A bridge-structure photoresist resin and KrF photoresist composition and preparation method thereof

Abstract

The present invention belongs to the field of photoresist technology, and specifically relates to a bridge-type structure photoresist resin and a KrF photoresist composition and a preparation method thereof. The preparation method of the bridge-type structure photoresist resin comprises the following steps: S1, polymerizing a first monomer, a second monomer, and a third monomer in the presence of an initiator to obtain a copolymerization product, wherein the first monomer is 4-acetoxystyrene, the second monomer has a structure represented by formula (1), and the third monomer has a structure represented by formula (2); S2, hydrolyzing the copolymerization product obtained in step S1 in the presence of a catalyst to obtain the bridge-type structure photoresist resin. The bridge-type structure photoresist resin and KrF photoresist composition thus prepared have high resolution, high sensitivity, and good chemical stability.

Description

Technical Field

[0001] The invention belongs to the technical field of photoresists, and in particular relates to a bridge-structure photoresist resin and a KrF photoresist composition and a preparation method thereof. Background Art

[0002] Photolithography is a crucial semiconductor manufacturing process used to transfer patterns onto silicon wafers, creating the microstructures of integrated circuits. The primary function of photoresist during the lithography process is to act as a template for the photomask, restricting light to specific areas and thereby forming the desired microstructures on the silicon wafer. KrF photoresist, which is exposed under KrF (krypton fluoride) laser irradiation, is a key material used in the photolithography process in semiconductor manufacturing. Due to the shorter wavelength and higher energy of KrF lasers, higher resolution and smaller feature sizes can be achieved, making KrF photoresist widely used in the manufacture of various high-density, high-performance microelectronic devices, including microprocessors, memory devices, sensors, and optical devices. However, conventional photoresist materials can suffer from resolution limitations or photoresist depletion at high resolutions. Therefore, given the urgent need for higher-resolution and higher-performance microelectronic devices, the search for photoresist resins and KrF photoresist compositions with high resolution, high sensitivity, and excellent chemical stability is of great significance. Summary of the Invention

[0003] One of the purposes of the present invention is to provide a method for preparing a bridge-type structure photoresist resin with high resolution, high sensitivity and good chemical stability in view of the defects of the prior art photoresist resin in terms of insufficient resolution, sensitivity and chemical stability.

[0004] Specifically, the preparation method of the bridge structure photoresist resin provided by the present invention comprises the following steps:

[0005] S1. Polymerizing a first monomer, a second monomer, and a third monomer in the presence of an initiator to obtain a copolymer product, wherein the first monomer is 4-acetoxystyrene, the second monomer has a structure represented by formula (1), and the third monomer has a structure represented by formula (2);

[0006] S2, hydrolyzing the copolymerized product obtained in step S1 in the presence of a catalyst to obtain a product containing a bridge-structured photoresist resin;

[0007]

[0008] In formula (1), R2 is an acid-sensitive group, and R3 is H or a methyl group.

[0009] In a preferred embodiment, the molar ratio of the first monomer M1, the second monomer, and the third monomer is (4-8):(4-8):1.

[0010] In a preferred embodiment, in step S1, the polymerization reaction conditions include a temperature of 70 to 100° C. and a time of 20 to 28 hours.

[0011] In a preferred embodiment, in step S2, the hydrolysis reaction time is 10 to 15 hours.

[0012] In a preferred embodiment, the structural formula of the acid-sensitive group is selected from one of the following structures:

[0013]

[0014] In a preferred embodiment, the method for preparing the bridge-structure photoresist resin further comprises, after the hydrolysis reaction, subjecting the hydrolysis product to an electrophilic substitution reaction with a compound containing a high ultraviolet absorption group.

[0015] In a preferred embodiment, the molar ratio of the compound containing a high ultraviolet absorption group to the first monomer is (0-0.5):1.

