Talbot lithography using aperiodic structures

We propose a phase-mask lithography scheme employing the Talbot field generated from aperiodic structures. In this approach, a 1-dimensional (1D) grating with fixed period and spatially varying duty-cycle is used to generate a 3-dimensional (3D) aperiodic intensity pattern, which can then be recorded by photoresist. Simulated intensity pattern using finite-difference time-domain (FDTD) method is used to design and optimize the duty-cycle profile of the aperiodic 1D grating. The proposed phase-mask can be patterned using electron-beam lithography directly on a fused silica substrate, and then used to fabricate complex aperiodic structure in direct contact exposure.