Cleaning agent as well as preparation method and application thereof

Abstract

The invention provides a cleaning agent as well as a preparation method and application thereof. The cleaning agent comprises alkyl glycoside, iminodisuccinic acid, inorganic alkali and water. The cleaning agent has the advantages of being good in stability, high in decontamination rate, low in residual metal element content and low in re-washing rate at the same time, and damage to the surface of the silicon wafer material can be reduced while pollutants on the surface of the silicon wafer material are removed, so that the cleaning efficiency of the silicon wafer material is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of photovoltaic product processing, and specifically relates to a cleaning agent and a preparation method and application thereof. Background Art

[0002] With the rapid development of the solar photovoltaic industry, the requirements for cleaning in the silicon wafer material manufacturing process are constantly increasing, and the cleaning agent is required to have a better decontamination ability. CN 108300583A discloses a silicon wafer cleaning agent, which contains a chelating agent, an active agent, a soluble alkali, an alcohol additive, a defoaming agent, a substrate wetting agent, an antioxidant and deionized water, which can reduce the proportion of chipping, cracking and dirt on the silicon wafer, and no black edges appear after cleaning. The silicon wafer is not easily oxidized during the cleaning process. CN 10853131297A discloses an environmentally friendly silicon wafer cleaning agent, which includes water, alkali, a surfactant, a rust inhibitor, a chelating agent, a dispersant, a bactericide and a defoaming agent, has good cleaning performance and low use cost. However, the above-mentioned cleaning agent has the problems of poor decontamination ability, high residual metal element content and high backwash rate.

[0003] Therefore, how to provide a cleaning agent with good stability, high dirt removal rate, low residual metal element content and low backwash rate is a technical problem to be solved urgently in this field. Summary of the invention

[0004] The invention provides a cleaning agent, which has the advantages of good stability, high dirt removal rate, low residual metal element content and low backwashing rate.

[0005] The invention also provides a method for preparing the cleaning agent, which has simple process and is convenient for industrial production.

[0006] The present invention also provides a method for cleaning a silicon wafer material, which can reduce damage to the surface of the silicon wafer material while removing pollutants on the surface of the silicon wafer material, thereby improving the cleaning efficiency of the silicon wafer material.

[0007] In a first aspect, the present invention provides a cleaning agent, comprising: alkyl glycoside, iminodisuccinic acid, an inorganic base and water.

[0008] The cleaning agent as described above, wherein the alkyl chain length of the alkyl glycoside is C8-C14.

[0009] The cleaning agent as described above, wherein the mass percentage of alkyl glycoside in the cleaning agent is 20%-30%; and / or,

[0010] The mass percentage of iminodisuccinic acid in the cleaning agent is 0.1%-0.3%; and / or,

[0011] The mass percentage of the inorganic alkali in the cleaning agent is 1%-3%; and / or,

[0012] The balance in the cleaning agent is water.

[0013] The cleaning agent as described above, wherein the inorganic alkali comprises sodium hydroxide and / or potassium hydroxide.

[0014] The cleaning agent as described above, wherein the cleaning agent further comprises: a foaming agent and / or a dispersant.

[0015] The cleaning agent as described above, wherein the foaming agent comprises at least one of sodium methyl laurate sulfonate, sodium coconut sulfate, sodium tridecyl alcohol polyether sulfate, and sodium lauryl sulfoacetate; and / or,

[0016] The dispersant includes at least one of sodium metasilicate pentahydrate, sodium citrate and sodium polyacrylate.

[0017] The cleaning agent as described above, wherein the mass percentage of the foaming agent in the cleaning agent is 1.8%-6.8%; and / or,

[0018] The mass percentage of the dispersant in the cleaning agent is 1%-6%.

[0019] In a second aspect, the present invention provides a method for preparing the above-mentioned cleaning agent, comprising the following steps: mixing alkyl glycoside, iminodisuccinic acid, an inorganic base and water to obtain the cleaning agent.

[0020] In a third aspect, the present invention provides a method for cleaning silicon wafer materials, the cleaning method comprising the following steps: using the cleaning agent described in the first aspect to clean the silicon wafer material to obtain the cleaned silicon wafer material.

[0021] The cleaning method as described above comprises: mixing the cleaning agent and water in a mass ratio of 1:(1-10), adding the silicon wafer material to be cleaned therein, and then ultrasonically cleaning the silicon wafer material to be cleaned at 45-55°C.

[0022] The cleaning agent of the present invention has the advantages of good stability, high decontamination rate, low residual metal element content and low backwashing rate. The cleaning agent can reduce the damage to the surface of the silicon wafer while removing pollutants on the surface of the silicon wafer material, thereby improving the cleaning efficiency of the silicon wafer material. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are 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.

[0024] In a first aspect, the present invention provides a cleaning agent comprising: an alkyl glycoside, iminodisuccinic acid, an inorganic base and water.

