Imaging System and Imaging Method

Abstract

The present invention improves throughput before observation of a lamella is completed, and also automatically makes corrections even when the lamella is greatly inclined. An imaging system 10 of the present disclosure comprises: a surface shape measurement device 3 which measures three-dimensional coordinate information about the surface shape of a lamella having a layered structure; a computer system 1 which, on the basis of the three-dimensional coordinate information measured by the surface shape measurement device 3, calculates correction information for correcting the angle and height of the lamella during imaging of the lamella, and which transmits the calculated correction information; and a charged particle beam device 4 which receives the correction information, corrects the angle and height of the lamella on the basis of the correction information, and irradiates the lamella of which the angle and height have been corrected with a charged particle beam to image the lamella.

Description

Technical Field

[0001] The present disclosure relates to an imaging system and an imaging method, and more particularly to an imaging system and an imaging method for imaging a lamella having a laminated structure.

Background Art

[0002] With the progress of miniaturization of semiconductor devices, the influence of LER (Line Edge Roughness) on device performance has been increasing. Along with this, the need for observation using a TEM (Transmission Electron Microscope) capable of defect analysis and length measurement at the sub-nanometer scale is considered to be increasing. Due to the increasing need for observation using a TEM, automation of a series of processes from sample processing by a FIB (Focused Ion Beam) processing apparatus to observation using a TEM and improvement in throughput are required.

[0003] Among a series of processes up to observation using a TEM, there is a procedure for adjusting the angle and height of a stage on which a lamella is mounted to conditions that provide higher resolution for each of a plurality of lamellas arranged on a TEM mesh. Methods for automating the above process have been studied in the past. Here, the lamella refers to a thin film sample for observation using a TEM.

[0004] For example, Patent Document 1 discloses a method of automatically and highly accurately adjusting the tilt angle of a stage to the crystal orientation of a desired sample using an image of a diffraction pattern including Kikuchi lines.

[0005] Also, Patent Document 2 discloses a method of obtaining the height distribution of a sample by performing multi-resolution analysis using wavelet transform or discrete wavelet transform.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] Adjustment of the angle of the stage by the method described in Patent Document 1 and Z-axis adjustment of the stage by the method described in Patent Document 2 can achieve sufficient accuracy for accurate defect analysis and length measurement. However, since the adjustment takes a long time, there is a problem that the throughput until the observation using the TEM is completed decreases. In addition, particularly in the adjustment of the angle of the stage, the range of angles that can be automatically adjusted is narrow, and there is a problem that automatic correction cannot be performed when the stage is greatly tilted with a lamella placed on the TEM mesh.

[0008] Therefore, an object of the present disclosure is to provide an imaging system and an imaging method that improve the throughput until the observation of the lamella is completed and can automatically correct even when the lamella is greatly tilted. [Means for Solving the Problems]

[0009] In order to solve the above problems, the imaging system of the present disclosure includes a surface shape measuring device that measures three-dimensional coordinate information of the surface shape of a lamella having a laminated structure, and a computer system that calculates correction information for correcting the angle and height of the lamella at the time of imaging the lamella based on the three-dimensional coordinate information measured by the surface shape measuring device and transmits the calculated correction information, and a charged particle beam device that receives the correction information, corrects the angle and height of the lamella based on the correction information, and irradiates the lamella with the corrected angle and height with a charged particle beam to image the lamella. [Effects of the Invention]

[0010] According to the present disclosure, the throughput until the observation of the lamella is completed is improved, and automatic correction can be performed even when the lamella is greatly tilted.

[0011] Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

Brief Description of the Drawings

[0012]

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Modes for Carrying Out the Invention

[0013] Embodiments of the present disclosure will be described in detail based on the drawings. In the following embodiments, it goes without saying that the configuration (including the steps of the flowchart) is not necessarily essential except in cases where it is particularly specified and in cases where it is considered clearly essential in principle. Hereinafter, preferred embodiments of the present disclosure will be described with reference to the drawings.

[0014] 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, and range, etc. in order to facilitate the understanding of the present disclosure.

