Highly selective and vertical profile etching of thermally grown SiO₂ films using thin metallic Ru mask films was investigated in a commercial inductively coupled plasma etcher. The effects of varying chamber pressure, substrate bias, and gas composition on etch performance were all investigated. Selectivities (measured as the SiO₂ etch rate divided by the Ru etch rate) ranging from 50 to as high as 370 were measured under various process conditions without compromising the etch profile quality. It was found that fluorocarbon gas mixtures (CF₄/CHF₃ and CF₄/C₄F₈) gave the best results. The addition of SF₆ to the gas mixture dramatically reduced selectivity, resulting in significant Ru mask faceting and necking in the etched pillars and is not recommended for use in a standard Ru/SiO₂ etch process.

中文翻译：

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使用钌膜作为蚀刻掩模对二氧化硅进行高选择性和垂直蚀刻

在商用电感耦合等离子体蚀刻机中研究了使用薄金属 Ru 掩模膜对热生长的 SiO ₂膜进行高选择性和垂直剖面蚀刻。研究了不同腔室压力、衬底偏压和气体成分对蚀刻性能的影响。在不影响蚀刻轮廓质量的情况下，在各种工艺条件下测量了范围从 50 到高达 370 的选择性（测量为 SiO ₂蚀刻速率除以 Ru 蚀刻速率）。发现碳氟化合物气体混合物（CF ₄ /CHF ₃和CF ₄ /C ₄ F ₈）给出了最好的结果。添加SF ₆对气体混合物的选择性显着降低，导致蚀刻柱中显着的 Ru 掩模刻面和颈缩，不推荐用于标准 Ru/SiO ₂蚀刻工艺。