Photoacid generator, resist composition, and pattern forming method

Abstract

The application provides a photoacid generator, a resist composition and a pattern forming method, and relates to the technical field of photoetching materials. The photoacid generator has a general formula represented by structural formula (1). In the structural formula (1), R1 and R2 are each independently selected from a hydrogen atom, a C1-C30 monovalent hydrocarbon group, a C1-C30 monovalent hydrocarbon group substituted by an oxygen atom or an oxygen atom-containing group, and R1 and R2 do not contain a carbon-carbon double bond; R3 is a single bond or a C1-C3 alkyl group; R4, R5, R6 and R7 are each independently a hydrogen atom, a fluorine atom or a C1-C3 fluorinated alkyl group; and n ranges from 0 to 10. The photoacid generator can improve the photosensitivity and CER / LWR performance of a resist film pattern in a resist composition.

Description

Technical Field

[0001] This application relates to the field of photolithography materials technology, and in particular to a photoacid-generating agent, a photoresist composition, and a patterning method. Background Technology

[0002] In the manufacturing processes of semiconductor devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integrated Circuits), photolithography is a core step in achieving microfabrication. It uses a resist composition (photoresist) to form a pre-defined pattern on the wafer surface, providing a precise mask for subsequent etching, ion implantation, and other processes, directly determining the integration density and performance of the semiconductor device. Chemically amplified photoresists, a core material in the photolithography process, typically consist of photosensitive resin, photoacid generator, quencher, and solvent. The photoacid generator is a key component for achieving the chemical amplification effect, acting as a "photo-chemical" converter, transforming light energy into chemical energy during the photolithography process, directly affecting key performance indicators such as the photoresist's sensitivity, resolution, and LWR (Light Reflectance Ratio).

[0003] Photoacid generators are a class of photosensitive compounds that undergo photochemical reactions and decompose to produce strong acids (H⁺) under the action of an exposure light source. After exposure, the strong acid produced during the post-exposure baking process acts as a catalyst, causing the acid-unstable groups (such as tert-butyloxycarbonyl, acetal, etc.) in the photosensitive resin molecules to undergo deprotection reactions and fall off, thereby changing the polarity of the photosensitive resin. The polarity of the resin in the exposed area is significantly enhanced, making it more soluble in the developer, while the polarity of the resin in the unexposed area remains unchanged and it is insoluble in the developer. Finally, the development process yields a fine pattern corresponding to the photomask, completing the micro-processing of the wafer.

[0004] Besides developing new photolithography processes and chemically amplifying photoresists, researching and improving photoacid generators is also crucial to meeting the rapid advancements in current microfabrication technologies. Currently, ionic ononium salt photoacid generators are widely used in industry, consisting of ononium cations (such as triphenylthionium) and sulfonic acid anions (mostly perfluoroalkyl sulfonic acid anions). Because they can generate more potent perfluoroalkyl sulfonic acids, they can efficiently catalyze the deprotection reaction of photosensitive resins, improving the sensitivity of photoresists and adapting to the demands of high-resolution photolithography.

[0005] However, commonly used perfluoroalkyl sulfonate photoacid generators in existing technologies produce perfluoroalkyl sulfonic acids during exposure decomposition. Substances such as perfluorooctane sulfonic acid (PFOS) are highly biotoxic, difficult to degrade, and accumulate persistently in the environment, posing potential hazards to the ecological environment and human health. Although some existing technologies attempt to replace perfluoroalkyl sulfonic acid anions with fluorine-free alkyl sulfonic acid anions, these fluorine-free photoacid generators produce insufficient acid strength and lack the electron-withdrawing properties of fluorine atoms to stabilize the acid anions. They cannot efficiently catalyze the deprotection reaction of high-activation-energy photosensitive resins, making them unsuitable for the demands of advanced photolithography processes, resulting in a significant decrease in the sensitivity and resolution of the photoresist.

[0006] Therefore, developing a novel photo-generating acid agent and its preparation method to solve the problems of large LWR and low resolution in traditional photoresist compositions has become an urgent technical problem to be solved in the field of semiconductor photolithography materials. Summary of the Invention

[0007] This application provides a photoacid generator, a photoresist composition, and a pattern formation method. The photoacid generator in the photoresist composition can improve the photosensitivity and CER / LWR performance of the photoresist film pattern, while also improving the solubility of the photoresist composition in organic developer and improving the development defects of the photoresist film.

[0008] In a first aspect, this application provides a photo-induced acid-generating agent, comprising:

[0009] The photo-induced acid-producing agent has the general formula represented by structural formula (1).

