The Monte Carlo Simulation Of Electron Beam Lithography

The electron beam lithography (EBL) is of essential importance for the development of microelectronics technology. In recent years, the more interests have been focused on the low-energy EBL due to its many characteristics, and there are many problems to be studied in this field. In EBL, a key factor to dominate the exposure resolution is the proximity effect produced by the scattering of energetic electrons in resist. The quantitative description for the proximity effect requires knowledge of the distributions of energy dissipations in resist, which determines the proximity effect and exposure resolution in EBL. However, the theoretical studies on the distributions of energy dissipations in low-energy EBL have been seldom reported. For theoretical studies of EBL, it is a very important and effective approach to simulate the scattering processes of energetic electrons in solids by using Monte Carlo method. In this work, with the use of Monte Carlo method the simulations for the low-energy EBL in the range of incident energy E ≤ 5 keV have been performed. Mott cross-section is used to describe the elastic scattering of electron in solid, and the stopping power based on the dielectric response theory with exchange effect included and the Bethe stopping power modified by Joy and Luo are applied, respectively, for calculating the energy loss of electrons in PMMA. The distributions of energy dissipations in PMMA and the influence of the different theoretical stopping powers on the simulated distributions of energy dissipations have been studied and analyzed systematically.1. The depth distributions and radial distributions of the electron energy dissipations in PMMA film on Si substrate have been simulated and analyzed systematically for different beam energies and different PMMA film thicknesses. The simulated results indicates that the range of electron scattering in PMMA reduces rapidly with decreasing beam energy, which is the reason that the low-energy EBL is of the characteristics, such as small proximity effects, high exposure efficiency and less substrate damage. Also, it is shown that the contributions of the forward scattering electrons to the energy dissipations in PMMA can be remarkably affected by varying...