Silicon material cleaning agent composition and silicon material cleaning method

Abstract

The invention provides a silicon material cleaning agent composition and a silicon material cleaning method, and relates to the technical field of photovoltaics. The silicon material cleaning agent composition comprises a first cleaning agent, a second cleaning agent and a third cleaning agent, based on 100 parts by weight of the first cleaning agent, the first cleaning agent comprises the following components in parts by weight: 5-15 parts of a first nonionic surfactant, 0.05-0.15 part of a defoaming agent and the balance of pure water; based on 100 parts by weight of the second cleaning agent, the second cleaning agent comprises the following components in parts by weight: 1-3 parts of a second nonionic surfactant, 5-15 parts of hydrofluoric acid and the balance of pure water; based on 100 parts by weight of the third cleaning agent, the third cleaning agent comprises the following components in parts by weight: 1-3 parts of diethylenetriaminepenta (methylene phosphonic acid), 1-3 parts of 1-hydroxyethylidene-1, 1-diphosphonic acid and the balance of pure water. The silicon material cleaning agent composition is environmentally friendly, stable, good in silicon material cleaning effect and small in damage to the surface of a silicon material.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a silicon material cleaning agent composition and a silicon material cleaning method. Background Art

[0002] The statements in this section merely provide background art related to the present invention and do not necessarily constitute prior art.

[0003] In the photovoltaic field, silicon materials are usually cleaned with a mixture of hydrofluoric acid and nitric acid, but there is a problem of strong corrosiveness. Strict safety measures need to be taken during the operation to prevent harm to operators and equipment. At the same time, the cost of waste liquid treatment is also high. Organic acids (such as citric acid, formic acid, etc.) are used to replace hydrofluoric acid and nitric acid to reduce corrosiveness, but the cleaning effect is poor, for example, it is difficult to remove the oxide layer of silicon materials. Summary of the invention

[0004] The object of the present invention is to provide a silicon material cleaning agent composition and a silicon material cleaning method to solve the technical problem that the cleaning operation is complicated due to the strong corrosiveness of the existing silicon material cleaning agents.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a silicon material cleaning agent composition, comprising: a first cleaning agent, a second cleaning agent and a third cleaning agent;

[0007] Based on 100 parts by weight of the first cleaning agent, the first cleaning agent includes the following components by weight:

[0008] 5 to 15 parts of the first nonionic surfactant,

[0009] Defoaming agent 0.05 to 0.15 parts,

[0010] The balance is pure water;

[0011] The first nonionic surfactant includes at least two of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyoxyethylene alkylamine, polyoxyethylene alkylolamide, fatty acid diethanolamide, and lauroyl diethanolamine;

[0012] Based on 100 parts by weight of the second cleaning agent, the second cleaning agent includes the following components by weight:

[0013] 1 to 3 parts of the second nonionic surfactant,

[0014] 5 to 15 parts of hydrofluoric acid,

[0015] The balance is pure water;

[0016] The second nonionic surfactant includes at least one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyoxyethylene alkylamine, polyoxyethylene alkylolamide, fatty acid diethanolamide, and lauroyl diethanolamine;

[0017] Based on 100 parts by weight of the third cleaning agent, the third cleaning agent includes the following components by weight:

[0018] 1 to 3 parts of diethylenetriaminepenta(methylenephosphonic acid),

[0019] Hydroxyethylidene diphosphonic acid, 1 to 3 parts,

[0020] The balance is pure water.

[0021] According to at least one embodiment of the present invention, based on 100 parts by weight of the first cleaning agent, the first nonionic surfactant includes the following components in parts by weight:

[0022] 2 to 6 parts of fatty alcohol polyoxyethylene ether,

[0023] 2 to 6 parts of alkylphenol polyoxyethylene ether,

[0024] 1 to 3 parts of fatty acid diethanolamide.

[0025] According to at least one embodiment of the present invention, based on 100 parts by weight of the first cleaning agent, the first nonionic surfactant includes the following components in parts by weight:

[0026] 3 to 5 parts of fatty alcohol polyoxyethylene ether,

[0027] 3 to 5 parts of alkylphenol polyoxyethylene ether,

[0028] 1.5 to 2.5 parts of fatty acid diethanolamide.

[0029] According to at least one embodiment of the present invention, the second nonionic surfactant includes one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether and fatty acid diethanolamide.

[0030] According to at least one embodiment of the present invention, based on 100 parts by weight of the second cleaning agent, the second cleaning agent includes the following components in parts by weight:

[0031] 1.5 to 2 parts of the second nonionic surfactant,

[0032] 8 to 12 parts of hydrofluoric acid,

[0033] The balance is pure water.

[0034] According to at least one embodiment of the present invention, based on 100 parts by weight of the third cleaning agent, the third cleaning agent includes the following components in parts by weight:

[0035] 1.5 to 2.5 parts of diethylenetriamine penta (methylene phosphonic acid),

[0036] 1.5 to 2.5 parts of hydroxyethylidene diphosphonic acid,

[0037] The balance is pure water.

[0038] In a second aspect, the present invention further provides a silicon material cleaning method, using the silicon material cleaning agent composition described in the first aspect, the method comprising:

[0039] The silicon material is completely immersed in the first cleaning agent, the second cleaning agent and the third cleaning agent in sequence for cleaning.