[0016] In a preferred embodiment, the compound containing a high ultraviolet absorption group is selected from at least one of 1-methyl-2-naphthol, 4-methyl-1-naphthol, 9-hydroxy-10-methylanthracene, 9-methylhydroxy-10-methylanthracene, 3-hydroxy-9-methylphenanthrene and 2-hydroxymethyl-9-methylphenanthrene;

[0017] In a preferred embodiment, the structural formula of the high ultraviolet absorption group is selected from one of the following structures:

[0018]

[0019] In a preferred embodiment, the method for preparing the bridge-type structure photoresist resin further comprises adding a precipitant to the reaction solution obtained in step S2 to perform a precipitation reaction, and performing solid-liquid separation to obtain a solid product, which is the bridge-type structure photoresist resin.

[0020] A second object of the present invention is to provide a bridge-structured photoresist resin prepared by the above method.

[0021] In a preferred embodiment, the bridge-type structure photoresist resin has a structural unit represented by formula (4), a structural unit represented by formula (5), and a structural unit represented by formula (6);

[0022]

[0023] In formula (4), R1 is OH or a high UV absorption group;

[0024] In formula (5), R2 is an acid-sensitive group, and R3 is H or a methyl group.

[0025] A third object of the present invention is to provide a KrF photoresist composition, which contains the above-mentioned bridge-structure photoresist resin, a surfactant, an acid quencher, a photoacid generator and an organic solvent.

[0026] In a preferred embodiment, the content of the bridge structure photoresist resin is 10-20 wt %, the content of the surfactant is 0.001-0.1 wt %, the content of the acid quencher is 0.001-0.1 wt %, the content of the photoacid generator is 0.05-6 wt %, and the content of the organic solvent is 74-88 wt %.

[0027] In a preferred embodiment, the surfactant is a fluorine-containing surfactant.

[0028] In a preferred embodiment, the acid quencher is at least one selected from tetrabutylammonium hydroxide, triisopropanolamine, trog's base and 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0029] In a preferred embodiment, the photoacid generator is selected from sulfonium salts and / or iodonium salts.

[0030] In a preferred embodiment, the organic solvent is selected from at least one of ether solvents, ester solvents, ketone solvents and hydroxyl-containing solvents.

[0031] A fourth object of the present invention is to provide a method for preparing the above-mentioned KrF photoresist composition, which comprises uniformly mixing a bridge-structure photoresist resin, a surfactant, an acid quencher, a photoacid generator and an organic solvent to obtain the KrF photoresist composition.

[0032] The key to the present invention lies in the free radical polymerization of 4-acetoxystyrene (the first monomer), an acrylate containing an acid-sensitive group (the second monomer), and 1,5-cyclooctadiene (COD, the third monomer) with a bridged structure. The resulting bridged-structure photoresist resin and KrF photoresist composition exhibit high resolution, high sensitivity, and excellent chemical stability. This is likely due to the fact that, by leveraging the advantages of the COD bridged structure and incorporating a monomer containing a low-activation-energy deprotected acidic group (acid-sensitive group) into the photoresist resin backbone, the transmittance control of the photoresist can be improved, along with the image resolution and lithographic performance under conventional cross-linking conditions, resulting in high-resolution and well-formed photoresist patterns.

[0033] In a preferred embodiment, the introduction of a high ultraviolet absorption group structure into the side chain of the bridge-type structure photoresist resin can enhance the photosensitivity, selectivity and anti-interference performance of the photoresist, thereby improving the effect of the lithography process. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a V-SEM image of the critical dimension of the KrF photoresist composition obtained in Example 1.

[0035] Figure 2 This is a V-SEM image of the critical dimension of the KrF photoresist composition obtained in Example 2.

[0036] Figure 3 This is a critical dimension scanning electron microscope (V-SEM) image of the reference KrF photoresist composition obtained in Comparative Example 1.

[0037] Figure 4 This is a critical dimension scanning electron microscope (V-SEM) image of the reference KrF photoresist composition obtained in Comparative Example 2. DETAILED DESCRIPTION

[0038] The preparation method of the bridge structure photoresist resin provided by the present invention comprises the following steps:

[0039] S1. polymerizing a first monomer, a second monomer, and a third monomer in the presence of an initiator to obtain a copolymer product, wherein the first monomer is 4-acetoxystyrene, the second monomer has a structure represented by formula (1), and the third monomer has a structure represented by formula (2);

[0040] S2. The copolymerization product obtained in step S1 is hydrolyzed in the presence of a catalyst to obtain a product containing a bridge-type structure photoresist resin;

[0041]

[0042] In formula (1), R2 is an acid-sensitive group, and R3 is H or a methyl group.

