CN117080306A - Large-size battery texturing equipment and method - Google Patents
Large-size battery texturing equipment and method Download PDFInfo
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- CN117080306A CN117080306A CN202311120260.8A CN202311120260A CN117080306A CN 117080306 A CN117080306 A CN 117080306A CN 202311120260 A CN202311120260 A CN 202311120260A CN 117080306 A CN117080306 A CN 117080306A
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- 238000000034 method Methods 0.000 title claims abstract description 49
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 244
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 244
- 239000010703 silicon Substances 0.000 claims abstract description 244
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 222
- 239000007788 liquid Substances 0.000 claims abstract description 142
- 238000005406 washing Methods 0.000 claims abstract description 133
- 238000004140 cleaning Methods 0.000 claims abstract description 92
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims abstract description 80
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 74
- 239000003814 drug Substances 0.000 claims abstract description 71
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims abstract description 65
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 59
- 230000003647 oxidation Effects 0.000 claims abstract description 53
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 53
- 239000002253 acid Substances 0.000 claims abstract description 46
- 238000001035 drying Methods 0.000 claims abstract description 45
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 38
- 238000005498 polishing Methods 0.000 claims abstract description 31
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 29
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 28
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims abstract description 25
- 239000000654 additive Substances 0.000 claims abstract description 21
- 239000011259 mixed solution Substances 0.000 claims abstract description 19
- 230000000996 additive effect Effects 0.000 claims abstract description 17
- 238000002360 preparation method Methods 0.000 claims abstract description 12
- 230000001590 oxidative effect Effects 0.000 claims abstract description 5
- 238000005554 pickling Methods 0.000 claims description 76
- 239000000243 solution Substances 0.000 claims description 44
- 239000012535 impurity Substances 0.000 claims description 21
- 229910052751 metal Inorganic materials 0.000 claims description 18
- 239000002184 metal Substances 0.000 claims description 18
- 238000007599 discharging Methods 0.000 claims description 7
- 238000005520 cutting process Methods 0.000 claims description 5
- 230000005587 bubbling Effects 0.000 claims description 2
- 210000002268 wool Anatomy 0.000 abstract description 5
- 235000012431 wafers Nutrition 0.000 description 193
- 230000001502 supplementing effect Effects 0.000 description 48
- 239000010410 layer Substances 0.000 description 44
- 238000002156 mixing Methods 0.000 description 19
- 238000006243 chemical reaction Methods 0.000 description 15
- 230000007797 corrosion Effects 0.000 description 13
- 238000005260 corrosion Methods 0.000 description 13
- 239000000203 mixture Substances 0.000 description 13
- 238000002310 reflectometry Methods 0.000 description 13
- 230000003749 cleanliness Effects 0.000 description 11
- 230000000694 effects Effects 0.000 description 9
- 229910021645 metal ion Inorganic materials 0.000 description 8
- 239000007789 gas Substances 0.000 description 6
- 239000002351 wastewater Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 239000003921 oil Substances 0.000 description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- 230000004075 alteration Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
- 238000007517 polishing process Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 239000012670 alkaline solution Substances 0.000 description 2
- 229910021419 crystalline silicon Inorganic materials 0.000 description 2
- 238000001000 micrograph Methods 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- VMHLLURERBWHNL-UHFFFAOYSA-M Sodium acetate Chemical compound [Na+].CC([O-])=O VMHLLURERBWHNL-UHFFFAOYSA-M 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 238000010668 complexation reaction Methods 0.000 description 1
- 239000008139 complexing agent Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 239000013530 defoamer Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 235000013312 flour Nutrition 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000001632 sodium acetate Substances 0.000 description 1
- 235000017281 sodium acetate Nutrition 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 238000010301 surface-oxidation reaction Methods 0.000 description 1
Classifications
-
- 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
-
- 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
- H01L21/02057—Cleaning during device manufacture
-
- 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
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67017—Apparatus for fluid treatment
- H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
- H01L21/6704—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing
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- 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
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67155—Apparatus for manufacturing or treating in a plurality of work-stations
- H01L21/67161—Apparatus for manufacturing or treating in a plurality of work-stations characterized by the layout of the process chambers
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- 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
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67155—Apparatus for manufacturing or treating in a plurality of work-stations
- H01L21/67207—Apparatus for manufacturing or treating in a plurality of work-stations comprising a chamber adapted to a particular process
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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
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- 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)
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Abstract
The application discloses a large-size battery texturing device and a method, wherein the device comprises the following steps: the oxidation unit is used for oxidizing the silicon wafer by adopting ozone to obtain a silicon dioxide oxide layer; the first acid washing unit is used for washing a silicon dioxide oxide layer on the silicon wafer by adopting hydrofluoric acid liquid medicine; the pretreatment unit is used for performing rough polishing and pre-cleaning on the silicon wafer by adopting sodium hydroxide liquid medicine; the texturing unit is used for texturing the silicon wafer by adopting mixed liquor of sodium hydroxide, additive and water; the post-treatment unit is used for cleaning the silicon wafer after texturing by adopting a mixed solution of hydrogen peroxide and sodium hydroxide; the second acid washing unit is used for carrying out acid washing on the silicon wafer subjected to the wool making by adopting a mixed solution of hydrofluoric acid and hydrochloric acid; the drying unit is used for drying the pickled silicon wafer to finish the preparation. The texturing method can obtain the silicon wafer with uniform microstructure, and greatly improves the conductivity of the battery.
Description
Technical Field
The application belongs to the technical field of manufacturing of crystalline silicon solar cells, and particularly relates to large-size battery texturing equipment and a method.
Background
The solar photovoltaic cell texturing process is to remove a mechanical damage layer on the surface of a silicon wafer by alkali corrosion, form pyramid-shaped textured surfaces, reduce the reflection of light on the surface of the silicon wafer, improve the absorption of the silicon wafer to light, and further improve the photoelectric conversion efficiency of the solar cell. Along with the development of the photovoltaic market, the requirements of high power and high conversion rate are met while the production cost of the solar cell module is reduced, so that the small-size silicon wafer used by the current shingled cell is eliminated gradually due to the small effective area and low cell conversion power. The prior art is to directly pretreat the silicon wafer and then texture-making, post-treatment, acid washing and drying, but the increase of the size of the silicon wafer of the laminated tile battery leads to the occurrence of more metal impurities and greasy dirt in the cutting process of the silicon wafer, the residual impurities on the surface of the large-size silicon wafer can not be completely removed according to the prior texture-making process, the surface of the silicon wafer is easy to generate dirt or spots after texture-making, the conductivity of the battery is seriously affected, the conversion efficiency of the battery is low, the power of components is low, and the product quality can not be ensured.
Therefore, it is needed to provide a large-size battery texturing method, which solves the technical problem of low battery electrical performance caused by unclean removal of oil stains and metal impurities on the surface of a silicon wafer in the texturing process in the prior art.
