A PHS resin with narrow molecular weight distribution and high light transmittance, its synthesis method and application

Abstract

The present invention discloses a PHS resin with a narrow molecular weight distribution and high light transmittance, its synthesis method and application. The PHS resin provided by the present invention comprises a structural general formula shown in formula (I); the present invention also provides a synthesis method of the PHS resin, which is obtained by anionic copolymerization using monomer A, monomer B, monomer C and monomer D as raw materials. The present invention also provides a photoresist, which comprises a film-forming resin; the film-forming resin comprises the PHS resin. The PHS resin of the present invention has the advantages of a narrow molecular weight distribution, excellent light transmittance, good alkali solubility and high thermal stability, effectively solves the problems of relatively low sensitivity and high residual film rate of existing photoresists, and meets the development needs of the integrated circuit industry.

Description

Technical Field

[0001] The present invention relates to a PHS resin with narrow molecular weight distribution and high light transmittance, its synthesis method and application, and belongs to the field of polymer materials. Background Art

[0002] Photoresist is a key functional material in the lithography process of the large-scale integrated circuit industry. The film-forming resin contained therein is an important component of the photoresist. The chemical and physical properties of the film-forming resin directly affect the use effect of the photoresist in the large-scale integrated circuit industry.

[0003] Generally speaking, the lower the optical density value of the film-forming resin, the better its light transmittance, the more sensitive it is during exposure, and the lower the residual film rate. Therefore, light transmittance (optical density) has become one of the very important reference indexes in the performance evaluation of photoresist resins.

[0004] Polyhydroxystyrene (PHS) resin has become the mainstream film-forming resin for 248 nm photoresist due to its good light transmittance (optical density of 0.22 / μm) at 248 nm, good alkali solubility and excellent etching resistance. However, with the improvement of the integrated circuit density, the processing difficulty gradually increases, and higher requirements are also put forward for the resolution and optical sensitivity of the photoresist. The light transmittance of the existing polyhydroxystyrene (PHS) resin needs to be further improved.

[0005] Chinese Patent Application CN108084331A discloses a bio-based film-forming resin and a photoresist prepared therefrom. The bio-based film-forming resin is prepared by a free radical polymerization reaction and an alcoholysis reaction of a styrene derivative and a cholate derivative. This method improves the light transmittance of the film-forming resin by introducing an acrylate monomer with a cholesteryl structure (polycyclic alkane) into the styrene derivative. However, due to the relatively poor heat resistance of the acrylate monomer, the cholesteryl structure is easily removed, resulting in large fluctuations in the light transmittance of the film-forming resin, seriously affecting the stability of the photoresist. Moreover, the styrene derivative monomer used therein has a strong conjugated structure in the benzene ring, and the electron cloud density is relatively concentrated, and its optical density is 0.71 / μm. Therefore, after copolymerization, it is very easy to cause a problem of decreased light transmittance of the copolymer resin. According to the public record thereof, the light transmittance of the 248 nm photoresist prepared from the film-forming resin obtained by this method is only 0.25 / μm.

[0006] In addition, another important indicator for measuring the quality of a polymer is the PDI (Polymer Dispersity Index), which is used to describe the molecular weight distribution of the polymer. The molecular weight of polymers is usually non-uniform and is essentially a mixture. The average molecular weight is used to describe the molecular weight of polymers, and the average molecular weight can be divided into number-average molecular weight, weight-average molecular weight, and viscosity-average molecular weight. The ratio of the weight-average molecular weight to the number-average molecular weight is called the dispersity index. The larger the PDI, the wider the molecular weight distribution and the worse the quality; the smaller the PDI, the narrower and more uniform the molecular weight distribution and the better the quality.

[0007] However, the existing PHS resins are mainly synthesized by free radical polymerization using p-hydroxystyrene or protected acetoxystyrene as polymerizable monomers. Although the obtained PHS resins have high light transmittance, their PDI is too large (PDI ≥ 1.4) and the purity is not high.

