Photoacid generator, resist composition and applications thereof

Abstract

The invention relates to a photoacid generator, a resist composition and a pattern forming method. The present invention provides a resist composition having high sensitivity and low LWR in both a positive resist material and a negative resist material, and a pattern forming method using the same. The resist composition includes a film-forming resin and an acid generator including a sulfonate compound represented by formula (1). # imgabs0 #

Description

Technical Field

[0001] The invention relates to a photoacid generator, an anti-corrosion agent composition and applications thereof. Background Art

[0002] With the high integration and high speed of large-scale integrated circuits (LSI), the miniaturization of lithography patterns is also advancing rapidly. In particular, the expansion of the flash memory market and the increase in storage capacity are driving this trend. As a cutting-edge miniaturization pattern technology, 45nm node devices are being mass-produced using immersion ArF lithography. More advanced extreme ultraviolet (EUV) lithography and double patterning immersion ArF lithography have pushed the technology node to 7nm or even 3nm.

[0003] With the development of miniaturization, the contrast of light decreases when approaching the diffraction limit of light, resulting in reduced resolution of hole patterns and groove patterns, while showing poor exposure latitude (EL). In addition, as the thickness of the resist film becomes thinner, the edge roughness (LWR) tends to increase. The edge roughness (LWR) of the line pattern and the dimension uniformity (CDU) of the hole pattern are also issues worthy of attention. The uneven distribution of film-forming resins and acid generators, the aggregation of resins or acid generators, and the diffusion of acid in post-baking have a direct impact on LWR and CDU.

[0004] In the immersion ArF photoresist composition, high sensitivity, high resolution and low LWR need to be achieved simultaneously. Shortening the acid diffusion distance will reduce the LWR, but will reduce the sensitivity. Lowering the post-exposure bake (PEB) temperature will reduce the LWR, but will also reduce the sensitivity. Increasing the amount of quencher added will reduce the LWR, but the sensitivity will still be reduced to a certain extent. In order to break the contradictory relationship between the sensitivity and LWR of the photoresist, the present invention provides an onium salt compound with a new structure as a photoacid generator to achieve the effects of high sensitivity, high resolution and low LWR. Summary of the invention

[0005] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0006] Another object of the present invention is to provide a photoacid generator required for use in a high-sensitivity, low-LWR photoresist, a positive or negative resist composition, and a pattern forming method using the photoresist.

[0007] As a result of intensive studies to achieve the above object, the present inventors have found that using a sulfonium salt or iodonium salt of sulfonic acid containing salicylic acid and benzolactone formed therefrom as a photoacid generator can reduce LWR and improve resolution and sensitivity.

[0008] In order to achieve these objects and other advantages according to the present invention, a photoacid generator is provided, comprising a compound represented by the following formula (1):

[0009]

[0010] In formula (1), R 1 represents a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms;

[0011] R 2 represents a divalent hydrocarbon group having 1 to 20 carbon atoms which may be substituted with a heteroatom or may contain a lactone structure;

[0012] R 3 represents a divalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a heteroatom or which contains a lactone structure;

[0013] L 1 , L 2 represents a single bond, -CO-O-, -O-CO-, -O-CO-O-, or -O-;

[0014] R 4 , R 5 , R 6 represents a hydrogen atom, a substituted or unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms;

[0015] R 1 , Rf 2 each independently represents a hydrogen atom, a fluorine atom or a trifluoromethyl group;

[0016] Y represents a hydrogen atom or an alkyl group of 1 to 3 carbon atoms;

[0017] n is 0 or 1, m, r and p are 1 or 2, and s is an integer from 0 to 2;

[0018] M + is a sulfonium cation represented by the following formula (2) or an iodonium cation represented by the following formula (3);

[0019]

[0020] In formula (2) and formula (3), R 7 -R 11 Each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, R 7 , R 8 and R 9 May bond to each other to form a ring with the sulfur atom to which they are bonded.

[0021] Preferably, R 5 and R 6represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms.

[0022] Preferably, L 1 is -CO-O-, m is 1, Rf 1 and Rf 2 It is a fluorine atom.

[0023] Preferably, n is 1, R 2 It is a polycyclic alkane structure containing sultone.

[0024] The invention provides a resist composition, comprising a photoacid generator.

[0025] Preferably, the copolymer comprises a repeating unit selected from the group consisting of the following formula (4), formula (5) and formula (6):

[0026]

[0027] In formula (4) to formula (6), R 12 Each is independently a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group;

[0028] In formula (4), R 13 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a substituent;

[0029] In formula (5), R 14 is hydrogen or alkyl, R 15 is hydrogen, alkyl, alkoxy, acyl or acyloxy, R 15 Some or all of the hydrogen atoms may be substituted, and b is an integer from 1 to 3;

[0030] In formula (6), c is an integer of 1 to 3.

[0031] Specifically, it also includes a polymer of repeating units represented by formula (5) and formula (7), and the repeating unit represented by formula (7) is as follows:

[0032]

[0033] In formula (7), R 12 is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and l, k and t are each independently an integer of 1-5.

[0034] Specifically, with respect to 100 mol % of the copolymer, the structure represented by formula (4) accounts for 30 to 70 mol %, the structure represented by formula (5) accounts for 10 to 50 mol %, and the structure represented by formula (6) accounts for 1 to 10 mol %.

[0035] Specifically, the polymer of the repeating units represented by formula (5) and formula (7) accounts for 1 to 5 wt % of the polymer of the repeating units represented by formula (4), formula (5) and formula (6).

[0036] The present invention provides a method for forming a resist pattern, comprising the steps of forming a resist film on a substrate using the resist composition, exposing the resist film to high-energy radiation, and developing the resist film to obtain a pattern.

[0037] The present invention has at least the following beneficial effects:

[0038] The onium salt compound of the present invention is a sulfonium salt or iodonium salt of sulfonic acid with salicylic acid and benzolactone formed therefrom, and when used as a photoacid generator of an immersion ArF photoresist composition, it can effectively improve sensitivity and resolution. In addition, the acid diffusion length can be appropriately controlled, and low LWR and large DOF (depth of focus) can be achieved at the same time, and high sensitivity and high resolution can be achieved at the same time.