[0043] In the present invention, the molar ratio of the first monomer, the second monomer, and the third monomer is preferably (4-8):(4-8):1. Based on 1 mol of the third monomer, the molar ratio of the first monomer is preferably 4-8 mol, such as 4 mol, 5 mol, 6 mol, 7 mol, 8 mol, or any value therebetween; the molar ratio of the second monomer is preferably 4-8 mol, such as 4 mol, 5 mol, 6 mol, 7 mol, 8 mol, or any value therebetween.

[0044] In the present invention, in step S1, the conditions of the polymerization reaction include a temperature preferably of 70 to 100°C, such as 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C or any value therebetween; and a time preferably of 20 to 28h, such as 20h, 21h, 22h, 23h, 24h, 25h, 26h, 27h, 28h or any value therebetween.

[0045] In the present invention, in step S2, the hydrolysis reaction time is preferably 10 to 15 hours, such as 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours or any value therebetween.

[0046] In the present invention, the preparation method of the bridge-type structure photoresist resin further comprises, after the hydrolysis reaction, subjecting the hydrolyzate to an electrophilic substitution reaction with a compound containing a high ultraviolet absorption group. The molar ratio of the compound containing a high ultraviolet absorption group to the first monomer is preferably (0 to 0.5):1. Taking the molar number of the first monomer as 1 mol, the molar number of the first monomer is preferably 0 to 0.5 mol, such as 0 mol, 0.1 mol, 0.2 mol, 0.3 mol, 0.4 mol, 0.5 mol or any value therebetween. The photoresist containing a high ultraviolet absorption group can effectively absorb ultraviolet light, exhibits higher sensitivity and responsiveness when using ultraviolet light for photolithography, can produce clearer and finer patterns, and further improves the sensitivity and resolution of the photoresist.

[0047] In the present invention, the compound containing a high ultraviolet absorption group is preferably a compound having a condensed ring aromatic hydrocarbon structure. Specifically, the compound containing a high ultraviolet absorption group can be illustratively selected from at least one of 1-methyl-2-naphthol, 4-methyl-1-naphthol, 9-hydroxy-10-methylanthracene, 9-methylhydroxy-10-methylanthracene, 3-hydroxy-9-methylphenanthrene and 2-hydroxymethyl-9-methylphenanthrene.

[0048] In the present invention, the method for preparing the bridge-type photoresist resin may further include adding a precipitant to the reaction solution obtained in step S2 to perform a precipitation reaction, and performing solid-liquid separation. The resulting solid product is the bridge-type photoresist resin. The precipitant is preferably selected from at least one of deionized water, methanol, ethanol, ether, and petroleum ether. The precipitation reaction time is 1 to 5 hours, such as 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or any value therebetween.

[0049] In a specific embodiment, the preparation method of the bridge structure photoresist resin may include the following steps:

[0050] S1 `. Under nitrogen protection at room temperature, the third monomer, the second monomer and the first monomer M1 and the optional first monomer M2 are dissolved in a first organic solvent to form a mixed monomer solution to be polymerized, the initiator is weighed and dissolved in the first organic solvent to form an initiator solution, the initiator solution is added dropwise to the mixed monomer solution to be polymerized, the temperature is raised to 70 to 100 ° C for polymerization for 20 to 28h to obtain a copolymer product;

[0051] S2 `. The catalyst was added to the copolymer product obtained in step S1 `, and stirring was continued under nitrogen at room temperature, and the hydrolysis reaction was carried out for 10 to 15h to obtain a reaction solution;

[0052] S3`. The reaction solution obtained in step S3` is mixed with a precipitant, and the mixture is stirred and reacted for 1 to 5 hours. The resulting precipitate is filtered, washed, and then vacuum-dried at 60 to 80°C to obtain a bridge-structured photoresist resin.

