Apparatus and method for inspecting a surface of a sample

摘要

The invention relates to an apparatus and method for inspecting a sample. The apparatus comprises a generator for generating an array of primary charged particle beams (33), and a charged particle optical system with an optical axis (38). The optical system comprises a first lens system (37, 310) for focusing all primary beams (33) into a first array of spots in an intermediate plane, and a second lens system (313, 314) for focusing all primary beams (33) into a second array of spots on the sample surface (315). The apparatus comprises a position sensitive backscattered charged particle detector (311) positioned at or near the intermediate plane. The second lens system comprises an electromagnetic or electrostatic lens which is common for all charged particle beams. Preferably the second lens system comprises a magnetic lens for rotating the array of primary beams (33) around the optical axis (38) to position the second array of charged particle spots with respect to the first array at an angle.

主权项

1. An apparatus for inspecting a surface of a sample, wherein the apparatus comprises a multi beam charged particle generator for generating an array of primary charged particle beams, and a charged particle optical system with an optical axis comprising:
a first lens system for focusing the primary charged particle beams into a first array of separated spots in an intermediate plane, and a second lens system for directing the primary charged particle beams from the intermediate plane towards the sample surface and which comprises an electromagnetic or electrostatic objective lens which is common for at least the primary charged particle beams for focusing all primary charged particle beams into a second array of individual spots on the sample surface, wherein the apparatus comprises a position sensitive backscatter charged particle detector positioned in or near the intermediate plane, wherein said detector comprises one or more through openings for passing said primary charged particle beams there through, and wherein said second lens system is arranged for projecting backscattered charged particles from the second array of individual spots on the sample surface into an array of backscattered charged particle spots on the detector.