[0015] In the description, when explaining the processing by a program, the program, function, processing unit, etc. may be mainly described. However, the main body of these as hardware is a processor, or a controller, device, calculator, system, etc. composed of the processor and the like. The calculator executes processing according to a program read onto a memory while appropriately using resources such as a memory and a communication interface by the processor. Thereby, a predetermined function, processing unit, etc. are realized. The processor is composed of, for example, a semiconductor device such as a CPU or a GPU. The processor is composed of a device or circuit capable of performing a predetermined operation. The processing is not limited to software program processing and can also be implemented by a dedicated circuit. FPGA, ASIC, CPLD, etc. are applicable to the dedicated circuit.

[0016] The program may be installed in advance as data in the target calculator, or may be distributed and installed as data from the program source to the target calculator. The program source may be a program distribution server on a communication network or a non-transitory computer-readable storage medium (for example, a memory card or a magnetic disk). The program may be composed of a plurality of modules. The computer system may be composed of a plurality of devices. The computer system may be composed of a cloud computing system or the like.

[0017] Various data and information are composed of, for example, structures such as tables and lists, but are not limited thereto. Also, the expressions of identification information, identifiers, IDs, names, numbers, etc. are mutually replaceable.

[0018] For the purpose of description, the X direction, Y direction, Z direction, etc. may be used. These directions (or axes) intersect each other, particularly orthogonally. In particular, the Z direction corresponds to the direction of up and down, height, depth, thickness, etc. Also, unless otherwise specified, the coordinate system of the three-dimensional space is described on the premise of a left-handed system. Also, when explaining the rotation direction in space, α, β, γ, etc. may be used. These directions respectively represent Euler angles [rad] rotating around the X axis, Y axis, and Z axis.

[0019] [First Embodiment] <Imaging System> The imaging system 10 of the first embodiment measures the angles and heights of a plurality of lamellas arranged on a TEM mesh, calculates correction information for correcting the angles and heights of the TEM stage 5, and automatically adjusts the TEM stage 5 of the charged particle beam apparatus 4 based on the correction information. The TEM mesh is a net-like member on which a plurality of lamellas can be arranged.

[0020] FIG. 1 is a diagram showing the overall configuration of the imaging system according to the first embodiment. The imaging system 10 in FIG. 1 includes a computer system 1, a lift-out device 2, and a charged particle beam apparatus 4. The computer system 1, the lift-out device 2, and the charged particle beam apparatus 4 are connected to be communicable with each other via a communication network such as a LAN 9. Even when the computer system 1, the lift-out device 2, and the charged particle beam apparatus 4 are not connected by the above-described communication network, for example, a user can store data and information in a storage medium such as a memory card and carry it, thereby realizing input / output of data and information among the computer system 1, the lift-out device 2, and the charged particle beam apparatus 4.

[0021] The computer system 1 includes a processor 201, a memory 202, a storage device 203, a communication interface 204, etc., and they are connected to each other by a bus. The storage device 203 stores various programs and data. The program includes device cooperation software 210 described later. The communication interface 204 is connected to be communicable with the LAN 9.

[0022] The computer system 1 does not necessarily exist as independent hardware, and may be, for example, a common PC with the control PC of the lift-out device 2 or the charged particle beam device 4.

[0023] The lift-out device 2 is a device that picks up a lamella and places it on a TEM mesh fixed on the sample holder 100. A lamella is a thin sample processed from a sample 101 by a device such as an FIB processing device so that an observation location can be observed by the charged particle beam device 4, and has a laminated structure.

[0024] Note that a device for creating a lamella such as an FIB processing device may be incorporated in the lift-out device 2. In that case, the sample 101 is introduced into the lift-out device 2 in a state where the observation location has not been processed into a lamella.

[0025] Inside the lift-out device 2, a surface shape measurement device 3 is incorporated. The surface shape measurement device 3 satisfies the following two requirements. The first is that it can acquire three-dimensional coordinate information (X, Y, Z), and the second is that sufficient spatial resolution (at least three or more three-dimensional coordinate information) can be obtained to determine the angle and height of the measurement target. Specifically, a white light interference microscope (CSI), a laser confocal microscope (LSM), an optical microscope or an electron microscope (X, Y) combined with a height sensor (Z), an optical microscope or an electron microscope that performs imaging using a plurality of directions or a plurality of detectors to acquire three-dimensional coordinates, etc. can be mentioned.

[0026] Among the surface shape measurement devices 3, the white light interference microscope has a high measurement speed and can obtain sufficient spatial resolution (especially in the Z-axis direction) for measuring the surface shape of the lamella. Therefore, in this embodiment, it can be said that it is a suitable device.

