Non-ionic Trimeric surfactant for efficient wafer cleaning

Abstract

The invention discloses a preparation method of a nonionic Trimeric surfactant for efficient wafer cleaning, and the specific preparation method comprises the following steps: S1, mixing polyethylene glycol monomethyl ether and BOC-tertiary leucine, adding dichloromethane as a reaction solvent, adding a catalyst and an activator, reacting at room temperature for 20-30 hours, and collecting a crude product BOC-tertiary leucine ester; s2, extracting the crude product BOC-tertiary leucine ester obtained in the step S1 with deionized water, performing rotary evaporation drying, and performing column chromatography purification to obtain purified BOC-tertiary leucine ester; s3, mixing the BOC-tert-leucine ester purified in the step S2 with dichloromethane, dropwise adding trifluoroacetic acid at 0 DEG C, gradually heating to room temperature, and stirring to react for 2-4 hours to obtain a crude product tert-leucine ester; s4, adjusting the pH value of the crude product tert-leucine ester to 8-9 by using a NaOH aqueous solution with the concentration of 1 mol / L, extracting, and carrying out rotary evaporation drying to obtain tert-leucine ester; and S5, adding the tertiary leucine ester in the step S4 and trimesic aldehyde into an ethanol solution, mixing, carrying out reflux reaction for 10-15 hours at 78-80 DEG C, and carrying out rotary evaporation drying and column chromatography purification to obtain the nonionic Trimeric surfactant.

Description

Technical Field

[0001] This invention relates to the field of surfactants, and more particularly to a nonionic trimeric surfactant for efficient wafer cleaning. Background Technology

[0002] In semiconductor manufacturing, chemical mechanical polishing (CMP) is a key process for achieving global wafer planarization. Cerium oxide nanoparticles are widely used in processes such as shallow trench isolation due to their high polishing rate, but this process also introduces a large number of these polishing particles as residue. Under the high pressure and high temperature environment of polishing, these particles may adhere to the wafer surface through van der Waals forces or even covalent bonds with surface silanol groups, forming stubborn contaminants. Incomplete cleaning will directly lead to fatal defects such as short circuits and leakage, severely restricting the yield and reliability of advanced process chips. Therefore, post-CMP cleaning is a core step in ensuring device performance. Advanced wet cleaning typically uses diluted chemical solutions (such as dilute hydrofluoric acid or SC1 standard cleaning solution) combined with physical aids such as spraying and megasonic waves. As technology nodes continue to shrink and chip patterns become increasingly complex, extreme requirements are placed on the wettability of the cleaning solution: the solution must have extremely low surface tension to quickly penetrate and completely wet nanoscale slits and trenches.

[0003] Surfactants are key additives for improving the wettability of cleaning solutions. However, traditional ionic surfactants may interfere with the charge state of the wafer surface due to electrostatic interactions, and the risk of introducing metal ions makes them unsuitable for the ultra-high purity requirements of semiconductor processes. Nonionic surfactants have attracted attention due to their low susceptibility to metal ion introduction and good acid and alkali resistance. However, existing surfactants still face challenges in targeting nano-pollutants with extremely strong adsorption capacity, such as cerium oxide. Their molecular structure limits the adsorption strength and steric hindrance at the solid-liquid interface, making it difficult to effectively insert between nanoparticles and the wafer surface and stably peel off and disperse them. Especially in diluted cleaning solution environments, their interfacial activity and stability are often insufficient, making it difficult to meet the requirements of efficient cleaning.

[0004] Therefore, there is an urgent need in this field for a new type of surfactant that can not only meet the stringent requirements of semiconductor processes for ultrapurity and ultra-low surface tension, but also provide excellent interfacial adsorption capacity, strong steric hindrance effect and excellent chemical stability for the cleaning mechanism of nanoparticle contamination. Summary of the Invention

[0005] The purpose of this invention is to provide a nonionic trimeric surfactant for efficient wafer cleaning, in order to solve the problem of insufficient interfacial activity and stability mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A nonionic trimeric surfactant for high-efficiency wafer cleaning, wherein the structural formula of the nonionic trimeric surfactant is as follows: Where n is a natural number.

