Electron optical column for a multicolumn, multibeam direct-write electronbeam lithography system

Electron beam direct-write lithography systems are capable of meeting the r esolution requirements of all future ITRS nodes and have a significant cost of ownership advantage over masked technologies, but these systems typical ly have very poor throughput due to space charge limitations. Ion Diagnosti cs has developed a multicolumn, multibeam (MXM(TM)) direct-write system tha t circumvents the space charge limitations by spreading the electron curren t over the wafer. The resulting lithography system can achieve critical dim ensions of less than 100 nm with production throughputs greater than 60 waf ers per hour, independent of wafer size. Tn this article we describe the el ectron optical column used in this system. We have developed a novel, micro fabricated electron gun that produces 32 parallel electron beams that are i ndividually controlled and blanked and contain deflectors that allow the gu n optics to act as a perfect lens. Each column is 2 cm X 2 cm and can align and scan the 32 beams in parallel on the wafer. The wafer voltage is typic ally held at 50-100 kV, and backscattered electrons are collected for imagi ng and alignment information. Theoretical results and some performance resu lts for a prototype column are presented. (C) 2000 American Vacuum Society. [S0734-211X(00)03606-4].