Cleaning agent, method for removing metal ions using the cleaning agent, and application thereof

Abstract

The present invention relates to the field of semiconductors, and in particular to a cleaning agent, a method for removing metal ions using the cleaning agent, and an application thereof. The cleaning agent comprises a sulfoxide substance, an alkaline compound, and a fluoride; the cleaning agent comprises an element S and an element N; the content of the element S in the cleaning agent is a, the content of the element N in the cleaning agent is b, and the pH value of the cleaning agent is c, satisfying 1≤(a+b)*100 / c≤5. The cleaning agent of the present invention can efficiently remove metal ions, thereby improving the quality and performance of semiconductor materials.

Description

Technical Field

[0001] The invention relates to the field of semiconductors, and in particular to a cleaning agent, a method for removing metal ions using the cleaning agent, and an application thereof. Background Art

[0002] During the preparation and processing of semiconductor materials, the presence of metal ions may have a serious impact on the performance and reliability of semiconductor devices. Metal ion contamination mainly comes from preparation equipment, impurity doping, chemical reagents, metal ion residues in the atmosphere, etc. These metal ion pollutants may accumulate in the device, leading to defects in the crystal structure, changes in electrical properties, and deterioration of interface properties, forming energy levels in the semiconductor material, limiting the migration of electrons and the transmission of carriers. In addition, some metal ions are oxidizing and corrosive, and may form oxides or corrosion products on the surface of the semiconductor material, leading to degradation of device performance and reliability problems. Therefore, it is usually necessary to use a cleaning agent to remove metal ions. However, the cleaning agents used in the prior art are not effective in removing metal ions. Summary of the invention

[0003] The purpose of the present invention is to overcome the above problems existing in the prior art and provide a cleaning agent, a method for removing metal ions using the cleaning agent and an application thereof. The cleaning agent of the present invention can efficiently remove metal ions, thereby improving the quality and performance of semiconductor materials.

[0004] The first aspect of the present invention provides a cleaning agent, which includes a sulfoxide substance, an alkaline compound and a fluoride; the cleaning agent includes element S and element N; the content of element S in the cleaning agent is a, the content of element N in the cleaning agent is b, and the pH value of the cleaning agent is c, satisfying 1≤(a+b)*100 / c≤5.

[0005] The second aspect of the present invention provides a method for removing metal ions using the cleaning agent described in the first aspect of the present invention, the method comprising at least the following steps: (1) pre-treating the object to be cleaned; (2) soaking the object to be cleaned after the pre-treatment in step (1) in the cleaning agent; (3) washing the object to be cleaned after the soaking in step (2); and (4) drying.

[0006] The third aspect of the present invention provides a use of the cleaning agent described in the first aspect of the present invention in removing metal ions from a silicon epitaxial base and / or semiconductor materials.

[0007] Through the above technical solution, the present invention has at least the following advantages compared with the prior art:

[0008] (1) The cleaning agent of the present invention has excellent complexing ability, can effectively remove metal ions on the surface of the object to be cleaned, and can stabilize the metal ions to prevent them from re-precipitating or adsorbing on the surface of the object to be cleaned;

[0009] (2) The method for removing metal ions of the present invention uses the cleaning agent described in the first aspect of the present invention, and can effectively remove metal ions at a relatively low temperature and in a relatively short time.

[0010] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article. DETAILED DESCRIPTION

[0011] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0012] A first aspect of the present invention provides a cleaning agent.

[0013] The cleaning agents in related technologies cannot efficiently remove metal ions, thus affecting the quality and performance of semiconductors. After a long period of extensive research, it was found that under certain alkaline conditions, the use of complex reaction mechanism to remove metal ions has a better effect. The following solutions are proposed:

[0014] (1) Add sulfoxides, alkaline compounds and fluorides to the cleaning agent.

[0015] Sulfoxides have strong complexing ability and can form complexes with metal ions through coordination bonds, so that metal ions are dissolved in the cleaning agent, thereby achieving a cleaning effect. Alkaline compounds have acid neutralization ability, and hydroxide (-OH) also has a certain complexing ability and can form hydrate complexes with metal ions. The specific complexing mechanism is as follows (dimethyl sulfoxide (DMSO) is used as an example for explanation):

[0016] a) Coordinate bond formation: In this step, DMSO, as a ligand, forms a coordination bond with the metal ion through the sulfur atom to form a complex of the metal ion and DMSO;

[0017] b) Solvation: In the solution, water molecules act as solvents, helping metal ions and DMSO complexes approach each other and form hydrate complexes. Water molecules form hydrogen bonds or other non-covalent interactions with metal ions and DMSO complexes through oxygen atoms, stabilizing the formation of the complexes.

