Charged particle beam system and method of operating the same, method of recording a plurality of images

Abstract

The invention relates to a charged particle beam system comprising a deflection sub-system configured to deflect a charged particle beam in a deflection direction based on a sum of analog signals resulting from independent digital-to-analog conversion of a first digital signal and a second digital signal. The invention further relates to a method of configuring a charged particle beam system such that each of a plurality of regions of interest can be scanned by changing only the first digital signal while the second digital signal remains constant at a value associated with the respective region of interest. The invention further relates to a method of recording a plurality of images of a region of interest under the premise of reducing disturbances due to charge accumulation.

Description

Technical Field

[0001] This invention relates to a charged particle beam system and a method for operating the charged particle beam system. Specifically, the invention relates to a deflection system for deflecting a charged particle beam, a method for configuring the deflection system and using the charged particle beam system to record multiple images of a remote region of interest; and a computer program for configuring a controller of the charged particle beam system to execute the method.

[0002] Furthermore, the present invention relates to a method for recording multiple images of different regions of interest; and a computer program for configuring a controller of a charged particle beam system to execute the method. Background Technology

[0003] A typical charged particle beam system includes: a charged particle beam source configured to generate a charged particle beam; an objective lens configured to focus the charged particle beam onto a focal plane; and a deflection system configured to deflect the charged particle beam. A typical deflection system includes a counter, a DAC (digital-to-analog converter), an analog amplifier, and a field generator. The counter generates a digital output value that increases at a controlled rate. The DAC converts the digital output value from the counter into an analog signal. The analog amplifier amplifies the analog signal output from the DAC and applies the amplified analog signal to the field generator. The field generator uses the amplified analog signal to generate a magnetic and / or electric field for deflecting the charged particle beam.

[0004] The primary application of charged particle beam systems is wafer inspection. Wafers have a relatively large field of view compared to charged particle beam systems limited by deflection systems. To image remote regions of interest on a wafer, the field of view of the charged particle beam system must be large and / or the stage holding the wafer must be moved. Under the assumption of a constant bit depth for the DAC (Digital Deflector), a large field of view can be configured by selecting a large magnification, according to conventional deflection systems, at the cost of reducing the spatial sampling frequency of the resulting image, since the field of view and the maximum spatial sampling frequency are inversely related at a constant bit depth for the DAC. Moving the stage typically slows down the image acquisition rate and introduces errors due to stage drift. Therefore, conventional charged particle beam systems lack the ability to image remote regions of interest with high spatial sampling frequencies and high accuracy.

[0005] Another common problem in image recording using charged particle beam systems is charge buildup in the sample due to the impact of charged particles from the beam. This problem can be severe for samples with low conductivity. Charge buildup can generate unpredictable electric fields that affect the impacting charged particle beam, causing beam deflection and beam drift, and often resulting in worse images. Summary of the Invention

[0006] One feature of the present invention is to provide a charged particle beam system and a method for operating the charged particle beam system for imaging a remote region of interest with high spatial sampling frequency and high precision.

[0007] This feature is achieved by the subject matter of the independent claim. Preferred embodiments are defined in the dependent claims.

[0008] According to a first aspect of the invention, a charged particle beam system includes: a charged particle beam source configured to generate a charged particle beam; an objective lens configured to focus the charged particle beam onto a focal plane; a deflection system configured to deflect the charged particle beam; and a controller. The deflection system includes at least one deflector system. Each deflector system is configured to deflect the charged particle beam along a deflection direction. Multiple deflector systems are configured to deflect the charged particle beam along different deflection directions. Each deflection direction is generally substantially perpendicular to the optical axis of the charged particle beam system.

[0009] Each deflector system includes: a first DAC circuit configured to convert a first digital deflection signal into a first analog output signal within a first operating range by a step of a first step height; a second DAC circuit configured to convert a second digital deflection signal into a second analog output signal within a second operating range by a step of a second step height; an adder configured to receive the first analog output signal and the second analog output signal, and to output an analog deflection signal based on the sum of the received first analog output signal and the received second analog output signal; and a field generator configured to receive the analog deflection signal and generate a magnetic field and / or an electric field for deflecting a beam of charged particles using the received analog deflection signal.

[0010] The controller is configured to generate a first digital deflection signal and a second digital deflection signal for each deflector system.

[0011] The sample can be located in the focal plane of the objective lens for observation, analysis, or manipulation.

[0012] According to a second aspect of the invention, a method of operating a charged particle beam system includes: obtaining coordinates of a plurality of regions of interest on a sample; configuring a first DAC circuit such that a first scan range provided by the first DAC circuit is at least as large as the largest region of interest, the first scan range representing the length of a region in the focal plane of an objective lens that can be scanned by changing the first digital deflection signal while maintaining the second digital deflection signal; configuring a second DAC circuit such that a second scan range provided by the second DAC circuit is at least as large as the maximum distance between the regions of interest, the second scan range representing the length of a region in the focal plane that can be scanned by changing the second digital deflection signal while maintaining the first digital deflection signal; and recording an image of the regions of interest using the configured method.

[0013] The two DAC circuits in each deflector system can be configured and set independently, for example, such that the first DAC circuit provides a high-precision, small contribution to the analog deflection signal, while the second DAC circuit provides a medium-precision, large contribution to the analog deflection signal. This configuration allows for precise scanning at a high spatial sampling frequency (i.e., the neighboring residence positions of the charged particle beams on the sample are close to each other) within the scanning range provided by the first DAC circuit, and allows for a large field of view within the scanning range provided by the second DAC circuit.

[0014] A third aspect of the invention relates to a method for recording multiple images representing different regions of interest (ROIs) on a sample. The method includes recording multiple images representing multiple different ROIs on the sample. Recording the multiple images includes scanning a charged particle beam across multiple scanning regions, wherein each of the ROIs comprises multiple scanning regions, wherein every two scanning regions to be scanned consecutively are spaced at least a first minimum distance, the first minimum distance being at least 100 nm, and wherein every two scanning regions to be scanned consecutively belong to different ROIs within the ROIs.

[0015] According to this method, each segment of an image is recorded by sequentially recording multiple segments of the corresponding image. Each segment corresponds to a scanning area. Between continuously recording two segments by scanning a charged particle beam over the scanning area corresponding to two segments of the same image, a segment of another image is recorded by scanning a charged particle beam over the scanning area corresponding to a segment of another image. That is, two different segments of the same image are recorded alternately by recording segments of another image.

[0016] To reduce the impact of charge accumulation caused by scanning a charged particle beam on the sample, every two consecutive scanning regions are spaced at least a first minimum distance, which is at least 100 nm. Therefore, the charge accumulated in the first scanning region due to scanning the charged particle beam has almost no effect on the scanning of the second scanning region that will be scanned subsequently, because the second scanning region is far from the first scanning region. During the scanning of the second scanning region, the charge accumulated in the first scanning region may be distributed throughout the sample or dissipate. Therefore, the third scanning region that will be scanned subsequently can be located near the first scanning region, and the scanning of the first scanning region has little impact on the scanning of the third scanning region, because the charge accumulated in the first scanning region is dispersed or dissipated at this time.

[0017] Therefore, this method allows the recording of multiple images using a charged particle beam, which reduces interference from charge accumulation caused by guiding the charged particle beam to the sample.

[0018] A fourth aspect of the invention relates to a computer program comprising instructions that, when executed by a controller of a charged particle beam system, enable the charged particle beam system to perform any of the methods described herein. The charged particle beam system described herein can be used to perform the methods described herein. Attached Figure Description

[0019] In the following description, embodiments of the invention are illustrated with reference to the accompanying drawings.

[0020] Figure 1 A charged particle beam system according to an embodiment of the first aspect of the present invention is illustrated schematically.

[0021] Figure 2 The deflection system of a charged particle beam system is shown schematically.

