Poly (m-fluorostyrene) sulfonium salt and photoresist composition thereof

Abstract

The invention provides a poly (m-fluorostyrene) sulfonium salt with a repetitive unit as shown in a formula (I) and a photoresist composition of the poly (m-fluorostyrene) sulfonium salt. The photoresist material has good solubility in various polar solvents, and is suitable for being prepared into a thin film. According to the photoresist, the sensitivity of the photoresist is improved by increasing the content of the fluorine element; the sulfonium salt polymer itself contains an acid-sensitive group, does not need to add an additional acid generator, can effectively avoid the problem of acid diffusion in a chemical amplification photoresist, can be directly used as a photoresist main body material, and can be used as a single-component photoresist system for different types of photoetching. Or can be used as an acid generator to be mixed with an acid-sensitive main body material to be used as a photoresist material. By changing the structure of the sulfonium salt, the sulfonium salt has long absorption wavelength, and can also be used for ultraviolet lithography and deep ultraviolet lithography. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the technical field of materials, and particularly relates to a class of poly(m-fluorostyrene) sulfonium salts and their photoresist compositions. Background Art

[0002] With the rapid development of the chip industry, the integration of chips is getting higher and higher, the required resolution for lithography technology is also getting higher, and higher requirements are put forward for the quality of high-resolution patterns, especially for the line edge roughness (LER) and line width roughness (LWR) of patterns. Photoresist is an important basic material in the development of microelectronics technology. The photoresist is coated on the wafer, and after high-energy radiation such as ultraviolet light, electron beam, X-ray, and extreme ultraviolet light, a chemical reaction occurs, the solubility changes, and then the corresponding pattern is transferred to the wafer through the development and etching processes. The resolution of the pattern formed by the photoresist has a decisive influence on the chip integration, so the comprehensive performance of the photoresist should match the development of lithography technology.

[0003] Traditional photoresists are usually chemically amplified photoresists, which are multi-component photoresists, and their formulations are usually composed of a main material, an acid generator, an acid diffusion inhibitor, and other additives. In the photoresist film, the components are randomly distributed, which leads to uneven distribution of the acid generated after exposure in each part of the photoresist. At the same time, there is also the problem of acid diffusion during the post-baking process. The uneven distribution of acid and the problem of acid diffusion make the deprotection reaction uncontrollable, thereby affecting the resolution and pattern quality of lithography. Therefore, although it has the advantage of high sensitivity, it has disadvantages such as uneven component distribution and acid diffusion, which limit the improvement of the resolution of chemically amplified photoresists.

[0004] In contrast, non-chemically amplified photoresists usually have a single component, do not have the problem of acid diffusion, can well avoid the problem of uneven components, and overcome the problem of deteriorated pattern quality caused by acid diffusion. However, the sensitivity of non-chemically amplified photoresists is relatively low. Patent document 202111407329.6 discloses a class of polystyrene sulfonium salt photoresists, which are single-component photoresists. Among them, PSTS has good resolution and pattern quality, but its sensitivity is relatively low, and there is still much room for performance improvement. Summary of the Invention

[0005] To improve the above technical problems, the present invention first provides a sulfonium salt polymer of m-fluorostyrene, and the repeating unit of the polymer has the structure shown in the following formula (I):

[0006]

[0007] Wherein: x and y represent the molar content percentages of two repeating units in the polymer, x + y = 1, 0.3 < x ≤ 1, x is, for example, 0.5, 0.6, 0.7 or 0.8; y is, for example, 0.5, 0.4, 0.3 or 0.2;

[0008] R1 is selected from sulfonium salt groups; the position of R1 can be para, meta or ortho;

[0009] R2 is selected from H, OH, halogen, C 1-15 alkyl, C 1-15 alkoxy, C 6-20 aryl; q is an integer selected from 1 - 4, preferably an integer from 1 - 3;

[0010] X – is an anion, for example selected from halide ions, alkyl sulfonates, haloalkyl sulfonates (such as trifluoromethanesulfonate, perfluoropropyl sulfonate, perfluorobutyl sulfonate), p-toluenesulfonate, tetrafluoroborate, hexafluorophosphate, bis(trifluoromethanesulfonyl)imide ion.

[0011] According to an embodiment of the present invention, the polymer is a random copolymer.

