Radiation-sensitive oxo-hydroxo metal clusters have recently set a new standard for nanopatterning performance at single-digit nm resolution. Compared with conventional polymer photoresists, these clusters have radii that are 3-4 times smaller, which contributes to high resolution and small line-edge roughness. These performance features are achieved without sacrificing sensitivity. Among the cluster systems studied to date, organo tin species have attracted special interest because of their high EUV absorption cross sections, high radiolytic efficiencies, and high-resolution patterning performance. Consequently, they may support high-volume semiconductor manufacturing. Few studies, however, have described the properties of the solution precursors, the as-deposited cluster films, and the patterning mechanism. Herein, we describe findings from studies of the commercially available tin material, n-butyltin oxide hydroxide (n-BuSnOOH), focusing on a 2-heptanone precursor solution and the films deposited from it. We study solution speciation via NMR, X-ray diffraction, and SAXS and the films by AFM, XPS, TOF-SIMS, and FTIR. The n-BuSnOOH precursor consists primarily of a unique tin-capped, sodium-centered Keggin ion. Films studies reveal uniform morphologies, smooth surfaces, and details of compositions and chemical states. UV exposure experiments demonstrate radiolytic cleavage of the Sn-C bond, which leads to loss of the butyl group and cluster condensation.

Characterization of n-butylSnOOH for nanopatterning: Solution precursor and film

253rd National Meeting (2017)

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