[0022] Figure 3 The digital-to-analog conversion of the DAC circuit in the eccentric rotor system is illustrated schematically.

[0023] Figure 4 The scan range provided by the DAC circuitry of the bias rotor system is illustrated schematically.

[0024] Figure 5 This is a flowchart illustrating an embodiment of the second aspect of the present invention.

[0025] Figure 6 The scanning area on a sample according to an embodiment of the third aspect of the present invention and the scanning sequence for scanning the scanning area are shown.

[0026] Figure 7 Details about the scanned area on the sample are shown.

[0027] Figure 8 Details about the region of interest on the sample are shown.

[0028] Figure 9 This is a flowchart illustrating another embodiment of the third aspect of the present invention. Detailed Implementation

[0029] refer to Figure 1 This describes a charged particle beam system 1 according to a first aspect of the present invention. The charged particle beam system 1 includes a charged particle beam column 10, a controller 20, and a user interface 30. The user interface 30 is used to configure the controller 20. The controller 20 is configured to control the charged particle beam column 10. For example, the charged particle beam system 1 may be an electron beam microscope.

[0030] The charged particle beam column 10 includes a charged particle beam source 11, an objective lens 12, and a deflection system 13. Depending on the type of charged particle beam system, the charged particle beam column 10 may include additional components such as a condenser, an astigmatism reducer, a detector, etc. However, for simplicity, these additional components are neither shown nor described in more detail.

[0031] Charged particle beam source 11 is configured to generate charged particle beam 2. For example, charged particle beam 2 can be an electron beam or an ion beam. Charged particle beam source 11 is controlled by controller 20, as indicated by connection line 14.

[0032] Objective lens 12 is configured to focus the charged particle beam 2 onto focal plane 6. In this example, sample 3 is positioned within focal plane 6. Objective lens 12 may be a magnetic lens including a coil configured to generate a magnetic field for focusing the charged particle beam 2. Objective lens 12 may also be an electric lens including electrodes configured to generate an electric field for focusing the charged particle beam 2. Objective lens 12 is controlled by controller 20, as indicated by connection line 15.

[0033] Deflection system 13 is configured to deflect the charged particle beam 2 in at least one deflection direction. Deflecting the charged particle beam 2 means changing the propagation direction of the charged particle beam 2. (Refer to...) Figure 2 The deflection system 13 is described in more detail.

[0034] The charged particle beam system 1 also includes a stage 4, which is configured to position and orient the sample 3. The stage 4 is controlled by a controller 20, as indicated by the connection line 16.

[0035] The charged particle beam system 1 also includes a vacuum chamber 5, a vacuum chamber receiving stage 4, and a stage 4 for holding the sample 3 when it is held by the stage 4. A charged particle beam column 10 is connected to the vacuum chamber 5 such that a charged particle beam 2 is incident on the sample 3 held on the stage 4.

[0036] The controller 20 is configured to control the charged particle beam column 10 (particularly its components) and the stage 4. The controller 20 is connected to the user interface 30 via a connection cable 17.

[0037] User interface 30 can be used to define and manipulate parameters controlled by controller 20. For example, user interface 30 may include an input device 31 (such as a mouse or keyboard) for receiving user input, a processing unit 32 for processing the received input, and an output device 33 (such as a display) for outputting information to the user. Processing unit 32 is connected to controller 20 via connection cable 17. Processing unit 32 can transmit data to controller 20 for configuring controller 20, and can receive data (such as measurement data, configuration data, etc.) from controller 20.

[0038] The deflection system 13 is configured to deflect the charged particle beam 2, allowing it to be guided to multiple different positions within the focal plane 6, thereby directing the charged particle beam 2 to multiple different positions on the surface of the sample 3. This process of guiding the charged particle beam 2 to multiple different positions within the focal plane 6 by deflecting it can also be referred to as scanning.

[0039] refer to Figure 2 The deflection system 13 is described in more detail below. The deflection system 13 includes at least one deflector rotor system. Figure 2 In the example shown, deflection system 13 includes two deflector systems 40 and 50. Deflector system 40 is configured to deflect the charged particle beam 2 along a first deflection direction; deflector system 50 is configured to deflect the charged particle beam 2 along a second deflection direction. The first and second deflection directions are different directions that are substantially perpendicular to the optical axis of charged particle beam system 1 (e.g., the optical axis of objective lens 12). Deflector systems 40 and 50 have the same basic configuration but can be set and controlled independently.

[0040] The deflector system 40 includes a first DAC circuit 41 configured to convert a first digital deflection signal 40D1 into a first analog output signal 40A1 within a first operating range OR1 by a first step height SH1. The first operating range OR1 represents the range of first analog output signals 40A1 that can be generated (i.e., generated) by the first DAC circuit 41 using preset settings. The first step height SH1 represents the minimum difference between the first analog output signals 40A1 that can be generated (i.e., generated) by the first DAC circuit 41 using preset settings. (Reference) Figure 3 The details of the digital-to-analog conversion of the first DAC circuit 41 are described.

[0041] The deflector system 40 also includes a second DAC circuit 42, configured to convert the second digital deflection signal 40D2 into a second analog output signal 40A2 within a second operating range OR2 by a step of a second step height SH2. The second operating range OR2 represents the range of the second analog output signals 40A2 that can be generated by the second DAC circuit 42 using preset settings. The second step height SH2 represents the minimum difference between the second analog output signals 40A2 that can be generated by the second DAC circuit 42 using preset settings. (Reference) Figure 3 Describe the details of the digital-to-analog conversion of the second DAC circuit 42.

[0042] The first operating range OR1 and the second operating range OR2 are generally different from each other. The first step height SH1 and the second step height SH2 are generally different from each other.

[0043] The deflector system 40 also includes an adder 43 configured to receive a first analog output signal 40A1 and a second analog output signal 40A2, and to output an analog deflection signal 40A based on the sum of the received first analog output signal 40A1 and the received second analog output signal 40A2. For example, the adder may be a summing amplifier. The adder may also be referred to as a phase adder. For example, the adder 43 calculates the sum of the received first analog output signal 40A1 and the received second analog output signal 40A2, and outputs the calculated sum as the analog deflection signal 40A. Alternatively, the calculated sum may be amplified by another amplifier, and the amplified calculated sum may be output as the analog deflection signal 40A.

[0044] The deflector system 40 also includes a field generator 44 configured to receive an analog deflection signal 40A and use the received analog deflection signal 40A to generate a magnetic field and / or an electric field to deflect the charged particle beam 2. The field generator 44 may include coils configured to generate a magnetic field suitable for deflecting the charged particle beam 2. The field generator 44 may include electrodes configured to generate an electric field suitable for deflecting the charged particle beam 2. The received analog deflection signal 40A is used to excite the field generator 44.

[0045] The controller 20 determines the first digital deflection signal 40D1 and the second digital deflection signal 40D2, and inputs the first digital deflection signal 40D1 into the first DAC circuit 41 and the second digital deflection signal 40D2 into the second DAC circuit 42.

[0046] In particular, such as Figure 2As shown, the first DAC circuit 41 may include a first DAC 45 and a first amplifier 46. The first DAC 45 is configured to convert a first digital deflection signal 40D1 into a first analog intermediate signal 40I1, and the first amplifier 46 is configured to amplify the first analog intermediate signal 40I1 using a first amplification rate to generate a first analog output signal 40A1. Similarly, the second DAC circuit 42 may include a second DAC 47 and a second amplifier 48. The second DAC 47 is configured to convert a second digital deflection signal 40D2 into a second analog intermediate signal 40I2, and the second amplifier 48 is configured to amplify the second analog intermediate signal 40I2 using a second amplification rate to generate a second analog output signal 40A2. Predefined settings for the first DAC circuit 41 may be defined by the bit depth and the first amplification rate of the first DAC 45. Predefined settings for the second DAC circuit 42 may be defined by the bit depth and the second amplification rate of the second DAC 47. Generally, the bit depth and amplification rate can be different from each other. (Reference) Figure 3 More details describe the functions of the first DAC circuit 41 and the second DAC circuit 42.

