Silica gel material modified with thiol and 4-methylaminopyridine bifunctional groups and its application in photoresist resin preparation

Abstract

The application discloses a kind of thiol and 4-methyl amino pyridine bifunctional group modified silica gel base material and its preparation and its application in catalytic synthesis, removal of acidic and alkaline residual impurities, removal of metal ion impurities for a kind of 248nm photoresist resin.The application is suitable for semiconductor photoresist resin electronic chemical synthesis and purification technical field.A new type of modified silica gel material containing bifunctional group is provided, which can be used for catalytic synthesis and purification of semiconductor, display electronic chemicals, especially suitable for catalytic synthesis and purification of metal ion impurities for a kind of semiconductor chemical amplification type photoresist resin, and has wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of polymer technology, specifically to a modified silicone-based material containing thiol and 4-methylaminopyridine bifunctional groups and its application in the preparation of photoresist resins. Background Technology

[0002] In the photolithography process of semiconductor silicon wafers, photoresist is one of the key materials. Photoresist, also known as photoresist, refers to a photoresist thin film material whose solubility changes when exposed to ultraviolet light, electron beams, ion beams, X-rays, etc. It is a key material in integrated circuit manufacturing.

[0003] Photoresists used in semiconductor ICs are categorized into g-line (wavelength 436nm), i-line (wavelength 365nm), KrF (wavelength 248nm), ArF (dry wavelength 193nm), and EUV (wavelength 13.5nm). As the ultraviolet wavelength for photolithography shortens, the resolution increases. With the development of increasingly refined semiconductor patterns, the requirements for impurities in photoresist and other materials are becoming more stringent. The difficulty in photoresist preparation, besides formulation performance, lies primarily in the quality of its components: resin, initiator, monomer, solvent, and other additives. Among these, the resin component is the most crucial, directly determining the performance and quality of the photoresist composition.

[0004] The quality requirements for resin components in semiconductor photoresists are very high. Particularly, the requirements for impurities (organic impurities, various foreign matter, metal ions, etc.) are very stringent; impurity levels must meet standards. Metal impurities have a negative impact on semiconductor manufacturing; therefore, the gold impurity content in photoresist materials that directly contact the silicon wafer must be controlled at extremely low levels. High levels of metal impurities in the photoresist greatly increase the risk of these impurities remaining on the semiconductor substrate surface, ultimately damaging the semiconductor's electrical properties, reducing chip yield, and significantly increasing costs. It is necessary to explore and experiment with different photoresist component materials with varying structures to find synthesis and purification methods to remove foreign matter, metals, and other impurities. In short, for the various photoresists and other insulating films, anti-reflective layers, and other materials used in the aforementioned fine photolithography, the content of various organic impurities and metal ion impurities must be controlled to extremely low levels. Therefore, the content of metal impurities in photoresists and their upstream resins and intermediates must be strictly controlled.

[0005] In high-resolution I-line and KrF and lower-level photolithography processes, chemical amplification photoresist is often used. This means that the photoacid generator (PAG) in the photoresist generates protons by contacting photons in the exposure area, thereby catalyzing the dissociation of acid-sensitive groups in the resin and creating patterns by differentiating the solubility of the developer.

[0006] The mechanism of photolithography in chemically amplified photoresists relies on trace amounts of photoacid-generating agents in the photoresist formulation. When irradiated with ultraviolet light of a specific wavelength, these agents cause the chemical bonds in the resin molecules of the positive photoresist to break, promoting rapid dissolution. Various organic polymers, such as o-(or m-)cresol-formaldehyde resin, polyacrylic acid and its derivatives, and polyhydroxystyrene and its copolymers, are frequently used as resin components in chemically amplified photoresists.

