Sample observation system

Abstract

To provide a sample piece relocation device which can prevent breakage of a sample piece and can accurately execute a predetermined relocation operation accurately.SOLUTION: A sample piece relocation device (10) includes an optical interference measurement device (11), a sample piece carrying device (13), and a controller (21). The controller (21) controls the sample piece carrying device (13) on the basis of information on processing of manufacturing a sample piece by radiating a charge particle beam to a sample (S) by a charge particle beam device. The sample piece carrying device (13), which is controlled by the controller (21), separates and takes the sample piece from the sample (S), and carries the sample piece to the sample piece holder by holding the sample piece.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a sample piece transfer device. This application claims priority based on Japanese Patent Application No. 2021-012693, filed on January 29, 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] Conventionally, there has been known an apparatus that prepares a specimen for observation under a transmission electron microscope by irradiating a wafer-shaped specimen with a charged particle beam of electrons or ions, extracts the specimen from the specimen using a probe attached to a manipulator, and places the specimen on a mesh (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-141620 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional apparatus, when transferring a minute sample piece from a sample onto a mesh, it is desired to perform a predetermined transfer operation with high accuracy while preventing damage to the sample piece.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a sample piece transfer device capable of performing a predetermined transfer operation with high accuracy while preventing damage to the sample piece. [Means for solving the problem]

[0006] In order to solve the above problems, the sample piece transfer device of the present invention comprises a sample piece transport mechanism that transports the sample piece from a sample on which the sample piece is formed to a sample piece holder, and a control device that controls the sample piece transport mechanism based on information regarding processing for producing the sample piece by irradiating the sample with a charged particle beam using a charged particle beam device, and the sample piece transport mechanism controlled by the control device separates and extracts the sample piece from the sample, holds the sample piece and transports it to the sample piece holder.

[0007] The above configuration includes a stage that holds the sample on which the sample piece is formed and the sample piece holder, a stage driving mechanism that moves the stage, an optical system that divides a predetermined light emitted from a light source and irradiates it onto an object to be observed and a reference surface, and combines the reflected light from the object to be observed and the reflected light from the reference surface to form a combined light that indicates an interference state of the two reflected lights, an imaging device that captures an image formed by the optical system and outputs an image signal obtained, and an optical system driving mechanism that moves the optical system relative to the stage so as to change the distance between the optical system and the stage, and the control device may control the sample piece transport mechanism, the stage driving mechanism, and the optical system driving mechanism based on information regarding the processing and the interference state detected in the image output by the imaging device.

[0008] In the above configuration, the control device may detect the position of the object to be observed according to coordinate data indicating the position of the optical system in real space when the intensity or contrast of the interference fringes detected in the image is maximized while moving the optical system by the optical system driving mechanism.

[0009] In the aforementioned configuration, the control device may detect a position of the observation target according to a distribution of the interference fringes.

[0010] In the above configuration, the control device may determine that contact has occurred between the sample piece holding portion of the sample piece transport mechanism or the sample piece held by the sample piece holding portion and the object to be observed when distortion occurs in the interference fringes detected in the image output by the imaging device when the sample piece transport mechanism is driven.

[0011] The above configuration includes a first imaging device which is the imaging device that captures an image formed by the optical system, and a second imaging device which outputs a signal of an image obtained by imaging the object to be observed, and the control device may detect the position of the object to be observed according to position information of a reference mark detected in the image output by the second imaging device. Effect of the Invention