[0027] The charged particle beam apparatus 4 is an apparatus for observing a plurality of lamellas arranged on a TEM mesh by a lift-out apparatus 2. The charged particle beam apparatus 4 receives a sample holder 102 to which a TEM mesh on which a plurality of lamellas are arranged is fixed, irradiates a plurality of lamellas arranged on the TEM mesh with a charged particle beam, and images the plurality of lamellas. The charged particle beam apparatus 4 is a transmission charged particle beam apparatus, and is, for example, a TEM (Transmission Electron Microscope) or a STEM (Scanning Transmission Electron Microscope). Here, the TEM and / or STEM will be described as a TEM.

[0028] <Method for imaging lamellas by the imaging system 10> FIG. 2 is a flowchart showing the processes (including operations by the user) executed by the imaging system in the first embodiment. With reference to FIG. 2, a method for imaging lamellas by the imaging system 10 will be described.

[0029] In step S1, the user or an automatic transfer device or the like inputs a sample holder 100 and a sample 101 to which a TEM mesh is fixed into the lift-out apparatus 2. The sample 101 corresponds to, for example, a semiconductor wafer on which lamellas have been created by an FIB processing apparatus.

[0030] In step S2, the surface shape measuring device 3 measures the entire surface shape of the TEM mesh fixed to the sample holder 100. In step S2, although the entire surface shape of the TEM mesh is measured, the TEM mesh may be divided into a plurality of sections, and the surface shape may be measured for each of the plurality of sections, or the surface shape may be measured for each location where the lamellas are arranged.

[0031] In step S3, the lift-out apparatus 2 picks up a lamella from the sample 101 and arranges it on the TEM mesh. The lamella is picked up using a manipulator or tweezers.

[0032] In step S4, the surface shape measuring device 3 measures the surface shape of each lamella arranged on the TEM mesh. As the reference angle and height when measuring the surface shape of the lamella, the frame of the TEM mesh may be used, or the value calibrated first may be used. The magnification when measuring the surface shape of each lamella arranged on the TEM mesh in step S4 may be higher than the magnification when measuring the overall surface shape of the TEM mesh in step S2.

[0033] In step S5, the computer system 1 calculates correction information for adjusting the angle and height of the TEM stage 5 of the charged particle beam device 4 based on the surface shape of the TEM mesh measured in step S2 and the surface shape of the lamella measured in step S4. The specific calculation method will be described in <Calculation Method of Correction Information for TEM Stage 5> described later. Then, the computer system 1 transmits the calculated correction information to the charged particle beam device 4.

[0034] In step S6, the computer system 1 determines whether the calculation of the correction information for all the lamellas arranged on the TEM mesh is completed. When the computer system 1 determines that the calculation of the correction information for all the lamellas arranged on the TEM mesh is not completed (step S6: No), it returns to the process of step S3. When it determines that the calculation of the correction information for all the lamellas arranged on the TEM mesh is completed (step S6: Yes), it performs the process of step S7.

[0035] In step S7, the user or an automatic transfer device, etc., takes out the sample holder 102 with the TEM mesh fixed from the lift-out device 2 and inserts it into the charged particle beam device 4.

[0036] In step S8, the charged particle beam apparatus 4 receives the correction information of the TEM stage 5 calculated in step S5, and adjusts (corrects) the angles (α·β) and height (Z) of the TEM stage 5 based on the received correction information. The angles (α·β) of the TEM stage 5 mean the angle α of the TEM stage 5 with respect to the X-axis direction and the angle β of the TEM stage 5 with respect to the Y-axis direction in a three-dimensional orthogonal coordinate system having the X-axis, Y-axis, and Z-axis. Also, the height (Z) means the position of the TEM stage 5 in the Z-axis direction.

[0037] In step S9, in order for the charged particle beam apparatus 4 to perform correction with higher accuracy than the adjustment of the angles (α·β) and height (Z) of the TEM stage 5 in step S8, fine adjustment of the angles (α·β) and height (Z) of the TEM stage 5 is performed using the phenomenon caused by the charged particle beam. For the adjustment of the angles, for example, alignment using the electron beam diffraction phenomenon may be used. For example, for the adjustment of the angles, an image of a diffraction pattern including Kikuchi lines may be used to automatically and highly accurately adjust the angles (α·β) of the TEM stage 5 to the crystal orientation of the lamella. For the adjustment of the height, the height (Z) of the TEM stage 5 may be adjusted using the result of obtaining the height distribution of the sample by performing multi-resolution analysis by wavelet transform or discrete wavelet transform.

