A composite cleaning agent for semiconductor target processing and its preparation method

Abstract

The present invention relates to a composite cleaning agent for semiconductor target processing and a preparation method thereof, belonging to the technical field of sputtering coating. The composite cleaning agent comprises, by weight percentage: 8.2-13.5 wt% of a modified decontamination agent, 30-45 wt% of a composite surfactant, 0.9-1.2 wt% of a polyether defoaming agent, and 25-35 wt% of isopropanol, with the balance being high-purity water; during the cleaning process, the nitrogen-oxygen structure in the molecules of the modified decontamination agent can chelate with the metal-based impurities attached to the surface of the target, the multi-branched ester structure in the middle of its molecules has good compatibility with the remaining esters, and the multi-branched polyether hydrophilic chains at the end form a surface hydrophilic coating modification, improving the wettability of the impurities and making them easy to be cleaned and removed, showing excellent cleaning efficiency and cleanliness in actual tests.

Description

Technical Field

[0001] The present invention belongs to the technical field of sputtering coating, and specifically relates to a composite cleaning agent for semiconductor target processing and a preparation method thereof. Background Technique

[0002] A semiconductor target is a raw material used to manufacture semiconductor materials. It is a material with very high purity and plays a crucial role in the process of manufacturing semiconductor chips. When manufacturing semiconductor materials, a pure semiconductor target is placed in a reaction chamber, and through techniques such as ion beam bombardment or magnetron sputtering, the required materials are precipitated and deposited on a substrate to finally form a semiconductor material device; the quality and performance of the target directly affect the quality and performance of the semiconductor device. Therefore, in the semiconductor industry, the requirements for the quality of semiconductor targets are very high.

[0003] The factors affecting the quality of semiconductor targets mainly include two aspects: one is the self-purity of the semiconductor target, which is related to the preparation raw materials and processes of the semiconductor target. The semiconductor targets developed by existing technical means have extremely high crystallinity and almost no obvious influence; the other is that during the application process of the semiconductor target, it needs to undergo processing such as cutting, grinding, and polishing, and a large amount of impurities will remain on the surface, such as metal particles and lipid lubricants remaining after cutting, etc. Generally, cleaning is used to clean the surface; the choice of cleaning agent directly determines the degree and efficiency of the cleaning treatment. In traditional semiconductor industries, tetrachloroethylene, n-propyl bromide, etc. are mainly used as cleaning agents. Although they have good cleaning effects, they all have certain toxic effects, bringing huge challenges to the health of workers and environmental governance; with the development of science and technology, a series of surfactants with amphiphilic properties are synthesized, and the binding property between impurities and the target matrix is intervened through solubilization to achieve the cleaning effect; however, the cleaning functions of these surfactants are single, and generally a large amount of compounding is required to achieve a comprehensive effect. The main practical problems faced are the large amount of surfactant used, low cleaning efficiency, and the unqualified rate of a single cleaning not meeting the requirements of single-process flow production, and multiple cleaning and full inspection processes need to be set up. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background technique, the purpose of the present invention is to provide a composite cleaning agent for semiconductor target processing and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A composite cleaning agent for semiconductor target processing includes, by weight percentage: 8.2 - 13.5 wt% of a modified decontamination agent, 30 - 45 wt% of a composite surfactant, 0.9 - 1.2 wt% of a polyether defoaming agent, and 25 - 35 wt% of isopropanol, with the balance being high-purity water.

[0007] The modified detergent is prepared by the following method:

[0008] Step A1: Mix diethyl iminodiacetate and anhydrous tetrahydrofuran, add a non-metallic base, preheat to 35 - 40 °C, apply mechanical stirring at 100 - 150 rpm, slowly add dichloroethyl ether. After complete addition, continue to heat to 65 - 70 °C for reflux. Control the total addition reaction time of dichloroethyl ether to be 3 - 4 h. After the reaction ends, filter and rotary evaporate the filtrate to remove tetrahydrofuran to obtain an intermediate compound;