[0012] According to the present invention, by providing a control device that controls the sample piece transport mechanism based on information regarding the processing used to create the sample piece, it is possible to perform a specified transfer operation with high precision while preventing damage to the sample piece. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a configuration diagram of a thin sample observation system including a sample transfer device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view showing a sample and a sample piece in the sample piece transfer device according to the embodiment of the present invention. [Diagram 3] FIG. 2 is a plan view showing a sample piece holder in the sample piece transfer device according to the embodiment of the present invention. [Figure 4] FIG. 2 is a configuration diagram of a sample piece transfer device according to an embodiment of the present invention. [Diagram 5] 1 is a diagram showing a schematic configuration of an optical interference measurement apparatus according to an embodiment of the present invention. [Figure 6] 4 is a flowchart showing the operation of the sample piece transfer device according to the embodiment of the present invention. [Figure 7] 4A to 4C are diagrams showing examples of focus states and interference fringes in a microscope image of a sample and a sample piece of the sample piece transfer device according to the embodiment of the present invention. [Figure 8]11A to 11C are diagrams showing examples of the focus state and interference fringes in a microscope image of a tweezers arm in the sample piece transfer device according to the embodiment of the present invention. [Figure 9] 1A and 1B are diagrams showing examples of the focus state and interference fringes in a microscope image of a tweezers arm and a sample piece in a sample piece transfer device according to an embodiment of the present invention, in which the tweezers arm is approaching the sample piece. [Figure 10] 1A and 1B are diagrams showing examples of the focus state and interference fringes in a microscope image of a tweezers arm and a sample piece in a sample piece transfer device according to an embodiment of the present invention, in which the tweezers arm is holding the sample piece. [Figure 11] FIG. 13 is a diagram showing an example of the focus state and interference fringes in a microscope image of a tweezers arm and a sample piece in a sample piece transfer device according to an embodiment of the present invention, in which the tweezers arm holding the sample piece is retracted from the sample. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, a sample piece transfer device 10 for automatically transferring a sample piece Q according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a thin sample observation system 1 including a sample transfer device 10 according to an embodiment. 1, a sample piece transfer device 10 according to the embodiment is provided, for example, in a thin sample observation system 1. The thin sample observation system 1 includes a plurality of charged particle beam devices 3, a plurality of transmission electron microscopes 5, a recipe information generating device 7, and a plurality of sample piece transfer devices 10.

[0015] The charged particle beam device 3 processes a wafer-shaped sample (such as a sample substrate) S made of a semiconductor such as silicon to form a sample piece Q of a desired thickness suitable for transmission observation by a transmission electron microscope 5. The charged particle beam device 3 includes, for example, a focused ion beam irradiation optical system that irradiates an irradiation target with a focused ion beam, an electron beam irradiation optical system that irradiates an irradiation target with an electron beam, and a gas supply unit that supplies an etching gas or a deposition gas to the irradiation target. The charged particle beam device 3 irradiates the surface of the irradiation target with a focused ion beam while scanning it, thereby imaging the irradiated part, performing various processes by sputtering (such as drilling and trimming), forming a deposition film, and the like.

[0016] The charged particle beam device 3 obtains an image for observing the surface of the irradiation target by irradiating the surface of the irradiation target with a focused ion beam or an electron beam while scanning the surface. The image of the irradiation target is, for example, a SIM image, a SEM image, or an absorbed current image. The SIM image or SEM image is an image based on secondary charged particles (e.g., secondary electrons or secondary ions) generated from the irradiation target by irradiation with the focused ion beam or electron beam. The absorbed current image is an image based on the inflow current of the charged particle beam flowing into the irradiation target (or the absorbed current of the charged particle beam absorbed by the irradiation target).

[0017] The etching gas selectively promotes etching of the target by the focused ion beam depending on the material of the target. The deposition gas forms a deposition film on the surface of the target by depositing metal, insulator, etc. The deposition film is formed by depositing solid components decomposed from the deposition gas supplied from a gas supply unit on the surface of the target upon irradiation with the charged particle beam.

[0018] FIG. 2 is a plan view showing the sample S and the sample piece Q in the sample piece transfer device 10 according to the embodiment. As shown in FIG. 2, the charged particle beam device 3 forms a sample piece Q (sample piece Q before being extracted from the sample S) by irradiating a surface (shaded area) of the sample S with a focused ion beam. The charged particle beam device 3 excavates a processing area H (white area) inside a processing frame F indicating the scanning range of the focused ion beam by sputtering processing using focused ion beam irradiation. The charged particle beam device 3 forms the sample piece Q based on a reference mark (reference point) Ref indicating the position where the sample piece Q is to be formed (i.e., the position to be left without excavation). The reference mark Ref is, for example, a deposition film of a predetermined shape in which a fine hole is formed by irradiation with a focused ion beam. For example, the charged particle beam device 3 grasps the approximate position of the sample piece Q by the deposition film of the reference mark Ref, and performs precise alignment of the sample piece Q by the fine hole of the reference mark Ref.

[0019] The sample piece Q is, for example, etched so that the peripheral parts of the side and bottom sides are cut away and removed, leaving a support part Qa that is connected to the sample S. The sample piece Q is cantilevered to the sample S by the support part Qa. A cut of an appropriate depth is formed in the support part Qa, making it easy to separate the sample piece Q from the sample S. The sample S on which the sample piece Q has been formed is accommodated in a transport and storage container, such as a front-opening integrated pod, and is transferred from the charged particle beam device 3 to the sample piece transfer device 10.

