl group which may have a substituent, the substituent that the cycloalkenyl group may have may be the same as the substituent in the alkyl group which may have a substituent. The alkynyl group exemplified in the organic group W may be either linear or branched. The carbon number of the above alkynyl group is preferably 2 to 20. In the alkynyl group which may have a substituent, the substituent that the alkynyl group may have may be the same as the substituent in the alkyl group which may have a substituent. The carbon number of the cycloalkynyl group exemplified in the organic group W is preferably 5 to 20. In the cycloalkynyl group which may have a substituent, the substituent that the cycloalkynyl group may have may be the same as the substituent in the alkyl group which may have a substituent.

Unless otherwise specified, the aryl group exemplified in the organic group W may be either monocyclic or polycyclic (e.g., 2-6 rings, etc.). The number of ring member atoms of the above aryl group is preferably 6-15, more preferably 6-10. As the above aryl group, phenyl, naphthyl or anthracenyl is preferred, and phenyl is more preferred. In the aryl group that may have a substituent, the substituent that the aryl group may have can be the same as the substituent in the alkyl group that may have a substituent. In addition, in the group exemplified in the organic group W, the aryl part in the substituent containing an aryl group (e.g., aryloxy group) can also be the same as the aryl group exemplified in the above organic group W.

Unless otherwise specified, the heteroaryl group exemplified in the organic group W may be either monocyclic or polycyclic (e.g., 2 to 6 rings, etc.). The number of heteroatoms that the heteroaryl group has as ring member atoms is, for example, 1 to 10. As the above-mentioned heteroatoms, for example, nitrogen atoms, sulfur atoms, oxygen atoms, selenium atoms, tellurium atoms, phosphorus atoms, silicon atoms, and boron atoms can be cited. The number of ring member atoms of the above-mentioned heteroaryl group is preferably 5 to 15. In the heteroaryl group that may have a substituent, the substituent that the heteroaryl group may have can be the same as the substituent in the alkyl group that may have a substituent.

The heterocyclic ring exemplified in the organic group W means a ring containing a heteroatom as a ring member atom, and unless otherwise specified, it may be any of an aromatic heterocyclic ring and an aliphatic heterocyclic ring, and may be any of a monocyclic ring and a polycyclic ring (for example, 2 to 6 rings, etc.). The number of heteroatoms that the heterocyclic ring has as a ring member atom is, for example, 1 to 10. As the above-mentioned heteroatoms, for example, nitrogen atoms, sulfur atoms, oxygen atoms, selenium atoms, tellurium atoms, phosphorus atoms, silicon atoms, and boron atoms can be cited. The number of ring member atoms of the above-mentioned heterocyclic ring is preferably 5 to 15. In the heterocyclic ring that may have a substituent, the substituent that the heterocyclic ring may have can be the same as the substituent in the alkyl group that may have a substituent.

As the lactone group exemplified in the organic group W, a lactone group having 5 to 7 ring members is preferred, and a lactone group having 5 to 7 ring members and having another ring structure condensed on the lactone ring to form a bicyclic structure or a spirocyclic structure is more preferred. In the lactone group which may have a substituent, the substituents which the lactone group may have may be the same as those in the alkyl group which may have a substituent.

R ¹ is preferably a hydrogen atom.

^R1 may bond with ^W1 to form a ring. The ring formed by bonding ^R1 and ^W1 is not particularly limited, and may be either a monocyclic or polycyclic ring. The ring may contain a heteroatom such as an oxygen atom, a nitrogen atom, or a sulfur atom as a ring member. The ring may contain a carbonyl carbon as a ring member. The ring is preferably a 5- or 6-membered alicyclic ring.

Specific examples of the repetitive unit represented by (a1) are given below, but the present invention is not limited to these.

[Chemical formula 3]

In the resin (A), the content of the repeating unit represented by (a1) is preferably 20 mol% or more, more preferably 30 mol% or more, and further preferably 40 mol% or more relative to all repeating units. In addition, the content of the repeating unit represented by (a1) is preferably 90 mol% or less, more preferably 80 mol% or less, further preferably 70 mol% or less, and particularly preferably 60 mol% or less relative to all repeating units. In the resin (A), the repeating unit represented by (a1) may contain one type alone or two or more types. When containing two or more types, it is preferred that the total content is within the above range.

<At least one repeating unit selected from the group consisting of a repeating unit represented by formula (a2) and a repeating unit represented by formula (a3)> In formula (a2), ^X2 represents an alkyl group. The carbon number of the alkyl group as ^X2 is preferably 1 to 20, more preferably 1 to 10, and further preferably 1 to 6. The alkyl group may be any of a linear chain and a branched chain. Examples of the alkyl group include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, and an n-hexyl group. The alkyl group may have a substituent, and examples of the substituent include the groups exemplified by the substituent T mentioned above.

In formula (a2), ^W2 represents an aromatic group. The description, specific examples, and preferred range of ^W2 are the same as the description, specific examples, and preferred range of ^W1 in the above-mentioned (a1).

In formula (a2), R ² represents a hydrogen atom or a substituent. The description, specific examples, and preferred range of R ² are the same as the description, specific examples, and preferred range of R ¹ in the above (a1).

^R2 may bond with ^{X2 or W2} to form a ring. The ring formed by bonding with ^X2 or ^W2 is not particularly limited, and may be either a monocyclic or polycyclic ring. The ring may contain a heteroatom such as an oxygen atom, a nitrogen atom, a sulfur atom, etc. as a ring member atom. In addition, the ring may contain a carbonyl carbon as a ring member atom. The ring is preferably a 5- or 6-membered alicyclic ring.

Specific examples of the repeating unit represented by formula (a2) are given below, but the present invention is not limited thereto.

[Chemical formula 4]

The content of the repeating unit represented by formula (a2) in the resin (A) is preferably 10 mol% or more, more preferably 20 mol% or more, and further preferably 30 mol% or more relative to all repeating units. In addition, the content of the repeating unit represented by formula (a2) is preferably 80 mol% or less, more preferably 70 mol% or less, and further preferably 60 mol% or less relative to all repeating units. In the resin (A), the repeating unit represented by formula (a2) may contain one type alone or two or more types. When containing two or more types, it is preferred that the total content is within the above range.

In formula (a3), ^X3 represents a halogen atom, a cyano group, ^-COORA1 , ^-OCORA2 , _-SO2RA3 , or an alkyl ^group.RA1 , ^{RA2 ,} and ^RA3 each independently represent an organic group.

The halogen atom for X ³ is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

The carbon number of the alkyl group as ^X3 is preferably 1 to 20, more preferably 1 to 10, and further preferably 1 to 6. The alkyl group may be either linear or branched. Examples of the alkyl group include linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, and n-hexyl. The alkyl group may have a substituent, and examples of the substituent include the groups exemplified above as the substituent T.

The organic groups of ^RA1 , ^RA2 and ^RA3 are not particularly limited, and for example, the groups exemplified in the above-mentioned organic group W can be mentioned.

In formula (a3), R ³ represents a hydrogen atom or a substituent. The description, specific examples, and preferred range of R ³ are the same as the description, specific examples, and preferred range of R ¹ in the above (a1).

R ³ may bond with X ³ or W ³ to form a ring. The ring formed by bonding R ³ with X ³ or W ³ is not particularly limited, and may be either a monocyclic or polycyclic ring. The ring may contain an oxygen atom, a nitrogen atom, a sulfur atom or other heteroatoms as a ring member atom. In addition, the ring may contain a carbonyl carbon as a ring member atom. The ring is preferably a 5- or 6-membered alicyclic ring.

In formula (a3), L ¹ represents a linking group. L ¹ preferably represents -O- or -NR ⁴ -. R ⁴ represents a hydrogen atom or an organic group. The organic group is not particularly limited, and examples thereof include the groups exemplified in the organic group W. L ¹ particularly preferably represents -O-.

In formula (a3), W ³ represents an organic group. The organic group is not particularly limited, and examples thereof include the groups exemplified above for the organic group W. W ³ preferably represents an alkyl group, a cycloalkyl group, or an aryl group.

Specific examples of the repeating unit represented by formula (a3) are given below, but the present invention is not limited thereto.

[Chemical formula 5]

The content of the repeating unit represented by formula (a3) in the resin (A) is preferably 10 mol% or more, more preferably 20 mol% or more, and further preferably 30 mol% or more relative to all repeating units. In addition, the content of the repeating unit represented by formula (a3) is preferably 80 mol% or less, more preferably 70 mol% or less, and further preferably 60 mol% or less relative to all repeating units. In the resin (A), the repeating unit represented by formula (a3) may contain one type alone or two or more types. When containing two or more types, it is preferred that the total content is within the above range.

