Enhanced optical microlithography with a Fabry-Perot-based spatial filtering technique

A coherent multiple imaging technique for use in optical microlithography w as studied. The technique involves placing a thin Fabry-Perot etalon betwee n the mask and the projection lens of an optical stepper. An optical lithog raphic computer simulation tool, Prolith/2, was used to evaluate the aerial image profile obtained for extended mask structures such as typical contac t hole arrays and line-space patterns used in integrated circuit fabricatio n. Additionally,a set of experimental studies were performed to validate th e simulation results. Enhancement of both resolution and depth of focus can be obtained simultaneously with appropriate etalon parameters. (C) 2000 Op tical Society of America.