[0010] (1)

[0011] In the structural formula (1), R1 and R2 are each independently selected from hydrogen atoms, C1~C30 monovalent hydrocarbon groups, C1~C30 monovalent hydrocarbon groups substituted by oxygen atoms or oxygen-containing groups, R1 and R2 do not contain carbon-carbon double bonds, R3 is a single bond, C1~C3 alkyl, R4, R5, R6 and R7 are each independently selected from hydrogen atoms, fluorine atoms or C1~C3 fluoroalkyl groups, and n ranges from 0 to 10.

[0012] In one possible implementation, in the structural formula (1), R1 and R2 are each independently selected from unsubstituted, ether-bonded or ester-bonded C1-C30 monovalent hydrocarbon groups containing steroidal skeletons, unsubstituted, ether-bonded or ester-bonded C1-C20 monovalent hydrocarbon groups containing adamantane skeletons, and unsubstituted, ether-bonded or ester-bonded C1-C15 straight-chain, branched or cyclic monovalent hydrocarbon groups.

[0013] In one possible implementation, in the structural formula (1), R1 and R2 are each independently selected from the following structural formulas:

[0014]

[0015] Preferably, R1 and R2 are each independently selected from the following structural formulas:

[0016]

[0017] More preferably, R1 and R2 are each independently selected from the following structural formulas:

[0018] .

[0019] In one possible implementation, in the structural formula (1), R3 is a single bond and n ranges from 0 to 2.

[0020] In a second aspect, this application provides an anti-corrosion composition comprising: a host resin (A), a fluorinated resin (B), an acid diffusion control agent (C), an organic solvent (D), and a molecular photoacid generator (E) as described in any of the embodiments of the first aspect above.

[0021] In one possible implementation, the amount of the main resin (A) added is 80-100 parts by weight, the amount of the fluorinated resin (B) added is 0.1-10 parts by weight, the amount of the acid diffusion control agent (C) added is 1-5 parts by weight, and the amount of the molecular photoacid generator (E) added is 1-5 parts by weight.

[0022] In one possible embodiment, the resist composition further includes an ionic photoacid generator (F), which has the general formula represented by structural formula (4).

[0023] (4)

[0024] In the structural formula (4), m ranges from 1 to 5.

[0025] In one possible implementation, the amount of the molecular photoacid generator (E) added is 1 to 5 parts by mass, and the amount of the ionic photoacid generator (F) added is 1 to 15 parts by mass.

[0026] In one possible implementation, the mass ratio of the molecular photoacid generator (E) to the ionic photoacid generator (F) is 1:(2~4).

[0027] Thirdly, this application provides a method for forming a resist pattern, comprising the following steps:

[0028] S1, Coating: The photoresist composition described in any one of the embodiments of the second aspect above is applied to a substrate and cured thereon to form a photoresist film;

[0029] S2, Immersion Exposure: After drying, light of a specific wavelength is penetrated through the liquid medium, and then ArF excimer laser is used to irradiate a specific area of ​​the photoresist film to perform immersion exposure.

[0030] S3, Development: After baking, the exposed photoresist film is developed using a developing solution to obtain a photoresist pattern.

[0031] In the above technical solution, by adding a photoacid generator with a structural formula (1) to the photoresist composition, the side group of the photoacid generator contains groups such as ether bond, ester group or alkyl chain, which enables it to have good compatibility with photoresist resin, can be well dispersed in photoresist layer, reduce acid diffusion length, and thus form a photoresist pattern with improved photosensitivity and CER / LWR. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0033] It should be understood that the term "and / or" as used in this application specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0034] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0035] It should be noted that the following embodiments are examples of this application and are used only to illustrate this application, and are not intended to limit this application. Other combinations and various modifications within the scope of this application are possible without departing from the spirit or scope of this application.

[0036] The photo-induced acid-generating agent, resist composition, and pattern formation method provided in this application are described in detail below.

[0037] The photoacid-producing agent of this application embodiment has the general formula represented by structural formula (1).

[0038] (1)

[0039] In structural formula (1), R1 and R2 are each independently selected from hydrogen atoms, C1~C30 monovalent hydrocarbon groups, C1~C30 monovalent hydrocarbon groups substituted by oxygen atoms or oxygen-containing groups. R1 and R2 do not contain carbon-carbon double bonds. R3 is a single bond, C1~C3 alkyl group. R4, R5, R6, and R7 are each independently selected from hydrogen atoms, fluorine atoms, or C1~C3 fluoroalkyl groups. The range of n is 0~10.