[0040] According to at least one embodiment of the present invention, the method further comprises:

[0041] An ultrasonic cleaning step before the silicon material is completely immersed in the second cleaning agent for cleaning;

[0042] The step of ultrasonic cleaning before the silicon material is completely immersed in the third cleaning agent for cleaning;

[0043] The silicon material is completely immersed in the third cleaning agent for cleaning and then an ultrasonic cleaning step is performed.

[0044] According to at least one embodiment of the present invention, before the silicon material is completely immersed in the first cleaning agent for cleaning, the method further includes:

[0045] After removing dust and impurities on the surface of the silicon material, the silicon material is ultrasonically cleaned.

[0046] According to at least one embodiment of the present invention, after the silicon material is completely immersed in the third cleaning agent for cleaning, the method further includes:

[0047] The silicon material is dried at a temperature of 80°C to 100°C.

[0048] Among the one or more technical solutions provided in the exemplary embodiments of the present invention, at least one of the following beneficial effects can be achieved.

[0049] In the silicon material cleaning agent composition of the exemplary embodiment of the present invention, three non-ionic surfactants are used in the first cleaning agent for compounding. On the one hand, since the non-ionic surfactant is uncharged, it can remove metal ions more thoroughly than the anionic surfactant that may form a complex with the metal ions on the surface of the silicon material; the non-ionic surfactant has better spreadability and wettability on the silicon material surface than the anionic surfactant, which helps to clean the silicon material surface more evenly and reduce the surface roughness; compared with the anionic surfactant, the non-ionic surfactant has lower foaming property and is not easy to affect the contact between the cleaning liquid and the silicon material surface, thereby improving the cleaning efficiency; the non-ionic surfactant has better biodegradability and is more environmentally friendly; on the other hand, the first cleaning agent composed of the three non-ionic surfactants produces a synergistic effect in the cleaning process of the silicon material, which can improve the wettability and dispersibility of the cleaning agent, increase the contact area with the silicon material surface, and improve the cleaning efficiency; moreover, the compounding of the three non-ionic surfactants can further reduce the surface tension of the first cleaning agent, which helps the cleaning agent to penetrate into the microstructure of the silicon material and more thoroughly remove the pollutants therein.

[0050] Furthermore, the second cleaning agent uses a non-ionic surfactant in combination with hydrofluoric acid for cleaning. Compared with ionic surfactants, the chemical properties are more stable and less likely to react with hydrofluoric acid, which helps to maintain the stability and effectiveness of the cleaning agent. In comparison, anionic surfactants produce more foam, which may affect the contact between the cleaning agent and the silicon material surface and reduce the cleaning efficiency. In some cases, cationic surfactants may also damage the silicon material surface and affect the electrical properties of the silicon material; and cationic surfactants may produce a strong adsorption effect with the negatively charged oxide layer on the surface of the silicon material, resulting in incomplete cleaning.

[0051] Based on this, the silicon material cleaning agent composition of the exemplary embodiment of the present invention uses a compounded nonionic surfactant and a compounded chelating agent to replace the nitric acid in the prior art, which reduces the corrosion of the silicon material, prolongs the service life of the silicon material, and combines with hydrofluoric acid to clean the oxide layer on the silicon material, which can achieve a good cleaning effect. The silicon material cleaning agent composition has reduced corrosiveness and is safer for operators. Through the ratio of each component and mutual coordination, impurities on the surface of the silicon material are removed in a targeted manner, which is more efficient and less costly. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings illustrate exemplary embodiments of the present invention and together with the description serve to explain the principles of the present invention, and these drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification;

[0053] Figure 1It is a schematic flow chart of a silicon material cleaning method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0054] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0055] In the photovoltaic industry, silicon is a key material for manufacturing semi-solar cells. Silicon materials need to go through multiple steps in the production process, including cutting, grinding, corrosion, etc. These steps may leave various impurities on the surface of silicon materials. The surface impurities of silicon materials will affect the quality of silicon materials and the performance of photovoltaic cells. During the processing of silicon materials, its surface will be exposed to many impurities, mainly of four types.

[0056] For example, metal impurities (iron, copper, aluminum, etc.) seriously affect the electrical properties of silicon materials; organic impurities, including various organic residues, may have adverse effects in subsequent processes; the oxide layer, the oxide layer on the surface of the silicon material may affect the purity and electrical properties of the silicon material; particulate matter, including silicon dust and other tiny particles, may cause defects in the silicon rod production process.

[0057] The commonly used silicon material cleaning agent is a mixed acid of hydrofluoric acid and nitric acid. This type of cleaning agent is highly corrosive to the surface of the silicon material, which may cause damage to the surface structure of the silicon material and affect the performance of the produced devices. Strict safety measures need to be taken during the cleaning operation, the process complexity is increased, and the harm to personnel and equipment is also greater. The waste liquid treatment cost generated after cleaning the silicon material is high, which does not conform to the current development trend of green environmental protection.

[0058] In the related art, organic acid is used instead of hydrofluoric acid and nitric acid to reduce the corrosiveness, but it is difficult to completely remove the oxide layer on the surface of the silicon material and the cleaning effect is poor.