[0009] Furthermore, the dosage ratio of diethyl iminodiacetate, dichloroethyl ether, non-metallic base and anhydrous tetrahydrofuran is 0.2 mol: 0.102 - 0.104 mol: 15 - 22 mL: 130 - 180 mL. Using the non-metallic base as an acid-binding agent to promote the substitution of the secondary amine structure in dichloroethyl ether and diethyl iminodiacetate. The reaction process can be represented as follows:

[0010]

[0011] Preferably, the non-metallic base is triethylamine. The hydrochloride formed after capturing the hydrogen chloride generated by the reaction has poor solubility in the solvent and can precipitate out for easy post-treatment.

[0012] Step A2: Mix the intermediate compound, polyethylene glycol monomethyl ether and dimethyl sulfoxide, heat to 90 - 100 °C, apply ultrasonic oscillation at 20 - 28 kHz, intermittently add an organic base catalyst. Control the total addition reaction time of the organic base catalyst to be 6 - 8 h. After the reaction ends, rotary evaporate under reduced pressure to remove dimethyl sulfoxide to obtain the modified detergent;

[0013] Furthermore, the dosage ratio of the intermediate compound, the hydroxyl content of polyethylene glycol monomethyl ether, the organic base catalyst and dimethyl sulfoxide is 0.1 mol: 0.41 - 0.43 mol: 0.25 - 0.32 g: 350 - 450 mL. Under the promotion of the organic base catalyst and high temperature, transesterification occurs between polyethylene glycol monomethyl ether and the ethyl ester structure in the intermediate compound, introducing a hydrophilic polyether structure to the end of the intermediate compound. The reaction process can be represented as follows:

[0014]

[0015] Furthermore, the number average molecular weight of polyethylene glycol monomethyl ether is 200 - 350.

[0016] Furthermore, the organic base catalyst is 4-dimethylaminopyridine.

[0017] Furthermore, the composite surfactant is composed of isomeric tridecyl alcohol polyoxyethylene ether 1303 and surfactant ByfuelL85.

[0018] A preparation method of a composite cleaning agent for semiconductor target processing, comprising the following steps:

[0019] Step S1: High-speed stirring and mixing of a modified decontamination agent, isopropyl alcohol and high-purity water, and vacuum defoaming treatment to obtain a premix;

[0020] Step S2: Adding a composite surfactant and a polyether defoaming agent to the premix under low-speed stirring and mixing to obtain a composite cleaning agent.

[0021] Advantages of the present invention:

[0022] The present invention discloses a composite cleaning agent for semiconductor target processing. A self-developed modified decontamination agent is compounded in the existing surfactant-based cleaning agent to obtain excellent cleaning effects, and the first-pass cleaning qualification rate reaches 100%; the modified decontamination agent is prepared by a substitution reaction of diethyl iminodiacetate and dichloroethyl ether to form an intermediate compound with a branched ethyl ester structure, and then small-molecular-weight polyethylene glycol monomethyl ether is used for transesterification with it at the ethyl ester structure to introduce a hydrophilic polyether structure modification at the end of the intermediate compound; during the cleaning process, the nitrogen-oxygen structure in the modified decontamination agent molecule forms a chelating effect and adheres to the surface of metal-based impurities remaining on the surface after processing such as target cutting and polishing, introducing the hydrophilic structure at the end to the surface of the metal-based impurities to improve the hydrophilicity of its surface, making the metal-based impurities more easily wetted and more easily carried out under ultrasonic cleaning and water flow flushing to achieve the cleaning effect; similarly, the multi-branched ester structure in the middle of the modified decontamination agent molecule has good compatibility with the residual esters during the processing. In a water-based cleaning environment, the ester structure in the modified decontamination agent combines with the residual esters, and under the tension of the water environment, the multi-branched polyether hydrophilic chains at the end are easy to form a coating on the esters, reducing the adhesion of the esters to the target and making it easier to be cleaned and removed; compared with traditional surfactant-based cleaning agents, the cleaning range is wider, impurities mainly composed of metal-based and lipid substances can be removed, and the cleaning efficiency and cleaning degree are higher. Specific embodiments

