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Electrohydrodynamic (EHD) jet printing is a promising direct writing method to produce micro- and nano-scale dots due to its easy manipulation, high resolution, and low cost. The effect of printing conditions on the diameter of printed dots was widely studied by both experiments and simulations. However, positional precision is also important for EHD printing. There is no published work on numerical simulation for the trajectory analysis of the ejected droplet. In the present work, a finite element model was established to investigate the droplet trajectory. The influencing factors, such as nozzle size, nozzle angle, applied voltage, ink density, and charge number in one droplet, were considered during numerical simulation. The influence of influencing factors on the electric intensity, droplet speed, and deposition direction was analyzed. The proposed simulation model provides a useful tool to analyze the droplet formation process and optimize the printing parameters to improve the positional precision of EHD printing.

Micro–nanofluidic chips have been widely applied in biological and medical fields. In this paper, a simple and low-cost fabrication method for micro–nano fluidic chips is proposed. The nano-channels are fabricated by thermal nano-imprinting on an SU-8 photoresist layer followed by thermal bonding with a second SU-8 photoresist layer. The micro-channels are produced on the second layer by UV exposure and then thermal bonded by a third layer of SU-8 photoresist. The final micro–nano fluidic chip consists of micro-channels (width of 200.0 ± 0.1 μm and, depth of 8.0 ± 0.1 μm) connected by nano-channels (width of 533 ± 6 nm and, depth of 372 ± 6 nm), which has great potential in molecular filtering and detection.

Nano-imprint technology is a method of nano-pattern reproduction, has the characteristics of high resolution, high throughput, and low-cost. It can reduce the complexity and cost of the equipment while improving the resolution, which considered a promising industrial production technology. The key to nanoimprinting lies in the mold, and the quality of the mold directly determines the quality of the imprinted graphics. Here, a method for fabricating sub-100 nm concave 2D silicon nano-mold by side etch lift-off is proposed. The effects of different wet etching time and the metal deposition angle on the width of nanochannels were studied. The measurement result of dry etching shows that on the entire 4 inch silicon wafer, the width of the nanochannel varies by 4% and the depth by 2%. The width of the nanochannel between chips varies by 0.7%, and the depth variation is 1%. With this new method, high-precision and large-scale silicon nano-mold can be produced, which has great potential for realizing high-precision and low-cost manufacturing of nano devices.

Nano-fluidic devices have great potential in the applications of biology, chemistry, and medicine. However, their applications have been hampered by their expensive or complicated fabrication methods. We present a new and simple approach to fabricate low-cost two-dimensional (2D) nano-mold based on ultraviolet (UV) lithography and wet etching. The influence of UV lithography parameters on the width dimension of AZ5214 photoresist was investigated. With the optimized parameters of UV lithography, the width dimension of photoresist patterns had sharply decreased from microscale to nano-scale. At the same time, the influences of etching time on the over-etching amount of SiO2 film and nano-mold depth were also analyzed for further reducing the width of nano-mold. In addition, the effect of photoresist mesas deformation on the nano-mold fabrication was also studied for improving the quality of nano-mold. By the proposed method, trapezoid cross-sectional 2D nano-mold with different dimensions can be obtained for supporting varied applications. The minimum nano-mold arrays we fabricated are the ones with the dimensions of 115[Formula: see text]nm in top edge, 284[Formula: see text]nm in bottom edge, and 136[Formula: see text]nm in depth. This method provides a low-cost way to fabricate high-quality and high-throughput 2D nano-mold.

The lithography contact/proximity printing technique is widely used in the fabrication of microelectronic components, optical devices, and micro-fluidic chips. However, the fabrication of nano-sized structures requires high-cost equipment. This paper proposes a low-cost method to manufacture nanostructures by ultraviolet proximity exposing lithography through a microphotomask on a conventional lithographic aligner. The influence of exposure distance on photoresist pattern size is studied, and the standing wave effect on the photoresist layer is reduced by post-baking. This cost effective method can be widely applied to fabricate patterns with a nanofeature size.