Patent ID: 6878937
Filing Date: 2005-04-12
Classification: G01N,H01J

Abstract:
1. An apparatus for inspecting a substrate using charged particles, the apparatus comprising: an illumination subsystem configured to generate an incident charged-particle beam; an objective subsystem configured to receive the incident beam, to focus the incident beam onto the substrate, and to retrieve a scattered beam from the substrate; a projection subsystem configured to receive the scattered beam and to project the scattered beam onto a detector; and a beam separator coupled to and interconnecting the illumination subsystem, the objective subsystem, and the projection subsystem; wherein the beam separator is configured to receive the incident beam from the illumination subsystem, bend the incident beam towards the objective subsystem, receive the scattered beam from the objective subsystem, and bend the scattered beam towards the projection subsystem; and wherein the beam separator comprises a magnetic prism array including a central magnetic sector, inner magnetic sectors positioned outside the central sector, and outer magnetic sectors positioned outside the inner magnetic sectors.