Wafer level silicon mould fabrication and imprinting of high density microstructures

Wafer level mould fabrication and its imprinting technology are of great interest for cost effective mass fabrication of nano or microsized patterns. Although the process for making a silicon mould involves only several steps such as photolithography, deep reactive ion etching (DRIE) and nanoimprinting, there are still many issues to be overcome in order to achieve uniformly imprinted patterns on the whole wafer. Taking a 4″ wafer full of high density 3 × 3 μm squares with a depth of 10 μm as an example, this paper investigates the pitfalls in silicon mould fabrication and imprinting, and provides feasible solutions as a good reference to researchers seeking to mass fabricate micron-sized patterns by thermal imprinting.

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► Wafer level high density silicon mold fabrication and its subsequent imprinting are achieved.
► Particles on silicon wafer and photomask cause light interference which deforms lithography patterns.
► The micrograss generated in silicon DIRE can be eliminated by using thin photoresist AZ5214.
► Due to the high pattern density, the thermal imprinting time has to be prolonged to 5 h.