METHODS FOR PROXIMITY EFFECT CORRECTION IN ELECTRON LITHOGRAPHY

A convenient and unambiguous way of characterizing the proximity effect is by use of the modulation transfer function. Six types of correction scheme are compared in this way, these being the use of high beam energies (> 20 keV), of low beam energies (< 20 keV), the use of multilayer resists, exact dose correction, "self-consistent" dose correction, and the application of correction exposures. The main conclusions drawn are that the use of high beam energies reduces the proximity effect significantly; that exact dose correction, in addition to performing better than the "self-consistent" technique, is computationally superior; and that correction exposures are effective, particularly in combination with other correction techniques.