Charged particle beam device management system and charged particle beam device management method

Abstract

Provided are a charged particle beam device management system and a charged particle beam device management method which are capable of achieving, in reducing a machine difference, optimal and planned device management according to the situation of a manufacturing site.　This charged particle beam device management system has at least one charged particle beam device and a device management device. The device management device comprises: an electron optical system simulation unit that obtains each of the states of a device to be evaluated and a target device that are the charged particle beam device; a device state correction candidate calculation unit that obtains a correction condition of a device component such that the device to be evaluated approaches the state of the target device; and a device state estimation unit that obtains a difference from the target device when the device to be evaluated is corrected in accordance with the correction condition. The device state correction candidate calculation unit obtains a cost when executing the correction on the device and outputs the difference between the obtained correction condition and the corrected target device and the correction cost.

Description

Charged particle beam device management system and charged particle beam device management method

[0001] The present invention relates to a charged particle beam device management system and a charged particle beam device management method.

[0002] A technique described in Patent Document 1 is known as background art in this technical field. Patent Document 1 describes a system for managing inter-instrument differences and inter-instrument differences due to changes over time in a scanning electron microscope apparatus, the system including a measurement unit that measures inter-instrument differences and inter-instrument differences due to changes over time based on secondary electron image data obtained by imaging a standard wafer and substantially simultaneously measures index values ​​indicating various apparatus conditions, an apparatus difference factor analysis unit that analyzes the relationship between the inter-instrument differences measured by the measurement unit and the index values ​​indicating the various apparatus conditions to estimate the causes of the inter-instrument differences, and an output unit that displays and outputs the causes of the inter-instrument differences estimated by the apparatus difference factor analysis unit. The patent document also discloses that the system includes a database that stores in advance the relationship between potential causes of the inter-instrument differences and apparatus control parameters necessary to adjust the causes of the inter-instrument differences, and an apparatus control unit that selects appropriate apparatus control parameters from the relationships stored in the database in accordance with the causes of the inter-instrument differences output by the output unit, and automatically adjusts the selected apparatus control parameters appropriately between the apparatuses to reduce the inter-instrument differences.

[0003] Patent No. 4638800

[0004] Patent Document 1 describes a system for managing machine differences in scanning electron microscopes, which selects appropriate machine control parameters based on the causes of machine differences and automatically adjusts the selected machine control parameters appropriately to reduce machine differences between the machines. However, the processing method of Patent Document 1 does not take into account that appropriate machine control parameters vary depending on the object being measured, and there is a risk that machine differences cannot be reduced for objects being measured that are different from standard wafers. Furthermore, as an essential solution to this problem, mechanical adjustments such as part replacement may be required in addition to adjusting the machine control parameters, but this may result in problems such as extended machine downtime.

[0005] Therefore, the present invention provides a charged particle beam equipment management system and a method for managing a charged particle beam equipment that can realize optimal and planned equipment management according to the situation at the manufacturing site while reducing machine differences.

[0006] In order to solve the above problems, the charged particle beam device management system of the present invention is a charged particle beam device management system having at least one charged particle beam device and a device management device, wherein the device management device comprises an electron optical system simulation unit that calculates the state of the device to be evaluated, which is a charged particle beam device, and a target device, respectively, an device state correction candidate calculation unit that calculates correction conditions for device components so that the device to be evaluated approaches the state of the target device, and an device state estimation unit that calculates the difference between the target device when the device to be evaluated is corrected in accordance with the correction conditions, and wherein the device state correction candidate calculation unit calculates the cost of performing correction on the device, and outputs the difference between the calculated correction conditions and the target device after correction, as well as the correction cost.

[0007] In addition, the method for managing a charged particle beam device according to the present invention is a method for managing a charged particle beam device in a charged particle beam device management system having at least one charged particle beam device and a device management device, wherein an electron optical system simulation unit constituting the device management device respectively determines the states of an evaluation target device, which is a charged particle beam device, and a target device, an device state correction candidate calculation unit constituting the device management device determines correction conditions for device components so that the evaluation target device approaches the state of the target device, an device state estimation unit constituting the device management device determines the difference between the evaluation target device and the target device when the evaluation target device is corrected in accordance with the correction conditions, and the device state correction candidate calculation unit determines the cost of performing the correction on the device, and outputs the difference between the determined correction conditions and the target device after correction, as well as the correction cost.

[0008] According to the present invention, it is possible to provide a charged particle beam device management system and a charged particle beam device management method that can realize optimal and planned device management according to the situation at the manufacturing site in order to reduce machine differences. Problems, configurations, and effects other than those described above will become clear from the description of the following embodiments.