[0025] The cleaning agent has the advantages of good stability (can be prepared in advance, saving cleaning cycles), high decontamination rate, low residual metal element content, and low backwash rate. Among them, alkyl polyglycoside is a non-ionic surfactant that can reduce the surface tension of water, so that the cleaning agent can be more evenly covered on the surface of the silicon wafer material, which helps the cleaning agent to contact and remove pollutants more comprehensively. In addition, the non-ionic properties of alkyl polyglycoside make it less corrosive to the silicon wafer material, and it can effectively remove pollutants on the surface of the silicon wafer without causing excessive corrosion or damage to the surface of the silicon wafer. Iminodisuccinic acid is a chelating agent that can form a stable complex with metal ions, thereby effectively removing metal ions on the surface of the silicon wafer material and preventing metal ions from depositing on the surface of the silicon wafer material. Inorganic alkali (such as potassium hydroxide and sodium hydroxide) helps to strip impurities from the surface of the silicon material by providing an alkaline environment and generating anionic products, and does not generate new pollutants, which can significantly improve the decontamination ability of the cleaning agent. Water, as a dispersion medium, can fully dissolve and disperse alkyl polyglycoside, iminodisuccinic acid and inorganic alkali, so that the cleaning agent has a better cleaning effect.

[0026] It is worth mentioning that the cleaning agent of the present invention is an alkaline water-based environmentally friendly cleaning agent, which can achieve low cost, no harm and no pollution.

[0027] In some embodiments, the alkyl chain length of the alkyl glycoside is C8-C14. The length of the alkyl chain affects the surface activity and solubility of the alkyl glycoside. When the alkyl chain length of the alkyl glycoside is C8-C14, the alkyl glycoside has a better surface activity, so that the cleaning agent has a better decontamination ability. The present invention screens the contents of the alkyl glycoside, iminodisuccinic acid, inorganic base and water in the cleaning agent, so that the cleaning agent has a better room temperature stability and decontamination efficiency. In some embodiments, the mass percentage of the alkyl glycoside in the cleaning agent is 20%-30%, for example, it can be 20%, 22%, 24%, 26%, 28% or 30%, etc., preferably 26%-30%.

[0028] The mass percentage of iminodisuccinic acid in the cleaning agent is 0.1%-0.3%, for example, it can be 0.1%, 0.15%, 0.2%, 0.25% or 0.3%.

[0029] The mass percentage of the inorganic alkali in the cleaning agent is 1%-3%, for example, it can be 1%, 1.5%, 2%, 2.5% or 3%.

[0030] The balance in the cleaning agent is water.

[0031] In some embodiments, the inorganic base includes sodium hydroxide and / or potassium hydroxide, which can better dissolve and remove the oxide layer and particulate contaminants on the surface of the silicon wafer, further improving the surface cleanliness of the silicon wafer.

[0032] In some embodiments, the cleaning agent further includes: a foaming agent and / or a dispersant. The main function of the foaming agent is to promote the formation of foam, increase the surface area of ​​the cleaning agent, thereby enhancing the contact with the pollutants and improving the cleaning agent's decontamination efficiency. At the same time, the foam can form a buffer layer on the surface of the silicon wafer material, which helps to reduce the friction damage to the surface of the silicon wafer material during the cleaning process. The dispersant can effectively disperse the pollutants and prevent them from re-depositing on the surface of the silicon wafer material after cleaning, ensuring the durability of the cleaning effect and improving the decontamination ability of the cleaning agent.

[0033] In some embodiments, the foaming agent includes at least one of sodium methyl laurate sulfonate, sodium coconut sulfate, sodium tridecyl alcohol polyether sulfate, and sodium lauryl sulfoacetate. The above foaming agent can produce rich and stable foam, further increase the surface area of ​​the cleaning agent, and improve the contact efficiency between the cleaning agent and the pollutants.

[0034] The dispersant includes at least one of sodium metasilicate pentahydrate, sodium citrate, and sodium polyacrylate. The dispersant can better disperse pollutants and further improve the decontamination ability of the cleaning agent.

[0035] It can be understood that by selecting the content of foaming agent and dispersant in the cleaning agent, the dirt removal ability of the cleaning agent can be further improved. In some embodiments, the mass percentage of the foaming agent in the cleaning agent is 1.8%-6.8%, for example, it can be 1.8%, 2.8%, 3.8%, 4.8%, 5.8% or 6.8%, etc., preferably 1.8%-3.8%, and the mass percentage of the dispersant in the cleaning agent is 1%-6%, for example, it can be 1%, 2%, 3%, 4%, 5% or 6%, etc., preferably 1%-3%.

[0036] In a second aspect, the present invention provides a method for preparing the above-mentioned cleaning agent, comprising the following steps: mixing alkyl glycoside, iminodisuccinic acid, an inorganic base and water to obtain the cleaning agent.