[0059] In response to the above problems, in the silicon material cleaning agent composition of the exemplary embodiment of the present invention, non-ionic surfactants are used to compound the impurities on the surface of the silicon material, non-ionic surfactants are compounded with hydrofluoric acid, and chelating agents are compounded, and cleaning is performed in steps to reduce the amount of foam, which can improve the cleaning effect while reducing water loss.

[0060] The silicon material cleaning agent composition of the exemplary embodiment of the present invention can be designed to clean the silicon material in a targeted manner, mainly considering the following factors:

[0061] (1) The cleaning agent can complex or dissolve metal ions to remove metal contamination on the surface;

[0062] (2) Ability to remove organic residues such as grease, resin, wax, etc. on the surface of silicon materials;

[0063] (3) Certain components in the cleaning agent, such as acidic substances, can react with the oxide layer on the surface of the silicon material;

[0064] (4) The cleaning agent should be able to suspend and disperse silica dust and other tiny particles.

[0065] In some embodiments, the silicon material cleaning agent composition of the exemplary embodiment of the present invention includes a first cleaning agent, a second cleaning agent and a third cleaning agent. Based on 100 parts by weight of the first cleaning agent, the first cleaning agent includes the following components by weight: 5 to 15 parts of a first nonionic surfactant, 0.05 to 0.15 parts of a defoaming agent, and the balance is pure water. Specifically, the first nonionic surfactant includes two or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyoxyethylene alkylamine, polyoxyethylene alkylolamide, fatty acid diethanolamide, lauryl diethanolamine, etc.

[0066] Exemplarily, the formula of the first nonionic surfactant consists of three surfactants, for example, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether and fatty acid diethanolamide.

[0067] The specific component contents (parts by weight) include 2 to 6 parts of fatty alcohol polyoxyethylene ether, 2 to 6 parts of alkylphenol polyoxyethylene ether, and 1 to 3 parts of fatty acid diethanolamide; illustratively, 3 to 5 parts of fatty alcohol polyoxyethylene ether, 3 to 5 parts of alkylphenol polyoxyethylene ether, and 1.5 to 2.5 parts of fatty acid diethanolamide.

[0068] By compounding the above three non-ionic surfactants, the problem of excessive foam of anionic surfactants can be avoided, which affects the contact between the cleaning agent and the silicon material surface and reduces the cleaning efficiency; it can also avoid the problem that cationic surfactants may produce strong adsorption with the negatively charged oxide layer on the silicon material surface, resulting in incomplete cleaning.

[0069] Therefore, the following aspects need to be noted when selecting surfactants: the use of surfactants leads to excessive foam, increases the complexity of the operation or affects the cleaning quality; on the other hand, the appropriate ingredients and ratios should be selected according to the characteristics of impurities on the surface of the silicon material to achieve better cleaning effects.

[0070] For example, a defoaming agent is further added to the first cleaning agent. Based on 100 parts by weight of the first cleaning agent, the defoaming agent is 0.05 to 0.15 parts, optionally 0.07 to 0.13 parts, optionally 0.09 to 0.11 parts, and optionally 0.1 parts.

[0071] Exemplarily, the first cleaning agent is composed of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid diethanolamide, defoamer and pure water. The defoamer is a PPE type defoamer. By introducing a certain component of defoamer into the first cleaning agent, the foam generated by the cleaning agent is further reduced on the basis of the foam reduced by the compounding of the three non-ionic surfactants, thereby simplifying the operation process and improving the cleaning effect.

[0072] In some embodiments, based on 100 parts by weight of the second cleaning agent, the second cleaning agent includes the following components in parts by weight: 1 to 3 parts of a second non-ionic surfactant, 5 to 15 parts of hydrofluoric acid, and the remainder is pure water; wherein the second non-ionic surfactant includes at least one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyoxyethylene alkylamine, polyoxyethylene alkylolamide, fatty acid diethanolamide, and lauroyl diethanolamine.

[0073] Illustratively, the second nonionic surfactant may be one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether and fatty acid diethanolamide, more specifically fatty alcohol polyoxyethylene ether.

[0074] Exemplarily, based on 100 parts by weight of the second cleaning agent, the second cleaning agent includes the following components in parts by weight: 1.5 to 2 parts of fatty alcohol polyoxyethylene ether, 8 to 12 parts of hydrofluoric acid, and the remainder is pure water.

[0075] Exemplarily, the second cleaning agent consists of fatty alcohol polyoxyethylene ether, hydrofluoric acid and pure water.

[0076] When the nonionic surfactant introduced in the second cleaning agent is mixed with hydrofluoric acid, since the nonionic surfactant does not contain an electric charge, it avoids reacting with the ions in the hydrofluoric acid, reducing foam and precipitation, while ionic surfactants may cause these problems due to charge interaction. Therefore, by compounding a certain component of fatty alcohol polyoxyethylene ether with hydrofluoric acid and using the nonionic surfactant in the first cleaning agent, a more stable, safer and environmentally friendly cleaning agent is provided.

