Fluorine-containing resin and immersed photoresist

Abstract

The embodiment of the invention provides fluorine-containing resin and immersed photoresist, and relates to the field of photoresist. In the embodiment of the invention, the fluorine-containing resin contains a first repeating unit with a fluorine-containing side group and an end-capping group with a structural general formula of # imgabs0 #, Rf1 is selected from at least one of fluorine, trifluoromethyl, perfluoroethyl, perfluoropropyl, hexafluoroisopropyl and perfluorobutyl, and n is a positive integer not less than 1. The fluorine-containing resin provided by the embodiment of the invention has good self-aggregation performance, and when the fluorine-containing resin is used as a component of an immersed photoresist, a uniform implantable barrier layer can be formed on the surface of a cured photoresist film to prevent components in the photoresist film from being dissolved in water; and the fluorine-containing resin in the embodiment of the invention is also easy to remove in the developing solution.

Description

Technical Field

[0001] The present application relates to the field of photoresists, and in particular to a fluorine-containing resin and an immersion photoresist. Background Art

[0002] Photoresist (also known as resist composition) is an indispensable raw material for manufacturing semiconductor chips. When preparing chips, photoresist will be coated on the surface of the substrate and cured into a photoresist film. Then, after exposure to light of a specific wavelength, a preset pattern will be photoetched on the film. After development, etching and other steps, the pattern on the film will be transferred to the surface of the chip to form an integrated circuit. When preparing chips, the shorter the wavelength of light, the better the performance of the chip. At present, when preparing mid-to-high-end chips, light with a wavelength of about 193nm is used as the light source, and immersion is used for photolithography.

[0003] In immersion lithography technology, the photoresist coated on the semiconductor substrate needs to be immersed in water and exposed at the excitation wavelength of ArF (i.e., the central wavelength is 193.368nm) after being cured into a film. This requires that the active ingredients in the photoresist cannot be dissolved in water, and the chemical properties do not change after contact with water. This photoresist can be called immersion photoresist (or ArF photoresist).

[0004] Fluorine-containing resin is added to the components of current immersion photoresists. When the photoresist is spin-coated, the fluorine-containing resin will gather on the upper surface of the film to form an embedded barrier layer (EBL), which can prevent the effective components of the photoresist from dissolving out. However, the current fluorine-containing resin has a weak self-aggregation ability and sometimes cannot evenly gather on the surface of the immersion photoresist to form an EBL, causing other components to dissolve in water. In addition, if the self-aggregation ability of the fluorine-containing resin is further improved, it is easy to cause the fluorine-containing resin to be difficult to peel off in the developer, affecting the subsequent etching of the semiconductor. Summary of the invention

[0005] The embodiments of the present application can provide a fluorine-containing resin and an immersion photoresist, which have good self-aggregation properties and can, when used as a component of the immersion photoresist, uniformly form an ELB with good hydrophobic properties and corrosion resistance on the surface of the cured photoresist film; and the fluorine-containing resin in the embodiments of the present application is also easy to peel off in the developer later, thereby improving the etching performance for the semiconductor.

[0006] In a first aspect, the present application provides a fluorine-containing resin having an end-capping group, and the general structural formula of the end-capping group is: Where R f1At least one selected from fluorine, trifluoromethyl, perfluoroethyl, perfluoropropyl, hexafluoroisopropyl, and perfluorobutyl, wherein n is a positive integer not less than 1: and the fluorine-containing resin contains the first repeating unit shown below: Wherein R1 is selected from any one of a hydrogen atom, an alkyl group, and a lactone group; R f2 A fluorine-containing group.

[0007] In the above technical solution, the inventors found that due to the weak interaction between aromatic compounds, when the end-capping group of the fluorine-containing resin contains a benzene ring, the self-aggregation effect of the fluorine-containing resin is stronger, and the molecules can be evenly stacked together; and in the end-capping group, due to the R on the benzene ring f1 The group is selected from at least one of fluorine, trifluoromethyl, perfluoroethyl, perfluoropropyl, hexafluoroisopropyl, and perfluorobutyl, and can also play a role in reducing the surface energy of the fluorine-containing resin, thereby enhancing the hydrophobicity of the fluorine-containing resin. When the fluorine-containing resin is used as a component of an immersion photoresist and the immersion photoresist is spin-coated into a film, the end-capping group can ensure that the fluorine-containing resin is distributed more quickly and evenly on the surface of the film, forming an EBL with better hydrophobicity, which can better prevent the effective components of the photoresist from dissolving; and the first repeating unit of the fluorine-containing resin also has a fluorine-containing group R f2 The side chain can also cooperate with the end-capping group to increase the hydrophobicity of the fluorine-containing resin.

