Abstract: The invention relates to a charged particle optical system comprising a beamlet generator for generating a plurality of charged particle beamlets, an electrostatic deflection system for deflecting the beamlets, and a projection lens system for directing the beamlets from the beamlet generator towards the target. The electrostatic deflection system comprises a first electrostatic deflector and a second electrostatic deflector for scanning charged particle beamlets over the target. The second electrostatic deflector is located behind the first electrostatic deflector so that, during operation of the system, a beamlet generated by the beamlet generator passes both of the electrostatic deflectors. During operation of the first and second electrostatic deflectors the system is adapted to apply voltages on the first electrostatic deflector and the second electrostatic deflector of opposite sign.

Abstract: 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.

Abstract: The invention relates to a charged particle optical system comprising a beamlet generator for generating a plurality of charged particle beamlets, an electrostatic deflection system for deflecting the beamlets, and a projection lens system for directing the beamlets from the beamlet generator towards the target. The electrostatic deflection system comprises a first electrostatic deflector and a second electrostatic deflector for scanning charged particle beamlets over the target. The second electrostatic deflector is located behind the first electrostatic deflector so that, during operation of the system, a beamlet generated by the beamlet generator passes both of the electrostatic deflectors. During operation of the first and second electrostatic deflectors the system is adapted to apply voltages on the first electrostatic deflector and the second electrostatic deflector of opposite sign.

Abstract: A charged particle multi-beamlet system for exposing a target using a plurality of beamlets. The system comprises a first plate having a plurality of holes formed in it, with a plurality of electrostatic projection lens systems formed at the location of each hole so that each electron beamlet passes through a corresponding projection lens system. The holes have sufficiently uniform placement and dimensions to enable focusing of the beamlets onto the surface of the target using a common control voltage. Preferably the electrostatic projection lens systems are controlled by a common electrical signal to focus the electron beamlets on the surface without correction of the focus or path of individual electron beamlets.

Abstract: 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.

Abstract: A charged particle multi-beamlet system for exposing a target using a plurality of beamlets. The system comprises a first plate having a plurality of holes formed in it, with a plurality of electrostatic projection lens systems formed at the location of each hole so that each electron beamlet passes through a corresponding projection lens system. The holes have sufficiently uniform placement and dimensions to enable focusing of the beamlets onto the surface of the target using a common control voltage. Preferably the electrostatic projection lens systems are controlled by a common electrical signal to focus the electron beamlets on the surface without correction of the focus or path of individual electron beamlets.