In the resin (A), the content of the repeating unit represented by formula (a1)/the content of the repeating unit represented by formula (a2) is preferably 30/70 to 70/30, more preferably 40/60 to 60/40 in molar ratio.

When the resin (A) contains the repeating unit represented by the formula (a3), the content of the repeating unit represented by (a1)/the content of the repeating unit represented by the formula (a3) is preferably 30/70 to 70/30, more preferably 40/60 to 60/40 in molar ratio.

The resin (A) may contain other repeating units besides the above-mentioned repeating units within the range not affecting the effects of the present invention.

The resin (A) preferably has an interactive group that interacts with the ionic compound (B) described later. Since the resin (A) has an interactive group that interacts with the ionic compound (B), the unexposed portion of the photoresist film formed using the photoresist composition of the present invention is difficult to dissolve in the developer. On the other hand, after exposure, the main chain of the resin (A) decomposes (is cut), and the interaction between the resin (A) and the ionic compound (B) is released, so it tends to be easily dissolved in the developer. That is, it is believed that due to the above-mentioned effect, the dissolution contrast between the unexposed portion and the exposed portion in the photoresist film becomes higher, thereby further improving the LWR performance. Examples of the above-mentioned interactive group include hydroxyl groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), carboxyl groups, sulfonic acid groups, alkoxy groups, amide groups, and sulfonamide groups, and phenolic hydroxyl groups or carboxyl groups are preferred. The above-mentioned phenolic hydroxyl group refers to a hydroxyl group substituted by a ring member atom of an aromatic ring (aromatic hydrocarbon ring and aromatic heterocyclic ring). The above-mentioned alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms. The above-mentioned amide group is not particularly limited, and an example thereof includes -C(=O)-NHR ^P (R ^P represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms). The above-mentioned sulfonamide group is not particularly limited, and an example thereof includes -SO ₂ -NHR ^P (R ^P represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms).

The weight average molecular weight of the resin (A) is preferably 5,000 or more, more preferably 10,000 or more, and further preferably 20,000 or more. In addition, the weight average molecular weight of the resin (A) is preferably 200,000 or less, more preferably 150,000 or less, further preferably 100,000 or less, and particularly preferably 85,000 or less. The above weight average molecular weight value is a value obtained by the GPC method as a polystyrene conversion value. The dispersion degree (molecular weight distribution) of the resin (A) is usually 1.0 to 5.0, preferably 1.0 to 3.0, more preferably 1.0 to 3.0, and further preferably 1.0 to 2.5. When the dispersion degree is within the above range, the resolution and resist shape tend to be more excellent.

The resin (A) can be synthesized by conventional methods (e.g., free radical polymerization). Details of the synthesis are shown in the Examples.

In the photoresist composition of the present invention, the content of the resin (A) is preferably 50.0 mass % or more, more preferably 60.0 mass % or more, and further preferably 70.0 mass % or more relative to the total solid content of the photoresist composition. In addition, the upper limit of the content of the resin (A) is 100 mass % or less, preferably 99.9 mass % or less. Resin (A) can be used alone or in combination. When two or more types are used, it is preferred that their total content is within the above-mentioned preferred content range.

<Solvent> The photoresist composition of the present invention preferably contains a solvent. The solvent preferably includes at least one of (M1) and (M2), wherein (M1) is propylene glycol monoalkyl ether carboxylate, and (M2) is at least one selected from the group consisting of propylene glycol monoalkyl ether, lactate, acetate, alkoxy propionate, chain ketone, cyclic ketone, lactone and alkyl carbonate. In addition, the solvent may further contain components other than components (M1) and (M2).

When such a solvent and a resin (A) are used in combination, the coating property of the photoresist composition can be improved, and a pattern with a small number of development defects can be easily formed. The reason for this is presumably that such a solvent is excellent in the balance of the solubility, boiling point and viscosity of the resin (A), and thus can suppress the unevenness of the film thickness of the photoresist film formed by the photoresist composition and the generation of precipitates during spin coating.

The component (M1) is preferably at least one selected from the group consisting of propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether propionate, and propylene glycol monoethyl ether acetate, and more preferably propylene glycol monomethyl ether acetate (PGMEA).

As component (M2), the following components are preferred. As propylene glycol monoalkyl ether, propylene glycol monomethyl ether (PGME) and propylene glycol monoethyl ether (PGEE) are preferred. As lactic acid ester, ethyl lactate, butyl lactate or propyl lactate are preferred. As acetate, methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, propyl acetate, isoamyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate or 3-methoxybutyl acetate are preferred. In addition, butyl butyrate is also preferred. As alkoxypropionate, methyl 3-methoxypropionate (MMP) or ethyl 3-ethoxypropionate (EEP) are preferred. As the chain ketone, 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 2-heptanone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, propiophenone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetone alcohol, acetylmethanol, acetophenone, methyl naphthyl ketone, or methyl amyl ketone are preferred. As the cyclic ketone, methyl cyclohexanone, isophorone, cyclopentanone, or cyclohexanone are preferred. As the lactone, γ-butyrolactone is preferred. As the alkyl carbonate, propyl carbonate is preferred.

As the component (M2), propylene glycol monomethyl ether (PGME), ethyl lactate, ethyl 3-ethoxypropionate, methyl amyl ketone, cyclohexanone, butyl acetate, amyl acetate, γ-butyrolactone, or propylene carbonate is more preferred.

As a solvent, in addition to the above components, it is also preferred to contain an ester solvent having a carbon number of 7 or more (preferably 7 to 14, more preferably 7 to 12, and further preferably 7 to 10) and a heteroatom number of 2 or less. As an ester solvent having a carbon number of 7 or more and a heteroatom number of 2 or less, amyl acetate, 2-methylbutyl acetate, 1-methylbutyl acetate, hexyl acetate, amyl propionate, hexyl propionate, butyl propionate, isobutyl isobutyrate, heptyl propionate, or butyl butyrate is preferred, and isoamyl acetate is more preferred.

As component (M2), preferably, the flash point (hereinafter, also referred to as fp) is 37°C or above. As such component (M2), preferably, propylene glycol monomethyl ether (fp: 47°C), ethyl lactate (fp: 53°C), ethyl 3-ethoxypropionate (fp: 49°C), methyl amyl ketone (fp: 42°C), cyclohexanone (fp: 44°C), amyl acetate (fp: 45°C), methyl 2-hydroxyisobutyrate (fp: 45°C), γ-butyrolactone (fp: 101°C), or propylene carbonate (fp: 132°C). Among them, more preferably, propylene glycol monoethyl ether, ethyl lactate, amyl acetate or cyclohexanone, and more preferably, propylene glycol monoethyl ether or ethyl lactate. In addition, the so-called "flash point" here refers to the value listed in the reagent catalog of Tokyo Chemical Industry Co., Ltd. or Sigma-Aldrich Corporation.

The solvent preferably contains component (M1). The solvent preferably consists essentially of component (M1) alone, or is a mixed solvent of component (M1) and other components. In the latter case, the solvent more preferably contains both component (M1) and component (M2). The mass ratio (M1/M2) of component (M1) to component (M2) is preferably in the range of "100/0" to "15/85", more preferably in the range of "100/0" to "40/60", and further preferably in the range of "100/0" to "60/40". That is, the solvent preferably contains only component (M1), or contains both component (M1) and component (M2), and the mass ratio is as shown below. That is, in the latter case, the mass ratio of component (M1) to component (M2) is preferably 15/85 or more, more preferably 40/60 or more, and further preferably 60/40 or more. By adopting this structure, the number of development defects can be further reduced.

When the solvent contains both the component (M1) and the component (M2), the mass ratio of the component (M1) to the component (M2) may be, for example, 99/1 or less.

When the solvent further contains components other than components (M1) and (M2), the content of the components other than components (M1) and (M2) is preferably 5 to 30 mass % based on the total amount of the solvent.

The content of the solvent in the photoresist composition of the present invention is preferably set to a solid component concentration of 0.5 to 30 mass %, more preferably 1 to 20 mass %, from the viewpoint of having better coating properties.

[Other components] The photoresist composition of the present invention may contain other components besides the resin (A) and the solvent. There is no particular limitation on other components, and examples thereof include ionic compounds (specifically, photodegradable onium salt compounds) and surfactants.

