We report the depth vs. exposure characteristics of poly(methyl methacrylate) (PMMA) in the vacuum ultraviolet (VUV) region from 59 to 128 nm. Calculated absorption coefficients of the PMMA are also presented. The depth of the features on the PMMA were in the range of 20-80 nm created by 1-50 mJ/cm2 exposures and were measured with an atomic force microscope (AFM). We found that the AFM can reliably measure depth differences of only 2 nm. The sensitivity of the AFM permits exposures to be reduced for high resolution microscopy and holography even in the case of highly absorbing films.

This work was sponsored by the National Science Foundation, and the U.S. Air Force Office of Scientific Research.