Electronic grade isopropanol purification process for semiconductor wet cleaning

Abstract

The application discloses an electronic-grade isopropyl alcohol purification process for semiconductor wet cleaning, and belongs to the isopropyl alcohol purification field, and specifically comprises the following steps: performing pre-distillation treatment on raw material isopropyl alcohol, taking a middle fraction to obtain pretreated isopropyl alcohol, introducing ultrapure water and electronic-grade carbon dioxide into the pretreated isopropyl alcohol to obtain activated isopropyl alcohol. The application is characterized in that an asymmetric cation conductive membrane with a single-side cation affinity layer and a pore conduction network is constructed, and trace water and carbon dioxide are used to activate isopropyl alcohol, so that metal impurities are directionally migrated to the ultrapure water side under the action of an electric field, thereby realizing efficient removal of trace metal impurities in isopropyl alcohol, reducing the metal content in electronic-grade isopropyl alcohol, and improving the purification efficiency of the electronic-grade isopropyl alcohol.

Description

Technical Field

[0001] This invention relates to the field of isopropanol purification, and more specifically to an electronic-grade isopropanol purification process for semiconductor wet cleaning. Background Technology

[0002] Isopropanol is an important electronic chemical widely used in semiconductor wafer wet cleaning, drying, photoresist removal, surface dehydration, and precision device cleaning processes. As integrated circuit manufacturing processes continue to develop towards smaller linewidths and higher integration levels, the requirements for controlling contaminants such as metal ions, particles, moisture, and dissolved gases on the wafer surface are becoming increasingly stringent. Even trace amounts of metal impurities in isopropanol at extremely low concentrations may remain or be adsorbed on the wafer surface, leading to problems such as gate oxide layer defects, increased leakage current, and decreased device reliability.

[0003] Currently, purification methods for electronic-grade isopropanol typically include processes such as distillation, adsorption, ion exchange, membrane filtration, dehydration, and terminal filtration. Among these, distillation is mainly used to remove moisture and volatile organic impurities, but its ability to remove non-volatile or trace metal impurities is limited. While adsorption and ion exchange methods can remove some metal ions, in low-polarity isopropanol systems, the dissociation degree of metal impurities is low and their migration ability is weak, leading to unstable adsorption or exchange efficiency. Furthermore, there is a risk of adsorbent precipitation, dissolution, or secondary contamination. Conventional microfiltration is mainly used to remove particulate contaminants, but its effectiveness in removing dissolved or complexed metal ions is limited. In addition, during membrane separation processes for removing metal ions from organic solvents, ordinary cation exchange membranes have insufficient wettability, ion conductivity, and interfacial trapping ability in low-polarity media such as isopropanol, making it difficult to effectively capture trace metal ions. Moreover, the membrane migration resistance of metal ions across conventional symmetrical membrane structures is relatively large, easily leading to problems such as low mass transfer efficiency, low removal rate, or back diffusion. Therefore, the removal efficiency of trace metals in isopropanol needs further improvement. Summary of the Invention

[0004] The purpose of this invention is to provide an electronic-grade isopropanol purification process for semiconductor wet cleaning, thereby overcoming the aforementioned technical deficiencies.

[0005] The objective of this invention can be achieved through the following technical solution: an electronic-grade isopropanol purification process for semiconductor wet cleaning, comprising the following steps: S1. The raw material isopropanol is pre-distilled to obtain pre-treated isopropanol by taking the middle fraction. S2. Introduce ultrapure water and electronic-grade carbon dioxide into the pretreated isopropanol to convert the metal impurities in the pretreated isopropanol into hydrated ions or migratable cations to obtain activated isopropanol. S3. Activated isopropanol is introduced into an isolated electroporation module equipped with an asymmetric cation conduction membrane. The asymmetric cation conduction membrane includes a porous support layer, a cation conduction filling phase formed in the pores of the porous support layer, and a cation affinity layer disposed on one side of the asymmetric cation conduction membrane. The activated isopropanol flows through the side close to the cation affinity layer, and ultrapure water flows through the other side of the asymmetric cation conduction membrane. Under the action of an applied pulsed DC electric field, the metal cations in the activated isopropanol are captured by the cation affinity layer, conducted by the cation conduction filling phase, and migrate to the ultrapure water side to obtain purified isopropanol. S4. The purified isopropanol is subjected to activation medium stripping, moisture restoration and particulate metal blocking treatment to obtain electronic grade isopropanol for semiconductor wet cleaning.

[0006] Further, in step S1, the preparation method of pretreated isopropanol is as follows: the raw material isopropanol is filtered through a filter medium with a pore size of 0.05-0.20 μm, and then fed into a distillation column with 30-40 trays under nitrogen protection. It is stabilized under total reflux for 20-30 min. Then, the fore fraction, which accounts for 3-5 vol% of the volume of the raw material isopropanol, is removed at a reflux ratio of 10-16:1. Then, the middle fraction, which accounts for 85-90 vol% of the volume of the raw material isopropanol, is collected at a reflux ratio of 5-7:1. The middle fraction is cooled under nitrogen protection to obtain pretreated isopropanol.

[0007] Further, in step S2, the method for preparing activated isopropanol is as follows: pretreated isopropanol is fed into a static mixer, electronic-grade ultrapure water is added to the static mixer to adjust the water content in the isopropanol to 400-600 ppm, and then electronic-grade carbon dioxide is dissolved at 25-28℃ and 0.4-0.5 MPa to make the dissolved carbon dioxide content in the isopropanol 1000-1300 ppm. The mixed isopropanol is then placed in a residence tube and left to stand for 12 min to obtain activated isopropanol.

[0008] Furthermore, in step S3, the isolated electroporation module is divided into an isopropanol channel and an ultrapure water channel by an asymmetric cation conduction membrane; The isopropanol channel is located on the side of the asymmetric cation-conducting membrane near the cation affinity layer. The effective width of the isopropanol channel is 180-200 mm, and the flow rate of isopropanol in the isopropanol channel is 1.1-1.4 L / min. The ultrapure water flow channel is located on the side of the asymmetric cation conduction membrane away from the cation affinity layer. The effective width of the ultrapure water flow channel is 180-200 mm, and the flow rate of ultrapure water in the ultrapure water flow channel is 0.7-0.8 L / min. The applied pulsed DC electric field strength is 16-20V / cm, with a cycle of 8-10s for power-on and 1-2s for power-off, and continuous processing for 30-40min.