[0008] In addition, in the above technical solution, the end-capping group is connected to the main chain through an ester group. If the fluorine-containing resin is used in an immersion photoresist, the end-capping group can fall off from the main body of the fluorine-containing resin under the action of acid. Therefore, after exposure, the self-aggregation effect of the fluorine-containing resin becomes weak, and it is easy to peel off in the subsequent development process.

[0009] In one possible implementation, R f2 The present invention includes any one of a fluorinated hydrocarbon group having 1 to 30 carbon atoms and a functional group containing a hexafluoroisopropanol alkyl group.

[0010] In one possible implementation, R f2 It is any one of fluorinated hydrocarbon groups having 1 to 30 carbon atoms.

[0011] In a possible implementation, the fluorine-containing resin further contains the second repeating unit shown below: Wherein Rx includes any one of a lactone group and an acid-sensitive group.

[0012] In the above technical solution, in the second repeating unit of the fluorine-containing resin, the Rx group can improve the etching resistance and stability of the fluorine-containing resin. In addition, the presence of the Rx group can also ensure that the fluorine-containing resin can be better matched with the main resin when it is used as one of the components of the immersion photoresist.

[0013] In one possible implementation, the acid-sensitive group includes Any one of; and / or, the inner lipid group includes Any of .

[0014] In a possible implementation, the weight average molecular weight of the fluorine-containing resin is 20,000 to 30,000; and / or the polymer dispersity index (PDI) of the fluorine-containing resin is not greater than 2.5.

[0015] In the above technical solution, the weight average molecular weight and PDI of the fluorine-containing resin are controlled within a suitable range, which is more conducive to the generation of π-π stacking between the end-capping groups, thereby better increasing the self-aggregation performance of the fluorine-containing resin.

[0016] In a second aspect, an embodiment of the present application provides an immersion photoresist, the components of which include a polyacrylate alkali-soluble resin, an organic solvent, a photoacid generator, and the above-mentioned fluorine-containing resin.

[0017] In the above technical scheme, after the immersion photoresist containing the above fluorine-containing resin is spin-coated, the fluorine-containing resin in the components can quickly and evenly gather on the surface of the immersion photoresist. Since the surface energy of the fluorine-containing resin is relatively low, the immersion photoresist has good hydrophobic properties after being cured into a photoresist film. Even if the photoresist film is immersed in water, components such as the photoacid generator in the components are not easy to overflow from the photoresist film; and the fluorine-containing resin in the photoresist film has a small blocking effect on light of 193nm wavelength, so the immersion photoresist containing the above fluorine-containing resin can be used as an immersion photoresist.

[0018] In addition, since both the side groups and terminal groups of the fluorine-containing resin have ester groups, they are also easily stripped in an alkaline developer, which is beneficial for subsequently improving the etching performance of the chip.

[0019] In a possible implementation, the solvent includes at least one of methyl 3-methoxypropionate, propylene glycol, and propylene glycol methyl ether acetate.

[0020] In a possible implementation, the photoacid generator includes at least one of an iodonium salt and a sulfonium salt. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0022] The fluorine-containing resin and immersion photoresist of the embodiments of the present application are described in detail below.

[0023] The fluorine-containing resin provided in the embodiments of the present application contains a capping group shown in the following general structural formula: Where R f1 At least one selected from fluorine, trifluoromethyl, perfluoroethyl, perfluoropropyl, hexafluoroisopropyl, and perfluorobutyl, wherein n is a positive integer not less than 1; and the fluorine-containing resin further comprises a first repeating unit: Wherein R1 is selected from any one of a hydrogen atom, a C1-C5 alkyl group, and a lactone group; R f2 A fluorine-containing group.

[0024] Since there is a weak interaction between molecules of aromatic compounds, such as π-π stacking, this weak interaction can promote the self-aggregation of aromatic compounds; therefore, in the fluorine-containing resin, the end-capping group containing a benzene ring can also promote the uniform stacking and self-aggregation of the fluorine-containing resin molecules. In addition, in the fluorine-containing resin, both the end-capping group and the first repeating unit have fluorine-containing groups, which can well reduce the surface energy of the fluorine-containing resin and make it have good hydrophobic properties.

