A mixed resin and method for removing metal impurities from photoresist solutions

Abstract

The application belongs to the technical field of integrated circuit materials, and particularly relates to a mixed resin for removing metal impurities in a photoresist solution and a method thereof. The mixed resin comprises a chelating resin, a modified resin and a macroporous adsorption resin. The method comprises: passing the photoresist solution through a PFA column filled with the mixed resin. The photoresist solution purified by the mixed resin has metal impurities of less than or equal to 15 ppb, and the purified photoresist solution is neutral. The mixed resin and the method are particularly suitable for treating photoresist solutions with acid-labile components, and have wide application prospects and good economic benefits in the field of integrated circuit materials.

Description

Technical Field

[0001] This invention belongs to the field of integrated circuit materials technology, and in particular to the field of photoresist purification technology. Specifically, it relates to a uniform particle mixed resin and method for deep removal of gold impurities from photoresist solutions. Background Technology

[0002] Photoresist solution is a photosensitive mixture composed of photoresist resin, solvent, monomers, and other additives. Metal ion impurities in the photoresist solution can cause short circuits in chip components and unstable chip performance. From upstream basic chemical raw materials to monomer preparation, and then to resin synthesis and photoresist formulation development, each stage of the product requires strict control of metal and impurities. To meet the high-performance requirements of photoresist, metal impurities in the photoresist need to be purified to a very low level.

[0003] Unlike solvents and other single-molecule materials, purifying photoacid generators and photoresist resins is much more difficult. Photoresist resins are composed of molecular chains of varying lengths, with these chains exhibiting a normal distribution, significantly increasing the difficulty of purification. Traditional photoresist purification methods include precipitation separation, distillation, water washing, membrane filtration, and ion exchange resin purification. However, photoresist purified using these methods still suffers from high metal impurity content, high acid residue, high water residue, and low film retention, failing to meet the increasingly stringent precision requirements of semiconductor processes for metal impurities and acid residue. Furthermore, the residual acid in the photoresist solution after traditional purification methods can easily lead to deprotection reactions, thereby damaging the photoresist structure. While water washing can reduce residual acid in the photoresist solution, it increases purification time and cost, and also introduces water impurities.

[0004] Although ion exchange resins are widely used in the purification of photoresist solutions, conventional ion exchange resin columns are limited by ion diffusion and usually have fluid bypass, which leads to insufficient resin utilization and low efficiency in deep removal of metal ions. For gold heteroion concentration requirements at the single ppb or even ppt level, any bypass or inefficient mass transfer and diffusion is not allowed.

[0005] Therefore, there is an urgent need to research and develop a material and method for deeply and efficiently removing metal impurities and residual acids from photoresist solutions without introducing moisture impurities. Summary of the Invention

[0006] To address the problems of difficulty in deeply removing metal impurities and high acid residue in existing photoresist solutions, this invention provides a uniformly sized mixed resin and method for deeply removing metal impurities from photoresist solutions. The uniformly sized mixed resin of this invention can efficiently and deeply remove metal impurities and residual acid from photoresist, while also obtaining a clear and transparent photoresist solution.

[0007] Specifically, one aspect of the present invention provides a mixed resin comprising a chelating resin, a modified resin, and a macroporous adsorption resin; the modified resin is an ion exchange resin containing functional groups of both cation exchange resin and anion exchange resin; the functional groups of the cation exchange resin include functional groups of gel-type cation exchange resin and functional groups of macroporous cation exchange resin; in the modified resin, the molar ratio of the functional groups of the cation exchange resin to the functional groups of the anion exchange resin is 1:1 to 1:5; the mixed resin is spherical particles with an average particle size of 0.4 to 1.2 mm and a uniformity coefficient of 1.05 to 1.95.

[0008] In one or more embodiments, the monomers of the modified resin comprise styrene and divinylbenzene; preferably, the mass ratio of styrene to divinylbenzene is 1:0.10 to 1:0.12.

[0009] In one or more embodiments, the modified resin has a molar fraction of 50% to 90% in the mixed resin.

[0010] In one or more embodiments, the modified resin has a molar fraction of 70% to 90% in the mixed resin.

[0011] In one or more embodiments, the modified resin has a molar fraction of 75% to 85% in the mixed resin.

[0012] In one or more embodiments, the macroporous adsorption resin has a molar fraction of 1% to 30% in the mixed resin.

[0013] In one or more embodiments, the macroporous adsorption resin has a molar fraction of 5% to 20% in the mixed resin.

[0014] In one or more embodiments, the chelating resin has a molar fraction of 1% to 40% in the mixed resin.

[0015] In one or more embodiments, the chelating resin has a molar fraction of 5% to 20% in the mixed resin.

[0016] In one or more embodiments, the molar ratio of the functional groups of the cation exchange resin to the functional groups of the anion exchange resin in the modified resin is 1:1.7 to 1:2.3.

[0017] In one or more embodiments, in the modified resin, the molar ratio of the functional groups of the cation exchange resin to the functional groups of the anion exchange resin is 1:1.7 to 1:1.9.

[0018] In one or more embodiments, the average particle size of the mixed resin is 0.5 to 0.6 mm.

[0019] In one or more embodiments, the uniformity coefficient of the mixed resin is 1.05 to 1.3.

[0020] In one or more embodiments, the uniformity coefficient of the mixed resin is 1.05 to 1.25.

[0021] In one or more embodiments, the uniformity coefficient of the mixed resin is 1.05 to 1.15.

[0022] In one or more embodiments, the molar ratio of the functional groups of the gel-type cation exchange resin to the functional groups of the macroporous cation exchange resin is 4:1 to 1:4.

[0023] In one or more embodiments, the molar ratio of the functional groups of the gel-type cation exchange resin to the functional groups of the macroporous cation exchange resin is 4:1 to 1:1.

[0024] In one or more embodiments, the molar ratio of the functional groups of the gel-type cation exchange resin to the functional groups of the macroporous cation exchange resin is 4:1 to 3:1.

[0025] In one or more embodiments, the functional groups of the gel-type cation exchange resin are the functional groups of a strong acid-type cation exchange resin.

[0026] In one or more embodiments, the functional group of the strong acid cation exchange resin is a sulfonic acid group.

[0027] In one or more embodiments, the functional groups of the macroporous cation exchange resin are the functional groups of a weak acid cation exchange resin.

[0028] In one or more embodiments, the functional group of the weakly acidic cation exchange resin is a carboxyl group.

[0029] In one or more embodiments, the functional groups of the anion exchange resin are the functional groups of a strong base anion exchange resin.

