Characteristic variation of exposure pattern in cell-projection electron-beam lithography

The characteristic variation of an exposure pattern with various optical pa rameters is calculated in a typical cell-projection lithography system by u sing an electron trajectory simulation. The Coulomb interaction effect amon g electrons in the beam is calculated which determines the pattern blur at the wafer surface. The acceleration voltage is 50kV, the exposure pattern i s a series of line and space, and the field size is 5 mum x 5 mum. As the b eam current density varies from 2 to 13 A/cm(2) at the specimen surface, th e pattern blur is evaluated in parameters of (1) the probability of electro ns 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, a s the line width varies from 0.13 to 0.2 mum.