[0039] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0040] The first aspect of the present invention provides a photoacid generator, comprising a compound represented by the following formula (1):

[0041]

[0042] In formula (1), R 1 represents a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms;

[0043] R 2 represents a single bond, a divalent hydrocarbon group having 1 to 20 carbon atoms which is substituted or unsubstituted with a heteroatom or contains a lactone structure;

[0044] R 3 represents a divalent hydrocarbon group having 1 to 10 carbon atoms which is substituted or unsubstituted with a heteroatom or contains a lactone structure;

[0045] L 1 , L 2 represents a single bond, -CO-O-, -O-CO-, -O-CO-O-, or -O-;

[0046] R 4 , R 5 , R 6 represents a hydrogen atom, a substituted or unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms;

[0047] R 1 , Rf2 each independently represents a hydrogen atom, a fluorine atom or a trifluoromethyl group;

[0048] Y represents a hydrogen atom or an alkyl group of 1 to 3 carbon atoms. When Y is a hydrogen atom, it represents two hydrogen atoms connected to the oxygen and phenyl groups on the ester bond respectively;

[0049] n is 0 or 1, m, r and p are 1 or 2, and s is an integer from 0 to 2;

[0050] M + is a sulfonium cation represented by the following formula (2) or an iodonium cation represented by the following formula (3);

[0051]

[0052] In formula (2) and formula (3), R 7 -R 11 Each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, R 7 , R 8 and R 9 May bond to each other to form a ring with the sulfur atom to which they are bonded.

[0053] R 1 represents a divalent hydrocarbon group having a single bond or having 1 to 20 carbon atoms. Aliphatic hydrocarbons may be linear, branched or cyclic, and specifically include alkane groups such as methane, ethane, propane, butane, 2-methylpropane, and cyclohexane; and groups such as ethylene, propylene, 1-butene, 2-butene, 2-methylpropylene, and cyclohexene. Examples of aromatic hydrocarbon groups include benzene, naphthalene, toluene, xylene, anthracene, and the like. Among them, R 1 A single bond or a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms is preferred.

[0054] R 2The divalent hydrocarbon group may be linear, branched or cyclic, and specific examples thereof include methylene, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-1,1-diyl, propane-2,2-diyl, 2-methylpropane-1,1-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1, The invention also includes divalent aliphatic hydrocarbon groups such as saturated cyclic divalent hydrocarbon groups such as cyclopentanediyl, cyclohexanediyl, norbornanediyl and adamantanediyl; divalent aromatic groups such as arylene hydrocarbon groups such as phenylene and naphthylene. In addition, some hydrogen atoms in these groups may be substituted by alkyl groups such as methyl, ethyl, propyl, n-butyl and tert-butyl. In addition, some hydrogen atoms in these groups may be substituted by heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., as well as oxygen atoms, sulfur atoms, etc. Heteroatom-containing groups such as atoms, nitrogen atoms, etc. may be introduced to generate hydroxyl, cyano, carbonyl, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, which may include sultone ring, carboxylic anhydride (-C(=O)-OC(=O)-), halogenated alkyl, etc. As the above heteroatoms, sulfur atoms and oxygen atoms are preferred. 2 Preferred is a single bond, a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, or a group having a sultone ring.

[0055] R 3 represents a divalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted with or without heteroatoms or contain a lactone structure. Aliphatic hydrocarbons may be linear, branched or cyclic, and specifically, examples include alkanes such as methane, ethane, propane, butane, 2-methylpropane, and cyclohexane; ethylene, propylene, 1-butene, 2-butene, 2-methylpropylene, and cyclohexene. Examples of aromatic hydrocarbons include benzene, naphthalene, toluene, xylene, anthracene, and the like. Where R 3 Preferred is a single bond, a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, or a group having a sultone ring.

[0056] R 4 , R 5 , R 6represents a hydrogen atom, a substituted or unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms; the alkyl group may be linear, branched or cyclic, and specifically, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, tert-pentyl, cyclohexyl, etc. may be mentioned; vinyl, propenyl, 1-butenyl, 2-butenyl, 2-methylpropenyl, cyclohexenyl, etc. The alkoxy group may be linear, branched or cyclic, and specific examples thereof include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, butoxy, n-pentoxy, sec-pentoxy, tert-pentoxy, neopentoxy, n-hexoxy, n-heptoxy, n-octoxy, 2-ethylhexyloxy, n-nonyloxy, n-decyloxy group, vinyloxycarbonyl, 1-propenyloxy, 2-propenyloxy, etc.

[0057] The compound represented by formula (1) is an onium salt compound of sulfonic acid. When used as a photoacid generator in a resist composition, the acidity of the sulfonic acid generated by exposure can be arbitrarily selected. The photoacid generator refers to a compound that generates an acid in response to laser radiation.

[0058] The anion part of the photoacid generator of the present invention can be specifically listed as follows:

[0059]

[0060] The anion part of the photoacid generator of the present invention can be specifically listed as follows:

[0061]

[0062] When the unit containing an acid-labile group of the film-forming resin used in the resist composition of the present invention is composed of a tertiary ester, in order to satisfy the acidity suitable for high sensitivity, it is preferred that the sulfonic acid generated from the onium salt compound has a structure in which the α position is fluorinated (i.e., in formula (1), m is 1, Rf 1 and Rf 2 are all fluorine atoms), as shown in formula (1a).

[0063]

[0064] The method for producing the onium salt compound of the present invention will be described in detail using the sulfonate anion represented by the above formula (1a) as an example, but the present invention is not limited to this synthesis method.