<Ionic compound (B)> The photoresist composition of the present invention preferably further contains an ionic compound (B). The ionic compound (B) may be a compound that decomposes by irradiation with actinic rays or radiation, or a compound that does not decompose. The compound that decomposes by irradiation with actinic rays or radiation may be a compound that decomposes by irradiation with actinic rays or radiation to generate an acid, or a compound that decomposes by irradiation with actinic rays or radiation to generate a base. As the ionic compound (B), a compound having an onium salt structure that generates an acid by irradiation with actinic rays or radiation (photodegradable onium salt compound) is preferred. When the photoresist composition contains a photodegradable onium salt compound or a plasma compound, in the unexposed portion, the resin (A) is easily condensed with the ionic compound (B) by the interactive group that can be contained in the resin (A). On the other hand, the above-mentioned condensed structure can be released by causing dissociation between the ionic compound (B) and the interactive group or cracking of the photodegradable onium salt compound when exposed. That is, by the above-mentioned action, the dissolution contrast between the unexposed portion and the exposed portion in the photoresist film is further improved, thereby making the effect of the present invention more excellent. In addition, when the photoresist composition contains a photodegradable onium salt compound or a plasma compound (B), the resin (A) contained in the photoresist composition preferably has an interactive group. As the interactive group, there can be cited the above-mentioned hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group, etc.), carboxyl group, sulfonic acid group, amide group, and sulfonamide group, etc.

The photodegradable onium salt compound is described below. The photodegradable onium salt compound is preferably a compound having at least one salt structure site composed of an anion site and a cation site, and generating an acid (preferably an organic acid) by decomposition by exposure. The above-mentioned salt structure site of the photodegradable onium salt compound is preferably composed of an organic cation site and an organic anion site with extremely low nucleophilicity, from the viewpoint that it is easy to decompose by exposure and the generation of organic acid is more excellent. The above-mentioned salt structure site may be a part of the photodegradable onium salt compound, or may be the whole. In addition, when the salt structure part is a part of the photodegradable onium salt compound, for example, as in the photodegradable onium salt PG2 described later, it is equivalent to a structure obtained by linking two or more salt structure parts. The number of salt structure parts in the photodegradable onium salt is not particularly limited, and is preferably 1 to 10, more preferably 1 to 6, and further preferably 1 to 3.

As the organic acid generated by the photodegradable onium salt compound by the above-mentioned exposure, for example, sulfonic acid (aliphatic sulfonic acid, aromatic sulfonic acid, camphorsulfonic acid, etc.), carboxylic acid (aliphatic carboxylic acid, aromatic carboxylic acid, aralkyl carboxylic acid, etc.), carbonylsulfonyl imide acid, bis(alkylsulfonyl)imidic acid, and tris(alkylsulfonyl)methide acid, etc. can be cited. In addition, the organic acid generated by the photodegradable onium salt compound by the exposure can be a polybasic acid having two or more acid groups. For example, when the photodegradable onium salt compound is the photodegradable onium salt compound PG2 described later, the organic acid generated by decomposition of the photodegradable onium salt compound by exposure becomes a polybasic acid having two or more acid groups.

In the photodegradable onium salt compound, the cationic site constituting the salt structure site is preferably an organic cationic site, and among them, the organic cation represented by the formula (ZaI) (cation (ZaI)) or the organic cation represented by the formula (ZaII) (cation (ZaII)) described later is preferred.

(Photodegradable onium salt compound PG1) As an example of a preferred embodiment of the photodegradable onium salt compound, there can be cited an onium salt compound represented by "M ⁺ X ^- " and generating an organic acid by exposure (hereinafter also referred to as "photodegradable onium salt compound PG1"). In the compound represented by "M ⁺ X ^- ", M ⁺ represents an organic cation, and X ^- represents an organic anion. The photodegradable onium salt compound PG1 is described below.

The organic cation represented by M ⁺ in the photodegradable onium salt compound PG1 is preferably an organic cation represented by formula (ZaI) (cation (ZaI)) or an organic cation represented by formula (ZaII) (cation (ZaII)).

[Chemical formula 6]

In the above formula (ZaI), R ²⁰¹ , R ²⁰² and R ²⁰³ each independently represent an organic group. The carbon number of the organic group of R ²⁰¹ , R ²⁰² and R ²⁰³ is usually 1 to 30, preferably 1 to 20. In addition, two of R ²⁰¹ to R ²⁰³ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester group, an amide group or a carbonyl group. Examples of the group formed by two of R ²⁰¹ to R ²⁰³ bonding include an alkylene group (e.g., a butylene group and a pentylene group) and -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -.

Preferred examples of the organic cation in formula (ZaI) include cation (ZaI-1), cation (ZaI-2), an organic cation represented by formula (ZaI-3b) (cation (ZaI-3b)), and an organic cation represented by formula (ZaI-4b) (cation (ZaI-4b)) described later.

First, the cation (ZaI-1) is explained. The cation (ZaI-1) is an aryl zirconia cation, wherein at least one of R ²⁰¹ to R ²⁰³ in the above formula (ZaI) is an aryl zirconia cation. In the aryl zirconia cation, R ²⁰¹ to R ²⁰³ may all be aryl groups, or some of R ²⁰¹ to R ²⁰³ may be aryl groups and the rest may be alkyl groups or cycloalkyl groups. Furthermore, one of R ²⁰¹ to R ²⁰³ may be an aryl group, and the remaining two of R ²⁰¹ to R ²⁰³ may be bonded to form a ring structure, or an oxygen atom, a sulfur atom, an ester group, an amide group or a carbonyl group may be contained in the ring. Examples of the group formed by two of R ²⁰¹ to R ²⁰³ being bonded include alkylene groups in which one or more methylene groups may be substituted with an oxygen atom, a sulfur atom, an ester group, an amide group, and/or a carbonyl group (e.g., butylene, pentylene, or -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -). Examples of the arylzirconia cation include triarylzirconia cations, diarylalkylzirconia cations, aryldialkylzirconia cations, diarylcycloalkylzirconia cations, and aryldicycloalkylzirconia cations.

The aromatic group contained in the aromatic coronium cation is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aromatic group may be an aromatic group having a heterocyclic structure containing an oxygen atom, a nitrogen atom, or a sulfur atom. Examples of the heterocyclic structure include a pyrrole residue, a furan residue, a thiophene residue, an indole residue, a benzofuran residue, and a benzothiophene residue. When the aromatic coronium cation has two or more aromatic groups, the two or more aromatic groups may be the same or different. The arylthium cation may optionally have an alkyl or cycloalkyl group, preferably a linear alkyl group having 1 to 15 carbon atoms, a branched alkyl group having 3 to 15 carbon atoms, or a cycloalkyl group having 3 to 15 carbon atoms, more preferably, for example, methyl, ethyl, propyl, n-butyl, sec-butyl, t-butyl, cyclopropyl, cyclobutyl, and cyclohexyl.

As substituents that the aryl, alkyl and cycloalkyl groups of R ²⁰¹ to R ²⁰³ may have, each independently preferably an alkyl group (e.g., having 1 to 15 carbon atoms), a cycloalkyl group (e.g., having 3 to 15 carbon atoms), an aryl group (e.g., having 6 to 14 carbon atoms), an alkoxy group (e.g., having 1 to 15 carbon atoms), a cycloalkylalkoxy group (e.g., having 1 to 15 carbon atoms), a halogen atom (e.g., fluorine, iodine), a hydroxyl group, a carboxyl group, an ester group, a sulfinyl group, a sulfonyl group, an alkylthio group, and a phenylthio group. The above substituents may further have substituents, and for example, the above alkyl group may have a halogen atom as a substituent, and may be a halogenated alkyl group such as a trifluoromethyl group.

Next, the cation (ZaI-2) will be described. The cation (ZaI-2) is a cation in which R ²⁰¹ to R ²⁰³ in the formula (ZaI) each independently represent an organic group having no aromatic ring. The aromatic ring herein also includes an aromatic ring containing a heteroatom. The organic group having no aromatic ring as R ²⁰¹ to R ²⁰³ usually has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. R ²⁰¹ to R ²⁰³ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group, or an alkoxycarbonylmethyl group, and further preferably a linear or branched 2-oxoalkyl group.

As the alkyl group and cycloalkyl group of R ²⁰¹ to R ²⁰³ , for example, there can be mentioned a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms (for example, methyl, ethyl, propyl, butyl and pentyl), and a cycloalkyl group having 3 to 10 carbon atoms (for example, cyclopentyl, cyclohexyl and norbornyl). R ²⁰¹ to R ²⁰³ may be further substituted by a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

Next, the cation (ZaI-3b) will be described. The cation (ZaI-3b) is a cation represented by the following formula (ZaI-3b).

[Chemical formula 7]

In formula (ZaI-3b), R _1c to R _5c each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, a hydroxyl group, a nitro group, an alkylthio group, or an arylthio group. R _6c and R _7c each independently represent a hydrogen atom, an alkyl group (such as tert-butyl group), a cycloalkyl group, a halogen atom, a cyano group, or an aryl group. R _x and R _y each independently represent an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonylalkyl group, an allyl group, or a vinyl group.