[0047] Figure 3 A diagram illustrating the digital-to-analog conversion behavior of the first DAC circuit 41 and the second DAC circuit 42 is shown. The horizontal axis of the diagram represents the digital input values ​​(i.e., the potential value of the first digital deflection signal 40D1) input to the first DAC circuit 41 and the digital input values ​​(i.e., the potential value of the second digital deflection signal 40D2) input to the second DAC circuit 42. In this example, it is assumed that the first DAC circuit 41 (first DAC 45) has a bit depth of n and the second DAC circuit 42 (second DAC 47) has a bit depth of m, where m and n are integers and n is greater than m. However, alternatively, the bit depths m and n can also be the same or m can be greater than n. The bit depth of a DAC circuit (DAC) defines the number of bits of the digital input value that is converted into an analog output signal by the DAC circuit (DAC). In this case, the first DAC circuit 41 (first DAC 45) and the second DAC circuit 42 (second DAC 47) have different bit depths. However, this is merely an example, and the first DAC circuit 41 (first DAC 45) and the second DAC circuit 42 (second DAC 47) may have the same bit depth. To save costs, the second DAC circuit 42 (second DAC 47) may have a lower bit depth than the first DAC circuit 41 (first DAC 45). For example, the first DAC circuit 41 (first DAC 45) may have a bit depth of 12; and the second DAC circuit 42 (second DAC 47) may have a bit depth of 8.

[0048] The vertical axis of the graph represents the analog output signal generated based on the digital input value. Specifically, the first analog output signal 40A1 generated by the first DAC circuit 41 is represented by dots; and the second analog output signal 40A2 generated by the second DAC circuit 42 is represented by diamond dots. Although in Figure 3 Although not clearly shown, both the first DAC circuit 41 and the second DAC circuit 42 convert zero input to zero output.

[0049] The first step height SH1 represents the minimum difference between the first analog output signals 40A1 generated by the first DAC circuit 41. That is, the first step height SH1 represents the difference between the first analog output signals 40A1 generated by the first DAC circuit 41 based on digital input values ​​incremented by 1. Specifically, the first step height SH1 can be set by the first amplification factor of the first amplifier 46.

[0050] The second step height SH2 represents the minimum difference between the second analog output signals 40A2 generated by the second DAC circuit 42. That is, the second step height SH2 represents the difference between the second analog output signals 40A2 generated by the second DAC circuit 42 based on digital input values ​​incremented by 1. Specifically, the second step height SH2 can be set by the second amplification factor of the second amplifier 48.

[0051] The first operating range OR1 represents the range of the first analog output signal 40A1 that can be generated by the first DAC circuit 41. That is, the first operating range OR1 is determined by the first DAC circuit 41 based on the maximum digital input value (2). n The difference between the first analog output signal 40A1 generated by the minimum digital input value (-1) and the minimum digital input value (0). Specifically, the first operating range OR1 is defined by the bit depth (n) of the first DAC 45 and the first amplification of the first amplifier 46.

[0052] The second operating range OR2 represents the range of the second analog output signal 40A2 that can be generated by the second DAC circuit 42. That is, the second operating range OR2 is determined by the second DAC circuit 42 based on the maximum digital input value (2...). m The difference between the second analog output signal 40A2 generated by the minimum digital input value (-1) and the minimum digital input value (0). Specifically, the second operating range OR2 is defined by the bit depth (m) of the second DAC 47 and the second amplification of the second amplifier 48.

[0053] The first DAC circuit 41 converts the first digital deflection signal 40D1 into a first analog output signal 40A1. The accuracy of this conversion process is defined by the difference between the actual first analog output signal 40A1 and the ideal first analog output signal, with better accuracy achieved through a smaller difference. For example, the ideal behavior of the first DAC circuit 41 would be to output an ideal equidistant step signal. However, in practice, the actual behavior of the first DAC circuit 41 deviates from the ideal behavior, resulting in an approximately equidistant step signal as the output signal.

[0054] The second DAC circuit 42 converts the second digital deflection signal 40D2 into a second analog output signal 40A2. The accuracy of this conversion process is defined by the difference between the actual second analog output signal 40A2 and the ideal second analog output signal, with better accuracy achieved through a smaller difference. For example, the ideal behavior of the second DAC circuit 42 would be to output an ideal equidistant step signal. However, in practice, the actual behavior of the second DAC circuit 42 deviates from the ideal behavior, resulting in an approximately equidistant step signal as the output signal.

[0055] The accuracy of the first DAC circuit 41 in converting the first digital deflection signal 40D1 into the first analog output signal 40A1 is greater than the accuracy of the second DAC circuit 42 in converting the second digital deflection signal 40D2 into the second analog output signal 40A2. In other words, the accuracy requirements for the second DAC circuit 42 are not as stringent as those for the first DAC circuit 41.

[0056] The first DAC 45 converts the first digital deflection signal 40D1 into a first analog intermediate signal 40I1. The accuracy of this conversion process is defined by the difference between the actual first analog intermediate signal 40I1 and the ideal first analog intermediate signal, with better accuracy achieved through a smaller difference. For example, the ideal behavior of the first DAC 45 would be to output an ideal equidistant step signal. However, in practice, the actual behavior of the first DAC 45 deviates from the ideal behavior, resulting in an approximately equidistant step signal as the output signal.

[0057] The second DAC 47 converts the second digital deflection signal 40D2 into a second analog intermediate signal 40I2. The accuracy of this conversion process is defined by the difference between the actual second analog intermediate signal 40I2 and the ideal second analog intermediate signal, with better accuracy achieved through a smaller difference. For example, the ideal behavior of the second DAC 47 would be to output an ideal equidistant step signal. However, in practice, the actual behavior of the second DAC 47 deviates from the ideal behavior, resulting in an approximately equidistant step signal as the output signal.

[0058] The accuracy of the first DAC 45 in converting the first digital deflection signal 40D1 into the first analog intermediate signal 40I1 is greater than the accuracy of the second DAC 47 in converting the second digital deflection signal 40D2 into the second analog intermediate signal 40I2. In other words, the accuracy requirements for the second DAC 47 are not as stringent as those for the first DAC 45.

[0059] Both the first DAC circuit 41 and the second DAC circuit 42 contribute to the analog output signal 40A provided to the field generator 44 and the resulting deflection of the charged particle beam 2. Figure 3 As shown, the first DAC circuit 41 and the second DAC circuit 42 can be configured and set such that the contribution of the first analog output signal 40A1 to the analog output signal 40A is small but precise, while the contribution of the second analog output signal 40A2 to the analog output signal 40A is large and not necessarily as precise as the contribution of the first analog output signal 40A1. This configuration can be achieved by configuring the first DAC circuit 41 to have a high bit depth (e.g., 12 bits) and by setting the first amplification rate to be less than the second amplification rate.

[0060] like Figure 3 As shown, the first DAC circuit 41 and the second DAC circuit 42 can be configured and set such that the first operating range OR1 is approximately equal to the second step height SH2. Specifically, the first amplification and the second amplification can be selected such that the first operating range OR1 is approximately equal to the second step height SH2. Other configurations are possible. For example, the first DAC circuit 41 and the second DAC circuit 42 can be configured and set such that the first operating range OR1 is at least half of the second step height SH2.

[0061] According to another example, the first DAC circuit 41 and the second DAC circuit 42 can be configured and set such that the ratio of the second operating range OR2 to the first operating range OR1 reaches at least 10, particularly at least 100, and more particularly at least 200. Specifically, the first amplification and the second amplification can be selected such that the ratio of the second operating range OR2 to the first operating range OR1 reaches at least 10, particularly at least 100, and more particularly at least 200.

