Resolution and linewidth tolerances in electron beam and optical projection lithography

In order to understand the practical limits of electron beam direct-write and optical projection lithography techniques in device fabrication with micrometer and submicrometer geometries, we have exercised two computer simulation programs to estimate resolution limits and linewidth control. Latent image contrast and developed resist thickness contrast were calculated as a function of line-array spatial frequency. The linewidth tolerances were calculated by varying exposure, development time, focusing, line/space Pattern, resist thickness, etc. These simulation results indicate that the lithographic performance of the two techniques using state-of-the-art exposure tools are comparable at 1-µm dimensions. Some relevant experimental data also are presented.