A new Monte Carlo simulation including secondary electron generation has been performed to study energy dissipation in electron beam lithography. The simulation of inelastic scattering is calculated from the model of the generalized oscillator strength density distribution determined by a set of resonance energies and oscillator strengths. Varying the polymethylmethacrylate film thickness, the energy dissipation profiles for various electron beam energies are evaluated. The effects of backscattered electrons from the silicon substrate and secondary electrons are studied with respect to film thicknesses and electron beam energies. The backscattered electrons from the Si substrate broaden the profile, especially near the bottom layer, and the secondary electrons broaden the profiles over the whole film.