[0025] Therefore, when the fluorine-containing resin in the embodiment of the present application is used as a component of the immersion photoresist, after the spin coating process, the fluorine-containing resin containing the above-mentioned end-capping group can spontaneously gather on the surface of the immersion photoresist, and after the immersion photoresist is cured into a photoresist film, the fluorine-containing resin will be located on the outermost surface of the photoresist film to form a hydrophobic layer (i.e., EBL) that plays a protective role, which can prevent other components in the immersion photoresist from dissolving in water. Moreover, although aromatic rings such as benzene rings have an obstructive effect on light with a wavelength of about 193nm, in the embodiment of the present application, the benzene ring-containing resin is used as an end-capping group of the fluorine-containing resin, rather than as a main structure or a side group, so the number of benzene rings is effective, and the blocking of light with a wavelength of about 193nm is also limited. When used for immersion photoresist, the sensitivity and resolution of the immersion photoresist are almost not reduced.

[0026] In the fluorine-containing resin of the present embodiment, the fluorine-containing group R in the first repeating unit f2 The R in the end-capping group f1 Cooperate with each other to reduce the surface energy of fluorine-containing resin. f2 It can be any one of a fluorinated hydrocarbon group having 1 to 30 carbon atoms and a functional group containing a hexafluoroisopropanol alkyl group; wherein the fluorinated hydrocarbon group can be a hydrocarbon group in which all hydrogen atoms are replaced by fluorine, for example etc., or a hydrocarbon group in which some hydrogen atoms are replaced by fluorine, for example etc., which can be selected according to the difficulty of synthesis and actual needs; "functional group containing hexafluoroisopropanol alkyl" means that the fluorine-containing group R f2 Contains Specifically, in this embodiment, R f2 Generally, any one of the fluorinated alkyl groups of C1 to C12 is selected, which can reduce the surface energy of the fluorine-containing resin and enhance the etching resistance and stability of the fluorine-containing resin.

[0027] In addition, in the present embodiment, the fluorine-containing resin generally has a second repeating unit Wherein Rx includes any one of an internal lipid group and an acid-sensitive group. The second repeating unit can improve the stability and etching resistance of the fluorine-containing resin, and in the second repeating unit, the type of the Rx group is a common type of side group in the main resin in the immersion photoresist. The fluorine-containing resin containing the second repeating unit not only has enhanced etching resistance and stability, but also can better match with the main resin when forming the immersion photoresist. Specifically, the acid-sensitive group includes

[0028] Any of; the lipid groups include Any of .

[0029] In the embodiment of the present application, the monomer corresponding to the first repeating unit is the first monomer, and the monomer corresponding to the second repeating unit is the second monomer, which can be prepared by a common reaction method in the art, such as by esterification reaction of acyl chloride, carboxylic acid, carboxylic acid ester and alcohol. Specifically, in the embodiment of the present application, it is preferred that acyl chloride and alcohol are esterified, specifically by crotonyl chloride and R f2 -OH is subjected to an esterification reaction under the condition of a catalyst to obtain a first monomer, and crotonyl chloride and Rx-OH are subjected to an esterification reaction under the condition of a catalyst to obtain a second monomer. Those skilled in the art can select appropriate acidic or basic catalysts according to the actual reaction conditions, and determine appropriate specific operating conditions such as reaction solvents, reaction temperatures, and reaction times.

[0030] In addition, in the embodiments of the present application, the molar ratio of the first repeating unit to the second repeating unit in the fluorine-containing resin is generally between 1:3 and 3:1, which is similar to the existing fluorine-containing resin. If the hydrophobicity of the fluorine-containing resin is to be improved, the molar amount of the first repeating unit can be increased; if the etching resistance of the fluorine-containing resin is to be improved, the molar amount of the second repeating unit can be increased. In order to simplify the description, in all embodiments of the present application, the molar ratio of the first repeating unit to the second repeating unit is fixed.