[0030] In one or more embodiments, the functional group of the strong base anion exchange resin is -N(CH3)3. + .

[0031] In one or more embodiments, the chelating resin is a macroporous styrene resin.

[0032] In one or more embodiments, the chelating resin is one or more selected from Lanxess MDS TP 220 resin, Amberlite IRC-748 and Dow M4195 chelating resin.

[0033] In one or more embodiments, the macroporous adsorption resin is a network cross-linked aromatic polymer.

[0034] In one or more embodiments, the macroporous adsorption resin is one or more selected from Amberlite XAD4, Amberlite XAD7HP, Amberlite XAD16N and Amberlite XAD1600N.

[0035] In one or more embodiments, the mixed resin is modified and washed.

[0036] In one or more embodiments, the modification process includes: ammoniation modification of the mixed resin using an ammonia solution to obtain a modified mixed resin.

[0037] In one or more embodiments, the ammonia solution is an aqueous solution of ammonium hydroxide.

[0038] In one or more embodiments, the mixed resin is contacted sequentially with water, an aqueous solution of an inorganic acid, water, an aqueous solution of ammonium hydroxide, and water.

[0039] In one or more embodiments, the washing process includes rinsing the modified mixed resin with an organic solvent until the moisture content of the filtrate is ≤0.012%.

[0040] In one or more embodiments, the process involves first circulating the solution with an organic solvent, followed by rinsing ≥12 times with fresh organic solvent.

[0041] In one or more embodiments, the purity of the organic solvent is ≥99.9%.

[0042] In one or more embodiments, the water content of the organic solvent is less than 50 ppm.

[0043] In one or more embodiments, the content of a single metal impurity in the organic solvent is less than 1 ppb.

[0044] In one or more embodiments, the organic solvent is selected from one or more of methanol, ethanol, acetone, and propylene glycol methyl ether acetate.

[0045] In one or more embodiments, the organic solvent is ethanol.

[0046] Another aspect of the present invention provides a method for preparing a mixed resin according to any embodiment herein, the method comprising: feeding a monomer phase containing monomers into an aqueous phase containing water and a dispersant and stirring, then adding an initiator to induce a polymerization reaction, drying to obtain a modified resin, and then mixing the prepared modified resin with a chelating resin and a macroporous adsorption resin, and sieving to obtain the mixed resin.

[0047] In one or more embodiments, the temperature of the aqueous phase during feeding is 40–80°C.

[0048] In one or more embodiments, the temperature of the aqueous phase during feeding is 40–60°C.

[0049] In one or more embodiments, the stirring speed is 100–800 r / min.

[0050] In one or more embodiments, the stirring speed is 150–250 r / min.

[0051] In one or more embodiments, the polymerization reaction is carried out at a temperature of 75–105°C.

[0052] In one or more embodiments, the polymerization reaction is carried out at a temperature of 75–90°C.

[0053] In one or more embodiments, the polymerization reaction takes 2 to 8 hours.

[0054] In one or more embodiments, the polymerization reaction takes 2 to 4 hours.

[0055] In one or more embodiments, the monomer phase comprises styrene, divinylbenzene, disodium maleate, and aminosulfonate, and trimethylamine is added to the reaction system after the monomer phase is added and before the initiator is added; the aminosulfonate is preferably sodium aminosulfonate and / or potassium aminosulfonate.

[0056] In one or more embodiments, the amount of disodium maleate is 0.01 to 0.05 g, the amount of aminosulfonate is 0.005 to 0.02 g, and the amount of trimethylamine is 0.02 to 0.1 mL relative to 1 g of styrene.

[0057] Another aspect of the present invention provides a method for purifying a photoresist solution, the method comprising: passing the photoresist solution to be purified through a perfluoroalkoxy resin column containing the mixed resin described in any embodiment of the present invention to obtain a purified photoresist solution.

[0058] In one or more embodiments, the purification method involves using a pneumatic diaphragm pump to drive the photoresist solution to be purified through a perfluoroalkoxy resin column packed with mixed resins.

[0059] In one or more embodiments, the photoresist is a KrF photoresist, an ArF photoresist, or an EUV photoresist.

[0060] In one or more embodiments, the photoresist solution to be purified contains metal impurities, including one or more of Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Pd, Ag, Cd, Sn, Au, and Pb.

[0061] In one or more embodiments, the photoresist solution to be purified contains an organic solvent, wherein the mass fraction of the organic solvent in the photoresist solution is ≥60%, and the organic solvent is selected from one or more of alcohol organic solvents, ester organic solvents, and ether organic solvents.

[0062] In one or more embodiments, the solid content of the photoresist solution to be purified is ≤40wt%.

[0063] In one or more embodiments, the solid content of the photoresist solution to be purified is ≤30wt%.

[0064] In one or more embodiments, the solid content of the photoresist solution to be purified is ≤20wt%.

[0065] In one or more embodiments, the total content of metal impurities in the photoresist solution to be purified is ≥10ppm.

[0066] In one or more embodiments, the total content of metal impurities in the photoresist solution to be purified is 10 to 20 ppm.

[0067] In one or more embodiments, the number of particles with a diameter greater than 0.1 micrometers per milliliter of the photoresist solution to be purified is ≥10,000.

[0068] In one or more embodiments, the number of particles with a diameter greater than 0.1 micrometers per milliliter of the photoresist solution to be purified is 10,000 to 20,000.

[0069] In one or more embodiments, the photoresist solution to be purified flows through a perfluoroalkoxy resin column packed with mixed resin at a flow rate ≤100 mL / min.

[0070] In one or more embodiments, the photoresist solution to be purified flows through a perfluoroalkoxy resin column packed with mixed resin at a flow rate of 40–60 mL / min.

[0071] In one or more embodiments, the contact time between the photoresist solution to be purified and the mixed resin is ≥1 hour.

[0072] In one or more embodiments, the contact time between the photoresist solution to be purified and the mixed resin is 1 to 10 hours.

[0073] Another aspect of the present invention provides a photoresist solution purified by the purification method described in any embodiment of the present invention, wherein the total content of metal impurities in the photoresist solution is ≤15ppb.

[0074] In one or more embodiments, the total metal impurity content of the photoresist solution is ≤10 ppb.

[0075] In one or more embodiments, the total metal impurity content of the photoresist solution is ≤5 ppb.

[0076] Another aspect of the present invention provides a photoresist solution according to any embodiment of the present invention, wherein the photoresist solution is neutral in acidity or alkalinity.