[0020] The transmission electron microscope 5 performs transmission observation of the specimen Q transferred together with the specimen holder P from the specimen transfer device 10 . FIG. 3 is a plan view showing the sample piece holder P in the sample piece transfer device 10 according to the embodiment. 3, the test piece holder P includes, for example, a grid frame P1 in the form of a circular ring plate, and a mesh P2 provided inside the grid frame P1. The test piece holder P may include, for example, a support film (not shown) provided on the mesh P2. The test piece holder P has reference marks Pa (such as a first reference mark Pa1 and a second reference mark Pa2) formed of through holes of suitable shapes, for example. The specimen holder P for holding the specimen Q is, for example, housed in an appropriate container and transferred from the specimen transfer device 10 to the transmission electron microscope 5 .

[0021] The recipe information generation device 7 generates and stores recipe information including, for example, information regarding the production of a sample piece Q using a charged particle beam device 3 (processing recipe), information regarding transmission observation of the sample piece Q using a transmission electron microscope 5 (observation recipe), and information regarding the transfer of the sample piece Q using a sample piece transfer device 10 (transfer recipe). The processing recipe includes information on the steps and conditions for producing a sample piece Q from the sample S. For example, the processing recipe includes information on the position of the sample piece Q based on the coordinates of various processing positions of the charged particle beam device 3, such as the relative position between a reference mark Ref on the sample S and the sample piece Q, and information on the dimensions of the sample piece Q, such as the depth of the processing region H where the sample piece Q is formed. The transfer recipe includes information on the process and conditions for transferring the sample piece Q from the sample S to the sample piece holder P. For example, the transfer recipe includes identification information of a container for accommodating the sample S, identification information of the sample S, information on the success or failure of the preparation of the sample piece Q, information on the relative relationship of the coordinates of each stage of the charged particle beam device 3 and the sample piece transfer device 10, information on the relative relationship of the coordinates of a stage 31a of a sample stage 31 described later and a pair of arms 81a of tweezers 81 of the sample piece transport device 13, information on the position and dimensions of the sample piece Q in the processing recipe, identification information of the sample piece holder P, and information on the mounting position of the sample piece Q on the sample piece holder P. The observation recipe includes information on the process and conditions of transmission observation of the specimen piece Q. For example, the observation recipe includes identification information of a container that contains the specimen piece holder P, identification information of the specimen piece holder P, information on the mounting position and posture (front and back) of the specimen piece Q on the specimen piece holder P, and information on the relative relationship between the coordinates of each stage of the transmission electron microscope 5 and the specimen piece transfer device 10.

[0022] The recipe information generating device 7 stores, for example, image data obtained from each of the charged particle beam device 3 and the sample piece transfer device 10 together with recipe information. The image data from the charged particle beam device 3 is, for example, an image for observation (i.e., an SIM image or an SEM image) obtained by scanning and irradiating a focused ion beam or an electron beam onto an appropriate region including the sample S after the preparation of the sample piece Q in the sample S is completed. The image data from the sample piece transfer device 10 is, for example, a microscope image of the sample piece Q attached to the sample piece holder P.

[0023] Fig. 4 is a configuration diagram of a sample piece transfer device 10 according to an embodiment. Fig. 5 is a diagram showing a schematic configuration of an optical interference measuring device 11 according to an embodiment. 4, the sample piece transfer device 10 includes, for example, an optical interference measuring device 11, a sample piece transport device 13, a load port 15, a sample transport device 17, and a sample piece holder transport device 19. The sample piece transfer device 10 includes a control device 21 that controls the overall operation of the sample piece transfer device 10, and an input device 23 and a display device 25 that are connected to the control device 21.

[0024] In the following description, the X-axis, Y-axis, and Z-axis directions, which are mutually orthogonal in a three-dimensional space, are parallel to each other. For example, the Z-axis direction is parallel to the up-down direction (e.g., vertical direction) of the sample piece transfer device 10. The X-axis and Y-axis directions are parallel to a reference plane (e.g., horizontal plane) that is perpendicular to the up-down direction of the sample piece transfer device 10.