[0012] According to an embodiment of the present invention, the R1 is a sulfonium salt group - S + R3R4, wherein R3 and R4 are the same or different and are independently selected from C 1-15 alkyl, deuterated C 1-15 alkyl (such as deuterated methyl), C 6-20 aryl, or R3, R4 and the S to which they are attached together form a 5 - 8 membered sulfur-containing heterocyclic group, and the sulfur-containing heterocyclic group may optionally further contain 1 - 2 oxygen or sulfur atoms, and the sulfur-containing heterocyclic group may optionally be fused with one or two benzene rings; the C 1-15 alkyl, deuterated C 1-15 alkyl, C 6-20 aryl, 5 - 8 membered sulfur-containing heterocyclic group may be substituted by one, two or more (such as 1 - 5) R1', and R1' may be the same or different and are independently selected from H, oxo, nitro, CN, C 1-15 alkyl or C 1-15 alkoxy.

[0013] According to an embodiment of the present invention, in the sulfonium salt group - S + R3R4, R3 and R4 are the same or different and are independently selected from C 1-6 alkyl, deuterated C 1-6 alkyl, C 6-14 aryl, or R3, R4 and the S to which they are attached together form a 5 - 6 membered sulfur-containing heterocyclic group, and the sulfur-containing heterocyclic group may optionally further contain 1 - 2 oxygen or sulfur atoms, and the sulfur-containing heterocyclic group may optionally be fused with one or two benzene rings;

[0014] The said C 1-6 alkyl, deuterated C 1-6 alkyl, C 6-14 aryl, 5 - 8 - membered sulfur - containing heterocyclic group is optionally substituted by one, two or more R1'; each R1' is the same or different and independently selected from H, oxo, nitro, CN, C 1-6 alkyl or C 1-6 alkoxy.

[0015] According to an embodiment of the present invention, R1 is selected from the following groups which are unsubstituted or optionally substituted by one, two or more R1':

[0016]

[0017] Wherein, represents the bonding connection of the substituent to the benzene ring in the main structure; R 1a and R 1b can be the same or different and are each independently selected from C 1-15 alkyl, deuterated C 1-15 alkyl, phenyl which is unsubstituted or substituted by one, two or more R d ; each R d is the same or different and independently selected from H, = O, nitro, C 1-15 alkyl or C 1-15 alkoxy; m can be selected from integers from 0 to 5; Y is selected from C, O, S or C(O);

[0018] According to an embodiment of the present invention, R1 can be selected from the following groups which are unsubstituted or optionally substituted by one, two or more R1':

[0019]

[0020] Wherein, R 1a and R 1b can be the same or different and are each independently selected from methyl, ethyl, propyl, isopropyl, butyl, deuterated methyl, R d can be selected from H, nitro, ethoxy, ethyl, propyl, butyl, isopropyl, isobutyl; m can be 1 or 2; R1' can be the same or different and independently selected from H, nitro, ethoxy, methyl, ethyl, propyl, butyl, isopropyl or isobutyl.

[0021] As an example, the polymer has a repeating unit as shown below:

[0022]

[0023] Wherein, x and y have the definitions as described above.

[0024] According to an embodiment of the present invention, the molecular weight of the polymer is 500 - 200,000 Daltons, for example, 1000 - 100,000 Daltons, and still for example, 5000 - 50,000 Daltons.

[0025] The present invention also provides a method for preparing the polymer as described above, including the following steps: reacting a polymer with a repeating unit shown in formula (II) with a sulfoxide compound O=R1 in the presence of HX or an acid anhydride of X to obtain a polymer with a repeating unit shown in formula (I):

[0026]

[0027] Wherein, X, x, y, q, R1, and R2 are defined as above.

[0028] Optionally, ion-exchange the polymer with a repeating unit shown in formula (I) with a corresponding anion solution to obtain a poly(m-fluorostyrene) sulfonium salt with a different anion.

[0029] According to an embodiment of the present invention, the sulfoxide compound O=R1 can be R3-SO-R4, for example, selected from the following:

[0030]

[0031] Wherein, R3, R4, R 1a 、R 1b 、Y, and m have the definitions described above.

[0032] According to an embodiment of the present invention, the reaction can be carried out under the action of a catalyst. The acid anhydride of X can be trifluoromethanesulfonic anhydride; the HX is trifluoromethanesulfonic acid.