[0053] In the present invention, the initiator is preferably at least one selected from azobisisobutyronitrile, azobisisoheptylnitrile, dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, dibenzoyl peroxide, cumene peroxide, and tert-butyl peroxide. The amount of the initiator used is not specifically limited in the present invention, as long as it can initiate the polymerization reaction of the monomers to be polymerized.

[0054] In the present invention, the first organic solvent is preferably at least one selected from propylene glycol methyl ether acetate (PGMEA), tetrahydrofuran, cyclopentanone, cyclohexanone, ethyl lactate, butyl acetate, 2-ethoxyethanol and ethyl 3-ethoxypropionate.

[0055] In the present invention, the catalyst is preferably at least one selected from ethanolamine, triethylamine, ammonium acetate, trimethylamine, and dimethylaminopyridine.

[0056] In the present invention, the bridge-type structure photoresist resin preferably has a structural unit represented by formula (4), a structural unit represented by formula (5), and a structural unit represented by formula (6);

[0057]

[0058] In formula (4), R1 is OH or a high UV absorption group;

[0059] In formula (5), R2 is an acid-sensitive group, and R3 is H or a methyl group.

[0060] In a specific embodiment, the bridge-type structure photoresist resin may have the following formula (7):

[0061]

[0062] In formula (7), R1 is OH or a high ultraviolet absorption group, R2 is an acid-sensitive group, R3 is H or a methyl group, x1, x2, x3, and x4 represent the proportion of the first monomer in the bridge-type structure photoresist resin, y1, y2, y3, and y4 represent the proportion of the second monomer in the bridge-type structure photoresist resin, and z1, z2, z3, and z4 represent the proportion of the third monomer in the bridge-type structure photoresist resin, wherein x1+x2+x3=x4=x, y1+y2+y3+y4=y, z1+z2+z3+z4=z, and x+y+z=1. It should be noted that the bridge-type structure photoresist resin shown in formula (7) is only used to represent the monomer structural units contained and the content of each monomer structural unit, and is not used to represent the connection relationship between the monomer structural units. These three monomer structural units can exist in the form of random copolymers, alternating copolymers, or block copolymers, preferably in the form of random copolymers.

[0063] In the present invention, the KrF photoresist composition preferably contains a bridge-type structure photoresist resin, a surfactant, an acid quencher, a photoacid generator, and an organic solvent. Based on the total mass of the KrF photoresist composition, the content of the bridge-type structure photoresist resin is preferably 10 to 20 wt%, such as 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, or any value therebetween. The content of the surfactant is preferably 0.001 to 0.1 wt%, such as 0.001 wt%, 0.005 wt%, 0.01 wt%, 0.02 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, or any value therebetween. The content of the acid quencher is 0.001-0.1wt%, such as 0.001wt%, 0.005wt%, 0.01wt%, 0.02wt%, 0.05wt%, 0.08wt%, 0.1wt% or any value therebetween. The content of the photoacid generator is 0.05-6wt%, such as 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt% or any value therebetween. The content of the organic solvent is 74-88wt%, such as 74wt%, 76wt%, 78wt%, 80wt%, 82wt%, 84wt%, 86wt%, 88wt% or any value therebetween.

[0064] In the present invention, the surfactant is preferably a fluorinated surfactant, which helps to improve the flatness of the film, improve the adhesion between the photoresist compound and the substrate, and reduce the residual film after development. Specific examples include but are not limited to: at least one of perfluorooctane sodium sulfate (PFOS), perfluorooctane ammonium sulfonate (PFAS), perfluorooctyl polyether (PFPE) and perfluorooctane glycolate (PFOA).

[0065] In the present invention, specific examples of the acid quencher include, but are not limited to, at least one of tetrabutylammonium hydroxide (TBAH), triisopropanolamine, trog's base, and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

[0066] In the present invention, the photoacid generator is preferably selected from sulfonium salts and / or iodonium salts, wherein the sulfonium salt is preferably selected from at least one of the compounds having the structure shown below. The iodonium salt is preferably selected from at least one of diphenyl iodine trifluoromethanesulfonate, bis(4-tert-butylphenyl)iodonium perfluoro-1-butanesulfonic acid, bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate, and diphenyl iodonium hexafluorophosphate.

