Patterning of thin films with lithography techniques for making semiconductor devices has been facing increasing difficulties with feature sizes shrinking to the sub-10 nm range, and alternatives have been actively sought from area-selective thin film deposition processes. Here, an entirely new method is introduced to self-aligned thin-film patterning: area-selective gas-phase etching of polymers. The etching reactions are selective to the materials underneath the polymers. Either O₂ or H₂ can be used as an etchant gas. After diffusing through the polymer film to the catalytic surfaces, the etchant gas molecules are dissociated into their respective atoms, which then readily react with the polymer, etching it away. On noncatalytic surfaces, the polymer film remains. For example, polyimide and poly(methyl methacrylate) (PMMA) were selectively oxidatively removed at 300 °C from Pt and Ru, while on SiO₂ they stayed. CeO₂ also showed a clear catalytic effect for the oxidative removal of PMMA. In H₂, the most active surfaces catalysing the hydrogenolysis of PMMA were Cu and Ti. The area-selective etching of polyimide from Pt was followed by area-selective atomic layer deposition of iridium using the patterned polymer as a growth-inhibiting layer on SiO₂, eventually resulting in dual side-by-side self-aligned formation of metal-on-metal and insulator (polymer)-on-insulator. This demonstrates that when innovatively combined with area-selective thin film deposition and, for example, lift-off patterning processes, self-aligned etching processes will open entirely new possibilities for the fabrication of the most advanced and challenging semiconductor devices.

中文翻译：

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通过区域选择性蚀刻聚合物的自对准薄膜图案

随着特征尺寸缩小到亚 10 nm 范围，使用光刻技术对薄膜进行图案化以制造半导体器件面临越来越大的困难，并且已经积极寻求区域选择性薄膜沉积工艺的替代方案。在这里，引入了一种全新的自对准薄膜图案化方法：聚合物的区域选择性气相蚀刻。蚀刻反应对聚合物下方的材料具有选择性。O ₂或 H ₂可用作蚀刻气体。在通过聚合物膜扩散到催化表面后，蚀刻剂气体分子分解成各自的原子，然后很容易与聚合物反应，将其蚀刻掉。在非催化表面上，聚合物膜保留。例如，聚酰亚胺和聚（甲基丙烯酸甲酯）（PMMA）在 300 °C 下从 Pt 和 Ru 中选择性氧化去除，而它们留在 SiO _{2 上}。CeO ₂对PMMA的氧化去除也表现出明显的催化作用。在 H ₂，催化 PMMA 氢解最活跃的表面是 Cu 和 Ti。从 Pt 对聚酰亚胺进行区域选择性蚀刻，然后使用图案化聚合物作为 SiO ₂上的生长抑制层进行铱的区域选择性原子层沉积，最终导致双并排自对准形成金属-金属上和绝缘体（聚合物）绝缘体上。这表明，当创新地与区域选择性薄膜沉积以及剥离图案化工艺相结合时，自对准蚀刻工艺将为制造最先进和最具挑战性的半导体器件开辟全新的可能性。