Charged particle beam device

Abstract

Provided is a charged particle beam device capable of improving throughput by avoiding shading or distortion caused by charge differences among respective patterns. The charged particle beam device comprises: a scanning deflector that performs scanning with charged particle beams emitted from a charged particle source; a signal electron deflector that deflects the trajectory of signal electrons emitted from a sample; a detector that detects signal electrons obtained on the basis of the scanning with the charged particle beams; and a pull-up electrode for pulling up the signal electrons to the detector. The charged particle beam device has a calculation unit that, when capturing an image of a region that includes a plurality of patterns, determines an imaging condition such that the length measurement value distribution of the plurality of patterns becomes uniform, on the basis of a combination of at least two among irradiation current density, pull-up electric field, acceleration voltage, magnification, scanning method, and scan rotation, which are control parameters.

Description

charged particle beam equipment

[0001] The present invention relates to a charged particle beam device.

[0002] As semiconductor patterns become finer and more highly integrated, even slight differences in shape have an impact on the operating characteristics of devices, increasing the need for shape control. As a result, scanning electron microscopes (SEMs) used for semiconductor inspection and measurement are required to have higher sensitivity and accuracy than ever before. A scanning electron microscope detects electrons emitted from a sample, generates a signal waveform by detecting these electrons, and measures, for example, the dimension between peaks (pattern edges).

[0003] In recent years, extreme ultraviolet (EUV) lithography has been increasingly adopted as a technology for forming fine patterns of 10 nm or less on wafers. It has been discovered that random defects known as stochastic defects pose a challenge in EUV lithography. This has led to an increased need for full-surface wafer inspection, and inspection equipment is required to achieve higher throughput.

[0004] One way to increase inspection efficiency (throughput) is to inspect a wide area simultaneously using low-magnification imaging with a large current. Low-magnification observation requires imaging multiple patterns simultaneously, but it is known that the sample charge varies with each pattern. The effects of charging are pronounced, particularly deflecting the trajectory of signal electrons generated from the sample. This can lead to various phenomena that reduce inspection accuracy, such as image distortion, shading (uneven brightness), and contrast abnormalities. Furthermore, when imaging at low magnification, there are cases where images containing multiple patterns are captured in a single field of view. Because different patterns result in different sample charges, shading and distortion due to differences in charge among patterns are becoming an issue. Several charge control methods have been proposed to reduce the impact of sample charging on the signal electron trajectory.

[0005] For example, Patent Document 1 describes a charged particle beam irradiation method in which, in order to suppress non-uniform charging of a sample in which a pre-irradiation region contains multiple different materials or in which the pattern density varies depending on the position within the pre-irradiation region, the pre-irradiation region is divided into multiple regions and charged using beams with different beam irradiation conditions. This technique requires region division, which raises concerns about reduced throughput. Furthermore, there is no description of a method for imaging without pre-irradiation.

[0006] Furthermore, in Patent Document 2, when acquiring an image of an FOV (field of view), beam irradiation points are set at intervals. The deflector is controlled to scan the charged particle beam at a higher speed when irradiating a position on the sample between the irradiation points than when irradiating the charged particle beam at a position on the sample corresponding to each irradiation point (a position on the sample corresponding to each pixel where signal detection is performed). This describes a method for mitigating or controlling the effects of charging in a microscopic region within the FOV. Patent Document 2 describes charging differences in a microscopic region, but does not describe imaging including multiple patterns.

[0007] JP 2011-210509 A International Publication No. 2015-045498 A

[0008] In charged particle beam devices, when capturing images containing multiple patterns, shading and distortion caused by differences in charge between the patterns are an issue. Patent Document 1 proposes a method of dividing an area and creating images under different capturing conditions, but does not disclose a method of capturing images of different patterns simultaneously under conditions that prevent differences in charge. Patent Document 2 also proposes a method of avoiding charging in minute areas by adjusting the irradiation point and scanning speed, but does not disclose a method for capturing images containing multiple patterns. From the above, it is desirable to be able to capture images containing multiple patterns without pre-irradiation or area division, and to achieve this, simultaneous control of the charge of multiple patterns is necessary.

[0009] Therefore, the present invention provides a charged particle beam device that can avoid shading or distortion caused by differences in charging between patterns and improve throughput.