[0062] The advantage of this configuration and setup is that the first DAC circuit 41 can be used to generate a high-precision component of the analog output signal 40A, which is used to record a high-resolution image with high precision, while maintaining (i.e., keeping constant) the low-precision component of the analog output signal 40A generated by the second DAC circuit 42. On the other hand, a large field of view is obtained from the low-precision component of the analog output signal 40A generated by the second DAC circuit 42.

[0063] refer to Figure 4 The contributions of the first analog output signal 40A1 and the second analog output signal 40A2 to the analog output signal 40A are related to their respective contributions to the deflection of the charged particle beam 2. Figure 4 The sample 3 is shown with multiple regions of interest (ROIs) 61, 62. ROIs 61, 62 are located on the surface of the sample 3. The surface of the sample 3 is located in the focal plane 6. The ROIs 61, 62 are far apart, that is, the ROIs 61, 62 are spaced apart by a distance d, which is large compared to the first scan range SR1 provided by the first DAC circuit 41.

[0064] The first scanning range SR1 represents the length of a region in the focal plane 6 of the objective lens 12, the length of which can be scanned by changing the first digital deflection signal 40D1 while maintaining the second digital deflection signal 40D2. In other words, the first scanning range SR1 represents the length of the region (in the focal plane 6 of the objective lens 12) where the charged particle beam 2 can be guided by deflecting it, achieved by changing the first digital deflection signal 40D1 without changing the second digital deflection signal 40D2.

[0065] Similarly, the second scanning range SR2 represents the length of a region in the focal plane 6 of the objective lens 12, the length of which can be scanned by changing the second digital deflection signal 40D2 while maintaining the first digital deflection signal 40D1. In other words, the second scanning range SR2 represents the length of the region (in the focal plane 6 of the objective lens 12) that can be guided by deflecting the charged particle beam 2, this deflection being achieved by changing the second digital deflection signal 40D2 without changing the first digital deflection signal 40D1.

[0066] Depend on Figure 4 The double arrows in the diagram indicate the scanning region (x; 0), which is the area within the focal plane 6 of the objective lens 12. The first value in parentheses represents a specific value of the first digital deflection signal 40D1; and the second value in parentheses represents a specific value of the second digital deflection signal 40D2. By changing the first digital deflection signal 40D1 (represented by the variable x ranging from 0 to n-1, where n is the bit depth of the first DAC circuit 41) while maintaining the second digital deflection signal 40D2 at a value of 0 (represented by the specific value 0), the charged particle beam 2 can be directed to the position of the scanning region (x; 0). The length of the scanning region (x; 0) represents the first scanning range SR1 provided by the first DAC circuit 41 (for the specific value 0 of the second digital deflection signal 40D2).

[0067] Similarly, by Figure 4The double arrows in the diagram indicate the scanning region (x; 1), which is the area within the focal plane 6 of the objective lens 12. By changing the first digital deflection signal 40D1 (represented by the variable x ranging from 0 to n-1, where n is the bit depth of the first DAC circuit 41) while maintaining the second digital deflection signal 40D2 at a value of 1 (represented by a specific value 1), the charged particle beam 2 can be directed to the position of the scanning region (x; 1). The length of the scanning region (x; 1) represents the first scanning range SR1 provided by the first DAC circuit 41 (for the specific value 1 of the second digital deflection signal 40D2).

[0068] Similarly, by Figure 4 The double arrows in the diagram indicate the scanning region (x; 2), which is the region in the focal plane 6 of the objective lens 12. By changing the first digital deflection signal 40D1 (represented by the variable x ranging from 0 to n-1, where n is the bit depth of the first DAC circuit 41) while maintaining the second digital deflection signal 40D2 at a value of 2 (represented by a specific value 2), the charged particle beam 2 can be directed to the position of the scanning region (x; 2). The length of the scanning region (x; 2) represents the first scanning range SR1 provided by the first DAC circuit 41 (for the specific value 2 of the second digital deflection signal 40D2).

[0069] The indicated charged particle beam trajectory (0; m-1) is used to show the scan range SR2 provided by the second DAC circuit 42, wherein a specific value m-1 of the second digital deflection signal 40D2 indicates the maximum possible input value of the second digital deflection signal 40D2 based on the bit depth m of the second DAC circuit 42.

[0070] Figure 5 A method according to an embodiment of the second aspect of the present invention is illustrated. The method relates to operating the aforementioned charged particle beam system 1. In particular, the method relates to advantageously configuring as follows: Figure 4 The eccentric rotor system 40 of sample 3 is shown, with ROIs 61 and 62 far apart.

[0071] In step S1, the coordinates of ROIs 61 and 62 on sample 3 are obtained. These coordinates represent the location of the boundaries of ROIs 61 and 62, thus allowing the determination of characteristics of ROIs 61 and 62, such as their size and shape. The coordinate data representing the coordinates of ROIs 61 and 62 can be obtained by the controller 20 of the charged particle beam system 1, for example, through data transmission from another device, through data transmission via a network (such as the Internet), or by reading from a data storage device. For this purpose, the charged particle beam system 1 may include a data interface for receiving coordinate data and a data storage device for storing the coordinate data.

[0072] The coordinates of ROIs 61 and 62 can be determined first using any type of method or instrument. For example, the coordinates of ROIs 61 and 62 can be obtained using optical microscopy, dark-field microscopy, charged particle beam microscopy, atomic force microscopy, etc. In particular, the coordinates of ROIs 61 and 62 can be obtained using charged particle beam system 1. Furthermore, the coordinates of ROIs 61 and 62 can be determined using the design information of sample 3 and ROIs 61 and 62. For example, during the fabrication process, sample 3, including ROIs 61 and 62, can be generated based on the design information. The design information may include information about the relative positions of ROIs 61 and 62, the distance between ROIs 61 and 62, etc. Additionally, for example in chip manufacturing, ROIs 61 and 62 are located on a wafer (i.e., sample 3), and this wafer is fabricated and transported by an automated system. Therefore, the orientation and position of the wafer are typically stored in the controller of the automated system, and the positions of ROIs 61 and 62 on the wafer are typically stored in the design information. Therefore, the coordinates of the ROIs can be provided by the controller of the automated system.

[0073] In steps S2 and S3, the first DAC circuit 41 and the second DAC circuit 42 of the bias rotor system 40 are configured based on the obtained coordinates of ROIs 61 and 62. Specifically, in step S2, the first amplification rate of the first amplifier 46 is configured; and in step S3, the second amplification rate of the second amplifier 48 is configured. The controller 20 can be configured to determine the distance between ROIs 61 and 62, as well as the size, shape, etc., of ROIs 61 and 62, which are used to configure the first DAC circuit 41 and the second DAC circuit 42. In particular, the controller 20 can be configured to determine the setting of the first DAC circuit 41 (the first amplification rate of the first amplifier 46) and the setting of the second DAC circuit 42 (the second amplification rate of the second amplifier 48) based on the obtained coordinates of ROIs 61 and 62, thereby achieving a predefined set of constraints.

[0074] For example, according to Figure 4 As illustrated, the first DAC circuit 41 (specifically, the first amplification rate of the first amplifier 46) can be set (i.e., selected) such that the first scan range SR1 is at least as large as the largest of the ROIs 61 and 62. Therefore, each of the ROIs 61 and 62 can be scanned with high precision and high resolution, i.e., by changing the first digital deflection signal (40D1) while maintaining the second digital deflection signal (40D2). Furthermore, the second DAC circuit 42 (specifically, the second amplification rate of the second amplifier 48) can be set (i.e., selected) such that the second scan range SR2 is at least as large as the maximum distance between the ROIs 61 and 62. Therefore, all ROIs 61 and 62 can be scanned without moving the stage 4. That is, images of the ROIs 61 and 62 can be recorded while the stage 4 is held in the appropriate position.

