多晶矽晶片氣相製絨反應器設計與絨面調整之研究

Abstract

本論文提出新的酸蝕刻製程-氣相製絨(vapor etching, VE)，為取代現今如反應離子蝕刻法(reactive ion etching, RIE)、金屬催化蝕刻(metal catalytic chemical etching, MCCE)、噴砂等製絨方式，以改善高成本，操作複雜且有後續汙染物處理等問題，並有效提高電池效率。 氣相製絨透過不同的反應器設計，調整酸成份、溫度、壓力、氣流等因子，得知各變因對於氣相蝕刻均勻度及表面結構的關係。目前己確認最佳酸蒸氣(A酸)重量百分比例為 HNO3：HF：H2O = 37.3：16：46.7，B 酸流量控制在 1.52ml/min，最高腔溫 140C，空氣流量 30slpm，常壓，晶片間距 1cm 下，可製作出切割線痕較不明顯，均勻性佳之 DW 製絨晶片，且再現性佳(重複驗證五次以上)。 利用混酸滴定方法，除了能夠分析最佳酸液成份，亦能將使用過的酸調回 成最佳酸重覆使用，以達到零廢酸之目的。DW 多晶片經 VE 製絨及絨面調整處理後之反射率為 19%，以鈍化發射極觸點(passivated emitter and rear cell, PERC)處理後的電池效率可達 19.5%，達傳統酸製絨的電池效率。

This paper proposes a new acid etching process, vapor etching (VE), to replace the current reactive ion etching (RIE), metal catalytic chemical etching (MCCE), sand blasting, etc. The method is to improve the high cost, complicated operation and subsequent pollutant treatment, and effectively improve the solar cell efficiency. Vapor etching is designed through different reactors to adjust the acid composition, temperature, pressure, gas flow and other factors to understand the relationship between the various factors and the surface etching uniformity and surface structure. At present, the weight percentage of the best acid vapor (A acid) has been confirmed as HNO3: HF: H2O = 37.3: 16:46.7, and the B acid is controlled 15-2ml/min, and the maximum reactor temperature is 140˚C. The operation of air flow rate is 30slpm, using atmospheric pressure, and the wafer spacing is 1cm. It is possible to produce DW textured wafers with less obvious line marks and good uniformity, and good reproducibility (It can be repeated for more than five times). The optimum acid composition is analyzed by the mixed acid titration method, and the used acid can be adjusted back to the optimum acid for repeated use to achieve zero waste acid. The reflectivity of the DW multi-wafer after VE texturing and texturing surface adjusted is 19%, and the efficiency of the battery after the passivated emitter and rear cell (PERC) treatment is 19.5%, and can reach the solar cell efficiency, which textured by acid etching.