[0025] The optical interference measurement device 11 is, for example, a linique-type white light interference microscope. The optical interference measurement device 11 includes, for example, a sample stage 31, a lens barrel 33, and a lens barrel driving mechanism . The sample stage 31 includes a stage 31a that supports the sample S, and a stage driving mechanism 31b that two-dimensionally translates and rotates the stage 31a. The stage driving mechanism 31b translates the stage 31a, for example, along each of the X-axis and Y-axis directions. The stage driving mechanism 31b may also include a mechanism for translating the stage 31a along the Z-axis direction. The stage driving mechanism 31b rotates the stage 31a, for example, at an appropriate angle around each of a predetermined rotation axis and tilt axis. The rotation axis is set relative to the stage 31a, and is parallel to the up-down direction of the sample piece transfer device 10 when the stage 31a is at a predetermined reference position around the tilt axis. The tilt axis is parallel to a direction perpendicular to the up-down direction of the sample piece transfer device 10. The stage driving mechanism 31b is controlled by a control signal output from the control device 21 according to the operation mode of the sample piece transfer device 10, etc.

[0026] 4 and 5, the lens barrel 33 includes, for example, a light source lens barrel 41 and an observation lens barrel 43 which are integrally connected perpendicular to each other. For example, the light source lens barrel 41 extends along the X-axis direction, and the observation lens barrel 43 extends along the Z-axis direction. The light source barrel 41 includes, for example, a light source 51 and a filter 53. The light source 51 is, for example, a white light source. The filter 53 is, for example, a wavelength filter such as a bandpass filter, a polarizing filter, or the like. The observation lens barrel 43 includes, for example, a first beam splitter 61 and a second beam splitter 63, a first objective lens 65 and a second objective lens 67, a reflecting mirror 69, an imaging lens 71, an observation camera 73, and a position adjustment camera 75.

[0027] The first beam splitter 61 is disposed at a connection between the light source tube 41 and the observation tube 43, such as at a position where the central axes of the light source tube 41 and the observation tube 43 intersect. The first beam splitter 61 reflects the illumination light L0 traveling from the light source 51 through the filter 53 toward a first end 43a of the observation tube 43 that is closer to the object to be observed (i.e., toward a first objective lens 65, which will be described later). The first beam splitter 61 causes reflected light L1, L2 (combined light) from a second beam splitter 63 described below to travel toward a second end 43b, one of the ends of the observation lens barrel 43, which is closer to the observation camera 73.

[0028] The second beam splitter 63 is disposed between the first beam splitter 61 and the first objective lens 65. The second beam splitter 63 splits the illumination light L0 from the first beam splitter 61 into a first direction along the central axis of the observation lens barrel 43 and a second direction perpendicular to the central axis of the observation lens barrel 43. The first direction is, for example, the Z-axis direction, which is the direction toward the first objective lens 65 described later. The second direction is, for example, the X-axis direction, which is the direction toward the second objective lens 67 described later. The second beam splitter 63 causes a composite light obtained by superimposing reflected light L1 from an observation object (described later) and reflected light L2 from a reflecting mirror 69 to travel toward the second end 43b of the observation lens barrel 43. The interference state of the composite light changes according to the optical path difference between the reflected light L1 from the observation object and the reflected light L2 from the reflecting mirror 69.

[0029] The first objective lens 65 is disposed at the first end 43a of the observation lens barrel 43. The first objective lens 65 focuses the illumination light L0 traveling (transmitting) from the second beam splitter 63 along the first direction onto an observation target (for example, the sample S, the sample piece Q, and a pair of arms 81a of tweezers 81 described later). The second objective lens 67 is disposed at an appropriate distance in the second direction from the second beam splitter 63. The second objective lens 67 focuses the illumination light L0 traveling (reflected) from the second beam splitter 63 in the second direction onto a reflecting mirror 69. The reflecting mirror 69 is disposed at an appropriate distance from the second objective lens 67 along the second direction. The reflecting mirror 69 has a reference surface 69A, which is a surface that is smoothly formed with a predetermined accuracy. The reflecting mirror 69 reflects the illumination light L0 from the second objective lens 67 toward the second beam splitter 63 by the reference surface 69A.

[0030] The imaging lens 71 is disposed between the first beam splitter 61 and the observation camera 73. The imaging lens 71 forms an image of the interference fringes by focusing the combined light from the first beam splitter 61. The observation camera 73 is disposed at the second end 43b of the observation lens barrel 43. The observation camera 73 captures an interference fringe of the combined light formed by the imaging lens 71, and outputs a signal of the image (microscope image) obtained by capturing the image. The position adjustment camera 75 captures an image of the sample S and the sample piece holder P arranged on the stage 31a, for example, and outputs a signal of the image obtained by capturing the image.