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] Example 1

[0025] In this example, a composite cleaning agent for semiconductor target processing is prepared, and the specific implementation process is as follows:

[0026] 1) Preparation of a modified decontamination agent

[0027] Step A1: Take diethyl iminodiacetate and anhydrous tetrahydrofuran and feed them into a mixer for mixing. Use triethylamine as a non-metallic base to avoid the influence of metal ion introduction on the product. Preheat to 35°C and stir mechanically at 100 rpm. Take dichloroethyl ether and slowly add it within 2 h. After complete addition, continue to heat up to 65°C for reflux. Control the total addition reaction time of dichloroethyl ether to be 4 h. During the reaction, the dosage ratio of diethyl iminodiacetate, dichloroethyl ether, non-metallic base, and anhydrous tetrahydrofuran is 0.2 mol: 0.102 mol: 15 mL: 130 mL. After the reaction, filter, take the filtrate and rotary evaporate to remove tetrahydrofuran to obtain an intermediate compound.

[0028] Step A2: Take the intermediate compound, polyethylene glycol monomethyl ether (in this example, MPEG-200 from Jiangsu Haian Petrochemical Factory) and dimethyl sulfoxide and feed them into a mixer for mixing. Heat up to 90°C and apply ultrasonic oscillation at 20 kHz. Use 4-dimethylaminopyridine as an organic base catalyst, divide it into three equal parts, and add it intermittently for 1.5 h. After complete addition, continue the constant temperature reaction. Control the total addition reaction time of the organic base catalyst to be 8 h. During the reaction, the dosage ratio of the intermediate compound, the hydroxyl content of polyethylene glycol monomethyl ether, organic base catalyst, and dimethyl sulfoxide is 0.1 mol: 0.41 mol: 0.25 g: 350 mL. After the reaction, rotary evaporate under reduced pressure to remove dimethyl sulfoxide to obtain a modified detergent.

[0029] 2) Prepare a composite cleaning agent

[0030] Take raw materials according to weight percentage:

[0031] 8.2 wt% of the modified detergent, prepared in this example;

[0032] 45 wt% of the composite surfactant, in the examples, it is composed of isomeric tridecyl alcohol polyoxyethylene ether 1303 and surfactant Byfuel L85 mixed in a mass ratio of 2:1, provided by Guangzhou Junxin Chemical Technology Co., Ltd.;

[0033] 1.2 wt% of the polyether defoamer, in the examples, DC-5500 type polyether defoamer is used, provided by Guangzhou Junxin Chemical Technology Co., Ltd.;

[0034] 25 wt% of isopropanol, industrial grade raw material;

[0035] 20.6 wt% of high-purity water.

[0036] Step S1: Take the modified detergent, isopropanol, and high-purity water and add them to a high-speed stirrer, mix at high speed at 1200 rpm for 10 min, and perform vacuum degassing treatment for 5 min to obtain a premix.

[0037] Step S2: Stir the premix at 40 rpm and uniformly add a composite surfactant and a polyether defoamer and mix them evenly to obtain a composite cleaning agent.

[0038] Example 2

[0039] The specific implementation process of preparing the composite cleaning agent for semiconductor target processing in this example is as follows:

[0040] 1) Prepare a modified detergent

[0041] Step A1: Take diethyl iminodiacetate and anhydrous tetrahydrofuran and mix them by feeding. Use triethylamine as a non-metallic base to avoid the influence of the introduction of metal ions on the product. Preheat to 40 °C and mechanically stir at 150 rpm. Take dichloroethyl ether and slowly add it within 1 h. After complete addition, continue to heat up to 70 °C for reflux. Control the total addition reaction time of dichloroethyl ether to be 3 h. During the reaction, the dosage ratio of diethyl iminodiacetate, dichloroethyl ether, non-metallic base, and anhydrous tetrahydrofuran is 0.2 mol: 0.104 mol: 22 mL: 180 mL. After the reaction, filter and take the filtrate to rotary evaporate to remove tetrahydrofuran to obtain an intermediate compound.

