APPARATUS AND METHOD FOR INSPECTING A SURFACE OF A SAMPLE
First Claim
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, anda 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
1 Assignment
0 Petitions
Accused Products
Abstract
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.
20 Citations
27 Claims
-
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 - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. Method for inspecting a surface of a sample comprising the steps of:
-
generating an array of primary charged particle beams using a multi beam charged particle generator; focusing the primary charged particle beams into a first array of separated spots in an intermediate plane, using a first lens system; directing the primary charged particle beams from the intermediate plane towards the sample surface using a second lens system and focusing all primary charged particle beams into a second array of individual spots on the sample surface using an electromagnetic or electrostatic objective lens which is common for at least the primary charged particle beams; 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 intermediate plane using said second lens system; and detecting said backscattered charged particles using 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. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
-
Specification