Preparation method and use method of original silicon wafer alkali polishing additive

Abstract

The invention discloses a preparation method and a use method of an original silicon wafer alkali polishing additive, and belongs to the technical field of preparation of alkali polishing additives. The preparation method of the original silicon wafer alkali polishing additive comprises the following steps: step 1, mixing the defoaming agent, the active substance, the surface brightener, the pH regulator, the preservative, the coloring agent, the antifouling bactericide and the deionized water, and fully stirring until no solid particles exist to obtain a mixture; and 2, standing the mixture until the foam completely disappears, and filtering to obtain the original silicon wafer alkali polishing additive. The alkali polishing additive prepared through the method is good in polishing effect, high in efficiency, good in stability and capable of effectively weakening line marks and improving the flatness of a polished surface.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of alkali polishing additives, and specifically relates to a preparation method and a use method of an alkali polishing additive for raw silicon wafers. Background Art

[0002] The double-sided alkaline polishing additive for raw silicon wafers is a chemical additive that helps polish both sides of raw silicon wafers during the production process of solar cells. During the processing of raw silicon wafers, the surface will be continuously contaminated and leave a mechanical damage layer. Alkaline polishing of raw silicon wafers can effectively remove surface dirt and mechanical damage layers, thereby helping the subsequent texturing process to obtain a uniform velvet surface.

[0003] At present, the following problems often exist in the alkali polishing process for raw silicon wafers: first, the alkali polishing is not thorough, resulting in poor surface flatness of the silicon wafer and large height difference of the tower base; second, the tower base line marks are very heavy after polishing; third, there is still dirt on the surface of the silicon wafer after polishing that cannot be removed; fourth, there is a phenomenon of silicon wafer floating during the polishing process. The above problems will affect the subsequent texturing steps. To improve the above problems, alkali polishing additives can be added during the alkali polishing process, but conventional additives have poor stability and poor flatness after polishing. The polishing effect needs to be further improved.

[0004] It can be seen that the development of a preparation method and a method for using an alkali polishing additive for raw silicon wafers that can weaken line marks, improve the flatness of the polished surface, have a good polishing effect, high efficiency, and good stability meets market needs, has great market value and application prospects, and is of great significance to promoting the development of the field of alkali polishing of raw silicon wafers. Summary of the invention

[0005] The object of the present invention is to provide a preparation method and a use method of an alkali polishing additive for raw silicon wafers, so as to solve the technical problems of heavy line marks, low polishing surface flatness and poor polishing effect in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing an alkali polishing additive for raw silicon wafers, comprising the following steps:

[0008] Step 1: Mix the defoamer, active substance, surface brightener, pH adjuster, preservative, colorant, antifouling bactericide and deionized water, and stir thoroughly until there are no solid particles to obtain a mixture;

[0009] Step 2: Let the mixture stand until the foam disappears completely, filter it, and obtain the original silicon wafer alkali polishing additive.

[0010] Preferably, in step 1, the dosage ratio of the defoaming agent, active substance, surface brightener, pH regulator, preservative, colorant, antifouling bactericide and deionized water is (0.5-4) g: (0.5-4) g: (0.5-2) g: (0.1-0.3) g: (0.05-0.1) g: (0.04-0.05) g: (0.12-2) g: (90.2-94.6) mL.

[0011] Preferably, the method for preparing the defoaming agent comprises the following steps:

[0012] Q1: Add N,N-diethyl-1,4-phenylenediamine and triethylamine to a container, then add diethyl ether, and slowly drop 2-methoxyethyl while stirring under ice-water bath conditions. Control the drop time. After the drop addition is complete, react at room temperature, then heat the reaction. After the reaction is complete, rotary evaporate, wash, and dry to obtain intermediate 1;

[0013] Q2: Add chloroacetic acid and sodium hydroxide to distilled water, stir and dissolve to obtain a mixed solution, then add intermediate 1 to acetone, stir and dissolve, then add to the mixed solution, heat to reflux, after reflux, rotary evaporate, dissolve, filter, and distill under reduced pressure to obtain a crude product, continue to dissolve the crude product, recrystallize, and filter to obtain a defoaming agent.

[0014] In the above process, the synthetic reaction formula of the defoamer is as follows:

[0015]

[0016] The results of mass spectrometry analysis of intermediate 1 were: m / z: 694.11 (100.0%), 695.11 (23.5%), 696.12 (2.5%); the results of mass spectrometry analysis of defoaming agent were: m / z: 752.12 (100.0%), 753.12 (25.2%), 754.12 (3.8%).

[0017] Preferably, in Q1, the amount ratio of N,N-diethyl-1,4-phenylenediamine, triethylamine, ether and 2-methoxyethyl is (5.2-5.8) g: (5-5.4) g: (50-75) mL: (18.8-20.2) g, the dropping time is controlled to be 1-2 h, the reaction is carried out at room temperature for 1-2 h, the heating reaction temperature is 40-50°C, the reaction time is 3-5 h, the reaction is washed with deionized water, the drying temperature is 50-70°C, and the time is 10-12 h.

[0018] Preferably, in Q2, the dosage ratio of chloroacetic acid, sodium hydroxide, distilled water, intermediate 1 and acetone is (3-4.5) g: (1.2-2.1) g: (10-15) mL: (16-18.8) g: (50-75) mL, the heating reflux temperature is 60-70°C, the time is 4-6h, and it is dissolved in anhydrous ethanol. The crude product is further dissolved in anhydrous ethanol and added to ether for recrystallization.