[0031] The lens barrel driving mechanism 35 changes the distance in the Z-axis direction between the sample stage 31 and the lens barrel 33 (i.e., the relative position in the Z-axis direction of the first objective lens 65 with respect to the observation target) by, for example, translating the lens barrel 33 along the Z-axis direction. The lens barrel driving mechanism 35 includes, for example, a motor 35a for coarse adjustment and a piezo actuator 35b for fine adjustment.

[0032] The optical interference measuring device 11 obtains information on the position and three-dimensional shape of the object in real space by two-beam interference using white light. The optical path difference between the reflected light L1 from the object and the reflected light L2 from the reflecting mirror 69, which are combined by the second beam splitter 63, changes the interference state of the combined light obtained by combining the two reflected lights L1 and L2. The combined light generates interference fringes of bright and dark images in which the reflected light L1 from the object and the reflected light L2 from the reflecting mirror 69 are constructive (bright) when their phases match, and destructive (darker) when their phases do not match. Since the reference surface 69A of the reflecting mirror 69 is smoothly formed, the interference fringes indicate information on the three-dimensional shape of the object, such as the unevenness of the surface. The interval between the interference fringes indicates a constant optical path difference depending on the wavelength of the irradiated light L0 from the light source 51, so the distribution of the interference fringes (for example, the number of interference fringes) corresponds to the height difference on the surface of the object. In the optical interference measurement device 11, the relative position between the second objective lens 67 and the reflecting mirror 69 is fixed, whereas the relative position between the first objective lens 65 and the observation target is changed by driving the lens barrel driving mechanism 35. The first objective lens 65 is displaced in the Z-axis direction by driving the lens barrel driving mechanism 35, thereby adjusting the focus position of the observation target (i.e., the position where the intensity or contrast of the interference fringes observed in the microscope image is maximized). The position of the focus position of the observation target in the Z-axis direction (Z position) is associated with coordinate data (Z-axis coordinate) indicating the position of the first objective lens 65 (or lens barrel 33) in real space.

[0033] The sample piece transport device 13 includes, for example, tweezers 81 serving as a sample piece holder, and a tweezers drive mechanism 83. The tweezers 81 grip the sample piece Q by sandwiching it from both sides in the thickness direction with a pair of arms 81a. The pair of arms 81a of the tweezers 81 extract the sample piece Q from the sample S and transfer the sample piece Q to the sample piece holder P. Note that the sample piece holder is not limited to the tweezers 81, and may be, for example, a glass or metal probe. For example, the probe adsorbs the sample piece Q by electrostatic force or the like. The tweezers driving mechanism 83 three-dimensionally displaces the tweezers 81 with respect to the stage 31a of the optical interference measurement device 11, and opens and closes the pair of arms 81a. For example, the tweezers driving mechanism 83 translates the pair of arms 81a of the tweezers 81 in the X-axis, Y-axis, and Z-axis directions while tilting the pair of arms 81a of the tweezers 81 within a predetermined angle range with respect to the surface of the stage 31a. The tweezers driving mechanism 83 may rotate the pair of arms 81a of the tweezers 81 around an appropriate rotation axis.

[0034] The load port 15 supports a container for accommodating a sample S, such as a front-opening integrated pod, and exposes the sample S inside the container by opening the lid of the container. The sample transport device 17 is, for example, a robot for transporting the sample S. The sample transport device 17 transports the sample S between a container supported by the load port 15 and a predetermined position on the stage 31a (for example, a central position intersecting with the central axis of the observation lens barrel 43). The sample transport device 17 takes out the sample S from the container supported by the load port 15 and places the sample S at a predetermined position on the stage 31a. The sample piece holder transport device 19 is, for example, a transport robot for the sample piece holder P. The sample piece holder transport device 19 transports the sample piece holder P between a transport container arranged on a support portion (not shown) and a predetermined position on the stage 31a. The sample piece holder transport device 19 takes out the sample piece holder P from the transport container arranged on the support portion and places the sample piece holder P at a predetermined position on the stage 31a.

[0035] The control device 21 comprehensively controls the operation of the sample piece transfer device 10, for example, by a signal output from the input device 23 or a signal generated by a preset automatic operation control process. The control device 21 is a software function unit that functions by a processor such as a CPU (Central Processing Unit) executing a predetermined program. The software function unit is an ECU (Electronic Control Unit) that includes a processor such as a CPU, a ROM (Read Only Memory) that stores programs, a RAM (Random Access Memory) that temporarily stores data, and electronic circuits such as a timer. At least a part of the control device 21 may be an integrated circuit such as an LSI (Large Scale Integration).