[0033] According to an embodiment of the present invention, the molar ratio of the polymer shown in formula (II) to the sulfoxide compound O=R1 can be 1:(0.3 - 2), for example, 1:(0.5 - 1), and exemplarily 1:0.8.

[0034] According to an embodiment of the present invention, react the polymer shown in formula (II) with R3-SO-R4 to obtain a polymer with a repeating unit shown in formula (I);

[0035] According to an embodiment of the present invention, when R2 is not H, the polymer with the structure shown in formula (II) is prepared by the following method, including: polymerizing m-fluorostyrene and a compound shown in formula (III) in a certain proportion to obtain a polymer with a repeating unit shown in formula (II),

[0036]

[0037] Wherein, x, y, q, and R2 are as defined above.

[0038] The present invention also provides an application of the polymer represented by the above formula (I) as a photoacid generator or a photo-resist matrix material of a photoresist.

[0039] According to an embodiment of the present invention, when the polymer is used as a photoacid generator of a photoresist, it can be mixed with other photo-resist matrix materials; the other photo-resist matrix materials can be any acid-sensitive photo-resist matrix materials.

[0040] The present invention also provides a photoresist composition, which comprises a polymer having a repeating unit represented by formula (I).

[0041] According to the present invention, the photoresist composition further contains a solvent, and the solvent is, for example, selected from one or more of the following substances: cyclohexanone, ethyl n-pentanone, ethyl isopentanone, ethanol, acetonitrile, isopropanol, or acetone.

[0042] According to the present invention, the photoresist composition comprises a polymer having a repeating unit represented by formula (I), a polymer having an acid-sensitive functional group, and a photoresist solvent.

[0043] According to the present invention, the photoresist composition is a single-component photoresist, and the single-component photoresist is composed of a polymer having a repeating unit represented by formula (I) and a photoresist solvent. It does not contain other compounds or polymers having acid-sensitive functional groups.

[0044] According to an embodiment of the present invention, in the single-component photoresist, the value of x of the repeating unit represented by formula (I) in the polymer is 0.5 or more.

[0045] According to an embodiment of the present invention, in the single-component photoresist, the content of the polymer is 1% - 50% of the total mass of the single-component photoresist, for example, 2% - 10%, and the rest is a photoresist solvent.

[0046] The present invention also provides a photoresist coating, which comprises a polymer having a repeating unit represented by formula (I).

[0047] The present invention also provides a method for preparing the photoresist coating, which includes spin-coating the photoresist composition on a substrate to form a film, thereby obtaining the photoresist coating.

[0048] According to an embodiment of the present invention, the substrate can be a silicon wafer or the like.

[0049] The present invention also provides an application of the photoresist coating in lithography.

[0050] According to an embodiment of the present invention, the photoresist coating is used in modern lithography technologies such as 254 nm lithography, 248 nm lithography, 193 nm lithography, extreme ultraviolet lithography, nanoimprint lithography, or electron beam lithography; it is particularly suitable for high-resolution lithography technologies such as 193 nm, electron beam lithography, and extreme ultraviolet (EUV).

[0051] Due to the presence of a large number of polar functional groups in the polymer of the present invention, it can be dissolved in polar solvents. When the polymer film is exposed to light, the polar sulfonium salt functional groups decompose, reducing the polarity of the polymer, thereby generating a solubility difference. If a solvent with a relatively large polarity is selected for development, the polymer can be used as a negative photoresist; if a solvent with a relatively small polarity is selected for development, the polymer can be used as a positive photoresist.

[0052] Advantageous Effects

[0053] The present invention provides a m-fluorostyrene sulfonium salt polymer represented by formula (I), which contains a photosensitive group sulfonium salt and can be used as an acid generator or a matrix material in a photoresist. Under light irradiation, the sulfonium salt in the polymer decomposes to generate acid, so it can be used as an acid generator. At the same time, the sulfonium salt in the polymer decomposes under light irradiation to form sulfide, thereby causing a large change in its solubility. Therefore, it can also be directly used as the matrix material in the photoresist for development. When it is used as the matrix material, no additional acid generator needs to be added to the photoresist, effectively avoiding the problem of acid diffusion in chemically amplified photoresists. The patterns obtained by lithography of the photoresist of the present invention have high resolution and low line width roughness.