[0065]

[0066] The first step is to use a benzene ring with X 1 Substituent containing salicylic acid and benzolactone formed therefrom (hereinafter referred to as compound S) as raw materials, wherein X 1It is a chlorine atom, a bromine atom or an iodine atom, preferably a chlorine atom. The phenolic hydroxyl groups of compound S are all methoxymethylated (hereinafter referred to as MOM), which plays a role in protecting the phenolic hydroxyl groups. The reaction can be carried out under known conditions. For example, methoxymethyl chloride (MOMCl) and an organic base (amine) are preferably used as reactants to form MOM. As an organic base, N, N-diisopropylethylamine (DIPEA) is preferably used. The reaction is carried out in a solvent-free or solvent such as dichloromethane, acetonitrile, ether, tetrahydrofuran, N, N-dimethylformamide, toluene, hexane, etc. Compound S, MOMCl, and DIPEA are added sequentially or simultaneously, and cooled or heated if necessary. The amount of MOMCl used varies according to the conditions, for example, 1 mol of each phenolic hydroxyl group or carboxyl group of compound S as a raw material, preferably 1 to 5 mol, more preferably 1 to 2 mol. The amount of base used varies according to the conditions, for example, 1 mol to 5 mol, more preferably 1 to 2 mol, relative to 1 mol of MOMCl used. The reaction time is preferably about 0.5 to 24 h, but from the viewpoint of yield, it is preferably reacted by gas chromatography (GC) or silica gel thin layer chromatography (TLC) to terminate the reaction. The compound (hereinafter referred to as compound P) in which all phenolic hydroxyl groups are protected by MOM can be obtained from the organic phase after ordinary water washing, and if necessary, it can be purified by conventional methods such as chromatography, distillation and recrystallization. Or, in some cases, the reaction solution can be directly purified without washing aftertreatment after filtering out the salt produced in the reaction.

[0067] The second step is to prepare compound P into an organozinc reagent by magnesium / zinc chloride and to couple it with a compound containing R 3 and may contain R 2 The carboxylic acid ester (hereinafter referred to as compound I) is subjected to Negishi reaction. 2 is a chlorine atom, a bromine atom or an iodine atom, preferably a chlorine atom. 1 The carbon atoms connected to X 2The connected carbon atoms are directly coupled, which is a carbon chain growth reaction. The reaction can be carried out under known conditions, for example, at low temperature, compound P is dissolved in a solvent, magnesium powder and zinc chloride powder are added, the compound is prepared as an organic zinc reagent, and compound I is added under a suitable catalyst. The reaction is carried out in an ether solvent such as tetrahydrofuran, ether, and dioxane. The reaction temperature is between -70°C and 50°C, preferably -70°C to 30°C, and more preferably -70°C to 0°C. The catalyst is an organic palladium catalyst, preferably an organic palladium with a valence of 0 or +2. Relative to 1 mol of compound P, the amount of magnesium powder added is 1-2 mol, preferably 1-1.5 mol, the amount of zinc chloride added is 1-2 mol, preferably 1-1.5 mol, the amount of catalyst added is 0.001-1 mol, preferably 0.01-0.1 mol, and the amount of compound I added is 0.5-2 mol, preferably 0.5-1.5 mol. The reaction time is preferably about 0.5 to 24 hours, but from the viewpoint of yield, it is preferred to react by gas chromatography (GC) or silica gel thin layer chromatography (TLC) to terminate the reaction. The coupling product of compound P and compound I (hereinafter referred to as compound J) can be obtained from the organic phase after ordinary water washing, and if necessary, it can be purified by conventional methods such as chromatography and recrystallization. Alternatively, in some cases, the reaction solution can be purified directly without water washing after filtering out the salt produced in the reaction.

[0068] The third step is to hydrolyze the carboxylic acid ethyl ester of compound J with a strong base to deprotect the carboxyl group. The reaction can be carried out in a solvent-free or solvent such as methanol, ethanol, tetrahydrofuran, acetonitrile, N, N-dimethylformamide, etc. by sequentially or simultaneously adding compound P and 1mol / L sodium hydroxide or potassium and other alkaline aqueous solutions for hydroxide. It is preferably carried out by cooling or heating according to the situation. The amount of alkali used is preferably 1 to 10mol, more preferably 1 to 5mol relative to 1mol of carboxylic acid ethyl ester. The reaction time is preferably about 0.5 to 24h, but from the viewpoint of yield, it is preferably reacted by gas chromatography (GC) or silica gel thin layer chromatography (TLC) to terminate the reaction. In order to quench the reaction, it is preferably neutralized with a weakly acidic aqueous solution of ammonium chloride, but the present invention is not limited thereto. The carboxylic acid compound (hereinafter referred to as compound K) can be obtained by ordinary water washing post-treatment, and if necessary, it can be purified by conventional methods such as distillation, chromatography and recrystallization. Alternatively, in some cases, the reaction solution can be directly purified without aqueous post-treatment after filtering out the salt produced in the reaction.

[0069] In the fourth step, the compound K obtained in the second step is condensed with the sulfonic acid compound S and the alcohol to carry out an esterification reaction, and then the MOM group is deprotected by acid treatment to obtain a sulfonate. The step of obtaining the compound (hereinafter referred to as compound O). The condensation reaction can be carried out under known conditions, and specifically various condensing agents can be used. The condensing agents used include N, N'-dicyclohexylcarbodiimide, N, N'-diisopropylcarbodiimide, 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, etc., but from the viewpoint of easy removal of the urea compound generated as a by-product after the reaction, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride is preferably used. The reaction is preferably carried out by sequentially or simultaneously adding a carboxylic acid, an alcohol of an alkanesulfonic acid and a condensing agent in a halogenated solvent such as dichloromethane, according to the reaction conditions. It is necessary to cool or heat to carry out. Adding 4-dimethylaminopyridine as a reaction catalyst can increase the reaction rate. The reaction time is preferably about 12 to 24h, although it is preferred to track the reaction by TLC etc. to complete the reaction in terms of yield. After stopping the reaction, compound O can be obtained by washing the reaction solution with water aftertreatment. If necessary, the obtained compound J can be purified by conventional methods such as chromatography and recrystallization. In addition, in the above-mentioned synthesis scheme, the counter cation represented by Q+ is preferably an ammonium cation, specifically benzyltrimethylammonium, benzyltriethylammonium, tetrabutylammonium, triethylammonium, tributylammonium, trioctylammonium, pyridinium ammonium, ruthenium ammonium, 4-dimethylaminopyridinium ammonium, ammonium aniline, etc.

