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We present dynamic plowing nanolithography on polymethylmethacrylate films, performed with a scan-linearized atomic force microscope able to scan up to 250 μm with high resolution. Modifications of the surface are obtained by plastically indenting the film surface with a vibrating tip. By changing the oscillation amplitude of the cantilever, i.e., the indentation depth, surfaces can be either imaged or modified. A program devoted to the control of the scanning process is also presented. The software basically converts the gray scale of pixel images into voltages used to control the dither piezo driving cantilever oscillations. The advantages of our experimental setup and the dependence of lithography efficiency on scanning parameters are discussed. Some insights into the process of surface modifications are presented.
Beyond measuring the topography of surfaces, scanning force microscopy (SFM) has proved to be valuable both for mapping of various materials properties and for modifying surfaces via lithography techniques. Thus, SFM has gained relevance as a surface analysis technique as well as a tool for nanoscale engineering purposes. Different kinds of tip-sample interactions are exploitable, e.g. mechanical, thermal and electrical ones. Owing to its versatility, SFM has found plenty of applications in polymer science. Among others, the examples reported on in this review article encompass issues related to commodity polymers, various polymer-based composites, polymer blends, or ferroelectric polymers. For instance, stiffness imaging is elucidated as a technique for detecting interphases occurring in composites with inorganic fillers. The described applications are mainly related to mechanical and electrical tip-sample interactions. The respective fundamentals are outlined as well as some aspects of the measurement of materials contrasts. The presented techniques of nano-scale modification are a dynamical sort of plowing lithography and electrical poling, both performed by means of SFM-probes.
Ti:sapphire laser pulses of 130 fs and 800 nm were focused on 3.2-7m-thick TiN films by a 60-mm focal length lens in air. The morphology of the ablated areas generated by laser pulses at a fluence slightly above the ablation threshold was characterized in dependence on the pulse number by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The cavity profiles, depths, diameters, and volumes were quantitatively evaluated by AFM. The polarization state of the laser light is discussed as a further parameter, in addition to fluence and pulse number, that influences and controls the ablation precision of these materials. It was observed that circularly polarized radiation enhances the average ablation rates and reduces the roughness in the cavities by a factor of 2-3 as compared to linearly polarized radiation of the same incident laser fluence. Special attention was paid to the interfacial region between the coating and substrate. Ultrashort-pulse laser drilling into the Si substrate revealed the generation of columnar features which even may surmount the original coating under laser conditions.