[0009] Further, in step S4, the preparation method of electronic-grade isopropanol is as follows: purified isopropanol is passed into a degassing membrane contactor at a flow rate of 6-8 L / min for circulating degassing treatment until there are no visible microbubbles in the isopropanol, dissolved oxygen is below 0.5 mg / L, and dissolved carbon dioxide is below 20 ppm. The degassed isopropanol and molecular sieve are mixed at a liquid-solid ratio of 10:1, dried and dehydrated until the moisture content is below 45 ppm, and then filtered using a PTFE terminal filter with a pore size of 0.02-0.05 μm to obtain the finished electronic-grade isopropanol.

[0010] Furthermore, the asymmetric cation-conducting membrane is obtained by the following steps: A1. Select ePTFE porous membrane as porous support layer. Clean the ePTFE porous membrane sequentially with electronic grade isopropanol, 60℃ ultrapure water and 0.01mol / L electronic grade nitric acid solution. Then rinse with ultrapure water until the conductivity of the cleaning solution is less than 1μS / cm. Finally, replace the water with electronic grade isopropanol and blow dry with high-purity nitrogen to obtain pretreated porous membrane. A2. Placing the pretreated porous membrane in an Ar / O2 mixed atmosphere for plasma activation treatment, resulting in an ion-activated porous membrane; A3. The ion-activated porous membrane is placed in a solution containing fluorosulfonic acid ionomer and subjected to vacuum impregnation, drying and heat treatment, so that the fluorosulfonic acid ionomer solution forms a cationic conductive filling phase in the pores of the ion-activated porous membrane, thus obtaining a filled porous membrane. A4. One side of the filled porous membrane is shielded, and the other side is coated with grafting solution. Then, it is placed in a drying oven at a temperature of 60-70℃ and dried to constant weight. The shielding is removed, and a cation affinity layer is formed on one side of the filled porous membrane to obtain an asymmetric cation conduction membrane.

[0011] Furthermore, in step A2, during the plasma activation treatment, the Ar flow rate is 60-80 sccm, the O2 flow rate is 18-22 sccm, the treatment power is 120W, and the treatment time in the plasma is 90-110s; in step A4, the coating amount of the grafting solution is 5-7 g / m².

[0012] Further, in step A3, the method for preparing the fluorosulfonic acid ionomer solution is as follows: 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate sodium, 2-hydroxyethanephosphonic acid, polyethylene glycol-400, ethylene glycol diglycidyl ether, isopropanol, and ultrapure water are mixed evenly in a ratio of 2-3g:0.5-0.7g:1.6-2.2g:1-1.4g:18-20mL:75-80mL to obtain the fluorosulfonic acid ionomer solution.

[0013] Furthermore, the vacuum impregnation, drying, and heat treatment include: placing the ion-activated porous membrane in a solution containing fluorosulfonic acid ionomer, vacuum impregnating the reaction system for 5-7 minutes after drawing a negative pressure, then restoring it to normal pressure, letting it stand for 10-15 minutes, removing the membrane material, drying it at 65-75℃ for 30-40 minutes, and then heat-treating it at 150-160℃ for 25-35 minutes. The above operation is repeated 3 times to obtain a filled porous membrane.

[0014] Further, in step A4, the grafting solution is prepared as follows: aminomethylphosphonic acid, disodium iminodiacetic acid, 2-hydroxymethyl-15-crown-5, purified water and ethanol are mixed and stirred until the system is dissolved. 3-glycidyl etheroxypropyltrimethoxysilane is added to the reaction system. The reaction system is heated to 50-60℃ and kept at this temperature for 30-50 min. The system is then allowed to cool naturally to room temperature to obtain the grafting solution.

[0015] Furthermore, the molar ratio of aminomethylphosphonic acid, disodium iminodiacetate, 2-hydroxymethyl-15-crown-5,3-glycidyl etheroxypropyltrimethoxysilane is 0.5:1.5:0.3:2.5, and the volume ratio of disodium iminodiacetate, purified water, and ethanol is 1g:7mL:2mL.

[0016] The present invention has the following beneficial effects: This invention pretreats the raw material isopropanol through distillation to remove volatile impurities and reduce the non-volatile metal load. Then, by adjusting the mixture with trace amounts of ultrapure water and electronic-grade carbon dioxide, metal salts, adsorbed metals, or trace oxides in the low-polarity isopropanol system are more easily converted into hydrated or migratable ions, improving its responsiveness under an applied electric field. Subsequently, in an isolated electroporation module, activated isopropanol flows through the cation affinity layer of an asymmetric cation-conducting membrane, and under the action of a pulsed electric field, metal cations are directionally migrated to the ultrapure water channel, where they are then transported by ultrapure water. The continuous removal of carbon dioxide, dissolved oxygen, microbubbles, moisture, and particulate contaminants maintains the concentration gradient and alleviates concentration polarization on the membrane surface. Subsequent degassing, molecular sieve drying, and terminal filtration remove carbon dioxide, dissolved oxygen, microbubbles, moisture, and particulate contaminants, respectively, avoiding secondary impacts on the final product from the preceding activation medium or solid desiccant. While ensuring low moisture, low particle content, and detection stability of electronic-grade isopropanol, it achieves efficient removal of various metal ions such as Na, K, Ca, Mg, Fe, Cu, Ni, and Cr, reducing their concentration to the ppt level and exhibiting a high removal rate, thus meeting the contamination control requirements of semiconductor wet cleaning.

[0017] This invention also cleans the ePTFE porous membrane to remove organic residues, water-soluble ions, and metallic impurities from the membrane pores and surface. Further activation via Ar / O2 plasma introduces polar oxygen-containing groups onto the inert ePTFE pore wall surface, forming a micro-roughened interface. This enhances the wetting, penetration, and fixation effects of the fluorosulfonic acid, phosphonic acid, polyether, and epoxy crosslinking system on the micropores. The subsequently formed intrapore crosslinked filling network and porous support framework form a stable, interconnected ion-conducting phase, allowing functional sites such as sulfonates, phosphonic acids, and polyether oxygen to be continuously distributed within the membrane pores. This provides a stable channel for the selective adsorption, coordination, and migration of metal cations such as Na, K, Ca, Mg, Fe, Cu, Ni, and Cr.