[0077] The present invention has the following beneficial effects:

[0078] The uniform particle size mixing resin and method of the present invention can not only efficiently reduce the content of metal impurities in photoresist, but also effectively reduce the residual acid in photoresist solution, while obtaining a clear and transparent photoresist solution.

[0079] In the process of treating photoresist with the mixed resin of the present invention, by optimizing parameters such as resin particle uniformity coefficient, resin type, ratio of functional groups of cation exchange resin to functional groups of anion exchange resin in modified resin, and cycle time, it is possible to reduce the total gold impurities in a 20wt% photoresist solution to ≤15ppb, or even ≤10ppb, more preferably ≤5ppb, and reduce the content of single metal impurities to ≤2ppb.

[0080] The mixed resin of this invention has a strong ability to treat metal impurities and an extremely low residual acid content, which has great social and economic benefits.

[0081] The mixed resin of the present invention is particularly suitable for treating photoresist solutions with acid-instable components, and has broad application prospects and good economic benefits in the field of integrated circuit materials. Attached Figure Description

[0082] Figure 1 This is a schematic diagram of the deacidification experiment for the mixed resin in Example 1.

[0083] Figure 2 The graph shows a comparison of the purification effects of the mixed resins in Examples 1-4 on the photoresist solution.

[0084] Figure 3 A comparison of the purification effects of the mixed resin used in Example 1 on KrF photoresist solutions with 20 wt% solid content and 30 wt% solid content. Detailed Implementation Plan

[0085] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0086] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0087] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0088] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0089] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0090] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope defined by the claims.

[0091] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0092] In this invention, uniform particle size mixed resin refers to a mixed resin with relatively uniform particle size. The uniformity coefficient can be used to characterize the uniformity of particle size. The uniformity coefficient is the ratio of the sieve aperture through which 60% of the particles pass to the sieve aperture through which 10% of the particles pass. The closer the uniformity coefficient is to 1, the more uniform the particle size. In this invention, uniform particle size mixed resin refers to a mixed resin with a uniformity coefficient of 1 to 1.5, preferably 1 to 1.3.

[0093] In this invention, the mixed resin is composed of chelating resin, modified resin, and macroporous adsorption resin; the modified resin is an ion exchange resin containing functional groups of both cation exchange resin and anion exchange resin; the functional groups of the gel-type cation exchange resin can be functional groups of strong acid cation exchange resin, and the functional group is a sulfonic acid group; the functional groups of the macroporous cation exchange resin can be functional groups of weak acid cation exchange resin, and the functional group is a carboxyl group; the functional groups of the anion exchange resin can be functional groups of strong base anion exchange resin, and the functional group is -N(CH3)3. + The chelating resin can be a macroporous styrene resin with a functional group of bispyridine methylamine; the macroporous adsorption resin is a large network cross-linked aromatic polymer.

[0094] The modified resin of this invention is an ion exchange resin. In some embodiments, the ion exchange resin is one that simultaneously contains sulfonic acid groups, carboxyl groups, and -N(CH3)3. + A novel ion exchange resin with three functional groups.

[0095] In this invention, the functional groups of the cation exchange resin treat metal ions to generate H+. + The functional groups of anion exchange resin treat the OH- generated by anions. - By optimizing the type and molar ratio of resin, metal ions can be removed more efficiently and deeply, while minimizing the generation of acid during the purification process to avoid damage to the structure of the photolithography material.

[0096] In some embodiments, the mixed resin is a resin material made by mixing raw materials for preparing cation exchange resin and raw materials for preparing anion exchange resin, and then highly transforming and refining the modified resin, chelating resin, and macroporous adsorption resin. The resin purity is nuclear energy level and the transformation rate is greater than 99.9%.

[0097] In some embodiments, the backbone of the modified resin, which is the main component of the mixed resin, is a styrene-divinylbenzene copolymer.

[0098] In this invention, PFA refers to perfluoroalkoxy resin, that is, a copolymer of a small amount of perfluoropropyl perfluorovinyl ether and polytetrafluoroethylene.

[0099] The mixed resin of the present invention includes a chelating resin, a modified resin, and a macroporous adsorption resin; in the modified resin, the molar ratio of the functional groups of the cation exchange resin to the functional groups of the anion exchange resin is 1:1 to 1:5, for example 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, 1:3.2, 1:3.4, 1:3.6, 1:3.8, 1:4, 1:4.2, 1:4.4, 1:4.6, 1:4.8, preferably 1:1.7 to 1:2.3, more preferably 1:1.7 to 1:1.9; the mixed resin... The resin is in the form of spherical particles with an average particle size of 0.4–1.2 mm, such as 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, or 1.1 mm, preferably 0.5–0.6 mm; the uniformity coefficient of the mixed resin is 1.05–1.95, such as 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, or 1.9, preferably 1.05–1.3, more preferably 1.05–1.25, and even more preferably 1.05–1.15.

[0100] The modified resin has a molar fraction of 50% to 90% in the mixed resin, for example 55%, 60%, 65%, 70%, 75%, 80%, 85%, preferably 70% to 90%, and more preferably 75% to 85%.

[0101] The molar fraction of the macroporous adsorption resin in the mixed resin is 1% to 30%, for example 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, preferably 5% to 20%.

[0102] The chelating resin has a molar fraction of 1% to 40% in the mixed resin, for example, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, preferably 5% to 20%;

[0103] In the functional groups of the cation exchange resin, the molar ratio of the functional groups of the gel-type cation exchange resin to the functional groups of the macroporous cation exchange resin is 4:1 to 1:4, for example, 3:1, 2:1, 1:1, 1:2, 1:3, preferably 4:1 to 1:1, and more preferably 4:1 to 3:1.

[0104] In some implementations, the mixed resin undergoes modification and washing treatment.

[0105] The modification treatment includes: ammonifying the mixed resin with an ammonia solution to obtain the modified mixed resin, wherein the ammonia solution is preferably an aqueous solution of ammonium hydroxide; preferably, the modification treatment is to contact the mixed resin sequentially with water, an aqueous solution of inorganic acid, water, an aqueous solution of ammonium hydroxide, and water.

