Cleaning additive before texturing, cleaning agent before texturing, cleaning method and texturing method

Abstract

The invention relates to a pre-texturing cleaning additive, a pre-texturing cleaning agent, a cleaning method and a texturing method, in particular to the technical field of solar cell production, and the pre-texturing cleaning additive comprises a surfactant, an inorganic salt dispersant, a polymeric dispersant and a first solvent. According to the cleaning additive before texturing provided by the invention, the additive components are designed, so that the additive can completely replace hydrogen peroxide in an existing cleaning agent before texturing, and meanwhile, the uniformity of a textured surface obtained after texturing is obviously improved compared with that when the hydrogen peroxide is used as the component of the cleaning agent before texturing; the problem that the existing cleaning agent before texturing has different colors such as patterned wafers, raindrop marks and the like after the texturing process of the silicon wafer is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of solar cell production, and in particular to a pre-texturing cleaning additive, a pre-texturing cleaning agent, a cleaning method and a texturing method. Background Art

[0002] At present, texturing cleaning is an indispensable and important process in the production of photovoltaic solar cells, which mainly includes cleaning before texturing, texturing, cleaning after texturing, pickling, drying, etc. Cleaning before texturing is to remove the dirt on the surface of the silicon wafer, so that the silicon wafer can obtain a uniform velvet surface after texturing, avoiding the appearance of spots, fingerprints and other discoloration problems.

[0003] Before texturing, there are two main types of dirt on the surface of silicon wafers: one is organic stains, such as fingerprints, wire cutting fluid residues, etc.; the other is inorganic solid particles, such as silicon powder, dust, etc. During the texturing process, these dirt will hinder the chemical reaction between inorganic alkali and silicon wafers, causing uneven local corrosion, thus showing discoloration problems such as flower pieces and raindrops. Therefore, before texturing, the cleanliness of the silicon wafer surface must be guaranteed.

[0004] The current mainstream pre-texturing cleaning process is still a combination of low-concentration inorganic strong alkali and hydrogen peroxide, and the cleaning liquid temperature needs to be heated to about 70°C. This process has the following disadvantages: First, hydrogen peroxide is easily decomposed in a heated environment and cannot exist stably, so it is necessary to continuously add hydrogen peroxide to the cleaning liquid, resulting in an increase in process costs; second, hydrogen peroxide is a strong oxidizing substance and is dangerous to the human body. Therefore, it is of great significance to develop an additive that can replace hydrogen peroxide as a pre-texturing cleaning additive.

[0005] For example, CN103589538A discloses a cleaning liquid for solar silicon wafers and a method for using the same, wherein the cleaning liquid is composed of the following components in percentage by mass: 20-30% citric acid, 0.1-1% hydrofluoric acid, 5-20% hydrogen peroxide, 1-2% pH regulator, 10-25% surfactant, 2-5% dispersant, and the remainder is pure water. The invention is an acid cleaning agent, and the hydrofluoric acid used is not only dangerous, but also easily volatile, causing corrosion to the metal of the production equipment.

[0006] CN106833954A discloses an additive for a pre-cleaning liquid for texturing a single crystal silicon wafer, wherein the mass percentage of each component is: polyethylene glycol 1-20%, propylene glycol propyl ether 0.1-2.0%, hydrolyzed polymaleic anhydride 1.0-5.0%, and the balance is water. The cleaning liquid of the invention has an excellent cleaning effect on inorganic solid particles remaining on the surface of the silicon wafer, but cannot effectively remove stubborn grease dirt.

[0007] CN112940875A discloses a solar cell silicon wafer cleaning agent and a solar cell silicon wafer cleaning method. The solar cell silicon wafer cleaning agent is composed of 0.02-1.0% surfactant, 0.1-0.8% chelating agent, 0.02-1.0% complex enzyme, 0.03-2.0% salt and the balance of water according to weight percentage. The invention utilizes the combination of surfactant and complex enzyme to improve the cleaning ability of the cleaning liquid for grease dirt, but the cleaning ability for inorganic solid particles is poor.

