Inspection systems, computer systems, and computer programs

Abstract

Provided is a technique capable of maintaining or improving throughput while maintaining sensitivity, regarding an inspection system using a charged particle beam device. The inspection system for performing a region inspection of a sample is provided with the charged particle beam device and a computer system. The computer system determines an operation condition of an optical adjustment using an adjustment device related to a beam of the charged particle beam device, for imaging at a plurality of inspection points in an inspection region to be subjected to the region inspection of the sample. At the time of determination, the computer system divides the inspection region into division inspection regions belonging to a group corresponding to the pattern classification, on the basis of design layout information including information on a pattern formed on the sample, and determines an execution item and an execution parameter value of the optical adjustment for each division inspection region.

Description

Technical Field

[0001] The present invention relates to technologies for imaging, observing, measuring, inspecting, evaluating, analyzing, etc. of samples such as semiconductor devices, and relates to a technology for optical adjustment of a charged particle beam device.

Background Art

[0002] In the manufacturing process of semiconductor devices, for yield improvement, measurements of the dimensional values of circuit patterns formed on wafers, inspections for the presence or absence of defects and foreign substances (sometimes collectively referred to as defects) due to pattern formation defects, etc. are performed. From the results of these measurements and inspections (sometimes collectively referred to as inspections), feedback is given to the operating parameters of the devices used in the semiconductor device manufacturing process, and checks are made as to whether there are any malfunctions in the devices or the device operating environment. For the above inspections, as a charged particle beam device, a scanning electron microscope (SEM) or the like is used. Inspection of wafers using SEM is performed for each major manufacturing process.

[0003] As a prior art example, Japanese Patent No. 5204979 (Patent Document 1) can be cited. Patent Document 1 describes that as a "method for generating an imaging recipe", there are steps of "setting input information including coordinate information of a plurality of evaluation points of a substrate to be inspected,... design layout information of a pattern,... information of default values", "determining an imaging point that can be shared by the plurality of evaluation points from the search range of the imaging point,... determining an imaging sequence", "generating an imaging recipe that shares the imaging point", and "inspecting the substrate".

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] The wafer inspection using the above-mentioned SEM mainly involves inspecting specific areas, such as patterns prone to defects during manufacturing or areas in the semiconductor device structure where defects are unacceptable. Measurement and inspection at specific areas are called point measurement or point inspection. The points that are the target of measurement or inspection may be referred to as measurement points, inspection points, measurement-inspection points, or simply points. These points refer to a two-dimensional area corresponding to the field of view (FOV). In conventional point inspection, multiple inspection points are set discretely on the sample, for example, the wafer surface, and for each inspection point, an image (for example, a 1 μm × 1 μm area) is captured at the position coordinates of the corresponding imaging point, and inspection is performed based on that image.

[0006] However, in recent years, the introduction of extreme ultraviolet (EUV) lithography has led to the miniaturization of patterns, and the required precision of pattern formation has become more stringent. Consequently, the number of areas that need to be inspected to improve yield has increased, and the demand for area-based inspection, rather than point measurement or point inspection, is growing even more. Area-based inspection comprehensively inspects the target area and is also called area inspection. In area inspection, multiple inspection points are set on the entire surface or within a specific area of ​​the sample, such as the wafer surface.

[0007] Furthermore, there is a growing demand for systems that use SEM to inspect the entire transfer area (also called a 1-shot) of a single photomask on a wafer with high sensitivity and speed to detect defects in the formation pattern on the photomask. This type of inspection is also called a 1-shot full-surface inspection.

[0008] In area inspections such as 1-shot full-surface inspection, optical adjustments must be made at appropriate locations, similar to conventional point measurement and point inspection. These optical adjustments involve adjusting the beam and electron optics of a charged particle beam apparatus. Patent Document 1 describes an example of a technique for performing such optical adjustments. Patent Document 1 is a technique for inspecting wafers using a charged particle beam apparatus suitable for point measurement and point inspection, such as a CD-SEM (CD: Critical dimension). Patent Document 1 describes how, for each inspection point, addressing points and optical adjustment execution points are automatically selected based on the design layout within the beam shift movement range and shared among the measurement and inspection points.

[0009] On the other hand, prior art examples such as Patent Document 1 allow for the automatic setting of optical adjustment execution locations for each measurement and inspection point. However, in multi-point measurement inspections such as area inspections, it can be difficult to appropriately set the optical adjustment execution locations. In the prior art examples, an optical adjustment execution location is set for each inspection point, and the optical adjustment operation is performed for each execution location.

[0010] Optical adjustment of charged particle beam systems, or in other words, beam adjustment, can sometimes take a relatively long time. Examples of optical adjustment include autofocus. In the case of area inspection, the large number of inspection points can lead to a long inspection time, including optical adjustment time, necessitating measures to reduce inspection time. For example, to comprehensively inspect the entire surface of a single shot, it is necessary to set numerous inspection points within that surface and acquire numerous images for inspection. Furthermore, optical adjustment must be performed each time for the numerous optical adjustment points corresponding to the numerous inspection points. In this case, the numerous optical adjustments take time, resulting in a large amount of effort and time required for the overall inspection.

[0011] Prior art examples such as Patent Document 1 do not describe how to determine and set the locations for optical adjustment during area inspection, taking into account the overall inspection time and throughput.

[0012] Regarding the measurement and inspection of samples using the charged particle beam apparatus described above, particularly for regional inspection, there are two perspectives: one is to determine the appropriate optical adjustment points to ensure and improve inspection sensitivity, and the other is to consider the time required for optical adjustment to ensure and improve inspection throughput. Prior art examples have not adequately considered how to satisfy both of these perspectives, for example, determining and setting suitable or optimal optical adjustment points while considering throughput, and there is room for improvement.

[0013] The purpose of this disclosure is to provide a technology that can maintain or improve throughput while maintaining inspection sensitivity, with respect to technologies such as inspection systems using the charged particle beam apparatus described above. [Means for solving the problem]

[0014] A typical embodiment of this disclosure has the following configuration. The inspection system of the embodiment is an inspection system for performing area inspection of a sample, comprising a charged particle beam apparatus and a computer system connected to or built into the charged particle beam apparatus, wherein the charged particle beam apparatus includes a moving stage on which the sample is mounted, and an adjustment device including an electron source that emits a beam, an electron optical system that adjusts the beam, and a detection system that detects particles emitted from the sample based on the beam, in order to irradiate the sample with a beam which is a charged particle beam, the computer system determines the operating conditions for optical adjustment using the adjustment device with respect to the beam of the charged particle beam apparatus for imaging at multiple inspection points in the inspection area to which the beam that is the target of the area inspection of the sample is irradiated, and when determining the operating conditions for the optical adjustment, the computer system divides the inspection area into divided inspection areas belonging to groups according to pattern classification based on design layout information including information on the pattern formed on the sample, and determines the execution items and execution parameter values ​​of the optical adjustment for each divided inspection area. [Effects of the Invention]

[0015] According to a typical embodiment of the present disclosure, regarding technologies such as an inspection system using the above-described charged particle beam device, throughput can be maintained or improved while maintaining the sensitivity of inspection. Other problems, configurations, effects, etc. other than those described above are shown in the form for carrying out the invention.

Brief Description of the Drawings

[0016] [Figure 1] As the configuration of the inspection system according to Embodiment 1, the configuration of an inspection system including a charged particle beam device and a computer system is shown. [Figure 2] In Embodiment 1, a configuration example of a computer system is shown. [Figure 3] The processing flow by the inspection system according to Embodiment 1 is shown. [Figure 4] In Embodiment 1, based on the design layout information, an explanatory diagram regarding the process of extracting and classifying patterns and dividing the layout is shown. [Figure 5] In Embodiment 1, an explanatory diagram regarding the process of dividing and grouping the inspection area into areas for each pattern classification is shown. [Figure 6] In Embodiment 1, as an example of a GUI screen, a column for displaying the inspection area and the like is shown. [Figure 7] In Embodiment 1, as an example of a GUI screen, a column for displaying the pattern classification result and the like is shown. [Figure 8] In Embodiment 1, as an example of a GUI screen, a column for displaying the inspection area information and the like is shown. [Figure 9] In Embodiment 1, as an example of a GUI screen, a column for displaying the setting information regarding the sensitivity and throughput of inspection is shown. [Figure 10] In Embodiment 1, a setting example of a plurality of inspection points for an inspection area and the like are shown. [Figure 11] In Embodiment 1, it is an explanatory diagram regarding an example of determining the arrangement intervals of the optical adjustment execution position and the necessity determination position based on the wafer height distribution data. [Figure 12]In Embodiment 1, a processing flow related to determining whether optical adjustment is required during inspection is shown. [Figure 13] In Embodiment 1, it is an explanatory diagram of the processing time at the optical adjustment execution location and the determination location of necessity. [Figure 14] In Embodiment 1, it is an explanatory diagram of an arrangement example of the optical adjustment execution location and the determination location of necessity. [Figure 15] In Embodiment 1, it is an explanatory diagram of an example of a movement trajectory. [Figure 16] In a modification of Embodiment 1, it is an explanatory diagram of a setting example such as the optical adjustment execution location. [Figure 17] In the inspection system of Embodiment 2, a processing flow is shown. [Figure 18] In Embodiment 2, an example of a change in optical adjustment when the setting interval is a distance is shown. [Figure 19] In Embodiment 2, an example of a change in optical adjustment when the setting interval is time is shown. [Figure 20] In a modification of Embodiment 2, it is an explanatory diagram of an example of a change in optical adjustment. [Figure 21] In the inspection system of Embodiment 3, it is an explanatory diagram of the processing.

Modes for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same components are generally denoted by the same reference numerals, and repeated descriptions are omitted. In the drawings, the representation of components may not represent the actual position, size, shape, range, etc. in order to facilitate understanding of the invention.

[0018] In explanations, when describing program-based processing, the focus may sometimes be on the program, functions, or processing units. However, the core hardware component is the processor, or a controller, device, computer, or system composed of such a processor. The computer, using its processor, executes processing according to the program read into memory, utilizing resources such as memory and communication interfaces as appropriate. This realizes the specified functions and processing units. The processor is composed of semiconductor devices such as CPUs / MPUs and GPUs. Processing is not limited to software program processing; it can also be implemented using dedicated circuits. FPGAs, ASICs, CPLDs, etc., can be used as dedicated circuits.

[0019] The program may be pre-installed as data on the target computer, or it may be distributed as data to the target computer from the program source. The program source may be a program distribution server on a communication network, or a non-transient computer-readable storage medium, such as a memory card or disk. The program may consist of multiple modules. The computer system may consist of multiple devices. The computer system may consist of a client-server system, a cloud computing system, an IoT system, etc. Various types of data and information are composed of structures such as tables and lists, but are not limited to these. Representations such as identification information, identifiers, IDs, names, and numbers are interchangeable.

[0020] <Solutions, etc.> Traditionally, in regional inspection of a sample, performing optical adjustments before imaging at each inspection point within the inspection area results in a long inspection time. While this allows for high sensitivity, it makes it difficult to increase throughput. An inspection point is a location (for example, a 1 μm x 1 μm area; in other words, an imaging point) that is imaged as part of the field of view along the movement trajectory within the inspection area. Sensitivity refers to the fineness of the image, such as how small a defect can be detected.

[0021] The inspection system of this embodiment performs area inspection rather than point inspection or point measurement. The inspection system of this embodiment uses, for example, a SEM as a charged particle beam device to perform area inspection of a sample, such as a wafer. The inspection system of this embodiment provides functions that enable appropriate optical adjustment of the charged particle beam device, in other words, beam adjustment, such as a function for setting optical adjustment operating conditions.

[0022] The area of ​​the sample subject to inspection (sometimes referred to as the inspection area) can be arbitrarily specified and set by the user. The inspection area can be, for example, the entire sample in one shot, a part of it, or multiple separate areas.

[0023] The inspection system of the embodiment generates an inspection recipe for area inspection. As part of the inspection recipe, the inspection system of the embodiment generates and sets the operating conditions for optical adjustment of the SEM. The operating conditions for optical adjustment are control and setting information for performing optical adjustments related to the beam and electron optics of the SEM.

[0024] The inspection system of this embodiment aims to achieve a balance between the sensitivity of the inspection and the time and throughput of the inspection in relation to regional inspection. In the inspection system of this embodiment, appropriate optical adjustment operating conditions are set for each region of the formation pattern on the sample during regional inspection. This reduces the time and improves throughput while maintaining the sensitivity of the inspection.

[0025] The inspection system of this embodiment performs pattern classification of the inspection area of ​​a sample using design layout information including sample formation pattern information, pattern feature information, manufacturing process information, etc., divides it into groups according to pattern classification, and further divides it into areas (sometimes referred to as segmented inspection areas) according to pattern classification. Each group belongs to one or more segmented inspection areas. Since it is an area inspection, each segmented inspection area in each group is comprehensively imaged and inspected by irradiating the entire area with a beam.

[0026] The inspection system of this embodiment determines and sets suitable or optimal operating conditions for the optical adjustment of the SEM for each segmented inspection area, or in other words, for each group according to the pattern classification. The operating conditions for optical adjustment include the items to be performed and the execution parameter values, as well as the locations where optical adjustment is performed and the locations where necessity is determined.

[0027] The items that can be performed as optical adjustments include autofocus (AF), among others. The parameter values ​​for performing optical adjustments are the parameter values ​​for the item being adjusted; for example, in the case of AF, the parameter values ​​for the objective lens are used as the adjustment device. Optical adjustments are performed for each item using a predetermined adjustment device.

[0028] The inspection system of this embodiment determines and sets the execution parameter values ​​of the execution items for each divided inspection area using at least some of the following: pattern features, manufacturing process information, and settings from past inspections. Pattern features include the presence or absence of a pattern, density, size, shape, and periodicity.

[0029] The optical adjustment execution locations are settings related to the locations where optical adjustment must be performed for multiple inspection points within the segmented inspection area of ​​a region inspection, based on the imaging sequence and movement trajectory. The optical adjustment necessity determination locations are settings related to the locations where it is determined whether or not optical adjustment should be performed for multiple inspection points within the segmented inspection area of ​​a region inspection, based on the imaging sequence and movement trajectory.

[0030] The inspection system of this embodiment determines and arranges the locations for optical adjustment execution and necessity determination for each divided inspection area, within a number, interval, and density that maintains the required inspection sensitivity for the divided inspection area. Unlike conventional area inspections that perform optical adjustment for each inspection point for a large number of inspection points, this inspection system arranges at least one of the optical adjustment execution locations and necessity determination locations on the movement trajectory within the divided inspection area at intervals that take into account the sensitivity and throughput desired by the user.

[0031] The spacing and number of locations for performing the optical adjustments and determining whether they are necessary, as well as the guidelines for inspection sensitivity and throughput used to determine them, may be automatically determined by the inspection system based on a pre-designed system, or they may be set by the user, for example, through a graphical user interface.

[0032] In particular, the computer system of the inspection system of the embodiment generates an inspection recipe that includes the operating conditions for optical adjustment, and causes the SEM to perform the inspection according to the inspection recipe. The SEM performs the inspection according to the inspection recipe, and performs optical adjustment as appropriate during the inspection according to the operating conditions for optical adjustment. At the point where optical adjustment necessity is determined, the necessity is determined based on the captured image for determination, and if the determination result is that adjustment is necessary, optical adjustment is performed.

[0033] The inspection system of this embodiment allows for the setting of different, appropriate optical adjustment operating conditions for each segmented inspection area according to the pattern classification. As a result, when performing area inspection of an inspection area where patterns are mixed, the inspection system of this embodiment can perform optical adjustments that are appropriate for the pattern, compared to conventional technology that performs uniform optical adjustments regardless of the pattern, thereby achieving higher sensitivity inspection.

