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

Technical Field

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

Background Art

[0002] With the miniaturization and high integration of semiconductor patterns, even a slight shape difference has come to affect the operating characteristics of devices, and the need for shape management has been increasing. Due to this, a scanning electron microscope (SEM: Scanning Electron Microscope) used for semiconductor inspection and measurement has been required to have higher sensitivity and higher accuracy than ever before. A scanning electron microscope is a device that detects electrons emitted from a sample, generates a signal waveform by detecting such electrons, and measures, for example, the dimensions between peaks (pattern edges).

[0003] In recent years, as a technology for forming fine patterns of 10 nm or less on a wafer, the introduction of EUV (Extreme UltraViolet) lithography has been promoted. In EUV lithography, it has been found that defects that occur randomly, called stochastic defects, are a problem. As a result, the need for inspection across the entire wafer has increased, and higher throughput is required for inspection devices.

[0004] To increase inspection efficiency (throughput), it is possible to inspect a wide area at once using low-magnification imaging with high current. Low-magnification observation necessitates imaging multiple patterns simultaneously, but it is known that the sample charge differs for each pattern. The effect of the charge is significant, particularly deflecting the trajectories of signal electrons generated from the sample. This results in various phenomena that reduce inspection accuracy, such as image distortion, shading (brightness unevenness), and contrast abnormalities. Furthermore, during low-magnification imaging, it is possible to capture images containing multiple patterns in a single field of view. Since different patterns have different sample charges, shading and distortion due to charge differences between patterns are a problem. Several charge control methods have been proposed to suppress the effect of sample charge on signal electron trajectories.

[0005] For example, Patent Document 1 describes a charged particle beam irradiation method for samples that contain multiple different materials within the pre-irradiation area or where the density of patterns within the pre-irradiation area varies depending on the location. This method involves dividing the pre-irradiation area into multiple regions and applying a charge using beams with different irradiation conditions to suppress non-uniformity of charging. However, this technique requires region division, raising concerns about reduced throughput. Furthermore, there is no description of a method for imaging without pre-irradiation.

[0006] Furthermore, Patent Document 2 describes a method for acquiring Field of View (FOV) images by setting spaced beam irradiation points. It also describes a method for controlling the deflector to scan the charged particle beam at a higher speed when irradiating the sample positions between irradiation points than when irradiating the sample positions corresponding to each irradiation point (the sample positions corresponding to each pixel for signal detection). This method can mitigate or control the effects of charging in minute regions within the FOV. Although Patent Document 2 describes charge differences in minute regions, it does not describe imaging involving multiple patterns. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2011-210509 [Patent Document 2] International Publication No. 2015-045498 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] In charged particle beam imaging, shading and distortion caused by charge differences between patterns are a problem when imaging with multiple patterns. As shown in Patent Document 1, a method of creating images with different imaging conditions by dividing the region has been proposed, but a method for imaging different patterns simultaneously under conditions that do not cause charge differences has not been disclosed. Also, as shown in Patent Document 2, a method of avoiding charging of minute regions by adjusting the irradiation point and scanning speed has been proposed, but this has not been disclosed for cases involving multiple patterns. For the above reasons, it is desirable to be able to capture images with multiple patterns without pre-irradiation or region division, and for this purpose, simultaneous control of the charging of multiple patterns is necessary.

[0009] Therefore, the present invention provides a charged particle beam apparatus that can avoid shading or distortion caused by charge differences between patterns and improve throughput. [Means for solving the problem]