[0009] 9 is a diagram showing a schematic configuration of a charged particle beam device management system according to a first embodiment of the present invention. FIG. 10 is a diagram showing the configuration of each individual scanning electron microscope device shown in FIG. 1. FIG. 11 is a diagram showing the configuration of the device management device shown in FIG. 1. FIG. 12 is a flowchart showing the overall sequence of a process for estimating a device state. FIG. 4 is a diagram showing an example of a captured image acquired in the process for estimating a device state shown in FIG. 4. FIG. 4 is a flowchart showing a detailed sequence for evaluating the validity of an estimation result in the process for estimating a device state shown in FIG. 4. FIG. 6 is a diagram showing an example of evaluating the validity of the estimation result shown in FIG. 6. FIG. 6 is a diagram showing an example of evaluating the validity of the estimation result shown in FIG.

[0010] In this specification, the term "charged particle beam device" refers to, for example, a scanning electron microscope (SEM), a critical dimension scanning electron microscope (CD-SEM) that measures the dimensions of a pattern from an image, a defect review SEM (Defect Review-SEM) that is a scanning electron microscope device that inspects images for abnormalities or defects such as foreign matter or pattern deformation, and a focused ion beam (FIB) device. In this specification, a scanning electron microscope (SEM) will be described as an example of a charged particle beam device. In addition, a system for managing a scanning electron microscope device is called a charged particle beam device management system.

[0011] The present invention aims to reduce the difference in measurement dimensions between scanning electron microscopes, which are an example of charged particle beam devices, in a scanning electron microscope system including multiple scanning electron microscopes that measure the dimensions of a micropattern from an image obtained by capturing the pattern. Alternatively, the present invention aims to reduce the difference in measurement dimensions between the same device due to changes over time in factors other than the object being imaged, such as the device and the environment. In this embodiment, the difference in measurement dimensions between the devices will be referred to as the measurement value instrument difference.

[0012] In the charged particle beam device management system of this embodiment, the states of the device to be evaluated and the target device are respectively determined, correction conditions for the device components are determined so that the device to be evaluated approaches the state of the target device, the difference between the device to be evaluated and the target device when corrected according to the correction conditions is determined, the cost of performing the correction on the device is determined, and the determined correction conditions, the difference from the target device after correction, and the correction cost are output.

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all drawings for explaining the embodiments of the present invention, elements having the same function (similar components) are designated by the same reference numerals, and duplicate explanations will be omitted as a general rule. However, the present invention should not be interpreted as being limited to the description of the embodiments shown below. Those skilled in the art will readily understand that the specific configuration can be changed within the scope of the idea or intent of the present invention.

[0014] In this embodiment, a charged particle beam device management system will be described, which is a device management system including a scanning electron microscope device that can present a device adjustment method for reducing the device difference in measurement values ​​using the above-described embodiment.

[0015] [System Configuration] Fig. 1 is a diagram showing a schematic configuration of a charged particle beam device management system according to Example 1 of the present invention. As shown in Fig. 1, the charged particle beam device management system 1 is broadly composed of a plurality of scanning electron microscope devices 10 and a device management device 11 that manages these scanning electron microscope devices 10, and the scanning electron microscope devices 10 and the device management device 11 are connected via a data bus or a network 12.

[0016] Fig. 2 is a diagram showing the configuration of each individual scanning electron microscope apparatus shown in Fig. 1. As shown in Fig. 2, the scanning electron microscope apparatus 10 broadly comprises an electron optical system 201 for acquiring electron beam images, and an information processing system 202 for processing these images to measure the target pattern.

[0017] The electron optical system 201 that constitutes the scanning electron microscope apparatus 10 mainly comprises a stage 204 on which a sample 203 is mounted, an electron gun 206 that emits an electron beam 205, an aperture 207 that focuses the electron beam 205, a deflection lens 208 that deflects the electron beam 205, an objective lens 209 that adjusts the focal position of the electron beam 205, a retarding electrode 210, a booster 211 that pulls up scattered electrons generated by irradiation of the electron beam 205 onto the sample 203, an electron detector 212 that has the function of converting the scattered electrons into an electric signal, a photomultiplier tube 213 that arbitrarily amplifies the intensity of the detected electric signal, and an A / D converter 214 that converts the amplified electric signal into a digital signal, and the stage 204, the electron gun 206 to the photomultiplier tube 213 are controlled by a control unit 215.

[0018] Meanwhile, the main components of the information processing system 202 constituting the scanning electron microscope apparatus 10, which measures an image pattern from scattered electron data detected by the electron detector 212 and converted into a digital signal, are an image generation unit 216 that creates image data from the scattered electron data, a dimension measurement unit 217 that calculates pattern dimensions from the image data, a memory unit 218 that stores various data such as image data and measured dimensions, and an input / output unit 219 that has a function (GUI function) for allowing a user to input imaging conditions and dimension measurement parameters and output the obtained results. The image generation unit 216, dimension measurement unit 217, memory unit 218, and input / output unit 219 transmit and receive data to and from each other via a data bus or the Internet 12. The image generation unit 216 and dimension measurement unit 217 are realized by, for example, a processor such as a CPU (not shown), a ROM that stores various programs, a RAM that temporarily stores data in the calculation process, and a storage device such as an external storage device, and the processor such as the CPU reads and executes the various programs stored in the ROM and stores the execution results in the RAM, the external storage device, or cloud storage via a network connection. In addition, data can be sent and received to and from other scanning electron microscope apparatuses 10 and apparatus management apparatuses 11 via this data bus or the Internet 12 .

