Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
ACS Nano. 2012 Sep 25;6(9):8342-8. doi: 10.1021/nn303085k. Epub 2012 Aug 30.
Microphase separation of a polyisoprene-b-polystyrene-b-polyferrocenylsilane (PI-b-PS-b-PFS) triblock terpolymer film during chloroform solvent-annealing formed a 44 nm period square-symmetry array of alternating PI and PFS cylinders in a PS matrix. This nanostructure was converted to either a positive pattern of posts or a negative pattern of holes with tunable diameter by oxygen reactive ion etching or by surface reconstruction in a solvent, respectively, and coexisting post and hole patterns were also formed. Square arrays of silicon posts, pits, and inverted pyramids were fabricated by pattern transfer from the triblock terpolymer film into silicon substrates. The morphology of the triblock terpolymer film varied with the chloroform vapor pressure during solvent annealing, which was explained by selective swelling of the PI block at high vapor pressures. This triblock terpolymer system provides a convenient block copolymer lithography process for generation of nanoscale posts or holes with square symmetry.
聚异戊二烯-嵌段-聚苯乙烯-嵌段-聚二茂铁硅烷（PI-b-PS-b-PFS）三嵌段共聚物膜在氯仿溶剂退火过程中的微相分离形成了 44nm 周期的正方形对称排列的交替 PI 和 PFS 圆柱在 PS 基体中。这种纳米结构分别通过氧反应离子刻蚀或在溶剂中的表面重构，转化为具有可调直径的正柱图案或负孔图案，并且还形成了共存的柱和孔图案。通过从三嵌段共聚物膜到硅衬底的图案转移，制造了硅柱、凹坑和倒金字塔的正方形阵列。三嵌段共聚物膜的形态随溶剂退火过程中氯仿蒸汽压力而变化，这可以通过在高蒸汽压力下对 PI 嵌段的选择性溶胀来解释。这种三嵌段共聚物体系为具有正方形对称性的纳米级柱或孔的生成提供了一种方便的嵌段共聚物光刻工艺。