Disclosure of Invention
The application aims to provide a large-size battery texturing method, which is particularly suitable for texturing square silicon wafers with the size of 160-260mm, and aims to solve the technical problem of low battery electrical performance caused by unclean removal of greasy dirt and metal impurities on the surface of the silicon wafers in the texturing process in the prior art and improve the surface cleanliness of the silicon wafers.
In order to achieve the above purpose, the application provides a large-size battery texturing device, which sequentially comprises an oxidation unit, a first acid washing unit, a pretreatment unit, a texturing unit, a post-treatment unit, a second acid washing unit and a drying unit;
the oxidation unit is used for oxidizing the silicon wafer by adopting ozone to obtain a silicon dioxide oxide layer;
the first acid washing unit is used for washing a silicon dioxide oxide layer on the silicon wafer by adopting hydrofluoric acid liquid medicine;
the pretreatment unit is used for performing rough polishing and pre-cleaning on the silicon wafer by adopting sodium hydroxide liquid medicine;
the texturing unit is used for texturing the silicon wafer by adopting mixed liquor of sodium hydroxide, an additive and water;
the post-treatment unit is used for cleaning the silicon wafer after texturing by adopting a mixed solution of hydrogen peroxide and sodium hydroxide;
the second pickling unit is used for pickling the silicon wafer subjected to texturing by adopting a mixed solution of hydrofluoric acid and hydrochloric acid;
and the drying unit is used for drying the pickled silicon wafer to finish the preparation.
Optionally, the oxidation unit comprises a feeding tank and an oxidation tank;
the feeding groove is used for bubbling cleaning the silicon wafer by pure water;
the oxidation tank is used for removing metal impurities on the silicon wafer by adopting sodium hydroxide liquor with the solution ratio of 3-4%, and introducing ozone to oxidize the silicon wafer at the temperature of 40-80 ℃ for 1-5min to obtain the silicon dioxide oxide layer.
Optionally, the first acid washing unit comprises a first acid washing tank, and the first acid washing tank is used for washing the silicon dioxide oxide layer on the silicon wafer for 1-5min by adopting hydrofluoric acid liquid medicine with the solution ratio of 10-15%.
Optionally, the pretreatment unit comprises a rough polishing tank and a pre-cleaning tank;
the rough polishing groove is used for rough polishing the silicon wafer at the temperature of 60-100 ℃ by adopting sodium hydroxide liquid medicine with the solution ratio of 4-4.5%, and removing a cutting damage layer;
the pre-cleaning tank is used for cleaning the silicon wafer for 1-5min at the temperature of 40-80 ℃ by adopting a mixed solution of hydrogen peroxide with the solution ratio of 4-7% and sodium hydroxide with the solution ratio of 0.2-0.5%.
Optionally, the texturing unit comprises a texturing groove, wherein the texturing groove is used for texturing the silicon wafer for 3.5-9.5min at the temperature of 60-100 ℃ by adopting mixed liquid medicine of sodium hydroxide, an additive and water to obtain textured surfaces; wherein the solution ratio of the sodium hydroxide is 4-4.5%, and the solution ratio of the additive is 0.6-1%.
Optionally, the post-treatment unit comprises a post-cleaning tank, wherein the post-cleaning tank is used for cleaning the silicon wafer for 1-5min at the temperature of 40-80 ℃ by adopting a mixed solution of hydrogen peroxide with the solution ratio of 4-7% and sodium hydroxide with the solution ratio of 0.2-0.5%.
Optionally, the second pickling unit comprises a second pickling tank, and the second pickling tank is used for pickling the silicon wafer at normal temperature by adopting a mixed solution of hydrofluoric acid with a solution ratio of 10-15% and hydrochloric acid with a solution ratio of 10-15%.
Optionally, the last steps of the oxidation unit, the first pickling unit, the pretreatment unit, the texturing unit, the post-treatment unit and the second pickling unit are respectively provided with a first washing tank, a second washing tank, a third washing tank, a fourth washing tank, a fifth washing tank and a sixth washing tank, which are all used for cleaning the silicon wafer by pure water for 0.5-3.5min.
Optionally, the drying unit comprises a full lifting groove, a drying groove and a blanking groove;
the full lifting groove is used for cleaning the silicon wafer for 0.5-3.5min by adopting hot water at 50-90 ℃;
the drying tank is used for drying the silicon wafer for 4-8min at the temperature of 60-100 ℃;
the blanking groove is used for receiving the silicon wafer after texturing.
The application also provides a large-size battery texturing method, which comprises the following steps:
placing the silicon wafer in sodium hydroxide liquor with the solution ratio of 3-4%, and introducing ozone to oxidize the silicon wafer at the temperature of 40-80 ℃ for 1-5min to obtain a silicon dioxide oxide layer;
cleaning a silicon dioxide oxide layer on a silicon wafer for 1-5min by adopting hydrofluoric acid liquid medicine with the solution ratio of 10-15%;
coarse polishing the silicon wafer at 60-100deg.C by adopting sodium hydroxide solution with solution ratio of 4-4.5%;
after cleaning the roughly polished silicon wafer, adopting mixed liquor of sodium hydroxide, additives and water to texture the silicon wafer for 3.5-9.5min at the temperature of 60-100 ℃;
cleaning the silicon wafer after texturing, and then pickling the silicon wafer at normal temperature by adopting a mixed solution of hydrofluoric acid with the solution ratio of 10-15% and hydrochloric acid with the solution ratio of 10-15%;
and drying the pickled silicon wafer to finish the preparation.
The application has the technical effects that:
according to the application, metal impurities on the surface of the silicon wafer are oxidized in advance to form an oxide layer which is easy to remove, the oxide layer is complexed after the first acid washing to form a water-soluble complex, so that greasy dirt attached to the oxide layer can be effectively removed, the surface cleanliness of the silicon wafer is improved, a good surface foundation is provided for the subsequent preparation of the textured surface, and the silicon wafer with uniform microstructure can be obtained after the pretreatment, texturing, post-treatment, second acid washing and drying in sequence, so that the conductivity of a battery is greatly improved;
the application is provided with the washing tanks after oxidation, first acid washing, pretreatment, texturing, post treatment and second acid washing, and aims to remove the liquid medicine on the surface layer of the silicon wafer, and simultaneously remove the residual organic solvent and metal ions on the surface of the silicon wafer, thereby being beneficial to removing the residual metal impurities on the surface of the silicon wafer, improving the cleanliness of the surface of the silicon wafer and further being beneficial to improving the conductivity of the battery.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:
FIG. 1 is a schematic diagram of a large-size battery texturing apparatus according to an embodiment of the present application;
wherein, 1, feeding groove; 2. an oxidation tank; 3. a first washing tank; 4. a first pickling tank; 5. a second washing tank; 6. rough polishing grooves; 7. pre-cleaning the tank; 8. a third washing tank; 9. a texturing groove; 10. a fourth washing tank; 11. a rear cleaning tank; 12. a fifth washing tank; 13. a second pickling tank; 14. a sixth water washing tank; 15. full lifting groove; 16. a drying tank; 17. and discharging the material.
