CN114420776A - Method for reducing cost of silicon wafer production line and improving open-circuit pressure - Google Patents
Method for reducing cost of silicon wafer production line and improving open-circuit pressure Download PDFInfo
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- CN114420776A CN114420776A CN202210037850.3A CN202210037850A CN114420776A CN 114420776 A CN114420776 A CN 114420776A CN 202210037850 A CN202210037850 A CN 202210037850A CN 114420776 A CN114420776 A CN 114420776A
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 166
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 166
- 239000010703 silicon Substances 0.000 title claims abstract description 166
- 238000000034 method Methods 0.000 title claims abstract description 69
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 54
- 235000012431 wafers Nutrition 0.000 claims abstract description 163
- 238000004140 cleaning Methods 0.000 claims abstract description 33
- 239000007788 liquid Substances 0.000 claims abstract description 19
- 229910052581 Si3N4 Inorganic materials 0.000 claims abstract description 17
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims abstract description 17
- 238000005498 polishing Methods 0.000 claims abstract description 16
- 230000001681 protective effect Effects 0.000 claims abstract description 16
- 239000003513 alkali Substances 0.000 claims abstract description 13
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims abstract description 13
- 238000009792 diffusion process Methods 0.000 claims abstract description 11
- 239000007888 film coating Substances 0.000 claims abstract description 11
- 238000009501 film coating Methods 0.000 claims abstract description 11
- 238000001035 drying Methods 0.000 claims abstract description 9
- 238000007747 plating Methods 0.000 claims abstract description 9
- JLTRXTDYQLMHGR-UHFFFAOYSA-N trimethylaluminium Chemical compound C[Al](C)C JLTRXTDYQLMHGR-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000008367 deionised water Substances 0.000 claims abstract description 7
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 7
- 230000003647 oxidation Effects 0.000 claims abstract description 7
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 7
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 28
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 24
- 238000002156 mixing Methods 0.000 claims description 20
- 239000000654 additive Substances 0.000 claims description 17
- 230000000996 additive effect Effects 0.000 claims description 17
- 239000000463 material Substances 0.000 claims description 3
- 238000011109 contamination Methods 0.000 claims 1
- 239000012634 fragment Substances 0.000 abstract description 14
- 230000008021 deposition Effects 0.000 abstract description 7
- 238000002161 passivation Methods 0.000 abstract description 7
- 239000013585 weight reducing agent Substances 0.000 abstract description 7
- 238000005406 washing Methods 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 11
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 8
- 239000007789 gas Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 239000012530 fluid Substances 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- 230000004580 weight loss Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000005215 recombination Methods 0.000 description 3
- 230000006798 recombination Effects 0.000 description 3
- 238000002310 reflectometry Methods 0.000 description 3
- 238000004904 shortening Methods 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006388 chemical passivation reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000013467 fragmentation Methods 0.000 description 1
- 238000006062 fragmentation reaction Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0236—Special surface textures
- H01L31/02363—Special surface textures of the semiconductor body itself, e.g. textured active layers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02041—Cleaning
- H01L21/02043—Cleaning before device manufacture, i.e. Begin-Of-Line process
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0216—Coatings
- H01L31/02161—Coatings for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/02167—Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells
- H01L31/02168—Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells the coatings being antireflective or having enhancing optical properties for the solar cells
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
- H01L31/1804—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof comprising only elements of Group IV of the Periodic Table
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Microelectronics & Electronic Packaging (AREA)
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Abstract
The invention discloses a method for reducing the cost of a silicon wafer production line and improving open pressure, which comprises the following steps of (1) cleaning a batch of silicon wafers on the production line to remove surface dirt; (2) washing with deionized water and drying; (3) plating a protective film on the back of the silicon wafer; (4) texturing the silicon wafer to obtain a silicon wafer with a single-sided textured surface; (5) carrying out diffusion and PSG processes; (6) preparing a silicon wafer weight reducing liquid, and placing the silicon wafer in the weight reducing liquid for alkali polishing to reduce the weight of the silicon wafer; (7) carrying out oxidation treatment after weight reduction; (8) then, carrying out aluminum oxide and silicon nitride integrated film coating on the back of the silicon wafer; (9) and carrying out the silicon wafer production line process normally. The method provided by the invention is a single-side texturing process, and can reduce the cost and the fragment rate of the silicon wafer; the back of the prepared silicon wafer is an almost complete plane, the specific surface area is small, the deposition of a passivation film can be more uniform, the deposition time is reduced, the efficiency is improved, the consumption of trimethyl aluminum and special gas can be saved, and the cost is reduced.
