Photoacid generator and photoresist composition containing same

Abstract

The invention discloses a photo-acid generator and a photoresist composition containing the photo-acid generator, and relates to the technical field of photosensitive high polymer materials. The photoacid generator is characterized in that the photoacid generator has a general formula structure as shown in a formula (1): # imgabs0 #, in the formula (1), M + represents an organic cation, Q represents a group containing at least one norcamphene group, X represents an ester group or a sulfonate group, Y represents an aliphatic group or an aromatic group, Z represents a fluorine-containing group, and m represents a positive integer greater than 0. Using a high energy beam, such as an ArF excimer laser, as a light source, can provide a material of degree-resolved fine features, including low linewidth roughness (LWR) and sufficient sensitivity to provide wafer yield.

Description

Technical Field

[0001] The invention relates to the technical field of photosensitive polymer materials, in particular to a photoacid generator and a photoresist composition containing the same. Background Art

[0002] Photoresists are photosensitive films used to transfer images to substrates, and they form negative or positive images. After coating the substrate with photoresist, the coating is exposed to a light source such as ultraviolet light through a patterned photomask, and a resist pattern with a predetermined shape is formed on the resist film through a development process.

[0003] Known photoresists can provide features with resolution and size sufficient for many existing commercial applications. However, to meet the needs of modern technology development, new photoresists that can provide higher resolution images are needed.

[0004] At present, as the base resin of the resist composition used in ArF excimer laser lithography, etc., resin (acrylic resin) etc. are generally used (for example, US8795946B2). As the acid generator used in the chemically amplified resist composition, various acid generators have been proposed so far. Nitrobenzyl sulfonate acid generators, iminosulfonate acid generators, disulfone acid generators, etc. are known. Among them, as the onium salt acid generator, iodonium salts with iodonium ions as cations and sulfonium salts with sulfonium ions as cations have been used in the past.

[0005] However, the development of immersion photoresists for the implementation of ArF lithography is still a challenging issue. Under such circumstances, it is desirable to develop a new acid generator compound and a photoresist composition containing such a compound that can provide a material with highly resolved fine features including low line width roughness (LWR) and sufficient sensitivity to provide wafer throughput. Summary of the invention

[0006] The purpose of the present invention is to solve the above technical problems and provide a photoacid generator and a photoresist composition containing the same.

[0007] The first aspect of the present invention provides a photoacid generator having a general structure as shown in formula (1):

[0008]

[0009] In formula (1), M + represents an organic cation, Q represents a group containing at least one norbornyl group, X represents an ester group or a sulfonate group, Y represents an aliphatic group or an aromatic group, Z represents a fluorine-containing group, and m represents a positive integer greater than 0.

[0010] Furthermore, the Q is a group represented by formula (Q-1) to (Q-8):

[0011]

[0012] The connection position of Q and X is not limited. In formulas (Q-1) to (Q-8), R 1 With R 2 The same or different groups independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, a non-aromatic group containing a heteroatom, an aromatic group, a hydroxyl group, an ester group, or an acid-labile group.

[0013] Furthermore, Y represents a chain alkyl group having 1 to 10 carbon atoms or an aromatic alkyl group having 1 to 20 carbon atoms, and Y may contain fluorine or not; and Z represents a fluorine-containing alkyl group having 1 to 5 carbon atoms.

[0014] Furthermore, the proportion of the number of fluorine atoms in the total number of Y and Z atoms is ≤ 60%.

[0015] Furthermore, M + It represents an ammonium salt, a phosphonium salt, an iodonium salt, a sulfonium salt, a carbonium salt, an oxonium salt, or an organic metal salt.

[0016] As a preferred embodiment, the photoacid generator is selected from formula (1-1) to (1-16):

[0017]

[0018]

[0019] The second aspect of the present invention provides a photoresist composition, comprising the photoacid generator provided by the first aspect of the present invention, and further comprising a resin, a quencher and an organic solvent; preferably, the resin is an acrylic resin; more preferably, the resin comprises an acrylic resin and a fluorine-containing resin.

