Ionic Liquids as Additives to Polystyrene-Block-Poly(Methyl Methacrylate) Enabling Directed Self-Assembly of Patterns with Sub10 nm Features
Ionic Liquids as Additives to Polystyrene-Block-Poly(Methyl Methacrylate) Enabling Directed Self-Assembly of Patterns with Sub10 nm Features
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离子液体作为聚苯乙烯嵌段聚甲基丙烯酸甲酯的添加剂，实现具有亚 10 nm 特征的图案的定向自组装
DOI：
10.1021/acsami.8b02990
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发表时间：
2018
影响因子：
9.5
通讯作者：
Paul F. Nealey
中科院分区：
文献类型：
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作者：
Xuanxuan Chen;Chun Zhou;Shuangjun Chen;Gordon S. W. Craig;Takahiro Dazai;Ken Miyagi;Takaya Maehashi;Akiyoshi Yamazaki;Roel Gronheid;Mark P. Stoykovich;Paul F. Nealey
聚苯乙烯-嵌段聚（甲基丙烯酸甲酯）（PS-b-PMMA）是定向自组装（DSA）研究和开发中的典型嵌段共聚物之一，在工业相关的300毫米晶圆上加工具有标准化协议。然而，使用PS-b-PMMA将DSA模式缩放到20 nm以下的间距受到相对较低的Flory - Huggins相互作用参数χ的阻碍。在这里，我们研究了在PS-b-PMMA中加入少量离子液体（ILs）的方法，该方法选择性地分离到PMMA结构域，并有效地提高了χ参数，从而提高了模式分辨率。IL添加剂的量足够小，导致PS-b-PMMA表面和界面性能的变化有限，从而通过自由表面的热退火保持工业友好的加工。比较研究了三种不同il的组成过程窗口、增加χ的能力和热稳定性。通过在低分子量PS-b-PMMA （Mn = 10.3k-b-9.5k）中加入约3.1 vol %的IL，我们在特征尺寸<8.5 nm的层状结构的化学图纹基底上证明了DSA。PS-b-PMMA /IL共混物与先前开发的标准化工艺的兼容性表明，这种共混材料可以提供一种具有PS-b-PMMA加工优势的10纳米以下光刻解决方案。
Polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) is one of the prototypical block copolymers in directed self-assembly (DSA) research and development, with standardized protocols in place for processing on industrially relevant 300 mm wafers. Scaling of DSA patterns to pitches below 20 nm using PS-b-PMMA, however, is hindered by the relatively low Flory−Huggins interaction parameter, χ. Here, we investigate the approach of adding small amounts of ionic liquids (ILs) into PS-b-PMMA, which selectively segregates into the PMMA domain and effectively increases the χ parameter and thus the pattern resolution. The amount of IL additive is small enough to result in limited changes in PS-b-PMMA’s surface and interfacial properties, thus maintaining industry-friendly processing by thermal annealing with a free surface. Three different ILs are studied comparatively regarding their compositional process window, capability of increasing χ, and thermal stability. By adding ∼3.1 vol % of the champion IL into a low-molecular-weight PS-b-PMMA (Mn = 10.3k-b-9.5k), we demonstrated DSA on chemically patterned substrates of lamellar structures with feature sizes <8.5 nm. Compatibility of the PS-b-PMMMA/IL blends with the standardized processes that have been previously developed suggests that such blend materials could provide a drop-in solution for sub-10 nm lithography with the processing advantages of PS-b-PMMA.