Abstract: A method of writing a pattern on a substrate by a deflectable electron beam, in particular a pattern containing very fine features such as nanostructures, is carried out by dividing the pattern into at least two fields of differing size (15, 17) which are arranged one inside the other and have a common center (18) arranged at the central axis of the beam at which the beam has an undeflected setting, with the finer or finest pattern features contained in the inner field (15). The pattern is written by keeping the substrate stationary and writing the two fields in succession with a change in writing resolution of the beam on transition from one field to the next such that a finer step size is used for an inner field than for an outer field.