[0036] The control device 21 transfers the sample piece Q from the sample S to the sample piece holder P in accordance with recipe information (e.g., a transfer recipe based on a processing recipe) acquired from the recipe information generating device 7. The control device 21 transmits information such as the mounting position and attitude of the sample piece Q on the sample piece holder P to the recipe information generating device 7 so as to add it to the recipe information.

[0037] The input device 23 is, for example, a mouse and a keyboard that output signals according to input operations by an operator. The display device 25 displays various information about the sample piece transfer device 10, image data generated from signals output from each camera 73, 75, and a screen for performing operations such as enlarging, reducing, moving, and rotating the image data.

[0038] The sample piece transfer device 10 according to an embodiment of the present invention has the above-mentioned configuration. Next, the operation of this sample piece transfer device 10, i.e., the operation of automatically transferring the sample piece Q formed by processing the sample S with the charged particle beam (focused ion beam) of the charged particle beam device 3 to the sample piece holder P, will be described.

[0039] FIG. 6 is a flowchart showing the operation of the sample piece transfer device 10 according to the embodiment. As shown in FIG. 6, first, the control device 21 recognizes a desired sample S based on the identification information of a container supported by the load port 15 and the position of each of at least one sample S contained in the container (step S01). Next, the control device 21 acquires recipe information corresponding to the recognized sample S from the recipe information generating device 7 (step S02). Next, the control device 21 causes the sample transport device 17 to take out the sample S from the container of the load port 15 and place it at a predetermined position on the stage 31a (step S03).

[0040] Next, the control device 21 reads the identification information of each of the containers placed on the support portion of the sample piece holder transport device 19 and the sample piece holders P contained in the containers, and obtains information such as the shape of the sample piece holders P and the reference mark Pa (step S04). Next, the control device 21 causes the sample piece holder transport device 19 to take out the sample piece holder P from the container of the support portion and place it at a predetermined position on the stage 31a (step S05).

[0041] Next, the control device 21 obtains an image signal obtained by capturing an image of the sample S placed on the stage 31a from the position adjustment camera 75. The control device 21 detects the position of a notch (not shown) for positioning the crystal orientation formed in the sample S from the captured image of the sample S, and detects an offset amount and a rotation angle of the sample S with respect to a predetermined attitude based on the position of the notch. The control device 21 drives the stage 31a by the stage driving mechanism 31b so as to correct the detected offset amount and rotation angle of the sample S and set the sample S to the predetermined attitude (step S06). Here, the position adjustment camera 75 may be used to detect an alignment mark of the sample S, and the sample S may be set to the predetermined attitude based on the detection result.

[0042] Next, the control device 21 obtains an image signal obtained by imaging the sample piece holder P placed on the stage 31a from the position adjustment camera 75. The control device 21 detects the position of the reference mark Pa formed on the sample piece holder P from the captured image of the sample piece holder P, and detects the rotation angle of the sample piece holder P with respect to a predetermined attitude. Based on the detected position of the reference mark Pa, the control device 21 associates the attachment position of the sample piece Q on the sample piece holder P with the coordinate information of the stage 31a (step S07).

[0043] Next, the control device 21 drives the stage 31a by the stage driving mechanism 31b so that the position of the target sample piece Q is brought into the field of view of the observation camera 73 and coincides with a predetermined lift-out position based on the coordinates of various processing positions of the charged particle beam device 3 in the processing recipe (step S08). For example, the control device 21 may specify the charged particle beam device 3 used to fabricate the desired sample piece Q based on the processing recipe, and set parameters to correct the correspondence relationship between the stage coordinates of the specified charged particle beam device 3 and the sample piece transfer device 10.

[0044] Next, the control device 21 acquires a signal of a microscope image of a processing mark formed on the sample S by the charged particle beam device 3 from the observation camera 73. The processing mark on the sample S is, for example, an area including the inside of the processing frame F on the sample S and the reference mark Ref (see FIG. 2). The control device 21 drives the stage 31a by the stage driving mechanism 31b based on image data (for example, a SIM image or SEM image) of the processing mark on the sample S acquired from the recipe information generating device 7 and the microscope image acquired from the observation camera 73 so that the processing mark on the sample S coincides with the center of the field of view of the field of view of the observation camera 73 (step S09). For example, the control device 21 uses the image data acquired from the recipe information generating device 7 as a template (reference image data) and executes template matching (such as superimposing the template and the microscope image) on the microscope image acquired from the observation camera 73 to coincide with the processing mark on the sample S with the center of the field of view.