Description
Technical Field
The invention relates to the technical field of solar cells, in particular to a method for reducing the cost of a silicon wafer production line and improving the open-circuit voltage.
Background
Under the current industry background, with the rapid expansion of the battery plate market, the silicon raw material is in short supply, the supply and demand of the original silicon wafer are insufficient, and the cost of the silicon wafer is continuously increased; low-thickness silicon wafers become the mainstream of future development, the thickness of 165 microns or even 160 microns is generated at present, but the low-thickness silicon wafers can cause the problem that the fragment rate of a production line continuously rises, so that a process for reducing the weight loss of a wet section and reducing the cost and the fragment rate of the silicon wafers is urgently needed.
The profit margin of the battery piece market is improved, the main stream is cost reduction and efficiency improvement, and besides the cost reduction of the silicon chip, the consumption of chemicals is also reduced. The passivated emitter back contact (PERC) battery is characterized in that the back structure and the current leading-out mode are different, the conventional battery utilizes a p + + layer on the back to repel negative charges away from the back of the battery, and the recombination rate is still as high as 500-5000 cm/s. The industrial PERC battery adopts the laminated passivation of aluminum oxide/silicon nitride, and utilizes the passivation effect of a fixed negative charge field in the aluminum oxide and the chemical passivation of the silicon oxide formed in the sintering process, so that the back surface recombination rate is greatly reduced to 10 cm/s. The polishing of the back surface of the PERC cell can reduce the specific surface area of the back surface to reduce the recombination rate, improve the amplified-Voc and also increase the internal reflection of the cell. The existing battery piece preparation process is high in consumption of chemicals, so that the cost is high, and the weight of a double-sided textured silicon wafer of the existing battery piece preparation process is reduced greatly, so that the fragment rate cannot be guaranteed.
Disclosure of Invention
Aiming at the problems of high cost caused by large consumption of chemicals in the process, high fragment rate caused by more weight reduction of a silicon wafer in the preparation process and the like in the conventional battery piece preparation process, the invention provides a method which is simple in process, can reduce the cost of a silicon wafer production line and can improve the open pressure of a battery piece.
The invention is realized by the following technical scheme:
a method for reducing the cost of a silicon wafer production line and improving the open pressure is characterized by comprising the following sequential steps of:
(1) cleaning a batch of silicon wafers on a production line to remove surface dirt;
(2) cleaning the cleaned silicon wafer with deionized water again and drying;
(3) plating a protective film on the back of the silicon wafer to be used as a texturing mask;
(4) texturing is carried out on the batch of silicon wafers, the protective film can be synchronously removed during texturing, and silicon wafers with single-sided textured surfaces are obtained in batch;
(5) carrying out diffusion and PSG processes on the obtained silicon wafer; after the silicon wafer diffusion process, a layer of PSG is formed on the surface of the silicon wafer and needs to be removed, and the PSG is generally washed away by a hydrofluoric acid solution;
(6) preparing a silicon wafer weight reducing liquid, and then placing the silicon wafer in the weight reducing liquid for alkali polishing to reduce the weight of the silicon wafer on a production line;
(7) carrying out oxidation treatment after the weight of the silicon wafer is reduced;
(8) then carrying out aluminum oxide and silicon nitride integrated film coating on the back of the silicon wafer;
(9) and carrying out the silicon wafer production line process normally.
Specifically, the method for reducing the cost of the silicon wafer production line and improving the open pressure is a single-side texturing process, and can reduce the cost and the fragment rate of the silicon wafer. Wherein: the single-side texturing is realized by plating a protective film on the back side of the silicon wafer in advance, the protective film on the back side can play a role in protecting the back side of the silicon wafer when the silicon wafer is textured, namely, the texturing is performed on one side of the silicon wafer, the protective film on the back side can be synchronously removed after the silicon wafer is textured, the silicon wafer with the single-side textured surface can be formed, the back side of the silicon wafer is a flat and flat surface, then, when an aluminum oxide passivation film is plated on the back side, the deposition of the passivation film can be more uniform, the deposition time can be reduced, the consumption of trimethyl aluminum can be saved, and the cost of a silicon wafer production line can be reduced.