[0007] Based on the operating principle of chemistry amplification photoresists, trace amounts of acidic or alkaline impurities remaining in the photoresist components can interfere with the normal working mechanism of the photoacid generator, preventing normal exposure-development processes and reducing the shelf life of the photoresist. The commonly used synthetic routes for polyhydroxystyrene resins used in photoresists are: 1. Polymerization of monomers such as tert-butoxystyrene and p-(1-ethoxyethoxy)styrene; 2. Deprotection of the synthesized products from the previous step, with catalysts such as hydrochloric acid and sulfuric acid; 3. Partial protection of polyhydroxystyrene, such as alkali-catalyzed tert-butoxycarbonyl protection reactions or Lewis acid-catalyzed addition reactions of vinyl ethers. It is evident that the use of acid catalysts is unavoidable in the synthesis of polyhydroxystyrene resins required for I-line and KrF lines, and their removal is a crucial aspect of resin quality control.

[0008] Methods for removing acidic and alkaline residues and metal ion impurities from photoresist materials have always been a focus of research in the industry. Among the known purification and impurity removal methods, specific acidic and alkaline residues and metal ion impurities are mainly removed through different methods and processes.

[0009] The reported methods can be broadly categorized as follows: 1. Ultrapure water washing, including extraction and resin washing. Due to the extremely high requirements for impurity residue in the semiconductor industry, multiple and repeated water washings are often necessary to achieve the desired result, and additional drying is also required; 2. Purification with anion and cation exchange resins. Depending on the nature and type of impurities to be removed, the anion and cation exchange resins require complex pretreatment to prevent the introduction of other impurities that could contaminate the product during use; 3. Other commonly used adsorbents, such as activated carbon and silica gel, are used to purify resin solutions of impurities such as metals. The effectiveness of different adsorbent solutions depends on parameters such as the type, structure, and pore size of the adsorbent. Their adsorption capacity for different metal and organic impurities varies greatly, and they cannot be well matched to the purification of specific impurities in photoresist resins.

[0010] Silica gel particles are a commonly used industrial material with a highly porous structure, large specific surface area, and good chemical and mechanical stability. They are often used as carriers for adsorbent materials to purify and adsorb impurities such as color and metal ions. Amine functional groups (-NH2, -NH-) have a strong adsorption effect on specific groups and metal ions. Therefore, using silica gel as the matrix carrier and organic compounds containing amine functional groups as modifiers, amine-modified silica gel materials can be prepared that possess both excellent chemical and mechanical stability and a large adsorption capacity for target groups.

[0011] Amine-modified silica materials, formed by modifying and grafting primary, secondary, and tertiary amine functional groups onto the surface of silica gel through synthetic methods, are commonly used in high-purity chemicals for the adsorption, purification, and removal of some low-valent, divalent, and high-valent metal ion impurities. Depending on the different functional groups of the modified material, amine-modified silica materials possess different functions and are widely used in biomedicine, bactericides, and metal ion treatment.

[0012] Similarly, using silica gel as the matrix carrier and organic compounds containing thiol functional groups as modifiers, the prepared thiol-modified silica gel materials also possess excellent chemical and mechanical stability, and are widely used in biomedicine, bactericides, metal ion treatment, etc., especially in the purification of some high-purity chemicals with high requirements for metal ion impurities, to remove low-valence metal ions and heavy metal ions.

[0013] Modified silica-based materials are one of the important emerging functional materials in recent years. These are a class of important new materials synthesized by modifying silica particle matrices. They possess characteristics such as high specific surface area and high adsorption capacity, the ability to modify and graft specific functional groups, adsorption and purification of specific impurities, and convenient separation and recovery. They have already seen many industrial applications, particularly in solid acid catalysis and the adsorption and purification of metal ion impurities. However, most research on silica materials and modified silica materials focuses on aqueous systems and the adsorption of lead, mercury, cadmium, radioactive metal ions, and heavy metal ions. Modified silica materials have rarely been applied in the preparation of semiconductor electronic organic chemical materials, especially in the application of key components such as upstream semiconductor resin materials with extremely high purification requirements.

