Elam Jeffrey W, Biswas Mahua, Darling Seth B, Yanguas-Gil Angel, Emery Jonathan D, Martinson Alex B F, Nealey Paul F, Segal-Peretz Tamar, Peng Qing, Winterstein Jonathan, Liddle J Alexander, Tseng Yu-Chih
Argonne National Laboratory, Argonne, IL 60439, USA.
University of Chicago, Chicago, IL 60637, USA.
ECS Trans. 2015;69(7):147-157. doi: 10.1149/06907.0147ecst.
Sequential infiltration synthesis (SIS) is a process derived from ALD in which a polymer is infused with inorganic material using sequential, self-limiting exposures to gaseous precursors. SIS can be used in lithography to harden polymer resists rendering them more robust towards subsequent etching, and this permits deeper and higher-resolution patterning of substrates such as silicon. Herein we describe recent investigations of a model system: AlO SIS using trimethyl aluminum (TMA) and HO within the diblock copolymer, poly(styrene-block-methyl methacrylate) (PS-b-PMMA). Combining in-situ Fourier transform infrared absorption spectroscopy, quartz-crystal microbalance, and synchrotron grazing incidence small angle X-ray scattering with high resolution scanning transmission electron microscope tomography, we elucidate important details of the SIS process: 1) TMA adsorption in PMMA occurs through a weakly-bound intermediate; 2) the SIS kinetics are diffusion-limited, with desorption 10× slower than adsorption; 3) dynamic structural changes occur during the individual precursor exposures. These findings have important implications for applications such as SIS lithography.
顺序浸润合成（SIS）是一种源自原子层沉积（ALD）的工艺，其中通过对气态前驱体进行顺序的、自限性的曝光，将无机材料注入聚合物中。SIS可用于光刻，以硬化聚合物抗蚀剂，使其对后续蚀刻更具耐受性，这使得诸如硅等衬底能够进行更深且更高分辨率的图案化。在此，我们描述了一个模型系统的近期研究：在二嵌段共聚物聚（苯乙烯 - 嵌段 - 甲基丙烯酸甲酯）（PS - b - PMMA）中使用三甲基铝（TMA）和H₂O进行AlO SIS。结合原位傅里叶变换红外吸收光谱、石英晶体微天平以及同步加速器掠入射小角X射线散射与高分辨率扫描透射电子显微镜断层扫描，我们阐明了SIS过程的重要细节：1）TMA在PMMA中的吸附通过弱结合中间体发生；2）SIS动力学受扩散限制，解吸速度比吸附慢10倍；3）在单个前驱体曝光期间发生动态结构变化。这些发现对诸如SIS光刻等应用具有重要意义。
