UV curing nanoimprint is demonstrated for high aspect ratio gratings fabrication based on SU-8 for nanophotonics and
biochemical applications. The defects, which are caused by stress and friction between mold and resist and air bubbles
are key issues. To eliminate the defects, the process parameters, such as imprinting pressure, baking time and demolding
temperature, are optimized. SU-8 grating with 150nm in width and 1.5µm is presented with good uniformity in large area
using Si template fabricated by non-switching DRIE process. The process could find broader applications in the
manufacture of biochemical devices and nanophotonic structures.
Direct thermal bonding approaches are especially desirable as they allow formation of enclosed microchannels with
uniform surfaces composed entirely of the same polymeric material. It is often believed that the main phenomenon
involved during thermal bonding is a chain entanglement of the polymers over the boundary. If the temperature is too
high and/or the application of the force is too long then the polymer will flow and refill the channels caused by capillary
forces, called as roof filling phenomenon. In order to understand this process more fully, we describe an experimental
method for characterizing the roof filling rate inside a microchannel by measuring the polymer marching velocity or
position of a capillary meniscus during thermal bonding. 1D nanochannels was fabricated succesfully and the vertical
dimension was well controlled according to the top filling mechnism.
A number of current and future optical and optoelectronic devices require the creation of structure in HfO2 film. The reactive ion beam etching of HfO2 film and photoresist mask in Ar/CHF3 gas mixture was examined as a function of ion energy, discharge composition and ion beam incident angle. The details of etch rate have been interpreted in terms of mechanism of etching. The etch rate has shown a square root dependence on ion energy and variation versus incidence angle. The CHF3- plasma produced some chemical enhancement in HfO2 film etching. Compared with pure argon etching, better selectivity and higher fidelity pattern transfer were achieved with Ar/CHF3 for HfO2 film over photoresisit mask. The AFM scans of etched HfO2 film by tapping mode showed good surface quality.