[0106] The washing process includes rinsing the modified mixed resin with an organic solvent until the moisture content of the filtrate is ≤0.012%, for example, 0.011%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, or 0.005%; preferably, the mixture is first circulated with an organic solvent, and then rinsed ≥12 times with fresh organic solvent, for example, 14, 16, 18, or 20 times; preferably, the purity of the organic solvent is ≥99.9%, for example, 99.92%, 99.94%, 99.96%, or 99.99%. 98%; moisture content less than 50 ppm, for example 48 ppm, 46 ppm, 44 ppm, 42 ppm, 40 ppm, 38 ppm, 36 ppm, 34 ppm, 32 ppm, 30 ppm, 28 ppm, 26 ppm, 24 ppm, 22 ppm, 20 ppm; single gold impurities less than 1 ppb, for example 0.8 ppb, 0.6 ppb, 0.4 ppb, 0.2 ppb; preferably, the organic solvent is selected from one or more of methanol, ethanol, acetone and propylene glycol methyl ether acetate, preferably ethanol.

[0107] The modified resin in this invention can be prepared using a suspension polymerization process. This involves uniformly mixing the initiator and monomers, adding the mixture to an aqueous phase composed of ultrapure water, a dispersant, and additives to initiate a polymerization reaction, and then modifying, washing, drying, and sieving to obtain the modified resin. During the preparation process, the temperature of the aqueous phase during feeding is 40–80°C, for example, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, or 75°C, preferably 40–60°C; the stirring speed is 100–800 r / min, for example, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, 550 r / min, 600 r / min, or 600 r / min. 50 r / min, 700 r / min, 750 r / min, preferably 150–250 r / min; monomer phase feed rate is 20–100 mL / min, for example 22 mL / min, 24 mL / min, 26 mL / min, 28 mL / min, 30 mL / min, 32 mL / min, 34 mL / min, 36 mL / min, 38 mL / min, 40 mL / min, 42 mL / min, 44 mL / min, 46 mL / min, 48 mL / min, 50 mL / min, 52 mL / min, 54 mL / min, 56 mL / min, 58 mL / min, 60 mL / min, 62 mL / min, 64 mL / min, 66 mL / min, 68 mL / min, 70 mL / min, 72 mL / min, 74 mL / min, 76 mL / min, 78 mL / min, 80 mL / min, 82 mL / min The flow rates are 84 mL / min, 86 mL / min, 88 mL / min, 90 mL / min, 92 mL / min, 94 mL / min, 96 mL / min, and 98 mL / min, preferably 30–40 mL / min; the polymerization reaction temperature is 75–105℃, for example 80℃, 85℃, 90℃, 95℃, and 100℃, preferably 75–90℃; the polymerization reaction time is 2–8 h, for example 3 h, 4 h, 5 h, 6 h, and 7 h, preferably 2–4 h.

[0108] In this invention, the monomer phase includes styrene, divinylbenzene, disodium maleate, and aminosulfonate. Trimethylamine is added to the reaction system after the monomer phase and before the initiator. The aminosulfonate is preferably sodium aminosulfonate and / or potassium aminosulfonate. Preferably, the amount of disodium maleate relative to 1g of styrene is 0.01–0.05g, for example, 0.015g, 0.02g, 0.025g, 0.03g, 0.035g, 0.04g, or 0.045g, and the amount of aminosulfonate is 0.005–… 0.02g, for example 0.006g, 0.007g, 0.008g, 0.009g, 0.001g, 0.0011g, 0.0012g, 0.0013g, 0.0014g, 0.0015g, 0.0016g, 0.0017g, 0.0018g, 0.0019g, and the amount of trimethylamine used is 0.02-0.1mL, for example 0.03mL, 0.04mL, 0.05mL, 0.06mL, 0.07mL, 0.08mL, 0.09mL.

[0109] In some implementations, the mixed resin of the present invention can be prepared by controlling the monomer phase feed rate, aqueous phase temperature during feeding, stirring speed, polymerization temperature, polymerization time and / or the aperture size of the feed plate, followed by modification, washing, drying, mixing with chelating resin and macroporous adsorption resin, and sieving.

[0110] In some implementations, the mixed resin is modified by deep sulfonation and amination, and then the modified mixed resin is contacted with a photoresist solution containing metal ion contaminants.

[0111] The mixed resin of the present invention can be used to purify photoresists, including but not limited to KrF photoresist, ArF photoresist, EUV photoresist, etc.

[0112] In this invention, the photoresist to be purified contains metallic impurities, including but not limited to at least two of the following: Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Pd, Ag, Cd, Sn, Au, and Pb. The advantage of the purification system and method of this invention is that it can purify photoresist with a total metallic impurity content of not less than 10 ppm (e.g., not less than 20 ppm).

[0113] In this invention, the photoresist to be purified may contain particles of different sizes. The advantage of the mixed resin and purification method of this invention is that it can process photoresist solutions with a particle size greater than 0.1 μm of at least 10,000 particles per milliliter.

[0114] In this invention, the photoresist to be purified contains an organic solvent, and the mass fraction of the organic solvent can be no less than 60%, for example, no less than 80%. The organic solvent can be one or more of alcohol organic solvents, ester organic solvents and ether organic solvents.

[0115] In this invention, the solid content of the photoresist solution to be purified is ≤40wt%, for example 35wt%, 30wt%, 25wt%, 20wt%, 15wt%, 10wt%, 5wt%, preferably ≤30wt%, more preferably ≤20wt%.

[0116] In some implementations, the mixed resin is pretreated with electronic-grade organic solvents (such as methanol, ethanol, acetone, propylene glycol methyl ether acetate, etc.) before use. The purpose is to further remove impurities and moisture from the mixed resin, improve the purification effect on the photoresist, and avoid introducing water impurities into the photoresist system. The modified resin in the mixed resin is ammonified with ammonium hydroxide solution, and the mixed resin is treated with ultrapure water to improve its gold impurity removal activity.

[0117] In this invention, treating the mixed resin sequentially with ultrapure water and inorganic acid solution in a PFA column helps to reduce the metal ion content in the mixed resin.

[0118] In this invention, the mixed resin can efficiently remove metal impurities from photoresist. At the same time, by adjusting the ratio of chelating resin, modified resin and macroporous adsorption resin in the mixed resin, the optimal effect of acid removal can be obtained. Specifically, the optimal effect of acid removal is obtained by configuring modified resins with different molar proportions of functional groups of anion exchange resin and functional groups of cation exchange resin, as well as modified resins with different molar proportions in the mixed resin.

[0119] The content of a single metal impurity in the photoresist purified by the mixed resin of the present invention is no higher than 2 ppb, and the content of total metal impurities is no higher than 10 ppb.

[0120] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. The methods, reagents, and materials used in the embodiments are conventional methods, reagents, and materials in the art, unless otherwise stated. The raw material compounds in the embodiments are all commercially available.

[0121] The photoresist solutions used in the following examples and comparative examples contain metal impurities including, but not limited to, Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Pd, Ag, Cd, Sn, Au, and Pb, with a total content of not less than 10 ppm.

