Processing method of high-purity silicon material

Abstract

The invention provides a processing method of a high-purity silicon material. The processing method comprises the following steps: obtaining high-purity monocrystalline silicon; processing micropores in the high-purity monocrystalline silicon and then degreasing; performing micropore etching on the degreased high-purity monocrystalline silicon; the etched high-purity monocrystalline silicon is polished; and performing micropore degreasing on the polished high-purity monocrystalline silicon. According to the processing method of the high-purity silicon material provided by the invention, the upper electrode of the vacuum cavity has higher purity, volume resistivity and durability, better plasma corrosion resistance and low-order electric loss, and meanwhile, the manufacturing cost of the upper electrode material of the vacuum cavity can be greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of silicon material processing, and in particular to a method for processing high-purity silicon material. Background Art

[0002] The upper electrode of the vacuum chamber is made of single crystal silicon wafers. The upper electrode is the negative electrode. It is made of silicon rods through a series of precision processing such as slicing, grinding, etching, micro-hole drilling, shape processing, polishing, and cleaning. It is widely used in infrared detection, semiconductors, aerospace, automobiles, medical treatment, electronic consumer products, scientific research and other fields.

[0003] However, the silicon electrode will be gradually corroded and thinned during the process of etching the silicon wafer oxide film. When the thickness of the silicon electrode is reduced to a certain extent, it needs to be replaced with a new silicon electrode. The upper electrode of the vacuum chamber currently on the market has a short service life, poor use effect and high price due to the low purity of the crystals that make up the silicon body, poor corrosion resistance and low durability.

[0004] Therefore, there is an urgent need for a new processing method that can make the upper electrode of the vacuum chamber have higher purity, volume resistivity and durability, better plasma corrosion resistance and low-order electrical loss, and at the same time significantly reduce the manufacturing cost of the upper electrode material of the vacuum chamber. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a method for processing high-purity silicon materials, which uses high-purity single crystal silicon as raw material, performs front-end processing through high-speed and high-precision equipment, and subsequently obtains the processed high-purity silicon material through process flows such as cleaning, etching, polishing, and degreasing of the product.

[0006] The present invention provides a method for processing high-purity silicon material, comprising the following steps:

[0007] Obtain high-purity single-crystal silicon;

[0008] Degreasing after processing micropores in high-purity single-crystal silicon;

[0009] Perform micropore etching on high-purity single-crystal silicon after degreasing;

[0010] Polishing the etched high-purity single crystal silicon;

[0011] Micropore degreasing is performed on polished high-purity single-crystal silicon.

[0012] As a further improvement of the present invention, the degreasing after processing micropores in high-purity single crystal silicon comprises:

[0013] Mixing a water-based cleaning solution on the surface of the silicon material and water in a ratio of 4:1 to obtain a first degreasing solution;

[0014] Degreasing the high-purity single crystal silicon after micropore processing using a first degreasing liquid;

[0015] Use 40HZ ultrasonic cleaning for 8 minutes.

[0016] As a further improvement of the present invention, the water-based cleaning liquid for the surface of the silicon material includes an inorganic salt dispersant, a nonionic surfactant, a polishing agent, and a stripping agent.

[0017] As a further improvement of the present invention, the inorganic salt dispersant comprises potassium carbonate, the nonionic surfactant comprises 2-mercapto-3-butanol, the polishing agent comprises potassium pyrophosphate, and the stripping agent comprises potassium hydroxide.

[0018] As a further improvement of the present invention, the content of the inorganic salt dispersant is 3.9%, the content of the nonionic surfactant is 19%, the content of the polishing agent is 5.5%, and the content of the stripping agent is 3.5%.

[0019] As a further improvement of the present invention, the micropore etching of the degreased high-purity single crystal silicon comprises:

[0020] Mixing 49% hydrogen fluoride and 55% nitric acid in a ratio of 1:4 to obtain a second etching solution;

[0021] Etching the degreased high-purity single crystal silicon using a second etching solution for 30 seconds;

[0022] Rinse with deionized water;

[0023] Use ultrasonic cleaning for 5 minutes.

