PREVAIL: Theory of the proof of concept column electron optics

The PREVAIL proof-of-concept (POC) system is described elsewhere in these proceedings. For theoretical as well as practical reasons, the operating conditions of POC were restricted to the special, albeit not necessarily optimum case, of the deflected beam following a particular trajectory in the lens doublet forming the backbone of the POC optics; this trajectory is referred to in optics as the "fundamental off-axis imaging ray." To provide guidance for and evaluation of its operation, the necessary computer simulation software was' developed in-house. The interaction between modeling and experimentation proved fruitful in achieving the primary objective, demonstration of feasibility of large-area reduction projection and beam scanning for next-generation lithography. Beyond that, the theory provides the means to investigate variations of the optics regarding configuration as well as setup, their impact on performance, and the direction for further improvements. (C) 1999 American Vacuum Society. [S0734-211X(99)14006-X].