[0014] 4-Dimethylaminopyridine is a novel, highly efficient basic catalyst widely used in chemical synthesis in recent years. Its structure utilizes the resonance between the electron-donating dimethylamino group and the parent ring (pyridine ring), strongly activating the nitrogen atom on the ring for nucleophilic substitution. It significantly catalyzes acylation (phosphorylation, sulfonylation, and carbonylation) reactions of sterically hindered and low-reactivity alcohols and amines, with an activity approximately 10⁴–6 times that of pyridine. It exhibits high catalytic activity in various types of reactions, including acylation, alkylation, etherification, esterification, and transesterification, in organic synthesis, pharmaceutical synthesis, pesticides, medicines, dyes, fragrances, polymer chemistry, and analytical chemistry.

[0015] Typically, after synthesizing PHS-based resins for 248nm photoresists, the conventional purification process for removing the small-molecule catalyst N,N-dimethylpyridine is cumbersome. Common purification methods include using solid acidic ion exchange resins for slow adsorption and neutralization. However, these solid acidic ion exchange resins require tedious pretreatment to remove soluble small-molecule acidic substances and ensure no other acidic impurities are introduced. Alternatively, water washing extraction can be used, which introduces a high amount of water, requiring subsequent drying of the solution to remove moisture. These conventional methods all result in a significant loss of effective resin.

[0016] Therefore, the catalyst used in the synthesis of PHS-type photoresists—the small organic molecule 4-N,N-dimethylaminopyridine—cannot remain after the reaction is complete. This is because chemically amplified photoresists have strict requirements on the pH value of the resin products used; alkaline and acidic substances must have a residual value of <1 ppm, otherwise it will seriously affect the working principle of the photoacid generator.

[0017] Therefore, after the catalytic synthesis reaction of the resin is completed, the small molecule catalyst 4-N,N-dimethylaminopyridine added during the reaction must be purified and removed separately from the reaction solution system, while other trace amounts of acidic or basic substances should not be introduced to affect the function of the photo-induced acid generator.

[0018] Therefore, it is essential to develop a solid-based alkaline catalyst that can overcome the shortcomings of small-molecule alkaline catalysts, such as small-molecule 4-dimethylaminopyridine, which are difficult to purify and remove after catalytic synthesis, while possessing purification functions similar to other solid metal ion adsorbents.

[0019] In the process of using and researching the functional applications of modified silicone-based materials, it was found that by branching thiol and 4-methylaminopyridine bifunctional groups onto the silicone surface, the unreacted excess small organic molecules adsorbed inside the modified silicone mass can be easily removed by simple washing, resulting in a solid bifunctional modified silicone material free of small molecule impurities. This modified silicone can replace the small-molecule alkaline catalyst 4-N,N-dimethylpyridine. It can also be used to replace catalytic synthesis reactions in the preparation of t-BOC-PHS resin for chemically amplified photoresists.

[0020] Meanwhile, the thiol groups and 4-methylaminopyridine grafted onto the surface of the modified silica matrix, due to their thiol and weakly basic amine functional groups, have the ability to partially purify and adsorb metal ion impurities. During the reaction process, they can remove metal ion impurities in the reaction solution system to <5 ppb. Summary of the Invention

[0021] The purpose of this invention is to propose a modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups, and to apply it to the catalytic synthesis of a class of chemically amplified photoresist resins, as well as the purification of acid and alkali residues and metal ion impurities. This achieves the catalytic synthesis effect of replacing small-molecule 4-N,N-dimethylaminopyridine. After the reaction, simple solid-liquid filtration separation is sufficient to remove the solid catalyst while simultaneously purifying and removing acid and alkali residues and metal ion impurities from the solution. This solves the problems of catalytic synthesis of t-BOC-PHS resin solutions and the purification of alkaline small-molecule catalysts, other acid and alkali residues, and metal ion impurities. Furthermore, this material can be repeatedly used for catalytic reactions and the purification of acid and alkali residues and metal ion impurities after simple reprocessing.