[0007] Preferably, n is 4 to 16.

[0008] Preferably, n is 4, 7, 11, or 16.

[0009] A method for preparing a nonionic trimeric surfactant for efficient wafer cleaning, the specific preparation method including the following steps: S1. Mix polyethylene glycol monomethyl ether and BOC-tert-leucine, add dichloromethane as a reaction solvent, then add a catalyst and activator and react at room temperature for 20-30 h to collect the crude product BOC-tert-leucine ester. S2. The crude product BOC-tert-leucine ester described in step S1 is extracted with deionized water, dried by rotary evaporation, and then purified by column chromatography to obtain purified BOC-tert-leucine ester. S3. The purified BOC-tert-leucine ester described in step S2 is mixed with dichloromethane, and trifluoroacetic acid is added dropwise at 0 °C. The mixture is then gradually raised to room temperature and stirred for 2-4 h to obtain the crude product tert-leucine ester. S4. The pH of the crude product tert-leucine ester was adjusted to 8-9 using a 1 mol / L NaOH aqueous solution. After extraction, the product was dried by rotary evaporation to obtain tert-leucine ester. S5. The tert-leucine ester described in step S4 and pyromellitic trimethylaldehyde are added to an ethanol solution and mixed. The mixture is refluxed at 78-80°C for 10-15 hours. The nonionic Trimeric surfactant is obtained by rotary drying and column chromatography purification.

[0010] Preferably, in step S1, the catalyst is 1-ethyl-(3-dimethylaminopropyl)carbodiimide and the activator is 4-dimethylaminopyridine.

[0011] Preferably, the molar ratio of BOC-tert-leucine, polyethylene glycol monomethyl ether, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 4-dimethylaminopyridine and dichloromethane is 1:1.2:1.2:0.01:10~20, and the molecular weight of polyethylene glycol monomethyl ether is 200-750.

[0012] Preferably, in step S3, the volume ratio of dichloromethane to trifluoroacetic acid is 2:1.

[0013] Preferably, in step S5, the molar ratio of the tert-leucine ester to pyromellitic trimethylaldehyde is 3:1.

[0014] The beneficial effects of this invention are: 1. This invention develops a novel class of nonionic trimeric surfactants. The molecule covalently links three hydrophilic head groups to three hydrophobic tail chains via a benzene ring linker, forming a unique trimer structure. This structure achieves a more compact and stable molecular arrangement at the interface even at extremely low concentrations. Its multiple hydrophobic chains synergistically enhance adsorption strength on hydrophobic or partially hydrophilic surfaces, while the three hydrophilic segments construct a denser hydration layer, generating a strong steric hindrance effect. This allows for the efficient stripping, dispersion, and suspension of cerium oxide nanoparticles, providing a novel solution to the challenges of cleaning nanoparticles in advanced processes.

[0015] 2. The product of this invention is a nonionic trimeric surfactant for high-efficiency wafer cleaning. As a surfactant additive for wet electronic chemicals in the semiconductor and new display fields, its addition can effectively reduce the contact angle of wet electronic chemicals and enhance their wettability and cleaning effect. 3. The nonionic trimeric surfactant for efficient wafer cleaning of this invention does not ionize in solution and will not introduce additional impurity ions; 4. The special structure of the nonionic Trimeric surfactant for high-efficiency wafer cleaning in this invention makes it easy to be adsorbed on gas / liquid surfaces, with good wettability enhancement, and has excellent properties such as resistance to strong alkali and strong acid environments. It can be used in conjunction with a variety of wet electronic chemicals such as cleaning solutions in the semiconductor and new display fields. 5. The nonionic trimeric surfactant for high-efficiency wafer cleaning of the present invention is fluorine-free, non-toxic, biodegradable, and environmentally friendly; 6. The present invention provides a simple and practical method for preparing a nonionic trimeric surfactant for efficient wafer cleaning. Attached Figure Description

