| 摘要: | 太陽能電池製程中影響產量的主因在於晶圓切割階段，而現今切割方式以線鋸加工為主流，其優點為可複線式加工，加工效率高。但此方式為接觸式加工，過程中易產生加工應力進而造成晶圓破裂損壞，及磨粒無法完全使用，且磨粒回收過程複雜並造成環境污染。因此，近年來相關文獻中提出以線切割放電加工方式切割矽晶圓，使用此法可有效改善線鋸加工之缺點，但因目前仍以加工單晶矽材料為主，而多晶矽材料加工方面的文獻甚少，主要原因為相較於單晶矽材料，多晶矽因具有晶界多變、電阻大等特性導致無法順利加工，故本研究嘗試採用線切割放電加工加工多晶矽晶圓，並對其加工特性做一探討。 本研究主要分成二大部份，第一部份為前置實驗，以焦磷酸鈉溶液作為加工液，固定莫爾濃度為0.05M，添加不同比例磷酸，對加工可行性進行探討，過程中以不同製程參數進行實驗，並了解加工特性之影響趨勢。第二部份則利用田口實驗規劃法，，針對加工表面磷含量對各不同的加工參數作ㄧ探討。經由實驗結果得知，最佳製程組合參數為，焦磷酸鈉莫爾濃度0.025M、磷酸添加比1000：15、加工電流1.2A、脈衝時間6μs以及休止時間9μs。經由EDS檢測後，可以得到最佳表面磷含量0.67wt％。並藉由Mapping以及Line scanning分析可證實磷酸添加進焦磷酸鈉加工液中可改善加工表面磷含量並抑制雜質的滲入，同時亦可獲得表面摻雜之效果。 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. |