[0067]

[0068] In the present invention, the organic solvent is preferably selected from at least one of ether solvents, ester solvents, ketone solvents and hydroxyl-containing solvents, and specific examples thereof include but are not limited to at least one of propylene glycol methyl ether acetate (PGMEA), cyclopentanone, cyclohexanone, ethyl lactate, butyl acetate, 2-ethoxyethanol and ethyl 3-ethoxypropionate.

[0069] The present invention will be described in detail below through specific examples.

[0070] Preparation Example 1 Preparation of Bridge Structure Photoresist Resin

[0071] S1. Under nitrogen protection at room temperature, 36.2 g of 4-acetoxystyrene (first monomer), 36.2 g of 1-ethylcyclopentyl methacrylate (second monomer), 3.62 g of 1,5-cyclooctadiene (COD, third monomer), and 500 g of PGMEA were weighed and added to a 1 L flask. 0.362 g of azobisisovaleronitrile (AMBN) was weighed and dissolved in 50 mL of PGMEA. The AMBN / PGMEA solution was then slowly added dropwise to the flask. After the addition was complete, the mixture was refluxed at 85°C for 24 h.

[0072] S2. Stop heating, weigh 12.8 g of ethanolamine and add it to the flask. Stir the reaction under nitrogen at room temperature for 12 h.

[0073] S3. After the reaction is completed, the reaction solution is poured into a methanol solution and stirred thoroughly for 3 hours. The resulting precipitate is filtered and rinsed with a large amount of methanol. After vacuum drying at 65°C, 60g of a white solid resin sample is obtained, which is a bridge-type structure photoresist resin (Mw = 10000g / mol). It is mixed with PGMEA to form a solution A-1 with a solid content of 50wt% for standby use.

[0074] Preparation Example 2 Preparation of Bridge Structure Photoresist Resin

[0075] S1. Under nitrogen protection at room temperature, 36.2 g of 4-acetoxystyrene (first monomer), 36.2 g of 1-ethylcyclopentyl methacrylate (second monomer), 3.62 g of 1,5-cyclooctadiene (COD, third monomer), and 500 g of PGMEA were weighed and added to a 1 L flask. 100 mL of tetrahydrofuran was then added to dissolve the mixture. Nitrogen was then introduced with stirring for 1 h to deoxygenate the mixture. 0.362 g of dimethyl azoisobutyrate (AIBME) was weighed and dissolved in 50 mL of PGMEA. The AIBME / PGMEA solution was then slowly added dropwise to the flask. After the addition was complete, the mixture was refluxed at 85°C for 24 h.

[0076] S2. Stop heating, weigh 36 g of amine acetate and 5 mL of deionized water, add the ammonium acetate / water mixture dropwise to the reaction solution, then add 9.3 g of 1-methyl-2-naphthol, and stir the reaction under nitrogen at room temperature for 12 h;

[0077] S3. After the reaction is completed, the reaction solution is poured into 1L of deionized water and stirred thoroughly for 3h. The resulting precipitate is filtered and rinsed with a large amount of deionized water. After vacuum drying at 65°C, 63g of a pink-white solid resin sample is obtained, which is a bridge-type structure photoresist resin (Mw = 15000g / mol). It is mixed with PGMEA to form a solution A-2 with a solid content of 50wt% for standby use.

[0078] Preparation Example 3 Preparation of Bridge Structure Photoresist Resin

[0079] S1. Under nitrogen at room temperature, 42.3 g of 4-acetoxystyrene (first monomer), 58.5 g of 1-ethylcyclopentyl methacrylate (second monomer), 3.62 g of 1,5-cyclooctadiene (COD, third monomer), and 500 g of PGMEA were weighed and added to a 1 L flask. 0.362 g of dimethyl azoisobutyrate (AIBME) was dissolved in 50 mL of PGMEA. The AIBME / PGMEA solution was then slowly added dropwise to the flask. After the addition was complete, the mixture was refluxed at 100°C for 20 h.

