Stamp design towards instability-induced 3D patterning

• 5 μm high polymeric bridges induced by a temperature difference.
• Silica particles as spacers between stamp and substrate.
• Rough estimation of mechanical properties of silica particles.

Instability-induced pattern formation is easily realized during thermal nanoimprint when a temperature difference is provided between stamp and substrate. The use of this effect for pattern definition requires spacers between stamp and substrate to install a gap of definite height. We test the use of silica particles to serve as spacers with variable height for such an approach. Then, there is no need to prepare stamps with a specific design especially for this purpose, as any stamp available can be used. It turns out that the silica particles are not ideally suited to serve as reliable spacers – they are too soft, when Si stamps are used, but too hard when replica stamps made from OrmoStamp are used. The experiments allow to roughly estimate the mechanical properties of the particles. Nonetheless, it is demonstrated that a formation of isolated polymeric bridges of 5 μm in height is feasible.

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