[0020] Furthermore, based on 100 parts by weight of the resin, the photoresist comprises 0.5 to 60 parts by weight of a photoacid generator and 0.5 to 10 parts by weight of a quencher, and the solid content of the photoresist is 2-20 wt %.

[0021] Furthermore, the photoresist further comprises an additive, and the additive comprises one or more of organic carboxylic acid, phosphorus oxyacid and derivatives thereof; preferably, the additive is added in an amount of 0.01 to 5.0 parts by weight based on 100 parts by weight of the resin.

[0022] A third aspect of the present invention provides a method for forming a relief pattern, comprising the steps of:

[0023] (1) applying the photoresist composition provided by the second aspect of the present invention on a substrate to form a coating;

[0024] (2) Exposing the coating in step (1) to activating radiation and developing to obtain a relief pattern.

[0025] Compared with the prior art, the present invention has the following advantageous effects: the present invention provides a novel photoacid generator and a photoresist composition comprising the novel acid generator, which uses a high-energy beam such as an ArF excimer laser as a light source, and can provide a material with fine features with high resolution, including low line width roughness (LWR) and sufficient sensitivity to provide wafer yield. DETAILED DESCRIPTION

[0026] The present invention provides a photoacid generator and a photoresist composition containing the same. The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various improvements within the concept of the present invention may be made without departing from the spirit or scope of the present invention.

[0027] <Photoacid generator>

[0028] The first aspect of the present invention provides a photoacid generator having a general structure as shown in formula (1):

[0029]

[0030] In formula (1), M + represents an organic cation, Q represents a group containing at least one norbornyl group, X represents an ester group or a sulfonate group, Y represents an aliphatic group or an aromatic group, Z represents a fluorine-containing group, and m represents a positive integer greater than 0.

[0031] In some embodiments of the present invention, Q is a group represented by formula (Q-1) to (Q-8):

[0032]

[0033] The connection position of Q and X is not limited. In formulas (Q-1) to (Q-8), R 1 With R 2 The same or different, each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a non-aromatic group containing a heteroatom, an aromatic group, a hydroxyl group, an ester group, or an acid-labile group. The acid-labile group refers to a group that can be decomposed in an acidic environment, and may be an acid-labile group in the monomer of the following formula (4).

[0034] Furthermore, Y represents a chain alkyl group having 1 to 10 carbon atoms or an aromatic alkyl group having 1 to 20 carbon atoms, and Y may contain fluorine or not; preferably, Y is a chain alkyl group having 1 to 5 carbon atoms.

[0035] Furthermore, the Z represents a fluorinated alkyl group having 1 to 5 carbon atoms, such as a chain alkyl group or a cyclic alkyl group.

[0036] Furthermore, the proportion of fluorine atoms in the total number of atoms of Y and Z is ≤ 60%. The content of F atoms affects the light transmittance and hydrophobicity of the resist coating.

[0037] Furthermore, M + represents an ammonium salt, a phosphonium salt, an iodonium salt, a sulfonium salt, a carbonium salt, an oxonium salt, and an organic metal salt. Examples thereof include triphenylsulfonium cation, tri-1-naphthylsulfonium cation, tri-tert-butylphenylsulfonium cation, 4-fluorophenyl-diphenylsulfonium cation, di-4-fluorophenyl-phenylsulfonium cation, tri-4-fluorophenylsulfonium cation, 4-cyclohexylphenyl-diphenylsulfonium cation, 4-methanesulfonylphenyl-diphenylsulfonium cation, 4-cyclohexanesulfonyl-diphenylsulfonium cation, 1-naphthyldimethylsulfonium cation, 1-naphthyldiethylsulfonium cation, 1-(4-hydroxynaphthyl)dimethylsulfonium cation, 1-(4-methylnaphthyl)dimethylsulfonium cation, 1-(4-methylnaphthyl)diethylsulfonium cation, 1-(4-cyanonaphthyl) dimethylsulfonium cation, 1-(4-cyanonaphthyl)diethylsulfonium cation, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophenium cation, 1-(4-methoxynaphthyl)tetrahydrothiophenium cation, 1-(4-ethoxynaphthyl)tetrahydrothiophenium cation, 1-(4-n-propoxynaphthyl)tetrahydrothiophenium cation, 1-(4-n-butoxynaphthyl)tetrahydrothiophenium cation, 2-(7-methoxynaphthyl)tetrahydrothiophenium cation, 2-(7-ethoxynaphthyl)tetrahydrothiophenium cation, 2-(7-n-propoxynaphthyl)tetrahydrothiophenium cation, 2-(7-n-butoxynaphthyl)tetrahydrothiophenium cation and the like.