[0022] This invention proposes a modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups and its preparation. The modified silica-based material, containing thiol and 4-methylaminopyridine bifunctional groups grafted onto the silica surface, forms a novel bifunctional modified silica-based material. Its application is also discussed in the catalytic synthesis of a class of chemically amplified photoresist resins and in the purification of acid and alkali residues and the removal of metal ion impurities.

[0023] The novel bifunctional modified silica gel material involved in this invention has not been found to be used in the field of semiconductor electronic chemicals, and there is no modified silica gel-based material that can be used as a synthesis catalyst and also remove acid and alkali residual impurities and purify metal ion impurities.

[0024] To achieve the objectives of this invention, a novel modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups is provided, the chemical structure of which includes one or more of the following structures:

[0025]

[0026]

[0027] in,

[0028] The silicon atom of 4-methylaminopyridine and the trisiloxy group can be linked by one of methylene, ethyl, or propyl groups;

[0029] The modified silica-based materials represented by chemical formulas (Ⅰ), (Ⅱ), and (Ⅲ) contain thiol and 4-methylaminopyridine bifunctional groups. They possess the general physical properties necessary for modified silica, and have similar characteristics to silica materials, such as high mechanical strength and stability to light and heat.

[0030] The modified silica-based materials containing thiol and 4-methylaminopyridine bifunctional groups represented by structural formulas (Ⅰ), (Ⅱ), and (Ⅲ) of the present invention can be used as solid catalysts containing aminopyridine groups to catalyze esterification and acylation, and synthesize small molecule compounds or polymeric compounds with ester groups or acyl groups such as -COO-, -OOC-, and -CON-.

[0031] This invention also provides a method for preparing a silica-based material modified with thiol and 4-methylaminopyridine bifunctional groups, comprising the following chemical preparation steps:

[0032] (1) 3-mercaptopropyltrimethoxysilane, silica gel, toluene, and triethylamine were added to a reaction flask, heated under nitrogen protection and refluxed, and then dried to obtain mercapto-modified silica gel.

[0033]

[0034] (2) 4-methylaminopyridine and 3-chloroalkyltrimethoxysilane form a solid silane coupling agent; then add mercapto-modified silica gel to toluene, heat and reflux the reaction, perform post-treatment, and dry to obtain a silica gel material modified with mercapto and 4-methylaminopyridine bifunctional groups.

[0035]

[0036] In step (1), the mass ratio of 3-mercaptopropyltrimethoxysilane, silica gel, toluene, and triethylamine is 10:20:60:1.

[0037] In step (1), the reaction temperature is 105℃-115℃.

[0038] In step (1), the reaction time is 12-36 hours; preferably 24 hours.

[0039] In step (2), the temperature of the reflux reaction is 105℃-115℃.

[0040] In step (2), the reflux reaction time is 12-36 hours; preferably 24 hours.

[0041] In step (2), the mass ratio of the silane coupling agent to the mercapto-modified silica gel is 1:1 to 1:4; preferably 1:2.

[0042] The present invention also provides the application of the modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups in catalytic acylation and catalytic esterification reactions.

[0043] Silica-based materials modified with thiol and 4-methylaminopyridine bifunctional groups possess both thiol and 4-methylaminopyridine bifunctional groups in their chemical structure, thus exhibiting the chemical properties of thiol functional groups and the basic catalytic properties of aminopyridine. Therefore, one of the properties of silica-based materials modified with thiol and 4-methylaminopyridine bifunctional groups is as a solid basic catalyst to replace small molecule 4-N,N-dimethylaminopyridine, serving as a catalyst for solid-based materials to catalyze the synthesis of small molecule or high-molecular-weight compounds with acyl or ester groups.