[0018] c) Coordination of hydroxide: [M(H2O) n ] n+ +m-OH→[M(H2O) n -(OH) m ] (n-m)+ ;

[0019] Fluorides also have complexing ability and can react with oxides on the metal surface to form easily soluble metal fluorides.

[0020] (2) Regulate the relationship between the content of element S and element N in the cleaning agent and the pH value of the cleaning agent.

[0021] Although the cleaning agent including the above-mentioned combination of substances can have a certain complexing and cleaning ability for metal ions, its cleaning effect is not ideal. After a large number of experiments, it was found that by regulating the content of element S in the cleaning agent, the content of element N and the pH value of the cleaning agent, the metal ions can be removed more efficiently. The sulfur atom in the sulfoxide substance has a strong electrophilicity and can provide lone pairs of electrons to form coordination bonds with metal ions, thereby forming a complex to promote the dissolution and cleaning of metal ions; the lone pairs of electrons on the nitrogen atoms in the alkaline compounds can also form coordination bonds with metal ions. And on the basis of containing fluoride in the solution, when the relationship between the content of element S and element N and the pH value of the cleaning agent is within a specific range, the bonding ability of lone pairs of electrons with metal ions can be significantly improved, and the stability of the complex formed can be improved. Thereby, the efficient removal of metal ions can be guaranteed.

[0022] In the present invention, the cleaning agent may include sulfoxide substances, alkaline compounds and fluorides; the cleaning agent may include element S and element N; the content of element S in the cleaning agent is a (unit: weight %), the content of element N in the cleaning agent is b (unit: weight %), and the pH value of the cleaning agent is c, satisfying 1≤(a+b)*100 / c≤5, for example, (a+b)*100 / c is 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5.

[0023] In one example, 1.7≤(a+b)*100 / c≤3.5.

[0024] In the present invention, the content a of element S in the cleaning agent may be 5-30% by weight, for example, 5, 6, 7, 8, 9, 10, 15, 20, 25 or 30% by weight.

[0025] In one example, the content a of element S in the cleaning agent is 14-25% by weight.

[0026] In the present invention, the content b of element N in the cleaning agent may be 0.1-10 wt %, for example, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 wt %.

[0027] In one example, the content b of the element N in the cleaning agent is 1-3.5 wt %.

[0028] In the present invention, the pH value c of the cleaning agent may be 7-14, for example, 7, 8, 9, 10, 11, 12, 13 or 14.

[0029] In one example, the pH value c of the cleaning agent is 8.4-10.1.

[0030] In the present invention, the sulfoxide substance may include at least one of dimethyl sulfoxide, diethyl sulfoxide, diphenyl sulfoxide, thionyl chloride and benzyl sulfoxide.

[0031] In one example, the sulfoxide substance includes dimethyl sulfoxide and diethyl sulfoxide. The mass ratio of dimethyl sulfoxide to diethyl sulfoxide can be 1:(0.5-4), such as 1:0.5, 1:1, 1:2, 1:3 or 1:4.

[0032] Studies have found that when the sulfoxide substances include dimethyl sulfoxide and diethyl sulfoxide, the metal ion removal ability of the cleaning agent can be further improved. The reasons may be as follows: first, dimethyl sulfoxide and diethyl sulfoxide are polar solvents, and their molecules contain polar groups, which enable them to interact and dissolve with many organic and inorganic substances; the combination of the two can dissolve most inorganic salts, organic compounds and metal complexes, so that the cleaning agent has good solubility and diffusibility during the cleaning process; secondly, dimethyl sulfoxide and diethyl sulfoxide can selectively react with metal ions, dissolve and remove them, and the two have different selectivity for different metal ions, so the combination of the two can more comprehensively dissolve and remove different metal ions; thirdly, when dimethyl sulfoxide and diethyl sulfoxide are combined in a specific mass ratio, they are easy to decompose and degrade, thereby having less adverse effects on the environment; finally, when dimethyl sulfoxide and diethyl sulfoxide are combined in a specific mass ratio, they have a certain corrosion inhibition ability, can form a stable protective film on the surface of the object to be cleaned, can reduce the probability of damage to the object to be cleaned (such as silicon epitaxial base), thereby increasing the service life.

