Research On Silicon Wafer Surface Contamination Cleaning And Texturing Technolog

Solar energy reserves are huge,not subject to geographical restrictions and green and clean features make it play a decisive role in solving the human energy crisis and improving environmental pollution,photovoltaic power generation is constantly becoming an important part of the current and future booming renewable energy sector,the rapid development of photovoltaic technology is expected to accelerate the achievement of global dual carbon goals.Currently,the research and development in the field of high-efficiency and low-cost silicon-based solar cells has been a hot spot in the photovoltaic industry.Reducing the optical loss(high-efficiency fleece making)and electrical loss(new structural design)of silicon-based cells is the key to achieving highefficiency photoelectric conversion efficiency of solar cells.This paper systematically studies the morphology and introduction mechanism of wafer surface staining,and proposes a cleaning process for wafer surface staining based on the results of the study.he effect of surface staining on the behavior of metal-assisted chemical etching was also systematically investigated,while a novel velvet production process was developed and realized the preparation of ultra-low reflectivity inverted pyramidal velvet surface on silicon wafer.First,this thesis systematically investigates the composition and sources of three types of staining on the silicon wafer surface,and conducts copper etching and copper deposition experiments on the stained wafers to study the effects of staining on the etching and deposition of silicon wafers.The results of the study show that: White spot staining mainly contains Si,Ca,C,O four elements,and the same composition of the consumable sticky bar adhesive used in cutting;white spot staining is mainly composed of Si elements,the morphology and cutting silicon waste with the same lamellar structure;caliper print staining mainly contains Na,Si,O,C,F five elements,its chemical composition is similar to the cutting fluid.In the experiments of etching and deposition,it was found that sticky bar adhesive staining would obstruct the contact between silicon wafer and etching solution,resulting in uneven etching and uneven copper deposition due to the existence of the concentration polarization effect.After etching and deposition of caliper-print stained silicon wafers,there is still staining residue on the wafer surface.After the white spot stained wafer was etched,the wafer below the stain was not etched,and the deposition of copper particles at the stain was much larger than other areas.Finally,the white spot stain,white spot stain,and caliper mark stain were completely removed from the wafer surface after 5 min,80 s,and 40 s of cooperative ultrasonic treatment with KOH solution,respectively.Secondly,this thesis investigated the effects of anionic and cationic surfactants and anionic and cationic surfactants on metal-assisted chemical etching of single-crystal silicon wafers.By comparing the etching rate,reflectivity and surface microscopic morphology of silicon wafers,it was found that the compound surfactants were more significant than single surfactants in enhancing the etching rate of silicon wafers.The compounding ratio was also optimized,and it was found that the best etching effect was achieved when the compounding ratio of anionic surfactant SDS and cationic surfactant CTAB was 1:2,and the inverted pyramidal suede structure formed was more uniform and dense,and the structure was complete.Finally,this thesis also explored the effects of etching temperature,etching time,and concentration of compound surfactant on etching,and on the sub-basis,the optimal process conditions were explored,and it was found through experiments that when the etching temperature was 35°C,etching time was 6 min,and concentration of compound surfactant was 0.014 m M,the optimal performance of the trapped light structure prepared on the silicon wafer surface,with reflectivity as low as 5.5%,and an etching rate increase of about 13 times compared to that without the addition of surfactant,provides a new idea for the future industrial preparation of inverted pyramidal chamois structures.