[0019] 3 is a diagram showing the configuration of the device management device shown in FIG. 3. As shown in FIG. 3, the device management device 11 mainly comprises a processing unit 301, a storage unit 302, and an input / output unit 303. The processing unit 301 receives the configuration of the electron optical system 201 and the imaging conditions controlled by the control unit 215 as input, and calculates the electromagnetic field distribution formed by each element constituting the electron optical system 201 using the Finite Difference Time Domain (FDTD) method or the Finite Element Method (FEM) method. the electron-optical system simulation unit 301a, which calculates the state of the electron beam 205 by calculating the trajectories of electrons emitted from the electron gun 206 in the calculated electromagnetic field distribution, and further calculates the trajectories of scattered electrons generated from the surface of the sample 203 to calculate the detection conditions; an apparatus state estimation unit 301b which determines the configuration conditions of the electron-optical system 201 so as to reproduce the state of each scanning electron microscope apparatus 10 in the electron-optical system simulation; an apparatus state correction candidate calculation unit 301c which determines the correction content of the configuration of the electron-optical system 201 so as to bring the apparatus state under the estimated configuration conditions of the electron-optical system 201 closer to the target apparatus state; and an imaging control unit 301d which controls the acquisition of images by the scanning electron microscope apparatus 10. Here, the electron-optical system simulation unit 301 a, the apparatus state estimation unit 301 b, the apparatus state estimation unit 301 b, and the imaging control unit 301 d are realized by, for example, a processor such as a CPU (not shown), a ROM for storing various programs, a RAM for temporarily storing data in the calculation process, and a storage device such as an external storage device, and the processor such as the CPU reads and executes the various programs stored in the ROM and stores the calculation results, which are the execution results, in the RAM, the external storage device, or cloud storage via a network connection, etc. The storage unit 302 is composed of a simulation condition storage unit 302 a for storing configuration conditions of the electron-optical system 201 to be input to the electron-optical system simulation unit 301 a, a target condition storage unit 302 b for storing target configuration conditions of the electron-optical system 201, a correction effect storage unit 302 c for storing candidates for correction contents for the configuration of the electron-optical system 201, the correction effects and costs, and an imaging condition storage unit 302 d for storing imaging conditions for acquiring an image with the scanning electron microscope apparatus 10.

[0020] [Apparatus State Estimation Method] This embodiment aims to reduce differences in measurement dimensions between apparatuses, i.e., inter-apparatus measurement discrepancies. The direct cause of inter-apparatus measurement discrepancies is differences in the images captured between the apparatuses. Image differences arise from differences in the state of the electron beam 205 irradiating the sample 203 to be imaged or differences in the detection conditions for scattered electrons generated by the electron beam 205 irradiating the sample 203 to be imaged. These differences in the state of the electron beam 205 and the detection conditions for scattered electrons arise from differences in the electromagnetic field distribution of the electron optical system 201. Differences in the electromagnetic field distribution arise from differences in the properties, arrangement, and control values ​​of the components constituting the electron optical system 201. Some component properties are difficult to measure. Furthermore, there is no method for visualizing or directly measuring the state of the electron beam 205, the detection conditions for scattered electrons, or the electromagnetic field distribution of the electron optical system 201 on an actual apparatus, making it difficult to grasp the state of each apparatus. Therefore, the state of the scanning electron microscope apparatus 10 is estimated using images, which are representative outputs of the apparatus, and electron optical system simulation. A simulation is performed by changing the configuration conditions of the electron optical system 201, and the configuration conditions when the output of the simulation matches the output of the scanning electron microscope apparatus 10 to be estimated are estimated as the apparatus state of the apparatus to be estimated. Here, the configuration conditions correspond to, for example, the arrangement of the electron optical system 201, that is, the arrangement of a stage 204 on which a sample 203 is mounted, an electron gun 206 that emits an electron beam 205, an aperture 207 that focuses the electron beam 205, a deflection lens 208 that deflects the electron beam 205, an objective lens 209 that adjusts the focal position of the electron beam 205, a retarding electrode 210, a booster 211 that pulls up scattered electrons generated by irradiation of the electron beam 205 onto the sample 203, an electron detector 212 that has the function of converting the scattered electrons into an electric signal, a photomultiplier tube 213 that arbitrarily amplifies the intensity of the detected electric signal, and an A / D converter 214 that converts the amplified electric signal into a digital signal.