[0038] After performing the rough adjustment of the angles (α·β) and height (Z) of the TEM stage 5 in step S8, by performing the fine adjustment of the angles (α·β) and height (Z) of the TEM stage 5 in step S9, the adjustable range of the angles (α·β) and height (Z) of the TEM stage 5 increases, and a reduction in the time required for the adjustment in step S9 is expected.

[0039] In step S10, in the TEM stage 5 whose angles (α·β) and height (Z) have been adjusted by steps S8 and S9, the charged particle beam apparatus 4 irradiates each lamella with the charged particle beam and performs imaging of each lamella.

[0040] In the imaging system 10, by performing these steps S1 to S10, it is possible to observe the lamella in a state where the angles (α·β) and the height (Z) are adjusted automatically and in a short time. The adjustment of the angle and height of the lamella is a necessary condition for accurate length measurement. Therefore, it can be said that the present disclosure contributes to the improvement of the throughput of a series of processes in TEM imaging for the purpose of length measurement and defect observation of semiconductor samples.

[0041] <Function of software for inter-device cooperation> FIG. 3 is a functional block diagram of software for inter-device cooperation in the first embodiment. With reference to FIG. 3, the function of the software for inter-device cooperation 210 will be described. The software for inter-device cooperation 210 includes a surface shape acquisition unit 300 that acquires measurement data of the surface shapes of the TEM mesh and the lamella from the surface shape measurement device 3, a correction information calculation unit 301 that calculates correction information for adjusting the angles and height of the TEM stage 5 from the surface shape acquisition unit 300, and a correction information transmission unit 302 that transmits the correction information calculated by the correction information calculation unit 301 to the charged particle beam device 4.

[0042] <Data stored in the storage device> FIG. 4 is a configuration diagram of data stored in the storage device of the computer system in the first embodiment. As shown in FIG. 4, the storage device 203 stores surface shape measurement data 400 and TEM stage correction information 410. The surface shape measurement data 400 includes surface shape data 401 indicating the overall surface shape of the TEM mesh measured in step S2 of FIG. 2, and surface shape data 402 indicating the surface shape of each lamella measured in step S4. The computer system 1 calculates TEM stage correction information 411 for each lamella based on the surface shape measurement data 400. For example, the computer system 1 calculates correction information 411a for adjusting the angle and height of the TEM stage 5 during imaging of the lamella (1) based on the surface shape data 401 indicating the overall surface shape of the TEM mesh and the surface shape data 402a indicating the surface shape of the lamella (1), and stores it in the storage device 203. Further, for example, the computer system 1 calculates correction information 411b for adjusting the angle and height of the TEM stage 5 during imaging of the lamella (2) based on the surface shape data 401 indicating the overall surface shape of the TEM mesh and the surface shape data 402b indicating the surface shape of the lamella (2) different from the lamella (1), and stores it in the storage device 203. The TEM stage correction information 410 stores the correction information 411 for each lamella.

[0043] <Calculation method of correction information for TEM stage 5> FIG. 5 is a flowchart showing a calculation method for calculating TEM stage correction information from the surface shape measurement data in the first embodiment. The calculation method in FIG. 5 assumes a case where the warpage of the TEM mesh and the lamella is small and can be approximated by a plane. Note that the equation of the plane may be based on either the substrate (metal) portion or the film portion of the TEM mesh.

[0044] In step S51, the computer system 1 obtains parameters a1, b1, c1, d1 of the equation of the plane approximating the surface of the TEM mesh shown in the following mathematical formula (1) from the surface shape measurement data of the TEM mesh.

[0045] a1x + b1y + c1z = d1…(1)

[0046] There are various methods for obtaining the equation of a plane from surface shape measurement data. For example, methods such as detecting the positions of meshes using image processing such as template matching from surface shape measurement data and obtaining the equation of a plane from three pre-specified points on a TEM mesh can be considered.

[0047] The three points specified above can automatically select good conditions by using the RANSAC (Random Sample Consensus) method. Specifically, after obtaining the equation of a temporary plane with any three points on the mesh, count the number (consensus) of all surface shape measurement data points on the TEM mesh where the distance from the temporary plane is within the threshold. By repeating the above multiple times and adopting the equation of the plane with the most obtained consensus, an equation of the plane of the mesh with higher approximation accuracy can be obtained.