[0008] In summary, the organic grease stains and inorganic solid particles remaining on the surface of silicon wafers before texturing cannot be removed simultaneously, and the removal effect is still poor, resulting in discoloration problems such as flower pieces and raindrop marks on the silicon wafers after the texturing process. Summary of the invention

[0009] In view of the problems existing in the prior art, the purpose of the present invention is to provide a pre-texturing cleaning additive, a pre-texturing cleaning agent, a cleaning method and a texturing method, so as to achieve effective cleaning of the surface of a silicon wafer, and solve the problem that when the cleaning additive is used to clean the silicon wafer before texturing, the organic grease stains and inorganic solid particles remaining on the surface of the silicon wafer cannot be removed at the same time, and the removal effect is poor, resulting in discoloration problems such as flower pieces and raindrop marks on the silicon wafer after the texturing process.

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] In a first aspect, the present invention provides a pre-texturing cleaning additive, which comprises: a surfactant, an inorganic salt dispersant, a polymer dispersant and a first solvent.

[0012] The pre-texturing cleaning additive provided by the present invention can completely replace the hydrogen peroxide in the existing pre-texturing cleaning agent through the design of the additive components. At the same time, compared with the use of hydrogen peroxide as the pre-texturing cleaning agent component, the uniformity of the velvet surface obtained after texturing is significantly improved, avoiding the existing pre-texturing cleaning agents The color problems such as flower pieces, raindrop marks, etc. after the silicon wafer texturing process are avoided.

[0013] As a preferred technical solution of the present invention, the pre-texturing cleaning additive comprises, by mass percentage, 5-25% of a surfactant, 3-10% of an inorganic salt dispersant, 1-5% of a polymer dispersant and a first solvent.

[0014] As a preferred technical solution of the present invention, the surfactant includes one or a combination of at least two of isomeric alcohol polyether carboxylates, isooctyl sulfates, fatty acid methyl ester ethoxylated sulfonates or diisooctyl sulfosuccinate.

[0015] Preferably, the inorganic salt dispersant includes one or a combination of at least two of sodium hexametaphosphate, trisodium phosphate, potassium pyrophosphate or sodium ethylenediaminetetraacetate.

[0016] Preferably, the polymer dispersant includes one or a combination of at least two of lignin sulfonate, carboxymethyl cellulose salt, sodium polyacrylate or polyvinyl pyrrolidone.

[0017] In a second aspect, the present invention provides a pre-texturing cleaning agent, which comprises: an alkali, a second solvent and the additive as described in the first aspect.

[0018] As a preferred technical solution of the present invention, the pre-texturing cleaning agent comprises an additive, an alkali and a second solvent in a mass ratio of (0.5-5):(0.1-0.5):100.

[0019] As a preferred technical solution of the present invention, the alkali includes potassium hydroxide and / or sodium hydroxide.

[0020] In a third aspect, the present invention provides a method for cleaning a silicon wafer before texturing, the cleaning method comprising cleaning the silicon wafer using the pre-texturing cleaning agent as described in the second aspect.

[0021] As a preferred technical solution of the present invention, the cleaning temperature is 60-80°C.

[0022] As a preferred technical solution of the present invention, the cleaning time is 2-5 minutes.

[0023] In a fourth aspect, the present invention provides a method for texturing a silicon wafer, the method comprising: cleaning the silicon wafer with the pre-texturing cleaning agent described in the second aspect, and then texturing the cleaned silicon wafer.

[0024] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0025] (1) Compared with the traditional hydrogen peroxide additive, the pre-texturing cleaning additive of the present invention has an excellent cleaning effect on organic grease stains and inorganic solid particles remaining on the surface of the silicon wafer, and the velvet surface of the silicon wafer obtained is more uniform and has a higher yield.

[0026] (2) The uniformity of the velvet surface will have a certain impact on the reflectivity, and the average reflectivity of the silicon wafer velvet surface produced by the present invention is slightly lower than the average reflectivity of the silicon wafer velvet surface produced by the traditional hydrogen peroxide solution. This can improve the absorption of photons by the silicon wafer velvet surface, enhance the light trapping effect, and thus improve the conversion efficiency of photovoltaic cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a photo of the silicon wafer after cleaning and texturing in Application Example 2 of the present invention;

[0028] Figure 2 This is a photo of the silicon wafer obtained after cleaning in Comparative Application Example 1 of the present invention after texturing;

[0029] Figure 3 This is a photo of the silicon wafer obtained after cleaning and texturing in Comparative Application Example 2 of the present invention;

[0030] Figure 4 This is a photograph of the silicon wafer obtained after cleaning in comparative application example 3 of the present invention after texturing.