[0033] In the present invention, the alkaline compound may include at least one of triethanolamine, ammonia water, diethanolamine and dimethanolamine.

[0034] In one example, the alkaline compound includes triethanolamine and ammonia water. The mass ratio of triethanolamine to ammonia water can be 1:(1-4), such as 1:1, 1:2, 1:3 or 1:4.

[0035] The study found that when the alkaline compounds include triethanolamine and ammonia, the metal ion removal ability of the cleaning agent can be further improved. The reason may be that triethanolamine and ammonia have different chemical properties and mechanisms of action. The triethanolamine molecule contains three hydroxyl groups and has strong hydrophilicity, which allows it to be effectively dissolved in water. Triethanolamine can also accept protons to produce hydroxide ions (OH - ), so that it can react with some metal ions to form a stable complex in water. The alkalinity and complexing properties of triethanolamine make it have a good cleaning effect on some organic metal compounds. Ammonia water has alkalinity and good hydrophilicity, and can form a protective film on the surface of the object to be cleaned (such as silicon epitaxial base), reducing damage to the object to be cleaned (such as silicon epitaxial base). When the two are used in a specific mass ratio, they can not only have a good removal effect on metal ions, but also reduce the risk of damage to the object to be cleaned (such as silicon epitaxial base); and the harm to operators and the environment is relatively small.

[0036] In the present invention, the fluoride may include at least one of ammonium fluoride, sodium fluoride and potassium fluoride.

[0037] In one example, the fluoride includes ammonium fluoride and potassium fluoride. The mass ratio of ammonium fluoride to potassium fluoride can be 1:(0.5-4), such as 1:0.5, 1:1, 1:2, 1:3 or 1:4.

[0038] Research has found that when fluorides include ammonium fluoride and potassium fluoride, the metal ion removal ability of the cleaning agent can be further improved. The reasons may be: first, the fluoride ions in ammonium fluoride and potassium fluoride can react with metal ions; ammonium fluoride and potassium fluoride have different chemical properties. The synergistic use of these two solutions can give full play to their cleaning ability, improve the comprehensiveness of cleaning, and improve the cleaning effect; secondly, the combination of the two can provide a certain surface protection, prevent the possibility of metal redeposition and oxidation, reduce the adverse effects on the object to be cleaned (such as silicon epitaxial base) during the cleaning process, and maintain the cleaning effect.

[0039] In the present invention, the mass ratio of the sulfoxide substance, the alkaline compound and the fluoride can be (10-40):(1-6):1, for example, 10:1:1, 25:1:1, 40:1:1, 10:3:1, 25:3:1, 40:3:1, 10:6:1, 25:6:1 or 40:6:1.

[0040] In one example, the mass ratio of the sulfoxide substance, the alkaline compound and the fluoride is (15-30):(1-4):1.

[0041] Polyethylene glycol (PEG) is a polymer with multiple redox properties and solubilizing properties. Studies have found that when PEG is included in a cleaning agent, it helps to improve the cleaning effect. The reason may be that PEG has good solubility. When added to a cleaning agent, it can enhance the solubility of the cleaning agent, which helps to efficiently dissolve and remove pollutants. Moreover, PEG can change the surface tension of the cleaning agent, which helps to improve the wettability of the cleaning agent on the surface of the object to be cleaned (such as a silicon epitaxial base), making it have a better cleaning effect. In addition, PEG has certain redox properties and can participate in redox reactions during the cleaning process, which helps to decompose and remove organic pollutants.

[0042] In one example, the cleaning agent further includes polyethylene glycol (PEG).

[0043] In the present invention, PEG may include at least one of PEG-200, PEG-400, PEG-600, PEG-800, PEG-1000, PEG-1500, and PEG-2000.

[0044] The study found that PEG has a specific composition that can ensure its good compatibility with other ingredients in the cleaning agent, avoiding negative effects on the objects being cleaned (such as silicon epitaxial bases), and further improving the cleaning effect of the cleaning agent while ensuring high solubility; and PEG has a certain viscosity, which can play a certain coating role on the complex, thereby improving the cleaning effect.

[0045] In the present invention, PEG includes PEG-400 and PEG-1500.

[0046] In one example, the mass ratio of PEG-400 to PEG-1500 is 1:(0.2-0.5).

[0047] In the present invention, based on the total weight of the cleaning agent, the content of PEG can be 0.5-20% by weight, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20% by weight.