[0040] When radiation irradiates the photoacid generator described above, it produces a strong acid, and the acetal portion dissociates. The resulting OH groups combine with the deprotected resin COOH, controlling acid diffusion and thus achieving control over photosensitivity and CER / LWR. By adding ether, ester, or alkyl groups to the side groups of the photoacid generator, it achieves good compatibility with the photoresist resin, allowing it to disperse well in the photoresist layer and reducing the acid diffusion length. This results in a resist pattern with improved photosensitivity and CER / LWR.

[0041] Furthermore, in structural formula (1), R1 and R2 are each independently selected from unsubstituted, ether-bonded, or ester-based C1-C30 monovalent hydrocarbon groups containing steroidal skeletons, unsubstituted, ether-bonded, or ester-based C1-C20 monovalent hydrocarbon groups containing adamantane skeletons, and unsubstituted, ether-bonded, or ester-based C1-C15 straight-chain, branched, or cyclic monovalent hydrocarbon groups. The long-chain side groups with cyclic groups can reduce the entanglement between the photoacid generator and the resin chain. Groups with hydroxyl or ether bonds have better compatibility, and the photoacid generator is less likely to aggregate in the resist composition, which can further improve the photosensitivity and LWR performance of the resist pattern.

[0042] Furthermore, in structural formula (1), R1 and R2 are each independently selected from the following structural formulas:

[0043]

[0044] Preferably, R1 and R2 are each independently selected from the following structural formulas:

[0045]

[0046] Adding ether and ester groups to the side groups can further improve the photosensitivity and LWR performance of the resist pattern. More preferably, R1 and R2 are each independently selected from the following structural formulas:

[0047] .

[0048] In this application, in structural formula (1), R3 is a single bond, and n ranges from 0 to 2. Long alkyl chains significantly increase the hydrophobicity of photoacid-producing agents. Excessive hydrophobicity greatly inhibits the diffusion of acid during post-exposure baking (PEB) and leads to uneven acid distribution, thereby increasing CER / LWR.

[0049] Examples of photoacid-producing agents represented by structural formula (1) include the following structures:

[0050] PAG-1 PAG-2

[0051] PAG-3 PAG-4

[0052] PAG-5 PAG-6

[0053] PAG-7 PAG-8

[0054] <Main Resin (A)>

[0055] In this application, the main resin (A) is a polyacrylate derivative, having the general formula represented by structural formula (2).

[0056] (2)

[0057] In structural formula (2), R8 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; R9 is a monovalent hydrocarbon group with 1 to 8 carbon atoms, either substituted or unsubstituted; R10 and R11 are independently monovalent chain hydrocarbon groups with 1 to 8 carbon atoms or monovalent alicyclic hydrocarbon groups with 3 to 12 carbon atoms, or represent a divalent alicyclic hydrocarbon group with 3 to 12 carbon atoms formed by the combination of R10 and R11 and the carbon atoms bonded to R10 and R11.

[0058] The main resin (A) comprises repeating units (A-1), repeating units (A-2), and repeating units (A-3). The repeating unit (A-1) is an acid-sensitive repeating unit, where R8 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R9 to R11 represent monovalent alicyclic hydrocarbon groups with 3 to 20 carbon atoms, and can be listed as the group obtained by removing one hydrogen atom from monocyclic saturated alicyclic hydrocarbons, unsaturated alicyclic hydrocarbons, or alicyclic polycyclic hydrocarbons with 3 to 20 carbon atoms. Specific examples of these alicyclic hydrocarbons include monocyclic saturated alicyclic hydrocarbons such as cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane; and monocyclic unsaturated alicyclic hydrocarbons such as cyclopentene, cyclohexene, cycloheptene, cyclooctene, and cyclodecene. Repeating unit (A-1) can be listed as follows:

[0059]

[0060] In this unit, the repeating unit (A-2) is a lactone repeating unit; it allows for easier adjustment of the solubility of the main resin (A) in the developer, improving adhesion to the substrate and achieving improvements in lithography properties such as resolution. As the repeating unit (A-2), R8 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, and R9-R10 are structural units comprising at least one of the following groups: cyclic lactone structure, cyclic carbonate structure, and sulfonyl lactone structure. Examples of repeating units (A-2) are as follows:

[0061]

[0062] The repeating unit (A-3) is a polar repeating unit. The repeating unit (A-3) adjusts the solubility of the main resin (A) in the developer, thereby improving the film-forming properties of the composition, such as resolution. As a polar group in the repeating unit (A-3), R8 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, and R9-R10 are straight-chain and cyclic alkyl hydrocarbons with hydroxyl, carboxyl, cyano, nitro, or polar groups. Examples of repeating units (A-3) are as follows:

[0063]

[0064] In this application, the main resin (A) is a ternary or quaternary copolymer resin, comprising at least one repeating unit as described in formula (A-1). Among all the structural units constituting the main resin (A), the content of structural unit (A-1) is 10-90 mol%, more preferably 30-60 mol%; the content of at least one repeating unit as described in formula (A-2) is 5-30 mol%, more preferably 15-30 mol%; and the content of at least one repeating unit as described in formula (A-3) is 5-30 mol%, more preferably 15 mol%-30 mol%.