[0075] Subsequently, in step S4, images of ROIs 61 and 62 are recorded using the configured procedure. Specifically, the charged particle beam 2 can be scanned over ROIs 61 and 62, and the interaction products of the charged particle beam 2 with the sample 3 (e.g., backscattered or secondary electrons, backscattered or secondary ions, radiation, etc.) can be detected to record images. Using the above configuration, images of each of ROIs 61 and 62 can be recorded by scanning the charged particle beam 2 over the respective ROI, which is achieved by changing the first digital deflection signal 40D1 and maintaining the second digital deflection signal 40D2. For example, refer to... Figure 4 The image of ROI 61 can be recorded by changing the first digital deflection signal 40D1 from 0 to n-1 and maintaining the second digital deflection signal 40D2 at 0. In order to record the image of ROI 62, when scanning the charged particle beam 2 on ROI 62 by changing the first digital deflection signal 40D1, the second digital deflection signal 40D2 changes to m-1 and is maintained at m-1.

[0076] Refer again Figure 2 The deflector system 50 of the deflection system 13 is constructed in the same manner as the deflector system 40. However, the deflector system 50 deflects the charged particle beam 2 in a different direction than the deflector system 40. Therefore, the deflection system 13 can be configured to deflect the charged particle beam 2 in multiple different deflection directions.

[0077] Although having the same structure as deflection system 40, deflection system 50 and its components can be configured and set independently of deflection system 40. Deflection system 50 includes a first DAC circuit 51 similar to the first DAC circuit 41, a second DAC circuit 52 similar to the second DAC circuit 42, an adder 53 similar to adder 43, and a field generator 54 similar to field generator 44. For brevity, a more detailed description of deflection system 50 is omitted; refer to the corresponding deflection system 40 and its components.

[0078] refer to Figures 6 to 9 An exemplary embodiment of the method according to a third aspect of the present invention is described. The method includes recording multiple images on sample 3 representing multiple different regions of interest (ROIs) A, B, and C. Figure 6 Examples of ROIA, B, and C are shown on sample 3.

[0079] Recording multiple images of ROIs A, B, and C involves scanning a charged particle beam 2 across multiple scanning regions, thereby achieving a set of predetermined constraints. Figure 6Examples of scanning areas A1 to A4, B1 to B4, C1 to C4 on sample 3 are shown, along with the scanning sequence of scanning areas A1 to A4, B1 to B4, C1 to C4.

[0080] Scanning the charged particle beam 2 over each of the scanning regions A1 to A4, B1 to B4, and C1 to C4 includes: guiding the charged particle beam 2 to multiple different locations within the corresponding scanning region; detecting the interaction products between the charged particle beam 2 and the sample 3 during scanning the charged particle beam over the corresponding scanning region; and storing measurement data based on the detection rate. Therefore, the scanning region is the area of ​​the sample to which the charged particle beam 2 is guided for recording a portion of an image including the region of interest within that scanning region.

[0081] The constraints include: each ROI comprises multiple scan regions. Figure 6 In the example shown, ROI A includes four scan regions A1, A2, A3, and A4; ROI B includes four scan regions B1, B2, B3, and B4; and ROI C includes four scan regions C1, C2, C3, and C4. Generally, the number of scan regions for each ROI can be different. In practice, the number of scan regions for each ROI will be much greater than four. For example, each region of interest may include at least 10 or at least 100 scan regions. That is, the number of scan regions for each ROI can be at least 10 or at least 100.

[0082] For example, such as Figure 6 As shown, the scan areas A1 to A4, B1 to B4, and C1 to C4 can be line segments of the ROI. However, any part of the ROI can be selected as a scan area. The maximum distance between adjacent scan areas belonging to the same ROI should be at most 200 nm, 100 nm, 50 nm, 20 nm, or 10 nm. Otherwise, the image resolution will be poor.

[0083] The constraints further include: every two scan regions to be scanned consecutively must be separated by a first minimum distance, which is at least 100 nm. The expression "consecutive" means directly one after another in time, without interruption by the scanning of any other scan region. In other words, the two scan regions to be scanned consecutively are the scan region to be scanned and the scan region that is directly scanned after that scan region (the next one). Figure 6 In the diagram, the scanning order of scanning areas A1 to A4, B1 to B4, and C1 to C4 is indicated by arrows connecting scanning areas A1 to A4, B1 to B4, and C1 to C4. Specifically, in... Figure 6The scanning order of the scanned regions A1 to A4, B1 to B4, and C1 to C4 shown in the example is: A1, B1, C1, A2, B2, C2, A3, B3, C3, A4, B4, C4. All two scanned regions to be scanned consecutively are (A1, B1), (B1, C1), (C1, A2), (A2, B2), (B2, C2), (C2, A3), (A3, B3), (B3, C3), (C3, A4), (A4, B4), (B4, C4).

[0084] According to the constraints, every two scan regions to be scanned consecutively must be at least separated by a first minimum distance. Specifically, this means that every two scan regions to be scanned consecutively must be separated by a minimum distance that is at least equal to the first minimum distance. As an illustrative example, Figure 7 The diagram shows the shortest distances between two scan regions to be scanned consecutively in the first few iterations: d1 represents the shortest distance between the two scan regions (A1, B1) in the first iteration; d2 represents the shortest distance between the two scan regions (B1, C1) in the second iteration; and d3 represents the shortest distance between the two scan regions (C1, A2) in the third iteration. Since the distance between each pair of scan regions to be scanned consecutively is quite large, the charge accumulated in one scan region has almost no effect on the scanning of the charged particle beam in the next scan region.

[0085] This effect can be improved by increasing the first minimum distance. For example, the first minimum distance can be at least 200 nm, at least 500 nm, or at least 1000 nm.

[0086] The constraint further includes that every two scan regions to be scanned consecutively belong to different regions of interest within the region of interest. Figure 6 In the example shown, the order of ROIs associated with the scanning order of the scanned regions is: A, B, C, A, B, C, A, B, C, A, B, C.

[0087] Figure 8 Further details of the regions of interest are shown. ROIs A, B, and C do not overlap. That is, the boundaries of ROIs A, B, and C, shown as solid lines, do not intersect each other. Specifically, ROIs can be spaced at least 10 nm, at least 50 nm, at least 100 nm, at least 500 nm, or at least 1000 nm apart. In other words, the shortest distance between adjacent ROIs can reach at least 10 nm, at least 50 nm, at least 100 nm, at least 500 nm, or at least 1000 nm. Figure 8In the diagram, the shortest distance between ROI A and ROI B is denoted as dAB; the shortest distance between ROI B and ROI C is denoted as dBC; and the shortest distance between ROI A and ROI C is denoted as dAC.

[0088] Alternatively, ROIs can be spaced at least half the size of the smallest ROI. That is, the shortest distance between the boundaries of adjacent ROIs is at least half the size of the smallest ROI. For example, the size of an ROI can be its average diameter.

[0089] This method has the following effect: it allows the recording of multiple images with reduced interference caused by charge accumulation in the sample using a charged particle beam. While the example above only shows three images and three ROIs A, B, and C, this method can be performed on two or more images and ROIs separately. Although the example above only refers to four scan regions per ROI, the method can be performed using any number of scan regions per ROI, with at least two.

[0090] The recorded images can be displayed, for example, by output device 33.

[0091] Figure 9 This is a flowchart illustrating another embodiment of a method according to a third aspect of the present invention, configured using a method according to a second aspect of the present invention. Figure 1 The charged particle beam system shown is 1.

[0092] In step S11, the coordinates of regions of interest A, B, and C are obtained. This step corresponds to... Figure 5 Step S1 of the method shown herein is described herein.