[0031] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims. DETAILED DESCRIPTION

[0032] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0033] This embodiment provides a pre-texturing cleaning additive, which includes: a surfactant, an inorganic salt dispersant, a polymer dispersant and a first solvent.

[0034] In the present invention, the surfactant used in the pre-texturing cleaning additive significantly reduces the surface tension of the cleaning solution, peels off the organic grease stains from the surface of the silicon wafer and emulsifies and disperses them in the cleaning solution, and the reduction of the surface tension allows the inorganic salt dispersant in the cleaning solution to quickly wet and penetrate into the gap between the silicon wafer and the solid dirt, and separate the solid dirt from the silicon wafer surface under the action of the electrostatic effect, while the electrostatic effect and steric hindrance of the polymer dispersant further hinder the mutual attraction and re-aggregation between the solid dirt. In this way, the two major types of dirt on the surface of the silicon wafer are cleaned.

[0035] In the present invention, the raw materials used in the cleaning additives before texturing are all highly hydrophilic and are commonly used raw materials for texturing additives. They are not only easy to rinse, but also a layer of residual liquid adsorbed on the surface of the silicon wafer after rinsing is brought into the texturing tank, which can effectively make the texturing liquid spread quickly and evenly to all parts of the silicon wafer, and through synergistic effect, it can jointly increase the nucleation sites and the nucleation density with the nucleating agent in the texturing liquid, and finally obtain a silicon wafer with a uniform texturing surface.

[0036] It should be noted that the raw materials used in the present invention have good hydrophilicity and are easy to dissolve and disperse in water. That is, it is easy to rinse. Secondly, the rinsing water is pure water, etc., which can remove most of the cleaning liquid before texturing. Only a very small amount of cleaning liquid components will adhere to the surface of the silicon wafer together with the rinsing water, and thus enter the texturing tank. Finally, the surfactant contained in the texturing additive improves the wettability of the texturing liquid to the silicon wafer surface. The surfactant used in the present invention can further improve the rapid wetting of the silicon wafer surface by the texturing liquid, thereby obtaining a silicon wafer with a uniform velvet surface, that is, it plays a synergistic role. Furthermore, the actual surfactant content in the texturing tank is extremely low, far from reaching the upper limit of its addition amount, so as long as the cleaning liquid components themselves have no negative impact on the subsequent texturing, there is only one rinsing tank between the pre-texturing cleaning and the texturing in actual production, so this rinsing only needs to rinse out most of the cleaning liquid components, and a small amount will be brought into the texturing tank.

[0037] In the present invention, the preparation process of the pre-texturing cleaning additive is to mix the raw materials according to a defined ratio, for example, dissolving an inorganic salt dispersant and a polymer dispersant in water, then adding a surfactant and stirring evenly.

[0038] The pre-texturing cleaning additive comprises, by mass percentage, 5-25% of a surfactant, 3-10% of an inorganic salt dispersant, 1-5% of a polymer dispersant and a first solvent.

[0039] In the present invention, the mass percentage of the surfactant in the pre-texturing cleaning additive is 5-25%, for example, it can be 5%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24% or 25%, etc., but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0040] In the present invention, the mass percentage of the inorganic salt dispersant in the pre-texturing cleaning additive is 3-10%, for example, it can be 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%, etc., which are but not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0041] In the present invention, the mass percentage of the polymer dispersant in the pre-texturing cleaning additive is 1-5%, for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0042] The surfactant includes one or a combination of at least two of anionic surfactants such as isomeric alcohol polyether carboxylates, isooctyl sulfates, fatty acid methyl ester ethoxylated sulfonates or diisooctyl sulfosuccinate.

[0043] Illustratively, the combination may be a combination of isooctanol sulfate and fatty acid methyl ester ethoxylated sulfonate, a combination of fatty acid methyl ester ethoxylated sulfonate and diisooctyl sulfosuccinate, a combination of isooctanol sulfate and fatty acid methyl ester ethoxylated sulfonate, a combination of isooctanol carboxylate and fatty acid methyl ester ethoxylated sulfonate, a combination of isooctyl sulfosuccinate and the like.

[0044] In the present invention, the isomeric alcohol polyether carboxylate can be selected from commercially available isomeric decanol polyether carboxylate sodium IAEC-1008H and isomeric tridecanol polyether carboxylate sodium IAEC-1306H, and can also be prepared by the preparation method disclosed in the art.