[0034] Furthermore, the inspection system of this embodiment allows for the setting of optical adjustment execution locations for a smaller number of inspection points in each divided inspection area according to pattern classification, thereby limiting the locations where optical adjustment is performed. As a result, the inspection system of this embodiment can perform optical adjustment in fewer steps compared to conventional technology that performs optical adjustment at each inspection point along the movement trajectory, thereby maintaining or improving the throughput required for inspection including optical adjustment. In addition, the inspection system of this embodiment can set the locations where optical adjustment is performed and the locations where necessity is determined, taking into account the user's desired sensitivity and throughput, thereby optimizing the balance between inspection sensitivity and throughput.

[0035] <Embodiment 1> The inspection system of Embodiment 1 of this disclosure will be explained using Figures 1 to 16. In the inspection system of Embodiment 1 shown in Figure 1, etc., the computer system 200 divides the inspection area of ​​the sample 7 by the SEM 100 into divided inspection areas according to the pattern classification when multiple formation patterns are included within the inspection area. The computer system 200 automatically sets the optical adjustment execution items and execution parameter values ​​for each divided inspection area. Furthermore, the computer system 200 automatically sets the optical adjustment execution locations and necessity determination locations for each divided inspection area at intervals that take into account the sensitivity and throughput of the inspection.

[0036] The computer system 200 generates an inspection recipe that includes the optical adjustment operating conditions described above. The SEM 100 performs area inspection according to this inspection recipe. During inspection, the SEM 100 sequentially references multiple inspection points in the inspection area of ​​the sample 7 in a predetermined imaging order and movement trajectory. If the referenced location corresponds to an optical adjustment execution location, the SEM 100 always performs the specified optical adjustment at that location. As a result of the optical adjustment being performed at that location, the execution parameter values ​​of execution items such as AF are updated to optimal values. In other words, as a result of the optical adjustment, a state is reached where suitable imaging is possible.

[0037] On the other hand, if the reference point corresponds to a point requiring determination, the SEM100 performs a determination at that point. If the determination result is that it is required, optical adjustment is performed at that point; if the determination result is that it is not required, optical adjustment at that point is omitted or skipped.

[0038] [Inspection System] Figure 1 shows the overall structure of the inspection system of Embodiment 1. This inspection system is configured to include a charged particle beam apparatus 100, in this example a SEM 100, as an inspection tool. The SEM 100 consists of a SEM body 101 and a computer system 200, which is a controller connected to the SEM body 101. The SEM body 101 includes parts such as a stage 8 and a column (not shown) equipped with an electron optical system. The computer system 200 controls the operation of the SEM body 101 and performs inspection processing. This inspection system has the function of performing regional inspection of a wafer 7, which is a sample 7.

[0039] Figure 1 mainly shows an example configuration of the SEM100, which is a charged particle beam apparatus 100 that constitutes the inspection system. The SEM100 has a computer system 200, which is a controller, built-in or externally connected. The SEM100 has a mechanism that irradiates the wafer 7 on the stage 8 with a primary electron beam 4 as a charged particle beam 4 for regional inspection. The SEM100 also has a mechanism that controls beams such as secondary electrons 9 and backscattered electrons 9b emitted from the vicinity of the region of the wafer 7 irradiated with the primary electron beam 4, and a mechanism that detects these beams such as secondary electrons 9 and backscattered electrons 9b and converts them into an image. Furthermore, the SEM100 has a mechanism that performs image processing and calculation processing according to the purpose on the image to determine the presence or absence of defects on the wafer 7 and measure dimensions. This function is specifically implemented as a function of the computer system 200.

[0040] The inspection method using the SEM100 includes the step of the SEM100 irradiating the sample 7 on the stage 8 with a charged particle beam 4 as a primary electron beam 4 for regional inspection of the wafer 7, based on control by the computer system 200. The inspection method also includes the step of the SEM100 controlling beams such as secondary electrons 9 and backscattered electrons 9b emitted from the vicinity of the region of the wafer 7 irradiated with the primary electron beam 4, and the step of detecting these beams such as secondary electrons 9 and backscattered electrons 9b and creating an image. Furthermore, the inspection method includes the step of the SEM100, particularly the computer system 200, applying image processing and calculation processing according to the purpose to the image to determine the presence or absence of defects on the wafer 7 and to measure dimensions.

[0041] This inspection system involves a computer system 200 generating an inspection recipe for area inspection. During this process, the computer system 200 generates and sets the operating conditions for optical adjustment. This inspection method includes the step of the computer system 200 generating and setting the operating conditions for optical adjustment.

[0042] The SEM100 includes an electron source 1, extraction electrodes 2, a condenser lens 3, deflectors 5 (5a, 5b), an objective lens 6, a movable stage 8, a secondary electron detector 10, a backscatter electron detector 10b, an astigmatism corrector 20, a secondary electron aligner 21, and other components, which are mounted in a column (not shown). The SEM100 also includes a signal amplifier 11, an A / D converter 12, a signal amplifier 11b, an A / D converter 12b, a main control unit 13, an arithmetic processing unit 14, a memory unit 15, an inspection processing unit 16, a display unit 17, a keyboard 18, a mouse 19, and other components connected to these elements.

[0043] In the example shown in Figure 1, the computer system 200 comprises a computer 201 and a computer 202, to which an input / output device 203 is externally connected. Computer 201 is, in other words, the first computer system, and has a main control unit 13 and an arithmetic processing unit 14. Computer 202 is, in other words, the second computer system, and has a storage unit 15 and a test processing unit 16. Examples of input / output devices include a display unit 17, a keyboard 18, a mouse 19, and other input devices. However, the computer system 200 is not limited to these examples and can be configured with one or more computers, electronic circuit boards, etc.

[0044] The SEM100 applies a voltage to the extraction electrode 2 to emit a primary electron beam 4 from the electron source 1. The emitted primary electron beam 4 is focused onto the wafer 7 by passing through the condenser lens 3, deflector 5a, astigmatism corrector 20, deflector 5b, and objective lens 6, and scans a specific region of the wafer 7. The primary electron beam 4 is also irradiated to any position on the wafer 7 by a stage 8 that is movable in at least the X and Y directions. In the figure, the X and Y directions are two orthogonal directions that constitute the horizontal plane, and the Z direction is perpendicular to the X and Y directions. The stage 8 may be a stage (in other words, a sample stage) that can move in the Z direction and rotate around each axis.

[0045] A deflector 5a is positioned above the astigmatism corrector 20, and a deflector 5b is positioned below it. The astigmatism of the primary electron beam 4 is corrected by the astigmatism corrector 20. The primary electron beam 4 is also adjusted by the deflectors 5(5a,5b) to pass through the axis center. The deflectors 5(5a,5b) adjust the optical axis of the primary electron beam 4.

[0046] When the primary electron beam 4 is irradiated onto the surface of the wafer 7, secondary electrons 9 and backscattered electrons (BSE) 9b are emitted from near the irradiation point. The emitted secondary electrons 9 are incident on the secondary electron detector 10 via the secondary electron aligner 21. The emitted backscattered electrons 9b are incident on the backscattered electron detector 10b. The secondary electrons 9 are orbit-adjusted by the secondary electron aligner 21 so that they are incident on the secondary electron detector 10. The secondary electron detector 10 detects the incident secondary electrons 9 as signal electrons. The backscattered electron detector 10b detects the incident backscattered electrons 9b as signal electrons. The secondary electron detector 10 is a detector that detects secondary electrons 9, and the backscattered electron detector 10b is a detector that detects backscattered electrons.

[0047] A signal amplifier 11 and an A / D converter 12 are connected downstream of the secondary electron detector 10. A signal amplifier 11b and an A / D converter 12b are connected downstream of the backscattered electron detector 10b. The signal amplifier 11 amplifies the signal electrons from the secondary electron detector 10. The A / D converter 12 converts the amplified analog signal from the signal amplifier 11 into a digital signal and outputs it as an image. The image output from the A / D converter 12 is input to the computer 201. The signal amplifier 11b amplifies the signal electrons from the backscattered electron detector 10b. The A / D converter 12b converts the amplified analog signal from the signal amplifier 11b into a digital signal and outputs it as an image. The image output from the A / D converter 12b is input to the computer 201.

[0048] In computer 201, the arithmetic processing unit 14, connected to the main control unit 13, performs image processing and arithmetic processing on the input image according to the settings and purpose. The images and data obtained as a result of these processes are stored in the storage unit 15 of computer 202.

[0049] Furthermore, in the computer 202, the inspection processing unit 16 connected to the memory unit 15 performs image processing and calculation processing on the images stored in the memory unit 15 according to the purpose, thereby performing predetermined inspections such as searching for and determining defects on the wafer 7 and measuring the dimensions of the formed pattern. Note that "defect" is a general term that includes foreign objects and defects that differ significantly from the standard. Also, "inspection" is a general term that includes imaging, observation, measurement, inspection, evaluation, and analysis.

[0050] Computer 201 implements the main control unit 13 and the arithmetic processing unit 14 based on program processing by the processor. Computer 202 implements the test processing unit 15 based on program processing by the processor. However, each part, such as the arithmetic processing unit 14 and the test processing unit 15, may be implemented using dedicated circuits or the like. The storage unit 15 is configured using, for example, a non-volatile memory device. However, other external memory devices or server devices may be used for the computer system 200.

[0051] Furthermore, region inspection may involve handling a large number of images. In such cases, the memory capacity required by the memory unit 15 may be large. To address this, parallel processing may be introduced in the inspection processing unit 16. That is, the inspection processing unit 16 may perform inspection processing on multiple images in parallel. This enables high-speed processing.

[0052] Furthermore, the results of defect inspection or dimensional measurement performed by the inspection processing unit 16 are stored in the storage unit 15 and, if necessary, displayed on the screen of the display unit 17. Users, such as inspectors, use this inspection system to perform inspection work by operating the computer system 200 and SEM 100 through the input / output device 203.

[0053] The user can set the operating conditions of the SEM100 by operating the keyboard 18, mouse 19, etc., based on the graphical user interface (GUI) displayed on the screen of the display unit 17. The main control unit 13 of the computer 201 controls the operation of each component of the SEM100 (including electron sources 1 to stage 8 in Figure 1) based on the operating conditions set in advance by the user.

[0054] [Optical adjustment device] In the inspection system of Embodiment 1, the computer system 200 performs optical adjustment of the SEM 100. In other words, the SEM 100 performs optical adjustment based on control by the computer system 200. During this optical adjustment, the computer system 200 controls the optical adjustment devices provided in the SEM 100 to perform the adjustment. A corresponding optical adjustment device is used for each optical adjustment item. The optical adjustment device is a device that includes an electron source 1 that emits a beam, which is a charged particle beam 4, onto the sample 7, an electron optical system that adjusts the beam, and a detection system that detects particles emitted from the sample 7 based on the beam. Specific examples of the optical adjustment device include the electron source 1, extraction electrode 2, condenser lens 3, deflector 5 (5a, 5b), objective lens 6, movable stage 8, secondary electron detector 10, backscattered electron detector 10b, astigmatism corrector 20, secondary electron aligner 21, etc., as shown in Figure 1.

[0055] In Embodiment 1, the optical adjustment refers to various adjustments related to the conditions for irradiating the sample 7 with the charged particle beam 4 by the charged particle beam apparatus 100, which is the SEM 100, and the conditions for detecting secondary electrons 9 and backscattered electrons 9b. This optical adjustment broadly refers to the adjustment of conditions that affect the imaging of the sample 7 and the resulting image. For example, the reference voltage applied to the stage 8 is also adjusted so that a voltage is formed on the sample 7 on the stage 8 in conjunction with the irradiation of the charged particle beam 4. Such a voltage is also included as one of the parameters of the optical adjustment. In addition, secondary electrons 9 and the like are detected from the surface of the sample 7 by the secondary electron detector 10 of the SEM 100, and an image is captured based on the detection signal. The settings of circuits related to such detection and the settings of image processing for the image after detection are also included as one of the parameters of the optical adjustment.

[0056] In other words, the optical adjustment device is a general term for the hardware and software used to perform optical adjustment in Embodiment 1, etc. The optical adjustment device also includes a drive system that applies voltage to the stage 8, a secondary electron detector 10, a signal amplifier 11, an A / D converter 12, and circuits for image processing. The details of optical adjustment and the optical adjustment device are not limited to the examples described in Embodiment 1, etc., and may vary depending on the implementation of the charged particle beam apparatus.

[0057] [Computer System] Figure 2 shows an example configuration and data information for the computer system 200. In the example in Figure 2, computer 201, computer 202, and SEM 100 are connected to the LAN and can communicate with each other. For example, SEM 100 and computer 201 may be directly connected, or computer 201 and computer 202 may be directly connected.

[0058] Computer 201 includes a processor 211, memory 212, communication interface device 213, input / output interface device 214, etc., all of which are connected to a bus. Computer 201 implements the main control unit 13 and arithmetic processing unit 14 as, for example, execution modules by executing processing according to a control program using the processor 211. Memory 212 stores pre-set information, various information entered by the user, and various information generated by computer 201. Communication interface device 213 implements a communication interface for communicating with SEM 100 and computer 202 via LAN. The input / output interface device 214 is connected to the display unit 17 and keyboard 18 shown in Figure 1.

[0059] In this example, memory 212 contains design layout information 231, pattern classification and determination information 232, manufacturing process information 233, inspection sensitivity information 234, throughput information 235, inspection setting information 236, optical adjustment setting information 237, inspection recipe information 238, etc. This data information is set or generated as needed.

[0060] Computer 202 includes a processor 221, memory 222, communication interface device 223, input / output interface device 224, etc., which are connected to a bus. Computer 202 implements the inspection processing unit 16, for example, as an executable module, by executing processing according to a control program using the processor 221. The storage unit 15 is implemented, for example, as a storage area of ​​memory 222 managed by the processor 221. The storage unit 15 may also be implemented as a storage area of ​​an external storage device connected to computer 202. In this example, the storage unit 15, which is memory 222, stores image data 251 and inspection result data 252, etc.

[0061] The design layout information 231 is design data that includes information that allows us to understand the layout of the pattern formed on the surface of the wafer 7, which is the sample 7.

[0062] The pattern classification judgment information 232 is judgment information used by this inspection system when performing pattern classification, or in other words, division into grouping and partitioning inspection areas, as described later, and includes, for example, information for determining pattern features.

[0063] Manufacturing process information 233 is information regarding the manufacturing process of sample 7 and the semiconductor device.

[0064] The inspection sensitivity information 234 is setting information about the desired inspection sensitivity that the user wants to ensure for area inspection, and an example of this is the sensitivity threshold for defect inspection.

[0065] Throughput information 235 is setting information about the desired throughput or time that the user wants to ensure for area inspection, for example, a threshold for the time required for inspection. Inspection sensitivity information 234 and throughput information 235 may be information such as degree or level, or information for setting the balance between the two.

[0066] The inspection setting information 236 includes setting information for the target sample 7 and inspection area (for example, the entire 1-shot area, or an area arbitrarily specified by the user) related to area inspection, as well as setting information for optical conditions.

[0067] The optical adjustment setting information 237 is setting information regarding the operating conditions of optical adjustment and is unique information generated by this inspection system. The optical adjustment setting information 237 includes information on the execution items and execution parameter values ​​described later, as well as information on the optical adjustment execution locations and the locations where necessity / determination is determined.

[0068] The inspection recipe information 238 is information generated by this inspection system, including optical adjustment setting information 237, that is a recipe for the SEM 100 to perform area inspection; in other words, it is inspection instruction information and inspection control information. The inspection recipe information 238 also includes information such as imaging conditions, optical conditions, imaging order, and movement trajectory.