[0044] Among the small molecule or polymeric compounds having ester or acyl groups such as -COO-, -OOC-, and -CON-, compounds with the following structures are particularly preferred for catalytic synthesis:

[0045]

[0046] The modified silica-based material of the present invention, containing thiol and 4-methylaminopyridine bifunctional groups, comprises the following steps in its catalytic synthesis reaction and purification process:

[0047] Modified silica gel containing thiol and 4-methylaminopyridine bifunctional groups was added as an alkaline catalyst to catalyze the reaction of PHS and di-tert-butyl dicarbonate to synthesize t-BOC-PHS.

[0048] The chemical materials to be synthesized by catalysis include high or low molecular weight substances containing ester bonds or amides, including m- or cresol-formaldehyde resins, polyhydroxystyrene and its copolymers, and polyacrylic acid derivatives; the chemical materials to be synthesized by catalysis include photoresist resin materials;

[0049] In the application described, the solvent is an organic ether reagent, including ethyl lactate, propylene glycol methyl ether acetate, ethyl acetate, methyl acetate, acetone, toluene, methanol, ethanol, and 4-heptanone.

[0050] This invention also provides the application of modified silica-based materials containing thiol and 4-methylaminopyridine bifunctional groups in the purification and removal of impurities from product solution systems.

[0051] The impurities include metal ion impurities, acidic impurities, and alkaline impurities in the solution.

[0052] The acidic impurities include inorganic acids and organic acids; the inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, formic acid, and oxalic acid; the organic acids include p-toluenesulfonic acid, camphorsulfonic acid, acetic acid, and formic acid.

[0053] The alkaline impurities include organic amines and other alkaline substances;

[0054] The metal ion impurities include metal ion impurities containing metals from periods 4 to 7 and groups 3 to 12, as well as polyvalent metal ions.

[0055] This modified silica-based material, containing thiol and 4-methylaminopyridine bifunctional groups, possesses thiol and amino groups capable of purifying and removing metal ions, effectively removing metal ion impurities from the solution system after the reaction. Therefore, as a solid-based material with basic aminopyridine groups, this modified silica-based material does not introduce small-molecule basic substances that are difficult to purify and remove into the reaction system. Simultaneously, acidic substances in the solution system are naturally neutralized and filtered out by the solid basic groups. This significantly improves the synthesis and purification of photoresist resin-based electronic chemicals with high requirements for reaction and purification.

[0056] The present invention also proposes a catalytic synthesis method for a resin for semiconductor photoresist, wherein the modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups is used as a catalyst in the catalytic synthesis reaction.

[0057] The present invention also proposes a method for removing impurities after the completion of the resin catalytic synthesis reaction, wherein the modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups is added; the impurities include metal ion impurities, acidic impurities, and basic impurities.

[0058] The present invention also proposes a method for using the modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups, the method comprising the following steps:

[0059] The modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups is used as a solid catalyst to carry out catalytic synthesis of acylation or esterification reactions; after the reaction is completed, the solid and liquid are simply separated by a filtration separation device to obtain the desired product solution.

[0060] The modified silica-based material of the present invention, containing difunctional groups of thiol and 4-methylaminopyridine, exhibits improved performance in the purification of solution systems through the following steps:

[0061] After the reaction solution system is complete, only simple filtration is needed to separate the liquid product from the solid modified silica gel material. No other complex purification processes are required.

[0062] The method of the present invention significantly reduces the content of major metal ion impurities in the product solution to below 5 ppb, and can remove small molecule acid and alkali residues in the liquid product to below 1 ppm.

[0063] The beneficial effects of this invention are as follows: The novel modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups proposed in this invention can be prepared using conventional methods. The modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups obtained by this invention exhibits excellent alkaline catalytic acylation and catalytic esterification performance. When using the modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups as a catalyst for catalytic acylation and catalytic esterification reactions, this invention features low catalyst usage, easy filtration and separation, and low metal ion impurity content. It has good applications in the resin-catalyzed synthesis of 248nm photoresists, the removal of acidic and alkaline residual impurities, and the removal of metal ion impurities. Detailed Implementation

[0064] The present invention will be further described below with reference to specific embodiments, but the embodiments below are examples of the present invention and the present invention is not limited to the following embodiments.