[0019] Preferably, the active substance consists of one or more of alkyl glucoside, sodium metabisulfite and sodium hypochlorite; the surface brightener consists of one or more of powdered sugar, pyridine-3-carboxylic acid, diatomaceous earth and sodium sulfate; the pH adjuster consists of one or more of hydrochloric acid, citric acid, sodium hydroxide and potassium hydroxide; the preservative consists of one or more of sodium benzoate, potassium sorbate and dehydroacetic acid; and the colorant consists of one or more of brown pigment, caramel pigment and cocoa pigment.

[0020] Preferably, the method for preparing the antifouling bactericide comprises the following steps:

[0021] S1: Phenylhydrazine, malonic acid and methanol are added to a container equipped with an electric stirrer and a spherical condenser, and then sodium is added to the methanol, stirred to dissolve and then added dropwise to the container. After the addition is complete, the temperature is raised to reflux for reaction. After the reaction is complete, the mixture is filtered, rotary evaporated, washed, filtered, and dried to obtain intermediate A;

[0022] S2: Add intermediate A, boron trifluoride etherate and acetyl chloride into a container, heat and stir, then add acetyl chloride to continue the reaction, cool after the reaction, pour into ice water, extract, combine the organic layers, extract, adjust the pH, rotary evaporate, wash, filter, add ethanol to the filtrate, then add 4-chlorophenylhydrazine, heat to dissolve, cool to react, filter, and obtain intermediate B;

[0023] S3: Add intermediate B to a container filled with dichloromethane, stir in an ice bath, add triethylamine and ethyl chloroformate to dichloromethane, stir to dissolve, and slowly add dropwise to the container. After the addition is completed, react, wash, dry, rotary evaporate, recrystallize, and filter to obtain an antifouling bactericidal agent.

[0024] In the above process, the synthetic reaction formula of the antifouling bactericide is as follows:

[0025]

[0026] The results of mass spectrometry analysis of intermediate A are: m / z: 176.06 (100.0%), 177.06 (10.6%); the results of mass spectrometry analysis of intermediate B are: m / z: 342.09 (100.0%), 344.09 (32.6%), 343.09 (20.1%), 345.09 (6.0%), 344.10 (1.6%); the results of mass spectrometry analysis of antifouling bactericide are: m / z: 414.11 (100.0%), 416.11 (33.1%), 415.11 (23.3%), 417.11 (7.1%), 416.12 (2.3%), 418.11 (1.1%).

[0027] Preferably, in S1, the dosage ratio of phenylhydrazine, malonic acid and sodium is (54-100) g: (55-90) g: (10-15) g, the temperature of the reflux reaction is 60-70° C., the reaction time is 8-10 h, and the reaction is washed with ice methanol; in S2, the dosage ratio of intermediate A, boron trifluoride etherate, acetyl chloride added for the first time, acetyl chloride added for the second time and 4-chlorophenylhydrazine is (2-4) g: (50-90) mL: (2.4-3. 2)g: (0.8-1.1)g: (1.2-1.8)g, heating and stirring temperature is 90-95℃, stirring time is 8-10h, continued reaction time is 2-3h, extracted with ethyl acetate, extracted with saturated sodium hydroxide solution, adjusted pH=2-3 with 2mol / L hydrochloric acid, washed with ethanol, heated and dissolved at 40-60℃, time is 1-3h, cooled and reacted at 30-35℃, time is 10-12h.

[0028] Preferably, in S3, the amount ratio of intermediate B, triethylamine and ethyl chloroformate is (0.5-1.2) g: (0.17-0.38) g: (0.17-0.39) g, the reaction temperature is 2-5°C, the reaction time is 4-6h, and the product is washed with 1 mol / L hydrochloric acid and 5 wt% sodium hydroxide solution, and recrystallized with a mixed solution of ether and petroleum ether in a volume ratio of 3:1.

[0029] Preferably, a method for using an alkali polishing additive for raw silicon wafers comprises the following steps:

[0030] Step (1): adding the prepared raw silicon wafer alkali polishing additive to a sodium hydroxide solution having a mass fraction of 1-6 wt%, wherein the amount ratio of the raw silicon wafer alkali polishing additive to the sodium hydroxide solution is (0.2-3) g: (100-105) mL, and after sufficient mixing, obtaining an alkali polishing solution;

[0031] Step (2): Add the original silicon wafer into an alkaline polishing solution and polish it at 60-80°C for 2-6 minutes to obtain a smooth and flat silicon wafer.

[0032] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0033] 1. The alkali polishing additive for raw silicon wafers prepared by the present invention can effectively weaken line marks, improve the surface flatness of silicon wafers, effectively remove dirt and mechanical damage layers on the surface of raw silicon wafers, and help the subsequent texturing process to obtain a more uniform velvet surface. The alkali polishing additive for raw silicon wafers obtained can be used once to continuously polish 3 batches of raw silicon wafers.

