A new low-cost fabrication method of SU-8 micro-nano channels and needle tip in electro-hydrodynamic jet chips

摘要

Electro-hydrodynamic (EHD) jets are widely used for direct writing of micro and nano structures. However, the application of an EHD jet is limited by its high-cost production process. To overcome the drawbacks mentioned above, a new fabrication method of polymer EHD jet needle is proposed in this paper. A silicon nano mold is firstly produced by inclined deposition technique, and a micro-nano PDMS mold is developed by casting double-layer PDMS on the silicon nano mold with a photomask film between the two PDMS layers. Using the micro-nano PDMS mold, a micro-nano needle can be fabricated in SU-8 photorcsist layers by thermal nanoimprinting and ultraviolet lithography. In the manufacturing process, the exposure parameters and the thermal bonding parameters were optimized. The final chip consists of micro-nano channels, in which the nano channels are 380 nm in width and 72 nm in depth. The chip is tested with fluorescent dye, indicating that the micro-nano channels are fabricated without blockage or leakage. This low-cost fabrication method of micro-nano needle may have a great contribution to direct write-on-demand nano-patterning technology.