[0021] 4 is a flowchart showing the overall sequence of processing for estimating the apparatus state of the scanning electron microscope apparatus 10. In this embodiment, an example of processing results is shown assuming that the difference between the scanning electron microscope apparatus 10 for which the apparatus state is to be estimated and the target scanning electron microscope apparatus 10 is the diameter of the aperture 207 that narrows down the electron beam 205, which is one of the main components of the electron optical system 201 shown in FIG.

[0022] As shown in FIG. 4 , the overall sequence begins by setting a plurality of imaging conditions necessary for estimating the device state (step S402). The plurality of imaging conditions set in step S402 are selected in advance as conditions suitable for estimating the device state, stored in the imaging condition storage unit 302d of the device management device 11, and then read out in step S402. Here, selecting a condition suitable for estimating the device state means, for example, selecting a condition with a different focal height. Alternatively, the condition may be input each time via the input / output unit 303 of the device management device 11. In this embodiment, five conditions with different focal heights of the electron beam 205 are set as the plurality of imaging conditions. In other words, this means adjusting the focal height by the configuration (applied voltage) of the objective lens 209.

[0023] Next, in step S403, the imaging control unit 301d ( FIG. 3 ), which constitutes the device management device 11, acquires images under multiple imaging conditions set in the scanning electron microscope device 10 to be estimated. In this embodiment, a calibration sample is assumed to be an imaged object, a pattern of randomly arranged holes, which is often used to evaluate the diameter and aberration of the electron beam 205. In other words, a pattern close to the dimensions that the device user typically wants to measure is assumed. FIG. 5 shows an example of an imaged image 501 acquired in the process of estimating the device state shown in FIG. 4. Note that FIG. 5 exaggerates the blurring for ease of understanding. A focal height of zero represents a condition in which the focal plane of the electron beam 205 is located on the surface of the sample 203 to be imaged. The imaged image 501 is sharpest when the focal height is near zero. As the focal height moves away from zero, both positive and negative, the diameter of the electron beam 205 irradiated on the surface of the sample 203 to be imaged increases, resulting in a blurred image 501.

[0024] Returning to the processing sequence of FIG. 4 , a simulation calculation of the electron-optical system 201 is performed in parallel with imaging. First, in step S404, the apparatus state estimation unit 301b ( FIG. 3 ) constituting the apparatus management apparatus 11 sets the configuration conditions of the electron-optical system 201 required for the simulation. The configuration conditions are stored in advance in the simulation condition storage unit 302a of the apparatus management apparatus 11, and are read out by the apparatus state estimation unit 301b ( FIG. 3 ) in step S404. Alternatively, the configuration conditions may be input each time via the input / output unit 303 ( FIG. 3 ) of the apparatus management apparatus 11. In this embodiment, conditions are set for multiple components, including the aperture 207 that narrows down the electron beam 205, among the main components of the electron-optical system 201 shown in FIG. 1 . For the aperture 207, the configuration conditions include the hole diameter. Furthermore, in this embodiment, the initial conditions to be set are the configuration conditions of the electron-optical system 201 in the target scanning electron microscope apparatus 10.

[0025] Next, in step S405, the electron-optical system simulation unit 301a ( FIG. 3 ) constituting the device management device 11 simulates the electromagnetic field distribution of the electron-optical system 201, the state of the electron beam 205 formed thereby, and the detection conditions for scattered electrons under the multiple imaging conditions set in step S402. In the simulation, the electromagnetic field distribution generated in the electron-optical system 201 is simulated according to the configuration conditions of the components of the electron-optical system 201 that affect the electromagnetic field distribution, namely, the deflection lens 208 that deflects the electron beam 205, the objective lens 209 that adjusts the focal position of the electron beam 205, the retarding electrode 210, and the booster 211 that pulls up scattered electrons generated by irradiation of the electron beam 205 onto the sample 203. Here, the trajectory of electrons emitted from the electron gun 206, one of the components of the electron-optical system 201, is calculated, and the state of the electron beam 205 irradiated onto the sample 203, which is the imaging target, is calculated. The state of the electron beam 205 affects the captured image 501, and is specifically expressed by indices such as the beam diameter, aperture angle, tilt angle, and aberration coefficient. In addition, the trajectories of scattered electrons generated by irradiation of the electron beam 205 onto the sample 203 are calculated, and the state of the electrons detected after reaching the electron detector 212 is calculated. The state of the detected electrons affects the captured image 501, and is specifically expressed by indices such as the energy range and scattering angle range of the detected electrons.

[0026] Next, in step S406, the device state estimation unit 301b constituting the device management device 11 evaluates the degree of agreement between the state of the scanning electron microscope device 10 to be estimated and the result calculated in step S405, and evaluates the validity of the calculation result. As described above, there is no method for visualizing or directly measuring the electromagnetic field distribution of the electron optical system 201 in the scanning electron microscope device 10, the state of the electron beam 205, or the state of the detected electrons, so how to evaluate them is an issue. In this embodiment, the validity of the calculation result obtained in step S405 is evaluated by comparing it with the captured image 501 acquired in step S403.

