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• Random nanoholes on photoresist were produced at normal and near-normal incidence. • Tunable nanoholes can be tailored/replicated with deterministic ion beam parameters. • XPS analysis confirmed ion bombardment-induced graphitization of resist. • Results imply mass redistribution is critical in pattern formation. • Ion bombardment-induced nanoholes are potential nano-templates for pattern transfer. Random nanohole morphologies on a photoresist surface were produced spontaneously by ion bombardment, from normal to near-normal incidence. At an optimized ion energy, the critical parameters (diameter and depth) and uniformity of these nanoholes can be tailored with multi-ion parameters, including ion fluence (i.e. bombardment time), ion flux, and incidence angle. The temporal evolution of the nanohole structures, at normal incidence, showed growth and stabilization regimes. The mass redistribution effect and the distribution of energy deposition led to the transition from nanoholes to nanoripples, which were deduced from the crater shape evolution at low incidence angles. The incidence angle-dependent evolution of the crater shape (or rim) on the resist surface is consistent with the crater function simulation, and confirms the ion bombardment-induced surface atomic currents and mass redistribution. Finally, X-ray photoelectron spectroscopy characterization confirmed ion bombardment-induced decomposition, in particular, graphitization in the surface layer of the resist. [ABSTRACT FROM AUTHOR]

• Energy dependence of resist morphology under ion bombardment is demonstrated. • Light molecules in organic resist were enriched by ion bombardment. • Ion energy shows great potential for modulating chemistry and morphology. • Nanoholes were formed on organic resist in a wide ion energy range. • Morphology evolution is preliminarily explained using existing theoretical models. The energy dependence of nanostructures on a photoresist produced by ion bombardment (IB) under normal incidence is studied through atomic force microscopy and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). The energy-dependent morphology evolved from weak islands via nanoholes to a smooth surface on the resist; in particular, nanoholes were produced for a broad energy range of 300–550 eV. The enrichment of light components in the surface layer of the irradiated resist was illustrated owing to the strong decomposition of the photoresist by IB. The energy dependence of the morphologies is explained according to the ToF-SIMS characterization and the existing theoretical models of IB, which is an IB-induced synergy of chemical variation and sputtering. This study extends the IB in inorganic materials into an organic-multicomponent photoresist and provides new insights into the experimental evidence for nanoholes and possible parameters to improve the relevant theoretical model. [ABSTRACT FROM AUTHOR]