Abstract Directed Self-Assembly of block copolymers is a lithographic technique being developed to reach sub-10 nm technological nodes. Recently, high chi block copolymers have been developed to achieve higher resolution. In this paper, the high chi system investigated is a modified polystyrene-b-poly(methyl methacrylate)(PS-b-PMMA) presenting a pitch of 18 nm. One critical step for its integration is the PMMA removal selectively to the PS. Two approaches to remove the PMMA phase are presented, highlighting the challenges encountered due to its smaller dimensions. The first one is a full dry approach based on a CH4/N2 chemistry, which presents some bridge formation due to intensive sidewalls passivation and to a species confinement effect accentuated by the small 9-nm critical dimension of the lines. Therefore, the main high chi PS-b-PMMA dry etching difficulties come from the trade-off between obtaining high selectivity and avoiding bridge formation. The second approach is a mixed wet and dry PMMA removal process based on UV exposure followed by solvent rinse. An Ar/O2 dry brush layer opening was developed and the pattern transfer into the SiO2 and Si underlayers is demonstrated for the high chi PS-b-PMMA.

中文翻译：

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用于定向自组装 (DSA) 应用的亚 10 nm 半节距高 chi 嵌段共聚物的蚀刻

摘要 嵌段共聚物的定向自组装是一种正在开发的光刻技术，以达到亚 10 nm 的技术节点。最近，已开发出高 chi 嵌段共聚物以实现更高的分辨率。在本文中，研究的高 chi 系统是一种间距为 18 nm 的改性聚苯乙烯-b-聚（甲基丙烯酸甲酯）（PS-b-PMMA）。其集成的一个关键步骤是选择性地将 PMMA 去除到 PS。提出了两种去除 PMMA 相的方法，强调了由于其较小的尺寸而遇到的挑战。第一个是基于 CH4/N2 化学的全干法，由于密集的侧壁钝化和 9nm 线的小临界尺寸加剧了物种限制效应，它呈现出一些桥的形成。所以，主要的高 chi PS-b-PMMA 干蚀刻困难来自获得高选择性和避免桥形成之间的权衡。第二种方法是基于紫外线照射和溶剂冲洗的混合干湿 PMMA 去除工艺。开发了 Ar/O2 干刷层开口，并证明了高 chi PS-b-PMMA 的图案转移到 SiO2 和 Si 底层。