[0069] Furthermore, other devices may be connected to the LAN in Figure 2. These other devices may include, for example, a user's client terminal, an external defect inspection device, or a manufacturing execution system (MES). The computer system 200 may communicate with these external devices to input and output necessary data and information. The computer system 200 may also function as a server, forming a client-server system with the user's client terminal. In this case, the server computer system 200 handles the main processing, while the user's client terminal handles the GUI. The computer system 200 generates GUI information and data information, for example, in the form of a web page, and sends it to the user's client terminal. The user can view the GUI and data information displayed on the client terminal's screen and input instructions and settings as needed. The client terminal sends these instructions to the computer system 200. The computer system 200 processes the instructions and sends the GUI information, including the processing results, to the client terminal.

[0070] [Overview of the testing system] The inspection system of Embodiment 1 has at least a function for setting the operating conditions for optical adjustment of the SEM100. The inspection method has steps corresponding to this function. The outline of the processing of this inspection system is as follows.

[0071] This inspection system inputs, references, and acquires information such as design layout information 231, pattern classification and determination information 232, manufacturing process information 233, inspection sensitivity information 234, and throughput information 235 for the target sample 7, such as wafer 7, based on user operations. Based on user operations, this inspection system sets one or more inspection areas (inspection setting information 236) that are the areas of the sample 7 to be inspected.

[0072] This inspection system classifies the formation patterns within the layout of a sample 7 area (e.g., the entire 1-shot area) or a designated inspection area based on this information. Pattern features and manufacturing process information are referenced during this pattern classification. Pattern features include information such as the presence or absence of a pattern, density, size, shape, and periodicity. If the inspection area contains multiple patterns of different classifications, the inspection system divides the inspection area into multiple areas, one for each pattern. These divided inspection areas are referred to as divided inspection areas. The inspection system then divides these divided inspection areas into groups corresponding to the pattern classifications. That is, each divided inspection area belongs to a group corresponding to a specific pattern classification.

[0073] This inspection system determines and sets the optical adjustment execution items and execution parameter values ​​for each group of inspection areas, and determines and sets the optical adjustment execution locations and the locations where necessity or non-necessity judgments are made for each divided inspection area. When determining the optical adjustment execution items and execution parameter values, at least some of the pattern features, manufacturing process information, and past inspection setting information are used.

[0074] This inspection system determines, for each group of optical adjustment execution items and execution parameter values ​​determined above, at least one of the optical adjustment execution locations and optical adjustment necessity determination locations within the divided inspection area. The inspection system determines the type and presence of these locations, as well as their spacing and number, taking into account the user's desired inspection sensitivity (inspection sensitivity information 234) and throughput (throughput information 235). The inspection system determines the placement of these locations in a number and spacing that maintains the required inspection sensitivity in each divided inspection area.

[0075] This inspection system generates and stores an inspection recipe (inspection recipe information 238) that includes the optical adjustment operating conditions (optical adjustment setting information 237) including the execution items and execution locations determined above.

[0076] This inspection system performs region inspection of sample 7 by controlling the SEM100 based on the inspection recipe described above. In region inspection, an image is captured for each inspection point within the divided inspection region (image data 251), and inspection processing is performed using these images to generate and save inspection results (inspection result data 252). When performing region inspection, this inspection system sequentially references multiple divided inspection regions as inspection regions according to the imaging order and movement trajectory specified in the inspection recipe, and sequentially references multiple inspection points within each divided inspection region. If the current reference location (corresponding inspection point or imaging field) corresponds to an optical adjustment execution location, this inspection system performs the specified optical adjustment. If the reference location corresponds to an optical adjustment necessity determination location, this inspection system determines whether optical adjustment is necessary, and if the determination result is necessary, optical adjustment is performed; otherwise, optical adjustment is not performed.

[0077] [Processing flow] Figure 3 shows the processing flow by the computer system 200 in the inspection system of Embodiment 1, and has steps S101 to S112. The example processing flow in Figure 3 is characterized by including a process to set divided inspection areas based on pattern classification and to automatically set the operating conditions for optical adjustment of the SEM 100 for each divided inspection area. Furthermore, the example processing flow in Figure 3 shows a case where pattern classification is performed before the user sets the inspection area, and the user sets the inspection area for the area of ​​the pattern classification result.

[0078] In step S101, the computer 201 of the computer system 200 (particularly the arithmetic processing unit 14; the same applies hereafter) inputs the information necessary for processing related to area inspection. The user inputs design layout information 231, pattern classification and determination information 232, manufacturing process information 233, inspection sensitivity information 234, throughput information 235, etc. (Figure 2) for the target sample 7 on the GUI screen of the input / output device 203.

[0079] In this case, the user may input detailed information, or the computer may instruct the computer to load pre-configured information or external information. The computer may also automatically input the necessary information, not limited to user input. For example, the computer may refer to design layout information 231 or manufacturing process information 232 from an external MES (Manufacturing Execution System). Furthermore, if the inspection area of ​​sample 7 is pre-configured as inspection setting information 236, the computer may load that inspection setting information 236. Additionally, if the inspection setting information 236 includes settings for the imaging conditions or optical conditions of the SEM 100, that information may also be loaded. Some of the above input information may also be entered in later steps.

[0080] In step S102, the computer 201 classifies the formed pattern for a region of the wafer 7, which is the sample 7, for example, the entire 1-shot area, based on the design layout information 231 and the pattern classification determination information 232, etc.

[0081] In step S103, the computer 201 divides the area (in other words, the layout) of sample 7 into areas for each pattern classification, based on the results of the pattern classification in step S102. Here, the divided areas are referred to as divided areas (or pattern areas).

[0082] In step S104, the computer 201 displays the divided region resulting from step S103 on the GUI screen provided by the input / output device 203.

[0083] In step S105, the user checks the divided areas on the GUI screen. On the GUI screen, the user sets one or more inspection areas for the divided areas within the sample 7 region. The inspection area here is the desired area that the user wants to inspect. For example, the user may select a divided area to be used as an inspection area, or they may specify any area within the sample 7 region as an inspection area.

[0084] In step S105, the user sets the imaging field size per inspection point on the GUI screen described above. The imaging field size per inspection point is set to, for example, 1 μm × 1 μm. If there are already set imaging field sizes or other settings as imaging conditions, those settings may be applied as is. If the imaging field size or other settings are defined as fixed values ​​in the design of the SEM100, those values ​​will be applied. Also, the inspection points have not yet been determined at this point.

[0085] In step S106, the computer 201 checks whether there is a test area among the one or more test areas set in step S105 that contains a different pattern. If there is (Y), proceed to step S107; otherwise, proceed to step S108.

[0086] In step S107, the computer 201 divides one or more inspection areas set by the user into areas for each pattern classification, based on the divided areas (in other words, pattern classification, layout division results) from step S103. Here, the divided results are referred to as divided inspection areas. For example, if one inspection area specified by the user contains divided areas for two patterns, it will result in two divided inspection areas, one for each pattern.

[0087] In step S108, the computer 201 divides one or more inspection areas set by the user into one or more groups according to the pattern classification. In the flow from step S106 to S108, for example, if there are only areas with the same pattern within one inspection area, then one inspection area will belong to one group. In the flow from step S107 to S108, for example, if there are multiple divided inspection areas with different patterns, then one or more divided inspection areas will belong to each pattern group.

[0088] In step S109, the computer 201 determines and sets the optical adjustment execution items and execution parameter values ​​for each group of inspection areas set up to step S108. Details will be described later.

[0089] In step S110, the computer 201 determines and sets the locations for optical adjustment execution and the locations for determining whether or not it is necessary, for each group of inspection areas and each subdivided inspection area within a group. Details will be described later.

[0090] In either step S109 or S110 described above, the operating conditions corresponding to the pattern classification are determined.

[0091] In step S111, the computer 201 generates an inspection recipe that includes the operating conditions for optical adjustments generated up to step S110, as well as setting information such as other imaging conditions and optical conditions, and saves it in the database (inspection recipe information 238 in Figure 2).

[0092] In step S112, the inspection processing unit 16 of the computer system 200, particularly computer 201, controls the SEM 100 according to the inspection recipe described above, performs the inspection using the SEM 100, and saves the inspection results (inspection result data 252 in Figure 2). The execution of the inspection is started, for example, based on user input. During the execution of the inspection using the SEM 100, specified optical adjustments are performed at appropriate locations and timings, as described above.

[0093] Furthermore, the process flow example described above is not the only possible configuration. For example, a user could set an inspection area, and then perform pattern classification on that inspection area to set up multiple subdivided inspection areas.

[0094] [Processing flow details] The following sections will explain the details and specific examples of each step in the processing flow shown in Figure 3.

[0095] [S101: Information Input] The user inputs design layout information 231 for wafer 7 via a GUI screen. Design layout information 231 may include layout data in a known format such as GDS or OASIS, created during the design of wafer 7. Alternatively, design layout information 231 may include wide-field images in which the pattern layout can be recognized, captured using an optical microscope or charged particle beam apparatus (such as the SEM100 in Figure 1, or other types of apparatus). Design layout information 231 may consist of some or all of this data or images.

[0096] Furthermore, even if data in formats such as GDS or OASIS is not available, if the user is aware of the pattern layout of sample 7, the user may create a file or similar document representing that pattern layout and input it as design layout information 231.

[0097] [S102: Pattern classification, S103: Region segmentation] Figure 4 is an explanatory diagram of the process for steps S102 and S103, in which patterns are extracted and classified based on design layout information 231, etc., and the layout of sample 7 is divided. In step S102, as shown in the example in Figure 4, the computer 201 extracts and classifies the patterns included in the layout of sample 7 based on design layout information 231, etc., and divides the layout into regions for each pattern.

[0098] The input region 401 is an example of the region of sample 7, for example, containing six rectangular regions within the base region, each containing a different pattern layout. The computer 201 extracts the pattern 402 from the input region 401 using the pattern features 400. The pattern features 400 represent information such as the presence or absence of a pattern, density, size, shape, and periodicity. The pattern features 400 correspond to a part of the pattern classification information 232 in Figure 2. The extracted pattern 402 has, for example, six different patterns.

[0099] Pattern classification result 403 is the result of classifying pattern 402, and in this example, it is classified into three types of patterns (in other words, pattern classifications) shown as A, B, and C. For example, pattern classification A is a vertical line pattern, pattern classification B is a horizontal line pattern, and pattern classification C is a non-line pattern.

[0100] The layout division result 404 is the result of dividing the layout of the input area 401 into divided areas, which are areas for each pattern classification, based on the pattern classification result 403. In the layout division result 404, labels representing the pattern classification are assigned to the divided areas for each pattern classification in the layout of the input area 401. The input area 401 is divided into divided areas for three types of pattern classifications, A to C. The computer 201 assigns identification labels (e.g., A, B, C) to these pattern divided areas based on the pattern classification result 403. In the layout division result 404 of this example, the line pattern areas for pattern classifications A and B are each divided into, for example, four areas, but the base area and the two areas on the left are combined into a single divided area for the same pattern classification C.

[0101] One method for extracting patterns in step S102 is to use the 400 feature quantities of the pattern as an index value and extract patterns based on a threshold value set for that index value. In addition, in the case of design layout data such as GDS and OASIS, each pattern may be assigned a name or other information. Therefore, a method of extracting patterns based on that information can also be applied.

[0102] A pattern classification method for classifying the extracted patterns can be a clustering method that uses the 400 feature quantities of the pattern as index values ​​and classifies the patterns based on thresholds set for these index values. Alternatively, the thresholds set during the pattern extraction stage can be used directly as classification frames, or separate thresholds can be set if similar patterns are to be grouped into a single classification frame to allow for the simultaneous setting of the optical adjustment operating conditions described later. Furthermore, it is also possible to use the names assigned to each pattern within design layout data such as GDS or OASIS as classification frames.

[0103] The threshold values ​​set for the pattern features may be obtained by reading default values ​​stored in a database beforehand (pattern classification information 232 in Figure 2), or by using threshold values ​​arbitrarily set by the user. For example, if the user wants to inspect wafer 7 focusing on line patterns as a specific pattern, then indicators such as features and threshold values ​​for determining that specific pattern, the line pattern, are used. These indicators may be one or more pieces of information, such as the aspect ratio, pattern shape and periodicity including the occurrence rate of pattern edges in each direction, and pattern size, and can be set by the user on the GUI screen.

[0104] In the case of a vertical line pattern (Figure 10, described later), for example, if the pattern shape is a rectangle (a rectangle with one line), the XY aspect ratio is above a threshold, the proportion of pattern edges appearing in any direction is only in the X direction, and there is periodicity in the X direction, then it can be determined to be a vertical line pattern. The X direction is the horizontal direction, and the Y direction is the vertical direction. Also, if the XY aspect ratio is below a threshold, the proportion of pattern edges appearing in any direction is only in the Y direction, and there is periodicity only in the Y direction, then it can be determined to be a horizontal line pattern. Regions where patterns satisfying these conditions are formed can be classified as vertical line patterns (Pattern Classification A) and horizontal line patterns (Pattern Classification B), as shown in the example in Figure 4, and all others can be classified as Pattern Classification C. Furthermore, methods for extracting features using image processing autocorrelation can also be applied.

[0105] Furthermore, settings such as thresholds for pattern classification are stored in a database (pattern classification information 232 in Figure 2). This allows users to retrieve and reuse the information from the database when inspecting similar line patterns using the SEM100, thus saving time on configuration. Additionally, even users with little or no experience with SEM can easily classify patterns in a layout by recalling the saved settings.

[0106] [S104: Display divided area] As a result of steps S102 and S103 described above, divided regions for each pattern classification (for example, layout division result 404 in Figure 4) are generated. In step S104, the computer 201 displays the layout division result 404, etc., on the GUI screen. Figures 6 to 9 show examples of GUI screens.

[0107] Figure 6 shows an example of a GUI screen, specifically a section for displaying user-defined inspection areas on the layout division results. Figure 7 shows a section for displaying pattern classification results within the layout. Figure 8 shows sections for displaying inspection area information, selected inspection area information, and test inspections. Figure 9 shows a section for setting information related to inspection sensitivity and throughput. Note that each GUI screen example, such as those in Figures 6 to 9, may be displayed in parallel on one large screen or individually.

[0108] First, the GUI screen example in Figure 6 displays the contents of the layout division result 404, which is based on the layout division result 404 as shown in Figure 4, or in other words, the division area for each pattern classification.

[0109] [S105: Setting the inspection area] In step S105, the user sets one or more inspection areas on the GUI screen. The user sets one or more desired inspection areas 500 while checking the layout division results 404, etc., on a screen like the one shown in Figure 6.

[0110] Figure 5 shows an explanatory diagram of the process in which, with respect to the layout division result 404 (Figure 4) from step S103, the user sets an inspection area 500 in step S105, and then in steps S107 and S108, the inspection area 500 is divided into areas (divided inspection areas) according to pattern classification and grouped.

[0111] Furthermore, Figure 6 shows an example where the user sets a desired inspection area 500 on top of the contents of the layout division result 404 as shown in Figures 4 and 5, and displays that inspection area 500 as a frame. In this example, the user sets a single rectangular inspection area 500 that spans multiple division areas.

[0112] One way to set the inspection area in step S105 is for the user to input coordinates. Another effective method is for the user to set the inspection area 500 by clicking or dragging on the layout division result 404 as shown in Figure 6.

[0113] In the layout division results display in Figure 6, for example, each divided area classified by pattern is enclosed by a closed curve frame and color-coded to make the boundaries clear and stand out. This allows users to use this display result as a guideline to more easily set the desired inspection area. Alternatively, users could be allowed to select a divided area by clicking or other means and set that divided area as one of the inspection areas. Such a UI is intuitive, easy to use, and effective.