[0077] In some embodiments, based on 100 parts by weight of the third cleaning agent, the third cleaning agent includes the following components by weight: 1 to 3 parts of diethylenetriaminepenta(methylenephosphonic acid), 1 to 3 parts of hydroxyethylidenediphosphonic acid, and the remainder is pure water.

[0078] Exemplarily, the third cleaning agent consists of diethylenetriaminepenta(methylenephosphonic acid), hydroxyethylidenediphosphonic acid and pure water.

[0079] Exemplarily, based on 100 parts by weight of the third cleaning agent, the third cleaning agent includes the following components by weight: 1.5 to 2.5 parts of diethylenetriaminepenta(methylenephosphonic acid), 1.5 to 2.5 parts of hydroxyethylidenediphosphonic acid, and the remainder is pure water.

[0080] The compounding of the two chelating agents in the third cleaning agent within the above weight range can effectively remove the metal ions on the surface of the silicon material and protect the electrical properties of the silicon material.

[0081] Figure 1 Schematic diagram of the silicon material cleaning method according to an embodiment of the present invention. Figure 1 As shown, an exemplary embodiment of the present invention further provides a silicon material cleaning method, using the silicon material cleaning agent composition in the above embodiment, the silicon material cleaning method may include the following steps:

[0082] Step S101: completely immerse the silicon material in a first cleaning agent for cleaning.

[0083] Exemplarily, before step S101, the cleaning method further includes pre-cleaning: after removing dust and impurities on the surface of the silicon material, the silicon material is ultrasonically cleaned.

[0084] Specifically, in the initial stage of silicon material processing, surface pre-cleaning is a crucial step. First, use a soft brush that will not scratch the silicon wafer to gently brush the silicon material surface to effectively remove various dust and impurities attached to the silicon wafer.

[0085] Next, to further improve cleanliness, the silicon material will be placed in an ultrasonic cleaning machine for cleaning.

[0086] Ultrasonic cleaning is a powerful cleaning method that uses tiny bubbles (cavitation effect) generated by high-frequency sound waves. These bubbles form and burst quickly under the action of powerful sound waves, and the resulting impact force can effectively destroy residual impurities on the surface of the silicon wafer and in the micro-cracks. Ultrasonic cleaning is not only efficient, but also has a uniform cleaning effect, which can ensure that the surface of the silicon material is completely clean.

[0087] In the first cleaning tank, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid diethanolamide, PPE type defoamer and pure water are mixed together in a certain proportion. The silicon material is completely immersed in the first cleaning agent for soaking cleaning.

[0088] In step S101, particulate matter and organic matter are mainly removed. Although fatty alcohol polyoxyethylene ether has low foaming properties, other surfactants have strong foaming properties. Adding a PPE type defoamer can reduce the generation of foam.

[0089] Finally, the silicon material that has been immersed and cleaned in the first cleaning agent is ultrasonically cleaned in pure water to remove the first cleaning agent remaining on the surface.

[0090] Step S102: completely immerse the silicon material in a second cleaning agent for cleaning.

[0091] In the second cleaning tank, fatty alcohol polyoxyethylene ether, hydrofluoric acid and pure water are mixed together in a certain proportion, and the silicon material is completely immersed in the second cleaning agent for soaking cleaning.

[0092] In step S102, hydrofluoric acid mainly removes the oxide layer on the silicon material, and can also remove metal ions attached to the oxide layer. However, using hydrofluoric acid alone cannot avoid the re-adsorption of metal ions such as copper. Adding a low-foaming, acid- and alkali-resistant non-ionic surfactant fatty alcohol polyoxyethylene ether can avoid the re-adsorption of metal ions such as copper.

[0093] Finally, the silicon material that has been immersed and cleaned in the second cleaning agent is ultrasonically cleaned in pure water to remove the second cleaning agent remaining on the surface.

[0094] Step S103: completely immerse the silicon material in a third cleaning agent for cleaning.

[0095] In the third cleaning tank, diethylene triamine penta methylene phosphonic acid, hydroxy ethylidene diphosphonic acid and pure water are mixed together in a certain proportion, and the silicon material is completely immersed in the third cleaning agent for soaking cleaning.

[0096] In step S103 , two chelating agents are used to mainly remove metal ions on the silicon material that are not removed by the hydrofluoric acid.

[0097] Finally, the silicon material that has been immersed and cleaned in the third cleaning agent is ultrasonically cleaned in pure water to remove the third cleaning agent remaining on the surface.

[0098] Exemplarily, after each cleaning, the corresponding cleaning agent in each cleaning tank should be replaced to ensure the cleaning effect.

[0099] In some embodiments, after the silicon material is completely immersed in the third cleaning agent for cleaning, that is, after step S103, the method further includes: drying the silicon material at a temperature of 80°C to 100°C.

[0100] Specifically, the silicon material with the third cleaning agent remaining on the surface removed enters a drainage process, and then the silicon material is placed in an oven and dried at a suitable temperature, such as 80° C. to 100° C., to ensure that the surface of the silicon material is dry.

