The minimum necessary exposure time for a certain area, at a given exposure dose, can be calculated by the following correlation:
Area * dose = Duration of exposure * beam current
In the minimum writing time, the time expenditure for movements of the substrate mount (fade-out times) and respectively corrections and adjustments during writing are not taken into consideration. Due to the required time expenditure (writing a sample with sub-100nm solution on a wafer using a not particularly sensitive resist (PMMA) already takes several days), direct writing procedures with one beam only are not suited for mass production. For a significant reduction of writing times and thus a more economic performance, there is research/ development of facilities which allow the parallel application of several electron beams (multiple beam writers, mappers).
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