[0042] Step A2: Take the intermediate compound, methoxypolyethylene glycol (MPEG-350 from Jiangsu Haian Petrochemical Factory in this example), and dimethyl sulfoxide and mix them by feeding. Heat up to 100 °C and apply ultrasonic oscillation at 28 kHz. Use 4-dimethylaminopyridine as an organic base catalyst and divide it into three equal parts and add it intermittently for 1 h. After complete addition, continue the constant temperature reaction. Control the total addition reaction time of the organic base catalyst to be 6 h. During the reaction, the dosage ratio of the intermediate compound, the hydroxyl content of methoxypolyethylene glycol, the organic base catalyst, and dimethyl sulfoxide is 0.1 mol: 0.43 mol: 0.32 g: 450 mL. After the reaction, perform rotary evaporation under reduced pressure to remove dimethyl sulfoxide to obtain a modified detergent.

[0043] 2) Prepare the composite cleaning agent

[0044] Take raw materials according to weight percentage: 13.5 wt% of the modified detergent (prepared in this example), 30 wt% of the composite surfactant, 1.0 wt% of the polyether defoamer, 35 wt% of isopropanol, and 20.5 wt% of high-purity water.

[0045] Step S1: Take the modified detergent, isopropanol, and high-purity water and add them to a high-speed stirrer, mix them evenly at 1200 rpm for 10 min, and perform vacuum degassing treatment for 5 min to obtain a premix.

[0046] Step S2: Stir the premix at 40 rpm and uniformly add a composite surfactant and a polyether defoamer and mix them evenly to obtain a composite cleaning agent.

[0047] Example 3

[0048] In this embodiment, a composite cleaning agent for semiconductor target processing is prepared, and the specific implementation process is as follows:

[0049] 1) Preparation of modified detergent

[0050] Step A1: Take diethyl iminodiacetate and anhydrous tetrahydrofuran and mix them. Use triethylamine as a non-metallic base to avoid the influence of metal ion introduction on the product. Preheat to 38°C and stir mechanically at 120 rpm. Slowly add dichloroethyl ether within 1.5 h. After complete addition, continue to heat to 68°C for reflux. Control the total addition reaction time of dichloroethyl ether to be 3.5 h. During the reaction, the dosage ratio of diethyl iminodiacetate, dichloroethyl ether, non-metallic base, and anhydrous tetrahydrofuran is 0.2 mol: 0.103 mol: 18 mL: 150 mL. After the reaction, filter and take the filtrate to rotary evaporate to remove tetrahydrofuran to obtain an intermediate compound.

[0051] Step A2: Take the intermediate compound, methoxypolyethylene glycol (MPEG-200 is used in this embodiment, Jiangsu Haian Petrochemical Factory), and dimethyl sulfoxide and mix them. Heat to 95°C and apply ultrasonic oscillation at 25 kHz. Use 4-dimethylaminopyridine as an organic base catalyst and divide it into three equal parts and add it intermittently for 1.2 h. After complete addition, continue the constant temperature reaction. Control the total addition reaction time of the organic base catalyst to be 7 h. During the reaction, the dosage ratio of the intermediate compound, the hydroxyl content of methoxypolyethylene glycol, the organic base catalyst, and dimethyl sulfoxide is 0.1 mol: 0.42 mol: 0.3 g: 400 mL. After the reaction, rotary evaporate under reduced pressure to remove dimethyl sulfoxide to obtain a modified detergent.

[0052] 2) Preparation of composite cleaning agent

[0053] Take raw materials according to weight percentage: 11.7 wt% of modified detergent (prepared in this embodiment), 40 wt% of composite surfactant, 0.9 wt% of polyether defoamer, 27 wt% of isopropanol, and 20.4 wt% of high-purity water.

[0054] Step S1: Put the modified detergent, isopropanol, and high-purity water into a high-speed stirrer, mix them at high speed at 1200 rpm for 10 min, and perform vacuum degassing treatment for 5 min to obtain a premix.