[0034] 2. The present invention adds the prepared defoaming agent to the original silicon wafer alkali polishing additive, which can effectively improve the defoaming property. The perfluoroalkyl chain in the molecular structure of the defoaming agent has a strong ability to reduce surface tension. When added to the original silicon wafer alkali polishing additive, it can quickly reduce the surface tension of the liquid, thereby destroying the stability of the foam; the defoaming agent can also penetrate into the liquid film of the foam, arrange and interact in a directional manner in the liquid film, so that the stability of the liquid film is destroyed, thereby causing the foam to burst; and the presence of the defoaming agent can also form a dense film on the liquid surface to prevent gas from escaping from the liquid and forming new foam.

[0035] 3. The present invention adds the prepared antifouling bactericide to the original silicon wafer alkali polishing additive, which can effectively improve its antifouling and bactericidal performance. The antifouling bactericide can chemically react or physically adsorb with the pollutants on the surface of the silicon wafer to form chemical bonds or physical connections, thereby preventing the attachment and deposition of pollutants. The formed protective film has low surface energy, which can reduce the contact area and interaction force between the pollutants and the silicon wafer surface, and further prevent the attachment of pollutants. The structure contained in the antifouling bactericide can destroy the cell wall or cell membrane of bacteria, resulting in the leakage of internal substances of bacteria or cell death, and can also interfere with the metabolic process of bacteria, inhibit enzyme activity, interfere with DNA replication and affect bacterial respiration, inhibit bacterial growth and reproduction, and achieve the purpose of sterilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 is a ZETA diagram of a silicon wafer processed by the method of Example 1;

[0038] Figure 2 is a ZETA diagram of a silicon wafer processed by the method of Comparative Example 1;

[0039] Figure 3 is a ZETA diagram of a silicon wafer processed by the method of Comparative Example 2;

[0040] Figure 4 is a ZETA·3D scan of a silicon wafer processed by the method of Comparative Example 1;

[0041] Figure 5 is a ZETA·3D scan of a silicon wafer processed by the method of Comparative Example 1;

[0042] Figure 6 This is a ZETA·3D scan of a silicon wafer processed by the method of Comparative Example 2. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Example 1: This example discloses a method for preparing a defoaming agent, comprising the following steps:

[0045] Q1: Add 5.5 g of N,N-diethyl-1,4-phenylenediamine and 5.2 g of triethylamine to a container, then add 62.5 mL of ether, and slowly drop 19.5 g of 2-methoxyethyl while stirring under an ice-water bath. The dropping time is controlled to be 1 h. After the dropping is completed, react at room temperature for 2 h, then heat at 50 ° C to react for 4 h. After the reaction is completed, evaporate the mixture, wash with deionized water, and dry at 60 ° C for 12 h to obtain intermediate 1;

[0046] Q2: Add 3.75g of chloroacetic acid and 1.55g of sodium hydroxide to 12.5mL of distilled water, stir and dissolve to obtain a mixed solution, then add 17.4g of intermediate 1 to 62.5mL of acetone, stir and dissolve, then add to the mixed solution, heat to reflux at 70℃ for 4h, after reflux, rotary evaporate, dissolve with anhydrous ethanol, filter, and distill under reduced pressure to obtain a crude product, continue to dissolve the crude product with anhydrous ethanol, add to ether for recrystallization, filter, and obtain a defoaming agent.

[0047] This embodiment discloses a method for preparing an antifouling bactericide, comprising the following steps:

[0048] S1: Add 77g of phenylhydrazine, 72.5g of malonic acid and 100mL of methanol to a container equipped with an electric stirrer and a spherical condenser, then add 12.5g of sodium to 80mL of methanol, stir to dissolve and then add dropwise to the container. After the addition is complete, heat to 70°C and reflux to react for 10h. After the reaction is complete, filter, rotary evaporate, wash with ice methanol, filter by suction, and dry to obtain intermediate A;

[0049] S2: 3 g of intermediate A, 70 mL of boron trifluoride etherate and 2.8 g of acetyl chloride were added to a container, heated and stirred at 95°C for 8 h, 0.95 g of acetyl chloride was added and the reaction was continued for 3 h. After the reaction was completed, the mixture was cooled and poured into ice water, extracted with ethyl acetate, the organic layers were combined, extracted with saturated sodium hydroxide solution, the pH was adjusted to 2 with 2 mol / L hydrochloric acid, rotary evaporated, washed with ethanol, filtered, ethanol was added to the filtrate, and then 1.5 g of 4-chlorophenylhydrazine was added, heated at 50°C for 3 h to dissolve, cooled to 35°C for reaction for 12 h, filtered, and intermediate B was obtained;

[0050] S3: Add 0.95g of intermediate B to a container filled with 10mL of dichloromethane, stir in an ice bath, add 0.22g of triethylamine and 0.23g of ethyl chloroformate to 5mL of dichloromethane, stir to dissolve, and slowly add dropwise to the container. After the addition is completed, react at 5°C for 6h, wash with 1mol / L hydrochloric acid and 5wt% sodium hydroxide solution, dry, and rotary evaporate. Recrystallize with a mixed solution of ether and petroleum ether in a volume ratio of 3:1, filter, and obtain an antifouling bactericidal agent.

[0051] This embodiment discloses a method for preparing an alkali polishing additive for raw silicon wafers, comprising the following steps:

[0052] Step 1: 2.25 g of defoamer, 2.25 g of sodium pyrosulfite, 1.25 g of pyridine-3-carboxylic acid, 0.2 g of citric acid, 0.075 g of sodium benzoate, 0.045 g of brown pigment, 1.06 g of antifouling bactericide and 92.3 mL of deionized water are mixed and stirred until there are no solid particles to obtain a mixture;

[0053] Step 2: Let the mixture stand until the foam disappears completely, filter it, and obtain the original silicon wafer alkali polishing additive.