[0010] In order to solve the above problems, the charged particle beam device of the present invention includes a scanning deflector that scans a charged particle beam emitted from a charged particle source, a signal electron deflector that deflects the trajectory of signal electrons emitted from a sample, a detector that detects signal electrons obtained based on the scanning of the charged particle beam, and a pull-up electrode that pulls up the signal electrons to the detector, and when imaging an area including multiple patterns, has a calculation unit that determines imaging conditions such that the distribution of measurement values ​​of multiple patterns becomes uniform based on a combination of at least two control parameters from among the control parameters of irradiation current density, pull-up electric field, acceleration voltage, magnification, scan method, and scan rotation.

[0011] According to the present invention, it is possible to provide a charged particle beam device that can avoid shading or distortion caused by differences in charge between patterns and improve throughput. Problems, configurations, and effects other than those described above will become clear from the description of the following embodiments.

[0012] FIG. 1 is a diagram showing a schematic configuration of a scanning electron microscope (SEM) according to a first embodiment of the present invention; FIG. 2 is a diagram showing a distribution of length measurement values ​​for each charge; FIG. 3 is a flowchart for determining imaging conditions from an experiment; FIG. 4 is a diagram showing an example of a database of control parameters and length measurement value distributions; FIG. 5 is a flowchart for determining imaging conditions from a database; FIG. 6 is a diagram showing an example of the relationship between irradiation current and charging potential; FIG. 7 is a diagram showing an example of the relationship between irradiation current and charging potential when a pull-up electric field is changed; FIG. 8 is a diagram showing an example of the relationship between a pull-up electric field and charging potential; FIG. 9 is a diagram showing an example of the relationship between a pull-up electric field and charging potential when the irradiation current is changed; FIG. 10 is a diagram showing an example of a database of control parameters and charging potential; FIG. 11 is a diagram showing an example of a GUI; FIG. 12 is a diagram showing an example in which three different patterns exist; FIG. 13 is a diagram showing the relationship between irradiation current and charging potential for each pattern before adjustment; FIG. 14 is a diagram showing the relationship between irradiation current and charging potential for each pattern after adjusting an acceleration voltage; FIG. 15 is a diagram showing the relationship between irradiation current and charging potential for each pattern after adjusting an acceleration voltage and a pull-up electric field; FIG. 16 is a diagram showing an example of the distribution of two-dimensional pattern shapes in a review SEM according to a second embodiment of the present invention; FIG. 17 is a diagram showing a schematic configuration of a multi-beam SEM according to a third embodiment of the present invention;

[0013] In this specification, examples of charged particle beam devices include SEMs and focused ion beam (FIB) devices, but in this specification, SEMs will be described as an example. Furthermore, in this specification, at least secondary electrons (SEs) and backscattered electrons (BSEs) generated from a sample are referred to as signal electrons generated from the sample. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0014] In this embodiment, an example will be described assuming a critical dimension SEM (CD-SEM). FIG. 1 is a diagram showing a schematic configuration of a scanning electron microscope (SEM) 100, which is a charged particle beam device according to this embodiment. As shown in FIG. 1, the scanning electron microscope 100 mainly comprises an electron gun 101, a condenser lens 103, a primary electron deflector (scanning deflector) 104, an objective lens 105, a signal electron deflector 107, a condenser lens (opening angle adjustment lens) 108, a detector 109, a signal electron aperture 110, a signal electron deflector 111, a detector 113, a calculation unit 114, and a memory unit 115. Although not shown, the scanning electron microscope 100 also has a display unit that accepts input from a user and displays various parameters and observation patterns. Here, the calculation unit 114 is realized by, for example, a processor such as a CPU (not shown), a ROM for storing various programs, a RAM for temporarily storing data in the calculation process, and a storage device such as an external storage device, and the processor such as the CPU reads and executes the various programs stored in the ROM, and stores the calculation results that are the execution results in the RAM, an external storage device, or cloud storage via a network connection, etc.