[0016] Figure 1 This is the infrared spectrum of a nonionic trimeric surfactant (n=4) for high-efficiency wafer cleaning in Example 1; Figure 2 Example 1 describes a nonionic trimeric surfactant (n=4) for high-efficiency wafer cleaning. 1 HNMR spectrum; Figure 3 The contact angle diagrams are shown before and after adding a high-efficiency nonionic trimeric surfactant (n=4) to the cleaning solution; Figure 4The images show the cleaning effect of cerium oxide nanoparticles before and after adding a high-efficiency nonionic trimeric surfactant (n=4) to the cleaning solution. Figure 5 This is the infrared spectrum of a nonionic trimeric surfactant (n=7) for high-efficiency wafer cleaning, as described in Example 2. Figure 6 Example 2 describes a nonionic trimeric surfactant (n=7) for high-efficiency wafer cleaning. 1 HNMR spectrum; Figure 7 The contact angle diagrams are before and after adding a high-efficiency nonionic trimeric surfactant (n=7) to the cleaning solution; Figure 8 The images show the cleaning effect of cerium oxide nanoparticles before and after adding a high-efficiency nonionic trimeric surfactant (n=7) to the cleaning solution. Figure 9 This is the infrared spectrum of a nonionic trimeric surfactant (n=11) for high-efficiency wafer cleaning, as described in Example 3. Figure 10 Example 3 describes a nonionic trimeric surfactant (n=11) for high-efficiency wafer cleaning. 1 HNMR spectrum; Figure 11 This is a contact angle diagram before and after adding a high-efficiency nonionic trimeric surfactant (n=11) to the cleaning solution; Figure 12 The images show the cleaning effect of cerium oxide nanoparticles before and after adding a high-efficiency nonionic trimeric surfactant (n=11) to the cleaning solution. Figure 13 This is the infrared spectrum of a nonionic trimeric surfactant (n=16) for high-efficiency wafer cleaning, as described in Example 4. Figure 14 Example 4 describes a nonionic trimeric surfactant (n=16) for high-efficiency wafer cleaning. 1 HNMR spectrum; Figure 15 This is a contact angle diagram before and after adding a high-efficiency nonionic trimeric surfactant (n=16) to the cleaning solution; Figure 16 The images show the cleaning effect of cerium oxide nanoparticles before and after adding a high-efficiency nonionic trimeric surfactant (n=16) to the cleaning solution. Figure 17The images show the cleaning effect of silica nanoparticles before and after adding a high-efficiency nonionic trimeric surfactant (n=16) to the cleaning solution. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0018] This invention provides a nonionic trimeric surfactant for high-efficiency wafer cleaning, specifically including the following steps: S1. Place polyethylene glycol monomethyl ether and BOC-tert-leucine into a reaction vessel, add dichloromethane as a reaction solvent to dissolve them completely, add a catalyst and activator, react at room temperature for 20-30 h, and then collect the crude product BOC-tert-leucine ester. S2. The crude product was extracted with deionized water, dried by rotary evaporation, and purified by column chromatography to obtain BOC-tert-leucine ester. S3. BOC-tert-leucine ester and dichloromethane were placed in a reaction vessel. Trifluoroacetic acid was added dropwise at 0 °C and then gradually raised to room temperature. The mixture was stirred for 2-4 h to obtain the crude product, tert-leucine ester. S4. The pH of the crude product tert-leucine ester was adjusted to 8-9 using a 1 mol / L NaOH aqueous solution. After extraction, the product was dried by rotary evaporation to obtain tert-leucine ester. S5. Add tert-leucine ester and trimesin to an ethanol solution and react. Reflux at 78-80 °C for 10-15 hours. Obtain the nonionic Trimeric surfactant by rotary evaporation and column chromatography purification.

[0019] The structural formula of the nonionic trimeric surfactant is as follows: Where n is a natural number; In one feasible implementation, n is 4, 7, 11, or 16.

[0020] Example 1: The preparation method of this invention is shown in the following formula: ; The reactants are BOC-tert-leucine, polyethylene glycol monomethyl ether, pyromellitic methyl ether, and trifluoroacetic acid; TFA is trifluoroacetic acid, DCM is dichloromethane, EDC is 1-ethyl-(3-dimethylaminopropyl)carbodiimide, DMAP is 4-dimethylaminopyridine, mPEG is polyethylene glycol monomethyl ether, and EtOH is ethanol.