[0114] In this example, the inspection area 500 contains three types of pattern classification areas, indicated by labels A, B, and C, similar to Figures 4 and 5, resulting in a total of five divided areas. In this example, five labels, No. 1, No. 2, No. 3, No. 4, and No. 5, are assigned as labels (in other words, identification information) separate from the pattern classification labels, in order to distinguish each of the five individual areas. The labels and identification information may be displayed as text or marks within the corresponding areas, as in this example, or as a display with a leader line, as in No. 5.

[0115] The GUI screen shown in Figure 6 displays the design layout of wafer 7, the user-defined inspection area 500, the segmented inspection area set by computer 201, inspection points within the segmented inspection area, and the locations for optical adjustment execution and necessity determination described later. The user can select what to display on the screen using the GUI. Figure 6 also shows examples of settings for optical adjustment execution locations described later, but these are set in later steps. This inspection system may also plot and display the optical adjustment execution locations and necessity determination locations described later on the inspection area 500. For example, within the segmented inspection area indicated by label A, No. 1, multiple (3 x 4) optical adjustment execution locations are displayed, indicated by white dots.

[0116] In the GUI screen example in Figure 7, information regarding the pattern classification results within the layout is displayed. In this example, the information regarding the pattern classification results includes the number and labels of classification boxes (in other words, pattern classifications or groups), the pattern classification threshold for each classification box, and a breakdown list of the patterns included in each classification box. Tabs are automatically created according to the number of classification boxes. A new classification box can be created by pressing the "+" tab button. In this example, information is displayed in separate tabs for each pattern classification (e.g., A to C). In the tab for a particular pattern classification (e.g., A), there are fields from top to bottom: "Pattern Classification Threshold," "Pattern List," and "Optical Adjustment."

[0117] In the "Pattern Classification Threshold" section, you can set and check the threshold for each pattern feature (400 pattern features in Figure 4) required to be classified into the group (e.g., A) in the classification box of the tab.

[0118] The "Pattern List" section displays a list of patterns categorized into groups within the tab's classification box, along with an image and information (such as shape, periodicity, aspect ratio, size, etc.) for each pattern.

[0119] In the "Optical Adjustment" section, a list of candidate optical adjustment items is displayed for areas containing patterns categorized within the group of classification boxes in the relevant tab. For each item, the necessity and execution parameter values ​​can be checked and set. The necessity and execution parameter values ​​are displayed as determined automatically by computer 201, and the user can also check and change them. In this example, AF, AST, ABCC, etc., described later, are displayed as optical adjustment items.

[0120] Furthermore, Figure 7 shows examples of buttons for user-selectable instructions, such as "Set Inspection Area," "Set Group Splitting / Merging," and "Display Grouping Results as a Map." When the "Set Inspection Area" button is pressed, a dedicated GUI (e.g., a pop-up) for setting inspection areas opens, allowing the user to set the inspection areas using that GUI. The result of the setting is displayed as inspection area 500, as shown in Figure 6. When the "Set Group Splitting / Merging" button is operated, a dedicated GUI (e.g., a pop-up) opens, allowing the user to further subdivide or merge the groups based on the results of the pattern classification (e.g., A-C) automatically performed by computer 201. The "Display Grouping Results as a Map" setting allows the user to configure whether to display the grouping results of the inspection areas (e.g., Figure 5) as a map, depending on whether the check mark is turned on or off.

[0121] After visually confirming the layout division results on the screen in Figure 6 and the pattern classification results in Figure 7, the user can manually make changes to the inspection area and pattern classification groups as needed. For example, the user can change the pattern classification threshold on the screen in Figure 7 and perform pattern classification again. The user can also use "Group Splitting / Merging" to, for example, distribute some of the patterns included in one classification frame to another classification frame. In this way, by allowing user changes based on the automatic processing results from computer 201, the pattern classification can be optimized. In this case, the operating conditions for optical adjustment, which will be described later, can be set in more detail.

[0122] In the example GUI screen in Figure 8, information such as "Inspection Area Information," "Selected Inspection Area Information," and "Test Inspection" is displayed. In the "Inspection Area Information" section, information for each individual segmented inspection area in inspection area 500 in Figure 6 is displayed. In the "Inspection Area Information" section, each area has information such as number (No.), group to which it belongs (in other words, pattern classification), coordinates, area, inspection necessity, inspection time, optical adjustment execution interval, and optical adjustment necessity determination interval.

[0123] The "Inspection Requirement" status is automatically checked by computer 201 to indicate "Required," and the user can uncheck it to indicate "Not Required" if they determine that inspection is not necessary. The "Inspection Time" displays the inspection time estimated by computer 201 for the inspection area in question. This estimated inspection time can be calculated, for example, based on past performance data of similar inspections. The "Optical Adjustment Execution Interval" displays the interval (described later) of the optical adjustment execution points determined by computer 201 for each execution item such as AF, and the user can also change this. For example, the display "AF:1" indicates that the interval of the optical adjustment execution points is set by one of the inspection point intervals, based on the inspection point interval. Similarly, the "Optical Adjustment Requirement Determination Interval" displays the interval of the optical adjustment requirement determination points for each execution item, and the user can also change this.

[0124] The "Selected Inspection Area Information" section displays information about the inspection area (divided inspection area) selected by the user from the "Inspection Area Information" section. This includes a list of multiple inspection points within that area and information about each inspection point. For example, if row No. 4 of the inspection area is selected, as shown in the shaded area, the information for that selected inspection area is displayed in this section. The "Selected Inspection Area Information" section contains information such as the number of the selected inspection area, inspection point number, coordinates, inspection requirement, inspection time, optical adjustment execution, optical adjustment requirement determination, and individual settings / details.

[0125] "Inspection Requirement" indicates whether inspection is required for the inspection point in question. The computer 201 automatically determines this requirement, and the user can change it. "Inspection Time" displays the inspection time estimated by the computer 201 for the inspection point in question. "Optical Adjustment Execution" displays whether each optical adjustment execution item is executed, as determined by the computer 201, and the user can change it. "Optical Adjustment Requirement Determination" displays whether each optical adjustment execution item is deemed necessary, as determined by the computer 201, and the user can change it. "Individual Settings / Details" is checked when the user wants to make individual settings for the inspection point in question, and details can be set in a separate GUI.

[0126] The "Test Inspection" section includes start and stop buttons to execute a test inspection to verify whether a normal inspection can be performed under the set imaging and optical conditions. When the start button is pressed, a test inspection is initiated for a user-defined area of ​​sample 7 under the set imaging and optical conditions. The stop button ends the test inspection. The user can view and confirm the test inspection results on the screen and readjust the imaging and optical conditions based on the results.

[0127] Figure 9 shows another example of a GUI screen where the user can set information regarding the sensitivity and throughput of the test. In the example screen in Figure 9, in the "Sensitivity and Throughput Settings" section, the user can set target values ​​for the desired sensitivity and throughput for each group based on pattern classification for the test area of ​​the target sample. In this example, the aforementioned groups A, B, and C are displayed, and the parentheses in the group indicate the segmented test area to which it belongs.

[0128] This example shows a case where the priority and balance between sensitivity and throughput (which can also be expressed as time) can be set for each group using a slider bar. For example, a setting further to the left on the slider bar represents a priority on sensitivity, and a setting further to the right represents a priority on throughput. Computer 201 determines the optical adjustment operation conditions for each segmented inspection area of ​​each group, as described below, according to the target values ​​for sensitivity and throughput set by the user on this screen. For example, if a group prioritizes sensitivity, the intervals between optical adjustment execution points will be shorter and the number of points will be higher, depending on the magnitude of the target value for sensitivity. If necessity / non-necessity judgment points are included, the intervals between necessity / non-necessity judgment points will also be shorter and the number of points will be higher. Similarly, if throughput is prioritized, the intervals between optical adjustment execution points will be longer and the number of points will be lower, depending on the magnitude of the target value for throughput. If necessity / non-necessity judgment points are included, the intervals between necessity / non-necessity judgment points will also be longer and the number of points will be lower.

[0129] This example screen is not limited to this one; it may be possible to set target values ​​for each sample or for each inspection area collectively, or to set target values ​​individually for each divided inspection area. Furthermore, target values ​​for sensitivity and throughput may be set for each optical adjustment item, such as AF.

[0130] Other GUI screen examples include allowing the user to specify in detail the spacing and number of optical adjustment execution locations and locations for determining necessity. Alternatively, several modes could be predefined for the spacing and number of optical adjustment execution locations and locations for determining necessity, or for guidelines on inspection sensitivity and throughput, allowing the user to select and use one of these modes. Figure 9 shows an example of such a mode selection in the "Optical Adjustment Modes" section at the bottom of the screen. This section offers several modes, including sensitivity priority mode, balanced mode, and throughput priority mode. Each mode specifies whether optical adjustment execution locations and locations for determining necessity are present, and the spacing of these locations is internally configured, allowing the user to view the details.

[0131] [S106~S108] Return to Figure 3, etc. Specific examples of steps S106 to S108 are shown in Figure 5. The computer 201 assigns labels (e.g., A, B, C) to each pattern classification based on the pattern classifications contained in the inspection area 500 (Figure 6) set by the user, divides the inspection area 500 into separate inspection areas for each pattern classification, and separates them into groups for each pattern classification. If, for example, only one pattern classification is contained within one inspection area, the process proceeds to step S108 in Figure 3, and that single inspection area is assigned a label representing that single pattern classification and belongs to one group.

[0132] On the other hand, as shown in the example in Figure 5, a user-defined inspection area 500 may contain multiple different pattern classifications belonging to separate classification boxes. In this case, the inspection area 500 cannot be grouped into a single area and must be divided and reconfigured into areas for each pattern classification. Manually reconfiguring this becomes increasingly time-consuming as the pattern layout becomes more complex. Therefore, the computer 201 of this inspection system performs this reconfiguration automatically.

[0133] In other words, if the computer 201 proceeds to step S107 in Figure 3, it divides the user-specified inspection area 500 into separate inspection areas for each pattern classification based on the layout division result 404 (Figure 4). In the example in Figure 5, the inspection area 500 is divided into separate inspection areas 511 to 515. Then, in step S108, the computer 201 divides the multiple separate inspection areas into multiple groups and assigns a label representing the group and a label (identification information) representing the individual areas to each separate inspection area. In the example in Figure 5, it is divided into five separate inspection areas 511 to 515 based on pattern classifications A, B, and C, and these separate inspection areas are divided into three groups of labels A, B, and C corresponding to pattern classifications A, B, and C. For example, group 501 is group A, which corresponds to pattern classification A, and includes two separate inspection areas 511 and 512.

[0134] [Inspection points and imaging field of view] In step S105 described above, the imaging field size per inspection point is set as part of the imaging conditions. Based on the set imaging field size, the computer 201 of this inspection system places inspection points within each segmented inspection area in step S108, etc., and determines the imaging field for each inspection point. Since it is a region inspection, multiple inspection points are placed at appropriate intervals within the segmented inspection area so that the entire segmented inspection area can be imaged.

[0135] Figure 10 is a supplementary diagram illustrating an example where multiple inspection points are arranged within a segmented inspection area and an imaging field of view is set. In this example, inspection points p1 to p18 are set within the segmented inspection area 511 of group A in Figure 5. The inspection points are shown as white circles. For example, inspection point p1 is represented by position coordinates (x1, y1), and a rectangular imaging field of view 1001 (for example, an area of ​​1 μm × 1 μm) is set using this inspection point as the imaging point. That is, an image can be acquired within such an imaging field of view 1001. In this example, the inspection point is the center point of the imaging field of view, but this is not limited to this. Similarly, each inspection point has an imaging field of view of the same size, and these imaging fields of view cover the entire segmented inspection area 511.

[0136] In the example shown in Figure 10, the segmented inspection area 511 has a vertical line pattern. When setting optical adjustments for a line pattern, the proportion of edge appearances in each direction of the line pattern is determined, as will be described later. In this example, the segmented inspection area 511 contains multiple vertical lines extending in the y direction. In the x direction, multiple edges of multiple lines appear. For example, one line 1002 is a vertically elongated rectangle and has two edges, 1003 and 1004, on the left and right in the x direction. Within the segmented inspection area 511, for example, 14 edges appear in the x direction, but no edges appear in the y direction. In this way, the proportion of edge appearances in the x and y directions can be considered as a feature of the pattern. Based on this proportion, the optical adjustment execution items and execution parameter values ​​can be determined.

[0137] [S109, S110: Operating conditions for optical adjustment] In steps S109 and S110, the computer 201 determines and sets the optical adjustment operation conditions for each segmented inspection area for the group of segmented inspection areas determined up to step S108. In Embodiment 1, the optical adjustment operation conditions broadly consist of the following two pieces of information: (1) the optical adjustment execution items and execution parameter values; and (2) the optical adjustment execution locations and optical adjustment necessity determination locations. In step S109, the computer 201 determines and sets the optical adjustment execution items and execution parameter values ​​for each group of segmented inspection areas. In step S110, the computer 201 determines and sets the optical adjustment execution locations and necessity determination locations for each segmented inspection area.

[0138] [Optical adjustment execution items and execution parameter values] First, as an example of the process in step S109, we will describe an example of determining the optical adjustment execution items and execution parameter values.

[0139] Optical adjustments for the SEM100 include adjusting the beam shape, beam diameter, trajectory, irradiation energy, and density of the primary electron beam 4 used to inspect the wafer 7 in Figure 1, as well as the secondary electrons 9 and backscattered electrons 9b emitted from the wafer 7. In addition, these optical adjustments include adjusting the signal amplification factor and image processing, which are necessary for outputting the signals incident on the secondary electron detector 10 and the backscattered electron detector 10b as images.

[0140] In Embodiment 1, the optical adjustment execution items include the following as candidates:

[0141] Execution Item 1: Autofocus (AF): Autofocus is the focusing of the primary electron beam 4 using the objective lens 6 shown in Figure 1. The objective lens 6 is an example of an optical adjustment device for AF.

[0142] Execution Item 2: Automatic Stigmation (AST): Automatic astigmation correction is the correction of astigmatism in the primary electron beam 4 using the astigmatism corrector 20 shown in Figure 1. The astigmatism corrector 20 is an example of an optical adjustment device for AST.

[0143] Execution Item 3: Orbital Correction of Secondary Electron or Backscattered Electron Beam: This orbital correction is performed using a secondary electron aligner 21 to ensure that, for example, the beam of secondary electrons 9 is properly incident on the secondary electron detector 10. The secondary electron aligner 21 is an example of an optical adjustment device for this orbital correction. Orbital correction for backscattered electrons 9b is possible in a similar manner.

[0144] Execution Item 4: Beam Current Value Adjustment: This beam current value adjustment function adjusts the beam current value by changing the voltage applied to the extraction electrode 4 in Figure 1 when the beam current value deviates from the set value of the optical conditions. The extraction electrode 4 is an example of an optical adjustment device for this beam current value adjustment.

[0145] Execution Item 5: Correction of the axis center of the primary electron beam, etc.: This correction involves correcting the axis center of the primary electron beam 4 using deflectors 5 (5a, 5b) as optical adjustment devices.

[0146] Execution Item 6: Automatic Brightness / Contrast Control (ABCC): This ABCC function adjusts the brightness and contrast of the image by changing the amplification factor of the detection system, including the secondary electron detector 10, using the amplifier 11, so that the histogram of the SEM100 image fits within the full grayscale range. Furthermore, ABCC also includes a function to perform adjustments by software program processing so that the image histogram fits within the full grayscale range after the analog signal is converted to a digital signal by the A / D converter 12. An example of an optical adjustment device for ABCC is part of the amplifier 11, A / D converter 12, and arithmetic processing unit 14.

[0147] In Embodiment 1, the optical adjustment execution item is selected from the execution items 1 to 6 described above. Basically, the computer 201 automatically selects the execution item, and the user can confirm, apply, or change the selected execution item. The user can confirm and select whether or not to apply the optical adjustment execution item on a screen like the one shown in Figure 7.