Specifically, the method for reducing the cost of the silicon wafer production line and increasing the open pressure can reduce the overall weight loss of the silicon wafer in the wet process section, reduce the consumption of chemicals and reduce the increase of the amplified-Voc. The single-sided texturing silicon wafer with the back surface without the pyramid structure is prepared by the method, and because the pyramid surface structure does not exist before the silicon wafer is polished, the pyramid structure does not need to be polished under the condition of low weight reduction, only the edge removing and back surface cleaning effects are realized, and the back surface polishing under the condition of low weight reduction is realized.
Further, the method for reducing the cost of the silicon wafer production line and improving the open pressure comprises the following steps: mixing a potassium hydroxide solution and hydrogen peroxide to prepare a cleaning solution, placing the silicon wafer in the cleaning solution, and cleaning at 50-60 ℃ for 200-300 seconds to remove the dirt on the surface of the silicon wafer.
Further, the method for reducing the cost of the silicon wafer production line and improving the open pressure comprises the following steps: the concentration of the potassium hydroxide solution is 0.1-0.5 wt%; the volume ratio of the potassium hydroxide solution to the hydrogen peroxide is 1: (10-15).
Further, the method for reducing the cost of the silicon wafer production line and improving the open pressure comprises the following steps: the drying temperature in the step (2) is 80-85 ℃.
Further, the method for reducing the cost of the silicon wafer production line and improving the open pressure comprises the following steps: the protective film in the step (3) is a silicon nitride film.
Further, the method for reducing the cost of the silicon wafer production line and improving the open pressure comprises the following steps: preparing a silicon wafer weight reducing liquid, then placing the silicon wafer in the weight reducing liquid, and carrying out alkali polishing at 60-65 ℃ for 145-155 seconds to reduce the weight of the silicon wafer of the production line by 0.11-0.13 g.
Further, the method for reducing the cost of the silicon wafer production line and improving the open pressure comprises the following steps: the silicon wafer weight loss liquid is formed by mixing a potassium hydroxide solution and an additive.
Further, the method for reducing the cost of the silicon wafer production line and improving the open pressure comprises the following steps: the concentration of the potassium hydroxide solution is 0.1-0.5 wt%; the volume ratio of the potassium hydroxide solution to the additive is (5-8): 1; the additive is Tuobang BP 63.
Preferably, the alkali polishing time and the concentration of the silicon wafer weight reducing liquid are particularly important in the method provided by the invention, and the weight reduction of the silicon wafer is strictly controlled to be 0.11-0.13g by adjusting the alkali polishing time and the concentration of the liquid medicine, so that the fragment rate of the silicon wafer in a production line is ensured, and the open pressure is increased.
Further, the method for reducing the cost of the silicon wafer production line and improving the open pressure comprises the following steps: the material used for the aluminum oxide film plating in the step (8) is trimethyl aluminum. The step can adopt equipment purchased from Jiejiejia to carry out aluminum oxide and silicon nitride integrated film coating; the film thickness can be controlled by shortening the film coating time and reducing the gas flow.
The invention has the beneficial effects that:
(1) the method for reducing the cost of the silicon wafer production line and improving the open pressure is a single-side texturing process, and can reduce the cost and the fragment rate of the silicon wafer; the back of the prepared silicon wafer is an almost complete plane, and the specific surface area is small, so that the deposition of a passivation film is more uniform, the deposition time is reduced, the efficiency is improved, the consumption of trimethyl aluminum and special gas can be saved, and the cost is reduced.
(2) The single-sided texturing sheet with the back surface without the pyramid structure prepared by the method has no pyramid surface structure before the silicon wafer is polished, so that under the condition of low weight reduction, the pyramid structure does not need to be polished, only the edge removing and back surface cleaning effects are realized, and the back surface polishing under the condition of low weight reduction is realized. Meanwhile, the back of the silicon wafer does not need to be polished to remove the pyramid tip, so that the consumption of chemicals is saved, and the process cost of a production line is reduced.
