Nickel (Ni) and its alloys are important multifunctional materials for the fabrication of integrated circuits, as either the absorber for the extreme ultraviolet lithography masks and/or interconnect metals at the nanometer scale. However, these applications require that Ni to be patterned controllably, selectively, and anisotropically—requirements that can only be met with a plasma based atomic layer etch (ALE) process. In this work, a plasma-thermal ALE approach is developed to pattern Ni, utilizing a nitrogen plasma to form NixN at the surface, formic acid (FA) vapor to selectively remove the NixN layer, and a low-energy Ar+ sputter process to remove carbon residue left by the FA prior to the subsequent nitridation step. This three step ALE process was shown effective to etch Ni with a rate of 1.3 ± 0.17 nm/cycle while maintaining surface smoothness.

中文翻译：

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Ni原子层蚀刻的等离子体氮化

镍 (Ni) 及其合金是制造集成电路的重要多功能材料，可作为极紫外光刻掩模的吸收剂和/或纳米级互连金属。然而，这些应用要求对 Ni​​ 进行可控、选择性和各向异性图案化，而这些要求只能通过基于等离子体的原子层蚀刻 (ALE) 工艺来满足。在这项工作中，开发了一种等离子体热 ALE 方法来对 Ni 进行图案化，利用氮等离子体在表面形成 NixN，利用甲酸 (FA) 蒸汽选择性地去除 NixN 层，并利用低能 Ar+ 溅射工艺去除 NixN 层。在后续氮化步骤之前 FA 留下的碳残留物。事实证明，这种三步 ALE 工艺能够以 1.3 ± 0.17 nm/cycle 的速率有效蚀刻 Ni，同时保持表面光滑度。