[0122] In this invention, the total metal impurity content in the photoresist solution before and after purification was measured using inductively coupled plasma mass spectrometry (ICP-MS).

[0123] In this invention, the method for testing the particle size and number of particles in the photoresist solution is: laser particle size analysis.

[0124] In this invention, the formula for calculating the film retention rate is: film retention rate = (photoresist thickness after development / photoresist thickness before exposure) × 100%.

[0125] In this invention, the method for testing the average particle size of the resin is as follows: First, the resin sample is dispersed evenly and then added to a laser particle size analyzer. The instrument irradiates the sample with a laser to produce light scattering. The particle size and distribution of the sample particles are calculated based on the intensity and angle of the light scattering. The obtained data is exported to obtain the average particle size value of the resin sample.

[0126] Preparation Example 1

[0127] A suspension polymerization process was employed. 4L of ultrapure water and 10g of polyvinyl alcohol (polyvinyl alcohol) dispersant were added to a 10L reactor. The stirrer was turned on at 200rpm, and the mixture was heated to 60℃ to obtain the aqueous phase. An aqueous solution of 1800g styrene, 200g divinylbenzene, 32g disodium maleate, and 120g of 10% sodium aminosulfonate was mixed thoroughly to obtain the monomer phase. This monomer phase was added to the reactor at a feed rate of 20mL / min, and stirring continued. When the temperature reached 70℃, heating was stopped, and 80mL of pure trimethylamine was added. Nitrogen gas was purged for 10min, and 30g of benzoyl peroxide initiator was added to the reactor. The mixture was then heated to 90℃ for polymerization, and maintained for 2 hours. After polymerization, drying yields modified resins containing functional groups from cation exchange resins and anion exchange resins. The functional groups of the cation exchange resins include sulfonic acid groups (from gel-type cation exchange resins) and carboxyl groups (from macroporous cation exchange resins). The functional groups of the anion exchange resins are the strong-base anion exchange resin functional groups -N(CH3)3. + The modified resin was mixed with chelating resin Amberlite IRC-748 and macroporous adsorption resin Amberlite XAD4. After sieving, a mixed resin with an average particle size of 0.5 mm and a uniformity coefficient of 1.1 was obtained. The mixed resin was then modified and washed.

[0128] The mixed resin consists of modified resin, macroporous adsorption resin, and chelating resin. In the mixed resin, the molar fraction of modified resin is 80%, the molar fraction of macroporous adsorption resin is 10%, and the molar fraction of chelating resin is 10%. In the modified resin, the molar ratio of functional groups of the cation exchange resin to the functional groups of the anion exchange resin is 1:1.8, and the molar ratio of functional groups of the gel-type cation exchange resin to the functional groups of the macroporous cation exchange resin is 4:1.

[0129] The modification and washing process of the mixed resin is as follows: Modification: 1.6L of mixed resin to be washed is packed into a PFA column. The mixed resin packed into the PFA column is treated sequentially with 2L of ultrapure water, 2L of 0.1mol / L hydrochloric acid, and 2L of ultrapure water. Then, the mixed resin packed into the PFA column is ammonified with 2L of 0.1mol / L ammonium hydroxide solution. Finally, the mixed resin packed into the PFA column is treated with 2L of ultrapure water.

[0130] Washing: The modified mixed resin was dynamically circulated and rinsed with 2L of electronic-grade ethanol (purity ≥99.9%, water content <50ppm, single metal impurity content <1ppb) to remove water from the resin for 2 hours. Then, it was rinsed 12 times with fresh electronic-grade ethanol (purity ≥99.9%, water content <50ppm, single metal impurity content <1ppb). After each rinse, the water content of the mixed resin filtrate was measured using a Karl Fischer analyzer. Two samples were measured each time, and the average value was taken. During the rinsing process with fresh anhydrous ethanol, the more times anhydrous ethanol was used for rinsing, the more thoroughly the anhydrous ethanol replaced the water in the resin, and the water content of the filtrate gradually decreased. The relationship between the number of anhydrous ethanol rinsing cycles and the water content of the mixed resin filtrate after rinsing is shown in Table 1. After 12 rinses with fresh anhydrous ethanol, the water content of the filtrate decreased to 0.12%.

[0131] Table 1: Moisture content in filtrate after washing mixed resin with fresh anhydrous ethanol for different numbers of times

[0132]

[0133] Acid removal experiments were conducted on the mixed resin obtained in Preparation Example 1. The specific experimental steps are as follows: Figure 1 As shown, it includes the following steps:

[0134] (1) Cation exchange resin treatment: The unpurified photoresist solution is composed of KrF photoresist resin, solvent and nonionic photoacid. KrF photoresist resin is a poly(p-hydroxystyrene) polymer with a solid content of 20%. The solvent is PGMEA and the pH of the photoresist solution is 7. After treatment with Amberlite 15WET cation exchange resin, the photoresist solution becomes acidic with a pH of 5, which will cause the photoresist to undergo a deprotection reaction.

[0135] (2) Mixed resin treatment: Using the modified and washed mixed resin from Preparation Example 1, 20 L of acidic photoresist solution with a solid content of 20% was treated in step (1). The photoresist solution was completely introduced into the PFA column using a pneumatic diaphragm pump at a flow rate of 50 mL / min, and dynamically circulated for 4 h. A photoresist solution with a pH of 7 was obtained, indicating that the mixed resin can effectively remove acid.

[0136] (3) NaCl treatment: A small amount of NaCl was added to the 20 L acidic photoresist solution with a solid content of 20% obtained in step (1) to adjust the pH of the photoresist solution to 2. Then, the photoresist solution was treated with the modified and washed mixed resin of Preparation Example 1. The photoresist solution was completely introduced into the PFA column by a pneumatic diaphragm pump at a flow rate of 50 mL / min and dynamically circulated for 4 h. After treatment, a photoresist solution with a pH of 7 was obtained, indicating that the mixed resin can still effectively remove acid. This shows that the mixed resin of Preparation Example 1 can effectively protect the photoresist from deprotection reaction.

[0137] Preparation Example 2 (corresponding to Example 2)

[0138] Preparation Example 2: The process of preparing the mixed resin is basically the same as that of Preparation Example 1, except that the mixed resin with an average particle size of 0.5 mm and a uniformity coefficient of 1.3 is obtained by sieving.

[0139] Preparation Example 3 (corresponding to Example 3)

[0140] The process of preparing the mixed resin in Preparation Example 3 is basically the same as that in Preparation Example 1, except that the mixed resin with an average particle size of 0.5 mm and a uniformity coefficient of 1.6 is obtained by sieving.