[0018] This invention also involves treating one side of a packed porous membrane with a grafting solution of aminomethylphosphonic acid, disodium iminodiacetic acid, 2-hydroxymethyl-15-crown-5, and a silane coupling agent. This forms a cationic affinity layer rich in phosphonic acid groups, carboxyl groups, amino groups, and crown ether structures on the side near the isopropanol channel. In this cationic affinity layer, the phosphonic acid groups and carboxyl groups can chelate or coordinate with multivalent and transition metals, the crown ether structures and polyether segments can coordinate with alkali metal ions, and the sulfonate groups provide fixed anions. The exchange sites form metal ion enrichment inlets on the isopropanol side, while the membrane-filled network acts as a cation migration channel. The ultrapure water side serves as the metal ion migration and elution outlet, thus forming an asymmetric separation path of interfacial capture, intramembrane conduction, and aqueous phase transfer. This reduces the interfacial mass transfer resistance of trace metal ions under low concentration conditions, reduces non-selective permeation and back diffusion, and allows the chemical affinity of the membrane material to work in conjunction with the electric field driving effect, thereby improving the capture efficiency and transmembrane transfer efficiency of trace metal ions on the isopropanol side. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] In this invention, the ePTFE porous membrane has a thickness of 50-60 μm, an average pore size of 0.08-0.15 μm, and a porosity of 65-75%. In this application, the polyethylene glycol is designated as PEG-400. Example 1

[0021] This embodiment provides a process for preparing an asymmetric cation-conducting membrane, including the following steps: Step 1: Preparation of pretreated porous membrane The ePTFE porous membrane was sequentially cleaned with electronic-grade isopropanol, 60℃ ultrapure water, and 0.01mol / L electronic-grade nitric acid solution, then rinsed with ultrapure water until the conductivity of the cleaning solution was less than 1μS / cm. Finally, the water was replaced with electronic-grade isopropanol and dried with high-purity nitrogen to obtain the pretreated porous membrane.

[0022] In the process of treating ePTFE porous membranes, ePTFE porous membranes with good resistance to isopropanol and chemical corrosion, stable pore structure, and good mechanical strength are selected as the support layer. During the processing, storage, and transportation of the membrane material, organic pollutants, water-soluble ions, metal salts, or trace metal particles may remain. Therefore, a purification pretreatment is required. Electronic-grade isopropanol cleaning can dissolve and remove organic residues and oily impurities from the membrane pores and surface. Cleaning with 60℃ ultrapure water can promote the diffusion of water-soluble salts and polar residues from the pores. 0.01mol / L electronic-grade nitric acid solution can convert some metal oxides, metal hydroxides, or metal salts into more soluble nitrate forms. Then, ultrapure water is used to rinse until the conductivity of the cleaning solution is less than 1μS / cm to remove soluble metal impurities. Finally, electronic-grade isopropanol is used to replace the water and high-purity nitrogen is used to dry the membrane to reduce the introduction of water spots, particles, and metal dust from the air, and to prevent the membrane material from releasing metal impurities into the system during the subsequent isopropanol purification process.

[0023] Step 2: Preparation of ion-activated porous membranes The pretreated porous membrane was placed in a plasma processor, and an Ar / O2 mixed gas was introduced into the plasma processing chamber. The Ar flow rate was set to 60 sccm, the O2 flow rate to 18 sccm, the processing power to 120 W, and the plasma processing time to 90 s. The plasma activation treatment yielded an ion-activated porous membrane.

[0024] During the ion-activated porous membrane treatment, Ar plasma physically bombards and micro-etches the ePTFE surface, forming free radical sites and increasing micro-roughness on the membrane surface. O2 plasma provides oxygen free radicals, oxygen ions, and excited oxygen species, which further transform the free radicals on the membrane surface into polar oxygen-containing groups such as hydroxyl, carbonyl, carboxyl, and peroxy groups, enabling the inert ePTFE pore walls to have subsequent filling and bonding capabilities.

[0025] Step 3: Preparation of filled porous membrane Weigh out 20g of sodium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate, 5g of 2-hydroxyethanephosphonic acid, 16g of polyethylene glycol, 10g of ethylene glycol diglycidyl ether, 180mL of isopropanol and 750mL of ultrapure water and add them to the reaction flask. Stir until the system is dissolved to obtain a fluorosulfonic acid ionomer solution. Immerse the ion-activated porous membrane in a solution containing fluorosulfonic acid ionomer, apply a negative pressure to -0.08 MPa, maintain vacuum impregnation for 5 min, then restore normal pressure, let stand for 10 min, remove the membrane, dry it at 65℃ for 30 min, and then heat treat it at 150℃ for 25 min. Repeat the above operation 3 times to obtain a filled porous membrane.

[0026] In the preparation of the packed porous membrane, vacuum impregnation allows the fluorosulfonic acid ionomer solution to fully penetrate the depth of the pores. After restoring atmospheric pressure, external pressure further propels the solution to fill the micropores. In the fluorosulfonic acid ionomer solution, sodium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate provides fluorinated segments, hydroxyl groups, and sulfonate groups. The fluorinated segments are beneficial for improving the compatibility of the packed phase with the ePTFE support layer and isopropanol medium, while the sulfonate groups act as fixed anion sites to attract and conduct metal cations. 2-hydroxyethanephosphonic acid provides phosphonic acid groups and hydroxyl groups. The phosphonic acid groups attract multivalent metal cations such as Ca, Mg, Fe, and Cr. Metal or hard acid-type metal ions have strong coordination effects; polyethylene glycol provides flexible polyether segments, whose ether oxygen atoms can assist in the coordination of alkali metal ions such as Na and K through ion-dipole interactions, and improve the solvation migration environment of metal ions in the membrane; ethylene glycol diglycidyl ether contains diepoxy groups, which can undergo epoxy ring-opening reactions with hydroxyl groups, acidic hydroxyl groups or other nucleophilic groups in the system under heat treatment conditions to generate β-hydroxy ether structures, and crosslink and fix the above functional components in the membrane pores to form cation-selective migration channels, enabling metal ions to migrate continuously along fixed anion sites and coordination sites under the action of an electric field.