[0065] When the resist composition contains a main resin (A), the amount of main resin (A) added is preferably 80 parts by mass or more, more preferably 85 parts by mass or more, and even more preferably 90 parts by mass or more. Furthermore, the amount of main resin (A) added is preferably 100 parts by mass or less, more preferably 95 parts by mass or less, and even more preferably 90 parts by mass or less.

[0066] Fluoropolymer (B)

[0067] Fluorinated resin (B) is more likely to be present on the surface of the resist film than the host resin (A). Because the CF bonds of fluorinated resin (D) have low surface energy, a unique molecular structure, and stable chemical properties, they can improve the hydrophobicity of the resist film surface during water immersion exposure. Fluorinated resin (B) has the general formula represented by structural formula (3).

[0068] (3)

[0069] In structural formula (3), R12 and R13 are fluoroalkyl groups, and R14 is a monovalent hydrocarbon group of C1 to C30 that may contain heteroatoms.

[0070] When the resist composition contains a fluorinated resin (B), the amount of fluorinated resin (B) added is preferably 0.1 parts by mass or more, preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 5 parts by mass or more. Furthermore, the amount of fluorinated resin (B) added is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 5 parts by mass or less.

[0071] <Acid Diffusion Control Agent (C)>

[0072] Acid diffusion control agent (C) suppresses the diffusion of acid generated by photoacid-generating agents during exposure into the resist film, thereby inhibiting acid-induced chemical reactions in unexposed areas. By incorporating acid diffusion control agent (C) into the resist composition, the performance and photolithographic properties of the resist film can be improved, particularly enhancing the contrast of the resist film to improve resolution.

[0073] As an acid diffusion control agent (C), nitrogen-containing compounds or photodegradable bases can be listed. The photodegradable base used in this application is preferably a triarylsulfonium salt. The structure of the acid diffusion control agent (C) in this application is obtained as follows: C1 to C3, and one or more can be used alone or in combination.

[0074]

[0075] When the resist composition contains an acid diffusion control agent (C), the amount of acid diffusion control agent (C) added is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more. Furthermore, the amount of acid diffusion control agent (C) added is preferably 5 parts by mass or less, more preferably 4.5 parts by mass or less, and even more preferably 4 parts by mass or less. By setting the amount of acid diffusion control agent (C) within the aforementioned range, the LWR performance of the resist composition can be further improved. As the acid diffusion control agent (C), one type can be used alone, or two or more types can be used in combination.

[0076] <Organic Solvents (D)>

[0077] The organic solvent (D) is any solvent capable of dissolving or dispersing the components in the resist composition, and is not particularly limited. Examples of organic solvents (D) include alcohols, ethers, ketones, esters, etc.

[0078] Examples of alcohols include 4-methyl-2-pentanol, n-hexanol, and 1,2-propanediol. Examples of ethers include propylene glycol monomethyl ether (PGME), diisopentyl ether, tetrahydrofuran, and tetrahydropyran. Examples of ketone solvents include cyclohexanone and methyl-2-n-pentyl ketone. Examples of ester solvents include propylene glycol monomethyl ether acetate (PGMEA), n-butyl acetate, ethyl lactate (EL), and γ-butyrolactone.

[0079] Preferred ingredients include one or more of propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), ethyl lactate (EL), and γ-butyrolactone.

[0080] <Molecular photoacid generator (E)>

[0081] The molecular photoacid generator (E) is as described above. The amount of molecular photoacid generator (E) added is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more. Furthermore, the amount of molecular photoacid generator (E) added is preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 3 parts by mass or less.

[0082] <Ionic photoacid generator (F)>

[0083] Ionic photoacid-generating agents (F) have the general formula represented by structural formula (4).

[0084] (4)

[0085] In structural formula (4), m ranges from 1 to 5.

[0086] The amount of ionic photoacid generator (F) added is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 5 parts by mass or more. In addition, the amount of ionic photoacid generator (F) added is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, and even more preferably 9 parts by mass or less.

[0087] The mass ratio of molecular photoacid generator (E) to ionic photoacid generator (F) is 1:(2~4). For example, the mass ratio of molecular photoacid generator (E) to ionic photoacid generator (F) is approximately 1:2, approximately 1:3, or approximately 1:4. By combining molecular photoacid generator (E) and ionic photoacid generator (F), the acid diffusion length can be controlled, resulting in a smaller CER / LWR and a better profile of the photoresist pattern. It can also control the photoresist transmittance, effectively suppressing undercut / side etching and reducing various pattern defects.