[0027] Fig. 6 is a flowchart showing a detailed sequence for evaluating the validity of the estimation result in the device state estimation process shown in Fig. 4. That is, this is an example of a detailed processing sequence of step 406. As shown in Fig. 6, first, the imaging control unit 301d constituting the device management device 11 reads (step S602) images 501 captured under the multiple imaging conditions acquired in step S403 (Fig. 4). An example of the read captured images 501 is as shown in Fig. 5.

[0028] Next, in step S603, the device state estimation unit 301b constituting the device management device 11 reads the state of the electron beam 205 calculated in step S405 ( FIG. 4 ). In FIG. 7 , among the indicators representing the state of the electron beam 205, the diameter of the electron beam 205 is plotted as a hollow circle 701. As described above, the configuration conditions of the electron optical system 201 set during calculation are the configuration conditions of the target scanning electron microscope apparatus 10. Therefore, it can be said that the plot 701 in FIG. 7 represents the diameter of the electron beam 205 in the target scanning electron microscope apparatus 10. The diameter of the electron beam 205 is smallest at a focal height of zero and increases as the focal height moves away from zero. Furthermore, the tendency for the diameter to increase is generally different between the upper and lower portions of the beam (positive and negative focal heights).

[0029] Returning to the explanation of FIG. 6 , next, the device state estimation unit 301b constituting the device management device 11 learns the relationship between the calculated diameter 701 of the electron beam 205 (state of the electron beam 205) illustrated in FIG. 7 and the captured image 501 illustrated in FIG. 5 (step S604). In this embodiment, deep learning is applied as the learning method. The learning method is not limited to this, and the diameter (state) of the electron beam 204 and the captured image 501 may each be converted into feature quantities, and the relationship between them may be determined by machine learning other than deep learning. Alternatively, the relationship may be determined by regression analysis of a predetermined function.

[0030] Next, in step S605, the device state estimation unit 301b constituting the device management device 11 estimates the state of the electron beam 205 from the captured image 501 using a deep learning network obtained by learning, which estimates the state of the electron beam 205 from the captured image 501. Here, in FIG. 7 , an example of an estimation result 702 of the beam diameter, which is one of the states of the electron beam 205, is shown superimposed with a star. For ease of explanation, the beam diameter 703 assumed in the scanning electron microscope apparatus 10 being estimated is also shown superimposed with a hollow triangle. As described above, it is assumed that there is a difference in the hole diameter of the aperture 207 between the scanning electron microscope apparatus 10 being estimated and the target scanning electron microscope apparatus 10. If the calculated electron beam state can reproduce the scanning electron microscope apparatus 10 being estimated, the change tendency of the electron beam state between the imaging conditions will be the same. That is, learning the relationship between the calculated electron beam diameter 701 and the captured image 501 eliminates the learning error in principle. Therefore, when the electron beam diameter is re-estimated for the captured image 501 (self-verification), the calculated electron beam diameter 701 and the result (electron beam diameter) 702 estimated based on the learning results match. Conversely, if the calculated electron beam diameter 701 does not reproduce the image of the scanning electron microscope device 10, learning the relationship between the calculated electron beam diameter 701 and the captured image 501 increases the learning error in principle. Therefore, when the electron beam diameter is re-estimated for the captured image 501 (self-verification), the difference between the calculated electron beam diameter 701 and the result (electron beam diameter) 702 estimated based on the learning results increases. Therefore, finally, the device status estimation unit 301b constituting the device management device 11 calculates the difference between the calculated electron beam diameter 701 and the electron beam diameter 702 estimated based on the learning results (step S606). Then, the process ends (step S607). The difference value is used as a value for evaluating the validity of the calculated electron beam diameter 701 .

[0031] In this embodiment, a method has been described for evaluating the difference between the state (diameter) of the electron beam 205 calculated by simulation using a learning error and the state (diameter) of the electron beam 205 in the scanning electron microscope device 10 that has been imaged. However, instead of learning, the state of the electron beam 205 in the scanning electron microscope device 10 may be estimated using a pre-designed estimation function, and the difference from the calculated state of the electron beam 205 may be calculated.

[0032] Returning to the description of FIG. 4 , in step S407, the device state estimation unit 301b constituting the device management device 11 determines whether the validity satisfies the requirements. Specifically, it determines whether the difference between the calculated electron beam state (electron beam diameter) 701 calculated in step S605 ( FIG. 6 ) and the electron beam diameter 702 estimated based on the learning results is greater than or smaller than a reference value. The difference may be evaluated based on the average value of the differences under multiple imaging conditions, or the maximum value of the differences. If the requirements are not satisfied, the device state estimation unit 301b constituting the device management device 11 changes the configuration conditions of the electron-optical system 201 set in the simulation (step S408), and repeats steps S405 to S407 until it is determined in step S407 that the calculated electron beam state (diameter) 701 is valid. FIG. 8 shows an example of the beam diameter estimation result after changing the configuration conditions, indicated by a star 702 (electron beam diameter 702 estimated based on the learning results). 8 shows the results when the hole diameter of the aperture 207, one of the configuration conditions of the electron optical system 201, is changed, and is an example of the results in which the calculated electron beam state (diameter) 701 in step S407 (FIG. 4) is determined to be appropriate. As in FIG. 7, the calculated beam diameter (open circle 701) and the beam diameter (triangle 703) assumed in the scanning electron microscope apparatus 10 for estimating the apparatus state are also shown superimposed. It can be seen that all the results are generally consistent.