[0010] To solve the above problems, the charged particle beam apparatus according to the present invention comprises a scanning deflector for scanning a charged particle beam emitted from a charged particle source, a signal electron deflector for deflecting the trajectory of signal electrons emitted from a sample, a detector for detecting signal electrons obtained based on scanning the charged particle beam, and a pull-up electrode for pulling the signal electrons to the detector. When imaging a region containing multiple patterns, the apparatus has a calculation unit that determines imaging conditions such that the distribution of measured values ​​of multiple patterns becomes uniform, based on a combination of at least two control parameters from among the control parameters: irradiation current density, pull-up field, acceleration voltage, magnification, scanning method, and scan rotation. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a charged particle beam apparatus that can avoid shading or distortion caused by charge differences between patterns and improve throughput. Other issues, configurations, and effects not mentioned above will be clarified by the following description of the embodiments. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows a schematic configuration of a scanning electron microscope (SEM) according to Example 1 of the present invention. [Figure 2] This figure shows the distribution of measured values ​​for each charge level. [Figure 3] This is a flowchart for determining imaging conditions from experiments. [Figure 4] This figure shows an example of a database of control parameters and measured value distributions. [Figure 5] This is a flowchart for determining imaging conditions from a database. [Figure 6] This figure shows an example of the relationship between irradiation current and charge potential. [Figure 7] This figure shows an example of the relationship between the irradiation current and the charging potential when the electric field for pulling up is changed. [Figure 8] This figure shows an example of the relationship between the electric field pulling up and the charging potential. [Figure 9] It is a diagram showing an example of the relationship between the pull-up electric field and the charging potential when the irradiation current is changed. [Figure 10] It is a diagram showing an example of a database of control parameters and charging potential. [Figure 11] It is a diagram showing an example of a GUI. [Figure 12] It is a diagram showing an example where there are three different patterns. [Figure 13] It is a diagram showing the relationship between the irradiation current and the charging potential of each pattern before adjustment. [Figure 14] It is a diagram showing the relationship between the irradiation current and the charging potential of each pattern after the acceleration voltage is adjusted. [Figure 15] It is a diagram showing the relationship between the irradiation current and the charging potential of each pattern after the acceleration voltage and the pull-up electric field are adjusted. [Figure 16] It is a diagram showing an example of the distribution of the two-dimensional pattern shape in the review SEM according to Example 2 of the present invention. [Figure 17] It is a diagram showing a schematic configuration of a multi-beam SEM according to Example 3 of the present invention.

Mode for Carrying Out the Invention

[0013] In this specification, as a charged particle beam device, for example, there are a SEM, a focused ion beam (FIB) device, etc. In this specification, the SEM will be described as an example. Also, in this specification, at least secondary electrons (SE) and backscattered electrons (BSE) generated from the sample, etc. are referred to as signal electrons generated from the sample. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment

[0014] In this embodiment, an embodiment assuming a length measurement SEM (CD-SEM) will be described. Figure 1 shows a schematic configuration of a scanning electron microscope (SEM) 100, which is a charged particle beam apparatus according to this embodiment. As shown in Figure 1, the scanning electron microscope 100 comprises, as its main components, 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 diaphragm 110, a signal electron deflector 111, a detector 113, a calculation unit 114, and a storage unit 115. Although not shown, the scanning electron microscope 100 also has a display unit for receiving user input and displaying various parameters and observation patterns. The calculation unit 114 is implemented using, for example, a processor such as a CPU (not shown), a ROM for storing various programs, a RAM for temporarily storing data during the calculation process, and a storage device such as an external storage device. The processor such as the CPU reads and executes the various programs stored in the ROM, and stores the calculation results, which are the execution results, in RAM, an external storage device, or cloud storage via a network connection.

