In situ infiltration of templated block-copolymer nanopatterns via Atomic Layer Deposition

Direct self-assembling (DSA) of Block-Copolymers (BCPs) (DSA-BCPs) is considered a unique approach to overcome the spatial resolution limit of present top-down methods with the benefit of low processing cost and energy consumption. This bottom-up methodology is based on the opposite nature of two covalently linked polymers that self-assemble to form patterns with critical dimensions of molecular size. To improve the final properties of the nanostructured pattern and expand the possibilities of this new technology, Sequential Infiltration Synthesis (SIS) using Atomic Layer Deposition (ALD) (SIS-ALD) has been recently developed: when SIS-ALD is applied on these soft-materials, the gas precursors can be sequentially infiltrated in the organic matrix, modifying its properties and/or allowing the inorganic material deposition using the polymer as template. Understanding the relation between SIS-ALD parameters and the resulting properties and performance of infiltrated materials is critical to obtain a material with optimal structural, mechanical and electrical properties to reach practical functional devices. However, the complete comprehension of the process mechanism and the exhaustive characterization of the materials’ properties have not yet followed through the expanding fabrication capabilities. Therefore, in situ GISAXS during SIS-ALD of nanostructured DSA-BCPs at NCD-SWEET beamline will provide information about the SIS-ALD process (kinetics) of TiO2 but also about the morphological changes of the supported polymers and conformal deposition of the inorganic material depending on the conditions applied. For that, we will use a recently built ALD reactor at ALBA, which was designed to be coupled to different beamlines (as NCD-SWEET and NOTOS), and that will allow us the possibility of measuring in situ the evolution of the material during the SIS-ALD process on DSA-BCPs.

嵌段共聚物（Block-Copolymers, BCPs）的直接自组装（Direct Self-Assembling, DSA，即DSA-BCPs）被视为突破现有自上而下加工方法空间分辨率极限的独有方案，兼具加工成本与能耗低廉的显著优势。该自下而上的制备方法基于两种共价键合聚合物的相反性质，二者可自发组装形成具有分子级临界尺寸的结构化图案。
为优化纳米结构化图案的最终性能并拓展该新兴技术的应用场景，基于原子层沉积（Atomic Layer Deposition, ALD）的顺序渗透合成（Sequential Infiltration Synthesis, SIS，简称SIS-ALD）近年来得以开发：当SIS-ALD应用于这类软质材料时，气态前驱体可依次渗透进入有机基体，既能够以聚合物为模板实现无机材料的沉积，同时可对基体自身性能进行调控。
明确SIS-ALD工艺参数与渗透后材料的最终性能及综合表现之间的内在关联，是制备具备最优结构、力学与电学性能的功能材料，进而实现实用化功能器件的核心前提。然而目前，对该工艺机理的全面解析与材料性能的详尽表征，仍未跟上不断拓展的制备能力的发展步伐。
为此，本研究将在NCD-SWEET光束线开展纳米结构化DSA-BCPs的SIS-ALD过程中原位掠入射小角X射线散射（Grazing Incidence Small-Angle X-ray Scattering, GISAXS）测量，此举不仅可获取TiO₂的SIS-ALD过程动力学信息，还可揭示不同工艺条件下支撑聚合物的形貌演变以及无机材料的共形沉积特征。
具体实验将依托ALBA同步辐射装置中近期搭建的ALD反应器开展，该反应器专为适配不同光束线（如NCD-SWEET与NOTOS）而设计，可实现对DSA-BCPs材料表面SIS-ALD过程中材料演化行为的原位实时监测。