[0015] As shown in FIG. 1 , a scanning electron microscope 100 includes an electron gun 101, an electron beam (primary electron beam) 102, which is generated by the electron gun 101 and converged by a condenser lens 103, and then focused onto a sample 106 by an objective lens 105 for irradiation. The aperture angle of the electron beam (primary electron beam) 102 can be adjusted by a condenser lens (aperture angle adjustment lens) 108. A primary electron deflector (scanning deflector) 104 causes the electron beam (primary electron beam) 102 to scan an electron beam scanning area of ​​the sample 106. By two-dimensionally scanning and irradiating the electron beam (primary electron beam) 102, electrons are excited within the sample 106, and signal electrons emitted from the sample 106 are detected by detectors 109 and 113. A calculation unit 114 converts the detection signal into an image, thereby obtaining an observation image of the sample 106. Signal electrons emitted from the sample 106 are separated by a signal electron deflector 107 into electrons that pass through a signal electron aperture 110 and electrons that collide with the signal electron aperture 110. The electrons that collide with the signal electron aperture 110 generate tertiary electrons, which are detected by a detector 109. The electrons that pass through the signal electron aperture 110 are deflected by a signal electron deflector 111 toward a detector 113 and detected by the detector 113. As shown in FIG. 1 , some scanning electron microscopes are provided with an energy filter 112 that can discriminate signal electrons according to energy, in front of the detector 113, and the detector 113 detects the electrons that have passed through the energy filter 112. It is possible to estimate the charged state of the sample 106 from the change in the signal amount when the voltage applied to the energy filter 112 is changed. However, charge measurement using the energy filter 112 has the problem of taking time, and in the future, it will be difficult to measure charge using an energy filter 112 that can discriminate signal electrons according to energy. ２This is not realistic for achieving high-throughput measurements of 100 kJ / hr or more. The calculation unit 114 controls the optical elements of the scanning electron microscope 100, the voltage applied to the energy filter 112, the deflection amount of the signal electron deflector 107, and the composite ratio of the signals detected by the detectors 109 and 113. The calculation unit 114 also creates an observation image of the sample 106 using the detection signals of the signal electrons detected by the detectors 109 and 113. The memory unit 115 is a storage device that stores data used by the calculation unit 114. For example, a database (DB) of observation conditions and charging potential for each pattern, as shown in FIG. 10, can be stored. The calculation unit 114 determines imaging conditions such as the irradiation current density, pull-up field, acceleration voltage, scanning method, and scan rotation based on the database (DB) stored in the image memory. Note that the calculation unit 114 may be replaced with another calculation device to determine the imaging conditions. Furthermore, imaging conditions can also be determined experimentally without a database (DB).

[0016] First, we will explain a method for experimentally determining observation conditions without using a database (DB). Figure 2 shows the distribution of measurement values ​​for each charge. As shown in Figure 2, the distribution of measurement values ​​differs depending on the charge. Specifically, in the case of a positive charge (shown on the left side of Figure 2), the measurement values ​​at the center of the field of view are thicker than those outside the field of view, whereas in the case of a negative charge (shown on the right side of Figure 2), the measurement values ​​at the center of the field of view are thinner. This distribution is known to be caused by the difference in charge from the outside of the field of view. On the other hand, in the case of zero charge (shown in the center of Figure 2), no distribution of measurement values ​​occurs. By utilizing this characteristic, it is possible to control the charge of multiple patterns to zero by selecting observation conditions that flatten the distribution of measurement values ​​for all multiple patterns.

[0017] The method for determining imaging conditions will be described using the flowchart shown in FIG. 3. First, in step S300, the region to be imaged and the patterns contained within that region are selected. In this example, we consider a case in which two types of patterns, pattern A and pattern B, are mixed. Next, in step S301, the control parameters and control ranges are set. For example, the control parameters are set to the probe current and the pull-up field, and the control ranges for each parameter are set to 8 pA to 500 pA (probe current) and 2 kV / mm to 4 kV / mm (pull-up field). The conditions that minimize the variation in the measurement value distribution within the field of view are selected using the control parameters and control ranges specified in step S301, and the imaging conditions are determined (step S302). At this time, the appropriate way to change each parameter can be determined from the measurement value distribution. For example, in the case of a positive charge shown in the right diagram of FIG. 2, a flat distribution can be obtained by increasing the probe current or decreasing the pull-up field. Conversely, in the case of a negative charge shown in the right diagram of FIG. 2, a flat distribution can be obtained by decreasing the probe current or increasing the pull-up field. The reasons for this will be discussed later with reference to FIGS. 6 to 9.