[0065] Without departing from the spirit or scope of this invention, the preparation of the modified silica-based materials containing thiol and 4-methylaminopyridine bifunctional groups involved in this invention can be carried out using other publicly available synthetic methods, which will be apparent to those skilled in the art. These synthetic techniques are conventional, and the resulting compounds meet the standards for fine organic electronic chemicals.

[0066] In the following specific examples relating to the catalytic and purification properties of modified silica-based materials containing thiol and 4-methylaminopyridine bifunctional groups, the scope of the claims is not limited to, nor is it limited to, the scope listed in the examples.

[0067] The following shows the preparation of various modified silica-based materials containing thiol and 4-methylaminopyridine bifunctional groups, as well as their application test results in catalytic reactions and impurity purification.

[0068] Example 1: Silica-based materials modified with thiol and 4-methylaminopyridine bifunctional groups

[0069] (1) Preparation of intermediate mercapto-modified silica gel material:

[0070] Add 80g silica gel, 240g toluene, 4g triethylamine, and 40g 3-mercaptopropyltrimethoxysilane to a 1L three-necked flask. Start the stirrer at 200 rpm; purge the system with nitrogen to ensure a nitrogen atmosphere; slightly open the steam heating valve to maintain reflux. React at 110℃ for 24 hours with stirring. Cool to room temperature. Remove the solvent and unreacted raw materials by vacuum filtration until dry.

[0071] Then add 150 ml of ethyl acetate to the 1 L three-necked flask, add the filtered solid and stir for 30 min, then filter (the filtered toluene is stored separately for later recovery); repeat twice.

[0072] Then add 150 ml of ethanol to the 1 L three-necked flask, add the filtered solid and stir for 30 min, then filter; repeat twice to test the ethanol liquid until the maximum impurity is less than 0.02%;

[0073] Then add 150ml of pure water to the 1L three-necked flask, add the filtered solid, stir for 30 minutes, filter, and repeat twice.

[0074] Then add 150 ml of ethanol to the 1 L three-necked flask, add the filtered solid, stir for 30 min, and filter.

[0075] Remove the silica gel, filter and dry it at 80℃ for 12 hours to obtain 100g of the intermediate mercapto-modified silica gel. Store it dry.

[0076] (2) Preparation of silica gel modified with thiol and 4-methylaminopyridine bifunctional groups:

[0077] Add 100g of the intermediate mercapto-modified silica gel prepared in the above steps, 300g of toluene, 5g of triethylamine, and 50g of 3,4-methylaminopyridinetrimethoxysilane to a 1L three-necked reaction flask. Start the stirrer at 200 rpm; purge the system with nitrogen to ensure a nitrogen atmosphere; slightly open the steam heating valve to maintain reflux of the feed solution. React at 110℃ for 48 hours with stirring. Cool to room temperature. Remove the solvent and unreacted raw materials by vacuum filtration until dry.

[0078] Then add 200 ml of ethyl acetate to the 1 L three-necked flask, add the filtered solid and stir for 30 min, then filter (the filtered ethyl acetate is stored together for later recycling); repeat twice.

[0079] Then, add 200 ml of ethanol to the 1 L three-necked flask, add the filtered solid, stir for 30 min, and filter (the filtered ethanol is stored in a centralized manner for later recycling); repeat twice; take the ethanol liquid for testing until the maximum impurity is less than 0.02%; add 200 ml of pure water to the 50 L reactor, add the filtered solid, stir for 30 min, filter, and repeat twice.

[0080] Then add 200 ml of ethanol to the 1 L three-necked flask, add the filtered solid, stir for 30 min, and filter.

[0081] Remove the silica gel and dry it in an oven at 80°C for 12 hours to obtain 130g of modified silica gel-based material containing thiol and 4-methylaminopyridine bifunctional groups. Store in a dry, airtight container.