[0031] In addition, the weight average molecular weight of the fluorine-containing resin in the embodiments of the present application is generally between 15,000 and 26,000, and the PDI is generally not greater than 2.5. Both the weight average molecular weight and the PDI are tested by gel permeation chromatography (GPC). If the weight average molecular weight is too small, the amount of the end-capping group will increase, which will have a certain blocking effect on light with a wavelength of about 193 nm; if the weight average molecular weight is too large, the π-π stacking effect of the end-capping group will not be obvious, which will weaken the self-aggregation effect of the fluorine-containing resin to a certain extent. In addition, if the PDI of the fluorine-containing resin is too large, it will not be conducive to increasing the light transmittance and self-aggregation effect of the fluorine-containing resin.

[0032] In addition, the synthesis method of the fluorine-containing resin in the embodiment of the present application is similar to the existing synthesis method, and is obtained by free radical homopolymerization or anionic polymerization reaction using the monomer corresponding to the repeating unit in the fluorine-containing resin as a raw material, and the molar amount of the first repeating unit and the second repeating unit in the fluorine-containing resin is measured by the molar amount of the monomer; if anionic polymerization is adopted, the initiator can use initiators such as n-butyl lithium and sec-butyl lithium; if free radical polymerization is adopted, the initiator can use azo initiators or peroxide initiators, such as azobisisobutyronitrile (AIBN), dimethyl azobisisobutyrate (V601), dibenzoyl peroxide (BPO), etc.; The end-capping agent is a compound corresponding to the end-capping group, such as 2-chloroacetic acid-3,4-difluorophenyl ester, 2-chloroacetic acid-3,4-dimethylphenyl ester, 2-chloroacetic acid phenyl ester, 2-chloroacetic acid-3,4-ditrifluoromethylphenyl ester or other chloroacetic acid phenyl ester compounds substituted with fluorine-containing substituents. The synthesis of the end-capping agent can refer to the synthesis method of commercially available chloroacetic acid phenyl ester, and the phenyl group therein is replaced with the corresponding substituted phenyl group to obtain various derivatives with different structures. For example, the synthesis is carried out by using a method of esterification of chloroacetyl chloride with the corresponding substituted phenol; the solvent used in the polymerization reaction generally uses common solvents such as methanol, γ-butyrolactone, ethyl acetate, acetone, tetrahydrofuran, NMP, etc.

[0033] The embodiment of the present application also provides an immersion photoresist, the components of which include the above-mentioned fluorine-containing resin, polyacrylate alkali-soluble resin, organic solvent, and photoacid generator.

[0034] In immersion photoresist, polyacrylate alkali-soluble resin exists as the main resin, and generally accounts for 5% to 15% of the immersion photoresist by mass. The main resin can determine the line width that the photoresist can achieve at a specific wavelength, and can also determine the basic properties of the photoresist such as adhesion, chemical resistance, and film thickness. Since polyacrylic alkali-soluble resin has good transmittance to light with a wavelength of about 193nm, polyacrylate alkali-soluble resin is used as the main resin in immersion lithography technology and ArF dry lithography technology. As mentioned above in this article, the repeating unit of polyacrylate alkali-soluble resin can refer to the second repeating unit in the fluorine-containing resin. Furthermore, the polyacrylate alkali-soluble resin can be selected from poly(4-hydroxystyrene-co-2-methyl-2-adamantyl methacrylate) [PHS-MAdMA (60 / 40)], poly(5-acryloxy-2,6-norbornyl lactone-co-2-methyl-2-adamantyl methacrylate-co-2-[1',1',1'-trifluoro-2'-(trifluoromethyl)-2'-hydroxy)propyl-3-norbornyl methacrylate) [NBHFA–MAdMA (40 / 15 / 45 )], poly(5-acryloyloxy-2,6-norbornyl lactone-co-2-methyl-2-cyclopentyl methacrylate-co-2-[1',1',1'-trifluoro-2'-(trifluoromethyl)-2'-hydroxy)propyl-3-norbornyl methacrylate) [NBHFA–MCpMA, (40 / 15 / 45)], poly(5-acryloyloxy-2,6-norbornyl lactone-co-2-ethyl-2-cyclopentyl methacrylate-co-2-ethyl-2-adamantyl methacrylate-co- 2-[1',1',1'-trifluoro-2'-(trifluoromethyl)-2'-hydroxy)propyl-3-norbornyl methacrylate) [NBHFA-EcEdMA], poly((1-methylcyclopentyl methacrylate)-co-(2-methyltricyclo[3.3.1.13,7]dec-2-yl methacrylate)-co-(3-(2-hydroxyethoxy)tricyclo[3.3.1.13,7]dec-1-yl methacrylate)-co-(4-oxa-5-oxotricyclo[4.2. 1.03,7] non-2-yl ester)) [Hd-MCpMA], etc.; as an example, the polyacrylate alkali-soluble resin in the examples and comparative examples of the present application is poly(5-acryloxy-2,6-norbornyl lactone-co-methacrylate 2-methyl-2-adamantyl ester-co-methacrylate 2-[1',1',1'-trifluoro-2'-(trifluoromethyl)-2'-hydroxy)propyl-3-norbornyl ester) [NBHFA-MAdMA (40 / 15 / 45)], with a structure of

