Charging Effects From Electron Beam Lithography

This paper discusses initial results from a study of pattern placement errors due to substrate charging in fixed spot direct write electron beam systems. Experimental results obtained from small crosses written with 20 keV electrons near large pads indicate charging errors of 0.2microns can occur over 1 mm away from the pad. 

We present a simple theory that describes the placement errors for large cross-pad separations. The theory suggests that the substrate-electron interaction is strong and long range. Finally we show how 50 keV electrons effectively reduce charging effects.