[0038] In some specific embodiments of the present invention, the photoacid generator is selected from formula (1-1) to (1-16):

[0039]

[0040]

[0041] The synthesis route of the photoacid generator of the present invention is not limited, and an example that can be cited is: a carboxylic acid derivative containing norbornyl is sequentially reacted with thionyl chloride, a sodium hydroxysulfonate derivative, and an organic cationic halogen salt such as triphenyl bromide to obtain the photoacid generator. The reaction route is as follows:

[0042]

[0043] Q, X, Y, and Z in formula (2) or formula (3) are the same as in formula (1).

[0044] <Photoresist composition>

[0045] The second aspect of the present invention provides a photoresist composition, comprising the photoacid generator provided by the first aspect of the present invention, and further comprising a resin, a quencher and an organic solvent. Further, based on 100 parts by weight of the resin, the photoresist comprises 0.5 to 60 parts by weight of the photoacid generator and 0.5 to 10 parts by weight of the quencher, and the solid content of the photoresist is 2-20wt%.

[0046] The resin in the photoresist composition of the present invention is not limited in type, as long as it has the ability to form a film, such as acrylic resin. The resin of the present invention preferably contains one or more repeating units containing acid-labile groups, such as a polymer formed by polymerization of monomers of acrylate or methacrylate compounds and acid-labile groups, the monomer containing acid-labile groups includes but is not limited to one or more of the following structures, and the repeating units containing acid-labile groups account for more than 15 mol% of all repeating units of the resin, preferably more than 20 mol%, and more preferably more than 30 mol%.

[0047]

[0048] In the above formula (4), R a It is H, F, -CN, C 1-6 Alkyl or C 1-6 Fluoroalkyl.

[0049] The resin of the present invention may also contain repeating units having a lactone structure, and the content of the repeating units having a lactone structure is preferably 5 mol% to 60 mol% relative to all repeating units in the resin (A), more preferably 5 mol% to 55 mol%, and even more preferably 10 mol% to 50 mol%. It may be a monomer represented by formula (5):

[0050]

[0051] R in formula (5) b It is H, F, -CN, C 1-6 Alkyl or C 1-6 Fluoroalkyl, R c It is C 1-10 alkyl, cycloalkyl or heterocycloalkyl, and n is an integer from 0 to 5. In formula (5), R c Directly connected to the lactone ring; the ester part is directly connected to the lactone ring, or through R c Indirect connection. The following examples can be given: Formula (5-1) to Formula (5-3), where R b Same as formula (5).

[0052]

[0053] In consideration of the application of immersion photoresist, in order to improve the hydrophobicity of the photoresist composition, the photoresist composition of the present invention may further add a fluorine-containing resin, and the amount of the fluorine-containing resin added is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, and particularly preferably 1 to 7.5 parts by mass relative to 100 parts by mass of the resin. Examples of fluorine-containing monomers of the following formula (6) may be cited:

[0054]

[0055] The fluorine-containing monomer can be self-polymerized or copolymerized with the following monomer structures (but not limited to the following monomer structures) to form a fluorine-containing resin:

[0056]

[0057] The purpose of the quencher in the photoresist composition of the present invention is to inhibit the diffusion of the acid generated by light, thereby improving the contrast of the photoresist after exposure and development. Based on 100 parts by weight of the resin, the amount of the quencher added is 0.5 to 10 parts by weight, preferably 0.5 to 8 parts by weight, and more preferably 1 to 8 parts by weight.

