DY-7 sub-0.1 micron EB lithography system

A scanning electron beam lithography system with a field size of 1 X 1 mm h as been built for the delineation of sub-0.1 mum patterns. The system compr ises a 30-kV LaB6 electron gun with a zoom lens arrangement of a condenser doublet. To minimize the aberrations, a combined magnetic focusing and defl ection system with prelens double deflection is adopted and optimized. To a void the often-appearing problem with multi-variable optimization process, i.e. the ultimate results depend on the initial values, a practical way is suggested. Instead of the conventional coil-winding deflector, a saddle coi l deflector consisted of electrodes fabricated by wire electron discharge m achining (WEDM) is employed to gain higher geometrical accuracy and lower i nductance. To increase writing speed and accuracy, we have developed a mult i-function pattern generator to perform the writing of trapezoids, polygons , circles, rings as well as rectangles directly through hardware. In additi on, a novel approach for linear and non-linear correction of patterns is in troduced to improve the scan accuracy. The system has been used to delineat e nanometer-scale patterns in both PMMA and ZEP 520 electronic resists on t hick Si substrates over a field size of 1 X 1 mm. A lithographic example wi th the system is shown. (C) 2001 Elsevier Science B.V. All rights reserved.