[0048] When obtaining the equation of a plane, it is sufficient to have the spatial coordinates of at least three points on the TEM mesh or lamella. However, when obtaining an equation of a plane with higher approximation accuracy using methods such as the RANSAC method, sufficient surface shape data is required. Therefore, it can be said that surface shape measurement methods such as CSI, which can obtain multiple spatial coordinates on the TEM mesh or lamella with sufficient spatial resolution, are also suitable in this method.

[0049] In step S52, the computer system 1 obtains the angles (α1·β1) of the TEM mesh. The angles (α1·β1) of the TEM mesh are obtained from the equation of the plane of the TEM mesh (mathematical formula (1)) measured in step S51 using the following mathematical formulas (2-1) and (2-2).

[0050] α1 = atan(-b1 / c1)…(2-1) β1 = atan(-a1 / c1)…(2-2)

[0051] In step S53, the computer system 1 obtains the height (Z1) of the TEM mesh at the position (X1, Y1) on the X-Y plane of each lamella. The height (Z1) of the TEM mesh is obtained from the equation of the plane of the TEM mesh measured in step S51 (mathematical formula (1)) using the following mathematical formula (3).

[0052] Z1=(d1 - a1X1 - b1Y1) / c1…(3)

[0053] Note that the angle (α1) of the TEM mesh with respect to the X-axis direction, the angle (β1) of the TEM mesh with respect to the Y-axis direction, and the height (Z1) of the TEM mesh in the Z-axis direction obtained in steps S52 and S53 are used as the reference angles and height when measuring the surface shape of the lamella in the subsequent steps.

[0054] In step S54, the computer system 1 obtains the equation of the plane from the surface shape measurement data of the lamella. The method of obtaining the equation of the plane is the same as that of the TEM mesh in step S51. Either the processed part or the unprocessed part can be used as the reference part of the plane.

[0055] In step S55, the computer system 1 obtains the angles (α2·β2) and height (Z2) of each lamella from the equation of the plane of the lamella. The method of obtaining the angles (α2·β2) of each lamella is the same as that of the TEM mesh in step S52. Also, for the height (Z2) of each lamella, methods such as performing image detection on the thinned part that is the object of observation by the charged particle beam device 4 and obtaining the average value or median value of the height data of the corresponding part can be considered.

[0056] In step S56, the computer system 1 obtains correction information (α, β, Z) for adjusting (correcting) the angle and height of the TEM stage 5 based on the angle (α1, β1) and height (Z1) of the TEM mesh obtained in steps S52 and S53, and the angle (α2, β2) and height (Z2) of each lamella obtained in step S55. This correction information is obtained using the following mathematical formulas (4-1) to (4-3) when measuring the surface shape of the lamella based on the TEM mesh.

[0057] α = α1 + α2 + α offset …(4-1) β = β1 + β2 + β offset …(4-2) Z = Z1 + Z2 + Z offset …(4-3)

[0058] The α in the above mathematical formulas (4-1) to (4-3) offset , β offset , and Z offset are values caused by reasons such as the angle of the TEM stage 5, the deviation of the conveying device that conveys the lamella, and the deviation of the fixed position of the TEM stage 5. It can be considered to obtain them in advance for each device, or to determine a reference location on the TEM stage 5 and calibrate it each time.

[0059] [Second Embodiment] The method shown in the first embodiment is applicable when the TEM mesh and the lamella have little warping. When the warping of the lamella is large, the error becomes large with the above method. Therefore, in the second embodiment, a method for adjusting the angle and height of the TEM stage 5 even when the warping of the lamella is large is shown. FIG. 6 is a flowchart showing a method for calculating correction information of the TEM stage from the surface shape measurement data in the second embodiment.

[0060] <Method for Calculating Position Correction Information> In the second embodiment, it is premised that among the surface shape measurement devices 3, a surface shape measurement device capable of acquiring a height image such as CSI is used. A height image is data in which the height (Z) of the lamella at the corresponding location (X, Y) is held in the pixel value portion of normal image data. The height image may be subjected to noise removal using a Gaussian filter or a median filter as preprocessing.

[0061] In step S61, the computer system 1 obtains the height (Z1) of the TEM mesh around each lamella position of the TEM mesh from the surface shape measurement data of the TEM mesh. The position of the lamella can be obtained using image detection or the like. The height (Z1) of this TEM mesh may be obtained from the average value or the median value of the Z coordinates of several pixels around the lamella position.