[0093] Following step S11, in step S12, the scanning regions A1 to A4, B1 to B4, and C1 to C4, and the scanning order, are determined based on the coordinates of ROIs A, B, and C obtained in step S11. The scanning order defines the scanning sequence of the scanning regions. Determining the scanning regions A1 to A4, B1 to B4, and C1 to C4, and the scanning order, achieves predetermined constraints. (See reference...) Figures 6 to 8 The constraints described include: each ROI A, B, C includes multiple scanning regions A1 to A4, B1 to B4, C1 to C4; every two scanning regions to be scanned consecutively are at least separated by a first minimum distance, the first minimum distance being at least 100 nm; and every two scanning regions to be scanned consecutively belong to different regions of interest in ROI A, B, C.

[0094] Based on the coordinates of ROI A, B, C, the scan region and scan sequence can be determined using the controller 20 of the charged particle beam system 1 or any other processor. The scan region and scan sequence can be determined prior to scanning the scan region. Alternatively, the scan region and scan sequence can be determined in parallel with scanning the scan region as needed. Various methods, algorithms, and apparatuses can be used to determine the scan region and scan sequence. However, for the method at hand, the specific implementation of determining the scan region and scan sequence is irrelevant as long as predefined constraints are met.

[0095] Following step S12, in step S13, the next scan region to be scanned is selected from the scan regions A1 to A4, B1 to B4, and C1 to C4 according to the scan sequence. The selection of the scan region includes changing the second digital deflection signal 40D2. The selection of the scan region may also include changing the second digital deflection signal 50D2 of the deflector system 50.

[0096] Following step S13, in step S14, the charged particle beam 2 is scanned over the selected scanning area. Scanning the charged particle beam 2 over the selected scanning area includes: converting a first digital deflection signal 40D1 into a first analog output signal 40A1; converting a second digital deflection signal 40D2 into a second analog output signal 40A2; generating an analog deflection signal 40A based on the sum of the first analog output signal 40A1 and the second analog output signal 40A2; deflecting the charged particle beam 2 using the analog deflection signal 40A; and changing the first digital deflection signal 40D1 while maintaining the second digital deflection signal 40D2.

[0097] The scanning of the charged particle beam 2 in the selected scanning area may further include: converting the first digital deflection signal 50D1 into a first analog output signal 50A1; converting the second digital deflection signal 50D2 into a second analog output signal 50A2; generating an analog deflection signal 50A based on the sum of the first analog output signal 50A1 and the second analog output signal 50A2; using the analog deflection signal 50A to deflect the charged particle beam 2; and changing the first digital deflection signal 50D1 while maintaining the second digital deflection signal 50D2.

[0098] Following step S14, in step S15, it is determined whether all scanned regions A1 to A4, B1 to B4, and C1 to C4 have been scanned. If all scanned regions A1 to A4, B1 to B4, and C1 to C4 have been scanned, the images of regions of interest A, B, and C are completely recorded, and the method ends. If not all scanned regions A1 to A4, B1 to B4, and C1 to C4 have been scanned, steps S13 to S15 are repeated, thereby scanning another of the scanned regions A1 to A4, B1 to B4, and C1 to C4. Steps S13 to S15 are repeated until all scanned regions A1 to A4, B1 to B4, and C1 to C4 have been scanned, i.e., until all images of regions of interest A, B, and C are completely recorded.

[0099] In some implementations, the processing unit 32 and the controller 20 may each include one or more data processors for processing data, one or more storage devices for storing data, and / or one or more computer programs including instructions that, when executed by the processing unit 32 or the controller 20, cause the processing unit 32 or the controller 20 to perform the above-described process.

[0100] In some implementations, processing unit 32 and controller 20 may each include digital electronic circuitry, computer hardware, firmware, software, or any combination thereof. Features related to data processing may be implemented in a computer program product tangibly contained in an information carrier, such as a machine-readable storage device, for execution by a programmable processor; and method steps may be executed by a programmable processor executing instruction programs to perform the functions of the described embodiments by manipulating input data and generating outputs. Alternatively or additionally, program instructions may be encoded on propagation signals, which are artificially generated signals, such as machine-generated electrical, optical, or electromagnetic signals, generated to encode information for transmission to a suitable receiver device for execution by a programmable processor.

[0101] In some implementations, the operations associated with the data processing described herein may be performed by one or more programmable processors executing one or more computer programs to perform the functions described herein. The computer programs may be written in any form of programming language, including compiled or interpreted languages, and may be deployed in any form, including as standalone programs or as modules, components, subroutines, or other units suitable for use in a computing environment.

[0102] For example, processing unit 32 and controller 20 may each be configured to be suitable for the execution of a computer program and may include, for example, general-purpose and special-purpose microprocessors, and any one or more processors of any kind of digital computer. Typically, the processor receives instructions and data from read-only memory or random access memory, or both. The components of a computer include one or more processors for executing instructions and one or more storage area devices for storing instructions and data. Typically, a computer will also include, or be operatively coupled to, receiving data from and / or transferring data to one or more machine-readable storage media, such as hard disk drives, magnetic disks, magneto-optical disks, or optical disks. Machine-readable storage media suitable for implementing computer program instructions and data include various forms of non-volatile storage areas, including, for example, semiconductor storage devices such as EPROM, EEPROM, and flash memory storage devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks.

[0103] In some implementations, the processes for operating the charged particle beam system described above can be implemented using software that executes on one or more mobile computing devices, one or more local computing devices, and / or one or more remote computing devices. For example, the software is formed within one or more computer programs that execute on one or more programmed or programmable computer systems, which can be mobile computing devices, local computing devices, or remote computing systems (which can be various architectures such as distributed, client / server, or grid computing). Each computer system includes at least one processor, at least one data storage system (including volatile and non-volatile memory and / or storage elements), at least one wired or wireless input device or port, and at least one wired or wireless output device or port.

[0104] In some implementations, the software may be provided on a medium such as a CD-ROM, DVD-ROM, or Blu-ray disc, readable by a general-purpose or special-purpose programmable computer, or transmitted over a network (encoded in a propagation signal) to a computer executing the software. The functionality may be executed on a dedicated computer or using dedicated hardware, such as a coprocessor. The software may be implemented in a distributed manner, where different parts of the computation specified by the software are executed by different computers. Each such computer program is preferably stored on or downloaded to a storage medium or device readable by a general-purpose or special-purpose programmable computer (e.g., solid-state memory or medium, or magnetic or optical medium) for configuring and operating the computer when the computer system reads the storage medium or device to execute the program described herein. The system of the present invention can also be considered as a computer-readable storage medium configured with a computer program, wherein such a storage medium causes the computer system to operate in a specific and predefined manner to perform the functions described herein.

[0105] While this specification contains numerous specific implementation details, these should not be construed as limiting the scope of any invention or the scope that may be claimed, but rather as descriptions of features specific to particular embodiments of a particular invention. Many variations and alternative embodiments will be apparent to those skilled in the art, for example, by combining and / or exchanging features of the various embodiments. Therefore, such variations and alternative embodiments are consequently included with this invention, and the scope of the invention is limited only to the meaning of the appended claims and their equivalents.

[0106] Some features described in the context of individual embodiments in this specification may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0107] Similarly, although operations are depicted in the accompanying drawings in a specific order, this should not be construed as requiring such operations to be performed in the specific order shown or sequentially, or to perform all of the shown operations to obtain the desired result. Furthermore, the separation of various system components in the above embodiments should not be construed as requiring such separation in all embodiments.

[0108] Although the invention is defined in the appended claims, it should be understood that the invention may also be defined according to the following embodiments:

[0109] Example 1: A charged particle beam system (1), comprising:

[0110] A charged particle beam source (11) is configured to generate a charged particle beam (2);

[0111] Objective lens (12) is configured to focus the charged particle beam (2) onto the focal plane (6);

[0112] A deflection system (13) is configured to deflect a charged particle beam (2), wherein the deflection system (13) includes at least one deflector system (40, 50), wherein each deflector system (40, 50) includes:

[0113] The first DAC circuit (41) is configured to convert the first digital deflection signal (40D1) into a first analog output signal (40A1) within a first operating range (OR1) by a step of a first step height (SH1).

