Patent ID: 8835867
Filing Date: 2014-09-16
Classification: B82Y,H01F,H01J,H05K

Abstract:
1. A multi-axis magnetic lens, comprising: a pair of parallel magnetic conductor plates with a plurality of through holes in pairs therein, the pair of parallel magnetic conductor plates including an upper plate and a lower plate, wherein for each paired through holes, an upper through hole in the upper plate is aligned with a corresponding lower through hole in the lower plate; a plurality of magnetic cellular pillars in pairs inside the plurality of through holes with a plurality of first radial gaps in pairs respectively, each pair of magnetic cellular pillars forming an axial gap therebetween and having a plurality of through bores in pairs, wherein for each paired first radial gaps formed by each paired magnetic cellular pillars inside each paired through holes, a first upper radial gap is between an inner sidewall of the upper through hole and an outer sidewall of the upper magnetic cellular pillar inside the upper through hole, a first lower radial gap is between an inner sidewall of the lower through hole and an outer sidewall of the lower magnetic cellular pillar inside the lower through hole, wherein for each paired through bores inside said each paired magnetic cellular pillars, an upper through bore in the upper magnetic cellular pillar is aligned with a corresponding lower through bore in the lower magnetic cellular pillar, thereby forming a plurality of magnetic sub-lens group modules for focusing a plurality of charged particle beams respectively, wherein each magnetic sub-lens group comprises a plurality of magnetic sub-lenses, and paired upper and lower magnetic cellular pillars of each sub-lens group module respectively function as upper and lower pole-pieces of each sub-lens of said sub-lens group; and a common excitation coil located between the pair of parallel magnetic conductor plates for providing magnetic flux to the plurality of magnetic sub-lens group modules.