Detailed Description
It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.
It should be noted that the steps illustrated in the flowcharts of the figures may be performed in a computer system such as a set of computer executable instructions, and that although a logical order is illustrated in the flowcharts, in some cases the steps illustrated or described may be performed in an order other than that illustrated herein.
Example 1
As shown in fig. 1, in this embodiment, a large-size battery wool making apparatus and a method are provided, where the wool making apparatus sequentially includes an oxidation unit, a first pickling unit, a pretreatment unit, a wool making unit, a post-treatment unit, a second pickling unit, and a drying unit, and after the oxidation unit, the first pickling unit, the pretreatment unit, the wool making unit, the post-treatment unit, and the second pickling unit, an independent rinsing tank is respectively provided.
Specifically, the oxidation unit includes material loading groove 1, oxidation groove 2 and first washing groove 3 in proper order, and the material loading groove 1 is provided with the pure water, carries out normal atmospheric temperature to the silicon chip that gets into in the material loading groove 1 earlier and washs, and material loading groove 1 is the bubble washing, and the purpose is washd and gets rid of large granule impurity and silica flour dust on the silicon chip surface earlier. The silicon wafer from the feeding groove 1 enters an oxidation groove 2, mixed liquor of sodium hydroxide and water is placed in the oxidation groove 2, ozone gas is simultaneously introduced into the oxidation groove 2, and the ozone can react with silicon on the outermost layers on the two lateral surfaces of the silicon wafer to generate a silicon dioxide oxide layer, and the silicon dioxide layer is formedThe silicon oxide layer forms a water-soluble complex H when exposed to hydrofluoric acid 2 SiF 6 . In the prior art, hydrogen peroxide is commonly used for oxidizing silicon, but the hydrogen peroxide is easy to volatilize, the reaction between the hydrogen peroxide and silicon is not easy to control, and the concentration of hydrogen peroxide solution in a groove needs to be always monitored during oxidation to prevent excessive volatilization, so that the silicon wafer is not oxidized sufficiently; and the hydrogen peroxide is directly discharged after being used to pollute the environment and is not easy to recycle. The flow of the ozone can be controlled by adopting the ozone, compared with hydrogen peroxide, the reaction speed of the ozone and silicon is slower, and the ozone can be fully oxidized; meanwhile, ozone is lower than the production cost of hydrogen peroxide and is also environment-friendly, so that the embodiment prefers ozone oxidation to replace hydrogen peroxide. In the oxidation process, the ozone amount needs to be periodically supplemented to ensure that the surface of the silicon wafer is fully oxidized, so that the surface oxidation effect of the silicon wafer is consistent, and the liquid supplementing amount of the ozone is 5-25L/h. In the liquid medicine in the oxidation tank 2, sodium hydroxide liquid medicine is used for removing metal impurities on the surface of a silicon wafer, the solution ratio of sodium hydroxide is 3-4%, and the balance is pure water; the oxidation temperature is 40-80 ℃ and the oxidation time is 1-5min. Along with the increase of the silicon wafer size, the whole volume of the liquid medicine required in each step and the liquid distribution ratio of each component are correspondingly improved in the texturing process so as to ensure the texturing effect of the silicon wafer. In the embodiment, after each 400-600 frames of silicon wafers are produced, the liquid medicine is supplemented in a rotating way, wherein 200-400 silicon wafers are stored in each frame, the number of the silicon wafers which are carried in each frame is the same, and the process is not repeated. In order to ensure the consistency of the concentration of the liquid medicine in the tank and the effect of oxidation quality, the liquid supplementing amount of sodium hydroxide in each round is 0.05-0.15L. The oxidation unit oxidizes the silicon on the outer surface of the double layers of the silicon wafer through ozone gas to form a silicon dioxide oxidation layer which is easy to remove, and other surface impurities or greasy dirt attached to the oxidation layer can be cleaned by subsequent pickling, so that the cleaning of metal impurities on the surface of the silicon wafer is accelerated, the cleanliness of the surface of the silicon wafer can be ensured to the greatest extent, and a clean plane foundation is laid for subsequent texturing in advance.
The first water washing tank 3 is arranged behind the oxidation tank 2, pure water is stored in the first water washing tank 3, the cleaning time is 0.5-3.5min, water is stored in the first water washing tank 3 for supplementing regularly and uninterruptedly, the purpose is to remove the liquid medicine on the surface of the oxidized silicon wafer, and meanwhile, the metal impurities and greasy dirt on the surface of the silicon wafer can be cleaned.
Further, the first acid washing unit comprises a first acid washing tank 4 and a second acid washing tank 5, the liquid medicine is mixed solution of hydrofluoric acid and pure water, wherein the proportion of the prepared solution of the hydrofluoric acid is 10-15%, the first acid washing unit is carried out at normal temperature, and the acid washing time is 1-5min. In the process, hydrofluoric acid can carry out complexation reaction with silicon dioxide on an oxide layer on the surface of a silicon wafer, and the specific reaction formula is as follows:
6HF+SiO 2 ＝H 2 SiF 6 +2H 2 O
H 2 SiF 6 is a complex easy to dissolve in water, can completely remove the silicon dioxide of an oxide layer and oil stains attached on the silicon dioxide oxide layer after being washed by the first pickling tank 4, can improve the surface cleanliness of a silicon wafer, and provides a good surface foundation for the subsequent preparation of suede. In the unit, in order to ensure the consistency of the concentration of hydrofluoric acid in the liquid medicine of the first pickling tank 4, the liquid medicine is supplemented once after each 400-600 frames of silicon wafers are produced, the liquid supplementing amount of the hydrofluoric acid in each round is 0.3-0.7L, and the oxide layer can be removed without using other acid liquor. The pickled silicon wafer needs to enter the second washing tank 5 for washing so as to remove the pickling liquid medicine on the surface of the silicon wafer, and meanwhile, the residual metal impurities and greasy dirt on the surface of the silicon wafer can be removed, so that the surface cleaning of the silicon wafer is further ensured.
In the prior art, the mixed solution of nitric acid and hydrofluoric acid is used for directly pickling the surface of the silicon wafer after being fed, because silicon, nitric acid and hydrofluoric acid do not react independently, but when silicon, nitric acid and hydrofluoric acid are simultaneously in phase, the reaction is severe, the corrosion speed is high, the corrosion effect is not well controlled, the proportion of the two acids is not well regulated and controlled, the cleaning effect obtained by directly mixing is not good, and oil stains and metal impurities cannot be completely removed. The application removes metal impurity and greasy dirt on the surface of silicon slice in steps, firstly forms a layer of oxide layer silicon dioxide on the surface of silicon slice by using unusual ozone gas, then washes the liquid medicine on the oxide layer by water, then reacts the silicon dioxide by hydrofluoric acid to form a water-soluble silicon dioxideComplex H of (2) 2 SiF 6 So that the oxide layer on the surface of the silicon wafer and the greasy dirt attached to the surface of the oxide layer are removed by one pass, and discharged along with water; and the silicon wafer surface is cleaned independently through the second washing tank 5 which is independently arranged after the oxidation and the first acid washing, so that the residual metal impurities and greasy dirt on the silicon wafer surface can be completely removed, the cleaning effect of the silicon wafer surface is better, and the subsequent texturing is more facilitated. The spectral ellipsometer with model M-2000V is used for testing that the depth of a silicon dioxide layer in the surface of a silicon wafer is 1-2um, namely the thickness of a single layer thinned after the first acid washing is 1-2um, and the method is completely controllable and meets the requirements.
