Simulation, Construction, and Testing of a Lloyd's Mirror Lithographic Interferometer

Fabrication of nanoscale highly periodic structures is a vital capability for research on quasicrystals, directional and specular selective emitters, and plasmonics. Laser interference lithography is a maskless lithography process capable of producing patterns with high periodicity over large areas, and is compatible with standard optical lithography processing. In this work, a Lloyd's mirror lithographic interferometer is simulated, built, and tested. Featuring a HeCd CW laser at 325 nm, spatial lter, and vacuum stage, it is capable of generating patterns with a sub-100 nanometer half pitch, over a large area (approximately 8 cm²), with minimal distortion, in a single exposure; with 2D patterns possible using multiple exposures. The interferometer features a compact sliding enclosure, simple alignment and operation, and quick adjustments to the desired period. One-dimensional and two-dimensional patterns were generated and matched well with simulation.