[0148] Each execution item requires a different pattern to accurately perform the corresponding AF (autofocus) and other functions. In other words, if the optical adjustment function performed is not appropriate for the patterns included in each segmented inspection area, the adjustment state may actually worsen. Therefore, it is desirable to determine the optical adjustment execution item to be applied for each segmented inspection area, or in other words, for each pattern included within it.

[0149] Therefore, in this inspection system, the setting of optical adjustment execution items and execution parameter values ​​in step S109 is performed on a unit basis of the grouped divided inspection areas in step S108. In other words, the optical adjustment execution items and execution parameter values ​​are determined for each group. In the example in Figure 7, the divided inspection areas belonging to group A (divided inspection areas 511 and 512 in Figure 5) have, for example, AF and ABCC set as essential optical adjustment execution items. Since optical adjustment of AST is not appropriate for the pattern of group A, AST is set as "not" as an optical adjustment execution item.

[0150] Computer 201 determines the optical adjustment execution items for each group of segmented inspection areas, and then determines the execution parameter values ​​corresponding to those execution items. The optical adjustment execution parameters can be broadly categorized into the following two types:

[0151] The first type of execution parameters are the parameters of the electron optical system that constitutes the SEM100, such as the amplitude, step size, and initial value of the objective lens 6 and deflection coil 3 in Figure 1. In optical adjustment, the parameter values ​​of the electron optical system are allocated and images are acquired, and the optimal parameter values ​​of the electron optical system are calculated from how the image quality changes. Therefore, in this optical adjustment, it is desirable to set the amplitude and other parameters appropriately for each group of segmented inspection areas, or in other words, for each pattern contained within them.

[0152] The second type of execution parameter is the imaging conditions for the images acquired by the SEM100 during optical adjustment. For example, if the pixel resolution is set too low despite the pattern being fine, it will be impossible to correctly determine the variation in image quality from the acquired image, and the accuracy of the optical adjustment will decrease. Therefore, it is desirable to appropriately set the image imaging field size, pixel size, scan speed, rotation, and number of integrated frames according to the pattern.

[0153] Therefore, this inspection system also sets the optical adjustment execution parameter values ​​in step S109 on a unit basis, such as in groups of divided inspection areas. In other words, the optical adjustment execution parameter values ​​are determined for each group.

[0154] In the example in Figure 7, the parameter values ​​for AF (para1 to paraN) and ABCC (para1 to paraN) are set for the segmented inspection area belonging to group A. Details of each parameter are set for each execution item. For example, the first parameter param1 in AF is a parameter of the objective lens 6, and the first parameter param1 in ABCC is a parameter of the amplifier 11.

[0155] Setting the optical adjustment execution items and execution parameter values ​​for each group of divided inspection areas has the following advantages. Consider a case where the user wants to manually fine-tune and optimize the optical adjustment execution items and execution parameter values ​​that have been automatically set by the computer 201. In the prior art example, even if most of the patterns included in the inspection point area are similar patterns, it is necessary to readjust the execution items and parameter values ​​for each inspection point, which is time-consuming. In contrast, in Embodiment 1, since the inspection area is divided into groups according to pattern classification, it becomes possible to modify the optical adjustment execution items and execution parameter values ​​for multiple inspection points, including similar patterns, all at once for each group. This greatly reduces the user's workload.

[0156] The execution parameter values ​​for optical adjustment are the parameter values ​​related to the hardware and software of the optical adjustment device shown in Figure 1 above. For example, in the case of ABCC, the execution parameter values ​​may also include the parameter values ​​of the software program processing performed by the arithmetic processing unit 14 of the computer 201.

[0157] On the other hand, while manual setting of optical adjustment items and execution parameter values ​​for each group is possible by the user, this may become burdensome for the user if there are many pattern classifications and groups. Therefore, in order to further reduce the user burden, the inspection system of Embodiment 1 also has a function that allows the computer 201 to automatically set the optical adjustment items and execution parameter values ​​for each group. That is, initially, the computer 201 automatically determines the appropriate optical adjustment items and execution parameter values ​​for each group and displays them on the screen. The user can then check the items and execution parameter values ​​on the screen and change them as needed. This function is also a new function that has not been seen in conventional systems.

[0158] In the inspection system of Embodiment 1, the computer 201 automatically determines the optical adjustment execution items and execution parameter values ​​for each group, using as indicators, for example, the pattern features (1) to (5) shown below and the manufacturing process information (6).

[0159] (1) First feature: presence or absence of pattern: This inspection system uses the presence or absence of a pattern to set the items to be performed on optical adjustment within the inspection area. For example, this inspection system sets it so that optical adjustment is not performed if the segmented inspection area is classified as a group without any particular pattern (e.g., label C in Figure 5).

[0160] (2) Second feature: Pattern density: This inspection system uses the pattern density to set image acquisition parameters in optical adjustment. For example, in segmented inspection areas where the pattern is classified into a sparse group, this inspection system increases the field of view size by changing the number of pixels or pixel size so that the pattern is included within the field of view of the image acquired during optical adjustment.

[0161] (3) Third feature: Size: This inspection system uses size to set the amplitude and step size of optical parameters in optical adjustment, and to set the image acquisition parameters. For example, in segmented inspection areas classified into groups of fine patterns, this inspection system sets the amplitude of optical parameters to be small and also reduces the pixel size to increase the pixel resolution of the image.

[0162] (4) Fourth feature: Two-dimensional shape: This inspection system uses the two-dimensional shape to set the items to be performed for optical adjustment within the inspection area. For example, for an item such as AST, a pattern is required in which the appearance ratio of edges in the x and y directions is equal in order to perform aberration correction in both the x and y directions. Therefore, this inspection system is set so that in divided inspection areas classified into groups in which edges appear only in a specific direction, such as the line pattern area shown in Figure 10, AST is not performed, or only astigmatism correction is performed in the direction in which the edges appear.

[0163] (5) Fifth feature: Three-dimensional shape: This inspection system uses the three-dimensional shape to set the range of motion, step size, and initial value of optical system parameters within the inspection area, and to set an offset for the optical adjustment results. For example, in the region of a contact hole with a high aspect ratio, this inspection system adds an offset to the adjustment results of the optical system parameters so that optimal optical adjustment can be performed for observing the bottom of the hole.

[0164] (6) Manufacturing process information: This inspection system uses the manufacturing process information 233 in Figure 2 to set the image imaging parameters in optical adjustment. The manufacturing process information is, for example, information that represents processes such as etching and deposition performed on the target sample 7. In general, the image quality of the obtained SEM image differs depending on the manufacturing process. This inspection system, for example, increases the scan time for the beam in manufacturing processes where it is not possible to obtain SEM images with a high signal-to-noise ratio. Also, in processes where pattern shrinkage due to beam irradiation is likely to occur, such as the resist manufacturing process (ADI), this inspection system shortens the scan time for the beam to reduce shrinkage.

[0165] Embodiment 1 shows an example of setting the operating conditions for optical adjustment for a line pattern with a width of 50 nm and a pitch of 100 nm in a manufacturing process that is less prone to static charge, as the pattern of sample 7.

[0166] Regarding the optical adjustment items determined in step S109, specific examples of AF and AST, which are set relatively frequently, are described here.

[0167] First, regarding autofocus (AF), since focusing is required, computer 201 is basically set to execute. Next, computer 201 sets the swing range, step size, etc. for AF. In the example of Embodiment 1, the default settings of SEM100 are applied because the pattern size is not as small as in the EUV process, but values ​​other than the default may be set depending on the pattern size, etc. For the image acquisition conditions when AF is executed, computer 201 sets the pixel size to 2nm / pix and the number of pixels to 512pix×512pix so that the pattern can be sufficiently placed within the field of view.

[0168] Next, the computer 201 configures the AST settings. In the example of Embodiment 1, since the line pattern shown in Figure 10 does not have edges appearing in equal proportions in the x and y directions, the computer 201 configures not to perform AST. Alternatively, it is possible to configure the computer to perform astigmatism correction only in the direction in which edges appear (for example, the x direction in Figure 10). Furthermore, it is possible to configure the computer to correct astigmatism in both the x and y directions by performing AST correction in both scanning directions, x and y.

[0169] On the other hand, depending on the setting of the imaging field size per inspection point (step S105) as described above, it is possible that the imaging field may cross between the inspection area and the non-inspection area at the outer edge of the inspection area. In such cases, the inspection system sets the optical adjustment execution items and execution parameter values ​​to prioritize imaging that matches the image quality to the set inspection area pattern.

[0170] [Locations where optical adjustments are performed and where the necessity of adjustments is determined] Next, we will explain how to determine and set the locations for optical adjustment execution and necessity determination in step S110. It is desirable to optimize these settings according to the size and location of the inspection area. For this reason, the inspection system of Embodiment 1 may set the locations for optical adjustment execution and necessity determination for each group, but when optimizing as described above, these locations are determined individually for each divided inspection area. The inspection system of Embodiment 1 also has a function to automatically set these locations in order to reduce the burden on the user.

[0171] Optical adjustment execution locations are locations where optical adjustment must be performed, or in other words, locations where it is mandatory. These locations are arranged within the segmented inspection area, along the movement trajectory, for example, at regular intervals. These regular intervals are defined by distance intervals or time intervals. The size of these intervals is set for each target sample 7 and manufacturing process, within a range that maintains the inspection sensitivity required by the SEM 100. In the example of Embodiment 1, the automatic setting method for optical adjustment execution locations and locations for determining necessity of AF, and in particular, the determination of a suitable arrangement interval, will be described.

[0172] Figure 11 is an explanatory diagram illustrating an example of setting optical adjustment execution locations and necessity determination locations for an inspection area. Figure 11 shows an example of determining the spacing of optical adjustment execution locations and necessity determination locations in a given inspection area based on the wafer height distribution data shown at the top. The bottom of Figure 11 shows inspection area 1100 as an example of an inspection area for wafer 7, and has, for example, a vertical line pattern. Correspondingly, the top shows a graph representing the relationship between the position / distance in the x-direction [μm] and the wafer height distribution (resolution equivalent) [nm] as wafer height distribution data.

[0173] The SEM100 currently in use has a maximum resolution of 2 nm, while the inspection sensitivity required for inspecting wafer 7 is 4.8 nm in terms of resolution. In this case, for example, the AF execution interval can be determined from the resolution distribution calculated from the wafer height distribution shown in Figure 11, which has been measured in advance. In the example in Figure 11, it is shown that the resolution related to wafer height deteriorates by 2.8 nm when moving 1000 μm in the x direction. In this case, when determining the optical adjustment execution locations for AF in inspection area 1100, the inspection system decides to place consecutive execution locations within 1000 μm of each other in the x direction, corresponding to the imaging order shown by the dashed arrows. This distance interval of 1000 μm corresponds to the above-mentioned 2.8 nm deterioration in resolution. In this example, the optical adjustment execution locations (e.g., locations 1101 and 1102) indicated by white dots are arranged at this distance interval of 1000 μm. By keeping the spacing between optical adjustment points within 1000 μm, it is possible to prevent a degradation of resolution of 2.8 nm or more.

[0174] In addition to determining the spacing of the optical adjustment execution locations, this inspection system also determines the locations where optical adjustment is required or not. If the judgment result at a location indicates that optical adjustment is required, the optical adjustment is performed at that location; otherwise, the optical adjustment at that location is skipped. To ensure that this inspection system can handle unexpected local resolution changes caused by sample 7 or SEM100, the optical adjustment requirement determination locations are placed within a 1000 μm distance interval of the optical adjustment execution locations as a safety margin. In this example, as indicated by the diamond-shaped dots, location 1103, which is the optical adjustment requirement determination location, is placed at a distance of 500 μm from locations 1101 and 1102, which are optical adjustment execution locations. This 500 μm distance interval between the execution location and the requirement determination location is an example where the distance interval of 1000 μm is half that of the optical adjustment requirement determination locations.

[0175] Furthermore, the lower section shows another example with enhanced assurance, where locations 1103 and 1104, which are locations for determining whether optical adjustment is necessary, are positioned at a distance of approximately 333 μm, which is 1 / 3 the distance between locations 1101 and 1102, which are locations where optical adjustment is performed.

[0176] On the other hand, there are execution items that should be performed at regular time intervals due to changes over time, such as the optical axis adjustment in execution item 5 mentioned above. For such execution items, this inspection system can set the optical adjustment execution locations and the locations for determining whether they are necessary, based on data on the change in the optical axis over time that has been acquired in advance, similar to the setting for AF in Figure 11. In this case, the distance intervals in Figure 11 should be replaced with time intervals.

[0177] On the other hand, even if the required inspection sensitivity for the SEM100 is known to some extent, there are cases where prior data such as wafer height distribution and data on the SEM100's changes over time cannot be obtained. In such cases, the interval for performing optical adjustments can be optimized in the following way. First, the inspection system places optical adjustment execution locations and necessity determination locations in the inspection area based on the default setting interval. Then, the inspection system performs a test inspection in a part of that inspection area. Once the test inspection is completed, the inspection system rearranges the optical adjustment execution locations and necessity determination locations based on the optical adjustment necessity determination results during the test inspection. The optical adjustment necessity determination results during the test inspection are the necessity determination results at the optical adjustment necessity determination locations that were set initially, and the inspection system pre-sets the acceptable variation in the index value of the image quality based on the required inspection sensitivity for the SEM100.

[0178] For example, if all of the initially set optical adjustment necessity / determination points are determined to require adjustment, this inspection system shortens the spacing between the optical adjustment execution points and necessity / determination points compared to the initial setting. On the other hand, if all of the initially set optical adjustment necessity / determination points are determined to be negligible, this inspection system either maintains the initial setting or widens the spacing compared to the initial setting. When the spacing is changed, this inspection system reruns the test inspection and repeats the same cycle. This allows for optimization of the placement of optical adjustment execution points and necessity / determination points even without prior data.

[0179] Furthermore, the optical adjustment execution locations and necessity determination locations can be managed as data / information, for example, as position coordinates in the coordinate system of the surface of sample 7. In Embodiment 1, the optical adjustment execution locations and necessity determination locations are set to the same position coordinates as the inspection point. Therefore, the optical adjustment execution locations and necessity determination locations can be managed using the position coordinates of the inspection point. However, this is not limited to this, and in modified examples, the optical adjustment execution locations and necessity determination locations may be set to position coordinates near the position coordinates of the inspection point. In addition, the optical adjustment execution locations and necessity determination locations are not limited to position coordinates in the coordinate system of the sample, but may also be set and managed using, for example, position, distance, or time on the movement trajectory.

[0180] As a result of steps S109 and S110 above, optical adjustment operating conditions are set for each segmented inspection area within each group. In the example in Figure 5, optical adjustment operating condition A521 is set for segmented inspection areas 511 and 512 of group A501, optical adjustment operating condition B522 is set for segmented inspection areas 513 and 514 of group B502, and optical adjustment operating condition C523 is set for segmented inspection area 515 of group C. The content of the optical adjustment operating conditions may differ for each segmented inspection area.

[0181] [Test recipe and test execution] After all the optical adjustment operating conditions for the inspection area of ​​the target wafer 7 have been determined up to step S110, in step S111, the computer 201 of this inspection system sets the optical conditions for the area inspection and the imaging conditions for the inspection area. The optical conditions for the area inspection include the acceleration voltage, irradiation voltage, and irradiation current value of the primary electron beam 4 shown in Figure 1, which are set in advance. The imaging conditions for the inspection area include the imaging field size, pixel size (in other words, magnification), scan speed, number of frames, and scan angle. The imaging field size has already been set in step S105. Note that the setting of the optical conditions and imaging conditions here are known setting elements separate from the setting of the optical adjustment operating conditions in steps S109 and S110.