[0045] Next, the control device 21 recognizes the position of the sample piece Q from the relative positional relationship between the reference mark Ref, which is known from the recipe information, and the sample piece Q based on the microscope image of the processing marks on the sample S. The control device 21 sets the approach position of the pair of arms 81a of the tweezers 81 according to the recognized position of the sample piece Q (step S10). The approach position of the pair of arms 81a is, for example, a target position of the tip of the pair of arms 81a specified by the X-axis coordinate and the Y-axis coordinate, and is a position where the tip of the pair of arms 81a starts to approach the sample piece Q in the Z-axis direction.

[0046] Next, the control device 21 measures the position in the Z axis direction (Z position) of the sample piece Q based on the signal of the microscope image output from the observation camera 73 while moving the microscope tube 33 in the Z axis direction by the microscope tube driving mechanism 35 (step S11). For example, the control device 21 grasps the Z position of the sample piece Q based on the Z axis coordinate of the microscope tube 33 when the surface of the sample piece Q is in focus (i.e., when the intensity or contrast of the interference fringes observed in the microscope image is maximum, etc.). FIG. 7 is a diagram showing an example of the focus state and interference fringes Fa in a microscope image of the sample S and the sample Q of the sample piece transfer device 10 according to the embodiment. As shown in FIG. 7, the control device 21 moves the lens barrel 33 in the Z-axis direction to transition from a state in which the surfaces of the sample S and the sample piece Q are not in focus to a state in which the surfaces of the sample S and the sample piece Q are in focus. For example, the control device 21 grasps the Z position of the sample piece Q based on the Z-axis coordinate (=predetermined value Za) when the state transitions from a state in which the interference fringes Fa are not observed or are not clear because the Z-axis coordinate of the lens barrel 33 is greater than a predetermined value Za to a state in which the interference fringes Fa are observed more clearly. Furthermore, the control device 21 may grasp the Z position of the sample piece Q in more detail from the number of interference fringes Fa observed on the surfaces of the sample S and the sample piece Q based on the fact that the interval between the interference fringes Fa depends on the wavelength of the light irradiated from the light source 51 and the distribution of the interference fringes Fa (for example, the number of interference fringes Fa, etc.) corresponds to the height difference of the surface of the observation target.

[0047] Next, the control device 21 moves the tips of the pair of arms 81a of the tweezers 81 upward in the Z-axis direction of the sample piece Q by the tweezers driving mechanism 83 in accordance with the approach position set in the above-mentioned step S10 (step S12). Next, the control device 21 grasps the position of the tip of the pair of arms 81a of the tweezers 81 based on the signal of the microscope image output from the observation camera 73 (step S13). The position of the tip of the pair of arms 81a is a position specified by, for example, X-axis coordinates and Y-axis coordinates. For example, the control device 21 moves the lens barrel 33 in the Z-axis direction by the lens barrel driving mechanism 35, and grasps the relative positional relationship with the center of the field of view when the tips of the pair of arms 81a are in focus (i.e., when the intensity or contrast of the interference fringes observed in the microscope image is maximum, etc.) by the X-axis coordinates and the Y-axis coordinates.

[0048] Next, while moving the lens barrel 33 in the Z-axis direction by the lens barrel driving mechanism 35, the control device 21 measures the position in the Z-axis direction (Z position) of the tips of the pair of arms 81a of the tweezers 81 based on the signal of the microscope image output from the observation camera 73 (step S14). The control device 21 grasps the Z position of the tips of the pair of arms 81a based on, for example, interference fringes observed on the pair of arms 81a in the microscope image. FIG. 8 is a diagram showing an example of the focus state and interference fringes Fb in a microscope image of a pair of arms 81a of the tweezers 81 of the sample piece transfer device 10 according to the embodiment. 8, the control device 21 transitions from a state in which the surfaces of the tips of the pair of arms 81a are not in focus to a state in which the surfaces of the tips of the pair of arms 81a are in focus by moving the lens barrel 33 in the Z-axis direction. For example, the control device 21 grasps the Z position of the tips of the pair of arms 81a based on the Z-axis coordinate (=predetermined value Zb) when the state transitions from a state in which the interference fringes Fb are not observed or are not clear because the Z-axis coordinate is larger than a predetermined value Zb, or a state in which the interference fringes Fb are observed other than the tips of the pair of arms 81a (such as the center) because the Z-axis coordinate is smaller than the predetermined value Zb, to a state in which the interference fringes Fb are observed more clearly at the tips of the pair of arms 81a. Furthermore, the control device 21 may grasp the Z position of the tips of the pair of arms 81a in more detail according to the number of interference fringes Fb observed on the surface of the tips of the pair of arms 81a, based on the fact that the spacing between the interference fringes Fb depends on the wavelength of the light irradiated from the light source 51 and the distribution of the interference fringes Fb (e.g., the number of interference fringes Fb) corresponds to the difference in elevation on the surface of the object to be observed. Furthermore, the control device 21 may grasp the Z position of the tips of the pair of arms 81a in more detail based on the known shapes and dimensions of the tips of the pair of arms 81a.

