We have studied low voltage (1-2 kV) electron beam lithography processes in PMMA and compared them to conventional high voltage processing. We looked at the deposited metal after liftoff as well as directly imaging resist profiles by atomic force microscopy. As expected, the proximity effects were greatly reduced. The forward scattering was found to increase at low voltage. The study of developed resist profiles showed that linewidth versus dose has a single Gaussian functional form, proving that forward scattering plays the major role in line broadening. The effective Gaussian linewidth is 60 nm at 1 kV in a 50 nm resist layer. Modeling of the lithographic process showed a significant increase in resolution and process latitude for thinner resists.
|Original language||English (US)|
|Number of pages||5|
|Journal||Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures|
|State||Published - 1999|
ASJC Scopus subject areas
- Condensed Matter Physics
- Electrical and Electronic Engineering