[0114] The second DAC circuit (42) is configured to convert the second digital deflection signal (40D2) into a second analog output signal (40A2) within a second operating range (OR2) by a step of the second step height (SH2).

[0115] Adder (43) is configured to receive a first analog output signal (40A1) and a second analog output signal (40A2), and to output an analog deflection signal (40A) based on the sum of the received first analog output signal (40A1) and the received second analog output signal (40A2).

[0116] Field generator (44) is configured to receive an analog deflection signal (40A) and use the received analog deflection signal (40A) to generate a magnetic field and / or an electric field to deflect the charged particle beam (2).

[0117] The charged particle beam system (1) also includes:

[0118] The controller (20) is configured to generate a first digital deflection signal (40D1) and a second digital deflection signal (40D2) for each deflector system (40, 50).

[0119] Example 2: The charged particle beam system (1) according to Example 1,

[0120] The first operating range (OR1) is approximately equal to the second step height (SH2).

[0121] Example 3: Charged particle beam system (1) according to Example 1 or 2,

[0122] The ratio of the second operating range (OR2) to the first operating range (OR1) is at least 10, particularly at least 100, and more particularly at least 200.

[0123] Example 4: A charged particle beam system (1) according to any one of Examples 1 to 3;

[0124] The accuracy of the first digital deflection signal (40D1) converted into the first analog output signal (40A1) by the first DAC circuit (41) is greater than the accuracy of the second digital deflection signal (40D2) converted into the second analog output signal (40A2) by the second DAC circuit (42).

[0125] Example 5: A charged particle beam system (1) according to any one of Examples 1 to 4;

[0126] The first DAC circuit (41) includes a first DAC (45) and a first amplifier (46). The first DAC (45) is configured to convert a first digital deflection signal (40D1) into a first analog intermediate signal (40I1). The first amplifier (46) is configured to amplify the first analog intermediate signal (40I1) by using a first amplification factor to generate a first analog output signal (40A1).

[0127] The second DAC circuit (42) includes a second DAC (47) and a second amplifier (48). The second DAC (47) is configured to convert the second digital deflection signal (40D2) into a second analog intermediate signal (40I2). The second amplifier (48) is configured to amplify the second analog intermediate signal (40I2) by using a second amplification factor to generate a second analog output signal (40A2).

[0128] Example 6: The charged particle beam system (1) according to Example 5,

[0129] The first magnification limits the first step height (SH1).

[0130] The second magnification limits the second step height (SH2).

[0131] The bit depth and first amplification of the first DAC (45) define the first operating range (OR1).

[0132] The bit depth and second amplification of the second DAC (47) define the second operating range (OR2).

[0133] Example 7: Charged particle beam system (1) according to Example 5 or 6,

[0134] The first and second magnifications are selected such that the first operating range (OR1) is approximately equal to the second step height (SH2).

[0135] Example 8: A charged particle beam system (1) according to any one of Examples 5 to 7;

[0136] The first and second magnifications are selected such that the ratio of the second operating range (OR2) to the first operating range (OR1) is at least 10, particularly at least 100, and more particularly at least 200.

[0137] Example 9: A charged particle beam system (1) according to any one of Examples 5 to 8;

[0138] The accuracy of the first digital deflection signal (40D1) converted into the first analog intermediate signal (40I1) by the first DAC (45) is greater than the accuracy of the second digital deflection signal (40D2) converted into the second analog intermediate signal (40I2) by the second DAC (47).

[0139] Example 10: A charged particle beam system (1) according to any one of Examples 5 to 9;

[0140] The bit depth of the first DAC (45) is greater than that of the second DAC (47).

[0141] Example 11: A charged particle beam system (1) according to any one of Examples 1 to 10;

[0142] The deflection system (13) is configured to deflect the charged particle beam (2) so that the charged particle beam (2) can be guided to multiple different positions in the focal plane (6).

[0143] Example 12: A method of operating a charged particle beam system (1) according to any one of Examples 1 to 11, the method comprising:

[0144] Obtain the coordinates of multiple regions of interest (61, 62) on sample (3);

[0145] The first DAC circuit (41) is configured such that the first scanning range (SR1) provided by the first DAC circuit (41) is at least as large as the largest of the regions of interest (61, 62), the first scanning range (SR1) representing the length of a region in the focal plane (6) of the objective lens (12), the length of which can be scanned by changing the first digital deflection signal (40D1) while maintaining the second digital deflection signal (40D2);

[0146] The second DAC circuit (42) is configured such that the second scanning range (SR2) provided by the second DAC circuit (42) is at least as large as the maximum distance (d) between the regions of interest (61, 62), the second scanning range (SR2) representing the length of a region in the focal plane (6) of the objective lens (12), the length of which can be scanned by changing the second digital deflection signal (40D2) while maintaining the first digital deflection signal (40D1); and

[0147] Use the configured settings to record images of regions of interest (61, 62).

[0148] Example 13: According to the method of Example 12, recording each image includes:

[0149] The charged particle beam (2) is scanned over the region of interest associated with the corresponding image by changing the first digital deflection signal (40D1) and maintaining the second digital deflection signal (40D2).

[0150] The interaction products between the charged particle beam (2) and the sample (3) were detected during the scan.

[0151] Example 14: According to the method of Example 12 or 13, the recording of images further includes:

[0152] The next region of interest is selected by changing the second digital deflection signal (40D2).

[0153] Example 15: The method according to any one of Examples 12 to 14, wherein recording the image further includes:

[0154] Hold the stage (4) in the appropriate position, and hold the sample (3) in place.

[0155] Example 16: Operation of any one of Examples 12 to 15. Method of charged particle beam system (1) according to any one of Examples 5 to 10, wherein the configuration of the first DAC circuit (41) includes setting a first amplification rate; and the configuration of the second DAC circuit (42) includes setting a second amplification rate.

[0156] Example 17: A computer program including instructions that, when executed by a controller of a charged particle beam system (1) according to any one of Examples 1 to 11, enable the charged particle beam system (1) to perform the method according to any one of Examples 12 to 16.

[0157] Example 18: A method for recording multiple images representing different regions of interest of a sample, the method comprising:

[0158] Record multiple images representing multiple different regions of interest (A, B, C) on sample (3), including:

[0159] The charged particle beam was scanned over multiple scanning regions (A1 to A4, B1 to B4, C1 to C4) (2).

[0160] Each of the regions of interest (A, B; C) includes multiple scan regions (A1 to A4, B1 to B4, C1 to C4).

[0161] Wherein, every two scan regions to be scanned consecutively are at least separated by a first minimum distance, the first minimum distance being at least 100 nm, and

[0162] Each pair of scanned regions to be scanned consecutively belongs to a different region of interest (A, B, C).

[0163] Example 19: The method according to Example 18 further includes:

[0164] Multiple scanning regions (A1 to A4, B1 to B4, C1 to C4) and the scanning order are determined based on the coordinates of multiple regions of interest (A, B, C).

[0165] The scanning order defines the scanning sequence of the scanning areas (A1 to A4, B1 to B4, C1 to C4).

[0166] Example 20: According to the method of Example 18 or 19, scanning the charged particle beam (2) in each scanning region (A1 to A4, B1 to B4, C1 to C4) includes:

[0167] The first digital deflection signal (40D1) is converted into the first analog output signal (40A1);

[0168] The second digital deflection signal (40D2) is converted into the second analog output signal (40A2);

[0169] An analog deflection signal (40A) is generated based on the sum of the first analog output signal (40A1) and the second analog output signal (40A2); and

[0170] The charged particle beam (2) is deflected using an analog deflection signal (40A).

