Static and Dynamic Wetting Characteristics of Nano-patterned Surfaces

In efforts to increase the scanning speeds of the current state-of-the-art IC chip manufacturing process, immersion lithography, the present work investigates the liquid wetting effects of oriented surface nanopatterns with varying depth. In this set of experiments, both static and forced dynamic contact line behaviors of two liquids were studied on two substrate materials imprinted with line-space nanopatterns of varying depth and hybridization (second tier of nano-posts). These experiments found a variety hydrophobic and hydrophilic behaviors, some of which deviate from conventional wetting theories. Specifically, the static and dynamic liquid contact angles are found to consistently depend on the depth of patterns with the same interfacial areas, and a surface with contact angle less than 90° was turned highly hydrophobic with the addition of patterns.