[0082] Example 2: Catalytic Synthesis Example;

[0083] Take 0.1g of the dried silica-based material modified with thiol and 4-methylaminopyridine bifunctional groups obtained in Example 1 of this invention, add it to a 250mL three-necked reaction flask, then add 100mL of reaction solvent PMA, 25g of solid PHS (polyvinylphenol) powder, and 12g of di-tert-butyl dicarbonate. Under nitrogen protection, react at room temperature for 12 hours, and then stop the reaction to obtain reaction solution 1. Then, take samples to detect the t-BOC-PHS content, the residual amount of di-tert-butyl dicarbonate, and the molecular weight of the resin.

[0084] After the reaction, in a cleanroom under nitrogen protection, the solid-liquid mixture of the product was filtered and separated using a 1µm pore size PTFE microfiltration membrane and filter. Samples were taken for testing of metal ion impurities and amine small molecule impurities; the results are shown in Table 1.

[0085] Example 3:

[0086] 0.015 g of 4-N,N-dimethylaminopyridine was added to a 250 mL three-necked reaction flask, followed by 100 mL of reaction solvent PMA, 25 g of solid PHS (polyvinylphenol) powder, and 12 g of di-tert-butyl dicarbonate. The reaction was carried out under nitrogen protection at room temperature for 12 hours, after which the reaction was terminated, yielding reaction solution 2. Samples were taken to determine the t-BOC-PHS content, residual di-tert-butyl dicarbonate, and resin molecular weight.

[0087] After the reaction, samples were taken and analyzed for metal ion impurities and small amine molecule impurities in a cleanroom under nitrogen protection. Table 1 below shows the product, organic impurities, remaining raw materials, and molecular weight data for the comparative reaction solution (reaction solution 2):

[0088] Table 1

[0089]

[0090] Example 4

[0091] The table below shows the metal ion impurity data of the purified resin product made from the silica-based material modified with thiol and 4-methylaminopyridine bifunctional groups prepared in Example 1 of this invention. The test data are as follows:

[0092] Comparative experiment: Comparison of metal ion impurities in the product solution filtered by the method of this invention with those obtained by other purification methods:

[0093] The present invention relates to a reaction solution catalyzed by a silica-based material modified with thiol and 4-methylaminopyridine bifunctional groups for the synthesis of t-BOC-PHS. This solution was then compared with a reaction solution synthesized using conventional 4-N,N-dimethylaminopyridine catalysis, after several different purification methods to obtain product solutions. The comparisons were made regarding residual alkaline substances and purification data for metal ion impurities.

[0094] The results of residual small molecule amines (GC test) and major metal ion impurities (ICP-MS test) in the original reaction solution and purified resin solution after catalysis with two different catalysts are shown in Table 2 below:

[0095] Table 2

[0096]

[0097]

[0098] Example 5: Comparison of data from other methods for purifying metal ion impurities

[0099] Comparative experiment: Comparison of metal ion impurities in the product solution filtered by the method of this invention with those obtained by other purification methods:

[0100] The present invention relates to a reaction solution catalyzed by a silica-based material modified with thiol and 4-methylaminopyridine bifunctional groups for the synthesis of t-BOC-PHS. This solution was then compared with a reaction solution synthesized using conventional 4-N,N-dimethylaminopyridine catalysis, after several different purification methods to obtain product solutions. The comparisons were made regarding residual alkaline substances and purification data for metal ion impurities.

[0101] The results of residual small molecule amines (GC test) and major metal ion impurities (ICP-MS test) in the original reaction solution and purified resin solution after catalysis with two different catalysts are shown in Table 3 below:

[0102] Table 3

[0103]

[0104] The above embodiments are merely specific examples that are generally representative.

[0105] Although the present invention has been described above with general descriptions and specific embodiments, these are representative examples. Modifications and improvements can be made to the present invention, which will be obvious to those skilled in the art. Therefore, the present invention is not limited to the above description, and modifications or improvements made without departing from the present invention are also within the scope of protection of the present invention.