Any two or more of R _1c to R _5c , R _5c and R _6c , R _6c and R _7c , R _5c and R _x , and R _x and R _y may be bonded to each other to form a ring, and the ring may independently contain an oxygen atom, a sulfur atom, a ketone group, an ester bond, or an amide bond. Examples of the above-mentioned ring include aromatic or non-aromatic hydrocarbon rings, aromatic or non-aromatic heterocyclic rings, and polycyclic condensed rings formed by combining two or more of these rings. Examples of the ring include 3-10 membered rings, preferably 4-8 membered rings, and more preferably 5- or 6-membered rings.

As the group formed by the bonding of any two or more of R _1c to R _5c , R _6c and R _7c , and R _x and R _y , there can be mentioned alkylene groups such as butylene and pentylene. The methylene group in the alkylene group may be substituted by a heteroatom such as an oxygen atom. As the group formed by the bonding of R _5c and R _6c , and R _5c and R _x , it is preferably a single bond or an alkylene group. As the alkylene group, there can be mentioned methylene and ethylene.

R _1c to R _5c , R _6c , R _7c , R _x , R _y , and a ring formed by any two or more of R _1c to R _5c , R _5c and R _6c , R _6c and R _7c , R _5c and R _x , and R _x and R _y bonding to each other may have a substituent.

Next, the cation (ZaI-4b) will be described. The cation (ZaI-4b) is a cation represented by the following formula (ZaI-4b).

[Chemical formula 8]

In formula (ZaI-4b), l represents an integer of 0 to 2. r represents an integer of 0 to 8. R ₁₃ represents a hydrogen atom, a halogen atom (for example, a fluorine atom, an iodine atom, etc.), a hydroxyl group, an alkyl group, a halogenated alkyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, or a group containing a cycloalkyl group (which may be a cycloalkyl group itself or a group containing a portion of a cycloalkyl group). These groups may have a substituent. R ₁₄ represents a hydroxyl group, a halogen atom (for example, a fluorine atom, an iodine atom, etc.), an alkyl group, a halogenated alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylsulfonyl group, a cycloalkylsulfonyl group, or a group containing a cycloalkyl group (which may be a cycloalkyl group itself or a group containing a portion of a cycloalkyl group). These groups may have a substituent. When there are plural R ₁₄ , each independently represents the above-mentioned groups such as a hydroxyl group. R ₁₅ independently represents an alkyl group, a cycloalkyl group or a naphthyl group. Two R _{15 groups} may be bonded to each other to form a ring. When two R ₁₅ groups are bonded to each other to form a ring, the ring skeleton may contain a heteroatom such as an oxygen atom or a nitrogen atom. In one embodiment, it is preferred that two R ₁₅ groups are alkylene groups and are bonded to each other to form a ring structure. In addition, the above-mentioned alkyl group, the above-mentioned cycloalkyl group and the above-mentioned naphthyl group, and the ring formed by two R ₁₅ groups being bonded to each other may have a substituent.

In formula (ZaI-4b), the alkyl groups of R ₁₃ , R ₁₄ and R ₁₅ are preferably linear or branched. The carbon number of the alkyl group is preferably 1 to 10. More preferably, the alkyl group is methyl, ethyl, n-butyl or t-butyl.

Next, the formula (ZaII) is described. In the formula (ZaII), R ²⁰⁴ and R ²⁰⁵ each independently represent an aryl group, an alkyl group, or a cycloalkyl group. As the aryl group of R ²⁰⁴ and R ²⁰⁵ , a phenyl group or a naphthyl group is preferred, and a phenyl group is more preferred. The aryl group of R ²⁰⁴ and R ²⁰⁵ may be an aryl group having a heterocyclic ring, and the heterocyclic ring has an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Examples of the skeleton of the aryl group having a heterocyclic ring include pyrrole, furan, thiophene, indole, benzofuran, and benzothiophene. The alkyl group and cycloalkyl group for R ²⁰⁴ and R ²⁰⁵ are preferably a linear alkyl group having 1 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms (e.g., methyl, ethyl, propyl, butyl or pentyl), or a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl or norbornyl).

The aryl group, alkyl group and cycloalkyl group represented by R ²⁰⁴ and R ²⁰⁵ may each independently have a substituent. Examples of the substituent that the aryl group, alkyl group and cycloalkyl group represented by R ²⁰⁴ and R ²⁰⁵ may have include an alkyl group (e.g., having 1 to 15 carbon atoms), a cycloalkyl group (e.g., having 3 to 15 carbon atoms), an aryl group (e.g., having 6 to 15 carbon atoms), an alkoxy group (e.g., having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group and a phenylthio group.

Specific examples of the organic cation represented by M ⁺ are shown below, but the present invention is not limited thereto.

[Chemical formula 9]

[Chemical formula 10]

[Chemical formula 11]

As the organic anion represented by ^X- in the photodegradable onium salt compound PG1, a non-nucleophilic anion (anion having extremely low ability to cause a nucleophilic reaction) is preferred. Examples of the non-nucleophilic anion include sulfonic acid anions (aliphatic sulfonic acid anions, aromatic sulfonic acid anions, and camphorsulfonic acid anions), carboxylic acid anions (aliphatic carboxylic acid anions, aromatic carboxylic acid anions, and aralkyl carboxylic acid anions), sulfonimide anions, bis(alkylsulfonyl)imide anions, and tris(alkylsulfonyl)methide anions.

As the organic anion, for example, an organic anion represented by the following formula (DA) is also preferred.

[Chemical formula 12]

In formula (DA), A ^31- represents an anionic group. R _a1 represents a hydrogen atom or a monovalent organic group. L _a1 represents a single bond or a divalent linking group. A ^31- and R _a1 may be bonded to each other to form a ring.

A ^31- represents an anionic group. The anionic group represented by A ^31- is not particularly limited, and for example, it is preferably a group selected from the group consisting of groups represented by formulas (BA-1) to (BA-14), and more preferably formulas (BA-1), (BA-2), (BA-3), (BA-4), (BA-5), (BA-6), (BA-10), (BA-12), (BA-13), and (BA-14).

[Chemical formula 13]

In formula (BA-1) to (BA-14), * represents a bonding position. In formula (BA-1) to (BA-5) and formula (BA-12), ^RX1 each independently represents a monovalent organic group. In formula (BA-7) and (BA-11), ^RX2 each independently represents a hydrogen atom, or a fluorine atom and a substituent other than a perfluoroalkyl group. The two ^RX2 in formula (BA-7) may be the same or different. In formula (BA-8), ^RXF1 represents a hydrogen atom, a fluorine atom or a perfluoroalkyl group. Among them, at least one of the two ^RXF1 represents a fluorine atom or a perfluoroalkyl group. The two ^RXF1 in formula (BA-8) may be the same or different. In formula (BA-9), ^RX3 represents a hydrogen atom, a halogen atom or a monovalent organic group. n1 represents an integer from 0 to 4. When n1 represents an integer of 2 to 4, a plurality of ^RX3 may be the same or different. In formula (BA-10), ^RXF2 represents a fluorine atom or a perfluoroalkyl group. The object to be bonded to the bonding position represented by * in formula (BA-14) is preferably a phenylene group which may have a substituent. Examples of the substituent that the phenylene group may have include a halogen atom and the like.

In formulae (BA-1) to (BA-5) and (BA-12), ^RX1 independently represents a monovalent organic group. ^RX1 is preferably an alkyl group (may be linear or branched, preferably having 1 to 15 carbon atoms), a cycloalkyl group (may be monocyclic or polycyclic, preferably having 3 to 20 carbon atoms), or an aryl group (may be monocyclic or polycyclic, preferably having 6 to 20 carbon atoms). The above groups represented by ^RX1 may have a substituent. In formula (B-5), the atom directly bonded to N- in ^RX1 is preferably any one of a carbon atom other than -CO- and a sulfur atom in -SO ₂ -.

The cycloalkyl group in ^RX1 may be monocyclic or polycyclic. Examples of the cycloalkyl group in ^RX1 include norbornyl and adamantyl.

The substituent that the cycloalkyl group in ^RX1 may have is not particularly limited, but is preferably an alkyl group (which may be linear or branched, preferably having 1 to 5 carbon atoms). One or more carbon atoms among the carbon atoms that are ring members of the cycloalkyl group in ^RX1 may be substituted by a carbonyl carbon atom.

The carbon number of the alkyl group in ^RX1 is preferably 1 to 10, more preferably 1 to 5. The substituent that the alkyl group in ^RX1 may have is not particularly limited, and for example, a cycloalkyl group, a fluorine atom or a cyano group is preferred. Examples of the cycloalkyl group as the substituent are the same as those described when ^RX1 is a cycloalkyl group. When the alkyl group in ^RX1 has a fluorine atom as the substituent, the alkyl group may be a perfluoroalkyl group. Furthermore, one or more _-CH2- groups in the alkyl group in ^RX1 may be substituted with a carbonyl group.