[0015] As shown in Figure 1, the scanning electron microscope 100 focuses the electron beam (primary electron beam) 102 generated by the electron gun 101 using a condenser lens 103, and then focuses it onto the sample 106 using an objective lens 105 for irradiation. At this time, the aperture angle of the electron beam (primary electron beam) 102 can be adjusted using a condenser lens (aperture angle adjustment lens) 108. The primary electron deflector (scanning deflector) 104 scans the electron beam (primary electron beam) 102 over the electron beam scanning area of ​​the sample 106. By scanning and irradiating with the electron beam (primary electron beam) 102 in two dimensions, signal electrons are excited within the sample 106 and emitted from the sample 106. These signal electrons are detected by detectors 109 and 113, and the calculation unit 114 converts the detected signals into an image to obtain an observation image of the sample 106. Signal electrons emitted from sample 106 are separated through the signal electron deflector 107 into electrons that pass through the signal electron aperture 110 and electrons that collide with the signal electron aperture 110. Electrons that collide with the signal electron aperture 110 generate tertiary electrons, which are detected by the detector 109. Electrons that pass through the signal electron aperture 110 are deflected towards the detector 113 through the signal electron deflector 111 and detected by the detector 113. As shown in Figure 1, some scanning electron microscopes are equipped with an energy filter 112 in front of the detector 113 that can discriminate signal electrons by energy, and the detector 113 detects electrons that pass through the energy filter 112. It is possible to estimate the charge state of sample 106 from the change in the amount of signal when the voltage applied to the energy filter 112 is changed. However, there is a problem that charge measurement with the energy filter 112 is time-consuming, and in the future, it will be 1 cm 2Aiming for high-throughput measurements of more than / hr is not realistic. The calculation unit 114 controls each optical element of the scanning electron microscope 100, controls the voltage applied to the energy filter 112, controls the deflection amount of the signal electron deflector 107, and calculates the composite ratio of signals detected by detectors 109 and 113. The calculation unit 114 also creates an observation image of the sample 106 using the detection signals of signal electrons detected by detectors 109 and 113. The memory unit 115 is a memory device that stores data used by the calculation unit 114. For example, it can store a database (DB) of observation conditions and charge potentials for each pattern, as shown in Figure 10. Based on the database (DB) stored in the image memory, the calculation unit 114 determines imaging conditions such as irradiation current density, pull-up field, acceleration voltage, scanning method, and scan rotation. Alternatively, another calculation device may be provided instead of the calculation unit 114 to determine the imaging conditions. It is also possible to determine the imaging conditions experimentally even 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 measured values ​​for each charge level. As shown in Figure 2, the distribution of measured values ​​differs depending on the charge level. Specifically, in the case of positive charge shown in the left figure of Figure 2, the measured values ​​at the center of the field of view are thicker than those at the outside of the field of view, while in the case of negative charge shown in the right figure of Figure 2, the values ​​at the center of the field of view are thinner. It is known that this distribution occurs due to the charge difference between the outside and outside of the field of view. On the other hand, in the case of zero charge shown in the center figure of Figure 2, no distribution of measured values ​​is observed. By utilizing this characteristic and selecting observation conditions such that all measurement value distributions for multiple patterns become flat, it is possible to control multiple charge levels to zero.

[0017] The method for determining imaging conditions will be explained using the flowchart shown in Figure 3. First, in step S300, the region to be imaged and the patterns contained within that region are selected. In this case, we consider the case where two types of patterns, pattern A and pattern B, are mixed. Next, in step S301, the control parameters and the control range are set. For example, the control parameters are set to irradiation current and pull-up electric field, and the control ranges for each parameter are set to 8pA to 500pA (irradiation current) and 2kV / mm to 4kV / mm (pull-up electric field). In step S301, the conditions that result in the smallest variation in the distribution of measured values ​​within the field of view are selected, and the imaging conditions are determined (step S302). At this time, it is possible to determine how to appropriately change each parameter from the distribution of measured values. For example, in the case of positive charge shown in the right figure of Figure 2, a flat distribution can be obtained by increasing the irradiation current or decreasing the pull-up electric field. Conversely, in the case of negative charge shown in the right figure of Figure 2, a flat distribution can be obtained by decreasing the irradiation current or increasing the pull-up electric field. The reason for this will be explained later using Figures 6 to 9.