[0027] Step 4: Preparation of asymmetric cation-conducting membrane Weigh out 5.6 g of aminomethylphosphonic acid, 26.6 g of disodium iminodiacetate, 7.5 g of 2-hydroxymethyl-15-crown-5, 186.2 mL of purified water and 53.2 mL of ethanol and add them to the reaction flask. Stir until the system is dissolved. Add 59.1 g of 3-glycidyl etheroxypropyltrimethoxysilane to the reaction flask. Heat the reaction flask to 50 °C and keep it at that temperature for 30 min. Let it cool naturally to room temperature to obtain the grafting solution. One side of the filled porous membrane was shielded, and the other side was treated with 5 g / m³. 2 The grafting solution was coated with a certain amount of coating solution, and then placed in a drying oven at 60°C to dry to constant weight. The shielding was removed, and a cation affinity layer was formed on one side of the filled porous membrane. The prepared membrane material was then placed in ultrapure water at 50°C, and a DC electric field of 10V / cm was applied to both sides of the membrane material for purification treatment for 120 minutes to obtain an asymmetric cation conduction membrane.

[0028] In the grafting solution used in the preparation of asymmetric cation-conducting membranes, aminomethylphosphonic acid contains amino and phosphonic acid groups, disodium iminodiacetate contains imino and carboxyl salt coordinating groups, 2-hydroxymethyl-15-crown-5 contains a crown ether ring and hydroxymethyl, and 3-glycidyl etheroxypropyltrimethoxysilane contains both epoxy and trimethoxysilyl groups. In the water / ethanol system, the trimethoxysilyl group can undergo hydrolysis to generate silanols, which further condense to form a Si-O-Si network. These silanols can then react with hydroxyl and oxygen-containing groups on the membrane surface or in the network. Condensation or hydrogen bonding occurs; simultaneously, the epoxy groups in the silane molecules attack amino, imino, or hydroxyl groups to undergo epoxy ring-opening reactions, thereby fixing phosphonate, carboxylate, amino, and crown ether structures on one side of the membrane surface and in the near-surface pores. Phosphonate and carboxylate groups can coordinate or chelate with polyvalent metal ions such as Fe, Cu, Ni, Cr, Ca, and Mg; crown ether structures and polyether oxygen segments can coordinate and enrich alkali metal ions such as Na and K through ether oxygen atoms; sulfonate groups provide cation exchange and fix anion conduction sites. Since this affinity layer is located only on one side of the membrane, when it faces the isopropanol channel in the electroporation module, metal ions are first enriched and captured on the isopropanol side, then enter the intramembrane cation conduction network, and finally migrate to the ultrapure water side. This reduces the interfacial mass transfer resistance of trace metal ions under low concentration conditions, reduces non-selective permeation and back diffusion, and improves the final metal removal rate. Example 2

[0029] This embodiment provides a process for preparing an asymmetric cation-conducting membrane, including the following steps: Step 1: Preparation of pretreated porous membrane The ePTFE porous membrane was sequentially cleaned with electronic-grade isopropanol, 60℃ ultrapure water, and 0.01mol / L electronic-grade nitric acid solution, then rinsed with ultrapure water until the conductivity of the cleaning solution was less than 1μS / cm. Finally, the water was replaced with electronic-grade isopropanol and dried with high-purity nitrogen to obtain the pretreated porous membrane.

[0030] Step 2: Preparation of ion-activated porous membranes The pretreated porous membrane was placed in a plasma processor, and an Ar / O2 mixed gas was introduced into the plasma processing chamber. The Ar flow rate was set to 70 sccm, the O2 flow rate to 20 sccm, the processing power to 120 W, and the plasma processing time to 100 s. The plasma activation treatment yielded an ion-activated porous membrane.

[0031] Step 3: Preparation of filled porous membrane Weigh out 25g of sodium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate, 6g of 2-hydroxyethanephosphonic acid, 19g of polyethylene glycol, 12g of ethylene glycol diglycidyl ether, 190mL of isopropanol and 775mL of ultrapure water and add them to the reaction flask. Stir until the system is dissolved to obtain a fluorosulfonic acid ionomer solution. Immerse the ion-activated porous membrane in a solution containing fluorosulfonic acid ionomer, apply a negative pressure to -0.08 MPa, maintain vacuum impregnation for 6 min, then restore normal pressure, let stand for 13 min, remove the membrane, dry it at 70℃ for 35 min, and then heat treat it at 155℃ for 30 min. Repeat the above operation 3 times to obtain a filled porous membrane.

[0032] Step 4: Preparation of asymmetric cation-conducting membrane Weigh out 5.6 g of aminomethylphosphonic acid, 26.6 g of disodium iminodiacetate, 7.5 g of 2-hydroxymethyl-15-crown-5, 186.2 mL of purified water and 53.2 mL of ethanol and add them to the reaction flask. Stir until the system is dissolved. Add 59.1 g of 3-glycidyl etheroxypropyltrimethoxysilane to the reaction flask. Heat the reaction flask to 55 °C and keep it at that temperature for 40 min. Let it cool naturally to room temperature to obtain the grafting solution. One side of the filled porous membrane was shielded, and the other side was treated with 6 g / m³. 2 The grafting solution was coated with a certain amount of coating solution, and then placed in a drying oven at 65°C to dry to constant weight. The shielding was removed, and a cation affinity layer was formed on one side of the filled porous membrane. The prepared membrane material was then placed in ultrapure water at 55°C, and a DC electric field of 10V / cm was applied to both sides of the membrane material for purification treatment for 140 minutes to obtain an asymmetric cation conduction membrane. Example 3

[0033] This embodiment provides a process for preparing an asymmetric cation-conducting membrane, including the following steps: Step 1: Preparation of pretreated porous membrane The ePTFE porous membrane was sequentially cleaned with electronic-grade isopropanol, 60℃ ultrapure water, and 0.01mol / L electronic-grade nitric acid solution, then rinsed with ultrapure water until the conductivity of the cleaning solution was less than 1μS / cm. Finally, the water was replaced with electronic-grade isopropanol and dried with high-purity nitrogen to obtain the pretreated porous membrane.