[0008] In view of the above, the present invention is specifically proposed. Summary of the Invention

[0009] The object of the present invention is to provide a novel PHS resin with a narrow molecular weight distribution and excellent light transmittance, as well as its synthesis method and application, effectively solving the problem of relatively low sensitivity of existing photoresists, so as to meet the higher processing requirements of the integrated circuit industry.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] In the first aspect, the present invention provides a PHS resin, which comprises the structural general formula shown in formula (I):

[0012]

[0013] In the formula:

[0014] m, n, p, and q respectively represent the degrees of polymerization of repeating unit A, repeating unit B, repeating unit C, and repeating unit D, where m ≥ 1, n ≥ 1, p ≥ 0 and p / (m + n + p + q) ≤ 20%, q ≥ 0;

[0015] R1 represents H, an alkyl group with 1 - 3 carbon atoms, an alkoxy group with 1 - 3 carbon atoms, or a cycloalkyl group with 3 - 10 carbon atoms; preferably H or propyl.

[0016] R3 represents methyl, ethyl, tert-butyl,

[0017] k represents the number of substituents R1, which is a number between 0 and 5.

[0018] The inventive concept and formation mechanism of the present invention are as follows:

[0019] The research of the present invention has found that the repeating unit A has an alicyclic structure. Compared with the benzene ring, it has no conjugated π bond, and its electron cloud distribution is more uniform. In the full wavelength range, its transmittance cut-off wavelength is lower. Therefore, introducing it into the PHS resin can significantly reduce the optical density of the PHS resin. At the same time, it can also undergo anionic polymerization with the monomer having the repeating unit B, thereby making the molecular weight distribution of the PHS resin narrower.

[0020] In addition, on the basis of the repeating unit A and the repeating unit B, the repeating unit C and the repeating unit D are further introduced to meet the performance requirements of different photoresist film-forming resins. Among them, the repeating unit C plays a role in further improving the heat resistance of the resin, so that the PHS resin further has the performance advantage of high temperature resistance; while the repeating unit D plays a role in improving the adhesion between the film and the substrate, so that the PHS resin further has the performance advantage of high peel strength and better use performance.

[0021] The novel PHS resin obtained by the present invention not only has a lower optical density (<0.2 / μm), but also has a narrower molecular weight distribution (PDI≤1.2), and at the same time has the advantages of good heat resistance and stable structure.

[0022] In formula (I), the ratio of m:(n + p + q)≥0.25; preferably (0.25 - 1):1. Research shows that by reasonably controlling the addition ratio of the cyclohexane monomer, the role of monomer A in reducing the optical density of the PHS resin can be effectively guaranteed. If the addition ratio is too low, the advantages of copolymerization cannot be shown.

[0023] The weight average molecular weight of the PHS resin is between 1000 and 100000, and PDI≤1.2.

[0024] In the second aspect, the present invention provides a method for synthesizing the PHS resin, including the following steps:

[0025] First, use monomer A monomer B monomer C monomer D as raw materials for anionic copolymerization reaction, and then carry out a deprotection reaction on the R2 substituent to obtain the PHS resin;

[0026] The definitions of R1, R3, and k are the same as those in formula (I);

[0027] R2 represents one or more of methyl, ethyl, tert-butyl, propyl, isopropyl, acetoxy, and propionyloxy.

[0028] The anionic copolymerization reaction is carried out in an environment of nitrogen circulation.

[0029] The temperature of the copolymerization reaction is -75 - 80°C.

[0030] The initiator used in the anionic copolymerization reaction is one or more of propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, lithium chloride, sodium naphthalide, sodium and potassium.

[0031] The solvent used in the anionic copolymerization reaction is one or more of benzene, toluene, tetrahydrofuran, ether, isopropyl ether, ethyl ether, n-propyl ether, hexane, cyclohexane, heptane, n-heptane, ethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether and propylene glycol methyl ether acetate.

[0032] The deprotection reaction refers to the elimination of the protecting group R2 to make it H, obtaining the PHS resin; the reagent used in the deprotection reaction is hydrobromic acid or hydrochloric acid.

[0033] In a third aspect, the present invention also provides a photoresist, comprising a film-forming resin; the film-forming resin comprises the above-mentioned PHS resin. Preferably, the photoresist is a 248 nm photoresist.

[0034] Compared with the prior art, the beneficial effects obtained by the present invention are as follows:

[0035] The present invention selects monomer A and monomer B to copolymerize to prepare the PHS resin, which not only significantly reduces the optical density of the polymer resin (<0.2 / μm) by using monomer A with high thermal stability, but also realizes anionic polymerization, thereby significantly reducing the molecular weight distribution (≤1.2), and obtaining a novel PHS resin with excellent light transmittance and narrow molecular weight distribution.