[0058] The quencher is selected from a photodegradable weak acid salt or a non-photodestructible base. The photodegradable weak acid salt includes a photodegradable cation and a weak acid anion with pKa>2, wherein the cation includes sulfonate, etc., and examples of carboxylic acids include formic acid, acetic acid, propionic acid, tartaric acid, succinic acid, cyclohexyl carboxylic acid, benzoic acid, salicylic acid, etc. The non-photodestructive base is not limited, and examples thereof include hydroxides, alkoxides, carboxylates, amines, imines, amides and other compounds and their corresponding salts, preferably organic amines, imines or amides, such as tripropylamine, decylamine, 1,1′,1″-nitrile tripropan-2-ol, 1,1′,1″,1″′-(ethane-1,2-diyldi(azanetriyl))tetrapropan-2-ol, diphenylamine, triphenylamine, aminophenol, 2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane, Troger's base, diazabicycloundecene (DBU), diazabicyclononene (DBN), or ionic quenchers, including quaternary alkylammonium salts, such as any one or more of tetrabutylammonium hydroxide (TBAH) or tetrabutylammonium lactate.

[0059] The solvent in the photoresist composition of the present invention is not limited to any type, such as lactones, ketones, alcohols, compounds with ester bonds, polyol derivatives, ether compounds, cyclic ethers, etc. The amount of the solvent used in the present invention is not particularly limited, and is a concentration that can be applied to a substrate, etc., and is appropriately set according to the thickness of the coating film, but is generally a solid content. It is preferably used in a range of 2-20wt% of the solid content of the photoresist composition, preferably 2-15wt%.

[0060] Lactone solvents such as γ-butyrolactone; ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-amyl ketone, methyl isoamyl ketone, 2-heptanone; alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol and other polyols; compounds with ester bonds such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate; polyol derivatives such as monomethyl ether, monoethyl ether and monopropyl ester of the above polyols or derivatives of polyols such as compounds with ester bonds; ether compounds such as ethers, monoalkyl ethers such as monobutyl ether or monophenyl ether, preferably propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME). Cyclic ethers such as dioxane; esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate. and other aromatic organic solvents, such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenethyl ether, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, cumene, toluene, xylene, methyl isopropylbenzene, mesitylene. These organic solvents can be used alone or in combination of two or more.

[0061] Preferred are one or more of propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), ethyl lactate (EL), and γ-butyrolactone.

[0062] Or preferably, a mixed solvent of PGMEA and a polar solvent is used. The mixing mass ratio can be appropriately determined in consideration of the compatibility of PGMEA with the polar solvent, and is preferably 1:9 to 9:1, and more preferably 2:8 to 8:2. Specifically, when EL is mixed as a polar solvent, the mass ratio of PGMEA:EL is preferably 1:9 to 9:1, and more preferably 2:8 to 8:2. When PGME is used as a polar solvent, the mass ratio of PGMEA:PGME is preferably 1:9 to 9:1, and more preferably 2:8 to 8:2, and further preferably 3:7 to 7:3.

[0063] Alternatively, a mixed solvent of at least one of PGMEA and EL and γ-butyrolactone is preferred. In this case, the mixing mass ratio of the former to the latter is preferably 70:30 to 95:5.

[0064] Alternatively, a mixed solvent of PGMEA and PGME and a mixed solvent of γ-butyrolactone are preferred.

[0065] As a preferred embodiment of the present invention, the photoresist composition provided in the second aspect of the present invention may further include an additive, wherein the additive includes one or more of an organic carboxylic acid, an oxyphosphorus acid and its derivatives; preferably, the additive is added in an amount of 0.01 to 5.0 parts by weight based on 100 parts by weight of the resin. The addition of organic carboxylic acid, oxyphosphorus acid and its derivatives can prevent sensitivity degradation and improve the resist pattern shape, storage stability, etc.

[0066] The type of the organic carboxylic acid is not limited, and examples thereof include any one or more of acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid or salicylic acid; preferably salicylic acid.

[0067] The type of the phosphorus oxyacid is not limited, and examples thereof include any one or more of phosphoric acid, phosphonic acid, phosphinic acid, etc.; preferably, phosphonic acid.