The aryl group in ^RX1 is preferably a phenyl group. The substituent that the aryl group in ^RX1 may have is not particularly limited, but is preferably an alkyl group, a fluorine atom or a cyano group. Examples of the alkyl group as the substituent are the same as those described above when ^RX1 is an alkyl group.

In formula (BA-7) and (BA-11), ^RX2 each independently represents a hydrogen atom, or a fluorine atom and a substituent other than a perfluoroalkyl group (for example, an alkyl group not containing a fluorine atom and a cycloalkyl group not containing a fluorine atom can be mentioned). The two ^RX2 in formula (BA-7) may be the same or different.

In formula (BA-8), ^RXF1 represents a hydrogen atom, a fluorine atom or a perfluoroalkyl group. At least one of the plurality of ^RXF1 represents a fluorine atom or a perfluoroalkyl group. The two ^RXF1 in formula (BA-8) may be the same or different. The carbon number of the perfluoroalkyl group represented by ^RXF1 is preferably 1 to 15, more preferably 1 to 10, and even more preferably 1 to 6.

In formula (BA-9), ^RX3 represents a hydrogen atom, a halogen atom or a monovalent organic group. As the halogen atom of ^RX3 , for example, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom can be cited, among which a fluorine atom is preferred. The monovalent organic group as ^RX3 is the same as the monovalent organic group recorded as ^RX1 . n1 represents an integer of 0 to 4. n1 is preferably an integer of 0 to 2, and more preferably 0 or 1. When n1 represents an integer of 2 to 4, a plurality of ^RX3 may be the same or different.

In formula (BA-10), ^RXF2 represents a fluorine atom or a perfluoroalkyl group. The perfluoroalkyl group represented by ^RXF2 preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 6 carbon atoms.

In formula (DA), the carbon number of the monovalent organic group of R _a1 is not particularly limited, and preferably has 1 to 30 carbon atoms, and more preferably has 1 to 20 carbon atoms. R _a1 is preferably an alkyl group, a cycloalkyl group, or an aryl group. As an alkyl group, it may be a linear or branched chain, and is preferably an alkyl group having 1 to 20 carbon atoms, and more preferably an alkyl group having 1 to 15 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. As a cycloalkyl group, it may be a monocyclic or polycyclic group, and is preferably a cycloalkyl group having 3 to 20 carbon atoms, and more preferably a cycloalkyl group having 3 to 15 carbon atoms, and more preferably a cycloalkyl group having 3 to 10 carbon atoms. The aryl group may be monocyclic or polycyclic, preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 15 carbon atoms, and further preferably an aryl group having 6 to 10 carbon atoms. The cycloalkyl group may contain a heteroatom as a ring member atom. There is no particular limitation on the heteroatom, and examples thereof include nitrogen atoms, oxygen atoms, etc. In addition, the cycloalkyl group may contain a carbonyl bond (>C=O) as a ring member atom. The above-mentioned alkyl group, cycloalkyl group and aryl group may further have a substituent. In addition, A ^31- and R _a1 may be bonded to each other to form a ring.

The divalent linking group of L _a1 is not particularly limited, and examples thereof include alkylene groups, cycloalkylene groups, aromatic groups, -O-, -CO-, -COO-, and groups formed by combining two or more of these groups. The alkylene group may be a linear or branched chain, preferably having 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms. The cycloalkylene group may be a monocyclic or polycyclic group, preferably having 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms. The aromatic group is a divalent aromatic group, preferably an aromatic group having 6 to 20 carbon atoms, more preferably an aromatic group having 6 to 15 carbon atoms. The aromatic ring constituting the aromatic group is not particularly limited, and for example, an aromatic ring having 6 to 20 carbon atoms can be cited, and specifically, a benzene ring, a naphthalene ring, an anthracene ring, and a thiophene ring can be cited. As the aromatic ring constituting the aromatic group, a benzene ring or a naphthalene ring is preferred, and a benzene ring is more preferred. The alkylene group, the cycloalkylene group, and the aromatic group may further have a substituent, and a halogen atom is preferred as the substituent. L _a1 preferably represents a single bond.

As the photodegradable onium salt compound PG1, for example, it is also preferable to use the photoacid generator disclosed in paragraphs [0135] to [0171] of International Publication No. 2018/193954, paragraphs [0077] to [0116] of International Publication No. 2020/066824, and paragraphs [0018] to [0075] and [0334] to [0335] of International Publication No. 2017/154345.

The molecular weight of the photodegradable onium salt compound PG1 is preferably 3,000 or less, more preferably 2,000 or less, and further preferably 1,000 or less.

(Photodegradable onium salt compound PG2) In addition, as another preferred example of the photodegradable onium salt compound, the following compound (I) and compound (II) can be cited (hereinafter, "compound (I) and compound (II)" are also referred to as "photodegradable onium salt compound PG2"). The photodegradable onium salt compound PG2 is a compound having two or more of the above-mentioned salt structure parts and generating a polyvalent organic acid by exposure. The photodegradable onium salt compound PG2 is described below.

<<Compound (I)>> Compound (I) is a compound having one or more of the following structural sites X and one or more of the following structural sites Y, and is a compound that generates an acid comprising the following first acid site derived from the following structural site X and the following second acid site derived from the following structural site Y by irradiation with actinic rays or radiation. Structural site X: A structural site consisting of anionic site A ₁ ^- and cationic site M ₁ ⁺ , and forming a first acid site represented by HA ₁ by irradiation with actinic rays or radiation Structural site Y: A structural site consisting of anionic site A ₂ ^- and cationic site M ₂ ⁺ , and forming a second acid site represented by HA ₂ by irradiation with actinic rays or radiation Wherein, compound (I) satisfies the following condition I.

Condition I: In the compound (1), the compound PI obtained by replacing the cationic site _M1 ⁺ in the structural site X and the cationic site _M2 ⁺ in the structural site Y with H ⁺ has an acid dissociation constant a1 derived from the acidic site represented by _HA1 obtained by replacing the cationic site _M1 ⁺ in the structural site X with H ⁺ , and an acid dissociation constant a2 derived from the acidic site represented by _HA2 obtained by replacing the cationic site _M2 ⁺ in the structural site Y with H ⁺ , and the acid dissociation constant a2 is greater than the acid dissociation constant a1. The compound PI is equivalent to an acid generated when the compound (I) is irradiated with actinic rays or radiation.

When compound (I) has two or more structural moieties X, the structural moieties X may be the same or different. Furthermore, the two or more A ₁ ^- and the two or more M ₁ ⁺ may be the same or different. Furthermore, in compound (I), the A ₁ ^- and the A ₂ ^- , and the M ₁ ⁺ and the M ₂ ⁺ may be the same or different, but the A ₁ ^- and the A ₂ ^- are preferably different.

The anionic site A ₁ ^- and the anionic site A ₂ ^- are structural sites containing negatively charged atoms or atomic groups, and examples thereof include structural sites selected from the group consisting of the following formulae (AA-1) to (AA-3) and (BB-1) to (BB-6). In the following formulae (AA-1) to (AA-3) and (BB-1) to (BB-6), * represents a bonding position. ^RA represents a monovalent organic group. Examples of the monovalent organic group represented by ^RA include cyano, trifluoromethyl, and methanesulfonyl.

[Chemical formula 14]

[Chemical formula 15]

The cationic site _M1 ⁺ and the cationic site _M2 ⁺ are structural sites containing positively charged atoms or atomic groups, and examples thereof include monovalent organic cations. The organic cations are not particularly limited, but are preferably organic cations represented by the above formula (ZaI) (cations (ZaI)) or organic cations represented by the formula (ZaII) (cations (ZaII)).

《Compound (II)》 Compound (II) is a compound having two or more of the above-mentioned structural sites X and one or more of the following structural sites Z, and is a compound that generates an acid containing two or more of the above-mentioned first acid sites derived from the above-mentioned structural site X and the above-mentioned structural site Z by irradiation with actinic rays or radiation. Structural site Z: a non-ionic site capable of neutralizing an acid

The compound (II) is irradiated with actinic rays or radiation to produce a compound PII (acid) having an acidic site represented by HA ₁ obtained by replacing the cationic site M ₁ ⁺ in the structural site X with H ⁺ . That is, the compound PII represents a compound having the acidic site represented by HA ₁ and a structural site Z that is a non-ionic site capable of neutralizing the acid. In the compound (II), the definition of the structural site X and the definitions of A ₁ ^- and M ₁ ⁺ are the same as those of the structural site X and the definitions of A ₁ ^- and M ₁ ⁺ in the compound (I), and the preferred embodiment is also the same. In addition, the two or more structural sites X may be the same or different. In addition, the two or more A ₁ ^- and the two or more M ₁ ⁺ may be the same or different.