The pretreatment unit comprises a rough polishing groove 6, a pre-cleaning groove 7 and a third water-cleaning groove 8, wherein mixed liquor of sodium hydroxide and pure water is placed in the rough polishing groove 6, so that a cutting damage layer on the surface of a silicon wafer is removed, and a double-sided flat surface is formed after corrosion thinning, thereby being beneficial to the subsequent preparation of a suede; meanwhile, a small amount of metal ions and organic matters remained on the surface of the silicon wafer can be removed. In the unit, the liquid medicine in the rough polishing groove 6 is sodium hydroxide with the solution ratio of 4-4.5%, the rough polishing temperature is 60-100 ℃, and after 1-5min, the rough polishing of the silicon wafer can be finished, and the damaged layer on the surface of the silicon wafer is removed. In order to ensure the rough polishing effect, the chemical liquid is supplemented once after each 400-600 frames of silicon wafers are produced, and the liquid supplementing amount of sodium hydroxide in each round is 0.4-1.2L. The liquid medicine in the pre-cleaning tank 7 is a mixed solution of hydrogen peroxide and sodium hydroxide, the solution ratio of the hydrogen peroxide to the sodium hydroxide is 4-7% and 0.2-0.5%, the cleaning temperature is 40-80 ℃ and the cleaning time is 1-5min. The alkaline solution is used for cleaning metal ions and organic matters on the silicon wafer in advance, so that the cleanliness of the silicon wafer entering the texturing groove 9 is ensured, the concentration stability of the liquid medicine in the pre-cleaning groove 7 is ensured, the liquid medicine is supplemented once in turn after each 400-600 frames of silicon wafers are produced, and the liquid supplementing amounts of hydrogen peroxide and sodium hydroxide in each turn are respectively 0.5-1.5L and 0.05-0.15L. And after the pre-cleaning is finished, the liquid medicine enters the third washing tank 8 to clean the surface of the silicon wafer. Since the rough polishing tank 6 and the pre-cleaning tank 7 both contain alkali, the cleaning of the water-washing tank is not required to be arranged behind the rough polishing tank 6, and the third water-washing tank 8 is only required to be arranged behind the pre-cleaning tank 7.
The texturing unit comprises a texturing groove 9 and a fourth washing groove 10, wherein mixed liquor of sodium hydroxide, partial additive and water is placed in the texturing groove 9, the solution ratio of the sodium hydroxide is 4-4.5%, the additive comprises water, sodium acetate, defoamer and surfactant, the solution ratio of the additive is 0.6-1%, and after the silicon wafer is textured for 3.5-9.5min at the texturing temperature of 60-100 ℃, a plurality of densely distributed concave-convex surface tissue structures can be formed on the surface of the silicon wafer by corrosion. The sodium hydroxide with the solution ratio of 4-4.5% is selected, so that the anisotropic corrosion characteristics of crystalline silicon with different corrosion rates in different crystal orientations can be realized, a pyramid-shaped suede which is uniform in size and is fully distributed on the whole silicon surface can be formed on the surface of the silicon wafer, the refraction times of sunlight on the surface of the battery piece are increased, the absorption of the battery piece to light is improved, the reflection is reduced, the short-circuit current is further improved, and finally the photoelectric conversion efficiency of the battery is improved. The texturing effect is mainly related to the texturing temperature, the uniformity of the concentration of the liquid medicine and the flowability of the liquid medicine. In this embodiment, preferably, the temperature of the texturing is 70-90 ℃ to ensure the fluidity of the liquid medicine, and meanwhile, the liquid medicine needs to be timely replenished, specifically, the concentration of the liquid medicine is diluted and the liquid ratio is affected because the texturing time is longer and the liquid preparation ratio of the texturing liquid medicine is required to be higher, so that the liquid medicine needs to be replenished once after 200-300 frames of silicon wafers are produced to ensure the consistency and uniformity of the liquid medicine concentration, the liquid replenishment amount of sodium hydroxide in each round is 0.5-1.5L, and the liquid replenishment amount of the additive is 0.05-0.15L. And (5) cleaning the textured silicon wafer in a fourth water washing tank 10 to remove alkaline liquid medicine on the surface of the silicon wafer.
The post-treatment unit comprises a post-cleaning tank 11 and a fifth water-cleaning tank 12, the liquid medicine placed in the post-cleaning tank 11 is a mixed solution of hydrogen peroxide and sodium hydroxide, the solution ratio of the hydrogen peroxide to the sodium hydroxide is 4-7% and 0.2-0.5%, the cleaning temperature is 40-80 ℃, and the cleaning time is 1-5min. The alkaline solution is used for removing the residual additives and organic matters on the surface of the silicon wafer, and enters the fifth water washing tank 12 to wash the liquid medicine on the surface of the silicon wafer after the cleaning is finished, so that the cleanliness of the surface of the silicon wafer is improved. In order to ensure the stability of the concentration of the liquid medicine in the post-cleaning tank 11, the liquid medicine is supplemented once after each 400-600 frames of silicon wafers are produced, and the liquid supplementing amounts of hydrogen peroxide and sodium hydroxide in each round are respectively 0.5-1.5L and 0.05-0.15L.
The second pickling unit comprises a second pickling tank 13 and a sixth pickling tank 14, wherein the second pickling tank 13 is placed with a mixed solution of hydrofluoric acid and hydrochloric acid, the solution ratio of the hydrofluoric acid is 10-15%, and the solution ratio of the hydrochloric acid is 10-15%. The hydrofluoric acid can remove an oxide layer on the surface of the silicon, the hydrochloric acid can remove metal impurities remained on the surface of the silicon wafer, and the hydrochloric acid has the dual functions of acid and complexing agent, and chloride ions in the hydrochloric acid can dissolve other metal ions stained on the surface of the silicon wafer. In the second pickling process, pickling is carried out at normal temperature for 1-5min, and in order to ensure the stability of pickling liquid medicine in the tank, the liquid medicine is supplemented once after each 400-600 frames of silicon wafers are produced, the liquid medicine supplementing amount of hydrofluoric acid in each round is 0.3-0.9L, and the liquid medicine supplementing amount of hydrochloric acid is as follows: 0.3-0.9L. The purpose of acid washing is to remove silicon dioxide and metal ions on the surface of the silicon wafer, so as to form a suede with better hydrophobicity. And after pickling, cleaning the silicon wafer by a sixth washing tank 14 to remove the liquid medicine on the surface of the silicon wafer.