[0037] The preparation method of the cleaning agent of the invention has simple process and is convenient for industrial production.

[0038] In a third aspect, the present invention provides a method for cleaning silicon wafer materials, the cleaning method comprising the following steps: using the cleaning agent described in the first aspect to clean the silicon wafer material to obtain the cleaned silicon wafer material.

[0039] The silicon wafer material of the present invention can be silicon scraps, which refer to scraps or waste generated during the silicon wafer manufacturing process. The silicon scraps can be re-purified through a recycling process after cleaning and used to produce new silicon wafers. The present invention does not limit the shape and size of the silicon wafer material.

[0040] The present invention uses the above cleaning agent to clean the silicon wafer material to be cleaned, which can remove pollutants on the surface of the silicon wafer material while reducing damage to the surface of the silicon wafer material, thereby improving the cleaning efficiency of the silicon wafer material and reducing the defect rate of the silicon wafer material.

[0041] In the present invention, the cleaning process comprises: mixing a cleaning agent and water in a mass ratio of 1:(1-10), adding the silicon wafer material to be cleaned therein, and then ultrasonically cleaning the silicon wafer material to be cleaned at 45-55°C.

[0042] Illustratively, during the cleaning process, the mass ratio of the cleaning agent to water can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, etc.

[0043] Specifically, the cleaning process of the present invention includes: firstly, the cleaning agent and water are mixed in a mass ratio of 1: (1-10), and the mass ratio of the cleaning agent to water can be adjusted according to the degree of dirtiness of the silicon wafer material or the cleaning requirements, which is helpful to effectively remove pollutants on the surface of the silicon wafer material while saving the amount of cleaning agent, and reduce damage to the surface of the silicon wafer material. Subsequently, the mixed solution of the cleaning agent and water is heated to 45-55°C for ultrasonic cleaning. Heating the mixed solution of the cleaning agent and water to 45-55°C helps to improve the activity and decontamination ability of the cleaning agent, while avoiding potential damage to the silicon wafer material due to excessively high temperature; ultrasonic cleaning is conducive to more efficient removal of pollutants on the surface of the silicon wafer material by generating high-frequency vibrations in the cleaning agent.

[0044] In some embodiments, the cleaning method comprises the following steps:

[0045] 1) Mechanically wiping the silicon wafer material to be cleaned with a brush or a wiping cloth helps to level the surface of the silicon wafer material, and then immersing the mechanically wiped silicon wafer material in a water tank to remove floating dust on the surface of the silicon wafer material;

[0046] 2) mixing the cleaning agent described in the first aspect with water in a mass ratio of 1:(1-10), adding the silicon wafer material to be cleaned thereto, and then ultrasonically cleaning the silicon wafer material to be cleaned at 45-55° C. for 5-10 minutes;

[0047] 3) Transfer the silicon wafer material after ultrasonic cleaning to a water tank at 15-30°C for ultrasonic rinsing for 5 minutes, and the number of ultrasonic rinsing is 2 times;

[0048] 4) Finally, the silicon wafer material after ultrasonic rinsing is dried at 25° C. for 15-20 minutes to obtain a cleaned silicon wafer material.

[0049] Hereinafter, the present invention will be further described in detail through specific examples.

[0050] The cleaning agents in Examples 1-6 are prepared by a method comprising the following steps:

[0051] Alkyl polyglycoside (APG0814), iminodisuccinic acid, inorganic base, foaming agent, dispersant and water were mixed at 50° C. to obtain a cleaning agent. The type and mass percentage of each component in the cleaning agent in Examples 1-6 are shown in Table 1.

[0052] Table 1

[0053] Mass percentage (%) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Alkyl glycoside 20 22 24 26 28 30 Iminodisuccinic acid 0.3 0.2 0.2 0.1 0.2 0.2 Sodium methyl laurate sulfonate 6.8 5.8 4.8 3.8 2.8 1.8 Sodium Metasilicate Pentahydrate 6 5 4 3 2 1 Potassium hydroxide 2 1 2 2 2 3 water margin margin margin margin margin margin

[0054] Comparative Example 1

[0055] The preparation method of the cleaning agent in this comparative example is basically the same as that in Example 1, except that an equal amount of alkyl glycoside is replaced by sodium dodecyl sulfate.

[0056] Comparative Example 2

[0057] The preparation method of the cleaning agent in this comparative example is basically the same as that in Example 1, except that an equal amount of iminodisuccinic acid is replaced by citric acid.

