Multiple particle beam system with a mirror mode of operation, method for operating a multiple particle beam system with a mirror mode of operation and associated computer program product

A multiple particle beam system, comprising:

• a particle source configured to generate a first charged particle beam;
• a micro-optical unit comprising a multi-beam generator, the micro-optical unit configured to generate a first field of a multiplicity of charged individual particle beams from the first charged particle beam;
• a first particle optical unit having a first particle optical beam path, the first particle optical unit configured to direct the individual particle beams at a sample and/or in a direction of a sample so that the first particle beams strike the sample at locations of incidence and/or reach reversal locations upstream of the sample to define a second field;
• a detection system;
• a second particle optical unit having a second particle optical beam path, the second particle optical unit configured to image second individual particle beams onto the detection system, the second individual particle beams emanating from:
• i) the locations of incidence in the second field onto the detection system;
• or ii) the reversal locations in the second field;
• a particle optical objective lens configured so that the first and second individual particle beams pass therethrough;
• a beam switch in the first particle optical beam path between the multi-beam particle source and the objective lens, the beam switch being in the second particle optical beam path between the objective lens and the detection system;
• a sample region voltage supply configured to provide an adjustable sample region voltage in the sample region;
• and
• a controller configured to control the micro-optical unit, the particle optical objective lens, the first particle optical unit, the second particle optical unit, the detection system and the sample region voltage supply,
• wherein:
• the detection system has first and second detection modes;
• in the first detection mode, the second individual particle beams are imaged on detection regions of the detection system which form a third field;
• in the second mode, a two-dimensional image is generated;
• the controller is configured to provide a normal mode of operation and a mirror mode of operation;
• in the normal mode of operation, the detection system is operated in the first detection mode;
• in the normal mode of operation, the sample region voltage is set so that the first individual particle beams are incident on the sample and release from the sample a multiplicity of secondary particles in the form of second individual particle beams, the secondary particles being imaged on the detection system after passing through the second particle optical unit;
• in the mirror mode of operation, the detection system is operated in the first and/or in the second detection mode;
• and
• in the mirror mode of operation, the sample region voltage is set so that at least some of the first individual particle beams are not incident on the sample but are reflected as second individual particle beams, the second individual particle beams being imaged on the detection system after passing through the second particle optical unit, and
• wherein:
• the detection system is operable in the second detection mode in the mirror mode of operation;
• in the mirror mode of operation, the sample region voltage is settable via the controller so that the first individual particle beams are not incident on the sample but are reflected as second individual particle beams;
• in the mirror mode of operation, the second individual particle beams are imageable on the detection system after passing through the second particle optical unit;
• and
• the controller is configured so that, in the mirror mode of operation, the multi-beam generator is switched off.