[0024] As a further improvement of the present invention, the polishing of the etched high-purity single crystal silicon comprises:

[0025] Use a polishing pad with a roughness of 1500 mesh;

[0026] The polishing liquid and water are mixed in a ratio of 10:1 to obtain a third polishing liquid;

[0027] The etched high-purity single-crystalline silicon is polished using the third polishing liquid. The polishing time is 60 minutes and the single-side polishing time is 30 minutes, so that the roughness of the high-purity single-crystalline silicon reaches below 0.025Ra.

[0028] As a further improvement of the present invention, the components and weight ratio of the polishing liquid include 20-40wt% abrasive, 5-10wt% pH adjuster, 0.04-0.05wt% surfactant, 1-10wt% oxidant, and 3-5wt% chelating agent.

[0029] As a further improvement of the present invention, the microporous degreasing of the polished high-purity single crystal silicon comprises:

[0030] Mixing sulfuric acid and hydrogen peroxide in a ratio of 1:1 to obtain a fourth degreasing liquid;

[0031] The polished high-purity single crystal silicon is placed in the fourth degreasing liquid for 10 minutes at a temperature of 130°C;

[0032] Use ultrasonic cleaning for 10 minutes.

[0033] As a further improvement of the present invention, the sulfuric acid content is 95-98%, and the hydrogen peroxide content is 34%.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention provides a processing method for high-purity silicon material, which can make the upper electrode of the vacuum cavity have higher purity, volume resistivity and durability, better plasma corrosion resistance and low-order electrical loss, and can greatly reduce the manufacturing cost of the upper electrode material of the vacuum cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A flow chart of a processing method for high-purity silicon material disclosed in the present invention is shown;

[0037] Figure 2 A schematic diagram of surface B of the high-purity silicon material test sample disclosed in the present invention is shown. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the present invention will be combined with the attached Figure 1 and attached Figure 2 , a clear and complete description of the technical solutions in the embodiments of the present invention is given. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments, wherein steps S1, S2... in the embodiments described in the present invention do not limit the only execution steps of the present invention; the basic principles of the present invention defined in the description of the present invention can be applied to other implementation schemes, variations, improvements, equivalent schemes, and other technical solutions that do not deviate from the spirit and scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] like Figure 1 As shown, the present invention provides a method for processing high-purity silicon material, comprising the following steps:

[0040] S1: Obtain high-purity single crystal silicon;

[0041] Preferably, single crystal silicon with a purity of 99.9999% is used;

[0042] S2: Degreasing after processing micropores in high-purity single crystal silicon;

[0043] In a preferred embodiment, the degreasing after processing micropores in high-purity single crystal silicon comprises:

[0044] S21: mixing a water-based cleaning solution for the surface of the silicon material and water in a ratio of 4:1 to obtain a first degreasing solution;

[0045] In a preferred embodiment, the water-based cleaning liquid for the surface of the silicon material comprises an inorganic salt dispersant, a nonionic surfactant, a polishing agent, and a stripping agent.

[0046] In a preferred embodiment, the inorganic salt dispersant comprises potassium carbonate, the nonionic surfactant comprises 2-mercapto-3-butanol, the polishing agent comprises potassium pyrophosphate, and the stripping agent comprises potassium hydroxide.

[0047] In a preferred embodiment, the content of the inorganic salt dispersant is 3.9%, the content of the nonionic surfactant is 19%, the content of the polishing agent is 5.5%, and the content of the stripping agent is 3.5%.

[0048] S22: Degreasing the high-purity single crystal silicon after the micropores are processed using a first degreasing liquid;

[0049] S23: Use 40HZ ultrasonic cleaning for 8 minutes.

[0050] S3: performing micropore etching on the degreased high-purity single crystal silicon;

[0051] In a preferred embodiment, the micropore etching of the degreased high-purity single crystal silicon comprises:

[0052] S31: mixing 49% hydrogen fluoride and 55% nitric acid in a ratio of 1:4 to obtain a second etching solution;

[0053] S32: Etching the degreased high-purity single crystal silicon using a second etching solution for 30 seconds;

[0054] S33: rinse with deionized water (DI water);

[0055] S34: Use ultrasonic cleaning for 5 minutes.