The drying unit comprises a full lifting groove 15, a drying groove 16 and a discharging groove 17, hot water is placed in the full lifting groove 15, the temperature is 50-90 ℃, preferably 70-90 ℃, the cleaning time is 0.5-3.5min, and the aim of cleaning the surface of the silicon wafer is to reduce water marks on the surface, so that the subsequent drying treatment is facilitated. The silicon wafer is fully lifted and then enters the drying groove 16, the drying temperature is 60-100 ℃, preferably 70-90 ℃, the drying time is 4-8min, and hot air is used for drying water on the surface of the silicon wafer, so that the cleanliness of the surface of the silicon wafer is ensured.
In this embodiment, the first, second, third, fourth, fifth and sixth washing tanks 3, 5, 8, 10, 12 and 14 are all pure water at normal temperature, and the washing time is 0.5 to 3.5min.
According to the embodiment, the metal impurities on the surface of the silicon wafer are oxidized in advance to form the oxide layer which is easy to remove, the oxide layer is complexed after the first acid washing to form a water-soluble complex, oil stains attached to the oxide layer can be effectively removed, the surface cleanliness of the silicon wafer is improved, a good surface foundation is provided for the subsequent preparation of the textured surface, the microstructure of the battery surface of the silicon wafer is more uniform, and the silicon dioxide layer depth of the silicon wafer after the first acid washing, namely the single-sided thinning depth, is 1-2um, and is completely controllable. And simultaneously, after the first pickling, the pretreatment, the texturing, the post-treatment, the second pickling and the drying are sequentially carried out, so that the silicon wafer with the total weight of 0.45-1.45g and uniform microstructure of the single-piece thinning can be obtained, and the conductivity of the battery is improved by 0.01-0.03%.
Example two
The pile making process of the laminated tile battery with the size of 160mm specifically comprises the following steps:
s1: oxidation
The silicon wafer enters an oxidation tank 2 from a feeding tank 1, ozone gas is synchronously introduced, and the liquid medicine of the oxidation tank 2, namely the mixed liquid of 4L of sodium hydroxide and 220L of water, is arranged in advance, wherein the oxidation temperature is 60 ℃, and the oxidation time is 3min. In the oxidation process, after 500 frames are produced, liquid is supplemented once, 200 silicon wafers are loaded in each frame, the number of the silicon wafers loaded in each frame is the same, and the process is not repeated; the ozone make-up amount was 10L/h, and the sodium hydroxide make-up amount was 0.1L. And the oxidized silicon wafer enters the first washing tank 3 again for washing for 2min.
S2: first acid washing
The silicon wafer enters the first pickling tank 4 from the first pickling tank 3 for pickling, wherein the liquid medicine in the first pickling tank 4 is formed by mixing 40L of hydrofluoric acid and 260L of water, and pickling is carried out for 3min at normal temperature. In the first pickling process, the liquid is supplemented once after 500 frames are produced, and the liquid supplementing amount of hydrofluoric acid is 0.5L. And after pickling, cleaning in a second water washing tank 5 for 2min.
S3: pretreatment of
The silicon wafer enters a rough polishing groove 6 from a second washing groove 5 for corrosion, the liquid medicine in the rough polishing groove 6 is formed by mixing 7L of sodium hydroxide and 220L of water, and the silicon wafer is subjected to rough polishing corrosion for 3min at the temperature of 80 ℃. In the rough polishing process, the liquid supplementing is alternated after 500 frames are produced, and the liquid supplementing amount of sodium hydroxide is 0.5L. Then the mixture enters a pre-cleaning tank 7 for cleaning, the liquid medicine in the pre-cleaning tank 7 is formed by mixing 4L of sodium hydroxide, 12L of hydrogen peroxide and 220L of water, and the mixture is cleaned for 2min at the temperature of 60 ℃. In the pre-cleaning process, after 500 frames are produced, the liquid is supplemented once, the liquid supplementing amount of hydrogen peroxide is 1L, and the liquid supplementing amount of sodium hydroxide is 0.1L. And then enters a third washing tank 8 for washing for 2min.
S4: texturing
The silicon wafer enters a texturing groove 9 from a third washing groove 8 for texturing, the liquid medicine of the texturing groove 9 is formed by mixing 10L of sodium hydroxide, 2L of additive and 230L of water, and texturing is carried out for 6.5min at the temperature of 80 ℃. In the velvet making process, after 250 frames are produced, liquid is supplemented alternately, the liquid supplementing amount of sodium hydroxide is 0.8L, and the liquid supplementing amount of the additive is 0.1L. Then the waste water enters the fourth water washing tank 10 for washing for 2 minutes.
S5: post-treatment
The silicon wafer enters a rear cleaning tank 11 from a fourth cleaning tank 10 for cleaning, the liquid medicine in the rear cleaning tank 11 is formed by mixing 12L of hydrogen peroxide, 4L of sodium hydroxide and 220L of water, and the cleaning is carried out for 1.5min under the condition of 60 ℃. In the post-cleaning process, the liquid is supplemented once after 500 frames are produced, the liquid supplementing amount of hydrogen peroxide is 1L, and the liquid supplementing amount of sodium hydroxide is 0.1L. Then the waste water enters the fifth water washing tank 12 for washing for 2 minutes.
S6: acid washing for the second time
The silicon wafer enters a second pickling tank 13 from the fifth washing tank 12 for pickling, the liquid medicine in the second pickling tank 13 is formed by mixing 20L of hydrofluoric acid, 20L of hydrochloric acid and 130L of water, and the pickling is carried out for 3min at normal temperature. In the second pickling process, the liquid is supplemented once after 500 frames are produced, the liquid supplementing amount of hydrofluoric acid is 0.3L, and the liquid supplementing amount of hydrochloric acid is 0.3L. And then enters the sixth water washing tank 14 to be washed for 2min.
S7: drying
The silicon wafer enters a full lifting groove 15 from a sixth washing groove 14 for washing, the temperature of hot water in the full lifting groove 15 is 70 ℃, and the washing is carried out for 2min; then the mixture enters a drying tank 16 for drying, and the mixture is dried for 6 minutes at the temperature of 80 ℃; and then enters the discharging groove 17 to come out.
And (5) checking performance parameters and appearance of the textured silicon wafer. The weight of the silicon wafer before and after the texturing is tested on an electronic balance instrument, the double-sided thinning weight of the silicon wafer is calculated, and the model of the electronic balance is FA124; and the reflectivity of the silicon wafer after texturing is detected by using a D8 reflectivity tester, and the reflectivity is the same as follows. As shown in table 1, compared with the standard requirement, the double-sided thinning weight and the center point reflectivity of the silicon wafer obtained in the present embodiment are 0.53g, and the center point reflectivity is: 7.8 percent, which are smaller than the standard requirement. Table 2 shows that the conversion efficiency of 160mm silicon wafer made according to the present texturing process is improved by 0.03% compared with 160mm silicon wafer made by conventional process, by comparing the electrical parameters of the textured silicon wafer of the present example with those of the textured silicon wafer of the prior art. By observing the microscopic morphology of the silicon wafer subjected to texturing under a scanning electron microscope of 3000 times, a layer of texture surface which is tiny in structure, uniform in size and full of the whole silicon surface is formed on the surface of the silicon wafer, and the appearance of the silicon wafer is complete, and has no obvious chromatic aberration, dirt, spots or cracks. The uniform raised surface can increase the refraction times of light on the surface of the solar cell, is favorable for absorbing the light by the cell, improves the reflectivity of the reduced light, improves the short-circuit current and finally improves the photoelectric conversion efficiency of the cell.
