Energy transfer between electrons and photoresist: Its relation to resolution

In the study of high-energy photon and electron lithography the photoresist has been treated as a uniform and isotropic medium. As dimensions become s maller and exposure fluctuation more noticeable, we cannot ignore the proce sses that happen at the molecular scale. Hence, it becomes important to und erstand how the energy is coupled from an exciting radiation to the various molecular components of a photoresist material. In this article, we presen t the first step in the development of such a model. We base the analysis o n the method of virtual quanta for the incoming electron, and use the diele ctric function response theory to describe the medium. The results correctl y describe the decreasing strength of the interaction on the electron energ y, and yield an estimate of approximate to2-3 nm for an average interaction distance. A simple Monte Carlo simulation is implemented to verify the eff ect of the fluctuations due to the virtual quanta on a line edge. (C) 2000 American Vacuum Society. [S0734-211X(00)03706-9].