[0055] Step S2: Stir the premix at 40 rpm and uniformly add the composite surfactant and polyether defoamer to mix them to obtain a composite cleaning agent.

[0056] Example 4

[0057] In this embodiment, a composite cleaning agent for semiconductor target processing is prepared, and the specific implementation process is as follows:

[0058] 1) Preparation of modified detergent

[0059] Step A1: Take diethyl iminodiacetate and anhydrous tetrahydrofuran and mix them. Use triethylamine as a non-metallic base to avoid the influence of metal ion introduction on the product. Preheat to 40°C and stir mechanically at 120 rpm. Slowly add dichloroethyl ether within 1.8 h. After complete addition, continue to heat up to 65°C for reflux. Control the total addition reaction time of dichloroethyl ether to be 3.2 h. During the reaction, the dosage ratio of diethyl iminodiacetate, dichloroethyl ether, non-metallic base, and anhydrous tetrahydrofuran is 0.2 mol: 0.103 mol: 20 mL: 160 mL. After the reaction, filter and take the filtrate to rotary evaporate to remove tetrahydrofuran to obtain an intermediate compound.

[0060] Step A2: Take the intermediate compound, methoxypolyethylene glycol (MPEG-200 is used in this example, Jiangsu Haian Petrochemical Factory), and dimethyl sulfoxide and mix them. Heat up to 92°C and apply ultrasonic oscillation at 28 kHz. Use 4-dimethylaminopyridine as an organic base catalyst and divide it into three equal parts and add it intermittently within 1.3 h. After complete addition, continue the constant temperature reaction. Control the total addition reaction time of the organic base catalyst to be 7.5 h. During the reaction, the dosage ratio of the intermediate compound, the hydroxyl content of methoxypolyethylene glycol, organic base catalyst, and dimethyl sulfoxide is 0.1 mol: 0.41 mol: 0.28 g: 420 mL. After the reaction, rotary evaporate under reduced pressure to remove dimethyl sulfoxide to obtain the modified detergent.

[0061] 2) Preparation of compound cleaning agent

[0062] Take raw materials according to weight percentage: 10.4 wt% of modified detergent (prepared in this example), 42 wt% of compound surfactant, 1.2 wt% of polyether defoamer, 26 wt% of isopropanol, and 20.4 wt% of high-purity water.

[0063] Step S1: Take the modified detergent, isopropanol, and high-purity water and add them to a high-speed stirrer, mix them at a high speed of 1200 rpm for 10 min, and perform vacuum degassing treatment for 5 min to obtain a premix.

[0064] Step S2: Stir the premix at 40 rpm and slowly add the compound surfactant and polyether defoamer and mix them evenly to obtain the compound cleaning agent.

[0065] Comparative Example 1

[0066] The implementation process of this comparative example is the same as that of Example 4. The modified detergent is not added to the cleaning agent formula, and the dosage of the compound surfactant is increased to 52.4 wt%.

[0067] Comparative Example 2

[0068] This comparative example is a commercially available wafer-level cleaning agent with the model HY-6215, provided by Shenzhen Huayi Technology Co., Ltd.

[0069] Take the composite cleaning agent stock solutions obtained from the above Examples 1 - 4 and Comparative Examples 1 - 2, and according to the usage standard of Comparative Example 2, mix and dilute the stock solution and distilled water in a mass ratio of 1:10 to prepare a cleaning solution.

[0070] Refer to the GB / T 22237-2008 standard to test the surface tension of the cleaning solution, and refer to the QB / T2117-1995 standard to test the oil removal efficiency of the cleaning agent. The specific test data are shown in Table 1 as follows:

[0071] Table 1

[0072]

[0073] It can be seen from the data in Table 1 that the surface tension of the cleaning agent prepared by the present invention under conventional dilution is below 30 mN / m, which is similar to that of the comparative example. The oil removal efficiency reaches more than 99%, which is significantly better than the existing compound surfactant type cleaning agents, and slightly higher than the existing commercial wafer-level cleaning agents.