[0054] Since the F element is introduced into the polymer of the present invention, the absorption of extreme ultraviolet light is improved, thereby enhancing the sensitivity of lithography. Moreover, due to the presence of the F element, the hydrophilicity and hydrophobicity of the polymer can be adjusted, thus improving the adhesion between the film and the silicon wafer. In addition, meta-fluorinated styrene can increase the structural asymmetry, thereby improving the solubility and film-forming property of the polymer. Brief Description of the Drawings

[0055] Figure 1 It is an AFM image of the polymer (1) film in Example 2 of the present invention.

[0056] Figure 2 It is a thermogravimetric curve of the polymer (1) in Example 2 of the present invention.

[0057] Figure 3 It is an ultraviolet exposure pattern of the photoresist containing the polymer (1) in Example 7 of the present invention.

[0058] Figure 4 It is an electron beam exposure pattern of the photoresist containing the polymer (1) in Example 8 of the present invention.

[0059] Figure 5 The extreme ultraviolet exposure pattern of the photoresist containing polymer (1) in Example 9 of the present invention.

[0060] Figure 6 The AFM image of the polymer (2) film in Example 3 of the present invention.

[0061] Figure 7 The thermogravimetric curve of the polymer (2) in Example 3 of the present invention.

[0062] Figure 8 The ultraviolet exposure pattern of the photoresist containing polymer (2) in Example 12 of the present invention.

[0063] Figure 9 The AFM image of the polymer (3) film in Example 4 of the present invention.

[0064] Figure 10 The electron beam exposure pattern of the photoresist containing polymer (3) in Example 14 of the present invention.

[0065] Term Definitions and Explanations

[0066] Unless otherwise defined, all scientific and technical terms herein have the same meanings as those commonly understood by those skilled in the art to which the claimed subject matter pertains.

[0067] "More than" means three or more.

[0068] The term "halogen" includes F, Cl, Br, or I.

[0069] The term "C 1-15 alkyl" should be understood to mean a straight-chain or branched-chain saturated monovalent hydrocarbon group having 1 to 15 carbon atoms. For example, "C 1-6 alkyl" represents straight-chain and branched-chain alkyl groups having 1, 2, 3, 4, 5, or 6 carbon atoms. The alkyl groups are, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, neopentyl, 1,1-dimethylpropyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl, 1-ethylbutyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl, 2,3-dimethylbutyl, 1,3-dimethylbutyl, or 1,2-dimethylbutyl, etc., or their isomers.

[0070] The term "C 1-15 alkoxy" should be understood as -O-C 1-15 alkyl, where C 1-15 alkyl has the above definition.

[0071] The term "C 6-20 aryl" should be understood to mean an aromatic monocyclic, bicyclic or tricyclic hydrocarbon ring having 6 to 20 carbon atoms ("C 6-14 aryl"), in particular a ring having 6 carbon atoms ("C6 aryl"), such as phenyl; or biphenyl, or a ring having 9 carbon atoms ("C9 aryl"), such as indanyl or indenyl, or a ring having 10 carbon atoms ("C 10 aryl"), such as tetrahydronaphthyl, dihydronaphthyl or naphthyl, or a ring having 13 carbon atoms ("C 13 aryl"), such as fluorenyl, or a ring having 14 carbon atoms ("C 14 aryl"), such as anthryl. When the C 6-20 aryl is substituted, it can be mono-substituted or multi-substituted. And there is no restriction on the substitution site, for example, it can be ortho-substituted, para-substituted or meta-substituted. Detailed Description of the Invention

[0072] The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only for illustrative explanation of the present invention and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection of the present invention.

[0073] Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.

[0074] Example 1

[0075] Prepare poly(m-fluorostyrene), and the synthesis route is as follows:

[0076]

[0077] Specific steps: In a 500 ml three-necked flask, add m-fluorostyrene (100 ml) and AIBN (2 g), then add THF (200 ml), and bubble for 30 min. React at 70 °C for 24 h, and drop the reaction solution into methanol for precipitation. The obtained product is dried in vacuo. The weight-average molecular weight of the obtained polymer was measured by GPC to be about 10,000 daltons.