[0171] Example 21: According to the method of Example 20, each of the upper-scanning charged particle beams (2) in the scanning regions (A1 to A4, B1 to B4, C1 to C4) further includes:

[0172] While maintaining the second digital deflection signal (40D2), the first digital deflection signal (40D1) is changed.

[0173] Example 22: According to the method of Example 20 or 21, the recording of multiple images further includes:

[0174] Within the scanning areas (A1 to A4, B1 to B4, C1 to C4), the next scanning area to be scanned is selected by changing the second digital deflection signal (40D2).

[0175] Example 23: The method according to any one of Examples 18 to 22, wherein the first minimum distance reaches at least 200 nm, at least 500 nm, or at least 1000 nm.

[0176] Example 24: The method according to any one of Examples 18 to 23, wherein the scanning regions (A1 to A4, B1 to B4, C1 to C4) are line segments of the regions of interest (A, B, C).

[0177] Example 25: According to the method of any one of Examples 18 to 24, the maximum distance between adjacent scan regions belonging to the same region of interest (A, B, C) reaches at most 200 nm, at most 100 nm, at most 50 nm, at most 20 nm, or at most 10 nm.

[0178] Example 26: The method according to any one of Examples 18 to 25, wherein the regions of interest (A, B, C) do not overlap with each other.

[0179] Example 27: The method according to any one of Examples 18 to 26, wherein the regions of interest (A, B, C) are spaced at least 10 nm, at least 50 nm, at least 100 nm, at least 500 nm, or at least 1000 nm apart.

[0180] Example 28: The method according to any one of Examples 18 to 27, wherein the regions of interest (A, B, C) are at least half the size of the smallest of the regions of interest (A, B, C).

[0181] Example 29: The method according to any one of Examples 18 to 28, wherein recording multiple images further includes:

[0182] During the scanning of the charged particle beam (2) across the scanning regions (A1 to A4, B1 to B4, C1 to C4), the interaction products between the charged particle beam (2) and the sample (3) are detected; and

[0183] Measurement data are stored based on the detection rate of the interaction products between the charged particle beam (2) and the sample (3).

[0184] Example 30: The method according to any one of Examples 18 to 29, wherein each region of interest (A, B, C) includes at least 10 or at least 100 scan regions (A1 to A4, B1 to B4, C1 to C4).

[0185] Example 31: The method according to any one of Examples 18 to 30 further includes:

[0186] Display image.

[0187] Example 32: The method according to any one of Examples 18 to 31, wherein the method is performed using a charged particle beam system (1) according to any one of Examples 1 to 11.

[0188] Example 33: A computer program including instructions that, when executed by a controller of a charged particle beam system, particularly a controller (20) of a charged particle beam system (1) according to any one of Examples 1 to 11, enable the charged particle beam system to perform the method according to any one of Examples 18 to 32.

Claims

1. A method for operating a charged particle beam system, The charged particle beam system includes: A charged particle beam source is configured to generate a charged particle beam; Objective lenses are configured to focus the charged particle beam onto the focal plane; A deflection system is configured to deflect the charged particle beam, wherein the deflection system includes at least one deflector system, wherein each deflector system includes: A first DAC circuit is configured to convert a first digital deflection signal into a first analog output signal within a first operating range (OR1) by a step of a first step height (SH1). The second DAC circuit is configured to convert the second digital deflection signal into a second analog output signal within a second operating range (OR2) by a step of a second step height (SH2). An adder is configured to receive the first analog output signal and the second analog output signal, and to output an analog deflection signal based on the sum of the received first analog output signal and the received second analog output signal. A field generator is configured to receive the analog deflection signal and use the received analog deflection signal to generate a magnetic field and / or an electric field to deflect the charged particle beam. The charged particle beam system further includes: The controller is configured to generate the first digital deflection signal and the second digital deflection signal for each deflector system. The method includes: Obtain the coordinates of multiple regions of interest on the sample; The first DAC circuit is configured such that the first scan range (SR1) provided by the first DAC circuit is at least as large as the largest region in the region of interest, the first scan range (SR1) representing the length of a region in the focal plane of the objective lens, the length of which can be scanned by changing the first digital deflection signal while maintaining the second digital deflection signal; The second DAC circuit is configured such that the second scanning range (SR2) provided by the second DAC circuit is at least as large as the maximum distance (d) between the regions of interest, the second scanning range (SR2) representing the length of a region in the focal plane of the objective lens, the length of which can be scanned by changing the second digital deflection signal while maintaining the first digital deflection signal; and The configured settings are used to record images of the region of interest.

2. The method of claim 1, wherein, Each image record includes: The charged particle beam is scanned over the region of interest associated with the corresponding image by changing the first digital deflection signal and maintaining the second digital deflection signal. The interaction products between the charged particle beam and the sample are detected during the scan.

3. The method according to claim 1, wherein, The recorded images also include: The next region of interest is selected by changing the second digital deflection signal.

4. The method of claim 1, wherein, The recorded images also include: The stage is held in place, and the stage holds the sample.

5. The method according to claim 1, wherein the first DAC circuit comprises: A first DAC and a first amplifier, the first DAC being configured to convert the first digital deflection signal into a first analog intermediate signal, and the first amplifier being configured to amplify the first analog intermediate signal by using a first amplification factor to generate the first analog output signal. The second DAC circuit includes a second DAC and a second amplifier. The second DAC is configured to convert the second digital deflection signal into a second analog intermediate signal, and the second amplifier is configured to amplify the second analog intermediate signal by using a second amplification factor to generate the second analog output signal. The configuration of the first DAC circuit includes setting the first amplification rate; and the configuration of the second DAC circuit includes setting the second amplification rate.

6. The method according to claim 1, wherein: The images representing different regions of interest on the sample include: The charged particle beam is scanned across multiple scanning regions. Each of the regions of interest includes a plurality of the scanned regions. Wherein, every two scan regions to be scanned consecutively are at least separated by a first minimum distance, the first minimum distance being at least 100 nm, and Each pair of scanned regions to be scanned consecutively belongs to a different region of interest within the region of interest.

7. The method according to claim 6, further comprising: The multiple scanning regions and scanning order are determined based on the coordinates of the multiple regions of interest. The scanning order defines the scanning order of the scanning region.

8. The method of claim 6, wherein scanning the charged particle beam in each of the scanning regions comprises: The first digital deflection signal is converted into the first analog output signal; The second digital deflection signal is converted into the second analog output signal; The analog deflection signal is generated based on the sum of the first analog output signal and the second analog output signal; as well as The charged particle beam is deflected using the simulated deflection signal.

9. The method of claim 8, wherein scanning the charged particle beam in each of the scanning regions further comprises: While maintaining the second digital deflection signal, the first digital deflection signal is changed.

10. The method of claim 8, wherein, Recording multiple images also includes: Within the scanning area, the next scanning area to be scanned is selected by changing the second digital deflection signal.

11. The method of claim 6, wherein the first minimum distance reaches at least 200 nm.

12. The method of claim 6, wherein the scanning region is a line segment of the region of interest.

13. The method of claim 6, wherein the maximum distance between adjacent scan regions belonging to the same region of interest reaches at most 200 nm.

14. The method of claim 6, wherein the regions of interest do not overlap with each other.

15. The method of claim 6, wherein the regions of interest are spaced at least 10 nm apart.

16. The method of claim 6, wherein the regions of interest are at least half the size of the smallest of the regions of interest.

17. The method of claim 6, wherein, Recording multiple images also includes: During the scanning of the scanning region by the charged particle beam, the interaction products between the charged particle beam and the sample are detected; and Measurement data is stored based on the detection rate of the interaction products between the charged particle beam and the sample.

18. The method of claim 6, wherein each of the regions of interest comprises at least 10 or at least 100 of the scan regions.

19. The method of claim 6, further comprising: The image is displayed.

20. A computer program comprising instructions that, when executed by a controller of a charged particle beam system, enable the charged particle beam system to perform the method of claim 1.

Images