[0088] <Pattern Formation Methods>

[0089] This application also provides a pattern forming method, comprising: a step of coating a resist composition onto one surface of a substrate (hereinafter also referred to as a "coating step"); a step of exposing the resist film obtained by the coating step (hereinafter also referred to as an "exposure step"); and a step of developing the exposed resist film (hereinafter also referred to as a "development step").

[0090] Coating process

[0091] The coating of a photoresist composition onto a substrate is typically performed using conventional equipment such as a spin coater. The photoresist composition is preferably filtered using a filter with a pore size of 0.2 μm before coating. Examples of substrates include silicon wafers or quartz wafers on which sensors, circuits, transistors, etc., are to be formed. After coating, a soft bake (SB) is performed to allow the solvent in the coating to evaporate. The SB temperature is preferably 60°C or higher, more preferably 80°C or higher. Furthermore, the SB temperature is preferably 140°C or lower, more preferably 120°C or lower. The SB time is preferably 5 seconds or higher, more preferably 10 seconds or higher. Furthermore, the SB time is preferably 600 seconds or lower, more preferably 300 seconds or lower. The average thickness of the formed photoresist film is preferably 100 nm to 1000 nm, more preferably 100 nm to 500 nm. Furthermore, the SB time is preferably 600 seconds or lower, more preferably 300 seconds or lower.

[0092] Exposure process

[0093] The resulting composite layer is typically exposed using a dry exposure apparatus or a liquid immersion exposure apparatus. Exposure is generally performed through a mask corresponding to the desired pattern. Various types of exposure light sources can be used, such as irradiation with ultraviolet lasers like KrF stimulated excimer lasers (wavelength: 248 nm), ArF stimulated excimer lasers (wavelength: 193 nm), and F2 stimulated excimer lasers (wavelength: 157 nm). Alternatively, the exposure apparatus can be an electron beam exposure apparatus or an extreme ultraviolet (EUV) exposure apparatus. Post-exposure baking (PEB) is performed on the exposed portion of the resist film, utilizing the acid generated by the photoacid after exposure to promote the dissociation of the resin acid containing acid-sensitive groups. This further improves sensitivity. The temperature and time of PEB directly affect the diffusion range and reaction rate of the photoacid, thereby affecting the critical dimension (CD), sidewall angle, and line edge roughness (LER) of the developed pattern.

[0094] The resist composition of the present invention is preferably exposed using an ArF immersion exposure apparatus. The PEB temperature is preferably 50°C or higher, more preferably 80°C or higher. Furthermore, the PEB temperature is preferably 180°C or lower, more preferably 130°C or lower. The PEB time is preferably 5 seconds or higher, more preferably 10 seconds or higher. Furthermore, the PEB time is preferably 600 seconds or lower, more preferably 300 seconds or lower.

[0095] Development process

[0096] After heat treatment, the resist film is developed, typically using an organic developing solution. Development here refers to contacting the resist film with an organic solution after heat treatment. This dissolves and removes the exposed portions of the resist film using the organic solution, leaving the unexposed portions of the composite layer on the substrate, thus creating a resist pattern. Examples of organic developing solutions include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methyl acetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, and methyl valerate. The following are one or more combinations of pentanoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, 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, and 2-phenylethyl acetate.

[0097] Example

[0098] The technical solution of the present invention will be further described below with reference to specific embodiments. The abbreviations corresponding to some compounds involved in the embodiments will be explained below.

[0099] Monomer T-1:

[0100] Monomer T-2:

[0101] Monolithic T-3:

[0102] T-4 monolithic:

[0103] T-5 single unit:

[0104] Fluoropolymer B1:

[0105] Acid diffusion control agent C2:

[0106] Organic solvent D1: Propylene glycol monomethyl ether acetate (PGMEA)

[0107] Organic solvent D2: Propylene glycol monomethyl ether (PGME)

[0108] Ionic photoacid generator F1:

[0109] Synthesis Example 1 (Synthesis of Main Resin A1)

[0110] Monomers T-1 (Shanghai Daran Chemical Co., Ltd.), T-2 (Shanghai Bide Pharmaceutical Technology Co., Ltd.), T-3 (Shanghai Haohong Biomedical Technology Co., Ltd.), T-4 (Shanghai Huaenyi New Material Technology Co., Ltd.), and T-5 (Xi'an Ruilian New Material Co., Ltd.) were prepared at a molar feed ratio of 10 / 10 / 40 / 30 / 10. A feed solution was prepared by dissolving 7.5 g of dimethyl 2,2'-azobis(2-methylpropionic acid) (obtained from the test as V-601) as an azo initiator in 307 g of butanone. 153 g of butanone was added to a three-necked round-bottom flask equipped with a water condenser and thermometer, and the temperature was raised to 65°C. The feed solution was supplied to the reactor using a syringe pump over a 4-hour period, followed by holding at 65°C for another 2 hours. The contents were cooled to room temperature, diluted to 25% by weight with tetrahydrofuran, and precipitated in a 7:3 (w / w) mixture of 10 times (by weight) heptane and methanol. The main resin A1 obtained by filtration was dried under vacuum at 50°C for 24 hours.