[0074] To verify the actual cleaning ability of the obtained composite cleaning agent, take a batch of processed silicon targets for a single cleaning test. A total of 6 groups are set corresponding to the examples and comparative examples, with 100 specimens in each group. Use the SITA FluoScan 3D surface cleanliness automatic detection system to detect the cleanliness level of the silicon targets before and after cleaning. Remove the highest and lowest cleanliness values, calculate the average cleanliness level, and count the number of unqualified silicon targets after cleaning. The specific cleaning method is as follows: preheat the above-prepared cleaning solution to 40 ± 1 °C, add the silicon targets and soak them statically for 20 min, then perform ultrasonic cleaning at 28 kHz for 5 min, take out the target material and rinse it three times with distilled water, and dry it with hot air; the specific test data are shown in Table 2 as follows:

[0075] Table 2

[0076]

[0077]

[0078] It can be seen from the data in Table 2 that the surface cleanliness level of the silicon targets after conventional processing is about 380 RFU. After being treated with the cleaning agent prepared by the present invention, the cleanliness level is not higher than 2 RFU, and all the single-cleaning tests are qualified, showing a more excellent cleaning effect compared with the comparative example.

[0079] In the description of the specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0080] The above content is only an example and explanation of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar ways to substitute, as long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A composite cleaning agent for semiconductor target processing, characterized in that, Comprising by weight percentage: 8.2 - 13.5 wt% of modified detergent, 30 - 45 wt% of compound surfactant, 0.9 - 1.2 wt% of polyether defoamer, and 25 - 35 wt% of isopropanol, with the balance being high-purity water; The modified detergent is prepared by the following method: Step A1: Mix diethyl iminodiacetate and anhydrous tetrahydrofuran, add a non-metallic base and mix, pre-heat to 35 - 40 °C, stir and slowly add dichloroethyl ether, then continue to heat to 65 - 70 °C for reflux, control the total addition reaction time to be 3 - 4 h, after the reaction is completed, filter and rotary evaporate the filtrate to remove tetrahydrofuran to obtain an intermediate compound; Step A2: Mix the intermediate compound, methoxypolyethylene glycol, and dimethyl sulfoxide, heat to 90 - 100 °C, perform ultrasonic oscillation and intermittently add an organic base catalyst, control the total addition reaction time to be 6 - 8 h, after the reaction is completed, rotary evaporate under reduced pressure to remove dimethyl sulfoxide to obtain the modified detergent; The number average molecular weight of methoxypolyethylene glycol is 200 - 350.

2. The composite cleaning agent for semiconductor target processing according to claim 1, wherein, The dosage ratio of diethyl iminodiacetate, dichloroethyl ether, non-metallic base, and anhydrous tetrahydrofuran is 0.2 mol : 0.102 - 0.104 mol : 15 - 22 mL : 130 - 180 mL.

3. The composite cleaning agent for semiconductor target material processing according to claim 2, wherein, The non-metallic base is triethylamine.

4. A composite cleaning agent for semiconductor target processing according to claim 2, characterized in that, The dosage ratio of the intermediate compound, the hydroxyl content of methoxypolyethylene glycol, the organic base catalyst, and dimethyl sulfoxide is 0.1 mol : 0.41 - 0.43 mol : 0.25 - 0.32 g : 350 - 450 mL.

5. The composite cleaning agent for semiconductor target material processing according to claim 4, wherein, The organic base catalyst is 4-dimethylaminopyridine.

6. The composite cleaning agent for semiconductor target processing according to claim 1, wherein, The compound surfactant is composed of isomeric tridecyl alcohol polyoxyethylene ether 1303 and surfactant Byfuel L85 by compounding.

7. A preparation method of a composite cleaning agent for semiconductor target processing according to any one of claims 1-6, characterized in that, Including the following steps: Step S1: Stir and mix the modified detergent, isopropanol, and high-purity water, and perform vacuum defoaming treatment to obtain a premix; Step S2: Add the premix to the compound surfactant and polyether defoamer under stirring and mix well to obtain a compound cleaning agent.

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