[0018] Next, a method for determining imaging conditions based on a database (DB) will be described. A database (DB) of the distribution of length measurement values ​​versus control parameters, as shown in FIG. 4, is created in advance. Here, the control parameters are the irradiation current and the pull-up electric field on the axes, and the length measurement values ​​at the center of the field of view (FOV) / the length measurement values ​​at the edge of the field of view are plotted as a two-dimensional color map. However, the database (DB) used varies depending on the number of control parameters, i.e., three-dimensional when there are three control parameters, and four-dimensional when there are four control parameters. A method for determining imaging conditions will be described using the flowchart shown in FIG. 5. In creating the database (DB), it is not necessary to simultaneously capture multiple patterns within the field of view (FOV). Images can be captured for each pattern, or multiple patterns can be acquired collectively. In step S500, the region to be imaged and the patterns contained within the region are first selected. As in the case of FIG. 3 described above, consider a case in which two types of patterns, pattern A and pattern B, are mixed. Next, in step 501, the control parameters and the range to be controlled are set. 4, imaging conditions are presented that will make the distribution of measurement values ​​for multiple patterns uniform (step S502). At this time, there is no need to change the observation conditions or check the distribution of measurement values ​​as described above, and the cross points of the contour lines that make the measurement values ​​for each pattern uniform become the optimal conditions.

[0019] As shown in Figure 1, if an energy filter is installed in front of the detector, the energy filter 112 can be used to measure the surface potential of the sample 106 and select conditions that will result in zero charge for multiple patterns. Figure 6 shows an example of charge potential when the probe current is used as a control parameter. As the probe current is increased, the number of "return electrons," which are electrons that are once emitted and return to the sample, increases, reversing the positive charge to a negative charge. The rate of change varies depending on the sample. For example, when graphs of Pattern A and Pattern B are plotted together, a crosspoint always appears somewhere. As shown in Figure 6, if the crosspoint is positive, increasing the pull-up field can make the crosspoint overlap with zero charge, as shown in Figure 7. By selecting the appropriate pull-up field and probe current conditions, simultaneous zero charge for multiple patterns can be achieved, leading to reduced brightness unevenness and distortion. Figure 8 shows an example when the pull-up field is selected as a control parameter. It has been found that increasing the pull-up field reduces the aforementioned return electrons and monotonically increases positive charge. When the graphs of Pattern A and Pattern B are plotted together, a crosspoint always appears due to the difference in sensitivity to the pull-up field. For example, if the cross point is positively charged, the cross point can be made to overlap with the zero charge by increasing the irradiation current as shown in FIG.

[0020] FIG. 10 shows an example of a database of control parameters and charge potential. As shown in FIG. 10, a database (DB) can also be created using a color bar representing the charge potential. When the probe current and pull-up field are selected as control parameters, a zero-charge contour line is generated for each pattern. The crossing point between these contour lines represents the optimal condition. Since it takes time to acquire data for all points when creating a database (DB), it is possible to acquire data for only a few points and then calculate the remaining data from the acquired data. Because the sample potential changes linearly with respect to the pull-up field, the slope can be inferred by acquiring at least two points. It is also possible to estimate the potential using simulation. FIG. 11 shows an example of a GUI. As shown in FIG. 11, the display unit (not shown) of the scanning electron microscope (SEM) 100 allows the user to input the desired observation position in the position information input area 1101 and display the observed pattern in the image display area 1100. The user inputs the observation pattern in the pattern input area 1102, inputs the parameters to be controlled and their ranges in the control parameter input area 1103, and clicks the apply button 1104. The measurement value distribution or the charge potential is measured while changing the imaging conditions, and the point where the cross point coincides with zero charge is displayed in the optimum condition output area 1105. These operations are executed by the calculation unit 114. Furthermore, in the control parameter input area 1103, the user sets a range for the irradiation current "Ip [pA]", the magnification "Magnification", the pull-up voltage "Vb [kV]", and the acceleration voltage "Vacc [kV]", and when the apply button 1104 is clicked, the calculation unit 114 outputs the optimum values ​​of the irradiation current "Ip [pA]", the magnification "Magnification", the pull-up voltage "Vb [kV]", and the acceleration voltage "Vacc [kV]" to the optimum condition output area 1105.