[0141] Preparation Example 4 (corresponding to Example 4)

[0142] The process of preparing the mixed resin in Preparation Example 4 is basically the same as that in Preparation Example 1, except that the mixed resin with an average particle size of 0.5 mm and a uniformity coefficient of 1.8 is obtained by sieving.

[0143] Preparation Example 5 (corresponding to Example 6)

[0144] Preparation Example 5: The process for preparing the mixed resin was basically the same as in Preparation Example 1, except that the aqueous solutions of disodium maleate and sodium aminosulfonate were added in amounts of 37.5 g and 112.5 g, respectively. A mixed resin was prepared with a molar ratio of cation exchange resin functional groups to anion exchange resin functional groups of 1:1.8 and a molar ratio of gel-type cation exchange resin functional groups to macroporous cation exchange resin functional groups of 3:1. The mixed resin was obtained by sieving, resulting in an average particle size of 0.5 mm and a uniformity coefficient of 1.1.

[0145] Preparation Example 6 (corresponding to Example 7)

[0146] Preparation Example 5: The process for preparing the mixed resin was basically the same as in Preparation Example 1, except that the amount of trimethylamine added was 375 mL. A mixed resin was prepared with a molar ratio of functional groups of cation exchange resin to functional groups of anion exchange resin of 1:2.5. The mixed resin was obtained by sieving with an average particle size of 0.5 mm and a uniformity coefficient of 1.1.

[0147] Preparation Example 7 (corresponding to Example 8)

[0148] Preparation Example 5: The process for preparing the mixed resin was basically the same as in Preparation Example 1, except that the amount of trimethylamine added was 225 mL. A mixed resin was prepared with a molar ratio of functional groups of cation exchange resin to functional groups of anion exchange resin of 1:1.5. The mixed resin was obtained by sieving with an average particle size of 0.5 mm and a uniformity coefficient of 1.1.

[0149] Example 1

[0150] The mixed resin with a uniformity coefficient of 1.1 obtained in Preparation Example 1 was packed into a 2L PFA column. In this example, the photoresist solution was a KrF photoresist solution, in which the photoresist resin was a poly(p-hydroxystyrene) polymer with a solid content of 20%, and the solvent was PGMEA. Before purification, the initial total gold impurities in the photoresist solution were 15.2 ppm, and there were 11,253 particles larger than 0.1 micrometers per milliliter of photoresist solution. 20L of the 20wt% KrF photoresist solution was introduced into the PFA column using a pneumatic diaphragm pump at a flow rate of 50 mL / min, with a dynamic self-circulation time of 4 hours.

[0151] The metal impurities in the purified photoresist solution were characterized by ICP-MS. The removal rate of gold impurities in the photoresist solution exceeded 99.9%. The content of each of the metal impurities Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Pd, Ag, Cd, Sn, Au, and Pb in the obtained photoresist solution was less than 2 ppb (e.g., ...). Figure 3As shown in the figure, the total metal impurity content was 3.92 ppb, and the film retention rate was 96.3%.

[0152] The purified photoresist solution is neutral. The hydrogen ions exchanged by the functional groups of the cation exchange resin and the hydroxide ions exchanged by the functional groups of the anion exchange resin undergo a neutralization reaction. The molar ratio of the functional groups of the anion exchange resin and the functional groups of the cation exchange resin is appropriate. The photoresist solution system will not accumulate hydrogen ions or hydroxide ions, or only accumulates a very small amount of hydrogen ions or hydroxide ions, thus avoiding the deprotection reaction caused by residual acid.

[0153] Example 2

[0154] The 20L of 20wt% KrF photoresist solution (the photoresist solution was the same as in Example 1) was purified using the same method as in Example 1, except that a mixed resin with a uniformity coefficient of 1.3 obtained in Preparation Example 2 was added to the PFA column.

[0155] The metal impurities in the purified photoresist solution were characterized by ICP-MS, and the total metal impurity content in the photoresist solution was found to be 11.85 ppb. The contents of each metal impurity are shown below. Figure 2 As shown. The purified photoresist solution is neutral.

[0156] Example 3

[0157] The 20L of 20wt% KrF photoresist solution (the photoresist solution was the same as in Example 1) was purified using the same method as in Example 1, except that a mixed resin with a uniformity coefficient of 1.6 obtained in Preparation Example 3 was added to the PFA column.

[0158] The metal impurities in the purified photoresist solution were characterized by ICP-MS, and the total metal impurity content in the photoresist solution was found to be 32.40 ppb. The contents of each metal impurity are as follows: Figure 2 As shown. The purified photoresist solution is neutral.

[0159] Example 4

[0160] The 20L of 20wt% KrF photoresist solution (the photoresist solution was the same as in Example 1) was purified using the same method as in Example 1, except that a mixed resin with a uniformity coefficient of 1.8 obtained in Preparation Example 4 was added to the PFA column.

[0161] The metal impurities in the purified photoresist solution were characterized by ICP-MS, and the total metal impurity content in the photoresist solution was found to be 60.98 ppb. The contents of each metal impurity are as follows: Figure 2 As shown. The purified photoresist solution is neutral.

[0162] Examples 1-4 used mixed resins with different homogeneity coefficients to purify the photoresist solution, and the purification effect was as follows: Figure 2 As shown. From Figure 2 As can be seen, the smaller the uniformity coefficient of the mixed resin, the better the purification effect of the photoresist solution. This indicates that the mixed resin with a small uniformity coefficient can fill more densely, reduce bypasses, and increase the contact time between the photoresist solution and the mixed resin, giving it a significant advantage in removing gold impurities from photoresist.

[0163] Example 5

[0164] 20 L of a 30 wt% KrF photoresist solution was purified using essentially the same method as in Example 1. The KrF photoresist solution contained a poly(p-hydroxystyrene) polymer with a solid content of 30% and PGMEA as the solvent. Before purification, the initial total gold impurities in the photoresist solution were 15.8 ppm, and there were 12,431 particles larger than 0.1 μm per milliliter of photoresist solution. After resin purification, the photoresist solution was neutral, and no deprotection was observed, resulting in a film retention rate of 97.2%.

[0165] The metal impurity content in the purified photoresist solution was characterized by ICP-MS. The removal rate of gold impurities exceeded 99.9%. The individual contents of the metal impurities Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Pd, Ag, Cd, Sn, Au, and Pb in the resulting photoresist solution were all less than 1 ppb, with a total metal impurity content of 12.36 ppb. This indicates that the photoresist purification system can handle high-viscosity photoresist solutions. The purified photoresist solution was neutral.

