Influence of secondary electrons in high-energy electron beam lithography

Abstract

The effect of secondary electrons in electron beam lithography is investigated based on a technique called point exposure distribution measurements. This technique involves printing a series of dots at different exposure doses using a high contrast electron beam resist. The experimental results indicate that the secondary electrons are the most likely cause for exposure events. The secondary electrons generated due to forward scattering also limit the highest achievable resolution. An analytical model is developed here based on the physics governing secondary electron generation and transport. The model is able to predict the dependence of dose on the observed diameter to within a reasonable accuracy. The experimental results were verified with the model at both 100 and 50 keV.