[0036] At the same time, according to actual processing needs, by introducing monomers C and D with different properties, the molecular weight can be between 1000 and 100000, and the solid content can be between 5% and 60% to meet different usage requirements. Specific Embodiments

[0037] The experimental methods used in the following examples are all conventional methods unless otherwise specified.

[0038] The materials, reagents, etc. used in the following examples can be obtained from commercial channels unless otherwise specified.

[0039] Example 1

[0040] This example provides a polymer resin synthesized from vinylcyclohexane monomer A to verify the very low optical density of vinylcyclohexane monomer A.

[0041] The specific synthesis steps are as follows:

[0042] Under a nitrogen atmosphere, 30 g (0.2662 mol) of vinylcyclohexane was added to 270 g of tetrahydrofuran (THF) solvent at -78 °C, and the mixture was stirred for 20 minutes. Then, 4.2 ml (5 mmol) of initiator n-butyllithium solution was added, and the mixture was stirred at -78 °C for 30 minutes;

[0043] Subsequently, 30 g of methanol was added to the obtained reaction mixture to quench the reaction. After the reaction stopped, precipitation was carried out with methanol solvent, and the product was taken out by filtration and dried.

[0044] The obtained vinylcyclohexane polymer was subjected to GPC measurement and optical density test, and the results are shown in Table 1.

[0045] Example 2

[0046] This example provides a target product PHS resin and its synthesis method.

[0047] Synthesis monomers: Monomer A is vinylcyclohexane (k = 0, R1 = H), and monomer B is 4-methoxystyrene (R2 = methyl);

[0048] In the PHS resin, the ratio of the degree of polymerization is m:n = 5:5.

[0049] The specific synthesis steps are as follows:

[0050] Anionic copolymerization: Under a nitrogen atmosphere, 14.7 g (0.1331 mol) of vinylcyclohexane and 17.9 g (0.1331 mol) of 4-methoxystyrene were added to 294 g of tetrahydrofuran (THF) solvent at -78 °C, and the mixture was stirred for 20 minutes. Then, 4.2 ml (5 mmol) of n-butyllithium solution was added, and the mixture was stirred at -78 °C for 30 minutes;

[0051] Subsequently, 30 g of methanol was added to the obtained reaction mixture to quench the reaction. After the reaction stopped, precipitation was carried out with methanol solvent, and the product was taken out by filtration and dried.

[0052] Deprotection: The resin powder was dissolved in 200 g of a mixed solvent of toluene and ethanol with a ratio of 1.6:1. 95 mmol of concentrated hydrochloric acid and 3.05 g of pure water were added, and the mixture was stirred at 90 °C for 3 hours. After cooling to room temperature, 100 mmol of triethylamine was added, and the mixture was stirred for 10 minutes. Then, 100 mmol of acetic acid was added and concentrated. Then, liquid separation was carried out with ethyl acetate and pure water, and the organic phase containing the resin was concentrated and dried under reduced pressure to obtain a resin solid.

[0053] The obtained PHS resin was subjected to GPC measurement and optical density test, and the results are shown in Table 1.

[0054] Example 3

[0055] This embodiment provides a target product PHS resin and its synthesis method.

[0056] Synthesis monomers: Monomer A is vinylcyclohexane (k = 0, R1 = H), and monomer B is 4-methoxystyrene (R2 = methyl).

[0057] In the PHS resin, the ratio of the degree of polymerization is m:n = 2:8.

[0058] The specific synthesis steps are as follows:

[0059] Anionic copolymerization: Under a nitrogen atmosphere, into 310 g of tetrahydrofuran (THF) solvent at -78 °C, then add 5.9 g (0.0532 mol) of vinylcyclohexane and 28.6 g (0.2130 mol) of 4-methoxystyrene, stir for 20 minutes, and then add 4.2 ml (5 mmol) of n-butyllithium solution, and stir at -78 °C for 30 minutes.

[0060] Then add 30 g of methanol to quench the reaction in the resulting reaction mixture. After the reaction stops, perform a precipitation operation with methanol solvent, filter and take out, and dry in air.