TABLE 1
| Reduced weight/g | Center point reflectivity/% | |
| Standard requirements | 0.55±0.05 | ＜9 |
| Example two | 0.53 | 7.8 |
TABLE 2
| Open circuit voltage/v | Short-circuit current/a | Fill factor | Conversion efficiency/% | |
| Prior Art | 0.6827 | 10.0038 | 78.77 | 22.02 |
| Example two | 0.6833 | 10.0029 | 78.81 | 22.05 |
Example III
The pile making process of the laminated tile battery with the size of 200mm specifically comprises the following steps:
s1: oxidation
The silicon wafer enters an oxidation tank 2 from a feeding tank 1, ozone gas is synchronously introduced, and the liquid medicine of the oxidation tank 2, namely the mixed liquid of 6L of sodium hydroxide and 240L of water, is arranged in advance, wherein the oxidation temperature is 60 ℃, and the oxidation time is 3min. In the oxidation process, the liquid supplementing is alternated after 500 frames are produced, the liquid supplementing amount of ozone is 15L/h, and the liquid supplementing amount of sodium hydroxide is 0.15L. And the oxidized silicon wafer enters the first washing tank 3 again for washing for 2min.
S2: first acid washing
The silicon wafer enters a first pickling tank 4 from a first pickling tank 3 for pickling, wherein the liquid medicine in the first pickling tank 4 is formed by mixing 50L of hydrofluoric acid and 280L of water, and pickling is carried out for 3min at normal temperature. In the first pickling process, the liquid is supplemented once after 500 frames are produced, and the liquid supplementing amount of hydrofluoric acid is 0.8L. And after pickling, cleaning in a second water washing tank 5 for 2min.
S3: pretreatment of
The silicon wafer enters a rough polishing groove 6 from a second washing groove 5 for corrosion, the liquid medicine in the rough polishing groove 6 is formed by mixing 9L of sodium hydroxide and 240L of water, and the silicon wafer is subjected to rough polishing corrosion for 3min at the temperature of 80 ℃. In the rough polishing process, the liquid supplementing is alternated after 500 frames are produced, and the liquid supplementing amount of sodium hydroxide is 0.8L. Then the mixture enters a pre-cleaning tank 7 for cleaning, the liquid medicine in the pre-cleaning tank 7 is formed by mixing 6L of sodium hydroxide, 14L of hydrogen peroxide and 240L of water, and the mixture is cleaned for 2min at the temperature of 60 ℃. In the pre-cleaning process, the liquid is supplemented once after 500 frames are produced, the liquid supplementing amount of hydrogen peroxide is 1.5L, and the liquid supplementing amount of sodium hydroxide is 0.15L. And then enters a third washing tank 8 for washing for 2min.
S4: texturing
The silicon wafer enters a texturing groove 9 from a third washing groove 8 for texturing, the liquid medicine of the texturing groove 9 is formed by mixing 12L of sodium hydroxide, 3L of additive and 250L of water, and texturing is carried out for 6.5min at the temperature of 80 ℃. In the velvet making process, after 250 frames are produced, liquid is supplemented alternately, the liquid supplementing amount of sodium hydroxide is 1.2L, and the liquid supplementing amount of the additive is 0.15L. Then the waste water enters the fourth water washing tank 10 for washing for 2 minutes.
S5: post-treatment
The silicon wafer enters a post-cleaning tank 11 from a fourth cleaning tank 10 for cleaning, the liquid medicine in the post-cleaning tank 11 is formed by mixing 14L of hydrogen peroxide, 6L of sodium hydroxide and 240L of water, and the silicon wafer is cleaned for 1.5min at the temperature of 60 ℃. In the post-cleaning process, the liquid is supplemented once after 500 frames are produced, the liquid supplementing amount of hydrogen peroxide is 1.5L, and the liquid supplementing amount of sodium hydroxide is 0.15L. Then the waste water enters the fifth water washing tank 12 for washing for 2 minutes.
S6: acid washing for the second time
The silicon wafer enters a second pickling tank 13 from the fifth pickling tank 12 for pickling, the liquid medicine in the second pickling tank 13 is formed by mixing 30L of hydrofluoric acid, 30L of hydrochloric acid and 150L of water, and the pickling is carried out for 3min at normal temperature. In the second pickling process, the liquid is supplemented once after 500 frames are produced, the liquid supplementing amount of hydrofluoric acid is 0.6L, and the liquid supplementing amount of hydrochloric acid is 0.6L. And then enters the sixth water washing tank 14 to be washed for 2min.
S7: drying
The silicon wafer enters a full lifting groove 15 from a sixth washing groove 14 for washing, the temperature of hot water in the full lifting groove 15 is 70 ℃, and the washing is carried out for 2min; then the mixture enters a drying tank 16 for drying, and the mixture is dried for 6 minutes at the temperature of 80 ℃; and then enters the discharging groove 17 to come out.
And (5) checking performance parameters and appearance of the textured silicon wafer. As shown in table 3, compared with the standard requirement, the double-sided thinning weight and the center point reflectivity of the silicon wafer obtained in this embodiment are 0.82g, and the center point reflectivity is: 7.8 percent, which are smaller than the standard requirement. Table 4 shows that the conversion efficiency of 200mm silicon wafer made according to the present texturing process is improved by 0.03% compared with that of 200mm silicon wafer made by conventional process, by comparing the electrical parameters of the textured silicon wafer of the present example with those of textured silicon wafer made by the prior art. The microscopic appearance of the silicon wafer after texturing under a scanning electron microscope of 3000 times can be seen, a layer of texture surface which has a tiny structure and uniform size and is distributed on the whole silicon surface is formed on the surface of the silicon wafer, the appearance of the silicon wafer is complete, and obvious chromatic aberration, dirt, spots or cracks are avoided. In this example, both the performance parameters and the microphotographs were acceptable.