[0166] Example 6

[0167] The 20L 20wt% KrF photoresist solution was purified using a method essentially the same as in Example 1, except that the mixed resin obtained in Preparation Example 5 was added to the PFA column (the molar ratio of the functional groups of the cation exchange resin to the functional groups of the anion exchange resin was 1:1.8, and the molar ratio of the functional groups of the gel-type cation exchange resin to the functional groups of the macroporous cation exchange resin was 3:1).

[0168] The metal impurities in the purified photoresist solution were characterized by ICP-MS, and the total metal impurity content of the photoresist solution was found to be 11.2 ppb, with a film retention rate of 85.3%. The purified photoresist solution was neutral.

[0169] Example 7

[0170] The 20L 20wt% KrF photoresist solution was purified using essentially the same method as in Example 1, except that the mixed resin obtained in Preparation Example 6 was added to the PFA column (the molar ratio of the functional groups of the cation exchange resin to the functional groups of the anion exchange resin was 1:1.5).

[0171] The metal impurities in the purified photoresist solution were characterized by ICP-MS, and the total metal impurity content of the photoresist solution was found to be 81.2 ppb, with a film retention rate of 35.2%. The pH of the purified photoresist solution was 5.5.

[0172] Example 8

[0173] The 20L 20wt% KrF photoresist solution was purified using essentially the same method as in Example 1, except that the mixed resin obtained in Preparation Example 7 was added to the PFA column (the molar ratio of the functional groups of the cation exchange resin to the functional groups of the anion exchange resin was 1:2.5).

[0174] The metal impurities in the purified photoresist solution were characterized by ICP-MS, and the total metal impurity content of the photoresist solution was found to be 19.3 ppb, with a film retention rate of 88.2%. The pH of the purified photoresist solution was 6.5.

[0175] Examples 9-15

[0176] The 20L of 20wt% KrF photoresist solution from Example 1 or the 30wt% KrF photoresist solution from Example 5 were purified using essentially the same method as in Example 1, with the only difference being the dynamic self-circulation time.

[0177] The metal impurity content in the purified photoresist solution was characterized by ICP-MS, and the total metal impurity content of the photoresist solution was measured as follows: Figure 3 As shown in Table 2, the photoresist retention rates of each embodiment are shown in Table 2. The purified photoresist solutions of each embodiment are neutral.

[0178] Table 2: Total gold impurity content and photoresist retention rate of photoresist solutions in Examples 1 and 9-15

[0179] Example 9 20% KrF photoresist solution 1h 6.74ppb 97.1％ Example 10 20% KrF photoresist solution 2h 5.56ppb 96.4％ Example 11 20% KrF photoresist solution 3h 3.56ppb 96.8％ Example 1 20% KrF photoresist solution 4h 3.92ppb 96.3％ Example 12 30% KrF photoresist solution 1h 12.36ppb 97.2％ Example 13 30% KrF photoresist solution 2h 7.88ppb 98.1％ Example 14 30% KrF photoresist solution 3h 5.66ppb 99.1％ Example 15 30% KrF photoresist solution 4h 6.72ppb 98.9％

[0180] The specific embodiments of the present invention have been described above by way of example. However, the scope of protection of the present invention is not limited to the above exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A mixed resin, characterized in that, The mixed resin includes chelating resin, modified resin, and macroporous adsorption resin. The modified resin is an ion exchange resin containing functional groups of both cation exchange resin and anion exchange resin; the functional groups of the cation exchange resin include functional groups of gel-type cation exchange resin and functional groups of macroporous cation exchange resin; the functional groups of the gel-type cation exchange resin are functional groups of strong acid cation exchange resin, the functional groups of the macroporous cation exchange resin are functional groups of weak acid cation exchange resin, and the functional groups of the anion exchange resin are functional groups of strong base anion exchange resin. In the modified resin, the molar ratio of the functional groups of the cation exchange resin to the functional groups of the anion exchange resin is 1:1.5 to 1:2.5; The mixed resin consists of spherical particles with an average particle size of 0.4~1.2mm and a uniformity coefficient of 1.05~1.

95.

2. The mixed resin as described in claim 1, characterized in that, The mixed resin has one or more of the following characteristics: The monomers of the modified resin include styrene and divinylbenzene; The modified resin has a molar fraction of 50% to 90% in the mixed resin; The macroporous adsorption resin has a molar fraction of 1% to 30% in the mixed resin; The chelating resin has a molar fraction of 1% to 40% in the mixed resin; In the modified resin, the molar ratio of the functional groups of the cation exchange resin to the functional groups of the anion exchange resin is 1:1.7 to 1:2.

3. The average particle size of the mixed resin is 0.5~0.6 mm; The uniformity coefficient of the mixed resin is 1.05~1.

3.

3. The mixed resin as described in claim 2, characterized in that, The modified resin contains styrene and divinylbenzene as monomers, with a mass ratio of styrene to divinylbenzene of 1:0.10 to 1:0.

12.

4. The mixed resin as described in claim 2, characterized in that, The modified resin has a molar fraction of 70% to 90% in the mixed resin.

5. The mixed resin as described in claim 2, characterized in that, The modified resin has a molar fraction of 75% to 85% in the mixed resin.

6. The mixed resin as described in claim 2, characterized in that, The macroporous adsorption resin has a molar fraction of 5% to 20% in the mixed resin.

7. The mixed resin as described in claim 2, characterized in that, The chelating resin has a molar fraction of 5% to 20% in the mixed resin.

8. The mixed resin as described in claim 2, characterized in that, In the modified resin, the molar ratio of the functional groups of the cation exchange resin to the functional groups of the anion exchange resin is 1:1.7 to 1:1.

9.

9. The mixed resin as described in claim 2, characterized in that, The uniformity coefficient of the mixed resin is 1.05~1.

25.

10. The mixed resin as described in claim 2, characterized in that, The uniformity coefficient of the mixed resin is 1.05~1.

15.

11. The mixed resin as claimed in claim 1, characterized in that, The mixed resin has one or more of the following characteristics: In the functional groups of the cation exchange resin, the molar ratio of the functional groups of the gel-type cation exchange resin to the functional groups of the macroporous cation exchange resin is 4:1 to 1:

4. The functional group of the strong acid cation exchange resin is a sulfonic acid group, the functional group of the weak acid cation exchange resin is a carboxyl group, and the functional group of the strong base anion exchange resin is preferably -N(CH3)3. + ; The chelating resin is a macroporous styrene resin; The macroporous adsorption resin is a network cross-linked aromatic polymer.