[0056] S4: polishing the etched high-purity single crystal silicon;

[0057] In a preferred embodiment, the polishing of the etched high-purity single crystal silicon comprises:

[0058] S41: Use a polishing pad with a roughness of 1500 mesh;

[0059] S42: mixing the polishing liquid and water in a ratio of 10:1 to obtain a third polishing liquid;

[0060] In a preferred embodiment, the components and weight ratio of the polishing liquid include 20-40wt% abrasive, 5-10wt% pH adjuster, 0.04-0.05wt% surfactant, 1-10wt% oxidant, and 3-5wt% chelating agent.

[0061] It should be noted that any values ​​within the composition and weight ratio of the polishing liquid belong to the protection scope of the present invention. For example, the wt% of the abrasive can be 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40; the wt% of the pH regulator can be 5, 6, 7, 8, 9, 10; the wt% of the surfactant can be 0.04, 0.041, 0.04 2, 0.043, 0.044, 0.045, 0.046, 0.047, 0.048, 0.049, 0.05; the wt% of the oxidant can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10; the wt% of the chelating agent can be 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.

[0062] S43: Use the third polishing liquid to polish the etched high-purity single-crystalline silicon. The polishing time is 60 minutes, and the single-side polishing time is 30 minutes, so that the roughness of the high-purity single-crystalline silicon reaches below 0.025Ra.

[0063] S5: Perform microporous degreasing on the polished high-purity single crystal silicon.

[0064] In a preferred embodiment, the microporous degreasing of the polished high-purity single crystal silicon comprises:

[0065] S51: mixing sulfuric acid and hydrogen peroxide in a ratio of 1:1 to obtain a fourth degreasing liquid;

[0066] S52: placing the polished high-purity single crystal silicon in a fourth degreasing liquid for 10 minutes at a temperature of 130° C.;

[0067] S53: Use ultrasonic cleaning for 10 minutes.

[0068] In a preferred embodiment, the sulfuric acid content is 95-98%, and the hydrogen peroxide content is 34%.

[0069] The following will provide a detailed description of the embodiments:

[0070] Example 1

[0071] This embodiment provides a method for processing high-purity silicon material, comprising the following steps:

[0072] S1: Using single crystal silicon with a purity of 99.9999%;

[0073] S2: Degreasing after processing micropores in high-purity single crystal silicon, including:

[0074] S21: mixing a water-based cleaning solution for the surface of the silicon material and water in a ratio of 4:1 to obtain a first degreasing solution;

[0075] The water-based cleaning liquid for the surface of the silicon material comprises an inorganic salt dispersant, a nonionic surfactant, a polishing agent and a stripping agent.

[0076] The inorganic salt dispersant comprises potassium carbonate, the nonionic surfactant comprises 2-mercapto-3-butanol, the polishing agent comprises potassium pyrophosphate, and the stripping agent comprises potassium hydroxide.

[0077] The content of the inorganic salt dispersant is 3.9%, the content of the nonionic surfactant is 19%, the content of the polishing agent is 5.5%, and the content of the stripping agent is 3.5%.

[0078] S22: Degreasing the high-purity single crystal silicon after the micropores are processed using a first degreasing liquid;

[0079] S23: Use 40HZ ultrasonic cleaning for 8 minutes.

[0080] S3: Micro-hole etching of high-purity single-crystal silicon after degreasing, including

[0081] S31: mixing 49% hydrogen fluoride and 55% nitric acid in a ratio of 1:4 to obtain a second etching solution;

[0082] S32: Etching the degreased high-purity single crystal silicon using a second etching solution for 30 seconds;

[0083] S33: rinse with deionized water (DI water);

[0084] S34: Use ultrasonic cleaning for 5 minutes.

[0085] S4: Polishing the etched high-purity single crystal silicon, including:

[0086] S41: Use a polishing pad with a roughness of 1500 mesh;

[0087] S42: mixing the polishing liquid and water in a ratio of 10:1 to obtain a third polishing liquid;

[0088] The components and weight ratio of the polishing liquid include 20wt% of abrasive, 5wt% of pH value adjuster, 0.05wt% of surfactant, 10wt% of oxidant and 3wt% of chelating agent.