[0035] The photoacid generator generates acid under light exposure, which can cause the side groups of the main resin and the fluorine-containing resin to fall off, thereby changing the solubility of the main resin and the fluorine-containing resin. In immersion photoresists, the solubility of the resin is usually increased (this is generally called a positive photoresist). In the embodiment of the present application, the photoacid generator includes at least one of an iodonium salt and a sulfonium salt. Both iodonium salts and sulfonium salts are ionic compounds. The cationic part of the iodonium salt can be selected The anion of the iodonium salt can be selected from The cation portion of the sulfonium salt may be selected from The anion of the sulfonium salt can be selected from

[0036]

[0037] As an example, the photoacid generator in the examples and comparative examples of the present application is a sulfonium salt, specifically:

[0038] As the substance with the largest mass proportion in the immersion photoresist, the organic solvent plays the role of dissolving other components, which facilitates the later spin coating and curing of the immersion photoresist into a photoresist film of suitable thickness, but it itself does not participate in the reaction during the photolithography process. The organic solvent includes at least one of methyl 3-methoxypropionate, propylene glycol, and propylene glycol methyl ether acetate; specifically, in the embodiment of the present application, the organic solvent uses propylene glycol methyl ether acetate.

[0039] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0040] Preparation of monomers:

[0041] Under nitrogen, trifluoroethanol and crotonyl chloride were added to a flask and the nitrogen was replaced. Anhydrous THF was added as a solvent. After stirring and dissolving, a catalytic amount of triethylamine was added. The reaction was carried out at room temperature. After concentration, extraction and column chromatography, the product trifluoroethyl butenoate was obtained with a yield of 48% (ESI-MS m / z: 169.05 [M+H] +, 1H NMR (400 MHz, DMSO-d6) δ 6.29 (m, 1H), 5.53 (m, 1H), 4.67 (dd, 2H), 2.32 (t, 3H).

[0042] 2-Ethyl-2-adamantylmethanol and 3-trifluoromethyl-4,4,4-trifluorobutanol were used to replace trifluoroethanol in the above reaction step and react with crotonyl chloride, and the products 2-ethyl-2-adamantylmethyl butyl ester (ESI-MS m / z: 263.20 [M+H]+) and 3-trifluoromethyl-4,4,4-trifluorobutyl butyl ester (ESI-MS m / z: 265.07 [M+H]+) were obtained after post-treatment.

[0043] Preparation of capping agent:

[0044] Preparation of 3,4-difluorophenyl 2-chloroacetate:

[0045] 3,4-Difluorophenol (130 mg, 1 mmoL) and chloroacetyl chloride (124 mg, 1.1 mmoL) were dissolved in 10 mL of dichloromethane, and pyridine (237 mg, 3 mmoL) was added under ice bath. The ice bath was then removed and stirred for 3 hours. The solvent was evaporated and the residue was purified by silica gel column chromatography to obtain 161 mg of the product 2-chloroacetic acid-3,4-difluorophenyl ester with a yield of 78.5%. 1 H NMR (400MHz, DMSO-d6) δ7.29(m,1H),7.18(m,1H),6.94(m,1H),4.54(s,2H). _

[0046] Preparation of 2-chloroacetic acid-3,4-ditrifluoromethylphenyl ester:

[0047] Referring to the preparation process of 2-chloroacetic acid-3,4-difluorophenyl ester, the difference is that 3,4-difluorophenol is replaced by 3,4-ditrifluoromethylphenol, and the yield is 82.7%. 1 H NMR (400MHz, DMSO-d6) δ7.40(d,1H),7.26(s,1H),7.09(d,1H),4.52(s,2H).

