
204 Biosensors Based on Nanomaterials and Nanodevices
Although conventional photolithography processing is high-throughput in production
facilities, its use for fabricating PhCs is limited by the feature sizes that can be achieved.
This disadvantage can be overcome by a novel technique called nanospherical-lens lithog-
raphy (Hou et al. 2005; Chang et al. 2012). On top of a photoresist layer, a monolayer of
polystyrene nanospheres is formed and when the surface is exposed to UV light, nano-
spheres act as lens and collimate the exposure energy. After the photoresist is developed,
the process of metal deposition, liftoff, and etching are performed ...