[0033] If the requirements are met in step S407, the simulation condition storage unit 302a constituting the device management device 11 stores the configuration conditions of the electron-optical system 201 set in the simulation, the state of the electron beam 205 at this time, and the detection conditions of scattered electrons as the state of the scanning electron microscope device 10 to be estimated (step S409). The post-storage process is terminated (step S410). In addition to this embodiment, a comprehensive simulation may be performed over a range of assumed configuration conditions of the electron-optical system 201, and the conditions that minimize the result of step S407 may be selected.

[0034] Through the processing up to this point, the configuration conditions of the scanning electron microscope apparatus 10 to be estimated, the state of the electron beam 205 at that time, and the detection conditions for scattered electrons are grasped. Specifically, it was estimated that the hole diameter of the aperture 207 is different from that of the target scanning electron microscope apparatus 10.

[0035] [Presentation of Candidate Apparatus State Adjustment Methods and the Effects and Costs of Each Candidate] In the above-described apparatus state estimation method, it is estimated that the hole diameter of the aperture 207 in the estimation target scanning electron microscope apparatus 10 is different from that of the target scanning electron microscope apparatus 10. In this case, to bring the estimation target apparatus closer to the target apparatus, it is conceivable to select an aperture 207 with the same hole diameter and replace the aperture 207. However, the aperture replacement operation requires the apparatus to be stopped for several hours to several tens of hours, and therefore, if possible, another method would be preferable. In other words, it is desirable to select an adjustment method that takes into account not only the effect of equalizing the differences between apparatuses but also the cost required for adjustment. Therefore, in this embodiment, the effect of reducing the differences between apparatuses when adjusting components other than the aperture 207 and the cost required for adjustment are output together, allowing the user to select an adjustment method.

[0036] 9 is a flowchart showing the overall sequence of processing for outputting adjustment technique candidates for bringing the apparatus state of the scanning electron microscope apparatus 10 that is the estimation target closer to that of the target scanning electron microscope apparatus 10. As shown in FIG. 9, the apparatus state correction candidate calculation unit 301c that constitutes the apparatus management apparatus 11 first sets the configuration conditions of the electron-optical system 201 in the target scanning electron microscope apparatus 10 (step 902). The configuration conditions of the electron-optical system 201 in the target scanning electron microscope apparatus 10 are stored in advance in the target condition storage unit 302b of the apparatus management apparatus 11 and are read out in step 902. Alternatively, they may be input each time via the input / output unit 303 of the apparatus management apparatus 11.

[0037] Next, the apparatus status correction candidate calculation unit 301c constituting the apparatus management device 11 calculates the electromagnetic field distribution of the electron optical system 201, the state of the electron beam 205 formed thereby, and the scattered electron detection conditions by electron optical system simulation (step S903). Specifically, the process is the same as step S405 in FIG. 4 . Similarly, the apparatus status correction candidate calculation unit 301c constituting the apparatus management device 11 sets the pre-adjustment, i.e., current, configuration conditions of the electron optical system 201 in the scanning electron microscope apparatus 10 to be estimated (step 904). Specifically, the configuration conditions of the scanning electron microscope apparatus 10 to be estimated, which were stored in the storage unit 302a of the apparatus management device 11 in step S408 in FIG. 4 , are read. In this embodiment, the hole diameter of the aperture 207 is set under conditions different from those of the target apparatus. Next, the apparatus status correction candidate calculation unit 301c constituting the apparatus management device 11 calculates the electromagnetic field distribution of the electron optical system 201, the state of the electron beam 205 formed thereby, and the scattered electron detection conditions by electron optical system simulation (step S905). Specifically, the process is the same as that in step S405 in Fig. 4. When the configuration conditions of the electron optical system in the scanning electron microscope apparatus 10 that is the current estimation target are set in step S904, the same result as that in Fig. 8 is obtained for the beam diameter of the electron beam 205.

[0038] Next, in step S906, the apparatus state correction candidate calculation unit 301c constituting the apparatus management apparatus 11 calculates the differences in the state of the electron beam 205 and the scattered electron detection conditions between the target scanning electron microscope apparatus 10 and the estimation target scanning electron microscope apparatus 10, and saves the results (saving the differences after apparatus adjustment). In practice, it is desirable to be able to grasp the magnitude of the instrumental difference in measurement values, which is the objective of this process, from this information. These relationships may be formulated in advance, and the magnitude of the instrumental difference in measurement values ​​may be calculated based on this.