TABLE 3 Table 3
| Reduced weight/g | Center point reflectivity/% | |
| Standard requirements | 0.8±0.05 | ＜9 |
| Example III | 0.82 | 7.8 |
TABLE 4 Table 4
| Open circuit voltage/v | Short-circuit current/a | Fill factor | Conversion efficiency/% | |
| Prior Art | 0.6813 | 9.9774 | 78.90 | 21.95 |
| Example III | 0.6820 | 9.9782 | 78.91 | 21.98 |
Example IV
The pile making process of the laminated tile battery with the size of 260mm specifically comprises the following steps:
s1: oxidation
The silicon wafer enters an oxidation tank 2 from a feeding tank 1, ozone gas is synchronously introduced, and the liquid medicine of the oxidation tank 2, namely the mixed liquid of 8L of sodium hydroxide and 260L of water, is arranged in advance, wherein the oxidation temperature is 60 ℃, and the oxidation time is 3min. In the oxidation process, after 500 frames are produced, liquid supplementing is carried out alternately, the liquid supplementing amount of ozone is 20L/h, and the liquid supplementing amount of sodium hydroxide is 0.2L. And the oxidized silicon wafer enters the first washing tank 3 again for washing for 2min.
S2: first acid washing
The silicon wafer enters a first pickling tank 4 from a first pickling tank 3 for pickling, wherein the liquid medicine in the first pickling tank 4 is formed by mixing 70L of hydrofluoric acid and 300L of water, and pickling is carried out for 3min at normal temperature. In the first pickling process, the liquid is supplemented once after 500 frames are produced, and the liquid supplementing amount of hydrofluoric acid is 1.2L. And after pickling, the mixture is fed into a washing tank 5 for washing for 2min.
S3: pretreatment of
The silicon wafer enters a rough polishing groove 6 from a second washing groove 5 for corrosion, the liquid medicine in the rough polishing groove 6 is formed by mixing 12L of sodium hydroxide and 260L of water, and the silicon wafer is subjected to rough polishing corrosion for 3min at the temperature of 80 ℃. In the rough polishing process, the liquid supplementing is alternated after 500 frames are produced, and the liquid supplementing amount of sodium hydroxide is 1.2L. Then the mixture enters a pre-cleaning tank 7 for cleaning, the liquid medicine in the pre-cleaning tank 7 is formed by mixing 8L of sodium hydroxide, 16L of hydrogen peroxide and 260L of water, and the mixture is cleaned for 2min at the temperature of 60 ℃. In the pre-cleaning process, after 500 frames are produced, the liquid is supplemented once, the liquid supplementing amount of hydrogen peroxide is 2L, and the liquid supplementing amount of sodium hydroxide is 0.2L. And then enters a third washing tank 8 for washing for 2min.
S4: texturing
The silicon wafer enters a texturing groove 9 from a third washing groove 8 for texturing, the liquid medicine of the texturing groove 9 is formed by mixing 14L of sodium hydroxide, 4L of additive and 270L of water, and texturing is carried out for 6.5min at the temperature of 80 ℃. In the velvet making process, after 250 frames are produced, liquid is supplemented alternately, the liquid supplementing amount of sodium hydroxide is 1.8L, and the liquid supplementing amount of the additive is 0.2L. Then the waste water enters the fourth water washing tank 10 for washing for 2 minutes.
S5: post-treatment
The silicon wafer enters a rear cleaning tank 11 from a fourth cleaning tank 10 for cleaning, the liquid medicine in the rear cleaning tank 11 is formed by mixing 16L of hydrogen peroxide, 8L of sodium hydroxide and 260L of water, and the cleaning is carried out for 1.5min under the condition of 60 ℃. In the post-cleaning process, the liquid is supplemented once after 500 frames are produced, the liquid supplementing amount of hydrogen peroxide is 2L, and the liquid supplementing amount of sodium hydroxide is 0.2L. Then the waste water enters the fifth water washing tank 12 for washing for 2 minutes.
S6: acid washing for the second time
The silicon wafer enters the second pickling tank 13 from the fifth washing tank 12 for pickling, the liquid medicine in the second pickling tank 13 is formed by mixing 40L of hydrofluoric acid, 40L of hydrochloric acid and 180L of water, and the pickling is carried out for 3min at normal temperature. In the second pickling process, the liquid is supplemented once after 500 frames are produced, the liquid supplementing amount of hydrofluoric acid is 0.9L, and the liquid supplementing amount of hydrochloric acid is 0.9L. And then enters the sixth water washing tank 14 to be washed for 2min.
S7: drying
The silicon wafer enters a full lifting groove 15 from a sixth washing groove 14 for washing, the temperature of hot water in the full lifting groove 15 is 70 ℃, and the washing is carried out for 2min; then the mixture enters a drying tank 16 for drying, and the mixture is dried for 6 minutes at the temperature of 80 ℃; and then enters the discharging groove 17 to come out.
And (5) checking performance parameters and appearance of the textured silicon wafer. As shown in table 5, compared with the standard requirement, the double-sided thinned weight and the center point reflectivity of the silicon wafer obtained in this embodiment are 1.39g, and the center point reflectivity is: 7.8 percent, which are smaller than the standard requirement. Table 6 shows that the conversion efficiency of a 260mm wafer made according to the present texturing process is improved by 0.03% over a 260mm wafer made according to the present texturing process by comparing the electrical parameters of the textured wafer of the present example with those of the textured wafer of the prior art. Observing the microscopic morphology of the silicon wafer after texturing under a scanning electron microscope of 3000 times, forming a layer of texture surface which has a tiny structure and uniform size and is fully distributed on the whole silicon surface on the surface of the silicon wafer, and ensuring the appearance of the silicon wafer to be complete without obvious chromatic aberration, dirt, spots or cracks. In this example, both the performance parameters and the microphotographs were acceptable.
TABLE 5
| Reduced weight/g | Center point reflectivity/% | |
| Standard requirements | 1.4±0.05 | ＜9 |
| Example IV | 1.39 | 7.8 |
TABLE 6
| Open circuit voltage/v | Short-circuit current/a | Fill factor | Conversion efficiency/% | |
| Prior Art | 0.6827 | 10.0038 | 78.77 | 22.02 |
| Example IV | 0.6833 | 10.0029 | 78.81 | 22.05 |
The embodiment has the advantages and positive effects that:
the texturing process designed by the embodiment is particularly suitable for texturing square silicon wafers with the size of 160-260mm, an oxide layer which is easy to remove is formed by oxidizing metal impurities on the surface of the silicon wafers in advance, and then the oxide layer is complexed after the first acid washing to form a water-soluble complex, so that greasy dirt attached to the oxide layer can be effectively removed, the surface cleanliness of the silicon wafers is improved, a good surface foundation is provided for the subsequent preparation of the textured surface, the microstructure of the battery surface of the silicon wafers is more uniform, the silicon dioxide layer depth of the silicon wafers after the first acid washing, namely the single-sided thinning depth is 1-2um, and the silicon dioxide layer depth of the silicon wafers after the first acid washing is completely controllable.