[0111] Synthesis Example 2 (Synthesis of Molecular Photoacid-Generating Agent E1)

[0112] S1: At 0°C, 1.0 eq of compound I (Jiangsu Aikon Biomedical R&D Co., Ltd.) was dissolved in 2V tetrahydrofuran, and then added dropwise to a 5V tetrahydrofuran solution containing 1.5 eq of magnesium shavings with a catalytic amount of iodine. The reaction was carried out overnight at room temperature, and then the reaction solution was added to a saturated ammonium chloride solution at 0°C. 3V ethyl acetate was added, the organic layer was separated, and the solution was concentrated under reduced pressure to obtain an oily product II-1.

[0113]

[0114] Ⅰ Ⅱ-1

[0115] S2: Under nitrogen protection, 1.0 eq of compound II-2 (Suzhou Yuanqi Materials Technology Co., Ltd.) was dissolved in 5V tetrahydrofuran. 1.5 eq of intermediate II-1 was added dropwise to the solution under ice bath conditions. The reaction was allowed to proceed overnight at room temperature. The reaction mixture was then added to a saturated ammonium chloride solution at 0°C. 3V ethyl acetate was added, the organic layer was separated, and the solution was concentrated under reduced pressure to obtain a white solid. Diisopropyl ether was added to the product, the precipitated solid was filtered, and the solid was dried under vacuum to obtain white crystalline sulfonium compound III.

[0116]

[0117] II-1 II-2 III

[0118] S3: At 0 °C, a solution of 1.1 eq sodium hydride dissolved in 2 V tetrahydrofuran was added dropwise to a solution of 5 V tetrahydrofuran containing 1.0 eq 2-adamantanol and 1.2 eq intermediate III. The reaction was allowed to proceed overnight at room temperature, and then the reaction mixture was added to a saturated ammonium chloride solution at 0 °C. 3 V ethyl acetate was added, the organic layer was separated, and the mixture was concentrated under reduced pressure to give an oily product. Diisopropyl ether was added to the product, the precipitated solid was filtered, and the solid was dried under vacuum to give white crystalline sulfonium compound IV.

[0119]

[0120] III IV

[0121] S4: At room temperature, a solution of 1.0 eq intermediate IV dissolved in 2V dichloromethane was added dropwise to 5V dichloromethane containing 1.1 eq sodium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate (Suzhou Yuanqi Materials Technology Co., Ltd.) and 0.2 eq iodine. The reaction was carried out at room temperature for 3 hours. The reaction solution was diluted with deionized water, the organic phase was separated, and the solution was concentrated under reduced pressure to obtain a white solid. Diisopropyl ether was added to the product, the precipitated solid was filtered, and the solid was dried under vacuum to obtain white crystalline sulfonium compound E1.

[0122]

[0123] IV E1

[0124] Synthesis Example 3 (Synthesis of Molecular Photoacid-Generating Agent E2)

[0125] The compound II-2 in S2 was replaced with 4-sulfinylfluorobenzene (Shanghai Bid Pharmaceutical Technology Co., Ltd.), and the 2-adamantanol in S3 was replaced with dehydrocholic acid (Sigma-Aldrich (Shanghai) Trading Co., Ltd.). The other steps and raw materials were the same as in Synthesis Example 2, to obtain E2 of the following formula.

[0126] E2

[0127] Synthesis Example 4 (Synthesis of Molecular Photoacid-Generating Agent E3)

[0128] The compound II-2 in S2 was replaced with 4,4'-sulfinylbis(fluorobenzene), the 2-adamantanol in S3 was replaced with 1-adamantanecarboxylic acid (Shanghai Haohong Biomedical Technology Co., Ltd.), and the sodium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate in S4 was replaced with sodium 1,1,3,3,3-pentafluoro-2-hydroxypropane-1-sulfonate. The other steps and starting materials were the same as in Synthesis Example 2, and E3 of the following formula was obtained.