[0061] Deprotection: Dissolve the resin powder in 200 g of a mixed solvent of toluene and ethanol at a ratio of 1.6:1, add 95 mmol of concentrated hydrochloric acid and 3.05 g of pure water, stir at 90 °C for 3 hours, cool to room temperature, add triethylamine (100 mmol), stir for 10 minutes, then add acetic acid (100 mmol) and concentrate. Then separate with ethyl acetate and pure water, concentrate the organic phase containing the resin, and obtain a resin solid after drying under reduced pressure.

[0062] Perform GPC measurement and optical density test on the obtained PHS resin, and the results are shown in Table 1.

[0063] Example 4

[0064] This embodiment provides a target product PHS resin and its synthesis method.

[0065] Synthesis monomers: Monomer A is vinylcyclohexane (k = 0, R1 = H), and monomer B is 4-methoxystyrene (R2 = methyl).

[0066] In the PHS resin, the ratio of the degree of polymerization is m:n:p = 2:6:2.

[0067] The specific synthesis steps are as follows:

[0068] Anionic copolymerization: Under a nitrogen atmosphere, into 300 g of tetrahydrofuran (THF) solvent at -78 °C, then add 5.9 g (0.0532 mol) of vinylcyclohexane, 21.5 g (0.1597 mol) of 4-methoxystyrene, and 5.6 g (0.0532 mol) of styrene, stir for 20 minutes, then add 4.2 ml (5 mmol) of n-butyllithium solution, and stir at -78 °C for 30 minutes;

[0069] Next, add 30 g of methanol to quench the resulting reaction mixture to stop the reaction, then perform a precipitation operation with methanol solvent, filter, take out, and dry.

[0070] Deprotection: Dissolve the resin powder in 200 g of a mixed solvent of toluene and ethanol with a ratio of 1.6:1, add 95 mmol of concentrated hydrochloric acid and 3.05 g of pure water, stir at 90 °C for 3 hours, cool to room temperature, add triethylamine (100 mmol), stir for 10 minutes, then add acetic acid (100 mmol) and concentrate. Then separate with ethyl acetate and pure water, concentrate the organic phase containing the resin, and obtain a resin solid after drying under reduced pressure.

[0071] Perform GPC measurement and optical density test on the obtained PHS resin, and the results are shown in Table 1.

[0072] Example 5

[0073] This example provides a target product PHS resin and its synthesis method.

[0074] Synthesis monomers: Monomer A is vinylcyclohexane (k = 0, R1 = H), monomer B is tert-butoxystyrene (R2 = tert-butyl), monomer C is styrene, monomer D is tert-butyl methacrylate (R3 = tert-butyl);

[0075] In the PHS resin, the ratio of the degree of polymerization is m:n:p:q = 2:4:2:2.

[0076] The specific synthesis steps are as follows:

[0077] Anionic polymerization: Under a nitrogen atmosphere, into 342 g of tetrahydrofuran (THF) solvent at -78 °C, then add 5.9 g (0.0533 mol) of vinylcyclohexane, 5.6 g of styrene (0.0533 mol), and 18.8 g (0.1066 mol) of tert-butoxystyrene, stir for 20 minutes, then add 4.2 ml (5 mmol) of n-butyllithium [initiator] solution, and stir at -78 °C for 30 minutes;

[0078] Continue to add 11.1 g (11.3 mmol) of 3.79% lithium chloride initiator / tetrahydrofuran solution to the solution, and add a solution of 7.7 g (0.0533 mol) of tert-butyl methacrylate and 1 ml (1 mmol) of diethylzinc in 20 g of tetrahydrofuran to the reaction solution, and react for 30 minutes;

[0079] Then, add 30 g of methanol to the obtained reaction mixture to quench the reaction. After the reaction stops, perform a precipitation operation with methanol solvent, wash three times with deionized water after filtration, and then take it out and dry it.

[0080] Deprotection: Dissolve the resin powder in 200 g of a mixed solvent of toluene and ethanol at a ratio of 1.6:1, add 60 mmol of concentrated hydrochloric acid and 3.05 g of pure water, stir at 90 °C for 3 hours, cool to room temperature, add triethylamine (70 mmol), stir for 10 minutes, then add acetic acid (70 mmol) and concentrate. Then, separate with ethyl acetate and pure water, concentrate the organic phase containing the resin, and obtain a resin solid after drying under reduced pressure.

[0081] Perform GPC measurement and optical density test on the obtained PHS resin, and the obtained results are shown in Table 1.

[0082] Example 6

[0083] This example provides a target product PHS resin and its synthesis method.