[0054] This embodiment discloses a method for using an alkali polishing additive for raw silicon wafers, comprising the following steps:

[0055] Step (1): adding the prepared raw silicon wafer alkali polishing additive to a sodium hydroxide solution having a mass fraction of 4 wt %, wherein the amount ratio of the raw silicon wafer alkali polishing additive to the sodium hydroxide solution is 1.6 g:102.5 mL, and after being fully mixed, an alkali polishing solution is obtained;

[0056] Step (2): Add the original silicon wafer into an alkaline polishing solution and polish it at 80° C. for 4 minutes to obtain a smooth and flat silicon wafer.

[0057] Example 2: This example discloses a method for preparing a defoaming agent, comprising the following steps:

[0058] Q1: 5.2 g of N,N-diethyl-1,4-phenylenediamine and 5.4 g of triethylamine were added to a container, followed by 50 mL of ether. Under an ice-water bath, 18.8 g of 2-methoxyethyl was slowly added dropwise while stirring. The addition time was controlled to be 1 h. After the addition was completed, the reaction was carried out at room temperature for 2 h, and then at 50 °C for 4 h. After the reaction was completed, the reaction was carried out by rotary evaporation, washed with deionized water, and dried at 60 °C for 12 h to obtain intermediate 1.

[0059] Q2: Add 4.5g of chloroacetic acid and 2.1g of sodium hydroxide to 15mL of distilled water, stir and dissolve to obtain a mixed solution, then add 16g of intermediate 1 to 75mL of acetone, stir and dissolve, then add to the mixed solution, heat to reflux at 70℃ for 4h, after reflux, rotary evaporate, dissolve with anhydrous ethanol, filter, and distill under reduced pressure to obtain a crude product, continue to dissolve the crude product with anhydrous ethanol, add to ether for recrystallization, and filter to obtain a defoaming agent.

[0060] This embodiment discloses a method for preparing an antifouling bactericide, comprising the following steps:

[0061] S1: Add 54g of phenylhydrazine, 55g of malonic acid and 100mL of methanol to a container equipped with an electric stirrer and a spherical condenser, then add 15g of sodium to 80mL of methanol, stir to dissolve and then add dropwise to the container. After the addition is complete, heat to 70°C and reflux to react for 10h. After the reaction is complete, filter, rotary evaporate, wash with ice methanol, filter by suction, and dry to obtain intermediate A;

[0062] S2: 2 g of intermediate A, 50 mL of boron trifluoride etherate and 2.4 g of acetyl chloride were added to a container, heated and stirred at 95°C for 8 h, 1.1 g of acetyl chloride was added and the reaction was continued for 3 h. After the reaction was completed, the mixture was cooled and poured into ice water, extracted with ethyl acetate, the organic layers were combined, extracted with saturated sodium hydroxide solution, the pH was adjusted to 2 with 2 mol / L hydrochloric acid, rotary evaporated, washed with ethanol, filtered, ethanol was added to the filtrate, and then 1.8 g of 4-chlorophenylhydrazine was added, heated at 50°C for 3 h to dissolve, cooled to 35°C for reaction for 12 h, filtered, and intermediate B was obtained;

[0063] S3: Add 0.5g of intermediate B to a container filled with 10mL of dichloromethane, stir in an ice bath, add 0.17g of triethylamine and 0.17g of ethyl chloroformate to 5mL of dichloromethane, stir to dissolve, and slowly add dropwise to the container. After the addition is completed, react at 5°C for 6h, wash with 1mol / L hydrochloric acid and 5wt% sodium hydroxide solution, dry, and rotary evaporate, recrystallize with a mixed solution of ether and petroleum ether in a volume ratio of 3:1, and filter to obtain an antifouling bactericidal agent.

[0064] This embodiment discloses a method for preparing an alkali polishing additive for raw silicon wafers, comprising the following steps:

[0065] Step 1: 0.5 g of defoamer, 0.5 g of sodium pyrosulfite, 0.5 g of pyridine-3-carboxylic acid, 0.1 g of citric acid, 0.05 g of sodium benzoate, 0.04 g of brown pigment, 2 g of antifouling bactericide and 90.2 mL of deionized water are mixed and stirred until there are no solid particles to obtain a mixture;

[0066] Step 2: Let the mixture stand until the foam disappears completely, filter it, and obtain the original silicon wafer alkali polishing additive.

[0067] This embodiment discloses a method for using an alkali polishing additive for raw silicon wafers, comprising the following steps:

[0068] Step (1): adding the prepared raw silicon wafer alkali polishing additive to a sodium hydroxide solution having a mass fraction of 4 wt %, wherein the amount ratio of the raw silicon wafer alkali polishing additive to the sodium hydroxide solution is 0.2 g:105 mL, and after fully mixing, an alkali polishing solution is obtained;

[0069] Step (2): Add the original silicon wafer into an alkaline polishing solution and polish it at 80° C. for 4 minutes to obtain a smooth and flat silicon wafer.