[0062] In step S62, the computer system 1 obtains the angles (α1·β1) of the TEM mesh at each lamella position by acquiring the first-order differential image of the height image of the TEM mesh. The first-order differential of the height image of the TEM mesh is performed in both the X-axis direction and the Y-axis direction. As a specific calculation method, a method using numerical differentiation such as forward difference approximation or central difference approximation using adjacent height values can be considered. At this time, the denominator term is the length per 1 pixel (2 pixels in the case of central difference approximation) in the X and Y axis directions. The angles obtained here can be used to calculate the angle α1 in the X-axis direction and the angle β1 in the Y direction by calculating the atan value in the same manner as in formulas (2-1) and (2-2). Note that it may be obtained by using the average value or the median value of several pixels around each lamella position (X1, Y1).

[0063] In step S63, the computer system 1 obtains the height (Z2) of each lamella from the surface shape measurement data of each lamella. As for the height (Z2) of each lamella, a method of obtaining the observation location of the lamella by image detection and calculating the average value or the median value of the height of the corresponding area can be considered.

[0064] In step S64, the computer system 1 obtains a first derivative image obtained by differentiating the height image of the lamella in the (X, Y) directions, and determines the angles (α2·β2) of the respective lamellas. The specific calculation procedure is the same as that in step S62.

[0065] In step S65, the computer system 1 calculates correction information (α·β·Z) for adjusting (correcting) the angle and height of the TEM stage 5 based on the angles (α1·β1) of the TEM mesh and the angles (α2·β2) of the respective lamellas and the height (Z1) of the TEM mesh and the heights (Z2) of the respective lamellas. The calculation method is the same as that in step S56 of FIG. 5.

[0066] [Effects of the First and Second Embodiments] Next, the effects exhibited by the imaging system 10 of the first and second embodiments will be described with reference to FIGS. 7 and 8.

[0067] [Automatically Adjustable Range of Angle (α·β)] FIG. 7 is a diagram showing the automatically adjustable range of the angle (α·β) of the TEM stage. The origin 710 in FIG. 7 represents the angle of the TEM stage 5 when imaging is performed, that is, the point at which the adjustment of the angle of the TEM stage 5 is completed.

[0068] The automatically adjustable range 701 of the angle (α·β) of the TEM stage 5 using the electron beam diffraction phenomenon of the prior art is small compared to the physically movable range of the TEM stage 5, and it has been difficult to automatically correct a largely inclined lamella. Also, it has not been possible to determine whether the lamella is at an angle within the automatically adjustable range 701 before executing the automatic adjustment.

[0069] In the first and second embodiments, for example, when the starting position 711 of the angle of the lamella is within the automatically adjustable range (the movable range of the TEM stage) 702 of the present disclosure, that is, when the lamella has an angle greater than the automatically adjustable range 701 in the prior art, by using the angle (α2·β2) of the lamella obtained from the surface shape measurement data, the TEM stage 5 can be tilted to a position 712 within the automatically adjustable range of the angle (α·β) of the TEM stage 5 that utilizes the electron diffraction phenomenon in the prior art.

[0070] Furthermore, when the starting position 713 is in the non-adjustable range 703, a lamella tilted beyond the movable range of the TEM stage 5 or the angle measurable range of the surface shape measuring device can be excluded from the observation target in advance. This can be said to be advantageous in improving throughput compared with the prior art in which it is impossible to determine whether a lamella is significantly deviated from the automatically adjustable range until automatic adjustment is executed.

[0071] <Search operation for the automatic adjustment speed of the angle (α·β) of the TEM stage> FIG. 8 is a diagram showing the operation of automatically adjusting the angle (α·β) of the TEM stage. Here, even within the automatically adjustable range 701 of the prior art in FIG. 8, the point contributing to improving the observation throughput will be described.

[0072] In the case of automatic adjustment using the electron diffraction phenomenon of the prior art, the measurement error of the angle deviation increases due to reasons such as a decrease in the number of diffraction spots as the deviation from the target angle becomes larger. Therefore, as in the search path 820 from the starting point 814, the calculation of the angle deviation is performed multiple times, and a search operation is taken to approach the target position 710.