[0034] Step 2: Preparation of ion-activated porous membranes The pretreated porous membrane was placed in a plasma processor, and an Ar / O2 mixed gas was introduced into the plasma processing chamber. The Ar flow rate was set to 80 sccm, the O2 flow rate to 22 sccm, the processing power to 120 W, and the plasma processing time to 110 s. The plasma activation treatment yielded an ion-activated porous membrane.

[0035] Step 3: Preparation of filled porous membrane Weigh out 30g of sodium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate, 7g of 2-hydroxyethanephosphonic acid, 22g of polyethylene glycol, 14g of ethylene glycol diglycidyl ether, 200mL of isopropanol, and 800mL of ultrapure water, add them to a reaction flask and stir until the system is dissolved to obtain a fluorosulfonic acid ionomer solution. Immerse the ion-activated porous membrane in a solution containing fluorosulfonic acid ionomer, apply a negative pressure to -0.08 MPa, maintain vacuum impregnation for 7 min, then restore normal pressure, let stand for 15 min, remove the membrane, dry it at 75℃ for 40 min, and then heat treat it at 160℃ for 35 min. Repeat the above operation 3 times to obtain a filled porous membrane.

[0036] Step 4: Preparation of asymmetric cation-conducting membrane Weigh out 5.6 g of aminomethylphosphonic acid, 26.6 g of disodium iminodiacetate, 7.5 g of 2-hydroxymethyl-15-crown-5, 186.2 mL of purified water and 53.2 mL of ethanol and add them to the reaction flask. Stir until the system is dissolved. Add 59.1 g of 3-glycidyl etheroxypropyltrimethoxysilane to the reaction flask. Heat the reaction flask to 60 °C and keep it at that temperature for 50 min. Let it cool naturally to room temperature to obtain the grafting solution. One side of the filled porous membrane was shielded, and the other side was treated with 7 g / m³. 2 The grafting solution was coated with a certain amount of coating solution, and then placed in a drying oven at 70°C to dry to constant weight. The shielding was removed, and a cation affinity layer was formed on one side of the filled porous membrane. The prepared membrane material was then placed in ultrapure water at 60°C, and a DC electric field of 10V / cm was applied to both sides of the membrane material for purification treatment for 160 minutes to obtain an asymmetric cation conduction membrane. Example 4

[0037] This embodiment provides an electronic-grade isopropanol purification process for semiconductor wet cleaning, including the following steps: Step 1: Preparation of pretreated isopropanol The raw material isopropanol was filtered through a filter cloth with a pore size of 0.05-0.20 μm and then fed into a distillation column with 30 trays under nitrogen protection. It was stabilized under total reflux for 20 min. Then, the fore fraction, which accounts for 3 vol% of the volume of the raw material isopropanol, was removed at a reflux ratio of 10:1. The middle fraction, which accounts for 85 vol% of the volume of the raw material isopropanol, was collected at a reflux ratio of 5:1. The middle fraction was cooled under nitrogen protection to obtain pretreated isopropanol.

[0038] In the pretreatment process of isopropanol preparation, the raw isopropanol is first filtered through a 0.05-0.20μm filter medium to remove suspended particles, metal particles, colloidal impurities, and any mechanical impurities that may be entrained. The filtered isopropanol is then fed into a nitrogen-protected distillation column. After stabilization under total reflux conditions, the gas-liquid balance within the column is fully established, ensuring the stability of subsequent fraction cutting. The fore-fraction is removed, carrying away low-boiling-point volatile impurities, light components, and some dissolved gases. The middle fraction is collected, avoiding impurities enriched in the fore- and post-fractions. Most metal impurities and low-volatility pollutants remain in the column bottom or high-boiling residue during distillation, reducing the metal load on the subsequent electromigration module and minimizing contamination or site occupancy of the asymmetric cation exchange membrane by particles and high-load metal impurities. This allows subsequent electromigration purification to primarily target low-concentration, migratable trace metal ions.

[0039] Step 2: Preparation of activated isopropanol Pretreated isopropanol was fed into a static mixer, and electronic-grade ultrapure water was added to the static mixer to adjust the water content of the isopropanol to 400 ppm. Then, electronic-grade carbon dioxide was dissolved at 25°C and 0.45 MPa to bring the dissolved carbon dioxide concentration in the isopropanol to 1000 ppm. The mixed isopropanol was then placed in a residence tube and the residence time was 12 min to obtain activated isopropanol.

[0040] In the preparation of activated isopropanol, electronic-grade ultrapure water is added to the pretreated isopropanol. The introduction of trace amounts of water makes it easier for metal ions to form hydrated ions, increases the degree of salt dissociation, and increases the conductivity of the system. This facilitates the capture of metal cations by the affinity layer on the membrane surface and their directional migration in the electric field. The dissolution of electronic-grade carbon dioxide and the trace amounts of water in the system form a weakly acidic environment, which promotes the conversion of some metal oxides, hydroxides, or adsorbed metals into migratory ionic forms and inhibits the deposition of metals on the membrane surface in the form of hydroxides or colloids. The mixed isopropanol enters the residence tube and stays for a period of time, allowing water, carbon dioxide, isopropanol, and trace metal impurities to come into full contact and reach a relatively stable species balance. This makes it compatible with the cation capture and electric field migration functions of the subsequent asymmetric cation conduction membrane, thereby improving the removal rate of trace metal impurities.

[0041] Step 3: Preparation of purified isopropanol The asymmetric cation-conducting membrane prepared in Example 1 was installed in the isolated electroporation membrane migration module. The isolated electroporation membrane migration module was divided into an isopropanol channel with an effective width of 180 mm and an ultrapure water channel with an effective width of 180 mm. The isopropanol channel was located on the side of the asymmetric cation-conducting membrane close to the cation affinity layer. Activated isopropanol was introduced into the isopropanol channel, and the isopropanol flow rate was set to 1.1 L / min. Ultrapure water was introduced into the ultrapure water channel, and the ultrapure water flow rate was set to 0.7 L / min. An external battery was added to the isolated electroporation module, the external electric field strength was set to 16V / cm, and a cycle of 8s on and 1s off was set. After continuous processing for 30 minutes, isopropanol flowed out through the isopropanol channel to obtain purified isopropanol.