[0070] Example 3: This example discloses a method for preparing a defoaming agent, comprising the following steps:

[0071] Q1: Add 5.8g of N,N-diethyl-1,4-phenylenediamine and 5g of triethylamine to a container, then add 75mL of ether, and slowly drop 20.2g of 2-methoxyethyl while stirring under ice-water bath conditions. The dropping time is controlled to be 1h. After the dropping is completed, react at room temperature for 2h, then heat at 50°C for 4h. After the reaction is completed, evaporate the mixture, wash with deionized water, and dry at 60°C for 12h to obtain intermediate 1;

[0072] Q2: Add 2 g of chloroacetic acid and 1.2 g of sodium hydroxide to 10 mL of distilled water, stir and dissolve to obtain a mixed solution, then add 18.8 g of intermediate 1 to 50 mL of acetone, stir and dissolve, then add to the mixed solution, heat to reflux at 70°C for 4 h, after reflux, rotary evaporate, dissolve with anhydrous ethanol, filter, and distill under reduced pressure to obtain a crude product, continue to dissolve the crude product with anhydrous ethanol, add to ether for recrystallization, and filter to obtain a defoaming agent.

[0073] This embodiment discloses a method for preparing an antifouling bactericide, comprising the following steps:

[0074] S1: Add 100g of phenylhydrazine, 90g of malonic acid and 100mL of methanol to a container equipped with an electric stirrer and a spherical condenser, then add 11g of sodium to 80mL of methanol, stir to dissolve and then add dropwise to the container. After the addition is complete, heat to 70°C and reflux to react for 10h. After the reaction is complete, filter, rotary evaporate, wash with ice methanol, filter by suction, and dry to obtain intermediate A;

[0075] S2: 4 g of intermediate A, 90 mL of boron trifluoride etherate and 3.2 g of acetyl chloride were added to a container, heated and stirred at 95°C for 8 h, 0.8 g of acetyl chloride was added and the reaction was continued for 3 h. After the reaction was completed, the mixture was cooled and poured into ice water, extracted with ethyl acetate, the organic layers were combined, extracted with saturated sodium hydroxide solution, the pH was adjusted to 2 with 2 mol / L hydrochloric acid, rotary evaporated, washed with ethanol, filtered, ethanol was added to the filtrate, and then 1.2 g of 4-chlorophenylhydrazine was added, heated at 50°C for 3 h to dissolve, cooled to 35°C for reaction for 12 h, filtered, and intermediate B was obtained;

[0076] S3: Add 1.2g of intermediate B to a container filled with 10mL of dichloromethane, stir in an ice bath, add 0.38g of triethylamine and 0.39g of ethyl chloroformate to 5mL of dichloromethane, stir to dissolve, and slowly add dropwise to the container. After the addition is completed, react at 5°C for 6h, wash with 1mol / L hydrochloric acid and 5wt% sodium hydroxide solution, dry, and rotary evaporate, recrystallize with a mixed solution of ether and petroleum ether in a volume ratio of 3:1, and filter to obtain an antifouling bactericidal agent.

[0077] This embodiment discloses a method for preparing an alkali polishing additive for raw silicon wafers, comprising the following steps:

[0078] Step 1: 4 g of defoamer, 4 g of sodium pyrosulfite, 3 g of pyridine-3-carboxylic acid, 0.3 g of citric acid, 0.1 g of sodium benzoate, 0.05 g of brown pigment, 0.12 g of antifouling bactericide and 94.6 mL of deionized water are mixed and stirred until there are no solid particles to obtain a mixture;

[0079] Step 2: Let the mixture stand until the foam disappears completely, filter it, and obtain the original silicon wafer alkali polishing additive.

[0080] This embodiment discloses a method for using an alkali polishing additive for raw silicon wafers, comprising the following steps:

[0081] Step (1): adding the prepared raw silicon wafer alkali polishing additive to a sodium hydroxide solution having a mass fraction of 4 wt %, wherein the amount ratio of the raw silicon wafer alkali polishing additive to the sodium hydroxide solution is 3 g:100 mL, and after fully mixing, an alkali polishing solution is obtained;

[0082] Step (2): Add the original silicon wafer into an alkaline polishing solution and polish it at 80° C. for 4 minutes to obtain a smooth and flat silicon wafer.

[0083] Example 4: This example discloses a method for preparing a defoaming agent, comprising the following steps:

[0084] Q1: 5.4 g of N,N-diethyl-1,4-phenylenediamine and 5.1 g of triethylamine were added to a container, followed by 55 mL of ether. Under an ice-water bath, 19.3 g of 2-methoxyethyl was slowly added dropwise while stirring. The addition time was controlled to be 1 h. After the addition was completed, the reaction was carried out at room temperature for 2 h, and then at 50 °C for 4 h. After the reaction was completed, the reaction was carried out by rotary evaporation, washed with deionized water, and dried at 60 °C for 12 h to obtain intermediate 1.

[0085] Q2: Add 3.5g of chloroacetic acid and 1.6g of sodium hydroxide to 11mL of distilled water, stir and dissolve to obtain a mixed solution, then add 16.2g of intermediate 1 to 55mL of acetone, stir and dissolve, then add to the mixed solution, heat to reflux at 70℃ for 4h, after reflux, rotary evaporate, dissolve with anhydrous ethanol, filter, and distill under reduced pressure to obtain a crude product, continue to dissolve the crude product with anhydrous ethanol, add to ether for recrystallization, and filter to obtain a defoaming agent.