[0068] The derivative of the phosphorus oxyacid is an ester that can be obtained by replacing the hydrogen atoms of the phosphorus oxyacid with a hydrocarbon group, an aromatic group, etc., and the types are not limited to phosphates, phosphonates, and phosphinates. Examples include: di-n-butyl phosphate, diphenyl phosphate, dimethylphosphonic acid, di-n-butylphosphonic acid, phenylphosphonic acid, diphenylphosphonic acid, dibenzylphosphonic acid, or phenylphosphinate.

[0069] As other preferred embodiments of the present invention, the photoresist composition provided in the second aspect of the present invention may also include additional resins for improving the properties of the resist film, surfactants for improving coating properties, solubilizers, inhibitors, plasticizers, stabilizers, colorants, anti-halation agents may be appropriately added and contain dyes, dyes, etc.

[0070] <Method of Forming Relief Pattern>

[0071] The third aspect of the present invention provides a method for forming a relief pattern, comprising the steps of: (1) applying the photoresist composition provided by the second aspect of the present invention on a substrate to form a coating; and (2) exposing the coating in step (1) to activating radiation and developing to obtain a relief pattern.

[0072] The substrate suitable for the application and processing of the resist of the present invention is any substrate used for photoresist processes, such as microelectronic wafers. For example, the substrate can be a silicon, silicon dioxide or aluminum-aluminum oxide microelectronic wafer. Gallium arsenide, ceramic, quartz or copper substrates can also be used. Substrates for liquid crystal displays and other flat panel display applications are also suitable for use, such as glass substrates, indium tin oxide coated substrates, etc.

[0073] The photoresist composition can be applied to the substrate by any standard means such as spin coating, dip coating or roller coating. The exposure energy should be sufficient to effectively excite the photoactive components in the photosensitive system to form an image with a pattern on the coating of the resist. The radiation used at this time can be appropriately selected such as ultraviolet rays, KrF excimer laser (wavelength 248nm), ArF excimer laser (wavelength 193nm), F2 excimer laser (wavelength 157nm), EUV (far ultraviolet light, wavelength 13nm, etc.), charged particle rays such as electron rays, synchrotron radiation, etc. X-rays, but among them, far ultraviolet rays and electron rays are preferred. Exposure conditions such as exposure amount are appropriately selected according to the mixed composition of the radiation-sensitive resin composition, the types of various additives, etc., and the typical range of exposure energy is about 1-300mJ / cm 2 .

[0074] In order to stably form a fine pattern with high precision, it is preferred to perform a heat treatment after exposure. A suitable post-exposure baking temperature is from about 50°C or higher, more particularly from about 50 to 140°C.

[0075] After development and post-development curing, the substrate surface exposed by the development step can then be selectively processed, and the developer used in the development is preferably an alkaline aqueous solution such as tetramethylammonium hydroxide dissolved therein. The concentration of the alkaline aqueous solution is usually below 10 wt%.

[0076] Example

[0077] The above and other advantages of the present invention may be better understood through the following examples, but the following examples are not intended to limit the scope of the present invention.

[0078] Synthesis example 1

[0079]

[0080] 36.0g 4,7-methyl-1H-indene-2-carboxylic acid, 28.5g thionyl chloride and 200ml toluene were added to a 300ml eggplant flask equipped with a stirrer, Dimroth condenser, thermometer and water separator in sequence, and stirred for 1 hour. After the reaction solution was cooled to room temperature, 24.3g triethylamine was added, and 26.4g diethylene glycol monovinyl ether (DEGV) was added dropwise over 30 minutes while stirring the reaction solution. The reaction was completed by stirring at room temperature for 12 hours. After filtering the reaction solution to remove salts, it was washed 3 times with 100ml saturated sodium bicarbonate aqueous solution and once with 100ml saturated brine. The organic layer was dried with magnesium sulfate and then concentrated to obtain 48.3g donor monomer (b-2) (yield 82%). The obtained donor monomer (b-2) was dissolved in dichloromethane with triethylamine and N,N,N,N'-tetramethylethylenediamine. Then, add sodium 1,1,2-trifluoro-4-hydroxybutane sulfonate at below 15°C and raise the temperature to 20°C. Then, stir for 3 hours and cool the reaction solution to below 15°C. Add 8% sodium bicarbonate aqueous solution to stop the reaction. Then, add dichloromethane and stir to extract the target product in the dichloromethane layer. Then, repeatedly wash the organic layer with distilled water until the pH of the separated water layer reaches 7. Then, distill off the solvent by rotary evaporator to obtain donor monomer (b-3) (yield 85%);