[0070] The fifth step is a step of synthesizing the onium salt compound of the present invention by exchanging the compound O obtained in the fourth step with a sulfonium salt or an iodonium salt. - Chloride ion, bromide ion, methylsulfate anion and the like are preferred as anions. The salt exchange reaction can be easily carried out by known methods, such as using a solvent to dissolve the compound and using water to extract the more water-soluble ion pair to complete the reaction. The onium salt compound can be obtained from the organic phase by conventional water washing. If necessary, conventional methods such as chromatography and recrystallization can be used for purification.

[0071] A second aspect of the present invention provides a resist composition, comprising:

[0072] (A) a photoacid generator of an onium salt compound represented by formula (1);

[0073] (B) film-forming resin;

[0074] (C) an organic solvent;

[0075] (D) Acid diffusion inhibitors;

[0076] (E) organic acid;

[0077] (F) Fluorine-containing resin.

[0078] The components in the resist composition are described in detail below.

[0079] [(A) Photoacid generator]

[0080] The photoacid generator of the onium salt compound represented by formula (1) is specifically described above. The photoacid generator is 0.1 to 40 parts by mass, preferably 1 to 30 parts by mass, and more preferably 5 to 25 parts by mass relative to 100 parts by mass of the film-forming resin (B). The amount of component (A) added within the above range can fully exert its function without reducing sensitivity or causing performance degradation due to the generation of foreign matter due to insufficient solubility. The photoacid generator can be used alone or in combination of two or more.

[0081] [(B) Film-forming resin]

[0082] The film-forming resin comprises repeating unit (4), repeating unit (5), and repeating unit (6);

[0083] The repeating unit (4) is a repeating unit of a group having a lactone structure, as shown below:

[0084]

[0085] In the above formula (4), R 12 is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group. 13 It is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a substituent.

[0086] As the above R 13 Examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-methylpropyl, 1-methylpropyl, tert-butyl, etc. In addition, examples of specific substituents that replace a part or all of the hydrogen atoms of the alkyl group include halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms, phenyl groups, acyloxy groups, and alkoxy groups.

[0087] Specific examples of the monomer providing the repeating unit (4) include 1-cyclopentyl (meth)acrylate, 1-ethyl-1-cyclopentyl (meth)acrylate, 1-isopropyl-1-cyclopentyl (meth)acrylate, 1-isopropyl-1-cyclohexyl (meth)acrylate, 1-tert-butyl-1-cyclohexyl (meth)acrylate, 1-methyl-1-cycloheptyl (meth)acrylate, 1-ethyl-1-cycloheptyl (meth)acrylate, 1-isopropyl-1-cycloheptyl (meth)acrylate, and 1-tert-butyl-1-cycloheptyl (meth)acrylate.

[0088] Among these monomers, 1-isopropyl-1-cyclopentyl(meth)acrylate and 1-ethyl-1-cyclopentyl(meth)acrylate are preferred.

[0089] The repeating unit (5) is a repeating unit having a cycloalkane, and is specifically as follows;

[0090]

[0091] In the above formula (5), R 14 R is hydrogen or alkyl. 15 R is hydrogen, alkyl, alkoxy, acyl or acyloxy. 15 A part or all of the hydrogen atoms in may be substituted. b is 1, 2 or 3.

[0092] As the above R 12 The lower alkyl group represented by is preferably an alkyl group having 1 to 4 carbon atoms, and examples thereof include methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, and 2-(2-methylpropyl).

[0093] As the above R 14 and R 15 Examples of the alkyl group include methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, 2-(2-methylpropyl), 1-pentyl, 2-pentyl, 3-pentyl, 1-(2-methylbutyl), 1-(3-methylbutyl), 2-(2-methylbutyl), 2-(3-methylbutyl), neopentyl, 1-hexyl, 2-hexyl, 3-hexyl, 1-(2-methylpentyl), 1-(3-methylpentyl), 1-(4-methylpentyl), 2-(2-methylpentyl), 2-(3-methylpentyl) , 2-(4-methylpentyl), 3-(2-methylpentyl), 3-(3-methylpentyl) and other straight-chain or linear alkyl groups having 1 to 10 carbon atoms; cyclopentyl, cyclopentylmethyl, 1-(1-cyclopentylethyl), 1-(2-cyclopentylethyl), cyclohexyl, cyclohexylmethyl, 1-(1-cyclohexylethyl), 1-(2-cyclohexylethyl), cycloheptyl, cycloheptylmethyl, 1-(1-cycloheptylethyl), 1-(2-cycloheptylethyl), 2-norbornyl and other cyclic alkyl groups having 4 to 20 carbon atoms.

[0094] As R 14 , preferably a linear or branched alkyl group having 1 to 4 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group, and further preferably a methyl group and an ethyl group. 15 , preferably methyl and ethyl, further preferably methyl.

[0095] When the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a straight chain or branched hydrocarbon group having 1 to 10 carbon atoms, it is derived from hydroxyethyl ester of acrylic acid. A repeating unit represented by the following formula (6);

[0096]

[0097] c is an integer of 1 to 3, and c is preferably 1 or 2, and more preferably 1. When c is 2, the hydroxyl group is preferably bonded to the 3- and 5-positions of the adamantyl group. When c is 1, the hydroxyl group is preferably bonded to the 3-position of the adamantyl group. c is preferably 1, and it is particularly preferred that a hydroxyl group is bonded to the 3-position of the adamantyl group.

[0098] With respect to 100 mol % of the copolymer, the structure represented by formula (4) accounts for 30 to 70 mol %, the structure represented by formula (5) accounts for 10 to 50 mol %, and the structure represented by formula (6) accounts for 1 to 10 mol %.