[0086] This embodiment discloses a method for preparing an antifouling bactericide, comprising the following steps:

[0087] S1: Add 62g of phenylhydrazine, 62g of malonic acid and 100mL of methanol to a container equipped with an electric stirrer and a spherical condenser, then add 14g of sodium to 80mL of methanol, stir to dissolve and then add dropwise to the container. After the addition is complete, heat to 70°C and reflux to react for 10h. After the reaction is complete, filter, rotary evaporate, wash with ice methanol, filter by suction, and dry to obtain intermediate A;

[0088] S2: 2.5 g of intermediate A, 60 mL of boron trifluoride etherate and 2.6 g of acetyl chloride were added to a container, heated and stirred at 95°C for 8 h, 0.9 g of acetyl chloride was added and the reaction was continued for 3 h. After the reaction was completed, the mixture was cooled and poured into ice water, extracted with ethyl acetate, the organic layers were combined, extracted with saturated sodium hydroxide solution, the pH was adjusted to 2 with 2 mol / L hydrochloric acid, rotary evaporated, washed with ethanol, filtered, ethanol was added to the filtrate, and then 1.3 g of 4-chlorophenylhydrazine was added, heated at 50°C for 3 h to dissolve, cooled to 35°C for reaction for 12 h, filtered, and intermediate B was obtained;

[0089] S3: Add 0.72g of intermediate B to a container filled with 10mL of dichloromethane, stir in an ice bath, add 0.19g of triethylamine and 0.19g of ethyl chloroformate to 5mL of dichloromethane, stir to dissolve, and slowly add dropwise to the container. After the addition is completed, react at 5°C for 6h, wash with 1mol / L hydrochloric acid and 5wt% sodium hydroxide solution, dry, and rotary evaporate, recrystallize with a mixed solution of ether and petroleum ether in a volume ratio of 3:1, and filter to obtain an antifouling bactericidal agent.

[0090] This embodiment discloses a method for preparing an alkali polishing additive for raw silicon wafers, comprising the following steps:

[0091] Step 1: 1.5 g of defoamer, 1.8 g of sodium pyrosulfite, 0.9 g of pyridine-3-carboxylic acid, 0.15 g of citric acid, 0.06 g of sodium benzoate, 0.042 g of brown pigment, 0.34 g of antifouling bactericide and 91.3 mL of deionized water are mixed and stirred until there are no solid particles to obtain a mixture;

[0092] Step 2: Let the mixture stand until the foam disappears completely, filter it, and obtain the original silicon wafer alkali polishing additive.

[0093] This embodiment discloses a method for using an alkali polishing additive for raw silicon wafers, comprising the following steps:

[0094] Step (1): adding the prepared raw silicon wafer alkali polishing additive to a sodium hydroxide solution having a mass fraction of 4 wt %, wherein the amount ratio of the raw silicon wafer alkali polishing additive to the sodium hydroxide solution is 1.5 g:101 mL, and after being fully mixed, an alkali polishing solution is obtained;

[0095] Step (2): Add the original silicon wafer into an alkaline polishing solution and polish it at 80° C. for 4 minutes to obtain a smooth and flat silicon wafer.

[0096] Example 5: This example discloses a method for preparing a defoaming agent, comprising the following steps:

[0097] Q1: 5.6 g of N,N-diethyl-1,4-phenylenediamine and 5.3 g of triethylamine were added to a container, followed by 65 mL of ether. Under an ice-water bath, 20.1 g of 2-methoxyethyl was slowly added dropwise while stirring. The addition time was controlled to be 1 h. After the addition was completed, the reaction was carried out at room temperature for 2 h, and then at 50 °C for 4 h. After the reaction was completed, the reaction was carried out by rotary evaporation, washed with deionized water, and dried at 60 °C for 12 h to obtain intermediate 1.

[0098] Q2: Add 4.2g of chloroacetic acid and 1.4g of sodium hydroxide to 14mL of distilled water, stir and dissolve to obtain a mixed solution, then add 18.1g of intermediate 1 to 65mL of acetone, stir and dissolve, then add to the mixed solution, heat to reflux at 70℃ for 4h, after reflux, rotary evaporate, dissolve with anhydrous ethanol, filter, and distill under reduced pressure to obtain a crude product, continue to dissolve the crude product with anhydrous ethanol, add to ether for recrystallization, filter, and obtain a defoaming agent.

[0099] This embodiment discloses a method for preparing an antifouling bactericide, comprising the following steps:

[0100] S1: 83 g of phenylhydrazine, 88 g of malonic acid and 100 mL of methanol were added to a container equipped with an electric stirrer and a spherical condenser, and then 10 g of sodium was added to 80 mL of methanol, stirred to dissolve and then added dropwise to the container. After the addition was completed, the mixture was heated to 70°C and refluxed for 10 h. After the reaction was complete, it was filtered, rotary evaporated, washed with ice methanol, filtered, and dried to obtain intermediate A;