[0045] In the present invention, the isooctyl sulfate can be selected from commercially available sodium isooctyl sulfate EHS, etc., or the isooctyl sulfate can be prepared by a preparation method disclosed in the art.

[0046] In the present invention, the fatty acid methyl ester ethoxylated sulfonate can be selected from commercially available fatty acid methyl ester ethoxylated sulfonate FMES, or the obtained fatty acid methyl ester ethoxylated sulfonate can be prepared by a preparation method disclosed in the art.

[0047] In the present invention, the diisooctyl sulfosuccinate salt can be selected from commercially available diisooctyl sulfosuccinate salt OT-75 and diisooctyl sulfosuccinate salt OT-45, and the diisooctyl sulfosuccinate salt can also be prepared by the preparation method disclosed in the art.

[0048] Wherein, the inorganic salt dispersant includes one or a combination of at least two of sodium hexametaphosphate, trisodium phosphate, potassium pyrophosphate or sodium ethylenediaminetetraacetate.

[0049] Exemplarily, the combination can be selected as a combination of sodium hexametaphosphate and trisodium phosphate, a combination of trisodium phosphate and potassium pyrophosphate, a combination of potassium pyrophosphate and sodium edetate, a combination of trisodium phosphate and sodium edetate, a combination of sodium hexametaphosphate and potassium pyrophosphate, etc.

[0050] The polymer dispersant includes one or a combination of at least two of lignin sulfonate, carboxymethyl cellulose salt, sodium polyacrylate or polyvinyl pyrrolidone.

[0051] In the present invention, the molecular weight of sodium polyacrylate is 1000-10000.

[0052] In the present invention, the polyvinyl pyrrolidone can be selected from commercially available products such as PVP K15, PVP K25, PVP K30 and PVP K60.

[0053] Exemplarily, the combination may be selected from a combination of lignin sulfonate and carboxymethyl cellulose salt, a combination of carboxymethyl cellulose salt and sodium polyacrylate, a combination of sodium polyacrylate and polyvinyl pyrrolidone, a combination of lignin sulfonate and sodium polyacrylate, and the like.

[0054] Furthermore, the present invention provides a cleaning agent before texturing, which comprises: an additive, an alkali and a second solvent.

[0055] In the present invention, an exemplary preparation process of the pre-texturing cleaning agent is to mix the additive, the alkali and the second solvent according to a ratio.

[0056] Among them, the pre-texturing cleaning agent includes an additive, an alkali and a second solvent in a mass ratio of (0.5-5):(0.1-0.5):100, for example, it can be 0.5:0.1:100, 1:0.1:100, 2:0.1:100, 3:0.1:100, 4:0.1:100, 5:0.1:100, 0.5:0.2:100, 0.5:0.3:100, 0.5:0.4:100, 0.5:0.5:100, 0.1:0.2:100, 2:0.3:100 or 5:0.5:100, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0057] Wherein, the alkali includes potassium hydroxide and / or sodium hydroxide.

[0058] In the present invention, the first solvent and the second solvent used in preparing the pre-texturing cleaning additive and the pre-texturing cleaning agent can be selected from water, alcohol and other commonly used solvents in the art.

[0059] Furthermore, the present invention provides a method for cleaning a silicon wafer before texturing, the cleaning method comprising using the aforementioned cleaning agent before texturing to clean the silicon wafer.

[0060] Among them, the cleaning temperature is 60-80℃, for example, it can be 60℃, 62℃, 64℃, 66℃, 68℃, 70℃, 72℃, 74℃, 76℃, 78℃ or 80℃, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0061] The cleaning time is 2-5 minutes, for example, 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes or 5 minutes, but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0062] Furthermore, the present invention provides a method for texturing a silicon wafer, the method comprising: cleaning the silicon wafer with a pre-texturing cleaning agent, and then texturing the cleaned silicon wafer.

[0063] Furthermore, in order to illustrate the effects that can be achieved by the pre-texturing cleaning additive provided by the present invention, actual examples are used for illustration, as follows:

[0064] Example 1

[0065] The embodiment of the present invention provides a pre-texturing cleaning additive, which comprises, by mass percentage, 5% surfactant, 10% inorganic salt dispersant, 1% polymer dispersant, and the remainder is solvent water.

[0066] The surfactant is sodium isomeric decanol polyether carboxylate IAEC-1008H;

[0067] The inorganic salt dispersant is sodium hexametaphosphate;

[0068] The polymer dispersant is sodium lignin sulfonate.