[0101] The following examples and comparative examples are given to illustrate the technical effects of the preparation methods of the exemplary embodiments of the present invention. It should be noted that, if the specific conditions are not specified in the examples and comparative examples, the conventional conditions or the conditions recommended by the manufacturer are followed. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0102] Example 1

[0103] A silicon material cleaning agent composition, comprising: a first cleaning agent, a second cleaning agent and a third cleaning agent;

[0104] Based on 100 parts by weight of the first cleaning agent, the first cleaning agent includes the following components by weight:

[0105] 4 parts of fatty alcohol polyoxyethylene ether, 4 parts of alkylphenol polyoxyethylene ether, 2 parts of fatty acid diethanolamide, 0.1 parts of PPE type defoamer, and the balance is deionized water.

[0106] Based on 100 parts by weight of the second cleaning agent, the second cleaning agent includes the following components by weight:

[0107] 2 parts of fatty alcohol polyoxyethylene ether, 10 parts of hydrofluoric acid, and the balance is deionized water.

[0108] Based on 100 parts by weight of the third cleaning agent, the third cleaning agent includes the following components by weight:

[0109] 2 parts of diethylenetriamine penta (methylene phosphonic acid), 2 parts of hydroxyethylidene diphosphonic acid, and the balance is deionized water.

[0110] The silicon material cleaning method comprises the following steps:

[0111] Step 1: Use a soft brush that will not scratch the silicon material to gently scrub the surface of the silicon material to remove all kinds of dust and impurities attached to the silicon material;

[0112] Step 2: Place the silicon material in deionized water for ultrasonic cleaning;

[0113] Step 3: The silicon material is completely immersed in the first cleaning agent for cleaning, and then ultrasonically cleaned with deionized water;

[0114] Step 4: The silicon material is completely immersed in the second cleaning agent for cleaning, and then ultrasonically cleaned with deionized water;

[0115] Step 5: Immerse the silicon material completely in the third cleaning agent for cleaning, and then use deionized water for ultrasonic cleaning;

[0116] Step 6: After the silicon material is drained, it is placed in an oven at a drying temperature of 80°C to 100°C to dry the surface of the silicon material.

[0117] Example 2

[0118] The difference between this embodiment and embodiment 1 is only that:

[0119] The first cleaning agent includes 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of alkylphenol polyoxyethylene ether, and 1 part of fatty acid diethanolamide.

[0120] Example 3

[0121] The difference between this embodiment and embodiment 1 is only that:

[0122] The first cleaning agent includes 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of alkylphenol polyoxyethylene ether, and 1 part of fatty acid diethanolamide;

[0123] The second cleaning agent contains 1 part of fatty alcohol polyoxyethylene ether and 5 parts of hydrofluoric acid;

[0124] Example 4

[0125] The difference between this embodiment and embodiment 1 is only that:

[0126] The first cleaning agent includes 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of alkylphenol polyoxyethylene ether, and 1 part of fatty acid diethanolamide;

[0127] The second cleaning agent contains 1 part of fatty alcohol polyoxyethylene ether and 5 parts of hydrofluoric acid;

[0128] The third cleaning agent includes 1 part of diethylenetriamine penta (methylene phosphonic acid) and 1 part of hydroxyethylidene diphosphonic acid.

[0129] Example 5

[0130] The difference between this embodiment and embodiment 1 is only that:

[0131] The first cleaning agent includes 6 parts of fatty alcohol polyoxyethylene ether, 6 parts of alkylphenol polyoxyethylene ether and 3 parts of fatty acid diethanolamide.

[0132] Example 6

[0133] The difference between this embodiment and embodiment 1 is only that:

[0134] The first cleaning agent includes 6 parts of fatty alcohol polyoxyethylene ether, 6 parts of alkylphenol polyoxyethylene ether, and 3 parts of fatty acid diethanolamide;

[0135] The second cleaning agent contains 3 parts of fatty alcohol polyoxyethylene ether and 15 parts of hydrofluoric acid;

[0136] Example 7

[0137] The difference between this embodiment and embodiment 1 is only that:

[0138] The first cleaning agent includes 6 parts of fatty alcohol polyoxyethylene ether, 6 parts of alkylphenol polyoxyethylene ether, and 3 parts of fatty acid diethanolamide;

[0139] The second cleaning agent contains 3 parts of fatty alcohol polyoxyethylene ether and 15 parts of hydrofluoric acid;

[0140] The third cleaning agent contains 3 parts of diethylenetriamine penta (methylene phosphonic acid) and 3 parts of hydroxyethylidene diphosphonic acid.

[0141] Comparative Example 1

[0142] The difference between this comparative example and Example 1 is only that:

[0143] The first cleaning agent contains 10 parts of fatty alcohol polyoxyethylene ether and no alkylphenol polyoxyethylene ether and fatty acid diethanolamide.

[0144] Comparative Example 2

[0145] The difference between this comparative example and Example 1 is only that:

[0146] The first cleaning agent contains 10 parts of alkylphenol polyoxyethylene ether, and no fatty alcohol polyoxyethylene ether and fatty acid diethanolamide.

[0147] Comparative Example 3

[0148] The difference between this comparative example and Example 1 is only that:

[0149] The first cleaning agent contains 10 parts of fatty acid diethanolamide and no alkylphenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether.