[0021] As already explained, charge control for multiple patterns requires optimization of multiple parameters, such as the probe current and the pull-up electric field. When the pull-up voltage also serves as a deceleration voltage for the primary electrons, changing the pull-up electric field changes the conditions of the primary optical system, which raises concerns about the impact on magnification and Rot. In this case, feedback is provided to the primary electron deflector 104 to readjust the primary optical conditions.

[0022] FIG. 12 shows an example in which three different patterns exist. As shown in FIG. 12, the three different patterns include a fine line and space pattern A 1400, a coarse line and space pattern B 1401, and a no-pattern C 1402. FIG. 13 shows the relationship between the probe current and the charge potential for each pattern before adjustment. The probe current value at which the charge potential reverses from positive to negative is small in the order of pattern A < pattern B < pattern C. This is because the more patterns there are, the more likely it is that localized positive charge will be formed, and return electrons will be generated. As shown in FIG. 13, the crosspoints between pattern A and pattern B, pattern B and pattern C, and pattern C and pattern A are each realized with different current values. In this state, simultaneous zero charge for multiple patterns cannot be achieved no matter how much the probe current is adjusted. Therefore, it is necessary to optimize the pull-up field and acceleration voltage by adding control parameters to the probe current. It is important to note that, for example, changing the scan speed can control the charge, but this is equivalent to changing the probe current density and is not an independent parameter. Simultaneous charge control of three types of patterns requires optimizing three independent charge control parameters. Figure 14 shows the relationship between the probe current and the charge potential for each pattern after adjusting the acceleration voltage. Adjusting the acceleration voltage brings the cross points of the three patterns, i.e., pattern A, pattern B, and pattern C, closer together, but the zero charge and the cross points do not overlap. As shown in Figure 15, further adjusting the pull-up field can be used to adjust the cross points so that they overlap with the zero charge, thereby achieving simultaneous zero charge for the three patterns. Furthermore, if there are four types of patterns, four independent charge control parameters are required. An example of a charge control parameter independent of the acceleration voltage, probe current, and pull-up field is the observation magnification.

[0023] As described above, according to this embodiment, it is possible to provide a charged particle beam apparatus that can avoid shading or distortion caused by differences in charge among patterns and improve throughput.

[0024] In this example, an example will be described assuming an inspection SEM (review SEM). The device configuration of a review SEM is basically the same as that shown in Figure 1, but the inspection flow differs from that of a critical dimension SEM (CD-SEM). The location of the defect is roughly identified using an optical inspection device, and then a detailed inspection is performed using an electron microscope (SEM). Therefore, instead of simultaneously imaging multiple patterns, by presetting conditions so that the charge of multiple patterns contained in the wafer (sample 106) to be inspected is all zero, it is possible to reduce inspection omissions due to uneven brightness or distortion.

[0025] Review SEM performs data matching with design drawings and detects any discrepancies from the drawings as defects. Therefore, it is necessary to determine imaging conditions based on the two-dimensional pattern size distribution, rather than simple length measurement values. Figure 16 shows an example of two-dimensional pattern shape distribution. As shown in the right diagram of Figure 16, with zero charge, the pattern is made up of a series of equal-sized perfect circles. However, with positive charge, as shown in the left diagram of Figure 16, the outer circle has an elliptical shape. When determining imaging conditions experimentally, it is best to set the optical conditions so that the pattern shape is the same at all positions.

[0026] It is also possible to create a database of pattern shape distributions offline in advance, and use the created database to determine optical conditions.

[0027] According to this embodiment, the same effects as those of the first embodiment can be achieved.

[0028] In this embodiment, an example assuming a multi-beam SEM will be described. FIG. 17 is a diagram showing the schematic configuration of a multi-beam SEM 1300, a charged particle beam device according to this embodiment. Components similar to those shown in FIG. 1 are designated by the same reference numerals, and redundant explanations will be omitted below. As shown in FIG. 17 , many parts are the same as those in FIG. 1 . However, in the multi-beam SEM 1300, a beam splitter 1301 is provided midway along the primary electron trajectory to split the primary beam (electron beam 102). Furthermore, because the signal from each field of view must be imaged separately, the same number of multi-detectors 1302 as the number of fields of view (FOVs) are provided. Because the multi-beam SEM 1300 can simultaneously image a wide range, it is expected that multiple patterns will often coexist. A distinctive feature of the multi-beam SEM 1300 is that the secondary electron optical conditions also have a significant impact on image quality. The secondary electron optical conditions are controlled by the signal electron deflector 107, and adjustments must be made so that the signal from each field of view (FOV) correctly reaches each detector 1302. Therefore, the signal electron deflector 107 is more important than the length measurement SEM or review SEM.

