Electrodynamics of fast beam blankers

Performance characteristics of an advanced electron beam blanker for lithography are presented. Various electrodynamic effects are discussed, which must be eliminated to achieve high beam placement accuracy during and after blanking. These electric and magnetic field effects have been measured over six orders of magnitude in time. The fast beam jitter characteristic of transit time effects in a double‐deflection blanker is captured with nanosecond time resolution. Eddy current effects measured in the micro‐ to millisecond time domain are shown to be an inherent problem in earlier double‐deflection blanker designs. A consequence is beam misplacement after the unblank transition, which can be 0.05 μm even after 500 μs. Several examples of pattern artifacts in purposely underdeveloped resist are given to illustrate graphically the lithographic consequences of the eddy current effect. All of these electrodynamic effects have been addressed with a new ‘‘virtual ground’’ blanker design. The MEBES IV‐TFE maskmak...