[0084] The difference from Example 2 is: replacing monomer A, specifically 4-propylvinylcyclohexane, R1 = propyl, k = 0.

[0085] Comparative Example 1

[0086] This comparative example provides a polymeric resin synthesized only from styrene.

[0087] Synthesis monomer: styrene;

[0088] The specific synthesis steps are as follows:

[0089] Under a nitrogen atmosphere, add 27.8 g (0.2662 mol) of styrene to 450 g of tetrahydrofuran (THF) solvent at -78 °C, stir for 20 minutes, then add 4.2 ml (5 mmol) of n-butyllithium solution, and stir at -78 °C for 30 minutes;

[0090] Then, add 30 g of methanol to the obtained reaction mixture to quench the reaction. After the reaction stops, perform a precipitation operation with methanol solvent, wash three times with deionized water after filtration, and then take it out and dry it.

[0091] The resulting polymer was subjected to GPC measurement and optical density test, and the obtained results are shown in Table 1.

[0092] Comparative Example 2

[0093] This comparative example provides a PHS resin and its synthesis method.

[0094] Synthesis monomers: 4-methoxystyrene, styrene;

[0095] The specific synthesis steps are as follows:

[0096] Under a nitrogen atmosphere, into 450 g of tetrahydrofuran (THF) solvent at -78 °C, then 17.9 g (0.1331 mol) of 4-methoxystyrene and 13.9 g (0.1331 mol) of styrene were added, stirred for 20 minutes, then 4.2 ml (5 mmol) of n-butyllithium solution was added, stirred at -78 °C for 30 minutes, then 30 g of methanol was added to quench the reaction mixture. After the reaction stopped, precipitation was carried out with methanol solvent, and after filtration and extraction, it was dried.

[0097] The resin powder was dissolved in 200 g of a mixed solvent of toluene and ethanol at a ratio of 1.6:1, 100 mmol of concentrated hydrochloric acid and 3.05 g of pure water were added, stirred at 90 °C for 3 hours, cooled to room temperature, then triethylamine (110 mmol) was added, stirred for 10 minutes, then acetic acid (110 mmol) was added and concentrated. Then, liquid separation was carried out with ethyl acetate and pure water, and the organic phase containing the resin was concentrated and dried under reduced pressure to obtain a resin solid.

[0098] The resulting polymer was subjected to GPC measurement and optical density test, and the obtained results are shown in Table 1.

[0099] Comparative Example 3

[0100] This comparative example provides a polymeric resin synthesized using only tert-butoxystyrene as a monomer raw material.

[0101] Synthesis monomer: tert-butoxystyrene;

[0102] The specific synthesis steps are as follows:

[0103] Under a nitrogen atmosphere, into 500 g of tetrahydrofuran (THF) solvent at -78 °C, then 47.0 g of tert-butoxystyrene was added, stirred for 20 minutes, then 4.2 g (5 mmol) of n-butyllithium solution was added, stirred at -78 °C for 30 minutes;

[0104] Then 30 methanol was added to quench the resulting reaction mixture. After the reaction stopped, precipitation was carried out with methanol solvent, and after filtration and extraction, it was dried.

[0105] Dissolve the resin powder in 200 g of a mixed solvent of toluene and ethanol at a ratio of 1.6:1, add 190 mmol of concentrated hydrochloric acid and 3.05 g of pure water, stir at 90 °C for 3 hours, cool to room temperature, add triethylamine (200 mmol), stir for 10 minutes, then add acetic acid (200 mmol) and concentrate. Then separate the liquid with ethyl acetate and pure water, concentrate the organic phase containing the resin, and obtain a resin solid after drying under reduced pressure.

[0106] Perform GPC measurement on the obtained polymer and calculate the ratio of the input materials to the obtained product. The obtained results are shown in Table 1.

[0107] Comparative Example 4

[0108] This comparative example provides a target product PHS resin and its synthesis method.

[0109] Synthesis monomers: Monomer A is vinylcyclohexane (k = 0, R1 = H), and monomer B is 4-methoxystyrene (R2 = methyl);

[0110] In the PHS resin, the ratio of the degree of polymerization is m:n = 1:9.