[0081]

[0082] The obtained donor monomer (b-3) and triphenylthiobromide were dissolved in dichloromethane in an equimolar ratio, stirred for 3 hours, and the reaction solution was cooled to below 15°C. An 8% sodium bicarbonate aqueous solution was added to stop the reaction. Then, dichloromethane was added and stirred, and the target product was extracted from the dichloromethane layer. The organic layer was then repeatedly washed with distilled water until the pH of the separated water layer reached 7. Then, the solvent was distilled off by a rotary evaporator to obtain a photoacid generator (B-1) (yield 95%).

[0083] Synthesis Examples 2 to 10

[0084] Photoacid generators (B-2) to (B-10) were synthesized in the same route as in Synthesis Example 1, except that the carboxylic acid derivatives containing norbornane were used as raw materials. The amount of carboxylic acid derivatives and sodium sulfonate added was selected according to the prepared photoacid generator.

[0085] Photoacid generator (B-2):

[0086]

[0087] Photoacid generator (B-3):

[0088]

[0089] Photoacid generator (B-4):

[0090]

[0091] Photoacid generator (B-5):

[0092]

[0093] Photoacid generator (B-6):

[0094]

[0095] Photoacid generator (B-7):

[0096]

[0097] Photoacid generator (B-8):

[0098]

[0099] Photoacid generator (B-9):

[0100]

[0101] Photoacid generator (B-10):

[0102]

[0103] Examples and Comparative Examples

[0104] The photoacid generators obtained in Synthesis Examples 1 to 10 and the following resins, fluorine-containing resins, quenchers, additives and solvents were mixed in the proportions shown in Table 1 to obtain photoresist composition solutions. The obtained photoresist composition solutions were subjected to various evaluations. The evaluation results are shown in Table 2.

[0105] Table 1: Composition of photoresist composition solutions in various embodiments

[0106]

[0107] Each abbreviation in Table 1 has the following meaning. In addition, the numerical value in [ ] is the compounding amount (parts by mass).

[0108] Resin (A-1):

[0109]

[0110] Quencher (D-1): tri-n-pentylamine.

[0111] Additive (E-1): salicylic acid.

[0112] Fluorine-containing resin (F-1): fluorine-containing polymer compound (Mw = 8000, Mw / Mn = 1.40, composition ratio l / m = 74.2 / 25.8 (molar ratio))

[0113]

[0114] Solvent (S-1): γ-butyrolactone; Solvent (S-2): a mixed solvent of PGMEA / PGME=6 / 4 (mass ratio).

[0115] Weight average molecular weight (Mw) and number average molecular weight (Mn): measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard.

[0116] <Photolithography Characteristics Evaluation>

[0117] Using the resist compositions shown in Table 1, resist patterns were formed by the resist pattern forming method shown below, and the lithography properties were evaluated.

[0118] On a 6-inch silicon wafer, an organic anti-reflection film composition "ARC95" (manufactured by BrewerScience) was applied using a spin coater, baked on a hot plate at 205°C for 60 seconds, and a dried organic anti-reflection film was formed to a thickness of 90 nm. Then, the resist compositions in Table 1 were applied to the organic anti-reflection film using a spinner, and the coating post-baking (PAB) was performed on a hot plate at 120°C for 60 seconds, and then dried. A resist film with a thickness of 95 nm was formed. Next, using an ArF immersion exposure system "NSR-S609B" (manufactured by Nikon Corporation, NA (numerical aperture) = 1.07, Crosspole, immersion medium: water), the resist film was selectively irradiated with ArF excimer laser (193 nm) through a mask pattern (6% halftone). Then, a post-exposure baking (PEB) treatment was performed at 95°C for 60 seconds, and an alkali development treatment was performed at 23°C for 10 seconds using a 2.38% by mass tetramethylammonium hydroxide aqueous solution. Rinse for 30 seconds and spin dry.