[0048] Preparation of 3,4-dimethylphenyl 2-chloroacetate:

[0049] Referring to the preparation process of 2-chloroacetic acid-3,4-difluorophenyl ester, the difference is that 3,4-difluorophenol is replaced by 3,4-dimethylphenol, and the yield is 91.2%. 1 H NMR (400MHz, DMSO-d6) δ7.21(m,1H), 6.97-7.03(m,2H), 4.54(s,2H), 2.18-2.20(d,4H).

[0050] Preparation of 1-(2-chloroethoxy)-3,4-difluorobenzene:

[0051] In a 25 mL flask, add 3,4-difluorophenol (130 mg, 1.0 mmol), 1-bromo-2-chloroethane (280 mg, 3.0 mmol), K2CO3 (420 mg, 3 mmol) and 10 mL of acetonitrile, reflux reaction, after TLC detection completion of the reaction, cool to room temperature, concentrate, and separate by column chromatography to obtain 152 mg of product, with a yield of 79%. 1 H NMR (400MHz, DMSO-d6) δ7.15(m,1H),7.08(m,1H),6.85(m,1H),4.22(m,2H),4.08(m,2H).

[0052] Example 1

[0053] This embodiment provides a fluorine-containing resin, and the specific preparation method thereof is as follows:

[0054] Under a dry nitrogen flow, a first monomer trifluoroethyl crotonate (7.56 g, 0.045 mol), a second monomer 2-ethyl-2-adamantyl methyl crotonate (13.6 g, 0.055 mol) and 2.1 g of 2-chloroacetic acid-3,4-difluorophenyl ester as a capping agent were added to a 500 mL four-necked reaction flask, and the vacuum was evacuated and replaced with nitrogen three times. 200 mL of methanol was added, and the reaction solution was stirred and mixed in a sealed manner and cooled to 0°C. The initiator V601 (dimethyl azobisisobutyrate, 0.2 g) was dissolved in 100 mL of methanol and slowly added to the reaction system. After stirring for 15 min, the temperature was raised to reflux. The reaction was terminated after 16 h to obtain a polymer solution, which was added dropwise to deionized water to precipitate the polymer. The precipitate was collected, washed and dried to obtain 18.6 g of white powder, which was analyzed by gel permeation chromatography (Gel Permeation Chromatography, GPC) test, its weight average molecular weight is 25360, PDI is 1.6, and the structural formula is as follows:

[0055]

[0056] Example 2

[0057] The preparation method is the same as that of Example 1, except that the end-capping agent is 2-chloroacetic acid-3,4-ditrifluoromethylphenyl ester, and the weight average molecular weight thereof is 25560 and the PDI is 1.7 as determined by GPC. The structural formula is shown below:

[0058]

[0059] Example 3

[0060] The preparation method is the same as that of Example 1, except that the first monomer is 3-trifluoromethyl-4,4,4-trifluorobutyl crotonate. The weight average molecular weight is 29880 and the PDI is 1.6 as determined by GPC. The structural formula is as follows:

[0061]

[0062] Comparative Example 1

[0063] The preparation method is the same as that of Example 1, except that the end-capping agent is phenyl chloroacetate, and the weight average molecular weight thereof is 25280 and the PDI is 1.6 as determined by GPC. The structural formula is shown below:

[0064]

[0065] Comparative Example 2

[0066] The preparation method is the same as that of Example 1, except that the end-capping agent is 3,4-dimethylphenyl chloroacetate, and the weight average molecular weight thereof is 25340 and the PDI is 1.6 as determined by GPC. The structural formula is shown below:

[0067]

[0068] Comparative Example 3

[0069] The preparation method is the same as that of Example 1, except that the end-capping agent is chlorotrifluoroethane. The weight average molecular weight is 25180 and the PDI is 1.6 as determined by GPC. The structural formula is as follows:

[0070]

[0071] Comparative Example 4

[0072] The preparation method is the same as that of Example 1, except that no end-capping agent is added. The weight average molecular weight is 25,000 and the PDI is 1.6 as determined by GPC. The structural formula is shown below:

[0073]