[0101] S2: 3.5 g of intermediate A, 80 mL of boron trifluoride etherate and 3 g of acetyl chloride were added to a container, heated and stirred at 95°C for 8 h, 1 g of acetyl chloride was added and the reaction was continued for 3 h. After the reaction was completed, the mixture was cooled and poured into ice water, extracted with ethyl acetate, the organic layers were combined, extracted with saturated sodium hydroxide solution, the pH was adjusted to 2 with 2 mol / L hydrochloric acid, rotary evaporated, washed with ethanol, filtered, ethanol was added to the filtrate, and then 1.6 g of 4-chlorophenylhydrazine was added, heated at 50°C for 3 h to dissolve, cooled to 35°C for reaction for 12 h, filtered, and intermediate B was obtained;

[0102] S3: Add 1.03g of intermediate B to a container filled with 10mL of dichloromethane, stir in an ice bath, add 0.26g of triethylamine and 0.26g of ethyl chloroformate to 5mL of dichloromethane, stir to dissolve, and slowly add dropwise to the container. After the addition is completed, react at 5°C for 6h, wash with 1mol / L hydrochloric acid and 5wt% sodium hydroxide solution, dry, and rotary evaporate. Recrystallize with a mixed solution of ether and petroleum ether in a volume ratio of 3:1, filter, and obtain an antifouling bactericidal agent.

[0103] This embodiment discloses a method for preparing an alkali polishing additive for raw silicon wafers, comprising the following steps:

[0104] Step 1: 3.7 g of defoamer, 2.9 g of sodium pyrosulfite, 1.8 g of pyridine-3-carboxylic acid, 0.25 g of citric acid, 0.09 g of sodium benzoate, 0.048 g of brown pigment, 1.87 g of antifouling bactericide and 93.8 mL of deionized water are mixed and stirred until there are no solid particles to obtain a mixture;

[0105] Step 2: Let the mixture stand until the foam disappears completely, filter it, and obtain the original silicon wafer alkali polishing additive.

[0106] This embodiment discloses a method for using an alkali polishing additive for raw silicon wafers, comprising the following steps:

[0107] Step (1): adding the prepared raw silicon wafer alkali polishing additive to a sodium hydroxide solution having a mass fraction of 4 wt %, wherein the amount ratio of the raw silicon wafer alkali polishing additive to the sodium hydroxide solution is 2.7 g:104 mL, and after being fully mixed, an alkali polishing solution is obtained;

[0108] Step (2): Add the original silicon wafer into an alkaline polishing solution and polish it at 80° C. for 4 minutes to obtain a smooth and flat silicon wafer.

[0109] Comparative Example 1: Compared with Example 1, in the treatment process of Comparative Example 1, no original silicon wafer alkali polishing additive is added to the alkali polishing solution, and other conditions remain unchanged.

[0110] Comparative Example 2: Compared with Example 1, in the treatment process of Comparative Example 2, only sodium metabisulfite is added to the alkaline polishing solution as the original silicon wafer alkaline polishing additive, and other conditions remain unchanged.

[0111] Experimental Example: The silicon wafers prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to performance tests, and the changes in the silicon wafers after polishing were observed. The degree of line marks on the silicon wafer tower base was evaluated, A for no obvious line marks, B for relatively obvious line marks, and C for obvious line marks; the surface flatness of the silicon wafer was evaluated, I for good surface flatness, II for fair surface flatness, and III for poor surface flatness. The reflectivity test system was used to measure the surface reflectivity of the silicon wafer, and the test results are shown in Table 1:

[0112] Table 1

[0113]

[0114]

[0115] From the test results in Table 1, it can be seen that the raw silicon wafer alkali polishing additives prepared in Examples 1-5 of the present invention have the performance of weakening line marks and improving the flatness of the polished surface. From the comparison between Comparative Examples 1-2 and Examples 1-5, it can be seen that the line marks of Examples 1-5 are all weakened, the surface flatness of the silicon wafer is good, the reflectivity is slightly higher, and the polishing effect is more excellent.

[0116] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0117] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing an alkali polishing additive for raw silicon wafers, characterized in that: The following steps are involved: Step 1: Mix the defoamer, active substance, surface brightener, pH adjuster, preservative, colorant, antifouling bactericide and deionized water, and stir thoroughly until there are no solid particles to obtain a mixture; Step 2: Let the mixture stand until the foam disappears completely, filter it, and obtain the original silicon wafer alkali polishing additive.

2. The method for preparing an alkali polishing additive for raw silicon wafers according to claim 1, characterized in that: In the step 1, the dosage ratio of the defoaming agent, active substance, surface brightener, pH regulator, preservative, colorant, antifouling bactericide and deionized water is (0.5-4) g: (0.5-4) g: (0.5-2) g: (0.1-0.3) g: (0.05-0.1) g: (0.04-0.05) g: (0.12-2) g: (90.2-94.6) mL.

3. The method for preparing an alkali polishing additive for raw silicon wafers according to claim 1, characterized in that: The preparation method of the defoamer comprises the following steps: Q1: Add N,N-diethyl-1,4-phenylenediamine and triethylamine to a container, then add diethyl ether, and slowly drop 2-methoxyethyl while stirring under ice-water bath conditions. Control the drop time. After the drop addition is complete, react at room temperature, then heat the reaction. After the reaction is complete, rotary evaporate, wash, and dry to obtain intermediate 1; Q2: Add chloroacetic acid and sodium hydroxide to distilled water, stir and dissolve to obtain a mixed solution, then add intermediate 1 to acetone, stir and dissolve, then add to the mixed solution, heat to reflux, after reflux, rotary evaporate, dissolve, filter, and distill under reduced pressure to obtain a crude product, continue to dissolve the crude product, recrystallize, and filter to obtain a defoaming agent.