[0048] In one example, based on the total weight of the cleaning agent, the content of PEG is 1-5 weight %.

[0049] In the present invention, the cleaning agent may further include deionized water. Based on the total weight of the cleaning agent, the content of the deionized water may be 10-60% by weight, for example, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60% by weight.

[0050] Research has found that deionized water in cleaning agents can not only promote complexation and dissolution, but also form hydrates with metal ions, thereby affecting the rate and balance of complexation reactions. When the content of deionized water in cleaning agents is within a specific range, it can achieve better results in removing metal ions.

[0051] In one example, based on the total weight of the cleaning agent, the content of the deionized water is 25-45 weight %.

[0052] The cleaning agent of the present invention has excellent complexing ability, can effectively remove metal ions from the object to be cleaned (such as silicon epitaxial base), and can stabilize the metal ions to prevent them from re-precipitating or adsorbing onto the surface of the object to be cleaned (such as silicon epitaxial base).

[0053] The second aspect of the present invention provides a method for removing metal ions using the cleaning agent according to the first aspect of the present invention, the method comprising the following steps:

[0054] (1) Pre-treating the object to be cleaned;

[0055] (2) soaking the object to be cleaned after the pretreatment in step (1) in the cleaning agent;

[0056] (3) washing the object to be cleaned after soaking in step (2);

[0057] (4) Drying.

[0058] In the present invention, in step (1), the object to be cleaned may include a silicon epitaxial susceptor.

[0059] In the present invention, in step (1), the pretreatment may include at least one of removing impurities and removing grease. The pretreatment may also include drying the cleaned object after removing impurities and / or removing grease.

[0060] In the present invention, the solvent used in the pretreatment may include at least one of an organic solvent and a surfactant.

[0061] In the present invention, in step (2), the soaking includes completely soaking the pre-treated object obtained in step (1) in the cleaning agent. The complete soaking means that the cleaning agent immerses the object.

[0062] In the present invention, the soaking time can be 1 minute to 30 minutes, for example, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 20 minutes or 30 minutes.

[0063] In the present invention, the soaking temperature can be 10°C-35°C, for example, 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 25°C, 30°C or 35°C.

[0064] In the present invention, in step (3), the washing includes washing the object to be cleaned after soaking in step (2) with deionized water. The washing may include at least one of spraying, ultrasound and soaking.

[0065] In the present invention, in step (4), the drying can be carried out by conventional means in the art, such as drying with nitrogen or heating in a drying oven.

[0066] In the present invention, the cleaning agent is used at a temperature of 15°C-35°C.

[0067] The method for removing metal ions of the present invention uses the cleaning agent described in the first aspect of the present invention, and can effectively remove metal ions at a relatively low temperature and in a relatively short time.

[0068] The third aspect of the present invention provides a use of the cleaning agent described in the first aspect of the present invention in removing metal ions from a silicon epitaxial base and / or a semiconductor.

[0069] The study found that when the porosity of the silicon epitaxial base is within a specific range, it can increase the contact area between the cleaning agent and the metal ions, improve the diffusion capacity of the cleaning agent, and thus more thoroughly remove the metal ions.

[0070] In the present invention, the porosity of the silicon epitaxial base may be ≤1%, for example, 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2% or 0.1%.

[0071] In one example, the porosity of the silicon epitaxial substrate is 0.2%-0.8%.

[0072] In one example, the porosity of the silicon epitaxial base is 0.1%-0.5%.

[0073] The study found that when the contact angle of the cleaning agent on the silicon epitaxial base is within a specific range, the cleaning agent's wetting ability on the silicon epitaxial base can be increased, thereby improving the cleaning agent's removal effect on metal ions.

[0074] In the present invention, the contact angle of the cleaning agent on the silicon epitaxial base is θ, which can be 0°≤θ≤90°, for example, 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85° or 90°.

[0075] In one example, 0°<θ≤30°.

[0076] The present invention will be described in detail below by way of examples. The examples described in the present invention are only a part of the examples of the present invention, rather than all of the examples. Based on the examples in the present invention, all other examples obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0077] In the following examples, unless otherwise specified, all materials used were commercially available analytical grade.

[0078] Preparation Example

[0079] The following preparation examples are used to prepare the cleaning agent of the present invention.