[0018] Next, we will explain how to determine imaging conditions based on a database (DB). A database (DB) of the distribution of measured values ​​for control parameters is created in advance, as shown in Figure 4. Here, the irradiation current and the pulling-up electric field are taken as the control parameters, and the measured values ​​at the center of the field of view (FOV) / measured values ​​at the edge of the field of view are plotted as a two-dimensional color map. However, the database (DB) used will differ depending on the number of control parameters; for example, a three-dimensional database (DB) for three control parameters and a four-dimensional database (DB) for four control parameters. We will explain how to determine imaging conditions using the flowchart shown in Figure 5. When creating the database (DB), it is not necessary to include multiple patterns in the field of view (FOV) at the same time; each pattern can be imaged separately, or multiple patterns can be acquired together. In step S500, first select the area to be imaged and the patterns to be included within that area. As in the case of Figure 3 above, consider the case where two types of patterns, pattern A and pattern B, are mixed. Next, in step 501, set the control parameters and the range to be controlled. Referring to the database (DB) shown in Figure 4, imaging conditions are presented that result in a uniform distribution of measured values ​​for multiple patterns (step S502). At this point, it is not necessary to change the observation conditions and check the distribution of measured values ​​as described above, and the crossing point of the contour lines that result in a uniform distribution of measured values ​​for each pattern becomes the optimal condition.

[0019] As shown in Figure 1, if an energy filter is mounted in front of the detector, the surface potential of the sample 106 can be measured using the energy filter 112, and conditions can be selected such that multiple charge patterns become zero. Figure 6 shows an example of charge potential when the irradiation current is used as a control parameter. As the irradiation current is increased, the number of "return electrons" that are emitted and return to the sample increases, causing a reversal from positive charge to negative charge. The rate of change at this time differs depending on the sample, so if the graphs of pattern A and pattern B are plotted together, for example, a crossover point will always be created somewhere. As shown in Figure 6, if the crossover point is positively charged, the crossover point can be made to be zero-charged by increasing the pull-up field, as shown in Figure 7. By selecting the conditions for the pull-up field and irradiation current at this time, simultaneous zero charging of multiple patterns can be achieved, leading to the suppression of brightness unevenness and distortion. Figure 8 shows an example when the pull-up field is selected as a control parameter. It is known that increasing the pull-up field reduces the return electrons mentioned above, and the positive charge increases monotonically. If the graphs of pattern A and pattern B are plotted together, a crossover point will always be created due to the difference in sensitivity to the pull-up field. For example, if the crossover point is positively charged, increasing the irradiation current, as shown in Figure 9, will cause the crossover point to become zero-charged.

[0020] Figure 10 shows an example of a database of control parameters and charge potential. As shown in Figure 10, a database (DB) can also be created by taking the charge potential as a color bar. When irradiation current and pull-up field are selected as control parameters, contour lines of zero charge are created for each pattern. The crossing points of these contour lines represent the optimal conditions. When creating a database (DB), acquiring data for all points takes time, so it is also possible to acquire data for only a few points and calculate the remaining data from the acquired data. Since the sample potential changes linearly with respect to the pull-up field, it can be estimated from the slope if at least two points are taken. It is also possible to estimate using simulation. Figure 11 shows an example of a GUI. The display unit (not shown) of the scanning electron microscope (SEM) 100, as shown in Figure 11, allows the user to input the desired observation location in the position information input area 1101 on the display screen and display the observation 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 charge potential is measured while changing the imaging conditions, and the point where the cross point coincides with zero charge is displayed in the optimal condition output area 1105. These operations are performed 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]". When the user clicks the apply button 1104, the calculation unit 114 outputs the optimal values ​​for the irradiation current "Ip [pA]", the magnification "Magnification", the pull-up voltage "Vb [kV]", and the acceleration voltage "Vacc [kV]" in the optimal condition output area 1105.

[0021] As already explained, controlling the charge in multiple patterns requires the optimization of several parameters, such as the irradiation current and the pulling-up field. If the pulling-up voltage also acts as a deceleration voltage for the primary electrons, changing the pulling-up field will change the conditions of the primary optical system, raising concerns about its impact on magnification and Rot. In this case, feedback is provided to the primary electron deflector 104 to readjust the primary optical conditions.