(3) The method reduces the texturing and alkali polishing weight loss, reduces the silicon wafer cost and the fragment rate, and reduces the consumption of the plating trimethyl aluminum and the special gas.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to specific embodiments, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
A method for reducing the cost of a silicon wafer production line and improving the open pressure is characterized by comprising the following sequential steps of:
(1) mixing 0.5 wt% potassium hydroxide solution with hydrogen peroxide to prepare cleaning solution, then placing a batch of silicon wafers on a production line into the cleaning solution, and cleaning for 300 seconds at 60 ℃ to remove dirt on the surfaces of the silicon wafers; wherein: the volume ratio of the potassium hydroxide solution to the hydrogen peroxide is 1: 12 mixing to prepare cleaning fluid;
(2) cleaning the cleaned silicon wafer with deionized water again and drying at 80 ℃;
(3) plating a silicon nitride protective film on the back of the silicon wafer to be used as a texturing mask;
(4) performing normal process texturing on the batch of silicon wafers, and synchronously removing the silicon nitride protective film on the back of the silicon wafers while texturing to obtain silicon wafers with single-sided textured surfaces in batch;
(5) carrying out normal diffusion and PSG processes on the obtained silicon wafer; after the diffusion process, a layer of PSG is formed on the surface of the silicon wafer and needs to be removed (generally, the PSG is removed by a hydrofluoric acid solution);
(6) mixing a potassium hydroxide solution with the concentration of 0.3 wt% with an additive to prepare a silicon wafer weight reducing liquid, then placing the silicon wafer in the weight reducing liquid, and carrying out alkali polishing at 64 ℃ for 150 seconds to reduce the weight of the silicon wafer on a production line by 0.12 g; wherein: the volume ratio of the potassium hydroxide solution to the additive is 6: 1, mixing; the additive is Tuobang BP 63;
(7) carrying out normal oxidation treatment after the weight of the silicon wafer is reduced;
(8) then, adopting equipment purchased from Jie Jia Chuan to carry out aluminum oxide and silicon nitride integrated film coating on the back of the silicon wafer; the film thickness can be controlled by shortening the film coating time and reducing the gas flow; wherein: the material used for coating is trimethyl aluminum and special gas; because one surface texturing is reduced in the process, the back surface of the silicon wafer is a complete plane without a pyramid surface structure, the specific surface area is small, the deposition of a passivation film is more uniform due to the flat surface, the film coating time can be reduced, and the consumption of trimethyl aluminum and special gas can be saved, so that the consumption of chemicals is reduced, and the production line cost is reduced;
(9) and carrying out the silicon wafer production line process normally.
Statistics show that the fragment rate of the production line is about 0.02% after the improved method is adopted.
Example 2
A method for reducing the cost of a silicon wafer production line and improving the open pressure comprises the following sequential steps:
(1) mixing 0.3 wt% potassium hydroxide solution with hydrogen peroxide to prepare cleaning solution, then placing a batch of silicon wafers on a production line into the cleaning solution, and cleaning for 250 seconds at 50 ℃ to remove dirt on the surfaces of the silicon wafers; wherein: the volume ratio of the potassium hydroxide solution to the hydrogen peroxide is 1: 10 mixing to prepare cleaning fluid;
(2) cleaning the cleaned silicon wafer with deionized water again and drying at 85 ℃;
(3) plating a silicon nitride protective film on the back of the silicon wafer to be used as a texturing mask;
(4) performing normal process texturing on the batch of silicon wafers, and synchronously removing the silicon nitride protective film on the back of the silicon wafers while texturing to obtain silicon wafers with single-sided textured surfaces in batch;
(5) carrying out normal diffusion and PSG processes on the obtained silicon wafer; after the diffusion process, a layer of PSG is formed on the surface of the silicon wafer and needs to be removed (generally, the PSG is removed by a hydrofluoric acid solution);
(6) mixing a potassium hydroxide solution with the concentration of 0.1 wt% with an additive to prepare a silicon wafer weight reducing liquid, then placing the silicon wafer in the weight reducing liquid, and carrying out alkali polishing at 65 ℃ for 155 seconds to reduce the weight of the silicon wafer on a production line by 0.11 g; wherein: the volume ratio of the potassium hydroxide solution to the additive is 5: 1, mixing; the additive is Tuobang BP 63;
(7) carrying out normal oxidation treatment after the weight of the silicon wafer is reduced;
(8) then, adopting equipment purchased from Jie Jia Chuan to carry out aluminum oxide and silicon nitride integrated film coating on the back of the silicon wafer;
(9) and carrying out the silicon wafer production line process normally.
