Patent ID: 8558191

Claim:
A charged particle beam lens comprising: a first electrode on a downstream side and a second electrode on an upstream side in a travelling direction of a charged particle beam, wherein each of the first electrode and the second electrode has a first through hole formed therein, through which the charged particle beam passes, the second electrode has a second through hole formed therein, through which the charged particle beam does not pass; a distance defining member provided between the first electrode and the second electrode, such that the first electrode and the second electrode are spaced away from each other; and a gap surrounded by the first electrode, the second electrode, and the distance defining member, wherein both the first through hole and the second through hole communicate to the gap, wherein a third through hole passes through the first electrode and the second electrode in the travelling direction of the charged particle beam, the third through hole being provided outside of the gap and not communicating to the gap.