[0022] Figure 12 shows an example where there are three different patterns. As shown in Figure 12, consider a case where the three different patterns include regions with a fine Line & Space pattern A1400, a coarse Line & Space pattern B1401, and no pattern C1402. Figure 13 shows the relationship between the irradiation current and the charging potential for each pattern before adjustment. The irradiation current value at which the charging potential reverses from positive to negative is smallest for pattern A < pattern B < pattern C. The reason is that the more patterns there are, the easier it is for localized positive charging to form and for return electrons to be generated. As shown in Figure 13, the crossover points of pattern A and pattern B, pattern B and pattern C, and pattern C and pattern A are realized with different current values, and in this state, no matter how much the irradiation current is adjusted, simultaneous zero charging of multiple patterns cannot be achieved. Therefore, it is necessary to optimize the pull-up field and acceleration voltage in addition to the irradiation current as control parameters. It is important to note here that although charging can be controlled by changing the scan speed, for example, this is equivalent to changing the irradiation current density and is not an independent parameter. Simultaneous charging control of three different patterns requires the optimization of three independent charging control parameters. Figure 14 shows the relationship between irradiation current and charging potential for each pattern after adjusting the acceleration voltage. By adjusting the acceleration voltage, the crossover points of the three patterns, namely patterns A, B, and C, have moved closer together, but the zero charging point does not overlap with the crossover point. As shown in Figure 15, by further adjusting the pull-up field, it is possible to adjust the crossover point to overlap with the zero charging point, thereby achieving simultaneous zero charging for all three patterns. Furthermore, if there are four types of patterns, four independent charging control parameters will be required. An example of an independent charging control parameter, in addition to the acceleration voltage, irradiation current, and pull-up field, is the observation magnification.

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

[0024] This embodiment describes an example assuming a SEM for inspection (review SEM). The configuration of the review SEM is basically the same as that shown in Figure 1, but the inspection flow differs from that of the length-measuring SEM (CD-SEM). The flow involves roughly identifying the location of defects with an optical inspection device and then inspecting them in detail with an electron microscope (SEM). Therefore, instead of simultaneously imaging multiple patterns, the conditions are pre-set so that the charge of all multiple patterns contained in the wafer to be inspected (sample 106) becomes zero, and inspection is performed in this way, making it possible to reduce inspection errors due to brightness unevenness and distortion.

[0025] In review SEM, data matching is performed against design drawings, and any discrepancies are detected as defects. Therefore, it is necessary to determine imaging conditions from the distribution of two-dimensional pattern sizes, rather than from simple length measurements. Figure 16 shows an example of the distribution of two-dimensional pattern shapes. As shown in the right panel of Figure 16, in the case of zero charge, the pattern consists of rows of perfect circles of equal size, but in the case of positive charge, as shown in the left panel of Figure 16, the shape of the outer circles becomes elliptical. When experimentally determining imaging conditions, 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 beforehand and use that database to determine the optical conditions.

[0027] According to this embodiment, the same effects as those of Embodiment 1 described above can be achieved. [Examples]

[0028] In this example, we will describe an embodiment that assumes a multi-beam SEM. Figure 17 shows a schematic configuration of the multi-beam SEM1300, which is a charged particle beam apparatus according to this embodiment. Components similar to those shown in Figure 1 are denoted by the same reference numerals, and redundant explanations are omitted below. As shown in Figure 17, there are many parts that are the same as in Figure 1, but in the multi-beam SEM 1300, a beam splitter 1301 is installed in the middle of the primary electron trajectory to split the primary beam (electron beam 102). Also, since it is necessary to image the signals from each field of view separately, there are as many multi-detectors 1302 as there are fields of view (FOV). Because the multi-beam SEM 1300 can image a wide area at once, it is thought that there are many cases in which multiple patterns are mixed together. A key feature of the multibeam SEM1300 is that secondary electron optics conditions significantly impact image quality. These conditions are controlled by the signal-electron deflector 107, which needs to be adjusted to ensure that signals from each field of view (FOV) are correctly received by each detector 1302. Therefore, the signal-electron deflector 107 is more important in multibeam SEMs than in length-measuring or review SEMs.