[0089] S43: Use the third polishing liquid to polish the etched high-purity single-crystalline silicon. The polishing time is 60 minutes, and the single-side polishing time is 30 minutes, so that the roughness of the high-purity single-crystalline silicon reaches below 0.025Ra.

[0090] S5: Micropore degreasing of polished high-purity single crystal silicon, including:

[0091] S51: mixing sulfuric acid and hydrogen peroxide in a ratio of 1:1 to obtain a fourth degreasing liquid;

[0092] S52: placing the polished high-purity single crystal silicon in a fourth degreasing liquid for 10 minutes at a temperature of 130° C.;

[0093] S53: Use ultrasonic cleaning for 10 minutes.

[0094] The content of the sulfuric acid is 95%, and the content of the hydrogen peroxide is 34%.

[0095] Example 2

[0096] This embodiment provides a method for processing high-purity silicon material, comprising the following steps:

[0097] S1: Using single crystal silicon with a purity of 99.9999%;

[0098] S2: Degreasing after processing micropores in high-purity single crystal silicon, including:

[0099] S21: mixing a water-based cleaning solution for the surface of the silicon material and water in a ratio of 4:1 to obtain a first degreasing solution;

[0100] The water-based cleaning liquid for the surface of the silicon material comprises an inorganic salt dispersant, a nonionic surfactant, a polishing agent and a stripping agent.

[0101] The inorganic salt dispersant comprises potassium carbonate, the nonionic surfactant comprises 2-mercapto-3-butanol, the polishing agent comprises potassium pyrophosphate, and the stripping agent comprises potassium hydroxide.

[0102] The content of the inorganic salt dispersant is 3.9%, the content of the nonionic surfactant is 19%, the content of the polishing agent is 5.5%, and the content of the stripping agent is 3.5%.

[0103] S22: Degreasing the high-purity single crystal silicon after the micropores are processed using a first degreasing liquid;

[0104] S23: Use 40HZ ultrasonic cleaning for 8 minutes.

[0105] S3: Micro-hole etching of high-purity single-crystal silicon after degreasing, including

[0106] S31: mixing 49% hydrogen fluoride and 55% nitric acid in a ratio of 1:4 to obtain a second etching solution;

[0107] S32: Etching the degreased high-purity single crystal silicon using a second etching solution for 30 seconds;

[0108] S33: rinse with deionized water (DI water);

[0109] S34: Use ultrasonic cleaning for 5 minutes.

[0110] S4: Polishing the etched high-purity single crystal silicon, including:

[0111] S41: Use a polishing pad with a roughness of 1500 mesh;

[0112] S42: mixing the polishing liquid and water in a ratio of 10:1 to obtain a third polishing liquid;

[0113] The components and weight ratio of the polishing liquid include 40wt% of abrasive, 10wt% of pH value adjuster, 0.04wt% of surfactant, 1wt% of oxidant, and 5wt% of chelating agent.

[0114] S43: Use the third polishing liquid to polish the etched high-purity single-crystalline silicon. The polishing time is 60 minutes, and the single-side polishing time is 30 minutes, so that the roughness of the high-purity single-crystalline silicon reaches below 0.025Ra.

[0115] S5: Micropore degreasing of polished high-purity single crystal silicon, including:

[0116] S51: mixing sulfuric acid and hydrogen peroxide in a ratio of 1:1 to obtain a fourth degreasing liquid;

[0117] S52: placing the polished high-purity single crystal silicon in a fourth degreasing liquid for 10 minutes at a temperature of 130° C.;

[0118] S53: Use ultrasonic cleaning for 10 minutes.

[0119] The content of the sulfuric acid is 98%, and the content of the hydrogen peroxide is 34%.