Statistics show that the fragment rate of the production line is about 0.02% after the improved method is adopted.
Example 3
A method for reducing the cost of a silicon wafer production line and improving the open pressure comprises the following sequential steps:
(1) mixing 0.1 wt% potassium hydroxide solution with hydrogen peroxide to prepare cleaning solution, then placing a batch of silicon wafers on a production line into the cleaning solution, and cleaning for 200 seconds at 55 ℃ to remove dirt on the surfaces of the silicon wafers; wherein: the volume ratio of the potassium hydroxide solution to the hydrogen peroxide is 1: 15 mixing to prepare cleaning fluid;
(2) cleaning the cleaned silicon wafer with deionized water again and drying at 83 ℃;
(3) plating a silicon nitride protective film on the back of the silicon wafer to be used as a texturing mask;
(4) performing normal process texturing on the batch of silicon wafers, and synchronously removing the silicon nitride protective film on the back of the silicon wafers while texturing to obtain silicon wafers with single-sided textured surfaces in batch;
(5) carrying out normal diffusion and PSG processes on the obtained silicon wafer; after the diffusion process, a layer of PSG is formed on the surface of the silicon wafer and needs to be removed (generally, the PSG is removed by a hydrofluoric acid solution);
(6) mixing a potassium hydroxide solution with the concentration of 0.5 wt% with an additive to prepare a silicon wafer weight reducing liquid, then placing the silicon wafer in the weight reducing liquid, and performing alkali polishing at 60 ℃ for 150 seconds to reduce the weight of the silicon wafer on a production line by 0.13 g; wherein: the volume ratio of the potassium hydroxide solution to the additive is 8: 1, mixing; the additive is Tuobang BP 63;
(7) carrying out normal oxidation treatment after the weight of the silicon wafer is reduced;
(8) then, adopting equipment purchased from Jie Jia Chuan to carry out aluminum oxide and silicon nitride integrated film coating on the back of the silicon wafer;
(9) and carrying out the silicon wafer production line process normally.
Statistics show that the fragment rate of the production line is about 0.02% after the improved method is adopted.
Comparative example 1
A method for reducing the cost of a silicon wafer production line and improving the open pressure comprises the following sequential steps:
(1) mixing 0.5 wt% potassium hydroxide solution with hydrogen peroxide to prepare cleaning solution, then placing a batch of silicon wafers on a production line into the cleaning solution, and cleaning for 300 seconds at 60 ℃ to remove dirt on the surfaces of the silicon wafers; wherein: the volume ratio of the potassium hydroxide solution to the hydrogen peroxide is 1: 12 mixing to prepare cleaning fluid;
(2) cleaning the cleaned silicon wafer with deionized water again and drying at 60 ℃;
(3) texturing the silicon wafer by a normal process to obtain a silicon wafer with double-sided textured surfaces;
(4) carrying out normal diffusion and PSG processes on the obtained silicon wafer;
(5) mixing a potassium hydroxide solution with the concentration of 0.3 wt% with an additive to prepare a silicon wafer weight reducing liquid, then placing the silicon wafer in the weight reducing liquid, and carrying out alkali polishing at 64 ℃ for 150 seconds to reduce the weight of the silicon wafer on a production line by 0.12 g; wherein: the volume ratio of the potassium hydroxide solution to the additive is 4.5: 1, mixing;
(6) carrying out normal oxidation treatment after the weight of the silicon wafer is reduced;
(7) then, adopting equipment purchased from Jie Jia Chuan to carry out aluminum oxide and silicon nitride integrated film coating on the back of the silicon wafer;
(8) and carrying out the silicon wafer production line process normally.