[0111] The specific synthesis steps are as follows:

[0112] Anionic copolymerization: Under a nitrogen atmosphere, add 3.0 g (0.0266 mol) of vinylcyclohexane and 32.2 g (0.2396 mol) of 4-methoxystyrene to 317 g of tetrahydrofuran (THF) solvent at -78 °C, stir for 20 minutes, then add 4.2 ml (5 mmol) of n-butyllithium solution, and stir at -78 °C for 30 minutes;

[0113] Then add 30 g of methanol to quench the reaction in the obtained reaction mixture. After the reaction stops, perform a precipitation operation with methanol solvent, filter and take out, and dry in the air.

[0114] Deprotection: Dissolve the resin powder in 200 g of a mixed solvent of toluene and ethanol at a ratio of 1.6:1, add 95 mmol of concentrated hydrochloric acid and 3.05 g of pure water, stir at 90 °C for 3 hours, cool to room temperature, add triethylamine (100 mmol), stir for 10 minutes, then add acetic acid (100 mmol) and concentrate. Then separate the liquid with ethyl acetate and pure water, concentrate the organic phase containing the resin, and obtain a resin solid after drying under reduced pressure.

[0115] Perform GPC measurement and optical density test on the obtained polymer. The obtained results are shown in Table 1.

[0116] Comparative Example 5

[0117] This comparative example provides a target product PHS resin and its synthesis method.

[0118] Synthetic monomers: Monomer A is vinylcyclohexane (k = 0, R1 = H), monomer B is 4-methoxystyrene (R2 = methyl), and monomer C is styrene;

[0119] In the PHS resin, the ratio of the degree of polymerization is m:n:p = 2:5:3 (the degree of polymerization of monomer C styrene exceeds 20%).

[0120] The specific synthesis steps are as follows:

[0121] Anionic copolymerization: Under a nitrogen atmosphere, into 300 g of tetrahydrofuran (THF) solvent at -78 °C, then add 5.9 g (0.0532 mol) of vinylcyclohexane, 17.9 g (0.1331 mol) of 4-methoxystyrene, and 8.4 g (0.0799 mol) of styrene, stir for 20 minutes, then add 4.2 ml (5 mmol) of n-butyllithium solution, and stir at -78 °C for 30 minutes;

[0122] Then add 30 g of methanol to quench the reaction mixture to stop the reaction, perform precipitation operation with methanol solvent, filter and take out, and dry in air.

[0123] Deprotection: Dissolve the resin powder in 200 g of a mixed solvent of toluene and ethanol with a ratio of 1.6:1, add 95 mmol of concentrated hydrochloric acid and 3.05 g of pure water, stir at 90 °C for 3 hours, cool to room temperature, add triethylamine (100 mmol), stir for 10 minutes, then add acetic acid (100 mmol) and concentrate. Then perform liquid separation with ethyl acetate and pure water, concentrate the organic phase containing the resin, and obtain a resin solid after drying under reduced pressure.

[0124] Perform GPC measurement and optical density test on the obtained polymer, and the results are shown in Table 1.

[0125] Effect verification:

[0126] Perform performance tests on the polymerization resins obtained in Examples 1-6 and Comparative Examples 1-5.

[0127] The test methods are as follows:

[0128] Molecular weight: The weight-average molecular weight Mw, number-average molecular weight Mn, and dispersity PDI of the polymer are all measured by gel permeation chromatography. Specifically, the GPC device can be measured using Alliance E2695 of Waters Corporation, and the measurement solvent is tetrahydrofuran.

[0129] Optical density (OD value): It was measured using a UV spectrophotometer of model Cary 4000 from Agilent. The prepared solution was N,N-dimethylformamide with a concentration of 100 ppm. The test formula is as follows:

[0130] D = LgO = Lg(1 / T)

[0131] In the formula, D is the optical density, O is the opacity, and T is the transmittance.

[0132] Taper angle: It was measured using an electron microscope. The angle is the inner inclination angle between the bottom end of the resin and the substrate after exposure and etching. The closer the angle is to 90 degrees, the higher the sensitivity of the surface resin and the lower the residual film rate.

[0133] Table 1 Performance table of the polymeric resins obtained in each example and comparative example

[0134]

[0135] The following conclusions were drawn from the above test results:

[0136] (1) From the test results of Examples 2-6, it can be seen that the PHS resins copolymerized from monomer A and monomer B, as well as the PHS resins obtained by introducing other monomers based on the copolymerization of monomer A and monomer B, all have very low optical density, which can significantly improve the sensitivity and resolution of the photoresist, and solve the problems of low sensitivity and high residual film rate of the existing photoresist, which cannot meet the processing requirements.