[0080] S2. Stop heating, weigh 12.8 g of ethanolamine and add it to the flask. Stir the reaction under nitrogen at room temperature for 10 h.

[0081] S3. After the reaction is completed, the reaction solution is poured into a methanol solution and stirred thoroughly for 3 hours. The resulting precipitate is filtered and rinsed with a large amount of methanol. After vacuum drying at 65°C, 60g of a white solid resin sample is obtained, which is a bridge-type structure photoresist resin (Mw = 13000g / mol). It is mixed with PGMEA to form a solution A-3 with a solid content of 50wt% for standby use.

[0082] Preparation Example 4 Preparation of Bridge Structure Photoresist Resin

[0083] S1. Under nitrogen protection at room temperature, 24.4 g of 4-acetoxystyrene (first monomer), 33.7 g of 1-ethylcyclooctyl methacrylate (second monomer), 3.62 g of 1,5-cyclooctadiene (COD, third monomer), and 500 g of PGMEA were weighed and added to a 1 L flask. 100 mL of tetrahydrofuran was then added to dissolve the mixture. Nitrogen was stirred and introduced for deoxygenation for 1 h. 0.362 g of azobisisovaleronitrile (AMBN) was weighed and dissolved in 50 mL of PGMEA. The AMBN / PGMEA solution was then slowly added dropwise to the flask. After the addition was complete, the mixture was refluxed at 70°C for 28 h.

[0084] S2. Stop heating, weigh 36g of amine acetate and 5mL of deionized water, add the ammonium acetate / water mixture dropwise to the reaction solution, then add 16.7g of 9-hydroxy-10-methylanthracene, and stir the reaction under nitrogen at room temperature for 15h;

[0085] S3. After the reaction is completed, the reaction solution is poured into 1L of deionized water and stirred thoroughly for 3h. The resulting precipitate is filtered and rinsed with a large amount of deionized water. After vacuum drying at 65°C, 63g of a pink-white solid resin sample is obtained, which is a bridge-type structure photoresist resin (Mw = 18500g / mol). It is mixed with PGMEA to form a solution A-4 with a solid content of 50wt% for standby use.

[0086] Example 1 Preparation of KrF Photoresist Composition

[0087] The solution A-1 obtained in Preparation Example 1 was mixed with 3 wt % of triphenylsulfonium perfluorobutanesulfonate, 0.03 wt % of triisopropanolamine, 0.003 wt % of a fluorine-containing surfactant, and a PGMEA and ethyl lactate solution in a ratio of 3:7 to prepare 300 g of a KrF photoresist composition having a bridge-type structure photoresist resin solid content of 13.5 wt %, which was recorded as B-1.

[0088] Example 2 Preparation of KrF Photoresist Composition

[0089] A KrF photoresist composition was prepared according to the method of Example 1, except that solution A-1 was replaced by solution A-2 of the same mass. Other conditions were the same, to obtain a KrF photoresist composition B-2.

[0090] Example 3 Preparation of KrF Photoresist Composition

[0091] A KrF photoresist composition was prepared according to the method of Example 1, except that solution A-1 was replaced by solution A-3 of the same mass. Other conditions were the same, to obtain a KrF photoresist composition B-3.

[0092] Example 4 Preparation of KrF Photoresist Composition

[0093] A KrF photoresist composition was prepared according to the method of Example 1, except that solution A-1 was replaced by solution A-4 of the same mass. Other conditions were the same, to obtain a KrF photoresist composition B-4.

[0094] Comparative Example 1 Preparation of Reference Photoresist Resin and KrF Photoresist Composition

[0095] (1) Preparation of reference photoresist resin

[0096] S1. Under nitrogen at room temperature, 36.2 g of 4-acetoxystyrene, 1.21 g of 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 36.2 g of 1-ethylcyclopentyl methacrylate, and 500 g of PGMEA were added to a 1-L flask. 0.362 g of azobisisovaleronitrile (AMBN) was dissolved in 50 mL of PGMEA. The AMBN / PGMEA solution was then slowly added dropwise to the flask. After the addition was complete, the mixture was refluxed at 85°C for 24 h.

