PREVAIL Alpha system: Status and design considerations

Abstract

An overview is given of the PREVAIL Alpha system program, a joint project of IBM and Nikon to develop a production-level electron project lithography system. The Alpha system program is based on the successful completion of an initial feasibility phase conducted by the IBM/Nikon alliance team and on the PREVAIL proof of concept results reported at EIPBN 1999. The electron beam column and associated electronics and software are under development at IBM’s Semiconductor R&D Center in East Fishkill, New York, while the high speed, high precision stages for both reticle and wafer as well as the overall systems architecture are being developed at Nikon’s facilities. A key architectural objective is the combination of leading edge stepper technology with state-of-the-art PREVAIL electron optics. The design of the electron optics is based on carefully balancing geometric aberrations and Coulomb interactions for optimum resolution at the required high beam current. Cornerstones of the design are the high emittance gun and the curvilinear variable axis lens concept developed for PREVAIL. Design considerations of the Alpha column are emphasized including a detailed treatment of space-charge lens aberrations.