[0078] Example 2

[0079] Prepare polymer (1), and the synthesis route is as follows:

[0080]

[0081] Specific steps: Add the poly(m - fluorostyrene) (1 eq) prepared in Example 1 into a 500 ml Schlenk flask, then add the solvent DCM (200 ml) and dibenzo[b,d]thiophene 5 - oxide (0.8 eq). Dropwise add trifluoromethanesulfonic anhydride (2 eq) under an inert gas condition at - 40 °C. Stir at room temperature overnight. After dissolving the product in acetonitrile, drop it into ether for precipitation, and dry it under vacuum to obtain the final product. Confirmed by NMR, the mole content percentage x is 0.8 and y is 0.2. 1 H NMR(400MHz,CD3CN)δ(ppm)7.3 - 7.8(m,9.6H),0.9 - 1.8(s,3H). The molecular weight is 37000 Daltons.

[0082] Example 3

[0083] Prepare polymer (2), and the synthetic route is as follows:

[0084]

[0085] Specific steps: Add the poly(m - fluorostyrene) (1 eq) prepared in Example 1 into a 500 ml Schlenk flask, then add the solvent DCM (200 ml) and tetrahydrothiophene 1 - oxide (0.7 eq). Dropwise add trifluoromethanesulfonic anhydride (2 eq) under an inert gas condition at - 40 °C. Stir at room temperature overnight. After dissolving the product in acetonitrile, drop it into ether for precipitation, and dry it under vacuum to obtain the final product. Confirmed by NMR, the mole content percentage x is 0.7 and y is 0.3. 1 H NMR(400MHz,CD3CN)δ(ppm)7.4 - 7.8(m,3H),1.0 - 1.9(s,8.6H). The molecular weight is 22000 Daltons.

[0086] Example 4

[0087] Prepare polymer (3), and the synthetic route is as follows:

[0088]

[0089] Specific steps: Add the poly(m - fluorostyrene) (1 eq) prepared in Example 1 into a 500 ml Schlenk flask, then add the solvent DCM (200 ml) and methylphenyl sulfoxide (0.6 eq). Dropwise add trifluoromethanesulfonic anhydride (2 eq) under an inert gas condition at - 40 °C. Stir at room temperature overnight. After dissolving the product in acetonitrile, drop it into ether for precipitation, and dry it under vacuum to obtain the final product. Confirmed by NMR, the mole content percentage x is 0.6 and y is 0.4. 11H NMR (400 MHz, CD3CN) δ (ppm) 7.3 - 7.9 (m, 5.3H), 0.9 - 2.1 (s, 4H). The molecular weight is 21,000 Daltons.

[0090] Example 5

[0091] The polymer (1) in Example 2 was dissolved in acetonitrile to prepare a 30 mg / ml solution, which was filtered through a microporous filter with a pore size of 0.22 μm to obtain a spin-coating solution. A film was formed by spin-coating on a silicon substrate, and the film uniformity was analyzed by AFM. See Appendix Figure 1 , from Figure 1 it can be seen that the obtained film is very uniform and there is no crystallization phenomenon.

[0092] Example 6

[0093] The thermal stability of the polymer (1) prepared in Example 2 was measured. The results showed that its decomposition temperature reached above 250 °C, indicating good thermal stability. See Appendix Figure 2 .

[0094] Example 7

[0095] A negative photoresist formulation and ultraviolet lithography: The polymer (1) in Example 2 was dissolved in acetonitrile to prepare a solution with a mass concentration of 5%. The solution was filtered through a microporous filter with a pore size of 0.22 μm to obtain a spin-coating solution. A film was formed by spin-coating on a silicon substrate and baked at 100 °C for 3 minutes. The prepared film was subjected to an exposure experiment (254 nm) with an exposure time of 1.5 min and developed using acetonitrile, resulting in very clear stripes. See Appendix Figure 3 . The width of the lithography stripes is 0.555 microns.

[0096] Example 8

[0097] A negative photoresist formulation and electron beam lithography: The polymer (1) in Example 2 was dissolved in acetonitrile to prepare a solution with a mass concentration of 5%. The solution was filtered through a microporous filter with a pore size of 0.22 μm to obtain a spin-coating solution. A film was formed by spin-coating on a silicon substrate and baked at 100 °C for 3 minutes. The prepared film was subjected to electron beam exposure and developed using a highly polar developer, resulting in very clear stripes (119 nm). See Appendix Figure 4 .