[0042] In the purification process of isopropanol, an asymmetric cation exchange membrane divides the module into an isopropanol channel and an ultrapure water channel, with the isopropanol channel located on the side closest to the cation affinity layer. The metal cations in the activated isopropanol first contact the cation affinity layer and are captured and enriched by phosphonate groups, carboxylates, amines, crown ether structures, sulfonate groups, and polyether oxygen sites. Subsequently, under the action of an applied electric field of 16-20 V / cm, the metal cations migrate to the ultrapure water side along the fixed anion sites and coordination conduction channels within the membrane. After migrating to the ultrapure water side, they are carried away by the continuously flowing ultrapure water, thereby maintaining the concentration gradient across the membrane and reducing back diffusion.

[0043] This electroporation process combines chemical affinity and electric field driving. Chemical affinity increases the enrichment probability of trace metal ions on the isopropanol side, while electric field driving ensures that the captured metal ions do not remain on the membrane surface or inside the membrane, but continue to migrate towards the aqueous phase and be discharged from the system, thus avoiding the problems of limited capacity and easy saturation of traditional adsorption methods. The periodic operation of 8-10s of energization and 1-2s of de-energization can alleviate concentration polarization, local heating, bubble accumulation and interface ion depletion that may occur under continuous electric field. The de-energization interval is conducive to the re-diffusion and replenishment of metal ions in the boundary layer, so that the migration efficiency is maintained at a high level in the subsequent energization stage.

[0044] Step 4: Preparation of electronic-grade isopropanol Purified isopropanol is circulated and degassed at a flow rate of 6 L / min through a degassing membrane contactor until no visible microbubbles are found in the isopropanol, dissolved oxygen is below 0.5 mg / L, and dissolved carbon dioxide is below 20 ppm. The degassed isopropanol is then mixed with molecular sieves at a liquid-to-solid ratio of 10:1, dried until the moisture content is below 45 ppm, and then filtered using a PTFE terminal filter with a pore size of 0.02-0.05 μm to obtain electronic-grade isopropanol. Example 5

[0045] This embodiment provides an electronic-grade isopropanol purification process for semiconductor wet cleaning, including the following steps: Step 1: Preparation of pretreated isopropanol The raw isopropanol was filtered through a filter cloth with a pore size of 0.05-0.20 μm and then fed into a 35-plate distillation column under nitrogen protection. The column was stabilized under total reflux for 25 min. Subsequently, the fore fraction, which accounted for 4 vol% of the raw isopropanol volume, was removed at a reflux ratio of 13:1. Then, the middle fraction, which accounted for 87 vol% of the raw isopropanol volume, was collected at a reflux ratio of 6:1. The middle fraction was cooled under nitrogen protection to obtain pretreated isopropanol.

[0046] Step 2: Preparation of activated isopropanol Pretreated isopropanol was fed into a static mixer, and electronic-grade ultrapure water was added to the static mixer to adjust the water content of the isopropanol to 500 ppm. Then, electronic-grade carbon dioxide was dissolved at 25°C and 0.45 MPa to bring the dissolved carbon dioxide concentration in the isopropanol to 1150 ppm. The mixed isopropanol was then introduced into a residence tube and the residence time was 12 min to obtain activated isopropanol.

[0047] Step 3: Preparation of purified isopropanol The asymmetric cation conduction membrane prepared in Example 2 was installed in the isolated electroporation membrane migration module. The isolated electroporation membrane migration module was divided into an isopropanol channel with an effective width of 190 mm and an ultrapure water channel with an effective width of 190 mm. The isopropanol channel was located on the side of the asymmetric cation conduction membrane close to the cation affinity layer. Activated isopropanol was introduced into the isopropanol channel, and the isopropanol flow rate was set to 1.25 L / min. Ultrapure water was introduced into the ultrapure water channel, and the ultrapure water flow rate was set to 0.75 L / min. An external battery was added to the isolated electroporation module, and the external electric field strength was set to 18V / cm. One cycle consisted of 9s of power-on and 1.5s of power-off. The process was carried out continuously for 35 minutes. Isopropanol was then discharged through the isopropanol channel to obtain purified isopropanol.

[0048] Step 4: Preparation of electronic-grade isopropanol Purified isopropanol is circulated and degassed at a flow rate of 7 L / min through a degassing membrane contactor until no visible microbubbles are found in the isopropanol, dissolved oxygen is below 0.5 mg / L, and dissolved carbon dioxide is below 20 ppm. The degassed isopropanol is then mixed with molecular sieves at a liquid-to-solid ratio of 10:1, dried and dehydrated until the moisture content is below 45 ppm, and then filtered using a PTFE terminal filter with a pore size of 0.02-0.05 μm to obtain electronic-grade isopropanol. Example 6

[0049] This embodiment provides an electronic-grade isopropanol purification process for semiconductor wet cleaning, including the following steps: Step 1: Preparation of pretreated isopropanol The raw material isopropanol was filtered through a filter cloth with a pore size of 0.05-0.20 μm and then fed into a distillation column with 40 trays under nitrogen protection. It was stabilized under total reflux for 30 min. Then, the fore fraction, which accounts for 5 vol% of the volume of the raw material isopropanol, was removed at a reflux ratio of 16:1. The middle fraction, which accounts for 90 vol% of the volume of the raw material isopropanol, was collected at a reflux ratio of 7:1. The middle fraction was cooled under nitrogen protection to obtain pretreated isopropanol.

[0050] Step 2: Preparation of activated isopropanol Pretreated isopropanol was fed into a static mixer, and electronic-grade ultrapure water was added to the static mixer to adjust the water content of the isopropanol to 600 ppm. Then, electronic-grade carbon dioxide was dissolved at 25°C and 0.45 MPa to bring the dissolved carbon dioxide concentration in the isopropanol to 1300 ppm. The mixed isopropanol was then placed in a residence tube and the residence time was 12 min to obtain activated isopropanol.

[0051] Step 3: Preparation of purified isopropanol The asymmetric cation-conducting membrane prepared in Example 3 was installed in the isolated electroporation membrane migration module. The isolated electroporation membrane migration module was divided into an isopropanol channel with an effective width of 200 mm and an ultrapure water channel with an effective width of 200 mm. The isopropanol channel was located on the side of the asymmetric cation-conducting membrane close to the cation affinity layer. Activated isopropanol was introduced into the isopropanol channel, and the isopropanol flow rate was set to 1.4 L / min. Ultrapure water was introduced into the ultrapure water channel, and the ultrapure water flow rate was set to 0.8 L / min. An external battery was added to the isolated electroporation module, and the external electric field strength was set to 20V / cm. One cycle was 10s of power-on and 2s of power-off. The process was carried out continuously for 40 minutes. Isopropanol was then discharged through the isopropanol channel to obtain purified isopropanol.