[0182] The computer 201 then generates an inspection recipe that includes the above optical adjustment operating conditions, the optical conditions during the inspection of the inspection area, and the imaging conditions of the inspection area, and saves it in the database (inspection recipe information 238 in Figure 2). The optical adjustment operating conditions refer to the adjustments and operating conditions of the electron optical system of the SEM 100, etc., performed by this inspection system to optimize the state of the primary electron beam 4, etc., in order to obtain a high-quality and stable SEM image while performing the inspection under the specified optical conditions.

[0183] In step S112, the inspection system performs area inspection according to the inspection recipe in step S111. Computer 201 of the computer system 200 controls the SEM 100 according to the inspection recipe, causing the SEM 100 to perform operations such as imaging for area inspection. Computer 202 receives and acquires the image captured by the SEM 100 through computer 201, and uses that image to perform inspection processing with the inspection processing unit 16. Examples of inspection processing include pattern dimension measurement and defect detection. Computer 202 generates inspection result information and saves it in the database (inspection result data 252 in Figure 2). Computer 202 also outputs the inspection result information to the GUI screen.

[0184] [Regarding imaging during the examination] During the execution of the region inspection according to the inspection recipe (step S112), imaging and inspection are performed at each inspection point within the segmented inspection area on the movement trajectory. In region inspection, an image for inspection is acquired at each inspection point. The general outline of the operations such as imaging at each inspection point is as follows.

[0185] (1) The SEM100 is positioned at the target examination point by moving Stage 8, and the imaging field of view is set. The imaging field of view is set with the examination point at the center.

[0186] (2) The SEM100 performs pre-imaging optical adjustment, or in other words, beam adjustment, in the imaging field of view of the target inspection point. Conventionally, this optical adjustment is performed for each inspection point, but in Embodiment 1, it is performed according to the optical adjustment operation conditions of the inspection recipe. That is, if the inspection point is an optical adjustment execution location, optical adjustment is performed with the specified execution items and execution parameter values. If the inspection point is not an optical adjustment execution location, pre-imaging optical adjustment is not performed.

[0187] (3) The SEM100 scans the imaging field of view (for example, an area of ​​1 μm × 1 μm) of the inspection point with the primary electron beam 4 and captures an image based on the detection signal of the secondary electron detector 10. The captured image is acquired by the computer 202 via the computer 201. The computer 202 uses the image as an inspection image and performs inspection processing. Note that the inspection processing for each inspection point may be performed all at once later.

[0188] [Regarding the determination of whether optical adjustment is necessary during the inspection] Figure 12 shows the processing flow as an explanatory diagram for the execution of optical adjustment and necessity determination performed during the execution of area inspection according to the inspection recipe (step S112). In step S1201, SEM100 checks whether a reference point (e.g., inspection point) within the divided inspection area is an optical adjustment execution point or a necessity determination point. If it is a necessity determination point, SEM100 performs a necessity determination in step S1202. Note that if neither an execution point nor a necessity determination point is set at the inspection point, the processing in Figure 12 is not performed. The necessity determination is performed by, for example, the following methods. Any of the following methods are applicable.

[0189] (1) First method: In step S1203, the SEM100 first captures a judgment image at the reference point, which is the point for determining necessity. In step S1204, the SEM100 uses the captured judgment image to perform image quality evaluation, etc. Image quality evaluation includes, for example, determining whether the image quality index value calculated from the captured image meets a predetermined judgment criterion. In step S1205, the SEM100 determines whether optical adjustment is necessary based on the image quality evaluation result. In step S1206, if the judgment result indicates that adjustment is necessary, the SEM100 performs optical adjustment at that point in step S1207. Then, in step S1208, the SEM100 captures an inspection image at that inspection point, in the state after optical adjustment.

[0190] If the SEM100 determines in step S1206 that the necessity determination is not performed, it will not perform the optical adjustment in step S1207 and will instead acquire an inspection image in step S1208. If the reference point in step 1201 is an optical adjustment point, the SEM100 will proceed to step S1207, perform the optical adjustment at that inspection point, and then acquire an inspection image in step S1208. The above flow is repeated similarly for each reference point.

[0191] (2) Second method: The following second method may be applied. The second method differs in the processing within step S1202. SEM100 first acquires an inspection image at the reference location, which is the necessity determination location. SEM100 uses the acquired inspection image to perform image quality evaluation and other evaluations, and determines whether optical adjustment is necessary based on the evaluation results. If the determination result is necessary, SEM100 performs optical adjustment. Since the inspection image has already been acquired, it proceeds to the processing of the next reference location. If the determination result is not necessary, SEM100 proceeds to the processing of the next reference location without performing optical adjustment. In this method, if optical adjustment is performed at one reference location, it will be reflected in the imaging at the next reference location.

[0192] This inspection system pre-sets criteria for image index values ​​used in the image quality evaluation for the necessity determination described above. These criteria are determined, for example, based on the inspection sensitivity required for the SEM100 for the inspection area set by the user. The user may also set the desired inspection sensitivity and criteria (in other words, thresholds for necessity determination) on the GUI screen. In that case, this inspection system determines the above criteria based on the user's settings. The settings information is saved, for example, as part of the inspection setting information 236 in Figure 2.

[0193] Typical image quality indicators that can be used in the above image quality evaluation include resolution in each angular direction, brightness, contrast, signal-to-noise ratio, and distortion. These image quality indicators are judged, for example, in the case of AF, by the average resolution of the entire image; in the case of AST, by the difference in resolution in the x and y directions; and in the case of ABCC, by the brightness and contrast of the image.

[0194] [Regarding processing time] Figure 13 illustrates the time required for processing at the optical adjustment execution location and the necessity / determination location. In Figure 13, the horizontal axis represents time, and the vertical axis, from top to bottom, shows: (a) processing at the optical adjustment execution location, (b) processing when the determination result is negative at the optical adjustment necessity / determination location, and (c) processing when the determination result is positive at the optical adjustment necessity / determination location. In (a), there is only optical adjustment 1301 as a processing block. In (b), there is only necessity / determination 1302. In (c), there is necessity / determination 1303 and optical adjustment 1304. As shown in the figure, optical adjustment generally takes longer than necessity / determination processing. More specifically, the time required for optical adjustment may vary depending on the execution item such as AF. The processing time is shortest in case (b), followed by (a), and then longest in case (c). The more often the determination result at each optical adjustment necessity / determination location in the inspection area is negative, the shorter the overall processing time will be.

[0195] The optical adjustment necessity determination points are positioned as a guarantee, for example, between optical adjustment execution points, as mentioned above. Therefore, it is expected that the optical adjustment necessity determination result will be negative in most cases, and that the determination result will not be necessary in most cases overall. For this reason, it is expected that the processing time for most optical adjustment necessity determination points will be as shown in (b). If optical adjustment necessity determination points are appropriately placed as a guarantee, rather than only containing optical adjustment execution points in the inspection area, the time at each point will decrease from (a) to (b), and the overall processing time can be expected to be shortened.

[0196] The reason why the time required for the necessity determination process is shorter than the time required for the optical adjustment process is as follows: In optical adjustment, it is necessary to acquire multiple images by varying multiple parameter values ​​to determine the optimal parameter values, and there are multiple execution items. In contrast, for necessity determination, it is sufficient to acquire only one image for the determination. Therefore, the time required for necessity determination is shorter than the time required for optical adjustment. The time required will vary depending on the execution conditions of the optical adjustment process, the acquisition conditions for the image used for determination, and the determination conditions, but in most cases, the time required for necessity determination will be several to tens of times shorter than the time required for optical adjustment. Therefore, a method of setting the location for optical adjustment necessity determination is effective in improving throughput.

[0197] [Example of layout for optical adjustment execution area and necessity determination area] Figure 14 illustrates an example of the placement of the optical adjustment execution area and the necessity determination area. These areas can be arranged in various ways, taking into account factors such as inspection sensitivity and throughput. The following examples will explain the placement examples and their respective effects in comparison with conventional technology examples.

[0198] Figure 14(a) shows an example of the settings in the comparative example. Within a certain inspection area 1400, there are multiple inspection points, for example, points p1 to p10 (shown as small white circles) aligned in the x direction. In this comparative example, optical adjustment execution locations (for example, locations a1 to a10) are set for all of the multiple inspection points. The optical adjustment execution locations are shown as large white circles. The interval between consecutive inspection points is shown as interval 1401. In this case, as mentioned in the problem, high inspection sensitivity can be ensured, but the overall inspection time may be long, resulting in low throughput. In this case, the actual sensitivity may be excessive compared to the required sensitivity.

[0199] (b) shows a first setting example in Embodiment 1 for the same inspection area 1400 as in (a). In this example, only optical adjustment execution locations (e.g., locations a1 to a5) are arranged for 10 inspection points (points p1 to p10) in the inspection area 1400. In this example, optical adjustment execution locations are arranged at intervals and densities of one every two points. This example corresponds to a configuration in which the optical adjustment execution locations are reduced compared to (a). The distance spacing of the execution locations is determined so as to ensure inspection sensitivity. In this case, it is possible to reduce the inspection time and increase throughput compared to (a) while ensuring sufficient sensitivity.

[0200] (c) shows a second setting example in Embodiment 1 for the same inspection area 1400 as in (a). In this example, both optical adjustment execution locations and optical adjustment necessity determination locations are arranged. In this example, optical adjustment execution locations (e.g., locations a1 to a5) are arranged at intervals or densities of one every two points, and optical adjustment necessity determination locations (e.g., locations b1 to b5) are arranged alternately with respect to these locations at intervals or densities of one every two points. The interval 1401 between adjacent execution locations and determination locations is the same as the interval 1401 between inspection points.

[0201] This example corresponds to a configuration in which, compared to (a), the optical adjustment execution points are reduced as in (b), and then the optical adjustment necessity / determination points are replaced with these points. In this case as well, it is possible to reduce the inspection time and increase throughput compared to (a) while ensuring sufficient sensitivity. The reason for the reduction in inspection time is as explained in Figure 13. In this case, the threshold for determining whether optical adjustment is necessary (the judgment criteria for the image quality evaluation value mentioned above) is set so that the result of the optical adjustment necessity / determination is negative in most cases, as in (b) of Figure 13. However, if this threshold for determining whether optical adjustment is necessary / needed is set too strictly, the number of results requiring adjustment increases, as in (c) of Figure 13, making it more difficult to increase throughput.

[0202] (d) shows a third setting example in Embodiment 1 for the same inspection area 1400 as in (a). In this example, both optical adjustment execution locations and optical adjustment necessity determination locations are arranged for 10 inspection points. In this example, optical adjustment execution locations (e.g., locations a1 to a3) are arranged at intervals or densities of 4 points, and optical adjustment necessity determination locations (e.g., locations b1, b2) are arranged at intervals or densities of 4 points, alternating with the execution locations, with intervals 1402 between them. The interval 1402 between adjacent execution locations and determination locations is twice the inspection point interval 1401.

[0203] This example corresponds to a configuration where the spacing between the two types of locations is increased and the density is lower compared to (c). In this case, the sensitivity is lower than in case (c), but the throughput is higher. In this case, a balance can be achieved in which throughput is prioritized over sensitivity.

[0204] (e) shows a fourth setting example in Embodiment 1 for the same inspection area 1400 as in (a). In this example, only optical adjustment necessity determination points are arranged for 10 inspection points. In this example, optical adjustment necessity determination points (e.g., points b1 to b5) are arranged at intervals and densities of one point every two points. In this case, the sensitivity is lower than in (a), but the throughput can be increased significantly. For example, when the required sensitivity is not very high, a balance that prioritizes high throughput can be achieved by using this setting example.

[0205] (f) shows a fifth configuration example in Embodiment 1 for the same inspection area 1400 as in (a). In this example, as with (c) and (d), both optical adjustment execution locations and optical adjustment necessity determination locations are arranged for 10 inspection points. In this example, optical adjustment execution locations (e.g., locations a1, a2) are arranged at intervals or densities of 8 points, and optical adjustment necessity determination locations (e.g., location b1) are arranged alternately with these locations at intervals or densities of 8 points. The interval 1403 between adjacent execution locations and determination locations is four times the inspection point interval 1501. In this case, throughput can be increased even more significantly than in the case of (d).

[0206] [Regarding sensitivity and throughput] As shown in the example above, the inspection system of Embodiment 1 sets at least one of the optical adjustment execution location and the optical adjustment necessity determination location for each divided inspection area. In particular, in examples such as Figure 14(d), both are set. By appropriately selecting the spacing, number, and density of these locations for multiple divided inspection areas of the inspection area, the sensitivity and throughput of the inspection can be balanced to the user's desired level. Although sensitivity and throughput are basically in a trade-off relationship, they can be brought closer to the balance desired by the user. For example, in the setting examples of Figure 14(c),(d), and(f), the density of the optical adjustment execution location and the necessity determination location decreases in that order, and the throughput increases in that order.

[0207] In Embodiment 1, the basic principle is to set both optical adjustment execution locations and optical adjustment necessity determination locations in the divided inspection area, as shown in Figure 14(d), for example. However, the system is not limited to this, and it is also possible to set only optical adjustment execution locations (for example, Figure 14(b)) or only optical adjustment necessity determination locations (for example, Figure 14(e)). For example, if sensitivity and stability are important, the inspection system may set only the optical adjustment execution locations at intervals that satisfy the desired sensitivity. Conversely, if the priority is to reduce inspection time and throughput, the inspection system may set only the optical adjustment necessity determination locations at intervals that satisfy the desired sensitivity. Furthermore, the user may be able to select a combination of these two types of locations on a GUI screen.

[0208] [Saving and reusing optical adjustment operating conditions] The optical adjustment operation conditions set up to step S110 above can be saved separately from the inspection recipe in a database (for example, optical adjustment setting information 237 in Figure 2) and reused later. For example, the above optical adjustment operation conditions can be reused to set up the inspection of a wafer 7 that is the same semiconductor device but manufactured using a different process. However, in this case, the required inspection sensitivity may change due to the difference in manufacturing processes. Therefore, it is desirable to make fine adjustments to the optical adjustment execution locations and necessity / determination locations, taking this into consideration. Fine adjustments include adjustments to the number and spacing of the optical adjustment execution locations and necessity / determination locations mentioned above. Such fine adjustments to the optical adjustment operation conditions will be explained in Embodiment 3 below.

[0209] [Regarding the imaging order and movement trajectory] During region inspection, this inspection system sequentially references segmented inspection regions, multiple inspection points, and optical adjustment execution locations along the imaging sequence, or in other words, the movement trajectory, as defined in the inspection recipe. For example, when the inspection system starts inspecting the first segmented inspection region and reaches an optical adjustment execution location, it applies optical adjustments to the SEM100 based on the execution items and execution parameter values ​​set for that segmented inspection region group in the inspection recipe. Furthermore, when the inspection system reaches a location where optical adjustment is required, it performs a determination of whether adjustment is necessary at that location, as shown in Figure 12, and if the determination result indicates that adjustment is required, it similarly performs optical adjustments at that location.

[0210] Figure 15 is an explanatory diagram of the imaging sequence, or in other words, the movement trajectory. During region inspection, the SEM100 sequentially references multiple segmented inspection regions within the inspection area of ​​the target sample 7, and sequentially references multiple inspection points within each segmented inspection region to perform imaging and other operations. For example, mechanical movement of the stage 8 requires a predetermined amount of time, so in order to increase the overall inspection throughput, it is more desirable to determine an inspection recipe that includes optical adjustment operation conditions, taking into account operations such as positioning and changing the field of view in response to the movement of the stage 8.

