| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 98 === During solar cell processing, wafer cutting is an import procedure for yield, nowadays wire saw is the main cutting process, it has multi-wire with high efficiency, but has produced stress while cutting, it may let wafer break, and the particle can not be used fully, the particle will contaminate environment. Therefore, wire electrical discharge machining was investigated to improve wire saw processing, but most of research of material is single-crystal silicon, the poly-crystal investigate is few, because poly-crystal silicon with higher resistance, it is hard to machine for wire electrical discharge machining.
This study is divided into two major parts, the first part of the pre-test to sodium pyrophosphate solution as dielectric, the Mole concentration 0.05M, adding different amounts of phosphoric acid to explore the feasibility of processing, the experiment with the different parameters and to understand the effect of processing characteristics of the trend. The second part o use the Taguchi method for processing the surface of phosphorus content on the processing with different parameters. The experimental results indicate that the best combination of process parameters, the Mole concentration of sodium pyrophosphate 0.025M, phosphoric acid than 1000:15, processing current 1.2A, pulse time 6μs and resting time 9μs. Detected by EDS, you can get the best surface phosphorus content 0.67wt%. By Mapping and Line scanning analysis confirm the processing of phosphoric acid added to sodium pyrophosphate solution can improve the processing of phosphorus content in the surface and inhibits the infiltration of impurities, while the effect of doping the surface can be obtained.
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