The non-ionic part capable of neutralizing the acid in the structural part Z is not particularly limited, and for example, it is preferably a part containing a group that can electrostatically interact with protons or a functional group having electrons. As the group that can electrostatically interact with protons or the functional group having electrons, there can be cited a functional group having a macrocyclic structure such as a cyclic polyether or a functional group having a nitrogen atom containing a non-shared electron pair that does not contribute to π conjugation. The so-called nitrogen atom containing a non-shared electron pair that does not contribute to π conjugation is, for example, a nitrogen atom having a partial structure shown in the following formula.

[Chemical formula 16] Unshared electron pairs

Examples of the partial structure of the group capable of electrostatically interacting with protons or the functional group having electrons include crown ether structure, nitrogen-doped crown ether structure, primary to tertiary amine structure, pyridine structure, imidazole structure, and pyrazine structure, among which primary to tertiary amine structure is preferred.

The molecular weight of the photodegradable onium salt compound PG2 is preferably 100 to 10,000, more preferably 100 to 2,500, and even more preferably 100 to 1,500.

As the photodegradable onium salt compound PG2, the compounds exemplified in paragraphs [0023] to [0095] of International Publication No. 2020/158313 can be cited.

An example of a site other than a cation that the photodegradable onium salt compound PG2 may have is shown below.

[Chemical formula 17]

[Chemical formula 18]

When the photoresist composition of the present invention contains an ionic compound (B), the content of the ionic compound (B) is not particularly limited, and is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and further preferably 5.0% by mass or more relative to the total solid content of the photoresist composition. In addition, the content of the ionic compound (B) is preferably 50.0% by mass or less, and more preferably 40.0% by mass or less relative to the total solid content of the photoresist composition. The ionic compound (B) can be used alone or in combination of two or more. When two or more are used, it is preferred that the total content is within the above-mentioned preferred content range.

<Hydrophobic resin> The photoresist composition of the present invention may further contain a hydrophobic resin different from the resin (A). The hydrophobic resin is preferably designed to be preferentially present on the surface of the photoresist film, but unlike the surfactant, it does not necessarily have a hydrophilic group in its molecule and may not contribute to the uniform mixing of polar and non-polar substances. As the effects brought about by the addition of the hydrophobic resin, the static and dynamic contact angles of the photoresist film surface relative to the developer and the suppression of outgassing can be cited.

From the perspective of partial localization of the membrane surface, the hydrophobic resin preferably has one or more of fluorine atoms, silicon atoms, and CH ₃ partial structures contained in the side chain of the resin, and more preferably has two or more. The above hydrophobic resin preferably has a alkyl group with a carbon number of 5 or more. These groups may exist in the main chain of the resin or may be substituted in the side chain. As hydrophobic resins, compounds described in paragraphs [0275] to [0279] of International Publication No. 2020/004306 can be cited.

When the photoresist composition of the present invention contains a hydrophobic resin, the content of the hydrophobic resin is preferably 0.01 to 20.0% by mass, and more preferably 0.1 to 15.0% by mass, relative to the total solid content of the photoresist composition. One or more hydrophobic resins may be used. When two or more hydrophobic resins are used, it is preferred that the total content is within the above-mentioned preferred content range.

<Surfactant> The photoresist composition may contain a surfactant. When the surfactant is contained, a pattern with better adhesion and fewer development defects can be formed. The surfactant is preferably a fluorine-based and/or silicon-based surfactant. As the fluorine-based and/or silicon-based surfactant, the surfactant disclosed in paragraphs [0218] and [0219] of International Publication No. 2018/193954 can be cited. When the photoresist composition contains a surfactant, the content of the surfactant is preferably 0.0001 to 2 mass %, and more preferably 0.0005 to 1 mass % relative to the total solid content of the photoresist composition. Only one type of surfactant may be used, or two or more types may be used. When two or more types are used, it is preferred that their combined content be within the above-mentioned preferred content range.

[Photoresist film, pattern forming method] The present invention also relates to a photoresist film formed using the above-mentioned photoresist composition. Furthermore, the present invention also relates to a pattern forming method, which has a process of forming a film using the above-mentioned photoresist composition, a process of exposing the above-mentioned film, and a process of developing the exposed film using a developer.

The steps of the pattern forming method using the above-mentioned photoresist composition are not particularly limited, and preferably have the following processes. Process 1: Process of forming a photoresist film on a substrate using a photoresist composition Process 2: Process of exposing the photoresist film Process 3: Process of developing the exposed photoresist film using a developer containing an organic solvent The steps of each of the above processes will be described in detail below.

<Process 1: Photoresist film forming process> Process 1 is a process for forming a photoresist film on a substrate using a photoresist composition. The definition of the photoresist composition is as described above.

As a method of forming a photoresist film on a substrate using a photoresist composition, for example, a method of coating the photoresist composition on a substrate can be cited. In addition, it is preferred to filter the photoresist composition with a filter as needed before coating. The pore size of the filter is preferably 0.1 μm or less, more preferably 0.05 μm or less, and further preferably 0.03 μm or less. In addition, the filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon.

The photoresist composition can be applied to a substrate (e.g., coated with silicon or silicon dioxide) such as that used to manufacture integrated circuit components by an appropriate coating method such as a spin coater or a coater. The coating method is preferably a rotary coating using a spin coater. The rotation speed when using a spin coater for rotary coating is preferably 1000 to 3000 rpm (rotation per minute). After applying the photoresist composition, the substrate can be dried and a photoresist film can be formed. In addition, various base coating films (inorganic films, organic films, anti-reflective films) can be formed on the lower layer of the photoresist film as needed.

As a drying method, for example, a method of drying by heating can be cited. Heating can be implemented by a device equipped in a common exposure machine and/or developer, or can be implemented using a hot plate or the like. The heating temperature is preferably 80 to 150° C., more preferably 80 to 140° C., and further preferably 80 to 130° C. The heating time is preferably 30 to 1000 seconds, more preferably 60 to 800 seconds, and further preferably 60 to 600 seconds.

The thickness of the photoresist film is not particularly limited, but from the perspective of forming a fine pattern with higher precision, it is preferably 10 to 120 nm. In the case of EUV exposure and EB exposure, the thickness of the photoresist film is more preferably 10 to 65 nm, and more preferably 15 to 50 nm. In the case of ArF immersion exposure, the thickness of the photoresist film is more preferably 10 to 120 nm, and more preferably 15 to 90 nm.

In addition, a top coating composition can be used to form a top coating on the upper layer of the photoresist film. The top coating composition is preferably not mixed with the photoresist film and can be evenly coated on the upper layer of the photoresist film. The top coating is not particularly limited, and a previously known top coating can be formed by a previously known method. For example, the top coating can be formed based on the description of paragraphs [0072] to [0082] of Japanese Patent Publication No. 2014-059543. For example, it is preferred to form a top coating containing an alkaline compound as described in Japanese Patent Publication No. 2013-61648 on the photoresist film. Furthermore, the top coating is preferably a compound containing at least one group or bond selected from the group consisting of ether bonds, thioether bonds, hydroxyl groups, thiol groups, carbonyl bonds, and ester bonds.

<Process 2: Exposure process> Process 2 is a process for exposing the photoresist film. As a method of exposure, a method of irradiating the formed photoresist film through a prescribed mask can be cited. As actinic rays or radiation, infrared light, visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light, X-rays, and electron beams can be cited. Far ultraviolet light with a wavelength of less than 250nm is preferred, less than 220nm is more preferred, and particularly preferably 1 to 200nm is preferred. Specifically, KrF excimer laser (248nm), ArF excimer laser (193nm), _F2 excimer laser (157nm), EUV (13nm), X-rays, and electron beams can be cited.

After exposure, it is preferred to perform post-exposure heat treatment (also called post-exposure baking) before development. The post-exposure heat treatment can promote the reaction of the exposed part, thereby making the sensitivity and pattern shape better. The heating temperature is preferably 80 to 150°C, more preferably 80 to 140°C, and more preferably 80 to 130°C. The heating time is preferably 10 to 1000 seconds, more preferably 10 to 180 seconds, and more preferably 30 to 120 seconds. Heating can be implemented by a device equipped in a conventional exposure machine and/or developer, or by using a hot plate, etc.

<Process 3: Development process> Process 3 is a process of developing the exposed photoresist film using a developer to form a pattern. The developer can be an alkaline developer or a developer containing an organic solvent (hereinafter also referred to as an organic developer), preferably an organic developer.

As developing methods, for example, there can be cited a method of immersing a substrate in a tank filled with developer for a certain period of time (immersion method), a method of developing by accumulating developer on the substrate surface by surface tension and allowing it to stand for a certain period of time (liquid coating method), a method of spraying developer on the substrate surface (spraying method), and a method of continuously spraying developer while scanning a developer discharge nozzle at a certain speed on a substrate rotating at a certain speed (dynamic distribution method). In addition, after the development process, a process of stopping the development while replacing with another solvent can also be implemented. The development time is not particularly limited as long as it is a time for the resin in the unexposed part to be fully dissolved, and is preferably 10 to 300 seconds, and more preferably 20 to 120 seconds. The temperature of the developer is preferably 0-50°C, more preferably 15-35°C.