[0080] Preparation Example 1

[0081] Sulfoxide substances (dimethyl sulfoxide and diethyl sulfoxide, mass ratio of 1:2.5), alkaline compounds (triethanolamine and ammonia water, mass ratio of 1:2.5), fluoride (ammonium fluoride and potassium fluoride, mass ratio of 1:2.5) are added to deionized water in a mass ratio of 20:4:1, and PEG (PEG-400 and PEG-1500, mass ratio of 1:0.3) is added, and stirred evenly, wherein the mass of PEG is 3% of the total mass of the cleaning agent, and the mass of deionized water is 35% of the total mass of the cleaning agent.

[0082] Preparation Example 2

[0083] Sulfoxide substances (dimethyl sulfoxide and diethyl sulfoxide, mass ratio of 1:0.5), alkaline compounds (triethanolamine and ammonia water, mass ratio of 1:1), fluoride (ammonium fluoride and potassium fluoride, mass ratio of 1:0.5) are added to deionized water in a mass ratio of 30:3:1, and PEG (PEG-400 and PEG-1500, mass ratio of 1:0.2) is added, and stirred evenly, wherein the mass of PEG is 1% of the total mass of the cleaning agent, and the mass of deionized water is 25% of the total mass of the cleaning agent.

[0084] Preparation Example 3

[0085] Sulfoxide substances (dimethyl sulfoxide and diethyl sulfoxide, mass ratio of 1:4), alkaline compounds (triethanolamine and ammonia water, mass ratio of 1:4), fluoride (ammonium fluoride and potassium fluoride, mass ratio of 1:4) are added to deionized water in a mass ratio of 15:1:1, and PEG (PEG-400 and PEG-1500, mass ratio of 1:0.5) is added, and stirred evenly, wherein the mass of PEG is 5% of the total mass of the cleaning agent, and the mass of deionized water is 45% of the total mass of the cleaning agent.

[0086] Preparation Example 4

[0087] This group of preparation examples was carried out with reference to Preparation Example 1, except that the sulfoxide substances were changed, specifically:

[0088] In Preparation Example 4a, the sulfoxide substance is a combination of dimethyl sulfoxide and diethyl sulfoxide, wherein the mass ratio of dimethyl sulfoxide to diethyl sulfoxide is 1:0.2;

[0089] Preparation Example 4b, the sulfoxide substance is a combination of dimethyl sulfoxide and diethyl sulfoxide, wherein the mass ratio of dimethyl sulfoxide to diethyl sulfoxide is 1:6;

[0090] Preparation Example 4c, the sulfoxide substance is a combination of dimethyl sulfoxide and diphenyl sulfoxide, wherein the mass ratio of dimethyl sulfoxide to diphenyl sulfoxide is 1:2.5;

[0091] In Preparation Example 4d, the sulfoxide substance is dimethyl sulfoxide.

[0092] Preparation Example 5

[0093] This group of preparation examples was carried out with reference to Preparation Example 1, except that the basic compound was changed, specifically:

[0094] Preparation Example 5a, the alkaline compound is triethanolamine and ammonia water, wherein the mass ratio of triethanolamine to ammonia water is 1:0.5;

[0095] Preparation Example 5b, the alkaline compound is triethanolamine and ammonia water, wherein the mass ratio of triethanolamine to ammonia water is 1:6;

[0096] Preparation Example 5c, the alkaline compound is diethanolamine and ammonia water, wherein the mass ratio of diethanolamine to ammonia water is 1:2.5;

[0097] In Preparation Example 5d, the basic compound is triethanolamine.

[0098] Preparation Example 6

[0099] This group of preparation examples was carried out with reference to Preparation Example 1, except that the fluoride was changed, specifically:

[0100] In Preparation Example 6a, the fluoride is ammonium fluoride and potassium fluoride, wherein the mass ratio of ammonium fluoride to potassium fluoride is 1:0.3;

[0101] In Preparation Example 6b, the fluoride is ammonium fluoride and potassium fluoride, wherein the mass ratio of ammonium fluoride to potassium fluoride is 1:6;

[0102] In Preparation Example 6c, the fluoride is ammonium fluoride and sodium fluoride, wherein the mass ratio of ammonium fluoride to sodium fluoride is 1:2.5;

[0103] In Preparation Example 6d, the fluoride is ammonium fluoride.