[0021] 1. Take BOC-tert-leucine (11.5 g, 0.05 mol), polyethylene glycol monomethyl ether (12 g, 0.06 mol) with a molecular weight of 200, 1-ethyl-(3-dimethylaminopropyl)carbodiimide (9.3 g, 0.06 mol) and 4-dimethylaminopyridine (0.06 g) and place them in a reaction vessel, put in a rotor and add 42.5 g of dichloromethane as a solvent and stir thoroughly. 2. React at room temperature for 20-30 hours, collect the crude product and extract it with deionized water, then dry the organic phase by rotary evaporation, and obtain the pale yellow intermediate product BOC-tert-leucine ester by column chromatography; 3. Dissolve 4.21 g (0.01 mol) of BOC-tert-leucine ester in 20 mL of dichloromethane, and add 10 mL of trifluoroacetic acid dropwise at 0 °C while stirring thoroughly. 4. After reacting at room temperature for 2-4 hours, the crude product was collected. The pH of the system was adjusted to 8-9 using an aqueous solution of NaOH (1 mol / L). After extraction, the organic phase was dried by rotary evaporation to obtain the yellow intermediate product tert-leucine ester. 5. Tertiary leucine ester (1.9 g, 0.06 mol) and trimesin (0.32 g, 0.02 mol) were refluxed in ethanol solution and stirred thoroughly for 10-15 hours. 6. After the reaction is complete, the solvent is removed by rotary evaporation and the final product is obtained by column chromatography.

[0022] like Figure 1 As shown, the infrared spectrum of this embodiment is as follows: 2960-2874 cm -1 Peak 1 is the absorption peak of the stretching vibration of methyl groups; 1732 cm⁻¹ -1 Peak 2 is the absorption peak of the stretching vibration of the ester group (C=O); 1635 cm⁻¹ -1 Peak 3 is the stretching vibration peak of the imine bond (C=N); 1108 cm⁻¹ -1 (peak4) The COC on the polyethylene oxide chain is the absorption peak of stretching vibration.

[0023] like Figure 2 As shown in this embodiment 1 HNMR spectrum: 1H NMR (500 MHz, Chloroform-d) δ 8.44 – 7.30 (m, 6H), 4.36 – 4.16 (m,6H), 3.67 – 3.53 (m, 54H), 3.38 (d, J = 4.3 Hz, 9H), 1.06 – 1.01 (m, 27H). like Figure 3 As shown in the figure, the contact angle diagrams before and after this embodiment are shown. It can be seen from the comparison of the figures that after adding nonionic Trimeric surfactant to the cleaning solution, the interface contact angle becomes smaller, indicating that the wettability of the cleaning solution is enhanced.

[0024] like Figure 4 As shown in the figure, the cleaning effect of cerium oxide nanoparticles before and after this embodiment is shown. It can be seen from the comparison of the figures that after adding nonionic Trimeric surfactant to the cleaning solution, the number of cerium oxide nanoparticles on the wafer surface is reduced, indicating that it has a better cleaning effect.

[0025] Example 2: 1. Take BOC-tert-leucine (11.5 g, 0.05 mol), polyethylene glycol monomethyl ether (21 g, 0.06 mol) with a molecular weight of 350, 1-ethyl-(3-dimethylaminopropyl)carbodiimide (9.3 g, 0.06 mol) and 4-dimethylaminopyridine (0.06 g) and put them into a reaction vessel, put in a rotor and add 50 g of dichloromethane as a solvent and stir it thoroughly. 2. React at room temperature for 20-30 hours, collect the crude product and extract it with deionized water, then dry the organic phase by rotary evaporation, and obtain the pale yellow intermediate product BOC-tert-leucine ester by column chromatography; 3. Dissolve 5.5 g (0.01 mol) of BOC-tert-leucine ester in 20 mL of dichloromethane, and add 10 mL of trifluoroacetic acid dropwise at 0 °C while stirring thoroughly; 4. After reacting at room temperature for 2-4 hours, the crude product was collected. The pH of the system was adjusted to 8-9 using an aqueous solution of NaOH (1 mol / L). After extraction, the organic phase was dried by rotary evaporation to obtain the yellow intermediate product tert-leucine ester. 5. Tertiary leucine ester (2.7 g, 0.06 mol) and trimesin (0.32 g, 0.02 mol) were refluxed in ethanol solution and stirred thoroughly for 10-15 hours. 6. After the reaction is complete, the solvent is removed by rotary evaporation and the final product is obtained by column chromatography.

