Reversed order hybrid lithography of T-NIL and UVL

For a simple and low-cost preparation of e.g. sensors featuring large areas of nano-scaled line fields connected to micron-sized contacts we propose hybrid lithography of thermal nanoimprint and optical lithography in a reversed order. In the reversed order process the first step is lithography, followed by thermal nanoimprint and finally development. When the imprint is performed into a positive tone resist with a minimum residual layer remaining, any residual polymer is cleared during development, thus avoiding an additional dry etch step. This allows easy metal definition by sputtering and lift-off directly after development. Compared to a conventional sequence, the reversed order process allows higher imprint temperatures and reduces the exposure doses needed substantially, thus improving the quality of the imprint and of the lithography step as well. Line fields of several millimetres length could be successfully prepared. Based on the results obtained a novel approach for low-cost sensor preparation is proposed.

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► Combination of UVL and T-NIL in one single positive tone resist layer.
► Hybrid lithography in reversed order, first UVL then T-NIL.
► nm-pattern definition by T-NIL, μm-pattern by UVL.
► Lift-off without residual layer removal by dry etching.