[0099] [(C) Organic solvent]

[0100] Examples of the organic solvent used for component (C) include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-amyl ketone, diacetone alcohol; 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether; PGMEA, propylene glycol monoethyl ether Acetic acid ester, methyl lactate, ethyl lactate, n-butyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol mono-tert-butyl ether and other esters such as acetate, methyl 2-hydroxyisobutyrate, isopropyl 2-hydroxyisobutyrate, isobutyl 2-hydroxyisobutyrate, n-butyl 2-hydroxyisobutyrate; lactones such as γ-butyrolactone (GBL); and mixed solvents thereof. The organic solvent may be used alone or in combination of two or more.

[0101] In the resist composition of the present invention, the content of the organic solvent as the component (C) is preferably 50 to 10,000 parts by mass, more preferably 100 to 5,000 parts by mass, based on 80 parts by mass of the base polymer (B).

[0102] [(D) Acid diffusion inhibitor]

[0103] Examples of the acid diffusion inhibitor include the following nitrogen-containing compounds: The radiation-sensitive resin composition can improve the goodness of the pattern shape and dimensional stability as a resist by containing the acid diffusion inhibitor.

[0104] Examples of the nitrogen-containing compound include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; dialkylamines such as di-n-butylamine, di-n-pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, and di-n-decylamine; trialkylamines such as triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, and tri-n-decylamine; and aromatic amines such as aniline, N-methylaniline, N,N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, 1-naphthylamine, 2-(4-aminophenyl)-2-(3-hydroxyphenyl)propane, and 2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane.

[0105] As the acid diffusion inhibitor, for example, there can be mentioned a compound represented by the following formula:

[0106] R 16 -CO - 2 M + (8)

[0107] R 16 The monovalent hydrocarbon groups represented by include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, t-butyl, t-pentyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norcanyl, adamantyl, phenyl, naphthyl, anthracenyl, etc. Some of the hydrogen atoms in these groups may be substituted with groups containing oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., or groups containing oxygen atoms, sulfur atoms, nitrogen atoms, etc. may be inserted between carbon-carbon atoms of these groups, or hydroxyl groups, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydrides, halogenated alkyl groups, etc. Fluorinated alkyl groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl may also be included.

[0108] The specific structures that can be listed are as follows:

[0109]

[0110] M + is a sulfonium cation represented by the following formula (2);

[0111]

[0112] In formula (2), R 7 -R 9 Each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, R7 , R 8 and R 9 May bond to each other to form a ring with the sulfur atom to which they are bonded.

[0113] M + Specifically, the structures are as mentioned above.

[0114] The content of the acid diffusion inhibitor is preferably 10 parts by mass or less relative to 100 parts by mass of the film-forming resin [B]. If the content of the acid diffusion inhibitor exceeds the upper limit, the sensitivity of the formed resist film tends to be significantly reduced.

[0115] [(E) Organic acid]

[0116] The resist composition of the present invention prevents sensitivity degradation due to blending with component (D), and also has properties such as defect reduction, resist pattern shape, and stability of the resist pattern over time. For the purpose of improvement, it is necessary to add a dibasic acid as an organic acid.

[0117] Suitable dibasic acids include, for example, malonic acid, maleic acid, succinic acid, and salicylic acid.

[0118] The amount of component (E) used is preferably 0.01 to 5.0 parts by mass, more preferably 0.1 to 3.0 parts by mass, and most preferably 0.5 to 2.5 parts by mass relative to 1 part by mass of component (D). Within the above range, the temporal stability of the resist pattern can be improved and development defects can be reduced.

[0119] [(F) Fluorine-containing resin]

[0120] In the composition of the present invention, a fluorine-added resin is added to impart water resistance to the resist film, and the resin structure is a polymer of repeating units represented by formula (5) and formula (7). The repeating unit represented by formula (7) is as shown below.

[0121]

[0122] In formula (7), R 12 is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and l, k and t are each independently an integer of 1-5.

[0123] The polymer of repeating units represented by formula (5) and formula (7) accounts for 1 to 5 wt % of the polymer of repeating units represented by formula (4), formula (5) and formula (6) based on 100 parts by mass of the film-forming resin [B].

[0124] The third aspect of the present invention provides a pattern forming method, which comprises the following steps: forming a resist film on a substrate using a resist composition, exposing the resist film to high-energy rays, and exposing the exposed resist film using a developer. It includes a developing step and obtains a pattern. More steps can be added as needed.

[0125] For example, the resist composition of the present invention can be used as a 2 , SiN, SiON, TiN, WSi, BPSG, SOG, silicon-containing anti-reflective coatings or organic hydrocarbon coatings) or substrates for mask circuit manufacturing (Cr, CrO, CrON, MoSi 2 , silicon dioxide, etc.) by spin coating, roller coating, flow coating, dip coating, spray coating, scraping coating and other appropriate coating methods to make the coating thickness 0.01 to 2 μm. It is pre-baked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes.

[0126] Then, the resist film is exposed using high-energy rays. Examples of high-energy rays include ultraviolet rays, deep ultraviolet rays, EB, X-rays, excimer lasers, gamma rays, synchrotron radiation, EUV, soft X-rays, etc. When ultraviolet rays, deep ultraviolet rays, X-rays, excimer lasers, gamma rays, synchrotron radiation, EUV, and soft X-rays are used as high-energy rays, a mask is used to form a desired pattern, and the exposure dose is preferably 1 to 200 mJ / cm 2 , more preferably 10 to 100 mJ / cm 2 When EB is used as a high energy beam, the exposure dose is preferably 0.1 to 100 μC / cm 2 , more preferably 0.5 to 50 μC / cm 2 The desired pattern is formed directly or using a mask. The resist composition of the present invention is particularly suitable for fine patterning using high energy KrF excimer laser, ArF excimer laser, EB, EUV, soft X-ray, X-ray, gamma ray, synchrotron radiation, and the like.

[0127] In addition to the usual exposure method, exposure can also be performed by an immersion method in which a liquid such as water having a refractive index of 1.0 or more is sandwiched between the resist film and the projection lens.

