Patent ID: 8003953
Filing Date: 2011-08-23
Classification: H01J

Abstract:
1. A multi-axis magnetic lens, comprising: a pair of parallel magnetic conductor plates with a plurality of charged particle beams passing through holes, wherein each hole in the upper plate of the pair of parallel magnetic conductor plates is aligned with the corresponding hole in the lower plate of the pair of parallel magnetic conductor plates; a plurality of magnetic insert rings, each magnetic insert ring inserted in each hole in each magnetic conductor plate and aligned with this hole; a plurality of gaps, each gap inserted between the outer sidewall of each magnetic insert ring and the inner sidewall of each hole in each magnetic conductor plate; wherein a plurality of sub-lens modules are formed, each sub-lens module includes a pair of the aligned holes in the upper magnetic conductor plate and the lower magnetic conductor plate, a pair of the magnetic insert rings respectively inserted in each of this pair of holes and the gaps between the inner sidewall of each of this pair of holes and the outer sidewall of each of this pair of magnetic insert rings, and the pair of the magnetic insert rings function as a pair of magnetic pole pieces of the sub-lens; and a common excitation coil, the coil provides magnetic flux to the plurality of sub-lens modules, wherein each sub-lens module focuses a charged particle beam.