The difference between the comparative example 1 and the example 1 is that the comparative example 1 is double-sided texturing, and the rest is the same as the example 1; statistics show that the fragment rate of the production line is about 0.05% after the method of comparative example 1 is implemented; therefore, the fragmentation rate of the silicon wafer can be reduced by about 0.03% by single-sided texturing compared with double-sided texturing under the same conditions; namely, the method provided by the invention can reduce the silicon wafer fragment rate of the production line by about 0.03 percent.
Comparative example 2
The comparative example 2 is different from the above comparative example 1 in that the weight of the silicon wafer after alkali polishing in the comparative example 2 is reduced by 0.23g, and the rest is the same as that in the comparative example 1; comparative example 2 is also double-sided texturing.
The silicon wafer backside reflectivity on the production line of example 1 above was tested to be 56.37%, whereas the silicon wafer backside reflectivity of comparative example 2 was about 44.98%; therefore, the method provided by the invention can improve the back surface reflectivity of the silicon wafer and can improve the open pressure of the silicon wafer.
The above-mentioned preferred embodiments of the present invention are provided for illustration only and not for the purpose of limiting the invention. Obvious variations or modifications of the present invention are within the scope of the present invention.
Claims (9)
1. A method for reducing the cost of a silicon wafer production line and improving the open pressure is characterized by comprising the following sequential steps of:
(1) cleaning a batch of silicon wafers on a production line to remove surface dirt;
(2) cleaning the cleaned silicon wafer with deionized water again and drying;
(3) plating a protective film on the back of the silicon wafer to be used as a texturing mask;
(4) texturing is carried out on the batch of silicon wafers, the protective film can be synchronously removed during texturing, and silicon wafers with single-sided textured surfaces are obtained in batch;
(5) carrying out diffusion and PSG processes on the obtained silicon wafer;
(6) preparing a silicon wafer weight reducing liquid, and then placing the silicon wafer in the weight reducing liquid for alkali polishing to reduce the weight of the silicon wafer;
(7) carrying out oxidation treatment after the weight of the silicon wafer is reduced;
(8) then carrying out aluminum oxide and silicon nitride integrated film coating on the back of the silicon wafer;
(9) and carrying out the silicon wafer production line process normally.
2. The method as claimed in claim 1, wherein the step (1) comprises mixing potassium hydroxide solution with hydrogen peroxide to obtain a cleaning solution, and cleaning the silicon wafer in the cleaning solution at 50-60 deg.C for 200-300 s to remove the contamination on the surface of the silicon wafer.
3. The method of claim 2, wherein the concentration of the potassium hydroxide solution is 0.1-0.5 wt%; the volume ratio of the potassium hydroxide solution to the hydrogen peroxide is 1: (10-15).
4. The method according to claim 1, wherein the drying temperature in step (2) is 80-85 ℃.
5. The method according to claim 1, wherein the protective film in step (3) is a silicon nitride film.
6. The method as claimed in claim 1, wherein the step (6) is performed by preparing a silicon wafer weight reducing solution, placing the silicon wafer in the weight reducing solution, and performing alkali polishing at 60-65 ℃ for 145 seconds to reduce the weight of the silicon wafer in the production line by 0.11-0.13 g.
7. The method as claimed in claim 1 or 6, wherein the silicon wafer weight reducing solution is prepared by mixing potassium hydroxide solution and additive.
8. The method of claim 7, wherein the concentration of the potassium hydroxide solution is 0.1-0.5 wt%; the volume ratio of the potassium hydroxide solution to the additive is (5-8): 1; the additive is Tuobang BP 63.
9. The method for reducing silicon wafer in-line cost and increasing open pressure as claimed in claim 1, wherein the material used for the aluminum oxide film in step (8) is trimethylaluminum.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210037850.3A CN114420776A (en) | 2022-01-13 | 2022-01-13 | Method for reducing cost of silicon wafer production line and improving open-circuit pressure |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210037850.3A CN114420776A (en) | 2022-01-13 | 2022-01-13 | Method for reducing cost of silicon wafer production line and improving open-circuit pressure |
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