[0129] E3

[0130] Synthetic Examples 5~X

[0131] Photoacid generators E4 to E13 were synthesized following the routes of synthetic examples 2 to 4 above, with the difference being that some raw materials were different, and their structures are shown in the following formula.

[0132] E4 E5

[0133] E6 E7

[0134] E8 E9

[0135] E10 E11

[0136] E12 E13

[0137] <Pattern Formation (ArF Immersion Exposure)>

[0138] An antireflective coating solution (ARC29A, Nissan Chemical Corp.) was applied to a silicon substrate and baked at 200 °C for 60 seconds to form a 100 nm thick ARC. Each resist composition was spin-coated onto the ARC and pre-baked on a hot plate at 100 °C for 60 seconds to form a 95 nm thick photoresist film on the ARC. The resist film was exposed by ArF excimer laser immersion lithography using an ArF immersion scanner (manufactured by ASML, XT1700i, NA1.20, C-Quad, external ∑0.981, internal ∑0.895, XY deflection). Water was used as the immersion solution. The resist film was baked at 90 °C (PEB) for 60 seconds and developed in a butyl acetate solution for 30 seconds. Rinsing was performed using a rinsing solution (4-methyl-2-pentanol) for 30 seconds. The rinsed wafer is rotated at 4000 rpm for 30 seconds and then baked at 90°C for 60 seconds. This yields a 55 nm (1:1) contact hole-pitch resist pattern.

[0139] The performance of photosensitivity and CER was tested according to the following evaluation method.

[0140] (1) Sensitivity

[0141] Observe the 55nm 1:1 contact hole-spacer pattern under SEM. The optimal dose (Eop) is the dose (mJ / cm2) provided to the contact holes at 55nm. Observe the pattern printed with the optimal dose to determine whether its profile is acceptable.

[0142] (2) CER (Surface roughness) of the contact hole edge

[0143] The CD variation of a 55 nm 1:1 contact hole-spacer pattern was measured using SEM (30 points were measured, and the 3σ value was calculated), denoted as CER. A smaller CER value indicates less fluctuation and better profile of the contact hole pattern.

[0144] (3) Defect density evaluation

[0145] The number of defects in the pattern formed after development is checked using the KLA2800 defect inspection device (manufactured by KLA-Tencor Corporation), and the defect density is calculated according to the following formula.

[0146] Defect density (number of defects / cm²) = Total number of defects detected / Inspection area:

[0147] The resulting pattern is a repeating pattern with a 1:1 aperture / pitch ratio of 55nm.

[0148] Defect inspection conditions: UV light source, 0.28μm pixel size, inter-unit mode.

[0149] For resist patterns formed using ArF immersion exposure resist compositions, the photosensitivity, CER, and defect density performance were evaluated according to the method described above.

[0150] Examples 1-14 & Comparative Examples 1-3

[0151] Examples 1-14 and Comparative Examples 1-3 each provide a photoresist composition. The photoresist composition formulation in each example contains: 90.0 parts by weight of main resin A1, 0.6 parts by weight of fluorinated resin B1, 1.0 parts by weight of acid diffusion control agent C2, 1600 parts by weight of organic solvent D1 and 400 parts by weight of organic solvent D2.

[0152] The specific formulations of the resist compositions in each embodiment are shown in Table 1.

[0153]

[0154] Comparing Examples 1-9 and Examples 10 and 11, it is evident that when ether bonds, ester groups, or alkyl chains are added to R1 and R2 of the molecular photoacid generator (E), the resist composition can achieve a lower CER and fewer defect densities at a lower Eop. Comparing Examples 1, 4-5 and Examples 2-3, 6-8, it is evident that when ether bonds, ester groups, and cyclic groups are simultaneously present in R1 and R2 of the molecular photoacid generator (E), the resist composition exhibits optimal Eop, CER, and defect density performance.

[0155] Comparing Examples 7 and 9, and Examples 10 and 11, it can be seen that when the R3 of the molecular photoacid generator (E) is a single bond and the n range is 0~2, the CER and defect density performance of the resist composition are both superior.

[0156] Comparing Examples 1-11 with Comparative Example 1, it can be seen that when the structure of the molecular photoacid generator (E) does not belong to structural formula (1), the defect density performance of the resist composition is poor.

[0157] Comparing Example 1 and Comparative Example 2, it can be seen that when the molecular photoacid generator (E) is changed to an ionic photoacid generator with the same structure, the CER and defect density performance of the resist composition both deteriorate.

[0158] Comparing Examples 1, 12-14 and Comparative Example 3, it can be seen that when the amount of molecular photoacid generator (E) added is 1-5 parts by mass, the Eop, CER and defect density performance of the resist composition are all better. When the amount added is too large, the Eop, CER and defect density performance of the resist composition all deteriorate.