4. The method for preparing an alkali polishing additive for raw silicon wafers according to claim 3, characterized in that: In the Q1, the amount ratio of N,N-diethyl-1,4-phenylenediamine, triethylamine, ether and 2-methoxyethyl is (5.2-5.8) g: (5-5.4) g: (50-75) mL: (18.8-20.2) g, the dropping time is controlled to be 1-2 h, the reaction is carried out at room temperature for 1-2 h, the heating reaction temperature is 40-50°C, the reaction time is 3-5 h, the reaction is washed with deionized water, the drying temperature is 50-70°C, and the time is 10-12 h.

5. The method for preparing an alkali polishing additive for raw silicon wafers according to claim 3, characterized in that: In Q2, the dosage ratio of chloroacetic acid, sodium hydroxide, distilled water, intermediate 1 and acetone is (3-4.5) g: (1.2-2.1) g: (10-15) mL: (16-18.8) g: (50-75) mL, the heating reflux temperature is 60-70°C, the time is 4-6 h, and it is dissolved in anhydrous ethanol. The crude product is further dissolved in anhydrous ethanol and added to ether for recrystallization.

6. The method for preparing an alkali polishing additive for raw silicon wafers according to claim 1, characterized in that: The active substance consists of one or more of alkyl glucoside, sodium pyrosulfite and sodium hypochlorite; the surface brightener consists of one or more of powdered sugar, pyridine-3-carboxylic acid, diatomaceous earth and sodium sulfate; the pH regulator consists of one or more of hydrochloric acid, citric acid, sodium hydroxide and potassium hydroxide; the preservative consists of one or more of sodium benzoate, potassium sorbate and dehydroacetic acid; and the colorant consists of one or more of brown pigment, caramel pigment and cocoa pigment.

7. The method for preparing an alkali polishing additive for raw silicon wafers according to claim 1, characterized in that: The preparation method of the antifouling bactericide comprises the following steps: S1: Phenylhydrazine, malonic acid and methanol are added to a container equipped with an electric stirrer and a spherical condenser, and then sodium is added to the methanol, stirred and dissolved, and then added dropwise to the container. After the addition is complete, the temperature is raised to reflux for reaction. After the reaction is complete, the mixture is filtered, rotary evaporated, washed, filtered, and dried to obtain intermediate A; S2: Add intermediate A, boron trifluoride etherate and acetyl chloride into a container, heat and stir, then add acetyl chloride to continue the reaction, cool after the reaction, pour into ice water, extract, combine the organic layers, extract, adjust the pH, rotary evaporate, wash, filter, add ethanol to the filtrate, then add 4-chlorophenylhydrazine, heat to dissolve, cool to react, filter, and obtain intermediate B; S3: Add intermediate B to a container filled with dichloromethane, stir in an ice bath, add triethylamine and ethyl chloroformate to dichloromethane, stir to dissolve, and slowly add dropwise to the container. After the addition is completed, react, wash, dry, rotary evaporate, recrystallize, and filter to obtain an antifouling bactericidal agent.

8. The method for preparing an alkali polishing additive for raw silicon wafers according to claim 7, characterized in that: In S1, the dosage ratio of phenylhydrazine, malonic acid and sodium is (54-100) g: (55-90) g: (10-15) g, the temperature of the reflux reaction is 60-70° C., the reaction time is 8-10 h, and the mixture is washed with ice methanol. In S2, the dosage ratio of intermediate A, boron trifluoride etherate, acetyl chloride added for the first time, acetyl chloride added for the second time and 4-chlorophenylhydrazine is (2-4) g: (50-90) mL: (2.4-3.2) g: (0.8-1.1) g: (1.2-1.8) g, heating and stirring temperature is 90-95 ° C, stirring time is 8-10h, continued reaction time is 2-3h, extracted with ethyl acetate, extracted with saturated sodium hydroxide solution, adjusted pH = 2-3 with 2mol / L hydrochloric acid, washed with ethanol, heated and dissolved at 40-60 ° C, time is 1-3h, cooled and reacted at 30-35 ° C, time is 10-12h.

9. The method for preparing an alkali polishing additive for raw silicon wafers according to claim 7, characterized in that: In the S3, the dosage ratio of the intermediate B, triethylamine and ethyl chloroformate is (0.5-1.2) g: (0.17-0.38) g: (0.17-0.39) g, the reaction temperature is 2-5°C, the reaction time is 4-6h, and the product is washed with 1 mol / L hydrochloric acid and 5 wt% sodium hydroxide solution, and recrystallized with a mixed solution of ether and petroleum ether in a volume ratio of 3:

1.

10. A method for using the raw silicon wafer alkali polishing additive according to claims 1-9, characterized in that: The following steps are involved: Step (1): adding the original silicon wafer alkali polishing additive to a sodium hydroxide solution with a mass fraction of 1-6wt%, wherein the amount ratio of the original silicon wafer alkali polishing additive to the sodium hydroxide solution is (0.2-3)g: (100-105)mL, and after sufficient mixing, an alkali polishing solution is obtained; Step (2): Add the original silicon wafer into an alkaline polishing solution and polish it at 60-80°C for 2-6 minutes to obtain a smooth and flat silicon wafer.

Images