[0026] like Figure 5 As shown, the infrared spectrum of this embodiment is as follows: 2960-2874 cm-1 Peak 1 is the absorption peak of the stretching vibration of methyl groups; 1732 cm⁻¹ -1 Peak 2 is the absorption peak of the stretching vibration of the ester group (C=O); 1635 cm⁻¹ -1 Peak 3 is the stretching vibration peak of the imine bond (C=N); 1108 cm⁻¹ -1 (peak4) The COC on the polyethylene oxide chain is the absorption peak of stretching vibration.

[0027] like Figure 6 As shown in this embodiment 1 HNMR spectrum: 1 HNMR (500 MHz, Chloroform-d) δ 8.57 – 8.06 (m, 6H), 4.35 (dddd, J =45.7, 22.5, 10.6, 6.4 Hz, 6H), 3.86 – 3.52 (m, 81H), 3.40 (s, 9H), 1.10 –1.06 (m, 27H). like Figure 7 As shown in the figure, the contact angle diagrams before and after this embodiment are shown. It can be seen from the comparison of the figures that after adding nonionic Trimeric surfactant to the cleaning solution, the interface contact angle becomes smaller, indicating that the wettability of the cleaning solution is enhanced.

[0028] like Figure 8 As shown in the figure, the cleaning effect of cerium oxide nanoparticles before and after this embodiment is shown. It can be seen from the comparison of the figures that after adding nonionic Trimeric surfactant to the cleaning solution, the number of cerium oxide nanoparticles on the wafer surface is reduced, indicating that it has a better cleaning effect.

[0029] Example 3: 1. Take BOC-tert-leucine (11.5 g, 0.05 mol), polyethylene glycol monomethyl ether (30 g, 0.06 mol) with a molecular weight of 500, 1-ethyl-(3-dimethylaminopropyl)carbodiimide (9.3 g, 0.06 mol) and 4-dimethylaminopyridine (0.06 g) and put them into a reaction vessel, put in a rotor and add 50 g of dichloromethane as a solvent and stir it thoroughly. 2. React at room temperature for 20-30 hours, collect the crude product and extract it with deionized water, then dry the organic phase by rotary evaporation, and obtain the pale yellow intermediate product BOC-tert-leucine ester by column chromatography; 3. Dissolve BOC-tert-leucine ester (7.3 g, 0.01 mol) in 20 mL of dichloromethane, and add 10 mL of trifluoroacetic acid dropwise at 0 °C while stirring thoroughly; 4. After reacting at room temperature for 2-4 hours, the crude product was collected. The pH of the system was adjusted to 8-9 using an aqueous solution of NaOH (1 mol / L). After extraction, the organic phase was dried by rotary evaporation to obtain the yellow intermediate product tert-leucine ester. 5. Tertiary leucine ester (3.8 g, 0.06 mol) and trimesin (0.32 g, 0.02 mol) were refluxed in ethanol solution and stirred thoroughly for 10-15 hours. 6. After the reaction is complete, the solvent is removed by rotary evaporation and the final product is obtained by column chromatography.

[0030] like Figure 9 As shown, the infrared spectrum of this embodiment is as follows: 2960-2874 cm -1 Peak 1 is the absorption peak of the stretching vibration of methyl groups; 1732 cm⁻¹ -1 Peak 2 is the absorption peak of the stretching vibration of the ester group (C=O); 1635 cm⁻¹ -1 Peak 3 is the stretching vibration peak of the imine bond (C=N); 1108 cm⁻¹ -1 (peak4) The COC on the polyethylene oxide chain is the absorption peak of stretching vibration.

