Signal separator for a multi-beam charged particle inspection apparatus

Use of a multi-beam charged particle column, for at least one of inspecting and imaging a surface of a sample, the multi-beam charged particle column comprising the steps of:

• creating multiple primary charged particle beams directed along trajectories towards the surface of the sample arranged on a sample holder using one or more emitters,
• focusing said multiple primary charged particle beams on said sample using an objective lens unit,
• detecting signal charged particles created upon incidence of the primary charged particle beams on said sample using a detector system, and
• using a combined magnetic deflection unit and electrostatic deflection unit arranged between the detector system and the sample holder, wherein the magnetic deflection unit comprises a plurality of strips of a magnetic of ferromagnetic material, wherein each strip of said plurality of strips is located next to a trajectory of a primary charged particle beam and within a distance equal to a pitch of the trajectories of the primary charged particle beams at the magnetic deflection unit, wherein the plurality of strips of a magnetic or ferromagnetic material establishes a magnetic field having field lines which cross a trajectory of the primary charged particle beams at an angle which is larger that 0 degrees, wherein the electrostatic deflection unit creates an electrostatic field acting at least on the primary charged particle beams, wherein the electrostatic deflection member provides an electrostatic field in a direction at least substantially perpendicular to the magnetic field of the magnetic deflection unit, and wherein the magnetic deflection unit and the electrostatic deflection unit are arranged spaced apart in a direction parallel to the trajectories of the primary charged particle beams.

A method for inspecting or imaging a surface of a sample, comprising the steps of:

• creating multiple primary charged particle beams directed along trajectories towards the surface of the sample arranged on a sample holder,
• focusing said multiple primary charged particle beams on said sample,
• establishing a magnetic field having field lines which cross a trajectory of the primary charged particle beams at an angle which is larger than 0 degrees, by using a magnetic deflection unit arranged between the detector system and the sample holder, wherein the magnetic deflection unit comprises a plurality of strips of a magnetic or ferromagnetic material, wherein each strip of said plurality of strips is located next to a trajectory of a primary charged particle beam and within a distance equal to a pitch of the trajectories of the primary charged particle beams at the magnetic deflection unit,
• establishing an electrostatic field acting at least on the primary charged particle beams, wherein the electrostatic field is configured to have field lines in the direction at least substantially perpendicular to the magnetic field, wherein a magnetic deflection unit for generating said magnetic field and the electrostatic deflection unit for the generating said electrostatic field are arranged spaced apart in a direction parallel to the trajectories of the primary charged particle beams, and
• detecting signal charged particles created upon incidence of the primary charged particle beams on said sample, by using a detector system.