[0029] According to this embodiment, the throughput can be further improved compared to the first embodiment.

[0030] In the above-described first embodiment, the case where the pulling electric field is changed has been described. However, since the change in the pulling electric field leads to a change in the energy of the secondary electrons, it becomes necessary to readjust the secondary optical system.

[0031] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment.

[0032] 100...Scanning electron microscope (SEM), 101...Electron source, 102...Electron beam, 103...Condenser lens, 104...Primary electron deflector, 105...Objective lens, 106...Sample, 107...Signal electron deflector, 108...Condenser lens (opening angle adjustment lens), 109...Detector, 110...Signal electron aperture, 111...Signal electron deflector, 112...Energy filter, 113...Detector, 114...Calculation unit, 115...Memory unit, 1100...Image display area, 1101...Position information input area, 1102...Pattern input area, 1103...Control parameter input area, 1104...Apply button, 1105...Optimal condition output area, 1300...Multi-beam SEM, 1301...Beam splitter, 1302...Multi-detector

Claims

1. A charged particle beam device comprising: a scanning deflector that scans a charged particle beam emitted from a charged particle source; a signal electron deflector that deflects the trajectory of signal electrons emitted from a sample; a detector that detects signal electrons obtained based on the scanning of the charged particle beam; and a pull-up electrode that pulls up the signal electrons to the detector, characterized in that when imaging an area including multiple patterns, the device has a calculation unit that determines imaging conditions such that the distribution of measurement values ​​of multiple patterns is uniform based on a combination of at least two of the control parameters: irradiation current density, pull-up electric field, acceleration voltage, magnification, scan method, and scan rotation.

2. A charged particle beam device as described in claim 1, characterized in that the calculation unit determines the imaging conditions by measuring a plurality of patterns of measurement value distribution and selecting imaging conditions that make the measurement value distribution constant within a surface.

3. A charged particle beam device as described in claim 1, comprising a database created in advance, and wherein the calculation unit determines the imaging conditions by referring to the database and selecting imaging conditions that result in a constant distribution of measurement values ​​for multiple patterns.

4. A charged particle beam device according to claim 3, wherein the database stores a distribution of measurement values ​​with respect to control parameters.

5. A charged particle beam device as described in claim 2, characterized in that the calculation unit determines the imaging conditions by selecting imaging conditions so that the charged potential of multiple patterns to be measured falls within a range of charges specified by a user.

6. A charged particle beam device according to claim 3, wherein the database holds the relationship between a control parameter and a charge potential, and the charge potential is plotted on a color bar.

7. A charged particle beam device as described in claim 6, characterized in that the calculation unit determines the imaging conditions by selecting imaging conditions based on the database so that the charged potential of multiple patterns to be measured falls within a range of charge specified by a user.

8. A charged particle beam device as described in claim 1, comprising a display unit, the display unit having on its screen a position information input area in which a position to be observed can be input, an image display area in which the pattern to be observed is displayed, and a control parameter input area in which parameters to be controlled and their ranges can be input, the calculation unit displaying the imaging conditions determined in an optimal condition output area.

9. A charged particle beam device as described in claim 2, comprising a display unit and a memory unit for storing the relationship between the measured measurement value distribution of multiple patterns and the control parameters, namely, irradiation current density, pull-up electric field, acceleration voltage, magnification, scan method, and scan rotation, and the calculation unit displays on the display unit the imaging conditions that make the difference between the measurement value distribution of multiple patterns zero.

10. A charged particle beam device according to claim 1, characterized in that the scanning deflector readjusts primary optical conditions in response to the determination of imaging conditions by the calculation unit.

11. A charged particle beam device as described in claim 1, characterized in that the signal electron deflector readjusts secondary optical conditions in response to the determination of imaging conditions by the calculation unit.

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