[0097] S2. Stop heating, weigh 12.8 g of ethanolamine and add it to the beaker. Stir the reaction under nitrogen at room temperature for 12 h.

[0098] S3. After the reaction is completed, the reaction solution is poured into a methanol solution and stirred thoroughly for 3 hours. The resulting precipitate is filtered and rinsed with a large amount of methanol. After vacuum drying at 65°C, 55g of a pink solid resin sample is obtained, which is the reference photoresist resin (Mw = 10000g / mol). It is mixed with PGMEA to form a solution DA-1 with a solid content of 50wt% for standby use.

[0099] (2) Preparation of reference KrF photoresist composition

[0100] A reference KrF photoresist composition was prepared according to the method of Example 1, except that solution A-1 was replaced by solution DA-1 of the same mass. Other conditions were the same, to obtain a reference KrF photoresist composition DB-1.

[0101] Comparative Example 2 Preparation of Reference Photoresist Resin and KrF Photoresist Composition

[0102] (1) Preparation of reference photoresist resin

[0103] A reference photoresist resin was prepared according to the method of Preparation Example 1, except that 1,5-cyclooctadiene (COD, the third monomer) was replaced by cyclooctene in the same molar amount. Other conditions were the same to obtain a reference photoresist resin solution DA-2.

[0104] (2) Preparation of reference KrF photoresist composition

[0105] A reference KrF photoresist composition was prepared according to the method of Example 1, except that solution A-1 was replaced by solution DA-2 of the same mass. Other conditions were the same, to obtain a reference KrF photoresist composition DB-2.

[0106] Test Case

[0107] The KrF photoresist compositions of the above examples and comparative examples were coated on an 8-inch silicon wafer (spin coating speed 1500 rpm, uniform coating thickness ), baked at 130°C for 60 seconds to remove the solvent, and then exposed to light using an exposure machine (exposure wavelength 248nm). The exposed silicon wafer was baked at the temperature indicated in the "PEB" column in Table 1 (90°C) for 60 seconds, followed by development in 2.38wt% tetramethylammonium hydroxide (TMAH) developer to obtain the photolithographic pattern. The sensitivity, film thickness change before and after development, and development resolution profile at the same resolution were tested, and the results are shown in Table 1. The photolithographic performance was also compared using V-SEM images of the sample sections.

[0108] Table 1

[0109]

[0110]

[0111] As shown in Table 1, the bridge-type photoresist resin and KrF photoresist composition prepared in the embodiment of the present invention have higher sensitivity at the same resolution than the comparative example. By comparing the V-SEM images of the patterns obtained in the embodiment and the comparative example, it can be seen that the pattern obtained in the embodiment has a better morphological effect. Specifically, Figure 1 and Figure 2 It can be seen that at the same resolution, the edge flatness of the patterns obtained in Example 1 and Example 2 is better, which shows that the bridge-type structure photoresist grafted with COD type monomer has a significant improvement effect on the pattern morphology. Figure 3 and Figure 4 As can be seen, at the same resolution, while the film thickness change before and after development in Comparative Examples 1 and 2 is not significant, the resulting patterns exhibit poor edge flatness, lack of development, and poor pattern morphology, indicating that the structural resins exhibit poor lithographic performance and fail to meet process window requirements. In summary, the bridge-structured photoresist resin and KrF photoresist composition provided by the present invention exhibit high resolution and high sensitivity, minimal film thickness change before and after development, and excellent chemical stability.

[0112] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A method for preparing a bridge-type structure photoresist resin, characterized in that: The preparation method comprises the following steps: S1. Polymerizing a first monomer, a second monomer, and a third monomer in the presence of an initiator to obtain a copolymer product, wherein the first monomer is 4-acetoxystyrene, the second monomer has a structure represented by formula (1), and the third monomer has a structure represented by formula (2); S2, hydrolyzing the copolymer obtained in step S1 in the presence of a catalyst, and subjecting the hydrolyzate to an electrophilic substitution reaction with a compound containing a high ultraviolet absorption group to obtain a product containing a bridge-structured photoresist resin; In formula (1), R2 is an acid-sensitive group, and R3 is H or methyl; The bridge-type photoresist resin has a structure as shown in formula (7): In formula (7), R1 is OH or a high ultraviolet absorption group.

