New concept for high-throughput multielectron beam direct write system

A new multielectron-beam optical system with correction lens array (CLA) is proposed. The CLA is arranged between an electron source and reduction optics. The CLA can generate plural intermediate images of the electron source as a multisource, and moreover can compensate field curvature and distortion of the reduction optics. The proposed system was designed and optimized through simulations. The specifications are field size of 250 mum square, convergence beam angle of 10 mrad, 64x64 beams, individual beam size of phi 25 nm, accelerating voltage of 50 kV, and demagnification ratio of 50. The practical resolution for various resist processes is estimated considering the Coulomb interaction effect, and the throughput is simulated. The proposed system offers the possibility of "maskness" electron beam lithography with throughput in excess of 50 wafers/h (8 in.) for the International Technology Roadmap for Semiconductors (ITRS) 100 nm and 70 nm nodes at 3 muC/cm(2) resist sensitivity. (C) 2000 American Vacuum Society. [S0734-211X(00)07206-1].