[0052] Step 4: Preparation of electronic-grade isopropanol Purified isopropanol is circulated and degassed at a flow rate of 8 L / min through a degassing membrane contactor until no visible microbubbles are found in the isopropanol, dissolved oxygen is below 0.5 mg / L, and dissolved carbon dioxide is below 20 ppm. The degassed isopropanol is then mixed with molecular sieves at a liquid-to-solid ratio of 10:1, dried and dehydrated until the moisture content is below 45 ppm, and then filtered using a PTFE terminal filter with a pore size of 0.02-0.05 μm to obtain electronic-grade isopropanol.

[0053] Comparative Example 1 The difference between this comparative example and Example 6 is that, in the preparation process of the asymmetric cation-conducting membrane, step 3 is omitted, and the ion-activated porous membrane prepared in step 2 is used instead of the filled porous membrane in step 4.

[0054] Comparative Example 2 The difference between this comparative example and Example 6 is that step 4 is omitted in the preparation process of the asymmetric cation conducting membrane, and the filled porous membrane prepared in step 3 is used as the asymmetric cation conducting membrane.

[0055] Comparative Example 3 The difference between this comparative example and Example 6 is that step two is omitted, and the pretreated isopropanol prepared in step one is used instead of the activated isopropanol in step three.

[0056] Performance testing: The concentrations of Na, K, Ca, Mg, Fe, Cu, Ni, and Cr in the electronic-grade isopropanol samples prepared in Examples 7-9 and Comparative Examples 1-3 were determined according to standard SJ / T 11637-2016 "General Rules for Inductively Coupled Plasma Mass Spectrometry of Electronic Chemicals", and the results were obtained by referring to the formula. The metal removal rate was determined using the formula, where C0 is the concentration of metal in the raw material isopropanol and C1 is the concentration of metal in the electronic grade isopropanol product. Specific test data are shown in Table 1 below.

[0057] Table 1 - Performance Test Data of Samples

[0058] Data Analysis: Comparative analysis of the data in Table 1 shows that in the electronic-grade isopropanol prepared by this invention, the concentration of Na reaches 0.9-1.2 ppt, with a removal rate of 99.23-99.53%; the concentration of K reaches 1.0-1.2 ppt, with a removal rate of 99.58-99.67%; the concentration of Ca reaches 1.8-1.9 ppt, with a removal rate of 98.74-98.88%; and the concentration of Mg reaches 1.2-0.4 ppt, with a removal rate of [missing information]. The removal rates were as follows: Fe concentration reached 1.1-1.3 ppt, removal rate reached 99.67-99.71%; Cu concentration reached 0.5-0.7 ppt, removal rate reached 99.72-99.81%; Ni concentration reached 0.2-0.4 ppt, removal rate reached 99.91-99.96%; Cr concentration reached 0.2-0.4 ppt, removal rate reached 99.78-99.86%. Comparative Example 1 omitted step 3, lacking the pore-filled network containing fluorosulfonic acid, phosphonic acid, polyether and epoxy crosslinking. Although a cationic affinity layer could still be formed on the membrane surface, the membrane lacked a continuous cationic conductive phase, resulting in decreased transmembrane migration ability and high metal residue. Comparative Example 2 omits step 4, retains the pore-filled conductive network, but lacks a one-sided cation affinity layer, indicating that it still has a certain cation migration ability, but its ability to capture trace metals on the isopropanol side at the interface is reduced. In Comparative Example 3, step two was omitted, i.e., the pretreated isopropanol was not activated by trace amounts of water and carbon dioxide. As a result, the degree of ionization of metal contaminants in the low-polarity isopropanol system decreased. Therefore, even with the use of a complete asymmetric cation-conducting membrane, the electric field migration response was still weaker than that of the Example. All performance test data are superior to those of the comparative example, indicating that the present invention constructs an asymmetric cation conduction membrane with a single-sided cation affinity layer and an internal pore conduction network, and activates isopropanol with trace amounts of water and carbon dioxide, so that metal impurities migrate directionally to the ultrapure water side under the action of an electric field, thereby achieving efficient removal of metal ions such as Na, K, Ca, Mg, Fe, Cu, Ni, and Cr, reducing the metal content in electronic-grade isopropanol, and improving the purification efficiency of electronic-grade isopropanol.

[0059] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An electronic-grade isopropanol purification process for semiconductor wet cleaning, characterized in that, Includes the following steps: S1. The raw material isopropanol is pre-distilled to obtain pre-treated isopropanol by taking the middle fraction. S2. Introduce ultrapure water and electronic-grade carbon dioxide into the pretreated isopropanol to convert the metal impurities in the pretreated isopropanol into hydrated ions or migratable cations to obtain activated isopropanol. S3. Activated isopropanol is introduced into an isolated electroporation module equipped with an asymmetric cation conduction membrane. The asymmetric cation conduction membrane includes a porous support layer, a cation conduction filling phase formed in the pores of the porous support layer, and a cation affinity layer disposed on one side of the asymmetric cation conduction membrane. The activated isopropanol flows through the side close to the cation affinity layer, and ultrapure water flows through the other side of the asymmetric cation conduction membrane. Under the action of an applied pulsed DC electric field, the metal cations in the activated isopropanol are captured by the cation affinity layer, conducted by the cation conduction filling phase, and migrate to the ultrapure water side to obtain purified isopropanol. S4. The purified isopropanol is subjected to activation medium stripping, moisture restoration and particulate metal blocking treatment to obtain electronic grade isopropanol for semiconductor wet cleaning.