12. The mixed resin as described in claim 11, characterized in that, The molar ratio of the functional groups of the gel-type cation exchange resin to the functional groups of the macroporous cation exchange resin is 4:1 to 1:

1.

13. The mixed resin as described in claim 11, characterized in that, The molar ratio of the functional groups of the gel-type cation exchange resin to the functional groups of the macroporous cation exchange resin is 4:1 to 3:

1.

14. The mixed resin as described in claim 11, characterized in that, The chelating resin is one or more selected from Lanxess MDS TP 220 resin, Amberlite IRC-748 and Dow M4195 chelating resin.

15. The mixed resin as described in claim 11, characterized in that, The macroporous adsorption resin is selected from one or more of Amberlite XAD4, Amberlite XAD7HP, Amberlite XAD16N and Amberlite XAD1600N.

16. The mixed resin as claimed in claim 1, characterized in that, The mixed resin undergoes modification and washing treatment; The modification treatment includes: ammonifying the mixed resin with an ammonia solution to obtain the modified mixed resin, wherein the ammonia solution is preferably an aqueous solution of ammonium hydroxide; The washing process includes rinsing the modified mixed resin with an organic solvent until the moisture content of the filtrate is ≤0.012%.

17. The mixed resin as described in claim 16, characterized in that, The modification treatment includes: contacting the mixed resin sequentially with water, an aqueous solution of inorganic acid, water, an aqueous solution of ammonium hydroxide, and water.

18. The mixed resin as described in claim 16, characterized in that, The washing process includes: first, rinsing with an organic solvent in a circulating manner, and then rinsing with fresh organic solvent ≥12 times.

19. The mixed resin as described in claim 18, characterized in that, The organic solvent has a purity of ≥99.9%, a moisture content of less than 50 ppm, and a single metal impurity content of less than 1 ppb.

20. The mixed resin as described in claim 18, characterized in that, The organic solvent is selected from one or more of methanol, ethanol, acetone, and propylene glycol methyl ether acetate.

21. The mixed resin as described in claim 18, characterized in that, The organic solvent is ethanol.

22. The method for preparing the mixed resin according to any one of claims 1-21, characterized in that, The preparation method includes: feeding a monomer phase containing monomers into an aqueous phase containing water and a dispersant and stirring, then adding an initiator to induce a polymerization reaction, drying to obtain a modified resin, and then mixing the prepared modified resin with a chelating resin and a macroporous adsorption resin, and sieving to obtain the mixed resin.

23. The preparation method according to claim 22, characterized in that, The preparation method has one or more of the following characteristics: During feeding, the temperature of the aqueous phase is 40~80℃; The stirring speed is 100~800 r / min; The polymerization reaction is carried out at a temperature of 75~105℃; The polymerization reaction takes 2-8 hours; The monomer phase includes styrene, divinylbenzene, disodium maleate, and aminosulfonate. Trimethylamine is added to the reaction system after the monomer phase is added and before the initiator is added.

24. The preparation method according to claim 23, characterized in that, During feeding, the temperature of the aqueous phase is 40~60℃.

25. The preparation method according to claim 23, characterized in that, The stirring speed is 150~250 r / min.

26. The preparation method according to claim 23, characterized in that, The polymerization reaction is carried out at a temperature of 75~90℃.

27. The preparation method according to claim 23, characterized in that, The polymerization reaction takes 2 to 4 hours.

28. The preparation method according to claim 23, characterized in that, The aminosulfonate is sodium aminosulfonate and / or potassium aminosulfonate.

29. The preparation method according to claim 23, characterized in that, Relative to 1g of styrene, the amount of disodium maleate is 0.01~0.05g, the amount of aminosulfonate is 0.005~0.02g, and the amount of trimethylamine is 0.02~0.1mL.

30. A method for purifying a photoresist solution, characterized in that, The purification method includes passing the photoresist solution to be purified through a perfluoroalkoxy resin column containing any one of the mixed resins of claims 1-21 to obtain a purified photoresist solution.

31. The purification method according to claim 30, characterized in that, The purification method has one or more of the following characteristics: The photoresist solution to be purified is driven through a column of perfluoroalkoxy resin packed with mixed resin using a pneumatic diaphragm pump. The photoresist is KrF photoresist, ArF photoresist, or EUV photoresist; The photoresist solution to be purified contains metallic impurities, which include one or more of the following: Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Pd, Ag, Cd, Sn, Au, and Pb. The photoresist solution to be purified contains an organic solvent, wherein the mass fraction of the organic solvent in the photoresist solution is ≥60%, and the organic solvent is selected from one or more of alcohol organic solvents, ester organic solvents, and ether organic solvents; The solid content of the photoresist solution to be purified is ≤40wt%; The total content of metal impurities in the photoresist solution to be purified is ≥10ppm; The number of particles with a diameter greater than 0.1 micrometers per milliliter of the photoresist solution to be purified is ≥10,000; The flow rate of the photoresist solution to be purified through the perfluoroalkoxy resin column packed with mixed resin is ≤100 mL / min. The contact time between the photoresist solution to be purified and the mixed resin is ≥1 hour.

32. The purification method according to claim 31, characterized in that, The solid content of the photoresist solution to be purified is ≤30wt%.

33. The purification method according to claim 31, characterized in that, The solid content of the photoresist solution to be purified is ≤20wt%.

34. The purification method according to claim 31, characterized in that, The total content of metal impurities in the photoresist solution to be purified is 10~20 ppm.

35. The purification method according to claim 31, characterized in that, The number of particles with a diameter greater than 0.1 micrometers in each milliliter of the photoresist solution to be purified is 10,000 to 20,000.

36. The purification method according to claim 31, characterized in that, The photoresist solution to be purified flows through a perfluoroalkoxy resin column packed with mixed resin at a flow rate of 40-60 mL / min.

37. The purification method according to claim 31, characterized in that, The contact time between the photoresist solution to be purified and the mixed resin is 1 to 10 hours.

38. The photoresist solution purified by the purification method according to any one of claims 30-37, characterized in that, The total content of metal impurities in the photoresist solution is ≤15ppb.

39. The photoresist solution as described in claim 38, characterized in that, The total content of metal impurities in the photoresist solution is ≤10ppb.

40. The photoresist solution as described in claim 38, characterized in that, The total content of metal impurities in the photoresist solution is ≤5ppb.

41. The photoresist solution as described in claim 38, characterized in that, The photoresist solution is neutral in pH.

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