[0159] Examples 15-21 & Comparative Example 4

[0160] Examples 15-21 and Comparative Example 4 each provide a photoresist composition. The photoresist composition formulation in each example contains: 90.0 parts by weight of main resin A1, 0.6 parts by weight of fluorinated resin B1, 1.0 parts by weight of acid diffusion control agent C2, 1600 parts by weight of organic solvent D1 and 400 parts by weight of organic solvent D2.

[0161] The specific formulations of the resist compositions in each embodiment are shown in Table 2.

[0162]

[0163] Comparative Examples 15-17 show that when the mass ratio of molecular photoacid generator (E) to ionic photoacid generator (F) is 1:(2-5), the resist composition exhibits superior Eop, CER, and defect density performance.

[0164] Comparative Examples 16, 18-20 show that when different types of molecular photoacid generators (E) and ionic photoacid generators (F) are used in combination, the Eop, CER and defect density performance of the resist composition are all superior.

[0165] Comparative Examples 20-21 show that when a large amount of ionic photoacid generator (F) is added, the CER and defect density performance of the resist composition deteriorates.

[0166] Comparative Examples 15-20 and Comparative Example 4 show that when only an ionic photoacid generator (F) is added, the Eop, CER and defect density properties of the resist composition all deteriorate.

[0167] Although the embodiments of this application have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this application. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this application is not limited to the specific details and embodiments shown and described herein.

Claims

1. A photo-induced acid-producing agent, characterized in that, include: The photo-induced acid-producing agent has the general formula represented by structural formula (1). (1) In the structural formula (1), R1 and R2 are each independently selected from hydrogen atoms, C1~C30 monovalent hydrocarbon groups, C1~C30 monovalent hydrocarbon groups substituted by oxygen atoms or oxygen-containing groups, R1 and R2 do not contain carbon-carbon double bonds, R3 is a single bond, C1~C3 alkyl, R4, R5, R6 and R7 are each independently selected from hydrogen atoms, fluorine atoms or C1~C3 fluoroalkyl groups, and n ranges from 0 to 10.

2. The photoacid-generating agent according to claim 1, characterized in that, In the structural formula (1), R1 and R2 are each independently selected from unsubstituted, ether-bonded or ester-bonded C1-C30 monovalent hydrocarbon groups containing steroidal skeletons, unsubstituted, ether-bonded or ester-bonded C1-C20 monovalent hydrocarbon groups containing adamantane skeletons, and unsubstituted, ether-bonded or ester-bonded C1-C15 straight-chain, branched or cyclic monovalent hydrocarbon groups.

3. The photoacid-generating agent according to claim 2, characterized in that, In the structural formula (1), R1 and R2 are each independently selected from the following structural formulas: Preferably, R1 and R2 are each independently selected from the following structural formulas: More preferably, R1 and R2 are each independently selected from the following structural formulas: 。 4. The photoacid-generating agent according to any one of claims 1 to 3, characterized in that, In the structural formula (1), R3 is a single bond, and n ranges from 0 to 2.

5. A corrosion resist composition, characterized in that, include: The main resin (A), fluorinated resin (B), acid diffusion control agent (C), organic solvent (D), and molecular photoacid generator (E) as described in any one of claims 1 to 4.

6. The resist composition according to claim 5, characterized in that, The amount of the main resin (A) added is 80-100 parts by weight, the amount of the fluorinated resin (B) added is 0.1-10 parts by weight, the amount of the acid diffusion control agent (C) added is 1-5 parts by weight, and the amount of the molecular photoacid generator (E) added is 1-5 parts by weight.

7. The resist composition according to claim 5, characterized in that, The resist composition further includes an ionic photoacid generator (F), which has the general formula represented by structural formula (4). (4) In the structural formula (4), m ranges from 1 to 5.

8. The resist composition according to claim 7, characterized in that, The amount of the molecular photoacid generator (E) added is 1 to 5 parts by mass, and the amount of the ionic photoacid generator (F) added is 1 to 15 parts by mass.

9. The resist composition according to claim 8, characterized in that, The mass ratio of the molecular photoacid generator (E) to the ionic photoacid generator (F) is 1:(2~4).

10. A method for forming a resist pattern, characterized in that, Includes the following steps: S1, Coating: The photoresist composition according to any one of claims 5 to 9 is applied to the substrate and cured to form a photoresist film; S2, Immersion Exposure: After drying, light of a specific wavelength is penetrated through the liquid medium, and then ArF excimer laser is used to irradiate a specific area of ​​the photoresist film to perform immersion exposure. S3, Development: After baking, the exposed photoresist film is developed using a developing solution to obtain a photoresist pattern.

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