[0029] According to this embodiment, throughput can be further improved compared to Embodiment 1.

[0030] In the above-described Example 1, we explained the case in which the pulling-up field is changed. However, since a change in the pulling-up field leads to a change in the energy of secondary electrons, readjustment of the secondary optical system becomes necessary.

[0031] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts 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. [Explanation of symbols]

[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 (angle adjustment lens), 109…Detector, 110…Signal electron diaphragm, 111…Signal electron deflector, 112…Energy filter, 113…Detector, 114…Calculation unit, 115…Storage 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…Multibeam SEM, 1301…Beam splitter, 1302…Multi-detector

Claims

1. A scanning deflector that scans the 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 for detecting signal electrons obtained based on scanning of the charged particle beam, The system includes a pull-up electrode for pulling the signal electrons into a detector, A charged particle beam apparatus characterized by having a calculation unit that determines imaging conditions such that the distribution of measured values ​​of multiple patterns becomes uniform, based on a combination of at least two control parameters, which are control parameters: irradiation current density, pulling electric field, acceleration voltage, magnification, scanning method, and scan rotation, when imaging a region containing multiple patterns.

2. A charged particle beam apparatus according to claim 1, The aforementioned arithmetic unit, A charged particle beam apparatus characterized by determining imaging conditions by measuring multiple patterns of length value distributions and selecting imaging conditions such that the length value distribution becomes constant within the plane.

3. A charged particle beam apparatus according to claim 1, Equipped with a pre-created database, The charged particle beam apparatus is characterized in that the calculation unit determines the imaging conditions by referring to the database and selecting imaging conditions such that multiple patterns of measured length value distributions become constant.

4. A charged particle beam apparatus according to claim 3, The charged particle beam apparatus is characterized in that the database stores the distribution of measured values ​​for control parameters.

5. A charged particle beam apparatus according to claim 2, The aforementioned arithmetic unit, A charged particle beam apparatus characterized by determining the imaging conditions by selecting imaging conditions such that the measured multiple patterns of charge potential fall within a charge range specified by the user.

6. A charged particle beam apparatus according to claim 3, The charged particle beam apparatus is characterized in that the database maintains the relationship between control parameters and charging potential, and the charging potential is represented by a color bar.

7. A charged particle beam apparatus according to claim 6, The aforementioned arithmetic unit, A charged particle beam apparatus characterized by determining imaging conditions by selecting imaging conditions based on the database such that the multiple patterns of charge potential measured fall within a charge range specified by the user.

8. A charged particle beam apparatus according to claim 1, It is equipped with a display unit, and on the screen of the display unit, A location information input area where you can input the location you want to observe, An image display area that displays the pattern to be observed, It has a control parameter input area in which the parameter to be controlled and its range can be input, The charged particle beam apparatus is characterized in that the calculation unit displays the determined imaging conditions in the optimal condition output region.

9. A charged particle beam apparatus according to claim 2, Equipped with a display unit, It has a memory unit that stores the relationship between the measured distribution of multiple patterns of measured length values ​​and the control parameters, namely the irradiation current density, pulling electric field, acceleration voltage, magnification, scanning method, and scan rotation. The charged particle beam apparatus is characterized in that the calculation unit displays the imaging conditions on the display unit such that the difference between multiple patterns of measured length value distributions becomes zero.

10. A charged particle beam apparatus according to claim 1, The scanning deflector is, A charged particle beam apparatus characterized by readjusting the primary optical conditions in accordance with the determination of imaging conditions by the calculation unit.

11. A charged particle beam apparatus according to claim 1, The charged particle beam apparatus is characterized in that the signal electron deflector readjusts the secondary optical conditions in accordance with the determination of imaging conditions by the calculation unit.

Images