Fabrication and inspection of two-dimensional lattice structures in thin polymer films have been carried out using a computer-controlled scanning electron microscope (CCSEM). Periods of 0.2 μ are quite regular, finer resolutions show some irregularities possibly due to film instabilities. Using the CCSEM permits great flexibility, and using thin films eliminates the problem of backscattered electrons from the substrate, which severely limits the resolution of periodic structures fabricated on a solid substrate. These structures should be useful in integrated optics, and may be used as x-ray lithography or evaporation masks.