[0098] Example 9

[0099] Negative Photoresist Formulation and Extreme Ultraviolet Lithography: The polymer (1) of Example 2 was dissolved in acetonitrile to prepare a solution with a mass concentration of 5%, filtered through a microporous filter with a pore size of 0.22 μm to obtain a spin-coating solution, spin-coated on a silicon substrate to form a film, baked at 100 °C for 3 minutes, the prepared film was subjected to extreme ultraviolet exposure, and developed using a highly polar developer to obtain very clear stripes (26 nm), see attachment Figure 5 ; The dose for exposure to form the pattern was 82.9 mJ·cm -2 .

[0100] Under the same conditions as in this example, the film of the polymer in Example 3 of Patent Document 202111407327.7 was subjected to extreme ultraviolet exposure, and the dose for exposure to form a clear pattern was 222 mJ·cm -2 . From the above results, it can be seen that the sensitivity of the polymer of the present invention during the lithography process is significantly improved compared to the polymer disclosed in Patent Document 202111407327.7.

[0101] Example 10

[0102] The polymer (2) in Example 3 was dissolved in acetonitrile to prepare a 20 mg / ml solution, filtered through a microporous filter with a pore size of 0.22 μm to obtain a spin-coating solution, spin-coated on a silicon substrate to form a film, and the film uniformity was analyzed by AFM, see attachment Figure 6 , and it can be seen from the figure that the obtained film is very uniform and there is no crystallization phenomenon.

[0103] Example 11

[0104] The thermal stability of the polymer (2) prepared in Example 3 was measured, and the results showed that its decomposition temperature reached above 260 °C, indicating good thermal stability, see attachment Figure 7 .

[0105] Example 12

[0106] Negative Photoresist Formulation and Ultraviolet Lithography: The polymer (2) of Example 3 was dissolved in acetonitrile to prepare a solution with a mass concentration of 5%, filtered through a microporous filter with a pore size of 0.22 μm to obtain a spin-coating solution, spin-coated on a silicon substrate to form a film, baked at 100 °C for 3 minutes, the prepared film was subjected to an exposure experiment (254 nm), the exposure time was 1 min, and developed using acetonitrile to obtain very clear stripes, see attachment Figure 8 . The width of the lithography stripes was 635 nanometers.

[0107] Example 13

[0108] The polymer (3) in Example 4 was dissolved in acetonitrile to prepare a solution with a concentration of 30 mg / ml. The solution was filtered through a microporous filter with a pore size of 0.22 μm to obtain a spin-coating solution. A film was formed by spin-coating on a silicon substrate, and the film uniformity was analyzed by AFM. See the appendix Figure 9 , and it can be seen from the figure that the obtained film is very uniform and there is no crystallization phenomenon.

[0109] Example 14

[0110] A negative photoresist formulation and electron beam lithography: The polymer (3) in Example 4 was dissolved in acetonitrile to prepare a solution with a mass concentration of 5%. The solution was filtered through a microporous filter with a pore size of 0.22 μm to obtain a spin-coating solution. A film was formed by spin-coating on a silicon substrate and baked at 100 °C for 3 minutes. The prepared film was subjected to electron beam exposure and developed using a highly polar developer to obtain very clear stripes (148 nm). See the appendix Figure 10 .

[0111] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A sulfonium salt polymer of m-fluorostyrene, characterized in that, The repeating unit of the sulfonium salt polymer has the structure shown in the following formula (I); Where: x and y represent the molar content percentages of two repeating units in the polymer, x + y = 1, 0.3 < x ≤ 1; R1 is selected from sulfonium salt groups; the position of R1 is para, meta or ortho; R2 is selected from H, OH, halogen, C 1-15 alkyl, C 1-15 alkoxy or C 6-20 aryl; q is an integer selected from 1 - 4; X – is an anion, such as a halide ion, an alkylsulfonate, a trifluoromethanesulfonate, a perfluoropropylsulfonate, a perfluorobutanesulfonate, a p-toluenesulfonate, a tetrafluoroborate, a hexafluorophosphate, or a bis(trifluoromethanesulfonyl)imide ion.

