Doise Jan, Bezik Cody, Hori Masafumi, de Pablo Juan J, Gronheid Roel
Department of Electrical Engineering (ESAT) , KU Leuven , Kasteelpark Arenberg 10 , B-3001 Heverlee , Belgium.
imec , Kapeldreef 75 , B-3001 Heverlee , Belgium.
ACS Nano. 2019 Apr 23;13(4):4073-4082. doi: 10.1021/acsnano.8b08382. Epub 2019 Mar 21.
Templated assembly of cylindrical block copolymers provides a promising strategy for patterning holes at the nanoscale. However, remaining challenges include the ability to achieve defect-free patterns and to generate architectures useful for device patterning. The aim of this work is to gain insight into the influence of homopolymer addition on the assembly of a cylindrical block copolymer in confined space. To do so, a concerted examination that relies on experiments and simulations is carried out for different block copolymer/homopolymer blends. It is shown that by adding a majority block homopolymer with low molecular weight (compared to the blocks that make up the block copolymer), the pattern quality is significantly improved and a larger defect-free window is obtained in terms of template dimensions for two-hole features in elliptical confinements. The redistribution of the homopolymer chains effectively enables the assembly of two cylinders, despite the geometrical mismatch between the elliptical shape of the confinement and the natural hexagonal ordering of the unguided block copolymer. Monte Carlo simulations show that the homopolymer segregates to the spaces in the template that are entropically unfavorable for the block copolymer. This work serves to highlight the importance of optimizing block copolymer formulation.
圆柱形嵌段共聚物的模板组装为纳米级孔的图案化提供了一种很有前景的策略。然而，仍然存在的挑战包括实现无缺陷图案以及生成对器件图案化有用的结构。这项工作的目的是深入了解均聚物添加对受限空间中圆柱形嵌段共聚物组装的影响。为此，针对不同的嵌段共聚物/均聚物共混物进行了一项依赖于实验和模拟的协同研究。结果表明，通过添加低分子量的多数嵌段均聚物（与构成嵌段共聚物的嵌段相比），图案质量得到显著改善，并且在椭圆形受限环境中两孔特征的模板尺寸方面获得了更大的无缺陷窗口。尽管受限环境的椭圆形形状与未引导的嵌段共聚物的自然六边形排列之间存在几何不匹配，但均聚物链的重新分布有效地促成了两个圆柱体的组装。蒙特卡罗模拟表明，均聚物会偏析到模板中对嵌段共聚物熵不利的空间。这项工作有助于突出优化嵌段共聚物配方的重要性。