[0031] like Figure 10 As shown in this embodiment 1 HNMR spectrum: 1 HNMR (400 MHz, Chloroform-d) δ8.39–7.54 (m, 6H), 4.39 – 4.23 (m, 6H), 3.78– 3.43 (m, 128H), 3.38 (s, 9H), 1.05 (q, J = 3.5, 2.9 Hz, 27H). like Figure 11 As shown in the figure, the contact angle diagrams before and after this embodiment are shown. It can be seen from the comparison of the figures that after adding nonionic Trimeric surfactant to the cleaning solution, the interface contact angle becomes smaller, indicating that the wettability of the cleaning solution is enhanced.

[0032] like Figure 12 As shown in the figure, the cleaning effect of cerium oxide nanoparticles before and after this embodiment is shown. It can be seen from the comparison of the figures that after adding nonionic Trimeric surfactant to the cleaning solution, the number of cerium oxide nanoparticles on the wafer surface is reduced, indicating that it has a better cleaning effect.

[0033] Example 4: 1. Take BOC-tert-leucine (11.5 g, 0.05 mol), polyethylene glycol monomethyl ether (45 g, 0.06 mol) with a molecular weight of 750, 1-ethyl-(3-dimethylaminopropyl)carbodiimide (9.3 g, 0.06 mol) and 4-dimethylaminopyridine (0.06 g) and put them into a reaction vessel, put in a rotor and add 85 g of dichloromethane as a solvent and stir it thoroughly. 2. React at room temperature for 20-30 hours, collect the crude product and extract it with deionized water, then dry the organic phase by rotary evaporation, and obtain the pale yellow intermediate product BOC-tert-leucine ester by column chromatography; 3. Dissolve BOC-tert-leucine ester (9.5 g, 0.01 mol) in 20 mL of dichloromethane, and add 10 mL of trifluoroacetic acid dropwise at 0 °C while stirring thoroughly; 4. After reacting at room temperature for 2-4 hours, the crude product was collected. The pH of the system was adjusted to 8-9 using an aqueous solution of NaOH (1 mol / L). After extraction, the organic phase was dried by rotary evaporation to obtain the yellow intermediate product tert-leucine ester. 5. Tertiary leucine ester (5.1 g, 0.06 mol) and trimesin (0.32 g, 0.02 mol) were refluxed in ethanol solution and stirred thoroughly for 10-15 hours; 6. After the reaction is complete, the solvent is removed by rotary evaporation and the final product is obtained by column chromatography.

[0034] like Figure 13 As shown, the infrared spectrum of this embodiment is as follows: 2960-2874 cm -1 Peak 1 is the absorption peak of the stretching vibration of methyl groups; 1732 cm⁻¹ -1 Peak 2 is the absorption peak of the stretching vibration of the ester group (C=O); 1635 cm⁻¹ -1 Peak 3 is the stretching vibration peak of the imine bond (C=N); 1108 cm⁻¹ -1 (peak4) The COC on the polyethylene oxide chain is the absorption peak of stretching vibration.

[0035] like Figure 14 As shown in this embodiment 1 HNMR spectrum: 1 HNMR (500 MHz, Chloroform-d) δ 8.34 – 7.81 (m, 6H), 4.40 – 4.20 (m,6H), 3.77 – 3.52 (m, 189H), 3.38 (s, 9H), 1.05 (d, J = 3.8 Hz, 27H). like Figure 15 As shown in the figure, the contact angle diagrams before and after this embodiment are shown. It can be seen from the comparison of the figures that after adding nonionic Trimeric surfactant to the cleaning solution, the interface contact angle becomes smaller, indicating that the wettability of the cleaning solution is enhanced.

[0036] like Figure 16 As shown in the figure, the cleaning effect of cerium oxide nanoparticles before and after this embodiment is as follows; it can be seen from the comparison of the figures that after adding nonionic Trimeric surfactant to the cleaning solution, there are no cerium oxide nanoparticle contaminants on the wafer surface, and the stains are removed.