2. The method for preparing a bridge-type structure photoresist resin according to claim 1, wherein: The molar ratio of the first monomer, the second monomer and the third monomer is (4-8):(4-8):

1.

3. The method for preparing a bridge-type structure photoresist resin according to claim 1, wherein: In step S1, the polymerization reaction conditions include a temperature of 70 to 100° C. and a time of 20 to 28 hours.

4. The method for preparing a bridge structure photoresist resin according to claim 1, wherein: In step S2, the hydrolysis reaction time is 10 to 15 hours.

5. The method for preparing a bridge-type structure photoresist resin according to claim 1, wherein: The structural formula of the acid-sensitive group is selected from one of the following structures:

6. The method for preparing a bridge-structure photoresist resin according to claim 1, wherein: The molar ratio of the compound containing a high ultraviolet absorption group to the first monomer is (0-0.5):

1.

7. The method for preparing a bridge-type structure photoresist resin according to claim 1, wherein: The compound containing a high ultraviolet absorption group is selected from at least one of 1-methyl-2-naphthol, 4-methyl-1-naphthol, 9-hydroxy-10-methylanthracene, 9-methylhydroxy-10-methylanthracene, 3-hydroxy-9-methylphenanthrene and 2-hydroxymethyl-9-methylphenanthrene.

8. The method for preparing a bridge-structure photoresist resin according to claim 1, wherein: The structural formula of the high ultraviolet absorption group is selected from one of the following structures; 9. The method for preparing a bridge-structure photoresist resin according to any one of claims 1 to 8, wherein: The preparation method further comprises adding a precipitant to the reaction solution obtained in step S2 to carry out a precipitation reaction, and performing solid-liquid separation, and the obtained solid product is the bridge-structured photoresist resin.

10. A bridge-type structure photoresist resin prepared by the method according to any one of claims 1 to 9, characterized in that: The bridge-type structure photoresist resin has a structural unit represented by formula (4), a structural unit represented by formula (5), and a structural unit represented by formula (6); In formula (4), R1 is OH or a high UV absorption group; In formula (5), R2 is an acid-sensitive group, and R3 is H or a methyl group.

11. A KrF photoresist composition, characterized in that The KrF photoresist composition contains the bridge-structure photoresist resin according to claim 10, a surfactant, an acid quencher, a photoacid generator and an organic solvent.

12. The KrF photoresist composition according to claim 11, characterized in that Based on the total mass of the KrF photoresist composition, the content of the bridge structure photoresist resin is 10-20wt%, the content of the surfactant is 0.001-0.1wt%, the content of the acid quencher is 0.001-0.1wt%, the content of the photoacid generator is 0.05-6wt%, and the content of the organic solvent is 74-88wt%.

13. The KrF photoresist composition according to claim 11, characterized in that The surfactant is a fluorine-containing surfactant.

14. The KrF photoresist composition according to claim 11, characterized in that The acid quencher is at least one selected from tetrabutylammonium hydroxide, triisopropanolamine, trog's base and 1,8-diazabicyclo[5.4.0]undec-7-ene.

15. The KrF photoresist composition according to claim 11, characterized in that The photoacid generator is selected from sulfonium salts and / or iodonium salts.

16. The KrF photoresist composition according to claim 11, characterized in that The organic solvent is selected from at least one of ether solvents, ester solvents, ketone solvents and hydroxyl-containing solvents.

17. The method for preparing the KrF photoresist composition according to any one of claims 11 to 16, characterized in that: The preparation method comprises the steps of uniformly mixing a bridge-structure photoresist resin, a surfactant, an acid quencher, a photoacid generator and an organic solvent to obtain a KrF photoresist composition.

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