[0120] Example 3

[0121] This embodiment provides a method for processing high-purity silicon material, comprising the following steps:

[0122] S1: Using single crystal silicon with a purity of 99.9999%;

[0123] S2: Degreasing after processing micropores in high-purity single crystal silicon, including:

[0124] S21: mixing a water-based cleaning solution for the surface of the silicon material and water in a ratio of 4:1 to obtain a first degreasing solution;

[0125] The water-based cleaning liquid for the surface of the silicon material comprises an inorganic salt dispersant, a nonionic surfactant, a polishing agent and a stripping agent.

[0126] The inorganic salt dispersant comprises potassium carbonate, the nonionic surfactant comprises 2-mercapto-3-butanol, the polishing agent comprises potassium pyrophosphate, and the stripping agent comprises potassium hydroxide.

[0127] The content of the inorganic salt dispersant is 3.9%, the content of the nonionic surfactant is 19%, the content of the polishing agent is 5.5%, and the content of the stripping agent is 3.5%.

[0128] S22: Degreasing the high-purity single crystal silicon after the micropores are processed using a first degreasing liquid;

[0129] S23: Use 40HZ ultrasonic cleaning for 8 minutes.

[0130] S3: Micro-hole etching of high-purity single-crystal silicon after degreasing, including

[0131] S31: mixing 49% hydrogen fluoride and 55% nitric acid in a ratio of 1:4 to obtain a second etching solution;

[0132] S32: Etching the degreased high-purity single crystal silicon using a second etching solution for 30 seconds;

[0133] S33: rinse with deionized water (DI water);

[0134] S34: Use ultrasonic cleaning for 5 minutes.

[0135] S4: Polishing the etched high-purity single crystal silicon, including:

[0136] S41: Use a polishing pad with a roughness of 1500 mesh;

[0137] S42: mixing the polishing liquid and water in a ratio of 10:1 to obtain a third polishing liquid;

[0138] The components and weight ratio of the polishing liquid include 30wt% of abrasive, 7.5wt% of pH value adjuster, 0.045wt% of surfactant, 5wt% of oxidant and 4wt% of chelating agent.

[0139] S43: Use the third polishing liquid to polish the etched high-purity single-crystalline silicon. The polishing time is 60 minutes, and the single-side polishing time is 30 minutes, so that the roughness of the high-purity single-crystalline silicon reaches below 0.025Ra.

[0140] S5: Micropore degreasing of polished high-purity single crystal silicon, including:

[0141] S51: mixing sulfuric acid and hydrogen peroxide in a ratio of 1:1 to obtain a fourth degreasing liquid;

[0142] S52: placing the polished high-purity single crystal silicon in a fourth degreasing liquid for 10 minutes at a temperature of 130° C.;

[0143] S53: Use ultrasonic cleaning for 10 minutes.

[0144] The content of the sulfuric acid is 97%, and the content of the hydrogen peroxide is 34%.

[0145] Comparative Example 1

[0146] This comparative example does not adopt the processing method of a high-purity silicon material provided by the embodiment of the present invention, and only performs micro-hole processing on the single crystal silicon.

[0147] Test Example 1: Micropore Diameter

[0148] The single crystal silicon obtained by Examples 1-3 and Comparative Example 1 was used as the test sample, and the micropore diameters of the B surface and the F surface of the test sample were measured using an image measuring instrument, and the measured results are shown in Table 1. The test results show that the micropore diameters of the single crystal silicon in Comparative Example 1 are 0.440-0.460 mm on the B surface and 0.710-0.730 mm on the F surface, which do not meet the production requirements; the micropore diameters of the high-purity single crystal silicon processed in Examples 1-3 are 0.451-0.520 mm on the B surface and 0.721-0.805 mm on the F surface, which reach the ideal range and meet the production requirements.

[0149] Table 1:

[0150]

[0151]

[0152] Test Example 2: Surface Roughness

[0153] The high-purity single crystal silicon processed by the processing method of Example 1 was used as the test sample, and the roughness was measured by a roughness measuring instrument. Figure 2 The surface roughness of the test sample B shown in the figure is measured, and the measured results are shown in Table 2. The test results show that the surface roughness of the high-purity single crystal silicon before polishing is 0.30-0.35Ra, and the surface roughness of the high-purity single crystal silicon after polishing reaches below 0.025Ra, reaching the ideal range value and meeting the production requirements.