[0104] Preparation Example 7

[0105] This group of preparation examples was carried out with reference to Preparation Example 1, except that the mass ratio of the sulfoxide substance, the alkaline compound and the fluoride was changed, specifically:

[0106] Preparation Example 7a, adding sulfoxide substances (dimethyl sulfoxide and diethyl sulfoxide, mass ratio of 1:2.5), alkaline compounds (triethanolamine and ammonia water, mass ratio of 1:2.5), and fluoride (ammonium fluoride and potassium fluoride, mass ratio of 1:2.5) in a mass ratio of 10:5:1;

[0107] In Preparation Example 7b, sulfoxides (dimethyl sulfoxide and diethyl sulfoxide, with a mass ratio of 1:2.5), alkaline compounds (triethanolamine and ammonia water, with a mass ratio of 1:2.5), and fluorides (ammonium fluoride and potassium fluoride, with a mass ratio of 1:2.5) were added in a mass ratio of 10:6:1.

[0108] Preparation Example 8

[0109] This group of preparation examples was carried out with reference to Preparation Example 1, except that PEG was changed, specifically:

[0110] Preparation Example 8a, without adding PEG;

[0111] In Preparation Example 8b, PEG is PEG-400 and PEG-1500, wherein the mass ratio of PEG-400 to PEG-1500 is 1:0.1;

[0112] Preparation Example 8c, PEG is PEG-400 and PEG-1500, wherein the mass ratio of PEG-400 to PEG-1500 is 1:0.8;

[0113] In Preparation Example 8d, PEG is PEG-400.

[0114] Preparation Example 9

[0115] This group of preparation examples was carried out with reference to Preparation Example 1, except that the content of PEG was changed, specifically:

[0116] In Preparation Example 9a, the mass of PEG is 0.5% of the total mass of the cleaning agent;

[0117] In Preparation Example 9b, the mass of PEG is 10% of the total mass of the cleaning agent.

[0118] Preparation Example 10

[0119] This group of preparation examples was carried out with reference to Preparation Example 1, except that the content of deionized water was changed, specifically:

[0120] In Preparation Example 10a, the mass of deionized water is 10% of the total mass of the cleaning agent;

[0121] In Preparation Example 10b, the mass of deionized water is 60% of the total mass of the cleaning agent.

[0122] Comparative Preparation Example 1

[0123] The same method as in Preparation Example 1 was used, except that no sulfoxide was added.

[0124] Comparative Preparation Example 2

[0125] The same method as in Preparation Example 1 was used, except that no basic compound was added.

[0126] Comparative Preparation Example 3

[0127] The same method as in Preparation Example 1 was used, except that no fluoride was added.

[0128] The content a of element S, the content b of element N, the pH value c and the relationship between the three in the cleaning agent prepared in the above preparation example are shown in Table 1.

[0129] Table 1

[0130]

[0131]

[0132] Example

[0133] The following embodiments are used to remove metal ions from a silicon epitaxial substrate.

[0134] Example 1

[0135] Follow these steps:

[0136] (1) Pretreatment: The silicon epitaxial substrate (porosity 0.5%) was scrubbed with acetone to remove visible contaminants on the surface;

[0137] (2) Soaking the silicon epitaxial substrate treated in step (1) in the cleaning agent prepared in Preparation Example 1, ensuring that the cleaning agent can completely cover the surface to be cleaned, at a temperature of 25° C. for 10 minutes;

[0138] (3) treating the silicon epitaxial base treated in step (2) with ultrasound; removing the silicon epitaxial base from the cleaning agent and rinsing it with a deionized water gun to completely remove the residual cleaning solution and impurities;

[0139] (4) Bake in a vacuum dryer at 120°C for 2 hours.

[0140] Example 2

[0141] Follow these steps:

[0142] (1) Pretreatment: The silicon epitaxial substrate (porosity 0.1%) was scrubbed with acetone to remove visible contaminants on the surface;

[0143] (2) Soaking the silicon epitaxial substrate treated in step (1) in the cleaning agent prepared in Preparation Example 2, ensuring that the cleaning agent can completely cover the surface to be cleaned, at a temperature of 15° C. for 30 minutes;

[0144] (3) treating the silicon epitaxial base treated in step (2) with ultrasound; removing the silicon epitaxial base from the cleaning agent and rinsing it with a deionized water gun to completely remove the residual cleaning solution and impurities;

[0145] (4) Bake in a vacuum dryer at 120°C for 2 hours.

