PREVAIL Alpha system: Status and design considerations

An overview is given of the PREVAIL Alpha system program, a joint project o f IBM and Nikon to develop a production-level electron project lithography system. The Alpha system program is based On the successful completion of a n 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 a t 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 ove rall systems architecture are being developed at Nikon's facilities. A key architectural objective is the combination of leading edge stepper technolo gy with state-of-the-art PREVAIL electron optics. The design of the electro n optics is based on carefully balancing geometric aberrations and Coulomb interactions for optimum resolution at the required high beam current. Corn erstones of the design are the high emittance gun and the curvilinear varia ble axis lens concept developed for PREVAIL. Design considerations of the A lpha column are emphasized including a detailed treatment of space-charge l ens aberrations. (C) 2000 American Vacuum Society. [S0734-211X(00)02406-9].