[0128] After the exposure, PEB may be performed on a hot plate at preferably 60 to 150° C. for 10 seconds to 30 minutes, more preferably 80 to 120° C. for 30 seconds to 20 minutes.

[0129] After exposure or PEB, development is performed. For development, for example, 0.1 to 10% by mass, preferably 2 to 5% by mass, of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH) or tetrabutylammonium hydroxide (TBAH) is used, preferably for 3 seconds to 3 minutes, more preferably for 5 seconds to 2 minutes, by dipping, immersion, spraying, etc. According to this method of development, the light-irradiated part is dissolved in the developer, and the unexposed part is dissolved in the developer, and the desired positive pattern is formed on the substrate.

[0130] Using the resist composition of the present invention, negative development can also be performed by organic solvent development to obtain a negative pattern. The developer used at this time is 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butylacetic acid, isobutyl acetate, amyl acetate, butyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, Methyl propionate, ethyl propionate, 3-ethylethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, ethyl 2-phenylacetate, etc. These organic solvents can be used alone or in combination of two or more.

[0131] Furthermore, after the development step, it may be rinsed with water, preferably for 3 seconds to 3 minutes, more preferably for 5 seconds to 2 minutes, by a conventional method such as dipping method, immersion method or spray method.

[0132] The developed hole pattern and groove pattern can also be shrunk by heat flow, RELACS technology, DSA technology, etc. A shrinking agent is applied on the hole pattern. During the baking process, the shrinking agent is cross-linked on the photoresist surface due to the diffusion of the acid catalyst from the photoresist layer, and the shrinking agent adheres to the side wall of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is 10 to 300 seconds. Finally, the excess shrinking agent is removed to shrink the hole pattern. The present invention is further described in detail below in conjunction with the embodiments so that those skilled in the art can implement it according to the text of the specification.

[0133] The present invention will be specifically described below with reference to synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples.

[0134] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0135] [Synthesis Example 1] Synthesis of sulfonium salt (PAG-1)

[0136]

[0137] 81.1 g of chloromethyl methyl ether was added dropwise to a mixed solution of 100 g of chlorosalicylic acid lactone compound S1-1, 136.7 g of diisopropylethylamine and 200 g of dichloromethane under ice bath cooling. After stirring at 40 ° C for 2 days, the reaction solution was cooled to 0 ° C and 400 g of pure water was added to quench the reaction. Then 150 g of dichloromethane was added and stirred, and the organic layer was separated. The obtained organic layer was washed with 150 g of pure water, 150 g of dilute hydrochloric acid, 150 g of pure water, 150 g of 5% sodium bicarbonate aqueous solution, and 150 g of pure water in turn. The organic layer was evaporated under reduced pressure to obtain 120.7 g of a yellow oil. The yield was 98.8%. The obtained oil P1 was directly used in the next step reaction without further purification.

[0138] The oily substance P1 was dissolved in 400g of tetrahydrofuran, and 18.1g of magnesium powder and 101.7g of anhydrous zinc chloride were added at 0°C. After stirring at 40°C for one day, the reaction temperature was lowered to -20°C, 17.5g of ditriphenylphosphine palladium dichloride was added, 61g of ethyl 2-chloroacetate (S2) was added dropwise, and the mixture was stirred at room temperature for 12h. Cold water was added to quench the reaction. Then 300g of dichloromethane was added and stirred, and the organic layer was separated. The obtained organic layer was washed with 150g of pure water, 150g of dilute hydrochloric acid, 150g of pure water, 150g of 5.0 mass% sodium bicarbonate aqueous solution, and 150g of pure water in sequence. The obtained organic layer was evaporated under reduced pressure to obtain 138.2g of yellow oily substance P2-1. 150g of THF and 50g of pure water were added to the obtained P2-1 and stirred, and 100g of 25% sodium hydroxide aqueous solution was added dropwise, and stirred at 40°C overnight. After that, the reaction solution was cooled with ice, and 250 g of 10% by mass ammonium chloride aqueous solution was added dropwise to stop the reaction. After adding 200 g of ethyl acetate and stirring, the organic layer was separated. After washing the organic layer with 100 g of 5% by mass salt water and 100 g of pure water, the obtained organic layer was concentrated under reduced pressure. After adding 700 g of hexane to the concentrate and stirring, the supernatant was removed, and the remaining oily part was concentrated under reduced pressure to obtain 115.7 g of carboxylic acid P3, which was a brown oil (yield 87.4%).

[0139] 26.6 g of carboxylic acid (P3), 31.1 g of benzyltrimethylammonium 2-hydroxy-1,1-difluoroethanesulfonate (S3), 1 g of N,N-dimethylaminopyridine, 17 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 200 g of dichloromethane were mixed, and the mixture was stirred at room temperature overnight. After that, 100 g of 10% mass fraction of benzyltrimethylammonium chloride aqueous solution was added and stirred, and then the organic layer was separated. The organic layer was washed with 100 g of pure water, 100 g of dilute hydrochloric acid and 100 g of pure water in sequence, and then concentrated under reduced pressure. Diisopropyl ether was added to the concentrate, and after stirring, the supernatant was removed to obtain a yellow oil. Next, 50 g of THF and 50 g of 5% hydrochloric acid were added and mixed, and stirred at 40 ° C overnight. 50 g of 10% sodium bicarbonate aqueous solution was added to the solution to quench the reaction. Add 200g of dichloromethane and 40g of 1-pentanol to the solution. After stirring, separate the liquids and collect the organic layer. Wash with 100g of deionized water, 100g of 10% benzyltrimethylammonium chloride aqueous solution, and 100g of deionized water in sequence, and concentrate under reduced pressure. Add diisopropyl ether to the concentrate. After stirring, remove the supernatant. Concentrate the remaining oil under reduced pressure. As the solvent is removed, a solid precipitates. Take out the precipitate and dry it in vacuum to obtain 43.5g of light brown solid ammonium salt P4 (yield 84.5%).