[0146] Example 3

[0147] Follow these steps:

[0148] (1) Pretreatment: The silicon epitaxial substrate (porosity 0.3%) was scrubbed with acetone to remove visible contaminants on the surface;

[0149] (2) Soaking the silicon epitaxial substrate treated in step (1) in the cleaning agent prepared in Preparation Example 3, ensuring that the cleaning agent can completely cover the surface to be cleaned, at a temperature of 35° C. for 5 minutes;

[0150] (3) treating the silicon epitaxial base treated in step (2) with ultrasound; removing the silicon epitaxial base from the cleaning agent and rinsing it with a deionized water gun to completely remove the residual cleaning solution and impurities;

[0151] (4) Bake in a vacuum dryer at 120°C for 2 hours.

[0152] Examples 4-11 were carried out with reference to Example 1, except that different cleaning agents and silicon epitaxial substrates with different porosities were used, as shown in Table 2. Comparative Examples 1-3 were carried out with reference to Example 1, except that different cleaning agents were used, as shown in Table 2.

[0153] Comparative Example 4

[0154] The same procedure is carried out as in Example 1, except that a commercially available cleaning agent is used.

[0155] Table 2

[0156]

[0157]

[0158] Test Case

[0159] (1) Contact angle test

[0160] The contact angles of the cleaning agents in the embodiments and comparative examples on the silicon epitaxial substrate were tested, and the specific testing method is as follows:

[0161] 1. Prepare samples:

[0162] Clean the silicon epitaxial base to ensure that the surface is free of impurities, grease or other contaminants;

[0163] 2. Dropping liquid:

[0164] Using a microsyringe, drop the cleaning agents in the embodiments and comparative examples onto the sample surface;

[0165] 3. Measure the contact angle:

[0166] The contact angle meter was used to measure the angle between the contact line (i.e., the line segment where the droplet intersects the sample surface) and the sample surface, and the results are recorded in Table 2.

[0167] (2) Cleaning effect

[0168] The silicon epitaxial substrate cleaned by the cleaning agent was subjected to an inductively coupled plasma mass spectrometry (ICP-MS) test to detect the concentration of metal ions remaining on the silicon epitaxial substrate. The results are recorded in Table 2.

[0169] It can be seen from Table 2 that the cleaning agent of the present invention and the cleaning agent of the comparative example used to clean the silicon epitaxial base can significantly reduce the concentration of metal ions remaining on the silicon epitaxial base.

[0170] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A cleaning agent for removing metal ions from a silicon epitaxial base and / or semiconductor material, characterized in that: The cleaning agent includes sulfoxide substances, alkaline compounds and fluorides; the cleaning agent includes element S and element N; the content of element S in the cleaning agent is a, the content of element N in the cleaning agent is b, the pH value of the cleaning agent is c, and 1.7≤(a+b)*100 / c≤3.5 is satisfied; the cleaning agent also includes polyethylene glycol; the porosity of the silicon epitaxial base is 0.1%-0.5%.

2. The use according to claim 1, characterized in that: a is 5-30 wt %; and / or, b is 0.1-10 wt %; and / or, c is 7-14.

3. The use according to claim 2, characterized in that: a is 14-25 wt %; and / or, b is 1-3.5 wt %; and / or, c is 8.4-10.

1.

4. The use according to claim 1, characterized in that: The sulfoxide substance includes at least one of dimethyl sulfoxide, diethyl sulfoxide, diphenyl sulfoxide, thionyl chloride and benzyl sulfoxide; and / or, the alkaline compound comprises at least one of triethanolamine, ammonia, diethanolamine and dimethanolamine; And / or, the fluoride includes at least one of ammonium fluoride, sodium fluoride and potassium fluoride.

5. The use according to claim 4, characterized in that: The sulfoxide substances include dimethyl sulfoxide and diethyl sulfoxide; and / or, the alkaline compound comprises triethanolamine and ammonia; And / or, the fluoride includes ammonium fluoride and potassium fluoride.

6. The use according to claim 5, characterized in that: The mass ratio of dimethyl sulfoxide to diethyl sulfoxide is 1:(0.5-4); and / or, the mass ratio of triethanolamine to aqueous ammonia is 1:(1-4); And / or, the mass ratio of ammonium fluoride to potassium fluoride is 1:(0.5-4).

7. The use according to claim 1, characterized in that: The mass ratio of the sulfoxide substance, the alkaline compound and the fluoride is (10-40):(1-6):

1.

8. The use according to claim 1 or 2, characterized in that: The contact angle of the cleaning agent on the silicon epitaxial base is θ, 0°≤θ≤90°.

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