[0039] Next, in step S907, the device status correction candidate calculation unit 301c constituting the device management device 11 determines whether the change in the configuration conditions of the electron-optical system 201 before adjustment in the scanning electron microscope device 10 that is the estimation target is sufficient, and if it is not sufficient, the configuration conditions of the electron-optical system 201 in the scanning electron microscope device 10 that is the estimation target are changed (step S908). Of the configuration conditions, changes are also made to conditions other than those of the parts for which there is a difference in configuration conditions between the target device and the estimation target device. In this embodiment, it is estimated that the hole diameters of the aperture 207 are different, and the control parameters are changed assuming a change in the lens magnification of the objective lens 209.

[0040] In step S909, when the configuration conditions are changed, the apparatus status correction candidate calculation unit 301c constituting the apparatus management apparatus 11 calculates the cost for adjusting the scanning electron microscope apparatus 10 to the changed configuration conditions and saves the result (saving the cost of apparatus adjustment). The calculated cost includes not only service costs related to parts purchases and work, but also apparatus downtime, associated delays in manufacturing the inspected product, or the risk of manufacturing defects due to skipped evaluation. After the configuration conditions are changed, the processes from step S905 to step S909 are repeated.

[0041] In this embodiment, it is assumed that the difference between the estimated device and the target device is the hole diameter of the aperture 207. As an example of changing configuration conditions other than the aperture 207, FIG. 10 shows the beam diameter (calculated electron beam diameter 704) when changing the parameters controlling the lens magnification of the objective lens 209. The open circles plot the beam diameter 701 in the target device, and the open triangles plot the beam diameter 703 in the estimated device before adjustment. The beam diameter 704 after adjusting the objective lens 209 approaches the beam diameter 701 in the target device near a focal height of zero. In this case, for a measurement target with a high step, the beam diameter deviates from the target device depending on the height at which the electron beam 205 is irradiated. However, for a measurement target including a step within a range of focal height minus b or plus c, for example, it is expected that the correction effect is sufficient compared to before adjustment.

[0042] 9, if the change in the configuration conditions is sufficient in step S907, the device status correction candidate calculation unit 301c constituting the device management device 11 outputs the difference (adjustment effect) between the calculated configuration conditions and the target device under each configuration condition as change candidates for the configuration conditions (step S910), and then terminates the process (step S911).

[0043] Examples of input / output GUIs are shown in Figures 11 and 12. Figure 11 is an example of a GUI 1100 that starts the processing flow shown in Figures 4 and 9, and includes an input unit 1101 for selecting or inputting a target device for which the device state is to be estimated, an input unit 1102 for selecting or inputting a target device state, and an input unit 1103 for instructing the start of evaluation. Figure 12 is an example of an output unit 1200 for outputting the estimation results of the device state and adjustment candidates, and includes a difference display unit 1201 that displays the difference between the configuration conditions of the target device and the estimation target device, and an adjustment candidate list unit 1202 that displays, for each adjustment item, the work content and adjustment effect (in this embodiment, the difference in measured values ​​after adjustment), constraints on the adjustment effect, the time required for the work, costs, etc.

[0044] The above process allows for the selection of adjustments that take into account the effect and cost of equipment adjustments. Based on this result, it is expected that manufacturing efficiency will be improved by reviewing not only equipment adjustment plans but also inspection equipment operation plans.

[0045] As described above, according to this embodiment, it is possible to provide a charged particle beam device management system and a charged particle beam device management method that can realize optimal and planned device management according to the situation at the manufacturing site in order to reduce machine differences.

[0046] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment.

[0047] 1...Charged particle beam device management system, 10...Scanning electron microscope device, 11...Device management device, 12...Data bus or network, 201...Electron optical system of scanning electron microscope device, 202...Information processing system of scanning electron microscope device, 203...Sample, 204...Stage, 205...Electron beam, 206...Electron gun, 207...Aperture, 208...Deflection lens, 209...Objective lens, 210...Retarding electrode, 211...Booster, 212...Electron detector, 213...Photomultiplier tube, 214...A / D converter, 215...Control unit of scanning electron microscope device, 216...Image generation unit, 217...Dimension measurement unit, 218...Memory unit of scanning electron microscope device, 219...Input / output unit of scanning electron microscope device, 301...Processing unit of device management device, 301a...Electron optical system simulation unit, 301b...Device state estimation unit, 301c... Device state correction candidate calculation unit, 301d...imaging control unit, 302...storage unit of device management device, 302a...simulation condition storage unit, 302b...target condition storage unit, 302c...correction effect storage unit, 302d...imaging condition storage unit, 303...input / output unit of device management device, 501...captured image, 701, 704...calculated electron beam diameter, 702...electron beam diameter estimated based on learning results, 703...expected electron beam diameter, 1100...example GUI at start of processing flow, 1101...input unit for selecting or inputting target device for device state estimation, 1102...input unit for selecting or inputting target device, 1103...input unit for instructing start of evaluation, 1200...output unit for device state estimation result and adjustment candidate, 1201...unit for displaying difference between configuration conditions of target device and estimation target device, 1202...adjustment candidate list unit