[0140] A mixture of 10 g of ammonium salt (Int-4), 8.8 g of triphenylsulfonium methyl sulfate (S4), 20 g of 1-pentanol, 120 g of dichloromethane and 40 g of deionized water was stirred at room temperature for 30 minutes, and then the organic layer was separated. The mixture was washed with 30 g of deionized water, 30 g of 5.0 wt% sodium bicarbonate aqueous solution, 30 g of deionized water, 30 g of dilute hydrochloric acid, and 30 g of deionized water in sequence, concentrated under reduced pressure, and the concentrate was dissolved in methyl isobutyl ketone. The solution was concentrated under reduced pressure again. Diisopropyl ether was added to the concentrate. After stirring, the supernatant was removed. The remaining oil was diluted with 5 g of methanol and stirred. Diisopropyl ether was added to the dilution and stirred for 2 days. Thereafter, a solid was precipitated. The solid precipitate was collected by filtration, washed with diisopropyl ether, and dried in vacuo. 9.6 g (yield 78.7%) of the target sulfonium salt (PAG-1) was obtained.

[0141] [Synthesis Example 2-5] The sulfonium salts (PAG-2 to PAG-5) were synthesized in the same manner as in Synthesis Example 1, except that S1 was replaced by S1-2, S1-3, S1-4, and S1-5 as shown below.

[0142]

[0143] The structures of PAG-2 to PAG-5 are shown below:

[0144]

[0145] [Synthesis Example 6] Synthesis of sulfonium salt (PAG-6)

[0146]

[0147] 100g of chloronorbornene sultone (S5), 78.1g of monoethyl succinate (S6), 5g of N,N-dimethylaminopyridine, 85g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 500g of dichloromethane were mixed, and the mixture was stirred at room temperature overnight. After that, 300g of 10% mass fraction of benzyltrimethylammonium chloride aqueous solution was added and stirred, and then the organic layer was separated. The organic layer was washed with 300g of pure water, 300g of dilute hydrochloric acid and 300g of pure water in turn, and then concentrated under reduced pressure. Diisopropyl ether was added to the concentrate, stirred, and the supernatant was removed to obtain 134.6g of sultone P5 as a white solid with a yield of 82%.

[0148] Dissolve 134.6g of sultone P5 in 400g of tetrahydrofuran, add 13g of magnesium powder and 73g of anhydrous zinc chloride at 0°C, stir at 40°C for one day, lower the reaction temperature to -20°C, add 14.5g of ditriphenylphosphine palladium dichloride, add 61g of ethyl 2-chloroacetate (S2) dropwise, stir at room temperature for 12 hours, and add cold water to quench the reaction. Then add 300g of dichloromethane and stir, and separate the organic layer. Wash the obtained organic layer with 150g of pure water, 150g of dilute hydrochloric acid, 150g of pure water, 150g of 5% sodium bicarbonate aqueous solution, and 150g of pure water in sequence. Evaporate the obtained organic layer under reduced pressure. Then add 200g of THF and 50g of pure water and stir, add 100g of 25% sodium hydroxide aqueous solution dropwise, and stir at 40°C overnight. After that, cool the reaction solution to ice, and add 250g of 10% ammonium chloride aqueous solution dropwise to stop the reaction. After adding 200 g of ethyl acetate and stirring, the organic layer was separated. After washing the organic layer with 100 g of 5% sodium chloride aqueous solution and 100 g of pure water, the obtained organic layer was concentrated under reduced pressure. After adding 700 g of hexane to the concentrate and stirring, the supernatant was removed and the remaining oily part was concentrated under reduced pressure to obtain 135.4 g of carboxylic acid P6 as a white solid (yield 74.7%).

[0149] The method for synthesizing PAG-6 from P6 is consistent with the method for synthesizing P3 to PAG-1 in Example 1.

[0150] [Synthesis Example 7] The synthesis of sulfonium salt (PAG-7) was the same as in Synthesis Example 6, except that P2-1 was replaced by P2-2, and its structure is shown below. The synthesis method of P2-2 was the same as that of P2-1 in Synthesis Example 1.

[0151]

[0152] [Synthesis Example 8] Synthesis of sulfonium salt (PAG-8)

[0153]

[0154] The synthesis method of P8 is consistent with the synthesis method of P5 in Synthesis Example 6, except that the reaction raw materials are replaced with sultone S7 and carboxylic acid P3-2 as shown in the above formula. The method of synthesizing PAG-8 from P8 is consistent with the method from P2 to PAG-1 in Synthesis Example 1.

[0155] The following compound b-1 is a monomer providing a repeating unit (4), the following compound b-2 is a monomer providing a repeating unit (5), the following compound b-3 is a monomer providing a repeating unit (6), and the following compound f-1 is a monomer providing a repeating unit (7).

[0156]

[0157] [Synthesis Example 9]

[0158] Synthesis of polymer B-1

[0159] 65 mol % of the compound b-1, 20 mol % of the compound b-2 and 15 mol % of the compound b-3 were dissolved in 1-methoxy-2-propanol, and 8 mol % of 2,2'-azobisisobutyronitrile was added based on the total amount of monomers to obtain a monomer solution.

[0160] A 500 mL three-necked flask containing 1-methoxy-2-propanol was purged with nitrogen for 30 minutes. After the nitrogen purge, the flask was heated to 80°C while being stirred, and the above-mentioned monomer solution was added dropwise using a dropping funnel for 3 hours. The start time of the addition was taken as the start time of the polymerization, and the polymerization reaction was carried out for 6 hours. After the polymerization was completed, the polymer solution was cooled to below 30°C by water cooling, and was put into 4,000 g of methanol to precipitate a white powder. Thereafter, the precipitated white powder was filtered out. The filtered white powder was prepared into a slurry with 800 g of methanol, washed twice, and filtered out. Thereafter, it was dried at 50°C for 17 hours to obtain a white powder polymer (B-1).

[0161] The polymer (B-1) had an Mw of 7,600 and an Mw / Mn of 1.59.

