A reproducible wafer-scale method to obtain 3D nanostructures using a low-budget lithography tool is investigated. This method, called corner lithography, explores the conformal deposition and the subsequent timed isotropic etching of a thin film in a 3D shaped silicon template. Moreover, it offers sub-micron lithography in wafer scales that allows wide range of miniaturization of nano devices, shich are uniform and compatible with geometrical expectation. The technique leaves a residue of the thin film in sharp concave corners, which can be used as structural material or as an inversion mask in subsequent steps. Corner lithography is demonstrated based on a theoretical foundation including a statistical analysis that enables the construction of ries, slits and dots into versatile three-dimensional structures. The potential of corner lithography is studied by fabrication of functional 3D components, in particular i) novel tips containing nano-apertures at or near the apex for AFM-based liquid deposition devices, ii) novel 3D nanowire pyramid as scanning probe for atomic force microscopy, and iii) a novel particle or cell trapping device using an array of nanowire frames. The use of these arrays of nanowire cages for capturing single primary bovine chondrocytes by a droplet seeding method is successfully demonstrated, and changes in phenotype are observed over time, while retaining them in a well-defined pattern and 3D microenvironment in a flat array. Moreover, an innovative method that is called “repeated corner lithography‿ is introduced which gives higher resolution and employs to obtain sub-30 nm apertures and pyramidal nanowires, while maintaining the mechanical stability of the micron structures.
|Award date||12 Nov 2014|
|Place of Publication||Enschede|
|Publication status||Published - 12 Nov 2014|