Characteristic Variation of Exposure Pattern in Cell-Projection Electron-Beam Lithography

Abstract

The characteristic variation of an exposure pattern with various optical parameters is calculated in a typical cell-projection lithography system by using an electron trajectory simulation. The Coulomb interaction effect among electrons in the beam is calculated which determines the pattern blur at the wafer surface. The acceleration voltage is 50 kV, the exposure pattern is a series of line and space, and the field size is 5 µm×5 µm. As the beam current density varies from 2 to 13 A/cm2 at the specimen surface, the pattern blur is evaluated in parameters of (1) the probability of electrons to be in the designed pattern, (2) the full width at half maximum and (3) the contrast of the electron density distribution at the wafer surface, as the line width varies from 0.13 to 0.2 µm.