Patent ID: 6614151
Filing Date: 2003-09-02
Classification: H01J

Abstract:
Apparatus for deflecting and focusing a charged particle stream by injecting the stream between a first pair of symmetrical deflection plates, comprising:a particle source, the particle source operative to aim the particle stream in a substantially undeflected condition at a position offset from a position equidistant between the first pair of symmetrical deflection plates, the offset position being at a predetermined location based upon stream deflection and stream offset characteristics, wherein the predetermined location comprises a vicinity of an inflection point on a deflection versus offset curve; at least one deflection stage disposed prior to a defining aperture, the at least one deflection stage and defining aperture to successively bend the particle stream and filter the particle stream to reduce an electron energy spread thereof; a variable quadrupole and focus lens disposed prior to deflection, the variable quadrupole and focus lens to dynamically adjust for particle stream astigmatism and focus the stream; and a target disposed substantially orthogonal to the particle stream, the stream to impact the target.