Patent ID: 10504683

Abstract:
Disclosed herein is charged particle beam device and a a method of operating a charged particle beam device, comprising forming a plurality of focused charged particle beamlets. Charged particles are directed from a charged particle source to a multi-aperture plate. A plurality of beamlets are passed through a plurality of apertures of the multi-aperture plate. The beamlets include an inner beamlet of charged particles and a plurality of outer beamlets of charged particles. The outer beamlets are focused to form a plurality of outer focal points on a virtual ring having a center along an optical axis, the outer beamlets subjected to a field curvature aberration, such that the virtual ring is axially displaced relative to a virtual focal point of an uncompensated inner beamlet. A compensated inner beamlet is focused to a compensated focal point. The inner beamlet is compensated to form the compensated inner beamlet; and the compensated focal point is coplanar with the virtual ring.