Claims

1. A charged particle beam equipment management system having at least one charged particle beam equipment and an equipment management device, wherein the equipment management device comprises: an electron optics simulation unit that calculates the states of an evaluation target equipment, which is a charged particle beam equipment, and a target equipment; an equipment state correction candidate calculation unit that calculates correction conditions for equipment components so that the evaluation target equipment approaches the state of the target equipment; and an equipment state estimation unit that calculates the difference between the evaluation target equipment and the target equipment when corrected in accordance with the correction conditions, wherein the equipment state correction candidate calculation unit calculates the cost of performing correction on the equipment, and outputs the difference between the calculated correction conditions and the target equipment after correction, as well as the correction cost.

2. A charged particle beam equipment management system as described in claim 1, characterized in that the equipment state is the electromagnetic field distribution in the electron optical system, the state of the electron beam that fluctuates due to said electromagnetic field distribution, and the detection conditions for scattered electrons generated by irradiation of the electron beam.

3. A charged particle beam equipment management system as described in claim 2, characterized in that, when determining the equipment state, the electron optical system simulation unit changes the conditions of the equipment components and determines the equipment state through logical calculations including simulations, the equipment state estimation unit compares the determined equipment state with images obtained by capturing images using the equipment to be evaluated under a plurality of imaging conditions, and sets the conditions of the equipment components that show similar trends under a plurality of imaging conditions as the equipment components of the equipment to be evaluated, and sets the equipment state determined through logical calculations under the conditions of the equipment components of the equipment to be evaluated as the equipment state of the equipment to be evaluated.

4. A charged particle beam equipment management system as described in claim 3, characterized in that the equipment state estimation unit learns the relationship between the equipment state and the captured image in order to compare the equipment state and the captured image under a plurality of imaging conditions, calculates the equipment state from the captured image using the learning results, and compares the equipment state calculated from the captured image with the equipment state used for learning.

5. A charged particle beam equipment management system according to claim 1, characterized in that the correction conditions for the equipment components that bring the equipment to be evaluated closer to the state of the target equipment include conditions that match the conditions for the equipment components.

6. A charged particle beam equipment management system according to claim 1, characterized in that the correction conditions for the equipment components that bring the equipment to be evaluated closer to the state of the target equipment include conditions under which the conditions for the equipment components do not match.

7. A charged particle beam equipment management system as claimed in claim 1, characterized in that when calculating the cost of performing correction on the equipment, the equipment status correction candidate calculation unit stores the cost for each correction item in advance and reads out the cost for the relevant correction item.

8. A charged particle beam equipment management system as claimed in claim 1, characterized in that the cost of performing corrections on the equipment includes one or more of the following: parts costs and labor costs for part replacement, equipment adjustment costs after replacement, equipment downtime and production loss costs for the measurement object due to equipment downtime.

9. A method for managing a charged particle beam device in a charged particle beam device management system having at least one charged particle beam device and an device management device, wherein an electron optical system simulation unit constituting the device management device determines the states of an evaluation target device and a target device, which are charged particle beam devices; an device state correction candidate calculation unit constituting the device management device determines correction conditions for device components such that the evaluation target device approaches the state of the target device; an device state estimation unit constituting the device management device determines the difference between the evaluation target device and the target device when the evaluation target device is corrected in accordance with the correction conditions; and the device state correction candidate calculation unit determines the cost of performing the correction on the device, and outputs the difference between the determined correction conditions and the target device after correction, as well as the correction cost.

10. A method for managing a charged particle beam device according to claim 9, characterized in that the state of the device is the electromagnetic field distribution in the electron optical system, the state of the electron beam which fluctuates due to said electromagnetic field distribution, and the detection conditions for scattered electrons generated by irradiation with the electron beam.

11. A method for managing a charged particle beam device as described in claim 10, wherein, when determining the state of the device, the electron optical system simulation unit changes the conditions of the device components and determines the device state through logical calculations including simulations; the device state estimation unit compares the determined device state with images obtained by capturing images of the device to be evaluated under a plurality of imaging conditions, and sets the conditions of the device components that show similar trends under a plurality of imaging conditions as the device components of the device to be evaluated; and sets the device state determined through logical calculations under the conditions of the device components of the device to be evaluated as the device state of the device to be evaluated.

12. A method for managing a charged particle beam device as described in claim 11, characterized in that the device state estimation unit learns the relationship between the device state and the captured image in order to compare the device state and the captured image under a plurality of imaging conditions, calculates the device state from the captured image using the learning results, and compares the device state calculated from the captured image with the device state used for learning.

Images