Monte Carlo analysis of electron scattering in microstructure processes in the 0.2 μm region

Theoretical understanding of electron scattering phenomena is essential to the implementation of X-ray lithography. In this paper we theoretically investigate electron scattering effects in X-ray mask-making, by means of a subtractive process, in the 0.2 μm region. The results of Monte Carlo simulation are utilized in order to calculate radial absorbed energy distributions and resist development profiles with respect to some cases of practical interest. Relevant process variables are considered, such as electron-beam energy (10 to 30 keV) and spot sizes. The results show how, by choosing appropriate working conditions, high-resolution patterns can be obtained. Favourable process conditions are found at the low electron energy limit. However, it is shown that suitable electron-beam spot sizes are required in order to take fully advantage of the favourable properties of the scattering.