多晶矽之蝕刻在實務上多使用HNO3、HF及CH3COOH三種成份之混合溶液,其製程原理包含二道反應步驟:
Si + 4 HNO₃ → SiO₂ + 4 NO₂ + 2 H₂O SiO₂ + 6HF → H₂SiF₆ + 2H₂O
先利用HNO3之強酸性將多晶矽氧化成為 SiO₂,再由HF將 SiO₂去除而CH3COOH則扮演類似緩衝溶液中H+提供者來源,使蝕刻率能保持穩定,此種通稱為”Poly-Etch”之混合溶液也常用於控片回收使用。
Poly silicone etch normal used mixture of nitric acid(HNO3) and hydrofluoric acid(HF) in water or acetic acid(CH3COOH) ,
1.HNO3 oxidizes the silicone to form an SiO2 layer,
2.HF used to dissolve and removes the oxide layer (SiO2) at the same time,
3.DI and acetic acid can be used to dilute the etchant, and reduce the etching rate, but the acetic acid is preferred
Si + 2HNO₃ + 6HF → H₂SiF₆ + 2NO₂ + 2H₂O
包裝形式:200L桶裝