[0150] Comparative Example 4

[0151] The difference between this comparative example and Example 1 is only that:

[0152] The first cleaning agent contains 4 parts of potassium perfluorooctanoate, 4 parts of alkylphenol polyoxyethylene ether and 2 parts of fatty acid diethanolamide, and no fatty alcohol polyoxyethylene ether;

[0153] The second cleaning agent contains 2 parts of potassium perfluorooctanoate, 10 parts of hydrofluoric acid, and no fatty alcohol polyoxyethylene ether.

[0154] Comparative Example 5

[0155] The difference between this comparative example and Example 1 is only that:

[0156] The first cleaning agent contains 4 parts of sodium dodecylbenzene sulfonate, 4 parts of alkylphenol polyoxyethylene ether and 2 parts of fatty acid diethanolamide, and no fatty alcohol polyoxyethylene ether;

[0157] The second cleaning agent contains 2 parts of sodium dodecylbenzene sulfonate, 10 parts of hydrofluoric acid, and fatty alcohol polyoxyethylene ether.

[0158] Comparative Example 6

[0159] The difference between this comparative example and Example 1 is only that:

[0160] The third cleaning agent contains 4 parts of diethylenetriaminepenta(methylenephosphonic acid) and no hydroxyethylidenediphosphonic acid.

[0161] Comparative Example 7

[0162] The difference between this comparative example and Example 1 is only that:

[0163] The third cleaning agent contains 4 parts of hydroxyethylidene diphosphonic acid and no diethylene triamine penta (methylene phosphonic acid).

[0164] Comparative Example 8

[0165] The difference between this comparative example and Example 1 is only that:

[0166] The third cleaning agent contains 2 parts of hydroxyethylidene diphosphonic acid, 2 parts of sodium perfluorooctanoate, and no diethylenetriamine penta (methylene phosphonic acid).

[0167] Comparative Example 9

[0168] The difference between this comparative example and Example 1 is only that:

[0169] In the silicon material cleaning method, step 3 and step 4 are exchanged, and the silicon material is first cleaned in the second cleaning agent and then cleaned in the first cleaning agent.

[0170] Comparative Example 10

[0171] The difference between this comparative example and Example 1 is only that:

[0172] The components of the first cleaning agent, the second cleaning agent and the third cleaning agent are mixed to prepare a cleaning agent mixed solution, and steps 3 to 5 are replaced by immersing the silicon material in the cleaning agent mixed solution for cleaning.

[0173] Comparative Example 11

[0174] The difference between this comparative example and Example 1 is only that:

[0175] The second cleaning agent contains 4 parts of fatty alcohol polyoxyethylene ether and 10 parts of hydrofluoric acid.

[0176] Comparative Example 12

[0177] The difference between this comparative example and Example 1 is only that:

[0178] The second cleaning agent contains 0.5 parts of fatty alcohol polyoxyethylene ether and 10 parts of hydrofluoric acid.

[0179] Comparative Example 13

[0180] The difference between this comparative example and Example 1 is only that:

[0181] The third cleaning agent contains 0.5 parts of diethylenetriaminepenta(methylenephosphonic acid) and 0.5 parts of hydroxyethylidenediphosphonic acid.

[0182] Comparative Example 14

[0183] The difference between this comparative example and Example 1 is only that:

[0184] The third cleaning agent contains 4 parts of diethylenetriaminepenta(methylenephosphonic acid) and 4 parts of hydroxyethylidenediphosphonic acid.

[0185]

Test method

[0186] The present invention tests the surface metal content, organic residue and cleaning efficiency of the silicon materials after cleaning in the above comparative examples and embodiments. The specific test results are shown in Table 1. The test standards are as follows:

[0187] Surface metal content: GB / T 29849-2013 Inductively coupled plasma mass spectrometry method for measuring surface metal impurity content of silicon materials for photovoltaic cells.

[0188] Residual organic matter: GB / T 24577-2009 Thermal desorption gas chromatography method for determination of organic pollutants on the surface of silicon wafers;

[0189] The cleaning efficiency intervals are classified as follows:

[0190] High: The total cleaning and drying time is within 15 minutes, the metal content on the silicon material surface is low, the amount of organic residue is small, and the cleaning effect is significant.

[0191] Medium-high: The total cleaning and drying time is 15-18 minutes. The metal content and organic residue on the surface of the silicon material are moderate, and the cleaning effect is good.

[0192] Medium: The total time for cleaning and drying is 18-21 minutes. The metal content and organic residue on the surface of the silicon material are slightly higher, and the cleaning effect is average.

[0193] Medium-low: The total cleaning and drying time is 21-24 minutes. The metal content and organic residue on the surface of the silicon material are high, and the cleaning effect is poor.

[0194] Low: The total cleaning and drying time exceeds 24 minutes, the metal content and organic residue on the surface of the silicon material are high, and the cleaning effect is poor.

[0195] Table 1 Cleaning effect of silicon materials in various embodiments and comparative examples

[0196]

[0197] According to the test results in Table 1, the cleaning methods for silicon materials in the exemplary embodiments of the present invention have higher cleaning efficiency, more thorough removal of metal ions, less organic residue, and less foam control, which reduces the complexity of operation. At the same time, the components of the cleaning agent used in the exemplary embodiments of the present invention have better biodegradability, are more environmentally friendly, and cause less damage to silicon materials than the use of nitric acid and hydrofluoric acid.

