Switchable liquid-crystal phase-shift mask for super-resolution photolithography based on Pancharatnam–Berry phase

We present a novel liquid-crystal-based phase-shift mask that utilizes the Pancharatnam–Berry phase for super-resolution photolithography. Using an automated maskless photoalignment technique, we pattern an azobenzene alignment layer in a nematic liquid-crystal cell to fabricate the mask. Since the image is formed by phase cancellation, the minimum feature size is not restricted by the diffraction limit; here, we obtain submicron features. The liquid-crystal properties of the cell allow the mask to be switched on and off by applying a voltage. The cost effectiveness and flexibility of this technique make it a promising new technology for photolithography.