The pretreatment comprises rough polishing treatment and pre-cleaning treatment, wherein the purpose of the rough polishing treatment is to remove a cutting damage layer on the surface of the silicon wafer, and a flat surface is formed after thinning, so that the subsequent preparation of a suede is facilitated; the pre-cleaning is to remove the residual metal ions and organic matters on the surface of the silicon wafer. The texturing is to form pyramid-shaped textured surfaces which are uniform in size and are distributed on the whole silicon surface on the surface of the silicon wafer. Sequentially carrying out post-treatment, second acid washing and drying on the silicon wafer after the texturing, wherein the post-treatment is to remove additives and organic matters remained on the surface of the silicon wafer; the second acid washing is to remove silicon dioxide and metal ions marked on the silicon wafer to form a suede with better hydrophobicity; the drying comprises a hot water full lifting groove and a drying groove, and the hot water cleans the residual liquid of the silicon wafer, so that the water trace on the surface of the silicon wafer is reduced, and the subsequent drying is facilitated; the drying groove is used for drying the water mark on the surface of the silicon wafer by hot air; and the dried silicon wafer is discharged from the discharging groove, and finally the silicon wafer with the total weight of 0.45-1.45g and uniform microstructure of the single-piece thinning is obtained, so that the conductivity of the battery is improved by 0.01-0.03%.
The washing tanks are arranged after the oxidation, the first acid washing, the pretreatment, the texturing, the post-treatment and the second acid washing, so that the purpose of removing the liquid medicine on the surface layer of the silicon wafer is achieved, and meanwhile, the organic solvent and the metal ions remained on the surface of the silicon wafer can be removed, the removal of the residues of the metal impurities on the surface of the silicon wafer is facilitated, the surface cleanliness of the silicon wafer is improved, and the electrical property of a battery is improved.
The present application is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present application are intended to be included in the scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims (10)
1. The large-size battery texturing equipment is characterized by sequentially comprising an oxidation unit, a first acid washing unit, a pretreatment unit, a texturing unit, a post-treatment unit, a second acid washing unit and a drying unit;
the oxidation unit is used for oxidizing the silicon wafer by adopting ozone to obtain a silicon dioxide oxide layer;
the first acid washing unit is used for washing a silicon dioxide oxide layer on the silicon wafer by adopting hydrofluoric acid liquid medicine;
the pretreatment unit is used for performing rough polishing and pre-cleaning on the silicon wafer by adopting sodium hydroxide liquid medicine;
the texturing unit is used for texturing the silicon wafer by adopting mixed liquor of sodium hydroxide, an additive and water;
the post-treatment unit is used for cleaning the silicon wafer after texturing by adopting a mixed solution of hydrogen peroxide and sodium hydroxide;
the second pickling unit is used for pickling the silicon wafer subjected to texturing by adopting a mixed solution of hydrofluoric acid and hydrochloric acid;
and the drying unit is used for drying the pickled silicon wafer to finish the preparation.
2. The large-sized battery texturing apparatus according to claim 1, wherein,
the oxidation unit comprises a feeding groove and an oxidation groove;
the feeding groove is used for bubbling cleaning the silicon wafer by pure water;
the oxidation tank is used for removing metal impurities on the silicon wafer by adopting sodium hydroxide liquor with the solution ratio of 3-4%, and introducing ozone to oxidize the silicon wafer at the temperature of 40-80 ℃ for 1-5min to obtain the silicon dioxide oxide layer.
3. The large-sized battery texturing apparatus according to claim 1, wherein,
the first acid washing unit comprises a first acid washing tank, and the first acid washing tank is used for washing a silicon dioxide oxide layer on a silicon wafer for 1-5min by adopting hydrofluoric acid liquid medicine with the solution ratio of 10-15%.
4. The large-sized battery texturing apparatus according to claim 1, wherein,
the pretreatment unit comprises a rough polishing groove and a pre-cleaning groove;
the rough polishing groove is used for rough polishing the silicon wafer at the temperature of 60-100 ℃ by adopting sodium hydroxide liquid medicine with the solution ratio of 4-4.5%, and removing a cutting damage layer;
the pre-cleaning tank is used for cleaning the silicon wafer for 1-5min at the temperature of 40-80 ℃ by adopting a mixed solution of hydrogen peroxide with the solution ratio of 4-7% and sodium hydroxide with the solution ratio of 0.2-0.5%.
5. The large-sized battery texturing apparatus according to claim 1, wherein,
the texturing unit comprises a texturing groove, wherein the texturing groove is used for texturing a silicon wafer at the temperature of 60-100 ℃ for 3.5-9.5min by adopting mixed liquid medicine of sodium hydroxide, an additive and water to obtain textured surfaces; wherein the solution ratio of the sodium hydroxide is 4-4.5%, and the solution ratio of the additive is 0.6-1%.
6. The large-sized battery texturing apparatus according to claim 1, wherein,
the post-treatment unit comprises a post-cleaning tank, wherein the post-cleaning tank is used for cleaning the silicon wafer for 1-5min at the temperature of 40-80 ℃ by adopting a mixed solution of hydrogen peroxide with the solution ratio of 4-7% and sodium hydroxide with the solution ratio of 0.2-0.5%.
7. The large-sized battery texturing apparatus according to claim 1, wherein,
the second pickling unit comprises a second pickling tank, and the second pickling tank is used for pickling the silicon wafer at normal temperature by adopting mixed solution of hydrofluoric acid with the solution ratio of 10-15% and hydrochloric acid with the solution ratio of 10-15%.
8. The large-sized battery texturing apparatus according to claim 1, wherein,
the last step of the oxidation unit, the first pickling unit, the pretreatment unit, the texturing unit, the post-treatment unit and the second pickling unit is respectively provided with a first washing tank, a second washing tank, a third washing tank, a fourth washing tank, a fifth washing tank and a sixth washing tank, which are all used for cleaning the silicon wafer by pure water for 0.5-3.5min.
9. The large-sized battery texturing apparatus according to claim 1, wherein,
the drying unit comprises a full lifting groove, a drying groove and a discharging groove;
the full lifting groove is used for cleaning the silicon wafer for 0.5-3.5min by adopting hot water at 50-90 ℃;
the drying tank is used for drying the silicon wafer for 4-8min at the temperature of 60-100 ℃;
the blanking groove is used for receiving the silicon wafer after texturing.
10. A large-size battery texturing method, which is characterized by comprising the following steps:
placing the silicon wafer in sodium hydroxide liquor with the solution ratio of 3-4%, and introducing ozone to oxidize the silicon wafer at the temperature of 40-80 ℃ for 1-5min to obtain a silicon dioxide oxide layer;
cleaning a silicon dioxide oxide layer on a silicon wafer for 1-5min by adopting hydrofluoric acid liquid medicine with the solution ratio of 10-15%;
coarse polishing the silicon wafer at 60-100deg.C by adopting sodium hydroxide solution with solution ratio of 4-4.5%;
after cleaning the roughly polished silicon wafer, adopting mixed liquor of sodium hydroxide, additives and water to texture the silicon wafer for 3.5-9.5min at the temperature of 60-100 ℃;
cleaning the silicon wafer after texturing, and then pickling the silicon wafer at normal temperature by adopting a mixed solution of hydrofluoric acid with the solution ratio of 10-15% and hydrochloric acid with the solution ratio of 10-15%;
and drying the pickled silicon wafer to finish the preparation.
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