[0069] Example 2

[0070] The embodiment of the present invention provides a pre-texturing cleaning additive, which comprises, by mass percentage, 15% of a surfactant, 5% of an inorganic salt dispersant, 3% of a polymer dispersant, and the remainder being solvent water.

[0071] The surfactant is sodium isomeric tridecanol polyether carboxylate IAEC-1306H;

[0072] The inorganic salt dispersant is potassium pyrophosphate;

[0073] The polymer dispersant is sodium polyacrylate (molecular weight is 2000).

[0074] Example 3

[0075] The embodiment of the present invention provides a pre-texturing cleaning additive, which comprises, by mass percentage, 25% of a surfactant, 3% of an inorganic salt dispersant, 5% of a polymer dispersant, and the remainder being solvent water.

[0076] The surfactant is fatty acid methyl ester ethoxylated sodium sulfonate FMES;

[0077] The inorganic salt dispersant is sodium ethylenediaminetetraacetate;

[0078] The polymer dispersant is polyvinyl pyrrolidone (commercially available PVP K30).

[0079] Example 4

[0080] The embodiment of the present invention provides a pre-texturing cleaning additive, which comprises, by mass percentage, 20% of a surfactant, 5% of an inorganic salt dispersant, 3% of a polymer dispersant, and the remainder being solvent water.

[0081] The surfactant is isomeric tridecanol polyether carboxylate sodium IAEC-1306H and isooctyl sodium sulfate EHS in a mass ratio of 3:1;

[0082] The inorganic salt dispersant is trisodium phosphate;

[0083] The polymer dispersant is sodium polyacrylate (8000).

[0084] Example 5

[0085] The embodiment of the present invention provides a pre-texturing cleaning additive, which comprises, by mass percentage, 15% of a surfactant, 5% of an inorganic salt dispersant, 3% of a polymer dispersant, and the remainder being solvent water.

[0086] The surfactant includes sodium isomeric decanol polyether carboxylate IAEC-1008H;

[0087] The inorganic salt dispersant is trisodium phosphate;

[0088] The polymer dispersant is lignin sulfonate.

[0089] Example 6

[0090] The embodiment of the present invention provides a pre-texturing cleaning additive, which comprises, by mass percentage, 15% of a surfactant, 5% of an inorganic salt dispersant, 3% of a polymer dispersant, and the remainder being solvent water.

[0091] The surfactant is sodium isomeric tridecanol polyether carboxylate IAEC-1306H;

[0092] The inorganic salt dispersant is sodium hexametaphosphate;

[0093] The polymer dispersant is sodium carboxymethyl cellulose.

[0094] Application Example 1

[0095] This application example provides a cleaning process using a pre-texturing cleaning agent, wherein the pre-texturing cleaning agent includes an additive (from Example 1), an alkali, and water in a mass ratio of 2:0.2:100; the alkali is sodium hydroxide;

[0096] During the cleaning process of the silicon wafer, the cleaning temperature is 65°C and the cleaning time is 2 minutes.

[0097] Application Example 2

[0098] This application example provides a cleaning process using a pre-texturing cleaning agent, wherein the pre-texturing cleaning agent includes an additive (from Example 2), an alkali, and water in a mass ratio of 0.5:0.5:100; the alkali is potassium hydroxide;

[0099] During the cleaning process of the silicon wafer, the cleaning temperature is 70°C and the cleaning time is 3 minutes.

[0100] Application Example 3

[0101] This application example provides a cleaning process using a pre-texturing cleaning agent, wherein the pre-texturing cleaning agent includes an additive (from Example 3), an alkali, and water in a mass ratio of 5:0.1:100; the alkali is potassium hydroxide and sodium hydroxide in a mass ratio of 1:1;

[0102] During the cleaning process of the silicon wafer, the cleaning temperature is 60°C and the cleaning time is 5 minutes.

[0103] Application Example 4

[0104] This application example provides a cleaning process using a pre-texturing cleaning agent, wherein the pre-texturing cleaning agent includes an additive (from Example 4), an alkali, and water in a mass ratio of 1:0.2:100; the alkali is sodium hydroxide;

[0105] During the cleaning process of the silicon wafer, the cleaning temperature is 80°C and the cleaning time is 2 minutes.