[0037] like Figure 17 The image shows the before and after cleaning effect of silica nanoparticles in this embodiment. As can be seen from the comparison in the image, after adding nonionic Trimeric surfactant to the cleaning solution, there are no silica nanoparticle contaminants on the wafer surface, thus achieving the removal of stains.

[0038] The nonionic trimeric surfactants prepared in Examples 1-4 were applied to cleaning solutions at a concentration of 0.001 mol / L. The contact angle and surface tension of the cleaning solution before and after cleaning were tested, and the data are shown in Table 1 below: Table 1 The data in the table show that the contact angle and surface tension of the cleaning solution decreased significantly after the addition of the nonionic Trimeric surfactant for this high-efficiency wafer cleaning.

[0039] Table 2 shows the evaluation of cleaning results before and after adding a nonionic trimeric surfactant (concentration of 0.001 mol / L) for high-efficiency wafer cleaning to wet electronic chemicals for semiconductor displays (taking cleaning solution as an example); Table 2 Evaluation criteria for cleaning results: A indicates no nanoparticle contaminants, B indicates the presence of few nanoparticle contaminants, and C indicates the presence of many nanoparticle contaminants. As can be seen from the data in the table, the cleaning results are significantly improved after the addition of the nonionic Trimeric surfactant to the cleaning solution for this high-efficiency wafer cleaning. When n is 16, cerium oxide and silicon dioxide nanoparticle contaminants on the wafer surface are completely removed.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A nonionic trimeric surfactant for high-efficiency wafer cleaning, characterized in that: The structural formula of the nonionic trimeric surfactant is as follows: Where n is a natural number.

2. The nonionic trimeric surfactant for high-efficiency wafer cleaning according to claim 1, characterized in that: n is 4~16.

3. The nonionic trimeric surfactant for high-efficiency wafer cleaning according to claim 1, characterized in that: n is 4, 7, 11, or 16.

4. A method for preparing a nonionic trimeric surfactant for high-efficiency wafer cleaning, characterized in that, The specific preparation method includes the following steps: S1. Mix polyethylene glycol monomethyl ether and BOC-tert-leucine, add dichloromethane as a reaction solvent, then add a catalyst and activator and react at room temperature for 20-30 h to collect the crude product BOC-tert-leucine ester. S2. The crude product BOC-tert-leucine ester described in step S1 is extracted with deionized water, dried by rotary evaporation, and then purified by column chromatography to obtain purified BOC-tert-leucine ester. S3. The purified BOC-tert-leucine ester described in step S2 is mixed with dichloromethane, and trifluoroacetic acid is added dropwise at 0 °C. The mixture is then gradually raised to room temperature and stirred for 2-4 h to obtain the crude product tert-leucine ester. S4. The pH of the crude product tert-leucine ester was adjusted to 8-9 using a 1 mol / L NaOH aqueous solution. After extraction, the product was dried by rotary evaporation to obtain tert-leucine ester. S5. The tert-leucine ester described in step S4 and pyromellitic trimethylaldehyde are added to an ethanol solution and mixed. The mixture is refluxed at 78-80 °C for 10-15 hours. The nonionic Trimeric surfactant is obtained by rotary drying and column chromatography purification.

5. The method for preparing a nonionic trimeric surfactant for high-efficiency wafer cleaning according to claim 4, characterized in that: In step S1, the catalyst is 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and the activator is 4-dimethylaminopyridine.

6. The method for preparing a nonionic trimeric surfactant for high-efficiency wafer cleaning according to claim 5, characterized in that: The molar ratio of BOC-tert-leucine, polyethylene glycol monomethyl ether, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 4-dimethylaminopyridine and dichloromethane is 1:1.2:1.2:0.01:10~20, and the molecular weight of polyethylene glycol monomethyl ether is 200-750.

7. The method for preparing a nonionic trimeric surfactant for high-efficiency wafer cleaning according to claim 4, characterized in that: In step S3, the volume ratio of dichloromethane to trifluoroacetic acid is 2:

1.

8. The method for preparing a nonionic trimeric surfactant for high-efficiency wafer cleaning according to claim 4, characterized in that: In step S5, the molar ratio of the tert-leucine ester to pyromellitic trimethylaldehyde is 3:1.

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