A high speed EBL column designed to minimize beam interactions

Abstract

The writing strategy and electron optical aspects of the Perkin–Elmer AEBLE 150 EBL system are discussed. For a specific submicron EBL writing task, an ‘‘optimum’’ area for a variable shaped beam is derived. For specific column properties, an optimum gun brightness is chosen to image the shape at maximum beam interactions limited current. The writing system takes advantage of a continuously moving stage to allow a moderate scan field, exploiting in-lens deflection to use a very large aperture angle with a 2 mm field. Experimental data indicates a current density of 100 A/cm2 in rectangular or triangular shapes up to 2 μm in size. Edge resolution is less than 0.15 μm for shapes containing less than 1.5 μA of current. A series of beam profiles taken with a 300 ns exposure cycle shows that the deflection systems will support high speed lithography on insensitive resists.