Claims

1. A modified silica-based material containing a thiol group and a 4-methylaminopyridine bifunctional group, characterized in that: Its structure includes one or more of the following formulas (I), (II), and (III): Equation (I); Equation (II); Formula (III).

2. The method for preparing the modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups as described in claim 1, characterized in that, It can be prepared by the following synthetic methods: a synthetic method of first grafting a thiol group and then grafting a 4-methylaminopyridine functional group, or a synthetic method of simultaneously synthesizing two different chemical functional groups, thiol group and 4-methylaminopyridine, and grafting them onto a silica gel group.

3. The preparation method according to claim 2, characterized in that, The specific steps of the method are as follows: (1) 3-mercaptopropyltrimethoxysilane, silica gel, toluene, and triethylamine were added to a reaction flask, heated under nitrogen protection and refluxed, and then dried to obtain mercapto-modified silica gel. (2) 4-methylaminopyridine and 3-chloroalkyltrimethoxysilane form a solid silane coupling agent; then, thiol-modified silica gel and the silane coupling agent are added to toluene, heated under reflux, post-treated, and dried to obtain a silica gel material modified with thiol and 4-methylaminopyridine bifunctional groups.

4. The preparation method according to claim 3, characterized in that, In step (1), the mass ratio of 3-mercaptopropyltrimethoxysilane, silica gel, toluene, and triethylamine is 10:20:60:1; the reaction temperature is 105℃-115℃; and the reaction time is 12-36 hours. In step (2), the temperature of the reflux reaction is 105℃-115℃; the time of the reflux reaction is 12-36 hours; and the mass ratio of the silane coupling agent to the mercapto-modified silica gel is 1:1-1:

4.

5. The application of the modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups as described in claim 1, characterized in that, It is used as an alkaline catalyst in resin catalytic synthesis reactions; or, after the resin catalytic synthesis reaction is completed, it is used to remove metal ion impurities, acidic impurities, and alkaline impurities from the solution.

6. The application as described in claim 5, characterized in that, In the aforementioned applications, the chemical materials to be synthesized by catalysis include high or low molecular weight substances containing ester bonds or amides, including m-cresol-formaldehyde resin, polyhydroxystyrene and its copolymers, and polyacrylic acid derivatives; the chemical materials to be synthesized by catalysis also include photoresist resin materials. In the aforementioned applications, solvents include ethyl lactate, propylene glycol methyl ether acetate, ethyl acetate, methyl acetate, acetone, toluene, methanol, ethanol, and 4-heptanone.

7. The application as described in claim 5, characterized in that, In the application The acidic impurities include inorganic acids and organic acids; the inorganic acids include hydrochloric acid, sulfuric acid, and nitric acid; the organic acids include p-toluenesulfonic acid, camphorsulfonic acid, acetic acid, formic acid, and oxalic acid. The alkaline impurities include organic amines and other alkaline substances; The metal ion impurities include metal ion impurities containing metals from periods 4 to 7 and groups 3 to 12, as well as polyvalent metal ions.

8. A catalytic synthesis method for a resin used in semiconductor photoresist, characterized in that, In the catalytic synthesis reaction, the modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups as described in claim 1 is used as the catalyst.

9. A method for removing impurities after a resin-catalyzed synthesis reaction is completed, characterized in that, In the method, a modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups as described in claim 1 is added; the impurities include metal ion impurities, acidic impurities, and basic impurities.

10. A method of using the modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups as described in claim 1, characterized in that, The method includes the following steps: The modified silica-based material containing thiol and 4-methylaminopyridine bifunctional groups is used as a solid catalyst to carry out catalytic synthesis of acylation or esterification reactions; after the reaction is completed, the solid and liquid are simply separated by a filtration separation device to obtain the desired product solution.

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