[0119] Evaluation of pattern LWR: In the formed 1:1 L / S pattern, the line width and line length were measured at 50 points in the direction by length measurement SEM "S-9380" (scanning electron microscope, accelerating voltage 300V, manufactured by Hitachi, Ltd.), and three times the standard deviation (s) (3s) was calculated from the results as the measured value of LWR. The results are shown in Table 2. The smaller the 3s value, the smaller the line width roughness, which means that a more uniform L / S pattern is obtained.

[0120] Table 2 Evaluation of photoresist compositions of various examples

[0121] Example PAB / PEB(℃) LWR(nm) Example 1 120 / 95 5.43 Example 2 120 / 95 4.83 Example 3 120 / 95 4.62 Example 4 120 / 95 4.32 Example 5 120 / 95 4.79 Example 6 120 / 95 4.54 Example 7 120 / 95 4.37 Comparative Example 1 120 / 95 6.95 Comparative Example 2 120 / 95 7.21

[0122] As described above, compared with Comparative Examples 1-2, the resist compositions 1-7 obtained by using the photoacid generator provided by the present invention are more excellent in LWR and can provide materials with high-resolution fine features.

Claims

1. A photoacid generator, characterized in that It has the general structure shown in formula (1): In formula (1), M + represents an organic cation, Q represents a group containing at least one norbornyl group, X represents an ester group or a sulfonate group, Y represents an aliphatic group or an aromatic group, Z represents a fluorine-containing group, and m represents a positive integer greater than 0.

2. The photoacid generator according to claim 1, characterized in that The Q is a group represented by formula (Q-1) to (Q-8): The connection position of Q and X is not limited. In formulas (Q-1) to (Q-8), R1 and R2 are the same or different, and each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a non-aromatic group containing a heteroatom, an aromatic group, a hydroxyl group, an ester group, or an acid-labile group.

3. The photoacid generator according to claim 1, characterized in that The Y represents a chain alkyl group having 1 to 10 carbon atoms or an aromatic alkyl group having 1 to 20 carbon atoms, and Y may contain fluorine or not; and Z represents a fluorine-containing alkyl group having 1 to 5 carbon atoms.

4. The photoacid generator according to claim 3, characterized in that: The proportion of fluorine atoms in the total number of Y and Z atoms is ≤ 60%.

5. The photoacid generator according to claim 1, characterized in that: M + It represents an ammonium salt, a phosphonium salt, an iodonium salt, a sulfonium salt, a carbonium salt, an oxonium salt, or an organic metal salt.

6. The photoacid generator according to claim 1, characterized in that: The photoacid generator is selected from formula (1-1) to (1-16):

7. A photoresist composition comprising the photoacid generator according to any one of claims 1 to 6, characterized in that: The method comprises a resin, a quencher and an organic solvent; preferably, the resin is an acrylic resin; more preferably, the resin comprises an acrylic resin and a fluorine-containing resin.

8. The photoresist composition according to claim 7, characterized in that Based on 100 parts by weight of the resin, the photoresist comprises 0.5 to 60 parts by weight of a photoacid generator and 0.5 to 10 parts by weight of a quencher, and the solid content of the photoresist is 2-20 wt %.

9. The photoresist composition according to claim 7, characterized in that: The photoresist further comprises an additive, and the additive comprises one or more of organic carboxylic acid, phosphorus oxyacid and derivatives thereof; preferably, the additive is added in an amount of 0.01 to 5.0 parts by weight based on 100 parts by weight of the resin.

10. A method for forming a relief pattern using the photoresist composition according to any one of claims 7 to 9, characterized in that: Includes steps: (1) applying the photoresist composition on a substrate to form a coating; (2) Exposing the coating in step (1) to activating radiation and developing to obtain a relief pattern.

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