The behavior of Si 3 N 4 etching with ion-incidence angle in high-density CF 4 , CHF 3 , and C 2 F 6 plasmas was investigated to understand the effect of discharge chemistry on the etch characteristics of Si 3 N 4 . The normalized etch yield (NEY) plots suggest that for all plasmas considered herein, physical sputtering is more prevalent than ion-assisted chemical etching as the Si 3 N 4 etching mechanism. In the cases of the CF 4 and C 2 F 6 plasmas, the NEYs at an ion-incidence angle of 60° were greater than unity because the thickness and the fluorine-to-carbon (F/C) ratio of the steady-state fluorocarbon films (st-st FC films) on the Si 3 N 4 surfaces decreased and increased, respectively, as the ion-incidence angle was increased from 0° to 60°. In contrast, the NEY at this angle in the CHF 3 plasma was close to unity, as a result of a small change (or a very marginal decrease) in the thickness and the F/C ratio of the st-st FC film. Additionally, the NEY at an ion-incidence angle of 60° was higher in C 2 F 6 plasma compared to CF 4 plasma because the changes in the thickness and the F/C ratio of the st-st FC film were greater in the C 2 F 6 plasma than those in the CF 4 plasma.

中文翻译：

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高密度 CF4、CHF3 和 C2F6 等离子体中不同离子入射角的 Si3N4 蚀刻速率

研究了在高密度 CF 4 、CHF 3 和 C 2 F 6 等离子体中具有离子入射角的 Si 3 N 4 蚀刻行为，以了解放电化学对 Si 3 N 4 蚀刻特性的影响。归一化蚀刻产率 (NEY) 图表明，对于此处考虑的所有等离子体，物理溅射比作为 Si 3 N 4 蚀刻机制的离子辅助化学蚀刻更为普遍。在 CF 4 和 C 2 F 6 等离子体的情况下，离子入射角为 60° 的 NEY 大于 1，因为稳态的厚度和氟碳 (F/C) 比随着离子入射角从0°增加到60°，Si 3 N 4 表面上的碳氟化合物膜（st-st FC膜）分别减少和增加。相比之下，CHF 3 等离子体中这个角度的NEY接近统一，由于 st-st FC 薄膜的厚度和 F/C 比的微小变化（或非常微小的下降）。此外，与 CF 4 等离子体相比，C 2 F 6 等离子体中离子入射角为 60°时的 NEY 更高，因为 C 中 st-st FC 膜的厚度和 F/C 比的变化更大。 2 F 6 等离子体比CF 4 等离子体中的那些。