[0211] Figure 15 shows an example of the imaging sequence and movement trajectory. In Embodiment 1, for example, there are multiple segmented inspection areas (e.g., Figure 5), and each segmented inspection area has multiple inspection points (e.g., Figure 10). In this case, in Embodiment 1, the imaging sequence and movement trajectory shown in Figure 15 are used as a basis for each segmented inspection area. Furthermore, in Embodiment 1, the imaging sequence and movement trajectory are selected so that the movement from the last inspection point of the previous segmented inspection area to the first inspection point of the next segmented inspection area is as short as possible. The basic idea is that the imaging sequence and movement trajectory are set so that the distance and time of movement of the stage 8 are minimized in order to perform imaging etc. by moving sequentially between segmented inspection areas and inspection points.

[0212] Figure 15(A) shows the first example of a movement trajectory. For example, in one segmented inspection area 1500, there are 100 points p1 to p100 as multiple inspection points. The first example is an example of a trajectory that moves in a zigzag pattern in linear order. In the first example, SEM100 changes its field of view based on the movement of Stage 8, for example, starting from the upper left inspection point p1 and sequentially referencing multiple points p1 to p10 to the right along the x-direction. Next, SEM100 moves down one row in the y-direction and moves to sequentially referencing points p11 to p20 in the second row to the left along the x-direction. Similarly thereafter, inspection points in odd-numbered rows are referenced to the right in the x-direction, and inspection points in even-numbered rows are referenced to the left in the x-direction.

[0213] Figure 15(B) shows a second example of a movement trajectory. For example, in one inspection area 1500, there are 100 points, p1 to p100, as multiple inspection points. The second example is an example of a trajectory that moves linearly in one direction. In the second example, SEM100 changes its field of view based on the movement of Stage 8, for example, starting from the top left inspection point p1 and sequentially referencing multiple points p1 to p10 along the x-direction to the right. Next, SEM100 moves down in the y-direction to return to the beginning of the second row and sequentially referencing points p11 to p20 of the second row along the x-direction to the right. Similarly thereafter, each inspection point in each row is referenced to the right in the x-direction.

[0214] Beyond the examples above, the imaging sequence and movement trajectory should be set to be as efficient as possible. Other examples include rotating the movement trajectory of the first example by 90 or 180 degrees, or moving linearly in the y-direction instead of the x-direction.

[0215] The following is an example of the processing related to setting the imaging order and movement trajectory. First, the user sets the inspection area (step S105). The computer 201 sets one or more divided inspection areas based on the design layout information 231, etc., by performing the pattern classification described above (step S108, Figures 4 and 5). The computer 201 sets multiple inspection points for each divided inspection area (step S108, Figure 10). In step S108, the computer 201 determines the imaging order and movement trajectory for one or more divided inspection areas and multiple inspection points within each divided inspection area.

[0216] In this case, the imaging sequence and movement trajectory are determined as follows. For example, suppose there are two separate segmented inspection areas, a first and a second. The imaging sequence is as follows: First, move to a predetermined starting point within the first segmented inspection area, and then sequentially access all inspection points from that starting point to a predetermined ending point, as shown in the example in Figure 15. Next, the imaging sequence is as follows: move from the ending point of the first segmented inspection area to a predetermined starting point within the second segmented inspection area, and then sequentially access all inspection points from that starting point to a predetermined ending point, as shown in the example in Figure 15. The same applies when there are three or more segmented inspection areas.

[0217] The order in which multiple segmented inspection areas are referenced, as well as the start and end points within each segmented inspection area, should be selected to be as efficient as possible, depending on the relative positions of each segmented inspection area. To maximize throughput, for example, the imaging order can be determined so that the distance from the end point of the first segmented inspection area to the start point of the second segmented inspection area is as short as possible.

[0218] The imaging sequence and movement trajectory described above can be determined automatically by this inspection system. However, if necessary for managing inspection results, the user may set the imaging sequence and movement trajectory for multiple segmented inspection areas and multiple inspection points using the GUI screen. For example, the user can set the imaging and inspection order for multiple segmented inspection areas and multiple inspection points using the GUI screen.

[0219] [Effects of Embodiment 1, etc.] As described above, the inspection system of Embodiment 1 can maintain or improve throughput while maintaining sensitivity when performing area inspection using the SEM 100. The inspection system of Embodiment 1 can achieve area inspection with a balance between sensitivity and throughput desired by the user.

[0220] [Modified example of Embodiment 1] The following modifications of Embodiment 1 are also possible. In Embodiment 1 described above, the method for setting points (in other words, positions) such as optical adjustment execution locations relative to the inspection points of the region inspection was shown as being set in accordance with the position of the inspection points, as in the example above. However, it is not limited to this. In the modifications, the positions of optical adjustment execution locations may be set not at the inspection points themselves, but near the inspection points, on the imaging sequence and movement trajectory. Even with such modifications, effects similar to those of Embodiment 1 can be obtained.

[0221] Figure 16 shows an example of location settings in this modified example. In the example in Figure 16(a), for the inspection area 1600, optical adjustment execution locations are set on the movement trajectory at positions ahead of each inspection point (points p1 to p10), for example, between the previous inspection point and the target inspection point, using a distance interval of 1601.

[0222] In the example in Figure 16(b), the horizontal axis represents the time axis along the movement trajectory, and optical adjustment execution locations are set on this time axis for each determined point in time (e.g., time points t1, t2, etc.). Time interval 1602 indicates the time interval between the placement of optical adjustment execution locations. Time interval 1603 indicates the time interval between the placement of locations for determining necessity for optical adjustment execution locations.

[0223] <Embodiment 2> The inspection system of Embodiment 2 will be explained using Figures 17 to 20. Embodiments 2 and 3 share the same basic configuration as Embodiment 1, with some additions and modifications. The following will mainly describe the components of Embodiment 2 and others that differ from Embodiment 1.

[0224] The inspection system of Embodiment 2 modifies and optimizes the optical adjustment operation conditions set in the inspection recipe for subsequent segmented inspection areas based on the history of optical adjustment operations in the inspected segmented inspection areas along the movement trajectory, while performing area inspection according to the inspection recipe. This modification specifically involves changing the spacing, number, density, etc., of at least one of the optical adjustment execution locations and necessity determination locations for the subsequent segmented inspection areas. In Embodiment 2, this modification can be performed with different spacing settings for each execution item, such as AF, for each segmented inspection area. Furthermore, in Embodiment 2, this modification may be performed on the movement trajectory for, for example, the next current segmented inspection area relative to the previous inspected segmented inspection area. Alternatively, this modification may be performed on multiple segmented inspection areas from the present onward, taking into account statistics for multiple previously inspected segmented inspection areas.

[0225] [Modification and optimization of optical adjustment operating conditions using optical adjustment operation history] In the second embodiment of the inspection system, initially, similar to the first embodiment, the computer 201 generates an inspection recipe for the inspection area. In the second embodiment of the inspection system, the computer system 200 acquires and saves the operation history of optical adjustments during the execution of area inspections according to the inspection recipe. For example, computer 201 or computer 202 stores the operation history information in memory in real time. The computer system 200 refers to the operation history information of optical adjustments in the inspected segmented inspection areas and modifies and optimizes the optical adjustment operation conditions for subsequent segmented inspection areas. The outline of this modification and optimization function is as follows.

[0226] Assume that there are multiple segmented inspection areas along the movement trajectory of the inspection area, for example, a first segmented inspection area, a second segmented inspection area, a third segmented inspection area, etc. The inspection system first images the first segmented inspection area, and at that time, performs optical adjustments as appropriate at the designated optical adjustment execution locations and necessity determination locations according to the optical adjustment operation conditions for the first segmented inspection area in the inspection recipe. The computer system 200 stores the execution result and content of the optical adjustment of the first segmented inspection area as operation history information. Next, the inspection system images the second segmented inspection area. At that time, the inspection system sets the second segmented inspection area as the current segmented inspection area and refers to the operation history information of the inspected first segmented inspection area. Based on the result of the optical adjustment of the first segmented inspection area, the inspection system adjusts the optical adjustment execution locations and necessity determination locations as optical adjustment operation conditions for the second segmented inspection area. Specifically, this inspection system adjusts and rearranges the intervals between optical adjustment execution points and necessity determination points in the second segmented inspection area, based on factors such as the intervals between optical adjustments performed in the first segmented inspection area and the distances between segmented inspection areas.

[0227] [Processing flow] Figure 17 shows the processing flow of the inspection system of Embodiment 2. This flow is for changing and optimizing the optical adjustment operation conditions based on the optical adjustment operation history during the execution of area inspection. First, in step S201, the inspection system moves to the first optical adjustment execution location (first inspection point) in the current divided inspection area (e.g., the second divided inspection area).

[0228] Next, in step S202, the inspection system refers to the set interval Δxp for optical adjustment execution locations and the set interval Δxq for optical adjustment necessity determination locations set in the inspection recipe for the current segmented inspection area (e.g., the second segmented inspection area). The set interval Δxp is, for example, interval 1411 in Figure 14. The set interval Δxq is, for example, interval 1402 in Figure 14. Δxq is smaller than Δxp (Δxq < Δxp).

[0229] In step S203, the inspection system obtains the interval Δx from the last optical adjustment performed in an inspected segmented inspection area (e.g., the first segmented inspection area) to the inspection point of the first optical adjustment performed in the current segmented inspection area. This interval Δx is the distance (or time) calculated along the movement trajectory.

[0230] Then, in steps S204 and S205, the inspection system compares this interval Δx with the set intervals Δxp and Δxq. In step S204, it is determined whether Δx > Δxp, and in step S205, it is determined whether Δx > Δxq. As shown in the figure, if Δx > Δxp and Δx > Δxq, the system proceeds to step S206; if Δx > Δxq and Δx ≤ Δxp, the system proceeds to step S207; and if Δx ≤ Δxp, the system proceeds to step S208.

[0231] In step S206, the inspection system decides to perform optical adjustment at the inspection point. In step S207, the inspection system decides to determine whether optical adjustment is necessary at the inspection point. In step S208, the inspection system decides to skip optical adjustment at the inspection point. These decisions correspond to a change in the optical adjustment operation conditions.

[0232] According to the above flow, if Δx ≤ Δxq, even if the current inspection point is set as the optical adjustment execution location in the inspection recipe, it is determined to be unnecessary without needing to perform a necessity check, and the optical adjustment is skipped (step S208). If Δxq < Δx ≤ Δxp, an optical adjustment necessity check is performed, and if the result of the check is necessary, the optical adjustment is performed; otherwise, it is not performed (step S207). If Δx > Δxp, the optical adjustment is performed as set in the inspection recipe (step S206).

[0233] As a result, in Embodiment 2, optical adjustment can be appropriately omitted while maintaining inspection sensitivity and considering throughput.

[0234] [Example of optical adjustment changes (1)] Figure 18 shows a specific example of changing the optical adjustment operation conditions in Embodiment 2, where the above interval Δx is a distance. In this example, there is a first segmented inspection area R1 that has been inspected, and a second segmented inspection area R2 that is currently located, and they are located relatively close to each other. An example of movement trajectory within areas R1 and R2 is shown by a dashed arrow. Assume that area R1 has been inspected and that at the present time, the system has reached the first optical adjustment execution point 1802 in area R2.

[0235] The set interval Δxp for optical adjustment locations in region R2 is, for example, the distance along the movement trajectory from location 1802 to location 1803. The set interval Δxq for optical adjustment necessity determination locations in region R2 is, for example, the distance along the movement trajectory from location 1802 to location 1804. In this example, Δxq = Δxp / 2 in the inspection recipe. Note that in this example, the interval Δxq is defined as the distance from the optical adjustment execution location to the optical adjustment necessity determination location, and not the interval between necessity determination locations.

[0236] The computer 201 calculates the distance Δx, which is the interval Δx from the last optical adjustment execution location 1801 in region R1 to the first optical adjustment execution location 1802 in the next region R2 (step S203). In this example, this distance Δx is the distance in the x direction. The inspection system determines that optical adjustment is unnecessary at a location if this distance Δx satisfies the condition Δx < Δxp / 2 (= Δxq) with respect to the interval Δxq for the optical adjustment necessity determination locations and the interval Δxp for the optical adjustment execution locations in region R2. In that case, the inspection system skips the optical adjustment even if the location is set as the optical adjustment execution location 1802 (step S208).

[0237] After the above skip, the inspection system also repositions the optical adjustment necessity determination point to a distance of, for example, Δxp / 2 from the last optical adjustment execution point 1801 in region R1, and slides the subsequent optical adjustment execution points and necessity determination points accordingly. Such additional processing is also effective.

[0238] After the above changes such as skipping, region R2 will be replaced with region R2b shown below. For example, optical adjustment execution location 1803 is relocated to optical adjustment execution location 1803b. Optical adjustment necessity determination location 1804 is relocated to optical adjustment necessity determination location 1804b.

[0239] On the other hand, if Δxq (=Δxp / 2) < Δx < Δxp, it is not necessarily required to perform optical adjustment at that location, but it is determined that an optical adjustment requirement determination is necessary, and the optical adjustment requirement determination is performed (step S207). In other words, such an initial optical adjustment execution location 1802 on the inspection recipe is changed to an optical adjustment requirement determination location depending on the result of the determination using the distance Δx.

[0240] In addition, this inspection system rearranges the optical adjustment execution points and optical adjustment necessity determination points along the movement trajectory to match the set intervals Δxp and Δxq relative to the initial point 1802. Such additional processing is also effective. If Δx > Δxp, the optical adjustment is performed according to the settings in the inspection recipe.

[0241] [Example of optical adjustment changes (2)] Figure 19 shows another specific example of the modification in Embodiment 2, where the interval Δx from the last optical adjustment execution point in the first divided inspection area to the first optical adjustment execution point in the next current divided inspection area is a constant time interval, independent of the position of each divided inspection area. Figure 19 shows that optical adjustments in the divided inspection areas from the present onward are appropriately skipped depending on the elapsed time since the previous optical adjustment execution point.

[0242] Here, the interval Δx = time interval Δt. In this example, there are multiple segmented inspection regions on the movement trajectory, namely regions R1, R2, R3, and R4. The time points t at the first optical adjustment points within each region are denoted as time points t1, t2, t3, and t4. In this example, Δt is assumed to be a constant time interval satisfying (t3 - t1) < Δt < (t4 - t1). The dashed arrows show an overview of movement between regions. Between the movement from region R3 to region R4, there is a time point corresponding to the time interval Δt from time point t1.

[0243] In this case, for example, at the point in the inspection recipe in region R2 where optical adjustment is scheduled to be performed (time t2), the time elapsed up to time t2 is less than Δt, so the optical adjustment is skipped (indicated by a dotted circle). Also, at the point in the inspection recipe in region R3 where optical adjustment is scheduled to be performed (time t3), the time elapsed up to time t3 is less than Δt, so either skipping or a determination of necessity (indicated by a dotted circle) is made. Also, at the point in the inspection recipe in region R4 where optical adjustment is scheduled to be performed (time t4), the time elapsed up to time t3 is greater than Δt, so the optical adjustment is performed as scheduled.

[0244] The above processing is effective in terms of throughput because the number of areas that can be skipped increases as the number of segmented inspection areas increases. Furthermore, although the above processing example shows the case where adjustments such as skipping are performed on the optical adjustment execution area using a fixed time interval Δt, the same processing example can be applied to the optical adjustment necessity determination area as well.

[0245] [Effects of Embodiment 2, etc.] As described above, according to the inspection system of Embodiment 2, it is possible to optimize the optical adjustment execution location and other elements even during inspection execution based on the inspection recipe that has been generated, thereby improving throughput and other factors.

[0246] [Modified version of Embodiment 2] The following is also possible as a modification of Embodiment 2. Figure 20 shows this modification. This modification has a configuration similar to the example of optimizing the arrangement of necessity determination points based on the test inspection described above. In this modification, similar to Embodiment 2, the content of the optical adjustment of the second divided inspection area from the present onward is changed based on the operation history of the optical adjustment of the first divided inspection area that has been inspected. In this modification, the spacing of the optical adjustment necessity determination points in the second divided inspection area is changed based on the history of the determination results of the optical adjustment necessity determination points in the first divided inspection area.