[0074] Comparative Example 5

[0075] The preparation method is the same as that of Example 1, except that the end-capping agent is 1-(2-chloroethoxy)-3,4-difluorobenzene, and its weight average molecular weight is 25330 and PDI is 1.6 as determined by GPC. The structural formula is as follows: 2-Chlorophenyl ethyl ether

[0076]

[0077] Application Examples

[0078] The fluorine-containing resins in the embodiments and comparative examples are used to prepare immersion photoresists, respectively. The components of the immersion photoresist include, by weight, 85 parts of propylene glycol methyl ether acetate, 13 parts of polyacrylate alkali-soluble resin, poly(5-acryloxy-2,6-norbornyl lactone-co-methacrylate 2-methyl-2-adamantyl ester-co-methacrylate 2-[1',1',1'-trifluoro-2'-(trifluoromethyl)-2'-hydroxy)propyl-3-norbornyl ester) [NBHFA-MAdMA (40 / 15 / 45)], and the structure is 2 parts of photoacid generator 1 part of fluorine-containing resin.

[0079] Dynamic water contact angle test

[0080] The immersion photoresist was spin-coated on the surface of the silicon wafer using a spin coater, and then dried to solidify the immersion photoresist into a 110 nm photoresist film. The dynamic water contact angle of the immersion photoresist prepared with the fluorine-containing resin in each embodiment and comparative example was then measured using a dynamic contact angle meter.

[0081] Development defect test

[0082] After measuring the dynamic water contact angle, the immersion photoresist is exposed using immersion lithography, and then developed for 10 seconds using a developer (6.71wt% tetramethylammonium hydroxide aqueous solution), and then rinsed with pure water to form an anti-etching pattern on the mask. Then a scanning electron microscope is used to detect the number of defects on the wafer surface. When the total number of defects is less than 100 / wafer, it is evaluated as A (good), when the total number of defects is 100-500 / wafer, it is evaluated as B (general), and when the total number of defects is greater than 500 / wafer, it is evaluated as C (poor).

[0083] The test results of dynamic water contact angle and development defects are shown in the following table:

[0084] Table 1 Test results of dynamic contact angle and development defects

[0085]

[0086]

[0087] It can be seen from the table that the fluorine-containing resin in the embodiment of the present application has good self-aggregation and hydrophobic properties. When used for immersion photoresist, it can effectively limit the effective components of the cured photoresist film from being dissolved in water; and the fluorine-containing resin in the embodiment of the present application is also easy to strip off and remove in the developer, and will not affect subsequent etching.

[0088] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A fluorine-containing resin, characterized in that: It has a capping group, and the general structural formula of the capping group is: Where R f1 At least one selected from fluorine, trifluoromethyl, perfluoroethyl, perfluoropropyl, hexafluoroisopropyl, and perfluorobutyl, wherein n is a positive integer not less than 1: and the fluorine-containing resin contains the first repeating unit shown below: Wherein R1 is selected from any one of a hydrogen atom, a C1-C5 alkyl group, and a lactone group; R f2 A fluorine-containing group.

2. The fluorine-containing resin according to claim 1, characterized in that R f2 The present invention includes any one of a fluorinated hydrocarbon group having 1 to 30 carbon atoms and a functional group containing a hexafluoroisopropanol alkyl group.

3. The fluorine-containing resin according to claim 1, characterized in that R f2 It is any one of C1-C12 fluoroalkyl groups.

4. The fluorine-containing resin according to claim 1, characterized in that The fluorine-containing resin further contains the second repeating unit shown below: Wherein Rx includes any one of a lactone group and an acid-sensitive group.

5. The fluorine-containing resin according to claim 4, characterized in that The acid-sensitive group includes Any one of; and / or, the inner lipid group includes Any of .

6. The fluorine-containing resin according to claim 1 or 4, characterized in that The weight average molecular weight of the fluorine-containing resin is 20,000 to 26,000; And / or, the polymer dispersibility index of the fluorine-containing resin is not greater than 2.

5.

7. An immersion photoresist, characterized in that: The components include polyacrylate alkali-soluble resin, organic solvent, photoacid generator and the fluorine-containing resin described in claim 1.

8. The immersion photoresist according to claim 7, characterized in that The solvent includes at least one of methyl 3-methoxypropionate, propylene glycol, and propylene glycol methyl ether acetate.

9. The immersion photoresist according to claim 7, characterized in that: The photoacid generator includes at least one of iodonium salt and sulfonium salt.

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