PROJECTION LENS ARRANGEMENT

摘要

A projection lens arrangement for a charged particle multi-beamlet system, the projection lens arrangement including one or more plates and one or more arrays of projection lenses. Each plate has an array of apertures formed in it, with projection lenses formed at the locations of the apertures. The arrays of projection lenses form an array of projection lens systems, each projection lens system comprising one or more of the projection lenses formed at corresponding points of the one or more arrays of projection lenses. The projection lens systems are arranged at a pitch in the range of about 1 to 3 times the diameter of the plate apertures, and each projection lens system is for demagnifying and focusing one or more of the charged particle beamlets on to the target plane, each projection lens system has an effective focal length in the range of about 1 to 5 times the pitch, and demagnifies the charged particle beamlets by at least 25 times.