PF5/C4F8 혼합 가스 기반 저온 SiO2 식각 공정의 플라즈마 화학 및 식각 거동 분석 = Plasma Chemistry and Etching Behavior of Low-Temperature SiO2 Etching Using PF5/C4F8 Mixed Gases

다국어 초록 (Multilingual Abstract)

This study investigates the effect of PF5–C4F8 mixed-gas composition on the SiO2 etching characteristics in an inductively coupled plasma (ICP) etching system operated at a low temperature of –30 ℃. The behavior of reactive species in the plasma was analyzed using optical emission spectroscopy (OES), while neutral and ionic species that are difficult to detect with OES were identified using quadrupole mass spectrometry (QMS). The analysis revealed that PF5 generated high-mass PFx ions together with fluorine radicals, inducing physical bombardment on the substrate surface. Meanwhile, C₄F₈ exhibited a high dissociation rate, producing F and CFx radicals that enhanced chemical etching reactions. In addition, increasing the bias power elevated the physical contribution of PFx ions, resulting in a higher overall etch rate. These observations quantitatively demonstrate the etching behavior and plasma chemistry occurring under PF5–C4F8-based low-temperature plasma conditions.