[0198] It can be seen from Comparative Examples 1 to 3 that only one of the three nonionic surfactants is used in the first cleaning agent, and the metal content and organic residue on the surface of the silicon material are both high. Based on this, the first cleaning agent composed of three nonionic surfactants is used in the exemplary embodiment of the present invention, and a synergistic effect is produced during the cleaning process. The three nonionic surfactants used in combination improve the wettability and dispersibility of the cleaning agent, increase its contact area with the surface of the silicon material, and improve the cleaning efficiency; at the same time, the combination of different surfactants may further reduce the surface tension of the cleaning agent, which helps the cleaning agent penetrate into the microstructure of the silicon material and remove impurities more thoroughly. It should be noted that the level of cleaning efficiency refers to the length of the cleaning time. Generally, the more foam the cleaning agent produces, the longer the cleaning time will be, and the lower the cleaning efficiency.

[0199] It can be seen from Comparative Example 4 that its ability to remove surface metal ions is only slightly higher than that of Example 4, the amount of organic residue is higher than that of each embodiment, and the cleaning efficiency is also lower than that of each embodiment. Based on this, although the potassium perfluorooctanoate in Comparative Example 4 can further reduce the surface tension of water, excessive foam affects the uniform distribution of the cleaning agent, thereby reducing the ability to remove metal ions and organic matter. At the same time, potassium perfluorooctanoate is difficult to degrade in the environment, and the complex synthesis requires precise chemical control, which increases costs. Compared with Comparative Example 4, the nonionic surfactant used in the exemplary embodiment of the present invention has better biodegradability, and the amount of foam produced is less, which has less effect on the uniform distribution of the cleaning solution, better cleaning effect, and simpler operation.

[0200] It can be seen from Comparative Example 5 that its surface metal content is higher than that of each embodiment, and the amount of organic residue is higher than that of each embodiment except Example 4, and the cleaning efficiency is at a low level. Sodium dodecylbenzene sulfonate, as an anionic surfactant, forms a complex with the metal ions on the surface of the silicon material, resulting in incomplete removal of the metal ions; and non-ionic surfactants avoid this interaction because they are not charged. At the same time, their spreadability and wettability on the surface of the silicon material are better than anionic surfactants, which helps to clean the surface of the silicon material more evenly and reduce surface roughness. Furthermore, anionic surfactants are prone to foaming, which may affect the contact between the cleaning agent and the surface of the silicon material and reduce the cleaning efficiency; while non-ionic surfactants have low foaming properties, which helps to improve the cleaning efficiency. Furthermore, anionic surfactants have poor degradability in the natural environment and may have a certain impact on the environment.

[0201] It can be seen from Comparative Examples 6 and 7 that their ability to remove metal ions on the surface of silicon materials is worse than that of each embodiment, and the amount of residual organic matter is higher than that of the other embodiments except Embodiment 3 and Embodiment 4. It can be seen that the use of two chelating agents produces a synergistic effect in the cleaning process, and the metal ions can be removed more effectively by acting on the surface of silicon materials through different mechanisms.

[0202] It can be seen from Comparative Example 8 that the surface metal content after cleaning is much greater than that of each embodiment, the residual organic matter is higher than that of the other embodiments except Embodiment 3 and Embodiment 4, and the cleaning efficiency is lower than or the same as that of each embodiment. It can be seen that the use of chelating agent in combination with sodium perfluorooctanoate is difficult to completely remove the surface metal ions. At the same time, the poor degradability of perfluoro compounds may also have a certain impact on the environment.

[0203] It can be seen from Comparative Example 9 that its ability to remove metal ions and organic matter on the surface of the silicon material and its cleaning efficiency are far inferior to those of the embodiments, indicating that the cleaning order of the silicon material of the present invention in different cleaning agents (first cleaning agent, second cleaning agent, third cleaning agent) has a great influence on the residual metal ions and organic matter on the surface of the silicon material. A reasonable cleaning order helps to more thoroughly remove impurities on the surface of the silicon material.

[0204] It can be seen from Comparative Example 10 that after mixing the components of the first cleaning agent, the second cleaning agent and the third cleaning agent, the silicon material is cleaned by a one-step immersion method, and the residual amount is much larger than that of each embodiment, and it is difficult to effectively remove the metal ions and organic matter on the surface of the silicon material, and the cleaning efficiency is at a medium level. Therefore, the present invention uses three different cleaning agents and adopts a step-by-step cleaning method to perform immersion cleaning in sequence, which is more effective in removing impurities on the surface of the silicon material and causes less loss to the silicon material. The step-by-step cleaning helps each cleaning agent to be better dissolved and dispersed before mixing, and can provide a more uniform and efficient cleaning effect. The mixing of three surfactants to form the first cleaning agent may promote the synergistic effect between different surfactants, improve the wettability of the cleaning solution and the ability to remove pollutants; further, the formation of three cleaning agents can ensure that the chelating agent and the defoaming agent play a role in a specific cleaning stage, avoiding possible interactions or interferences.