[0106] Application Example 5

[0107] This application example provides a cleaning process using a pre-texturing cleaning agent, wherein the pre-texturing cleaning agent includes an additive (from Example 5), an alkali, and water in a mass ratio of 5:0.3:100; the alkali is potassium hydroxide;

[0108] During the cleaning process of the silicon wafer, the cleaning temperature is 60°C and the cleaning time is 3 minutes.

[0109] Application Example 6

[0110] This application example provides a cleaning process using a pre-texturing cleaning agent, wherein the pre-texturing cleaning agent includes an additive (from Example 6), an alkali, and water in a mass ratio of 4:0.2:100; the alkali is sodium hydroxide;

[0111] During the cleaning process of the silicon wafer, the cleaning temperature is 70°C and the cleaning time is 2 minutes.

[0112] Comparative application example 1

[0113] The only difference from Application Example 1 is that the additive is replaced by an equal amount of hydrogen peroxide with a mass concentration of 32%.

[0114] Comparative Application Example 2

[0115] The only difference from Application Example 1 is that sodium hydroxide is replaced by an equimolar amount of sulfuric acid.

[0116] Comparative Application Example 3

[0117] The only difference from Application Example 1 is that the inorganic salt dispersant in the additive is replaced with an equal amount of polymer dispersant.

[0118] Comparative Application Example 4

[0119] The only difference from Application Example 1 is that the polymer dispersant in the additive is replaced with an equal amount of inorganic salt dispersant.

[0120] Comparative Application Example 5

[0121] The only difference from Application Example 1 is that the surfactant in the additive is replaced by an equal amount of Tween 80.

[0122] Application Example 7

[0123] The only difference from Application Example 1 is that the percentage of the surfactant in the additive is 3%.

[0124] Application Example 8

[0125] The only difference from Application Example 1 is that the percentage of the surfactant in the additive is 30%.

[0126] Application Example 9

[0127] The only difference from Application Example 1 is that the amount of the inorganic salt dispersant added in the additive is 2%.

[0128] Application Example 10

[0129] The only difference from Application Example 1 is that the amount of the inorganic salt dispersant added in the additive is 14%.

[0130] Application Example 11

[0131] The only difference from Application Example 1 is that the amount of the polymer dispersant added in the additive is 0.5%.

[0132] Application Example 12

[0133] The only difference from Application Example 1 is that the amount of the polymer dispersant added in the additive is 8%.

[0134] Application Example 13

[0135] The only difference from Application Example 1 is that the mass ratio of the additive, the alkali and the second solvent in the pre-texturing cleaning agent is 0.1:0.2:100.

[0136] Application Example 14

[0137] The only difference from Application Example 1 is that the mass ratio of the additive, the alkali and the second solvent in the pre-texturing cleaning agent is 8:0.2:100.

[0138] The cleaned silicon wafers of the application examples and the comparative application examples are subjected to texturing, for example: the cleaned silicon wafers are soaked in deionized water at room temperature for 2 minutes; then the rinsed silicon wafers are vertically soaked in the texturing solution at 80°C for 7 minutes, then the texturing silicon wafers are soaked in deionized water at room temperature for 2 minutes; then the rinsed silicon wafers are soaked in the post-texturing cleaning solution at 65°C for 2 minutes; then the cleaned silicon wafers are soaked in deionized water at room temperature for 2 minutes; then the rinsed silicon wafers are soaked in the pickling solution at room temperature for 2 minutes, then the pickled silicon wafers are placed in hot water at 80°C and slowly pulled up; then the slowly pulled silicon wafers are placed in an oven for drying, to obtain the texturing-treated silicon wafers.

[0139] The texture yield and reflectivity of the silicon wafers after texturing are tested; the texture yield is to observe and compare the uniformity of the texture of the silicon wafer; the reflectivity of the silicon wafer is measured with a D8 reflectivity meter, and the average reflectivity is calculated. For each example, 500 silicon wafers are processed respectively, and then the number of silicon wafers with poor texture after texturing (the surface of the silicon wafer is uneven, and there are some dots or blocks of different colors) is counted, and the texture yield is calculated. The results are shown in Table 1 below.