[0073] On the other hand, in the first and second embodiments, by obtaining the angle of the lamella in advance from the surface shape of the lamella, as shown in the search path 821, it is possible to align with the position 815 within the error range 804 of the angle measured from the surface shape at the first time from the starting point. This makes it possible to shorten the time of the search operation compared with the prior art.

[0074] <Search operation for the automatic adjustment speed of height (Z)> FIG. 9 is a diagram showing a search operation for adjusting the height of the lamella. The Z-axis direction of the charged particle beam apparatus 4 is generally realized by obtaining the value of the height (Z) at which the evaluation value obtained by means such as multi-resolution analysis by wavelet transform or discrete wavelet transform from an image becomes maximum (or minimum).

[0075] As shown in the graph, the evaluation value 900 calculated by the above method tends to change less when it is far from the target position 920. Therefore, in the prior art, for example, when the start position 921 is within the search range 910 in the prior art, it is impossible to determine whether the target position 920 is in the + or - direction of the Z-axis. Therefore, it is necessary to scan in both the + and - directions within an appropriate range from the start position 922 to the end position 923 to search for the value of Z at which the evaluation value becomes maximum.

[0076] In the first and second embodiments, by obtaining height correction information from the surface shape, it is possible to move 930 from the start position 921 to a position closer to the target height 924. Since it is only necessary to search within the range of the height measurement error of the surface shape measuring device from the position 924, the search range can be reduced, and an improvement in throughput is expected.

[0077] Among the surface shape measuring devices 3, in particular, CSI has excellent spatial resolution in the Z-axis direction, so the effect of reducing the search range is particularly large in the adjustment of the position (height) in the Z-axis direction.

[0078] Furthermore, when a sufficient change (gradient) in the evaluation value can be obtained in the vicinity of the start point 924 in the present disclosure, the search direction can be narrowed down to one direction. That is, it can be said that the adjustment can be performed within a search range 912 smaller than the search range 911.

[0079] Note that the present disclosure is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present disclosure, and are not necessarily limited to those having all the configurations described. Also, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0080] For example, in the first and second embodiments, the angle and height of the lamella are corrected based on the three-dimensional coordinate information measured by the surface shape measuring device 3, but at least one of the angle or height of the lamella may be corrected. In this case, for example, for the angle or height of the lamella that is not corrected, the phenomenon by the charged particle beam may be utilized for correction as in step S9 of FIG. 2.

Description of Reference Numerals

[0081] 1... computer system, 2... lift-out device, 3... surface shape measuring device, 4... charged particle beam device, 5... TEM stage, 10... imaging system

Claims

1. A surface shape measuring device that measures three-dimensional coordinate information of the surface shape of a lamella having a laminated structure, A computer system that calculates correction information for correcting the angle and height of the lamella at the time of imaging the lamella based on the three-dimensional coordinate information measured by the surface shape measuring device, and transmits the calculated correction information, A charged particle beam device that receives the correction information, corrects the angle and height of the lamella based on the correction information, and irradiates the lamella with the corrected angle and height with a charged particle beam to image the lamella, and is provided with, The surface shape measuring device measures three-dimensional coordinate information of the surface shape of a mesh on which a plurality of the lamellas can be arranged, and three-dimensional coordinate information of the surface shape of each of the lamellas arranged on the mesh, The computer system calculates the correction information based on the three-dimensional coordinate information of the surface shape of the mesh and the three-dimensional coordinate information of the surface shape of the lamella, An imaging system characterized by this.

2. A surface shape measuring device that measures three-dimensional coordinate information of the surface shape of a lamella having a laminated structure, A computer system that calculates correction information for correcting the angle and height of the lamella at the time of imaging the lamella based on the three-dimensional coordinate information measured by the surface shape measuring device, and transmits the calculated correction information, A charged particle beam device that receives the correction information, corrects the angle and height of the lamella based on the correction information, and irradiates the lamella with the corrected angle and height with a charged particle beam to image the lamella, and is provided with, The charged particle beam device corrects the angle and height of the lamella based on the correction information, and further corrects the angle of the lamella using the diffraction phenomenon by the charged particle beam to image the lamella, An imaging system characterized by this.

3. Based on the three-dimensional coordinate information of the surface shape of the first lamella measured by the surface shape measuring device and the three-dimensional coordinate information of the surface shape of the mesh, the computer system calculates first correction information for correcting the angle and height of the first lamella during imaging of the first lamella, and based on the three-dimensional coordinate information of the surface shape of a second lamella different from the first lamella measured by the surface shape measuring device and the three-dimensional coordinate information of the surface shape of the mesh, calculates second correction information for correcting the angle and height of the second lamella during imaging of the second lamella The imaging system according to claim 1, characterized in that.

