Patent ID: 8748842

Claim:
An electrostatic lens array comprising: multiple substrates spaced from each other by intervals, each of the multiple substrates having an aperture for passing therethrough a charged particle beam, wherein with respect to a travelling direction of the charged particle beam, a peripheral contour line formed by any one of surfaces of the multiple substrates other than an upper surface of a most upstream substrate and a lower surface of a most downstream substrate has a protruding portion protruding from a peripheral contour line of both of the upper surface of the most upstream substrate and the lower surface of the most downstream substrate, wherein a position of the protruding portion is defined by a position regulating member, whereby parallelism is adjustable so that a surface including the protruding portion is parallel to a surface to be irradiated with the charged particle beam after passing through the aperture, and wherein the position regulating member is in contact with the protruding portion.