High-voltage shaped e-beam lithography

A high-voltage (100 kV) variable-shaped electron beam lithography system has been developed. With this system it is possible to improve the edge resolution in variable-shape lithography to better than 0.1 μm even at high beam currents. In addition the other advantages of high-voltage lithography such as reduced proximity effect, improved line width control in lithography over steps in the substrate, and better profiles on thick resist overlayers are also obtained. Experimental results are compared with simulation from a Monte Carlo based model of the electron column which predicts the benefits of working at higher beam voltage than the conventional 20 kV. Results are presented which show current profiles and exposures in resist of patterns with sizes from 5 μm×5 μm to ∼1 μm×1 μm with sub 0.1 μm resolution at beam voltages of 70 kV and greater while maintaining a beam current of >3 μA.