4. Based on the three-dimensional coordinate information of the surface shape of the first lamella measured by the surface shape measuring device and the three-dimensional coordinate information of the surface shape of the mesh at the position where the first lamella is arranged, the computer system calculates first correction information for correcting the angle and height of the first lamella during imaging of the first lamella, and based on the three-dimensional coordinate information of the surface shape of a second lamella different from the first lamella measured by the surface shape measuring device and the three-dimensional coordinate information of the surface shape of the mesh at the position where the second lamella is arranged, calculates second correction information for correcting the angle and height of the second lamella during imaging of the second lamella The imaging system according to claim 1, characterized in that.

5. The surface shape measuring device acquires the three-dimensional coordinate information of at least three or more points on the lamella, and calculates the correction information based on the three-dimensional coordinate information of the at least three or more points The imaging system according to claim 1 or 2, characterized in that.

6. The surface shape measuring device is a white light interference microscope The imaging system according to claim 1 or 2, characterized in that.

7. Measuring the three-dimensional coordinate information of the surface shape of a lamella having a laminated structure by a surface shape measuring device Calculating, by a computer, correction information for correcting the angle and height of the lamella during imaging of the lamella based on the three-dimensional coordinate information measured by the surface shape measuring device, and transmitting the calculated correction information to a charged particle beam device receiving the correction information by the charged particle beam device, correcting the angle and height of the lamella based on the correction information, and irradiating the lamella with the corrected angle and height with a charged particle beam to image the lamella; further comprising measuring, by the surface shape measuring device, three-dimensional coordinate information of the surface shape of a mesh on which a plurality of the lamellas can be arranged; calculating the correction information includes calculating the correction information based on the three-dimensional coordinate information of the surface shape of the mesh and the three-dimensional coordinate information of the surface shape of the lamella arranged on the mesh; An imaging method characterized by the above.

8. measuring, by a surface shape measuring device, three-dimensional coordinate information of the surface shape of a lamella having a laminated structure; calculating, by a computer, correction information for correcting the angle and height of the lamella at the time of imaging the lamella based on the three-dimensional coordinate information measured by the surface shape measuring device, and transmitting the calculated correction information to a charged particle beam device; receiving the correction information by the charged particle beam device, correcting the angle and height of the lamella based on the correction information, and irradiating the lamella with the corrected angle and height with a charged particle beam to image the lamella; further comprising, after correcting the angle and height of the lamella based on the correction information, further correcting the angle of the lamella by using the diffraction phenomenon caused by the charged particle beam by the charged particle beam device; An imaging method characterized by the above.

9. calculating the correction information includes calculating first correction information for correcting the angle and height of the first lamella at the time of imaging the first lamella based on the three-dimensional coordinate information of the surface shape of the first lamella measured by the surface shape measuring device and the three-dimensional coordinate information of the surface shape of the mesh, and calculating second correction information for correcting the angle and height of the second lamella at the time of imaging the second lamella based on the three-dimensional coordinate information of the surface shape of the second lamella different from the first lamella measured by the surface shape measuring device and the three-dimensional coordinate information of the surface shape of the mesh; The imaging method according to claim 7, characterized by the above.

10. Calculating the correction information includes calculating first correction information for correcting the angle and height of the first lamella at the time of imaging the first lamella based on the three-dimensional coordinate information of the surface shape of the first lamella measured by the surface shape measuring device and the three-dimensional coordinate information of the surface shape of the mesh at the position where the first lamella is disposed, and calculating second correction information for correcting the angle and height of the second lamella at the time of imaging the second lamella based on the three-dimensional coordinate information of the surface shape of the second lamella different from the first lamella measured by the surface shape measuring device and the three-dimensional coordinate information of the surface shape of the mesh at the position where the second lamella is disposed. The imaging method according to claim 7, characterized in that. Claim 11 Calculating the correction information includes calculating the correction information based on the three-dimensional coordinate information of at least three or more points on the lamella. The imaging method according to claim 7 or 8, characterized in that. Claim 12 The surface shape measuring device is a white interference microscope. The imaging method according to claim 7 or 8, characterized in that.

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