[0154] Table 2:

[0155]

[0156] The above-mentioned embodiments, comparative examples, test examples and Tables 1 and 2 prove that, compared with single crystal silicon that has not been processed by the processing method of the present invention, the processing method of the high-purity silicon material provided by the present invention can make the processed high-purity single crystal silicon meet the production requirements, can make the upper electrode of the vacuum chamber have higher purity, volume resistivity and durability, have better plasma corrosion resistance and low-order electrical loss, and at the same time can greatly reduce the manufacturing cost of the upper electrode material of the vacuum chamber.

Claims

1. A method for processing high-purity silicon material, characterized in that: The following steps are involved: Obtain high-purity single-crystal silicon; Degreasing after processing micropores in high-purity single-crystal silicon; Perform micropore etching on high-purity single-crystal silicon after degreasing; Polishing the etched high-purity single crystal silicon; Micropore degreasing is performed on polished high-purity single-crystal silicon.

2. The method for processing high-purity silicon material according to claim 1, characterized in that: The method of degreasing the high-purity single crystal silicon after processing micropores comprises: Mixing a water-based cleaning solution on the surface of the silicon material and water in a ratio of 4:1 to obtain a first degreasing solution; Degreasing the high-purity single crystal silicon after micropore processing using a first degreasing liquid; Use 40HZ ultrasonic cleaning for 8 minutes.

3. The method for processing high-purity silicon material according to claim 2, characterized in that: The water-based cleaning liquid for the surface of the silicon material comprises an inorganic salt dispersant, a nonionic surfactant, a polishing agent and a stripping agent.

4. The method for processing high-purity silicon material according to claim 3, characterized in that: The inorganic salt dispersant comprises potassium carbonate, the nonionic surfactant comprises 2-mercapto-3-butanol, the polishing agent comprises potassium pyrophosphate, and the stripping agent comprises potassium hydroxide.

5. The method for processing high-purity silicon material according to claim 3 or 4, characterized in that: The content of the inorganic salt dispersant is 3.9%, the content of the nonionic surfactant is 19%, the content of the polishing agent is 5.5%, and the content of the stripping agent is 3.5%.

6. The method for processing high-purity silicon material according to claim 1, characterized in that: The micropore etching of the degreased high-purity single crystal silicon comprises: Mixing 49% hydrogen fluoride and 55% nitric acid in a ratio of 1:4 to obtain a second etching solution; Etching the degreased high-purity single crystal silicon using a second etching solution for 30 seconds; Rinse with deionized water; Use ultrasonic cleaning for 5 minutes.

7. The method for processing high-purity silicon material according to claim 1, characterized in that: The step of polishing the etched high-purity single crystal silicon comprises: Use a polishing pad with a roughness of 1500 mesh; The polishing liquid and water are mixed in a ratio of 10:1 to obtain a third polishing liquid; The etched high-purity single-crystalline silicon is polished using the third polishing liquid. The polishing time is 60 minutes and the single-side polishing time is 30 minutes, so that the roughness of the high-purity single-crystalline silicon reaches below 0.025Ra.

8. The method for processing high-purity silicon material according to claim 7, characterized in that: The components and weight ratio of the polishing liquid include 20-40wt% of abrasive, 5-10wt% of pH value regulator, 0.04-0.05wt% of surfactant, 1-10wt% of oxidant and 3-5wt% of chelating agent.

9. The method for processing high-purity silicon material according to claim 1, characterized in that: The microporous degreasing of the polished high-purity single crystal silicon comprises: Mixing sulfuric acid and hydrogen peroxide in a ratio of 1:1 to obtain a fourth degreasing liquid; The polished high-purity single crystal silicon is placed in the fourth degreasing liquid for 10 minutes at a temperature of 130°C; Use ultrasonic cleaning for 10 minutes.

10. The method for processing high-purity silicon material according to claim 9, characterized in that: The sulfuric acid content is 95-98%, and the hydrogen peroxide content is 34%.

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