Implementation method for three- beam laser interference lithography

This paper analyzes the influence of beams spatial deviation on multibeam interference pattern. The pattern obtained by three beams is shown to be more stable on the whole surface compared with that obtained by four beams. In experiments, the He- Cd laser beam was divided to three beams which were rotationally symmetric and then the three beams were used to expose the photo- resist. The honeycomb lattice with a period of 600 nm and a height of 350 nm was fabricated. The measured data demonstrate that the energy distribution is more uniform and stable by using three- beam interference, which can reduce the accuracy demand of the optical light path for laser interference lithography.