The alkaline developer is preferably an alkaline aqueous solution containing an alkali. The type of the alkaline aqueous solution is not particularly limited. For example, there can be cited alkaline aqueous solutions containing quaternary ammonium salts represented by tetramethylammonium hydroxide, inorganic bases, primary amines, secondary amines, tertiary amines, alcohol amines, or cyclic amines. Among them, the alkaline developer is preferably an aqueous solution of a quaternary ammonium salt represented by tetramethylammonium hydroxide (TMAH). Appropriate amounts of alcohols, surfactants, etc. can be added to the alkaline developer. The alkaline concentration of the alkaline developer is generally preferably 0.1 to 20% by mass. The pH of the alkaline developer is generally preferably 10.0 to 15.0.

The organic developer is preferably a developer containing at least one organic solvent selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents, and hydrocarbon solvents.

The above solvents may be mixed in multiple forms, or may be mixed with solvents other than the above or water. The water content of the developer as a whole is preferably less than 50% by mass, more preferably less than 20% by mass, further preferably less than 10% by mass, and particularly preferably substantially free of water. The content of the organic solvent relative to the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, further preferably 90% by mass or more and 100% by mass or less, and particularly preferably 95% by mass or more and 100% by mass or less, relative to the total amount of the developer.

<Other processes> The above-mentioned pattern forming method is preferably a process including a cleaning process with a rinse solution after process 3.

As a rinse liquid used in a rinse process after a process of developing using an alkaline developer, for example, pure water can be cited. In addition, an appropriate amount of a surfactant can be added to the pure water. An appropriate amount of a surfactant can also be added to the rinse liquid.

The rinse solution used in the rinse process after the development process using an organic developer is not particularly limited as long as it does not dissolve the pattern, and a solution containing a general organic solvent can be used. The rinse solution is preferably a rinse solution containing at least one organic solvent selected from the group consisting of hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents.

The method of the rinsing process is not particularly limited. For example, there can be cited a method of continuously spraying a rinsing liquid onto a substrate rotating at a certain speed (spin coating method), a method of immersing a substrate in a tank filled with a rinsing liquid for a certain period of time (immersion method), and a method of spraying a rinsing liquid onto the surface of a substrate (spraying method). In addition, the pattern forming method of the present invention can include a heating process (Post Bake) after the rinsing process. By this process, the developer and rinsing liquid remaining between and inside the patterns are removed by baking. In addition, by this process, the photoresist pattern is annealed and the surface roughness of the pattern is improved. The heating process after the rinsing process is usually carried out at 40-250℃ (preferably 90-200℃) for 10 seconds to 3 minutes (preferably 30 seconds to 120 seconds).

Furthermore, the formed pattern can be used as a mask to perform etching processing on the substrate. That is, the pattern formed in process 3 can be used as a mask to process the substrate (or the lower film and the substrate) to form a pattern on the substrate. The processing method of the substrate (or the lower film and the substrate) is not particularly limited, but it is preferably a method of using the pattern formed in process 3 as a mask to form a pattern on the substrate by dry etching the substrate (or the lower film and the substrate). Dry etching is preferably oxygen plasma etching.

The various materials used in the photoresist composition and the pattern forming method of the present invention (e.g., solvent, developer, rinse solution, anti-reflection film forming composition, top coating forming composition, etc.) preferably do not contain impurities such as metals. The impurity content contained in these materials is preferably 1 mass ppm (parts per million) or less, more preferably 10 mass ppb (parts per billion) or less, further preferably 100 mass ppt (parts per trillion) or less, particularly preferably 10 mass ppt or less, and most preferably 1 mass ppt or less. Here, as metal impurities, for example, Na, K, Ca, Fe, Cu, Mg, Al, Li, Cr, Ni, Sn, Ag, As, Au, Ba, Cd, Co, Pb, Ti, V, W, and Zn can be cited.

As a method for removing impurities such as metal from various materials, for example, filtering using a filter can be cited. In paragraph [0321] of International Publication No. 2020/004306, details of filtering using a filter are described.

In addition, as a method for reducing impurities such as metals contained in various materials, for example, there are a method of selecting raw materials with a low metal content as raw materials constituting various materials, a method of filtering the raw materials constituting various materials with a filter, and a method of forming an inner lining in an apparatus using Teflon (TEFLON, registered trademark) to perform distillation under conditions that suppress contamination as much as possible.

In addition to filter filtration, impurities can be removed by using adsorbent materials, or filter filtration and adsorbent materials can be used in combination. As the adsorbent material, known adsorbent materials can be used, for example, inorganic adsorbent materials such as silica gel and zeolite, and organic adsorbent materials such as activated carbon can be used. In order to reduce impurities such as metals contained in the above-mentioned materials, it is necessary to prevent the mixing of metal impurities in the manufacturing process. Whether the metal impurities have been fully removed from the manufacturing device can be confirmed by measuring the content of metal components contained in the cleaning solution used to clean the manufacturing device. The content of metal components contained in the cleaning solution after use is preferably less than 100 mass ppt, more preferably less than 10 mass ppt, and further preferably less than 1 mass ppt.

In addition, the photoresist composition sometimes contains water as an impurity. When containing water as an impurity, the content of water is preferably as small as possible, and may be 1 to 30,000 mass ppm relative to the entire photoresist composition. In addition, the photoresist composition sometimes contains residual monomers (for example, monomers derived from raw material monomers used in the synthetic resin (A)) as impurities. When containing residual monomers as impurities, the content of residual monomers is preferably as small as possible, and may be 1 to 30,000 mass ppm relative to the total solid content of the photoresist composition.

Conductive compounds can be added to organic treatment liquids such as rinse liquids to prevent electrostatic charging and subsequent electrostatic discharge, and prevent malfunctions in liquid piping and various components (filters, O-rings, tubes, etc.). There are no particular restrictions on the conductive compound, and methanol can be cited as an example. There are no particular restrictions on the amount of addition, but from the perspective of maintaining better developing characteristics or cleaning characteristics, it is preferably 10% by mass or less, and more preferably 5% by mass or less. As liquid piping, for example, SUS (stainless steel) or various piping coated with polyethylene, polypropylene, or fluororesin (polytetrafluoroethylene or perfluoroalkoxy resin, etc.) that has been treated with anti-static treatment can be used. Similarly, for filters and O-rings, polyethylene, polypropylene or fluororesins (polytetrafluoroethylene or perfluoroalkoxy resins, etc.) that have been treated with antistatic agents can also be used.

[Manufacturing method of electronic device] The present invention also relates to a manufacturing method of an electronic device including the above-mentioned pattern forming method, and an electronic device manufactured by the manufacturing method. The electronic device of the present invention can be preferably mounted on electrical and electronic equipment (home appliances, OA (Office Automation), media-related equipment, optical equipment, and communication equipment, etc.). [Example]

The present invention is described in more detail below based on the embodiments. The materials, usage amounts, ratios, processing contents, and processing steps shown in the following embodiments can be appropriately changed as long as they do not deviate from the main purpose of the present invention. Therefore, the scope of the present invention should not be limited to the embodiments shown below.

[Various components of the photosensitive or radiation-sensitive resin composition] [Resin] The resins (A-1 to A-13, and RA-1) shown in Table 1 are as follows. A-4 was synthesized using the synthesis method (Synthesis Example 1) described later. A-1 to A-3, A-5 to A-13, and RA-1 were synthesized using the synthesis method (Synthesis Example 1) of A-4 described later or a known method. Table 1 shows the content (mol% in order from left to right) of each repeating unit disclosed later, the weight average molecular weight (Mw), and the dispersion (Mw/Mn). In addition, the weight average molecular weight (Mw) and dispersion (Mw/Mn) of A-1 to A-13 and RA-1 were measured by GPC (carrier: tetrahydrofuran (THF)) (polystyrene conversion amount). In addition, the content of each repeating unit was measured by ¹³ C-NMR (Nuclear Magnetic Resonance).

[Table 1]

The structural formulas of A-1 to A-13 and RA-1 are shown below. A-1 to A-13 are equivalent to resin (A). RA-1 is not equivalent to resin (A). However, in Table 3 below, RA-1 is listed in the column of resin (A) for convenience.