[0058] Preparation example:

[0059] 1) Mechanically wipe the silicon wafer material to be cleaned with a brush, and then immerse the mechanically wiped silicon wafer material in a water tank;

[0060] 2) After the cleaning agents prepared in Examples 1-6 and Comparative Examples 1-2 were mixed with water at a mass ratio of 1:10, the silicon wafer material to be cleaned was added thereto, and then the silicon wafer material to be cleaned was ultrasonically cleaned at 50° C. for 5 minutes;

[0061] 3) Transfer the silicon wafer material after ultrasonic cleaning to a water tank for ultrasonic rinsing at 30° C. for 5 minutes, and ultrasonic rinsing twice;

[0062] 4) Finally, the silicon wafer material after ultrasonic rinsing is dried at 25° C. for 20 minutes to obtain a cleaned silicon wafer material.

[0063] Performance Testing:

[0064] (1) Stability: The cleaning agents in the examples and comparative examples were allowed to stand at 20° C. for 24 h and observed by naked eyes to see whether the cleaning agents were stratified. If stratification occurred, it indicated that the cleaning agents had poor stability. If no stratification occurred, it indicated that the cleaning agents had excellent stability. The results are shown in Table 2.

[0065] (2) Decontamination rate: The silicon wafer material sample before cleaning is collected using the test instrument ICP-OES. The pollutant content in the silicon wafer material sample is measured to obtain the initial concentration C of the pollutant. initial After cleaning with the cleaning agents of the embodiment and the comparative example, the cleaned silicon material samples were collected, and the pollutant content in the samples was determined using the same analytical method to obtain the final concentration C of the pollutants. final Finally, the decontamination rate is calculated according to the following formula:

[0066] The results are shown in Table 2.

[0067] (3) Residual metal element content: The cleaning agents in the embodiments and comparative examples were used to clean silicon wafer material samples, and the metal mass spectra of the same silicon wafer material samples after digestion before and after cleaning were tested. The content was calculated to obtain the residual metal element content. The types of metal elements include iron, chromium, nickel, copper, zinc, and sodium. The results are shown in Table 2.

[0068] (4) Rewashing rate: The cleaning agents in the examples and comparative examples were used to clean silicon wafer material samples, and the ratio of the number of silicon wafer materials that needed to be rewashed to the total number of cleaned silicon wafer materials was determined. During the cleaning process of silicon wafer materials, some silicon wafer materials needed to be cleaned twice or more because of incomplete cleaning. The cleaning status of the silicon wafer materials was mainly observed by naked eyes, or the turbidity test results of the final rinse solution were measured. The results are shown in Table 2.

[0069] Table 2

[0070]

[0071] From the analysis of Table 2, it can be seen that compared with Comparative Examples 1-2, the cleaning agents in Examples 1-6 of the present invention have the advantages of good stability, high dirt removal rate, low residual metal element content and low backwash rate.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cleaning agent, characterized in that: The cleaning agent comprises: alkyl glycoside, iminodisuccinic acid, inorganic alkali and water.

2. The cleaning agent according to claim 1, characterized in that The alkyl chain length of the alkyl glycoside is C8-C14.

3. The cleaning agent according to claim 1, characterized in that The mass percentage of alkyl glycoside in the cleaning agent is 20%-30%; and / or, The mass percentage of iminodisuccinic acid in the cleaning agent is 0.1%-0.3%; and / or, The mass percentage of the inorganic alkali in the cleaning agent is 1%-3%; and / or, The balance in the cleaning agent is water.

4. The cleaning agent according to any one of claims 1 to 3, characterized in that The inorganic base includes sodium hydroxide and / or potassium hydroxide.

5. The cleaning agent according to any one of claims 1 to 4, characterized in that The cleaning agent also includes: a foaming agent and / or a dispersant.

6. The cleaning agent according to claim 5, characterized in that The foaming agent includes at least one of sodium methyl laurate sulfonate, sodium coconut sulfate, sodium tridecyl alcohol polyether sulfate, and sodium lauryl sulfoacetate; and / or, The dispersant includes at least one of sodium metasilicate pentahydrate, sodium citrate and sodium polyacrylate.

7. The cleaning agent according to claim 5 or 6, characterized in that: The mass percentage of the foaming agent in the cleaning agent is 1.8%-6.8%; and / or, The mass percentage of the dispersant in the cleaning agent is 1%-6%.

8. A method for preparing the cleaning agent according to any one of claims 1 to 7, characterized in that: The following steps are involved: The cleaning agent is obtained by mixing alkyl glycoside, iminodisuccinic acid, an inorganic base and water.

9. A method for cleaning silicon wafer material, characterized in that: The cleaning method comprises the following steps: using the cleaning agent according to any one of claims 1 to 7 to clean the silicon wafer material to obtain the cleaned silicon wafer material.

10. The cleaning method according to claim 9, characterized in that: The cleaning process comprises: mixing the cleaning agent and water in a mass ratio of 1:(1-10), adding the silicon wafer material to be cleaned therein, and then ultrasonically cleaning the silicon wafer material to be cleaned at 45-55°C.

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