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 with a mirror mode of operation, a method for operating a multiple particle beam system with a mirror mode of operation and an associated computer program product are disclosed. The multiple particle beam system can be operated in different mirror modes of operation which allow the multiple particle beam system to be inspected and recalibrated thoroughly. A detection system configured to operate in a first detection mode and/or in a second detection mode is used for the analysis.
1 . 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.
2 . The multiple particle beam system of claim 1 , wherein the sample region voltage supply is configured to apply a variable voltage to a sample stage on which the sample is placed.
3 . The multiple particle beam system of claim 1 , wherein the controller is configured so that the multiple particle beam system alternates between the normal mode of operation and the mirror mode of operation.
4 . The multiple particle beam system of claim 1 , wherein the detection system is configured to achieve the first and second detection modes based exclusively on different controls of the detection system by the controller.
5 . The multiple particle beam system of claim 1 , wherein the detection system comprises first and second detection units, the first detection unit is controlled by the controller in the first detection mode, and the second detection unit is controlled by the controller in the second detection mode.
6 . The multiple particle beam system of claim 5 , wherein at least one of the following holds:
the first detection unit comprises a particle detection unit and a light detection unit; and
the second detection unit comprises a particle detection unit and a light detection unit.
7 . The multiple particle beam system of claim 5 , wherein at least one of the following holds:
the first detection unit comprises an avalanche photodiode; and
the second detection unit comprises a CCD camera.
8 . The multiple particle beam system of claim 1 , wherein the micro-optical unit comprises at least one member selected from the group consisting of:
the multi-beam generator;
a multi-stigmator configured to individually adjust a stigmation of the first individual particle beams via the controller; and
a multi-focus correction mechanism configured to individually correct a focus of the first individual particle beams via the controller.
9 . The multiple particle beam system of claim 1 , wherein the multi-beam generator comprises a multi-lens array with a multi-aperture plate and with a counter electrode.
10 . The multiple particle beam system of claim 1 , wherein the multi-beam generator comprises a multi-aperture plate and a multi-deflector array.
11 . The multiple particle beam system of claim 1 , wherein the first particle optical unit comprises a global lens system.
12 . The multiple particle beam system of claim 1 , wherein the second particle optical unit comprises a projection lens system.
13 . The multiple particle beam system of claim 1 , wherein the controller is configured in so a way that, in the normal mode of operation and in the mirror mode of operation, the multi-beam generator is controllable in the same way.
14 . The multiple particle beam system of claim 1 , wherein the controller is configured in such a way that the control of the second particle optical unit is variable in the mirror mode of operation.
15 . The multiple particle beam system of claim 1 , wherein the controller is configured so that the control of the second particle optical unit is variable step-by-step in the mirror mode of operation, and the detection system is configured to make a recording in in each step.
16 . The multiple particle beam system of claim 1 , wherein the sample region voltage supply is configured to apply a variable voltage to a sample stage on which the sample is placed, and the controller is configured so that the multiple particle beam system alternates between the normal mode of operation and the mirror mode of operation.
17 . The multiple particle beam system of claim 16 , wherein the detection system is configured to achieve the first and second detection modes based exclusively on different controls of the detection system by the controller.
18 . The multiple particle beam system of claim 17 , wherein the detection system comprises first and second detection units, the first detection unit is controlled by the controller in the first detection mode, and the second detection unit is controlled by the controller in the second detection mode.
19 . The multiple particle beam system of claim 1 , wherein the sample region voltage supply is configured to apply a variable voltage to a sample stage on which the sample is placed, and the detection system is configured to achieve the first and second detection modes based exclusively on different controls of the detection system by the controller.
20 . The multiple particle beam system of claim 1 , wherein: the sample region voltage supply is configured to apply a variable voltage to a sample stage on which the sample is placed; the detection system comprises first and second detection units; the first detection unit is controlled by the controller in the first detection mode; and the second detection unit is controlled by the controller in the second detection mode.