2. The electronic-grade isopropanol purification process for semiconductor wet cleaning according to claim 1, characterized in that, In step S1, the preparation method of pretreated isopropanol is as follows: the raw isopropanol is filtered through a filter medium with a pore size of 0.05-0.20 μm and then fed into a distillation column with 30-40 trays under nitrogen protection. It is stabilized under total reflux for 20-30 min. Then, the fore fraction, which accounts for 3-5 vol% of the volume of the raw isopropanol, is removed at a reflux ratio of 10-16:

1. Then, the middle fraction, which accounts for 85-90 vol% of the volume of the raw isopropanol, is collected at a reflux ratio of 5-7:

1. The middle fraction is cooled under nitrogen protection to obtain pretreated isopropanol.

3. The electronic-grade isopropanol purification process for semiconductor wet cleaning according to claim 1, characterized in that, In step S2, the preparation method of activated isopropanol is as follows: pretreated isopropanol is fed into a static mixer, electronic-grade ultrapure water is added to the static mixer to adjust the water content in the isopropanol to 400-600 ppm, and then electronic-grade carbon dioxide is dissolved at 25-28℃ and 0.4-0.5 MPa to make the dissolved carbon dioxide content in the isopropanol 1000-1300 ppm. The mixed isopropanol is then placed in a residence tube and left to stand for 12 min to obtain activated isopropanol.

4. The electronic-grade isopropanol purification process for semiconductor wet cleaning according to claim 1, characterized in that, In step S3, the isolated electroporation module is divided into an isopropanol channel and an ultrapure water channel by an asymmetric cation conduction membrane; The isopropanol channel is located on the side of the asymmetric cation-conducting membrane near the cation affinity layer. The effective width of the isopropanol channel is 180-200 mm, and the flow rate of isopropanol in the isopropanol channel is 1.1-1.4 L / min. The ultrapure water flow channel is located on the side of the asymmetric cation conduction membrane away from the cation affinity layer. The effective width of the ultrapure water flow channel is 180-200 mm, and the flow rate of ultrapure water in the ultrapure water flow channel is 0.7-0.8 L / min. The applied pulsed DC electric field strength is 16-20V / cm, with a cycle of 8-10s for power-on and 1-2s for power-off, and continuous processing for 30-40min.

5. The electronic-grade isopropanol purification process for semiconductor wet cleaning according to claim 1, characterized in that, In step S4, the preparation method of electronic grade isopropanol is as follows: purified isopropanol is passed into a degassing membrane contactor at a flow rate of 6-8 L / min for circulating degassing treatment until there are no visible microbubbles in the isopropanol, dissolved oxygen is below 0.5 mg / L, and dissolved carbon dioxide is below 20 ppm. The degassed isopropanol and molecular sieve are mixed at a liquid-solid ratio of 10:1, dried and dehydrated until the moisture content is below 45 ppm, and then filtered using a PTFE terminal filter with a pore size of 0.02-0.05 μm to obtain the finished electronic grade isopropanol.

6. The electronic-grade isopropanol purification process for semiconductor wet cleaning according to claim 1, characterized in that, The asymmetric cation-conducting membrane is obtained by the following steps: A1. Select ePTFE porous membrane as porous support layer. Clean the ePTFE porous membrane sequentially with electronic grade isopropanol, 60℃ ultrapure water and 0.01mol / L electronic grade nitric acid solution. Then rinse with ultrapure water until the conductivity of the cleaning solution is less than 1μS / cm. Finally, replace the water with electronic grade isopropanol and blow dry with high-purity nitrogen to obtain pretreated porous membrane. A2. Placing the pretreated porous membrane in an Ar / O2 mixed atmosphere for plasma activation treatment, resulting in an ion-activated porous membrane; A3. The ion-activated porous membrane is placed in a solution containing fluorosulfonic acid ionomer for vacuum impregnation, drying and heat treatment, so that the fluorosulfonic acid ionomer solution forms a cationic conductive filling phase in the pores of the ion-activated porous membrane, thus obtaining a filled porous membrane. A4. One side of the filled porous membrane is shielded, and the other side is coated with grafting solution. Then, it is placed in a drying oven at a temperature of 60-70℃ and dried to constant weight. The shielding is removed, and a cation affinity layer is formed on one side of the filled porous membrane to obtain an asymmetric cation conduction membrane.

7. The electronic-grade isopropanol purification process for semiconductor wet cleaning according to claim 6, characterized in that, In step A2, during the plasma activation treatment, the Ar flow rate is 60-80 sccm, the O2 flow rate is 18-22 sccm, the treatment power is 120W, and the treatment time in the plasma is 90-110s; in step A4, the coating amount of the grafting solution is 5-7 g / m².

8. The electronic-grade isopropanol purification process for semiconductor wet cleaning according to claim 6, characterized in that, In step A3, the preparation method of the fluorosulfonic acid ionomer solution is as follows: 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate sodium, 2-hydroxyethanephosphonic acid, polyethylene glycol-400, ethylene glycol diglycidyl ether, isopropanol, and ultrapure water are mixed evenly in a ratio of 2-3g:0.5-0.7g:1.6-2.2g:1-1.4g:18-20mL:75-80mL to obtain the fluorosulfonic acid ionomer solution. The vacuum impregnation, drying, and heat treatment include: placing the ion-activated porous membrane in the fluorosulfonic acid ionomer solution, vacuum impregnating the reaction system for 5-7 minutes after applying negative pressure, then restoring to normal pressure, allowing it to stand for 10-15 minutes, removing the membrane material, drying it at 65-75℃ for 30-40 minutes, and then heat-treating it at 150-160℃ for 25-35 minutes. The above operation is repeated 3 times to obtain a filled porous membrane.

9. The electronic-grade isopropanol purification process for semiconductor wet cleaning according to claim 6, characterized in that, In step A4, the grafting solution is prepared as follows: aminomethylphosphonic acid, disodium iminodiacetic acid, 2-hydroxymethyl-15-crown-5, purified water and ethanol are mixed and stirred until the system is dissolved. 3-glycidyl etheroxypropyltrimethoxysilane is added to the reaction system. The reaction system is heated to 50-60℃ and kept at this temperature for 30-50 min. The system is then allowed to cool naturally to room temperature to obtain the grafting solution.

10. The electronic-grade isopropanol purification process for semiconductor wet cleaning according to claim 9, characterized in that, The molar ratio of aminomethylphosphonic acid, disodium iminodiacetate, 2-hydroxymethyl-15-crown-5,3-glycidyl etheroxypropyltrimethoxysilane is 0.5:1.5:0.3:2.5, and the volume ratio of disodium iminodiacetate, purified water and ethanol is 1g:7mL:2mL.

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