[0247] In the example in Figure 20, the left side shows the planned optical adjustment for the first segmented inspection area, region R1, and the history after the inspection, while the right side shows the planned optical adjustment for the current second segmented inspection area, region R2, and an example of the changed settings. First, in the planned area R1 in the upper left, there are, for example, two execution locations (black dots) and 10 necessity / non-necessity judgment locations (diamond dots). In the lower left, an example of the judgment result at each necessity / non-necessity judgment location in the result of the inspection is shown. Locations with black dots inside diamonds are locations where optical adjustment was performed because the judgment result was necessary, and locations with white dots inside diamonds are locations where the judgment result was negative and optical adjustment was omitted. For example, in region R1, optical adjustment was performed at 4 out of 10 necessity / non-necessity judgment locations.

[0248] On the other hand, the plan for the upper right region R2 is assumed to be the same as the plan for the upper left region R1. In this modified example, the optical adjustment necessity determination points in region R2 are changed and optimized based on the history of optical adjustment necessity determinations in the inspected region R1, in other words, the actual results. In the lower left region R1, the rate of optical adjustment execution based on the determination results was 4 / 10, so computer 201 adjusts the spacing, number, and density of the necessity determination points in region R2 to match that rate. Specifically, the number of necessity determination points in region R2 is reduced from the planned 10 to, for example, 4, as shown in the lower right.

[0249] According to the above modification, by changing the location for determining whether optical adjustment is necessary, the throughput for subsequent segmented inspection areas can be increased.

[0250] <Embodiment 3> The inspection system of Embodiment 3 will be explained using Figure 21. The inspection system of Embodiment 3 modifies and optimizes the optical adjustment operation conditions in the inspection recipe for the sample 7 to be inspected in a region, based on past inspection results of samples of the same semiconductor device and the same manufacturing process. The inspection results are information including optical adjustment operation history, including the results of the optical adjustment necessity determination, and are stored, for example, as inspection result data 252 in Figure 2. The inspection system of Embodiment 3 refers to the past inspection results information of samples of the same semiconductor device or the same manufacturing process for the target sample 7, and modifies the optical adjustment execution locations and necessity determination locations within the divided inspection regions for each group.

[0251] Embodiment 3 is similar to Embodiment 2 in that it modifies and optimizes the optical adjustment operation conditions of the divided inspection area by referring to history or performance information, but it differs in the following aspects. That is, while Embodiment 2 modifies the optical adjustment operation conditions on the movement trajectory of an inspection of a sample 7, Embodiment 3 modifies the optical adjustment operation conditions for the current sample 7 (e.g., a second wafer) using performance information from past area inspections of another sample (e.g., a first wafer).

[0252] For example, by performing the aforementioned test inspections, it is possible to some extent to optimize the placement and spacing of optical adjustment points and points for determining necessity before performing area inspections according to the inspection recipe. However, when using the same inspection recipe for multiple area inspections of multiple samples, the performance of the SEM100 and other equipment, as well as the surrounding environment, may change over time, potentially altering the inspection performance.

[0253] Therefore, it is effective to have a mechanism that can adjust and optimize the optical adjustment operating conditions of the inspection recipe even if there are some fluctuations in the equipment performance or surrounding environment, in other words, a mechanism that can absorb such fluctuations. Accordingly, the inspection system of Embodiment 3 modifies and optimizes the optical adjustment operating conditions for the area inspection of a target wafer 7 when a wafer 7 of the same semiconductor device (i.e., one with the same formation pattern, etc.) and manufactured using the same process has been subjected to area inspection in the past, using the performance information of that past area inspection.

[0254] For example, computer 202 stores in memory, as performance information for area inspection, area inspection performance information including optical adjustment operation history information for each wafer and for each area within the wafer. The performance information includes date and time information, sample information, manufacturing process information, information representing the applied inspection recipe, etc. The optical adjustment operation history information includes execution items and execution parameter values, as well as information on execution results and judgment results for optical adjustment execution locations and necessity / non-necessity judgment locations, and setting intervals. The optical adjustment operation history information may also include information such as necessity / non-necessity as a judgment result at necessity / non-necessity judgment locations within the divided inspection area, and the number of judgment results that were necessary or not necessary, and the percentage, relative to the number of necessity / non-necessity judgment locations within the divided inspection area.

[0255] The computer system 200 compares the number and percentage of wafers deemed necessary or unnecessary based on past inspection data (for example, from the first wafer to the Mth wafer), referencing historical data. For example, there may be changes in the number of wafers for which the necessity judgment result was deemed necessary, i.e., the number of wafers for which optical adjustment was actually performed. From the changes in historical data, it is possible to estimate whether the inspection performance has deteriorated. This inspection system calculates and understands such changes, compares them with a preset threshold, and if the change exceeds the threshold, rearranges and resets the optical adjustment execution locations and necessity judgment locations for the sample in question.

[0256] [Changes to optical adjustment operating conditions based on past performance] Figure 21 is an explanatory diagram of the function for changing and optimizing optical adjustment operating conditions based on past region inspection results in Embodiment 3. For example, the inspection recipe set in step S111 in Embodiment 1 is called Recipe A. Recipe A is a recipe for region inspection of wafer A (sample A) when manufacturing semiconductor device A by manufacturing process A, and includes the optical adjustment operating conditions described above.

[0257] In Figure 21, let's assume that on date and time 1, the inspection system performed a region inspection on sample A using recipe A (specifically A-1). After the inspection using recipe A, the inspection system saves information such as the settings for recipe A, the imaging and inspection results, and the operation history of SEM100 to inspection performance information 2101 (inspection result data 252 in Figure 2). Next, let's assume that on date and time 2, the inspection system performed a region inspection on the same sample A using the same recipe A (specifically A-2). Similarly, let's assume that the inspection system performed region inspections on the same sample A at each date and time (for example, date and time 1, 2, ..., 52), and the results are saved in inspection performance information 2101. A similar sample A is a wafer made from the same semiconductor device and the same manufacturing process.

[0258] This inspection system is designed to perform a region inspection on sample A (e.g., the Nth wafer) at the current date and time N. Region inspections of sample A (e.g., each wafer) using the same semiconductor device and manufacturing process have been performed on the same sample A from past dates and times 1 to 52, and these are stored as performance information 2101. The inspection recipe for the current region inspection of sample A is designated as recipe AN. Past recipes for sample A include recipes A-1 to A-52, which are basically the same in terms of optical adjustment operating conditions, but may differ for fine-tuning purposes.

[0259] This inspection system can extract past inspection results 2102 for the same recipe A (A-1 to A-52) for sample A from inspection performance information 2101. Looking at the information 2103 for recipe A-52 on date 52 of the inspection results 2102, for example, the recipe settings include the aforementioned optical adjustment execution items and execution parameter values, as well as information such as the optical adjustment execution locations and locations where necessity was determined. In addition, the operation history of the device during inspection includes information such as the number of optical adjustments performed, the locations and percentages where adjustments were performed, and the number of optical adjustment necessity determinations, the locations and percentages where determinations were made.

[0260] The computer 201 of this inspection system performs a modification process 2104 of the optical adjustment operating conditions in order to generate a recipe AN for the current area inspection of sample A, based on the past inspection results 2102 of sample A using the same recipe A. For example, if this inspection system were to look at the operation history of the device during the above inspection, suppose that the percentage of cases where optical adjustment was determined to be necessary at optical adjustment necessity determination points set at 500 μm intervals was 20% in the inspection of the first wafer (date and time 1), but became 0% in the inspection of the mth wafer (date and time m). This is an improvement in terms of the time required for optical adjustment.

[0261] In this case, the inspection system assumes that, for some reason, the change in inspection performance over time has decreased during the period from the 1st to the mth sheet. Based on this assumption, the inspection system modifies the interval between the optical adjustment necessity determination points in recipe AN to be wider. As a result, the number of points where optical adjustment necessity determination is performed can be reduced after the modification, and an improvement in throughput can be expected. The inspection system displays the optical adjustment operating conditions changed by the optical adjustment operating condition modification process 2004 on, for example, the GUI screen 2105. The user can check the optical adjustment operating conditions of recipe AN on the GUI screen 2105 and update the settings if the modified conditions are acceptable. The GUI screen 2105 may also display both the recipe before and after the modification for verification.

[0262] On the other hand, suppose that, for example, at optical adjustment necessity determination points set at 500 μm intervals, the percentage of wafers determined to require optical adjustment was 20% in the inspection of the first wafer (date and time 1), but increased to 50% in the inspection of the mth wafer (date and time m). This represents a deterioration in terms of the time required for optical adjustment. In this case, the inspection system considers that there has been a change in the equipment performance or surrounding environment during the period from wafer 1 to wafer m, resulting in a deterioration of inspection performance. Based on this consideration, the inspection system determines that optical adjustment needs to be performed at shorter intervals (distance or time). The inspection system changes the optical adjustment operation conditions in recipe AN, for example, by resetting the optical adjustment execution points and necessity determination points. For example, the optical adjustment execution points are changed from 1000 μm intervals to 500 μm intervals. Furthermore, the optical adjustment necessity determination points are changed from 500 μm intervals to 250 μm intervals. This prevents a decrease in inspection sensitivity during subsequent inspections.

[0263] On the other hand, in this case, shortening the interval and increasing sensitivity takes more time, sacrificing throughput. Furthermore, if the fluctuation range of the device performance is large, it may be necessary to perform maintenance on the device and surrounding environment rather than changing and optimizing the recipe settings as described above. For this reason, this inspection system may notify or warn the user via a GUI screen whether to change the inspection recipe or perform maintenance, allowing the user to select and decide each time. In addition, this inspection system may have two control modes: one that actually changes the optical adjustment operating conditions according to past performance as described above, and another that proposes and performs maintenance, and the user may be able to set in advance which mode to operate in.

[0264] [Effects of Embodiment 3, etc.] As described above, the inspection system of Embodiment 3 allows for the modification and optimization of the optical adjustment operating conditions for current and subsequent region inspections based on past region inspection results for sample 7. This makes it possible to maintain inspection sensitivity while, in some cases, improving throughput.

[0265] As described above, the present invention has been specifically described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist thereof. Except for the essential components, addition, deletion, replacement, etc. of the components are possible. Unless otherwise specified, each component may be singular or plural. Combinations of the embodiments are also possible.

Explanation of Reference Numerals

[0266] 1... electron source, 2... extraction electrode, 3... condenser lens, 4... primary electron beam, 5... deflector, 6... objective lens, 7... wafer (sample), 8... stage, 9... secondary electron, 10... secondary electron detector, 11... amplifier, 12... A / D converter, 13... main control unit, 14... arithmetic processing unit, 15... storage unit, 16... inspection processing unit, 17... display unit, 18... keyboard, 19... mouse, 20... spherical aberration corrector, 21... secondary electron aligner.

Claims

1. An inspection system for performing regional inspection of a sample, Charged particle beam device, A computer system connected to or built into the charged particle beam apparatus, Equipped with, The charged particle beam apparatus is A moving stage on which the aforementioned sample is mounted, A tuning device comprising an electron source that emits a beam, an electron optical system that adjusts the beam, and a detection system that detects particles emitted from the sample based on the beam, for irradiating the sample with a beam that is a charged particle beam, It has, The aforementioned computer system, For imaging at multiple inspection points in the inspection area irradiated by the beam that is the target of the area inspection of the sample, the operating conditions for optical adjustment using the adjustment device for the beam of the charged particle beam apparatus are determined. When determining the operating conditions for the optical adjustment, Based on the design layout information including information on the pattern formed on the sample, the inspection area is divided into segmented inspection areas belonging to groups according to the pattern classification. For each of the aforementioned groups, the optical adjustment items and their corresponding parameter values ​​are determined. Inspection system.

2. In the inspection system according to claim 1, When determining the operating conditions for the optical adjustment, the computer system determines, for each segmented inspection area, at least one of the locations on the movement trajectory for imaging where the optical adjustment will be performed and where the necessity of the optical adjustment will be determined. The execution locations are locations where the optical adjustment is always performed, and are determined to be fewer than the number of the multiple inspection points. The aforementioned necessity determination point is where the necessity of the optical adjustment is determined. If the determination result indicates that the adjustment is necessary, the optical adjustment is performed; otherwise, the adjustment is omitted. Inspection system.

3. In the inspection system according to claim 2, The computer system determines the spacing of the locations where the optical adjustment is performed within the divided inspection area according to the set sensitivity or throughput information. Inspection system.

4. In the inspection system according to claim 2, The computer system determines the spacing or number of locations for determining the necessity of optical adjustment in the divided inspection area according to the set sensitivity or throughput information. Inspection system.

5. In the inspection system according to claim 1, The optical adjustment execution items include, as candidates, at least one of the following: autofocus, automatic astigmatism correction, trajectory correction of secondary electrons or backscattered electrons, beam current value adjustment, axis center correction of the primary electron beam, and automatic brightness / contrast adjustment. Inspection system.

6. In the inspection system according to claim 1, The computer system displays the divided inspection area and the optical adjustment execution items and execution parameter values ​​for each group on a screen. Inspection system.

7. In the inspection system according to claim 2, The computer system displays on the screen at least one of the locations where optical adjustment is performed and the locations where necessity is determined for each of the divided inspection areas. Inspection system.

8. In the inspection system according to claim 2, The computer system, along the movement trajectory of the sample during the region inspection, modifies at least one of the execution location and the necessity determination location as the operation conditions for the optical adjustment of the target region from the present onward, based on the operation history of the optical adjustment of the inspected region. Inspection system.

9. In the inspection system according to claim 2, The computer system, when determining the operating conditions for the optical adjustment in the area inspection of the sample, modifies at least one of the execution location and the necessity determination location as the operating conditions for the optical adjustment based on past inspection results of samples that are the same semiconductor device or manufactured using the same process. Inspection system.

10. A computer system connected to or built into a charged particle beam apparatus for performing area inspection of a sample, The charged particle beam apparatus is A moving stage on which the aforementioned sample is mounted, A tuning device comprising an electron source that emits a beam, an electron optical system that adjusts the beam, and a detection system that detects particles emitted from the sample based on the beam, for irradiating the sample with a beam that is a charged particle beam, It has, The aforementioned computer system, For imaging at multiple inspection points in the inspection area irradiated by the beam that is the target of the area inspection of the sample, the operating conditions for optical adjustment using the adjustment device for the beam of the charged particle beam apparatus are determined. When determining the operating conditions for the optical adjustment, Based on the design layout information including information on the pattern formed on the sample, the inspection area is divided into segmented inspection areas belonging to groups according to the pattern classification. For each of the aforementioned groups, the optical adjustment items and their corresponding parameter values ​​are determined. Computer system.

11. A computer program that causes a computer system connected to or built into a charged particle beam apparatus to perform processing for inspecting a sample area, The charged particle beam apparatus is A moving stage on which the aforementioned sample is mounted, A tuning device comprising an electron source that emits a beam, an electron optical system that adjusts the beam, and a detection system that detects particles emitted from the sample based on the beam, for irradiating the sample with a beam that is a charged particle beam, It has, Regarding imaging at multiple inspection points in the inspection area irradiated by the beam that is the target of the area inspection of the sample, the computer system is made to perform a process to determine the operating conditions for optical adjustment using the adjustment device for the beam of the charged particle beam apparatus. The process for determining the operating conditions of the optical adjustment is as follows: Based on design layout information including information on the pattern formed on the sample, the inspection area is divided into segmented inspection areas belonging to groups according to the pattern classification. The process includes determining the optical adjustment execution items and execution parameter values ​​for each of the divided inspection areas. Computer program.

Images