[0162] The Mw and Mn of polymer B-1 were measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard, using GPC columns (G2000HXL 2, G3000HXL 1, G4000HXL 1) manufactured by Tosoh Corporation, at a flow rate of 1.0 mL / min, tetrahydrofuran as an eluting solvent, and a column temperature of 40° C. The results of the Mw and Mn measurements were used to calculate the degree of dispersion (Mw / Mn).

[0163]

[0164] [Synthesis Example 10]

[0165] Synthesis of polymer F-1

[0166] Take 0.08 mol of f-1 and 0.08 mol of b-2, 0.005 mol of azobisisobutyronitrile and dissolve them in 300 mL of THF (tetrahydrofuran). At the same time, blow nitrogen into the solution for about 10 minutes, stir and react at 70°C for 4 hours, cool to room temperature, concentrate under reduced pressure, dissolve the concentrate in 120 ml of dioxane, inject 4800 ml of pure water to precipitate the resin, and filter it. Dry at 40°C for 24 hours to obtain white solid F-1.

[0167] The chemical formula of the obtained resin is shown in the following chemical formula (F-1). Its weight average molecular weight (Mw) is 4600 and its dispersion degree (Mw / Mn) is 1.27.

[0168]

[0169] <Preparation of Resist Composition>

[0170] PGMEA: Propylene glycol monomethyl ether acetate

[0171] CyH: Cyclohexanone

[0172] GBL: gamma-butyrolactone

[0173]

[0174]

[0175] E-1: Salicylic Acid

[0176] In Examples 1-8 and Comparative Examples 1-2, according to the composition shown in Table 1, photoacid generator A, film-forming resin B, acid diffusion inhibitor D, organic acid E, and fluorine-containing resin F are dissolved in organic solvent C, and after dissolution, the mixture is filtered using a filter (pore size 0.2 μm) to obtain an anti-etching composition.

[0177] On a 12-inch silicon wafer formed with a lower anti-reflective film ("ARC66", manufactured by Nissan Chemical Co., Ltd.), a film with a thickness of 80 nm was formed using the resist composition obtained in the above-mentioned examples and comparative examples, and PAB was performed at 120°C for 60 seconds. Using an ArF excimer laser scanner (Nikon's NSR-S610C, NA=1.30, σ=0.98 / 0.78, 35-degree cross-polar illumination, azimuth polarization illumination, 6% halftone phase shift mask), exposure was performed using a mask with a size of 50 nm line and 100 nm pitch on the wafer, and PEB was performed at 95°C for 60 seconds. Development was performed using a 2.38 mass% TMAH aqueous solution to form a positive pattern of lines and spaces with a size of 50 nm gap and 100 nm pitch. The exposure amount (sensitivity), edge roughness (LWR), and depth of focus (DOF) of the line and space pattern formed at 1:1 were measured.

[0178] The above results are shown in Table 1.

[0179] Table 1

[0180]

[0181]

[0182] As shown in Table 1, the photoacid generator structure including salicylic acid and the benzolactone skeleton structure formed therefrom can improve photosensitivity and have good LWR.

[0183] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A photoacid generator, characterized in that Including the compound represented by the following formula (1): In formula (1), R 1 represents a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms; R 2 represents a divalent hydrocarbon group having 1 to 20 carbon atoms which may be substituted with a heteroatom or may contain a lactone structure; R 3 represents a divalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a heteroatom or which contains a lactone structure; L 1 , L 2 represents a single bond, -CO-O-, -O-CO-, -O-CO-O-, or -O-; R 4 , R 5 , R 6 represents a hydrogen atom, a substituted or unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms; R 1 , Rf 2 each independently represents a hydrogen atom, a fluorine atom or a trifluoromethyl group; Y represents a hydrogen atom or an alkyl group of 1 to 3 carbon atoms; n is 0 or 1, m, r and p are 1 or 2, and s is an integer from 0 to 2; M + is a sulfonium cation represented by the following formula (2) or an iodonium cation represented by the following formula (3); In formula (2) and formula (3), R 7 -R 11 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, R 7 , R 8 and R 9 May bond to each other to form a ring with the sulfur atom to which they are bonded.

2. The photoacid generator according to claim 1, characterized in that R 5 and R 6 represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms.

3. The photoacid generator according to claim 1, characterized in that L 1 is -CO-O-, m is 1, Rf 1 and Rf 2 It is a fluorine atom.

4. The photoacid generator according to claim 3, characterized in that n is 1, R 2 It is a polycyclic alkane structure containing sultone.

5. A resist composition, characterized in that The invention comprises the photoacid generator as claimed in any one of claims 1 to 4.

6. The resist composition according to claim 5, characterized in that A copolymer comprising a repeating unit selected from the group consisting of the following formula (4), formula (5) and formula (6); In formula (4) to formula (6), R 12 Each is independently a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; In formula (4), R 13 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a substituent; In formula (5), R 14 is hydrogen or alkyl, R 15 is hydrogen, alkyl, alkoxy, acyl or acyloxy, R 15 Some or all of the hydrogen atoms may be substituted, and b is an integer from 1 to 3; In formula (6), c is an integer of 1 to 3.

7. The resist composition according to claim 6, wherein Also included are polymers of repeating units represented by formula (5) and formula (7), wherein the repeating unit represented by formula (7) is as follows: In formula (7), R 12 is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and l, k and t are each independently an integer of 1-5.

8. The resist composition according to claim 6, wherein With respect to 100 mol % of the copolymer, the structure represented by formula (4) accounts for 30 to 70 mol %, the structure represented by formula (5) accounts for 10 to 50 mol %, and the structure represented by formula (6) accounts for 1 to 10 mol %.

9. The resist composition according to claim 7, wherein The polymer of repeating units represented by formula (5) and formula (7) accounts for 1 to 5 wt % of the polymer of repeating units represented by formula (4), formula (5) and formula (6).

10. A method for forming a resist pattern, characterized in that: A step of forming a resist film on a substrate using the resist composition according to any one of claims 6 to 9, exposing the resist film to high-energy radiation, and developing the resist film to obtain a pattern.

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