[0205] It can be seen from Comparative Examples 11 to 14 that the composition ratio of the first cleaning agent, the second cleaning agent and the third cleaning agent is within the range defined by the exemplary embodiment of the present invention, which can achieve better cleaning effect and cleaning efficiency for the silicon material, while the composition ratio of the first cleaning agent, the second cleaning agent and the third cleaning agent is outside the range defined by the exemplary embodiment of the present invention, which can achieve poor cleaning effect and cleaning efficiency.

[0206] Based on the results in Table 1, the present invention uses a non-ionic surfactant and a defoaming agent with better environmental protection to form a first cleaning agent in a certain proportion, a non-ionic surfactant and hydrofluoric acid are compounded in a certain proportion to form a second cleaning agent, and two chelating agents compounded in a certain proportion are used to form a third cleaning agent, and the silicon material is immersed and cleaned three times in a step-by-step manner. Exemplarily, the first cleaning agent is mainly used to remove particulate matter and organic matter on the surface of the silicon material, and it is low-foam and water-saving; the second cleaning agent can remove the oxide layer and attached metal ions on the surface of the silicon material to prevent heavy metals such as copper from being adsorbed again; the third cleaning agent can remove metal ions. Therefore, the silicon material cleaning agent composition and silicon material cleaning method provided by the exemplary embodiment of the present invention have better cleaning effect on silicon materials, higher cleaning efficiency, high environmental protection, simpler operation and less damage to silicon materials.

[0207] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present invention.

Claims

1. A silicon material cleaning agent composition, characterized in that: include: a first cleaning agent, a second cleaning agent, and a third cleaning agent; Based on 100 parts by weight of the first cleaning agent, the first cleaning agent includes the following components by weight: 5 to 15 parts of the first nonionic surfactant, Defoaming agent 0.05 to 0.15 parts, The balance is pure water; Wherein, the first nonionic surfactant comprises at least two of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyoxyethylene alkylamine, polyoxyethylene alkylolamide, fatty acid diethanolamide and lauroyl diethanolamine; Based on 100 parts by weight of the second cleaning agent, the second cleaning agent includes the following components by weight: 1 to 3 parts of the second nonionic surfactant, 5 to 15 parts of hydrofluoric acid, The balance is pure water; Wherein, the second nonionic surfactant comprises at least one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyoxyethylene alkylamine, polyoxyethylene alkylolamide, fatty acid diethanolamide and lauroyl diethanolamine; Based on 100 parts by weight of the third cleaning agent, the third cleaning agent includes the following components by weight: 1 to 3 parts of diethylenetriaminepenta(methylenephosphonic acid), Hydroxyethylidene diphosphonic acid, 1 to 3 parts, The balance is pure water.

2. The silicon material cleaning agent composition according to claim 1, characterized in that: Based on 100 parts by weight of the first cleaning agent, the first nonionic surfactant includes the following components in parts by weight: 2 to 6 parts of fatty alcohol polyoxyethylene ether, 2 to 6 parts of alkylphenol polyoxyethylene ether, 1 to 3 parts of fatty acid diethanolamide.

3. The silicon material cleaning agent composition according to claim 2, characterized in that: Based on 100 parts by weight of the first cleaning agent, the first nonionic surfactant includes the following components in parts by weight: 3 to 5 parts of fatty alcohol polyoxyethylene ether, 3 to 5 parts of alkylphenol polyoxyethylene ether, 1.5 to 2.5 parts of fatty acid diethanolamide.

4. The silicon material cleaning agent composition according to claim 1, characterized in that: The second nonionic surfactant includes one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether and fatty acid diethanolamide.

5. The silicon material cleaning agent composition according to claim 4, characterized in that: Based on 100 parts by weight of the second cleaning agent, the second cleaning agent includes the following components by weight: 1.5 to 2 parts of the second nonionic surfactant, 8 to 12 parts of hydrofluoric acid, The balance is pure water.

6. The silicon material cleaning agent composition according to claim 1, characterized in that: Based on 100 parts by weight of the third cleaning agent, the third cleaning agent includes the following components by weight: 1.5 to 2.5 parts of diethylenetriamine penta (methylene phosphonic acid), 1.5 to 2.5 parts of hydroxyethylidene diphosphonic acid, The balance is pure water.

7. A method for cleaning silicon material, characterized in that: Using the silicon material cleaning agent composition according to any one of claims 1 to 6, the method comprises: The silicon material is completely immersed in the first cleaning agent, the second cleaning agent and the third cleaning agent in sequence for cleaning.

8. The silicon material cleaning method according to claim 7, characterized in that: The method further comprises: An ultrasonic cleaning step before the silicon material is completely immersed in the second cleaning agent for cleaning; The step of ultrasonic cleaning before the silicon material is completely immersed in the third cleaning agent for cleaning; The silicon material is completely immersed in the third cleaning agent for cleaning and then an ultrasonic cleaning step is performed.

9. The silicon material cleaning method according to claim 7, characterized in that: Before completely immersing the silicon material in the first cleaning agent for cleaning, the method further includes: After removing dust and impurities on the surface of the silicon material, the silicon material is ultrasonically cleaned.

10. The silicon material cleaning method according to any one of claims 7 to 9, characterized in that: After the silicon material is completely immersed in the third cleaning agent for cleaning, the method further includes: The silicon material is dried at a temperature of 80°C to 100°C.

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