2. The sulfonium salt polymer according to claim 1, wherein R1 is -S + R3R4, wherein R3 and R4 are the same or different and are independently selected from C 1-15 alkyl, deuterated C 1-15 alkyl, C 6-20 aryl, or R3, R4 and the S to which they are attached together form a 5- to 8-membered sulfur-containing heterocyclic group, which sulfur-containing heterocycle optionally further contains 1 to 2 oxygens or sulfurs, and which sulfur-containing heterocycle is optionally fused to one or two benzene rings; The said C 1-15 alkyl, deuterated C 1-15 alkyl, C 6-20 aryl, 5- to 8-membered sulfur-containing heterocyclic group optionally substituted by one, two or more R1'; each R1' is the same or different and independently selected from H, oxo, nitro, CN, C 1-15 alkyl or C 1-15 alkoxy; Preferably, R3 and R4 are the same or different and independently selected from C 1-6 alkyl, deuterated C 1-6 alkyl, C 6-14 aryl, or R3, R4 and the S atom to which they are attached together form a 5- or 6-membered sulfur-containing heterocyclic group, which sulfur-containing heterocyclic group optionally further contains 1 or 2 oxygen or sulfur atoms, and which sulfur-containing heterocyclic group is optionally fused to one or two benzene rings; The said C 1-6 alkyl, deuterated C 1-6 alkyl, C 6-14 aryl, 5- to 8-membered sulfur-containing heterocyclic group is optionally substituted by one, two or more R1'; each R1' is the same or different and independently selected from H, oxo, nitro, CN, C 1-6 alkyl or C 1-6 alkoxy.

3. The sulfonium salt polymer according to claim 1 or 2, characterized in that, R1 is selected from the following groups which are unsubstituted or optionally substituted by one, two or more R1'; Among them, represents the bonding connection of the substituent to the benzene ring in the main structure; R 1a and R 1b are the same or different and each independently selected from C 1-15 alkyl or deuterated C 1-15 alkyl, unsubstituted or phenyl substituted by one, two or more R d ; each R d is the same or different and independently of one another selected from H, ═O, nitro, C 1-15 alkyl or C 1-15 alkoxy; m is an integer selected from 0 - 5; Y is selected from C, O, S or C(O).

4. The sulfonium salt polymer according to claim 3, wherein R1 is selected from the following groups which are unsubstituted or optionally substituted by one, two or more R1'; R 1a and R 1b are the same or different and each independently selected from methyl, ethyl, propyl, isopropyl, butyl, deuterated methyl, R d is selected from H, nitro, ethoxy, ethyl, propyl, butyl, isopropyl or isobutyl; m is 1 or 2; R1' are the same or different and each independently selected from H, nitro, ethoxy, ethyl, ethyl, propyl, butyl, isopropyl or isobutyl.

5. The sulfonium salt polymer according to claim 1, characterized in that, The repeating unit shown in formula (I) is selected from the following structures: Wherein, x and y have the definitions described in claim 1.

6. The preparation method of the sulfonium salt polymer according to any one of claims 1-5, characterized in that, Comprising the following steps: Reacting a polymer with a repeating unit shown in formula (II) with a sulfoxide compound O=R1 in the presence of HX, or an acid anhydride of X; x, y, q, R1, R2 are defined as in any one of claims 1 - 5.

7. Use of the sulfonium salt polymer according to any one of claims 1 - 5 as a photoacid generator or a photo-resist matrix material for a photo-resist.

8. A photoresist composition, characterized in that, It comprises the sulfonium salt polymer according to any one of claims 1 - 5; Preferably, the photo-resist composition further contains a solvent, and the solvent is, for example, selected from one or more of the following substances: cyclohexanone, ethyl n-pentanone, ethyl iso-pentanone, ethanol, acetonitrile, isopropanol or acetone; Preferably, the photo-resist composition comprises the sulfonium salt polymer according to any one of claims 1 - 5, a polymer having an acid-sensitive functional group and a photo-resist solvent; Preferably, the photo-resist composition is a single-component photo-resist, which is composed of the sulfonium salt polymer according to any one of claims 1 - 5 and a photo-resist solvent; Preferably, in the single-component photo-resist, the value of x in the polymer is above 0.5; Preferably, in the single-component photo-resist, the content of the polymer is 1% - 50% of the total mass of the single-component photo-resist, for example 2% - 10%, and the rest is the photo-resist solvent.

9. A photoresist coating, characterized in that, It comprises the sulfonium salt polymer according to any one of claims 1 - 5.

10. Use of the sulfonium salt polymer according to any one of claims 1 - 5, the photo-resist composition according to claim 8 or the photo-resist coating according to claim 9 in photolithography; The photolithography is 254nm photolithography, 248nm photolithography, 193nm photolithography, extreme ultraviolet lithography, nanoimprint lithography or electron beam lithography.

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