Reduction of exposing time in massively-parallel E-beam systems

Several writing methods were previously introduced for massively parallel electron-beam systems, e.g., single-row writing and multirow writing. A straightforward application of these methods for realizing nonuniform dose distributions often required for the proximity effect correction (PEC) including line/space patterns would turn off certain beams, sometimes all, selectively in several cycles. Consequently, the utilization of beams is reduced considerably. In this study, two different approaches to increasing the beam utilization and thereby reducing the exposing (writing) time are investigated, i.e., lowering the dose difference among the regions of a feature while implementing the PEC and utilizing the cycles with all the beams turned off. It has been shown that with these methods, the exposing time can be reduced significantly.