[Chemical formula 19]

<Synthesis Example 1: Synthesis of Resin A-4>

[Chemical formula 20]

Under a nitrogen flow, 2.33 g of cyclohexanone was placed in a three-necked flask and heated to 85°C. Next, a mixed solution of 10.7 g of monomer M-1, 19.30 g of monomer M-2, 3.03 g of a 20 mass% cyclohexanone solution of polymerization initiator V-601 (manufactured by Fuji Film Co., Ltd. and Wako Pure Chemical Industries, Ltd.), and 7.8 g of cyclohexanone was added dropwise to the three-necked flask over 4 hours. After the addition was completed, the mixture was further reacted at 85°C for 2 hours. After the reaction was completed, the reaction solution was cooled. Next, the cooled reaction solution was added dropwise to 300 g of stirred methanol, and the powder precipitated by the addition was filtered and dried to obtain resin A-4 (12.5 g).

The composition ratio (molar ratio) of the repeating units of the above resin A-4 determined by NMR (nuclear magnetic resonance) method was: repeating units derived from monomer M-1/repeating units derived from monomer M-2 = 43/57. In addition, the weight average molecular weight of the obtained resin A-4 measured by GPC was 48,000 in terms of standard polystyrene, and the dispersion degree (Mw/Mn) was 1.8.

[Ionic compound (B)] The structural formulas of B-1 to B-6 corresponding to the ionic compound (B) are shown below. nBu in B-3 represents an n-butyl group.

[Chemical formula 21]

[Hydrophobic resin] Table 2 shows the types and contents (molar ratio) of the repeating units of the hydrophobic resins (C-1 to C-4), the weight average molecular weight (Mw), and the dispersion (Mw/Mn). In addition, the types of repeating units are shown by the types of monomers corresponding to the following repeating units.

[Table 2]

The structural formulas of the monomers (MC-1 to MC-10) corresponding to the repeating units C-1 to C-4 are shown below.

[Chemical formula 22]

[Surfactant] The surfactants used are shown below. W-1: MEGAFACE F176 (manufactured by DIC Corporation, fluorine-based) W-2: MEGAFACE R08 (manufactured by DIC Corporation, fluorine- and silicon-based)

[Solvent] The solvents used are shown below. SL-1: Propylene glycol monomethyl ether acetate (PGMEA) SL-2: Propylene glycol monomethyl ether (PGME) SL-3: Cyclohexanone SL-4: γ-butyrolactone SL-5: Ethyl lactate SL-6: Diacetone alcohol

[Developer, rinser] The developer and rinser used are shown below. D-1: Butyl acetate D-2: Isopropyl acetate D-3: Butyl acetate: n-undecane = 90:10 (mass ratio) D-4: 4-methyl-2-pentanol D-5: 2.38 mass% tetramethylammonium hydroxide aqueous solution D-6: Pure water

[Preparation of photoresist composition] Each component other than the solvent shown in Table 3 was used in the content (mass parts) shown in Table 3 and mixed with the solvent shown in Table 3. Next, the obtained mixed solution was filtered with a polyethylene filter with a pore size of 0.03μm to prepare a photoresist composition (Re-1 to Re-14, Re-X1). The solid component concentration of each photoresist composition was appropriately adjusted within the range of 1.2 to 2.3 mass % so that it could be applied according to the film thickness shown in Table 4 described later. The so-called solid component refers to all components except the solvent. The obtained photoresist composition was used in the examples and comparative examples. Table 3 shows the types of solvents used and their mass ratios. In Re-14, 40.0 parts by weight of A-4 and A-6 were used as the resin (A).

[table 3]

[Pattern formation and evaluation] 〔Pattern formation and evaluation by EUV exposure: Examples 1 to 15, Comparative Example 1〕 ＜Pattern formation＞ The composition for forming an underlayer film SHB-A940 (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to a silicon wafer and baked at 205°C for 60 seconds to form an underlayer film with a thickness of 20 nm. On the underlayer film, a photoresist film was formed under the conditions (thickness and PreBake) described in Table 4 using the photoresist composition shown in Table 4. Thus, a silicon wafer having a photoresist film was formed. PreBake is heating before exposure, and the heating temperature and heating time are described in Table 4. The silicon wafer with the photoresist film obtained by the above steps was patterned using an EUV exposure device (manufactured by Exitech, Micro Exposure Tool, NA0.3, Quadrupol, outer sigma 0.68, inner sigma 0.36). In addition, as a reticle, a mask with a line size of 16nm and a line: space ratio of 1:1 was used. Then, only if there is a record, after baking (Post Exposure Bake: PEB) under the conditions shown in Table 4 below, the developer shown in Table 4 below is stirred for 30 seconds for development, and only if there is a record, the rinse solution shown in Table 4 below is poured for 10 seconds while rotating the wafer at a speed of 1000 rpm for rinsing, and then the wafer is rotated at a speed of 4000 rpm for 30 seconds, thereby obtaining a line and space pattern with a line size (width) of 16nm and line: space = 1:1.

<Evaluation> [Evaluation of sensitivity (mJ/cm ² )] Using a scanning electron microscope (SEM (Hitachi, Ltd. S-9380II)), the line width of the line and space pattern was measured while changing the exposure amount, and the exposure amount when the line size (width) was 16nm was obtained and used as the sensitivity (mJ/cm ² ). The results are shown in Table 4. In addition, this evaluation was performed by controlling the interval from the end of exposure to the start of development processing to 3 minutes.

[Evaluation of LWR (nm) performance] The pattern obtained in the above <Pattern formation> was observed from above the pattern using a length-measuring scanning electron microscope (SEM (Co., Ltd.) Hitachi, Ltd. S-9380II)). The line width of the pattern was observed at 250 locations, and its standard deviation (σ) was calculated. The measured deviation of the line width was evaluated with 3σ, and the value of 3σ was set as LWR (nm). The results are shown in Table 4. The smaller the LWR value, the better the LWR performance. The LWR evaluation is preferably 4.0 or less, more preferably 3.6 or less, further preferably 3.3 or less, particularly preferably 3.1 or less, and the best is 2.9 or less.

[Table 4]

It is clear from the results in Table 4 that the photoresist composition of the embodiment has excellent sensitivity and the LWR performance of the formed pattern is excellent.

[Pattern formation and evaluation by EB exposure: Examples 1A to 15A] Similar to Examples 1 to 15, each photoresist composition was used to form a photoresist film, perform pattern formation, and perform evaluation, except that an electron beam (EB) was used instead of EUV as the exposure light source. As a result, even when EB exposure was used, the same trend results as when EUV exposure was used for pattern formation were obtained. [Industrial applicability]

According to the present invention, a photosensitive or radiation-sensitive resin composition capable of forming a pattern with excellent sensitivity and excellent LWR performance can be provided. In addition, according to the present invention, a photoresist film formed using the above-mentioned photosensitive or radiation-sensitive resin composition, a pattern forming method using the above-mentioned photosensitive or radiation-sensitive resin composition, and a method for manufacturing an electronic device can be provided.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on the Japanese patent application (Japanese Patent Application No. 2022-128923) filed on August 12, 2022, the contents of which are incorporated herein by reference.

without

Claims (8)

A resin composition having photosensitive or radiation-sensitive properties, the resin composition comprising a resin (A), wherein the resin (A) comprises a repeating unit represented by the following formula (a1) and at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (a2) and a repeating unit represented by the following formula (a3), [Chemical Formula 1] In formula (a1), ^X1 represents a halogen atom, ^W1 represents an aromatic group, ^R1 represents a hydrogen atom or a substituent, and ^R1 and ^W1 are bonded to form a ring. In formula (a2), ^X2 represents an alkyl group, ^W2 represents an aromatic group, ^R2 represents a hydrogen atom or a substituent, and ^R2 is bonded to ^X2 or ^W2 to form a ring. In formula (a3), ^X3 represents a halogen atom, a cyano group, ^-COORA1 , _-OCORA2 , ^-SO2RA3 or an alkyl group, ^RA1 , ^RA2 and ^RA3 each independently represent an organic group, ^R3 represents a hydrogen atom or a substituent, ^L1 represents a linking ^group , ^W3 represents an organic group, and ^R3 is bonded to ^X3 or ^R3 to form a ring. The resin composition as described in claim 1 further contains an ionic compound (B), and the resin (A) has an interactive group that interacts with the ionic compound (B). The resin composition as described in claim 2, wherein the interactive group is a phenolic hydroxyl group or a carboxyl group. The resin composition as described in any one of claims 1 to 3, wherein ^L1 in the formula (a3) represents -O-. The resin composition as described in any one of claims 1 to 3, wherein ^W3 in the formula (a3) represents an alkyl group, a cycloalkyl group or an aryl group. A photoresist film is formed using the resin composition described in any one of claims 1 to 5. A pattern forming method comprises: a process of forming a photoresist film using the resin composition described in any one of claims 1 to 5; a process of exposing the film; and a process of developing the exposed film using a developer. A method for manufacturing an electronic device, comprising the pattern forming method described in claim 7.