[0137] At the same time, the obtained PHS resin also has a narrow molecular weight distribution (PDI controlled within 1.2), which can meet the performance requirements of the film-forming resin for 248 nm photoresist.

[0138] (2) By comparing the test results of Example 1, Example 4, Comparative Example 1, and Comparative Example 2, it can be seen that the optical density of the vinylcyclohexane polymer obtained in Example 1 is only 0.11 / μm, which is much lower than the optical density of the styrene polymers in Comparative Example 1 and Comparative Example 2, indicating that the vinylcyclohexane polymer has excellent transmittance.

[0139] (3) By comparing the test results of Example 2 and Comparative Example 3, it can be seen that the introduction of monomer A can significantly reduce the optical density of the PHS resin, thereby significantly reducing the exposure residual film rate of the photoresist.

[0140] (4) By comparing the test results of Examples 1-3 and Comparative Example 4, it can be seen that by reasonably controlling the ratio of m / n, a PHS resin with better performance can be obtained.

[0141] (5) By comparing the test results of Examples 1-3 and Comparative Example 5, it can be seen that although the degree of polymerization of monomer A is controlled at 20%, the degree of polymerization of styrene in monomer C exceeds 20%, and the optical density of the obtained resin is relatively high, indicating that styrene has an adverse effect on reducing the optical density of the resin. Therefore, the degree of polymerization of styrene in monomer C should be strictly controlled.

[0142] The results show that the photoresist obtained by mixing the PHS resin prepared in Example 1 as the film-forming matrix with conventional additives has higher resolution and optical sensitivity, effectively solving the problems of low sensitivity and high exposure residue rate existing in the existing photoresist; and the obtained photoresist has good stability; thus meeting the higher processing requirements of the integrated circuit industry.

[0143] Although the present invention has been described in detail with general descriptions and specific embodiments above, on the basis of the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A PHS resin, comprising the structural general formula shown in formula (I): In the formula: m, n, p, and q respectively represent the degrees of polymerization of repeating unit A, repeating unit B, repeating unit C, and repeating unit D, where m≥1, n≥1, p≥0 and p / (m + n + p + q)≤20%, q≥0; R1 represents H or an alkyl group of C1-C3; R3 represents methyl, ethyl, or tert-butyl; k represents the number of substituents R1, which is a number between 0 and 5.

2. The PHS resin according to claim 1, wherein: In formula (I), the ratio of m:(n + p + q)≥1 / 4.

3. The PHS resin according to claim 1 or 2, characterized in that: The weight-average molecular weight of the PHS resin is between 1000 and 100000, and PDI≤1.

2.

4. The synthesis method of the PHS resin according to any one of claims 1-3, comprising the following steps: First, using monomer A , monomer B , monomer C and / or monomer D as raw materials to carry out an anionic copolymerization reaction, and then performing a deprotection reaction on the R2 substituent to obtain the PHS resin described in any one of claims 1-3; The definitions of R1, R3, and k are the same as those in formula (I); R2 represents one or more of methyl, ethyl, tert-butyl, propyl, isopropyl, acetoxy, and propionyloxy.

5. The synthesis method according to claim 4, characterized in that: The anionic copolymerization reaction is carried out in an environment of nitrogen circulation.

6. The synthesis method according to claim 4, characterized in that: The temperature of the anionic copolymerization reaction is -75-80°C.

7. The synthesis method according to claim 4, characterized in that: The initiator used in the anionic copolymerization reaction is one or more of propyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, lithium chloride, sodium naphthalene, metallic sodium, and metallic potassium.

8. The synthesis method according to claim 4, characterized in that: The solvent used in the anionic copolymerization reaction is one or more of benzene, toluene, tetrahydrofuran, diethyl ether, isopropyl ether, ethylene glycol dimethyl ether, n-propyl ether, hexane, cyclohexane, heptane, n-heptane, ethyl acetate, propylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol methyl ether acetate.

9. The synthesis method according to claim 4, characterized in that: The reagent used in the deprotection reaction is hydrobromic acid or hydrochloric acid.

10. A photoresist, comprising a film-forming resin; the film-forming resin comprises the PHS resin according to any one of claims 1-3, and its optical density≤0.2 / μm.

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