[0140] Table 1

[0141]

[0142]

[0143] As can be seen from Table 1, compared with Comparative Application Example 1, the silicon wafer velvet yield obtained in Application Examples 1-6 is higher, and the average reflectivity of the velvet is also slightly reduced. Compared with Application Example 1, the amount of inorganic salt dispersant added in Comparative Application Example 2 and Application Example 9 is too low or not added, resulting in insufficient cleaning power for some solid particles on the surface of the silicon wafer, so the velvet yield is reduced. Compared with Application Example 1, the amount of polymer dispersant added in Comparative Application Example 3 and Application Example 11 is too low or not added, resulting in solid particles more easily re-aggregated on the surface of the silicon wafer. Compared with Application Example 1, the performance of the surfactant used in Comparative Application Example 4 is poor, there is no good cleaning effect, the velvet yield is low, and the average reflectivity of the velvet is too high. Compared with Application Example 1, the amount of surfactant added in Application Example 7 is too small, resulting in insufficient cleaning power in the later stage. Compared with Application Example 1, the amount of surfactant added in Application Example 8 is too high. Although it has a good cleaning effect and a high velvet yield, when the excessive amount of surfactant is adsorbed on the surface of the silicon wafer and brought into the velvet making tank, it will hinder the velvet making reaction process of the silicon wafer, so the average reflectivity of the velvet increases. Compared with Application Example 1, the amount of dispersant added in Application Examples 10 and 12 is too high, which has a certain impact on the overall compound synergistic effect of the components of the cleaning solution, and when the polymer dispersant is excessive, it will also have a certain hindering effect on the velvet making reaction process. Application Example 13 is because the added amount is too low, resulting in incomplete cleaning, so the average reflectivity of the velvet increases; and Application Example 14 is because the residual adsorption of the added amount component on the surface of the silicon wafer is excessive, which hinders the velvet making reaction process, so the average reflectivity of the velvet increases, but the velvet yield is relatively high.

[0144] Further, by Figure 1 and Figure 2 , Figure 3 , Figure 4 By comparison, it can be seen that the velvet surface of the silicon wafer after cleaning using Application Example 2 has a uniform appearance without fingerprints or other discoloration problems. The velvet surface of the silicon wafer after cleaning using Comparative Application Example 1, Comparative Application Example 2, and Comparative Application Example 3 has fingerprints, raindrops, and other discoloration defects.

[0145] It is stated that the present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0146] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0147] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0148] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A pre-texturing cleaning additive, characterized in that: The pre-texturing cleaning additive comprises: a surfactant, an inorganic salt dispersant, a polymer dispersant and a first solvent.

2. The pre-texturing cleaning additive according to claim 1, characterized in that: The pre-texturing cleaning additive comprises, by mass percentage, 5-25% of a surfactant, 3-10% of an inorganic salt dispersant, 1-5% of a polymer dispersant and a first solvent.

3. The pre-texturing cleaning additive according to claim 1 or 2, characterized in that: The surfactant comprises one or a combination of at least two of isomeric alcohol polyether carboxylates, isooctyl sulfates, fatty acid methyl ester ethoxylated sulfonates or diisooctyl sulfosuccinate; Preferably, the inorganic salt dispersant includes one or a combination of at least two of sodium hexametaphosphate, trisodium phosphate, potassium pyrophosphate or sodium ethylenediaminetetraacetate; Preferably, the polymer dispersant includes one or a combination of at least two of lignin sulfonate, carboxymethyl cellulose salt, sodium polyacrylate or polyvinyl pyrrolidone.

4. A pre-texturing cleaning agent, characterized in that: The pre-texturing cleaning agent comprises: an alkali, a second solvent and the additive as described in any one of claims 1-3.

5. The pre-texturing cleaning agent according to claim 4, characterized in that: The pre-texturing cleaning agent comprises an additive, an alkali and a second solvent in a mass ratio of (0.5-5):(0.1-0.5):

100.

6. The pre-texturing cleaning agent according to claim 4 or 5, characterized in that: The base includes potassium hydroxide and / or sodium hydroxide.

7. A method for cleaning a silicon wafer before texturing, characterized in that: The cleaning method comprises cleaning the silicon wafer using the pre-texturing cleaning agent as described in any one of claims 4-6.

8. The cleaning method according to claim 7, characterized in that: The cleaning temperature is 60-80°C.

9. The cleaning method according to claim 7 or 8, characterized in that: The cleaning time is 2-5 minutes.

10. A method for texturing a silicon wafer, characterized in that: The texturing method comprises: cleaning the silicon wafer with the pre-texturing cleaning agent as described in any one of claims 4 to 6, and then texturing the cleaned silicon wafer.

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