[0049] Next, based on the difference between the approach position set in the above-mentioned step S10 and the position of the tips of the pair of arms 81a of the tweezers 81 grasped in the above-mentioned step S13, the control device 21 moves the pair of arms 81a by the tweezers driving mechanism 83 so as to match the position of the tips of the pair of arms 81a with the approach position (i.e., to eliminate the positional difference) (step S15).

[0050] Next, the control device 21 moves the pair of arms 81a to a holding position in the Z-axis direction by the tweezers driving mechanism 83 based on the Z position of the sample piece Q grasped in the above-mentioned step S11, the Z position of the tips of the pair of arms 81a of the tweezers 81 grasped in the above-mentioned step S14, information on the shape and size of the sample piece Q known from the recipe information, and information on the shape and size of the tips of the pair of arms 81a known from a previous measurement or the like (step S16). The holding position is, for example, a position where the tips of the pair of arms 81a come into contact with the sample piece Q and the sample piece Q can be held by the movement of the pair of arms 81a from open to closed. Figure 9 is a diagram showing the focus state and an example of interference fringes Fc1, Fc2 in a microscope image of a pair of arms 81a of tweezers 81 of the sample piece transfer device 10 of the embodiment, and shows the state in which the pair of arms 81a approach the sample piece Q. As shown in Figure 9, the control device 21 gradually moves the pair of arms 81a of the tweezers 81, which are in an open state where interference fringes Fc1 are observed by focusing on the surfaces of the sample S and the sample piece Q, in the Z-axis direction, until interference fringes Fc2 are observed at the tips of the pair of arms 81a and the sample piece Q can be held by the tips of the pair of arms 81a. In addition, the control device 21 may determine that the tips of the pair of arms 81a have come into contact with the sample piece Q, for example, when distortion occurs in the interference fringes on the surface of the sample piece Q detected in the microscope image output from the observation camera 73.

[0051] Next, the control device 21 holds the sample piece Q by the tips of the pair of arms 81a of the tweezers 81, and separates the sample piece Q from the sample S (step S17). The control device 21 checks whether the sample piece Q is being held by the tips of the pair of arms 81a, for example, by performing a predetermined image recognition process on the microscope image output from the observation camera 73. Figure 10 is a diagram showing the focus state and an example of interference fringes Fc1, Fc2 in a microscope image of a pair of arms 81a of tweezers 81 of the sample piece transfer device 10 of the embodiment, and shows the state in which the pair of arms 81a are holding a sample piece Q. 10, the control device 21 pinches and holds the sample piece Q from both sides in the thickness direction with the tips of the pair of arms 81a in a state in which interference fringes Fc1, Fc2 are observed by focusing on the surfaces of the sample S and the sample piece Q and the tips of the pair of arms 81a of the tweezers 81. The control device 21 displaces the pair of arms 81a holding the sample piece Q in an appropriate direction (for example, the thickness direction of the sample piece Q, etc.) to release the support of the sample piece Q by the support part Qa of the sample S (see FIG. 2) and separate the sample piece Q from the sample S.

[0052] Next, the control device 21 causes the tweezers driving mechanism 83 to raise the pair of arms 81a of the tweezers 81 upward in the Z-axis direction, thereby retracting the pair of arms 81a from the sample S (step S18). Figure 11 is a diagram showing the focus state and an example of interference fringes Fc2 in a microscope image of a pair of arms 81a of tweezers 81 of a sample piece transfer device 10 according to an embodiment, illustrating the state in which the pair of arms 81a holding the sample piece Q are retracted from the sample S. As shown in Figure 11, the control device 21, for example, retracts the pair of arms 81a holding the sample piece Q from the sample S while maintaining focus at the tips of the pair of arms 81a of the tweezers 81 so that interference fringes Fc2 can be observed.

[0053] Next, the control device 21 drives the stage 31a by the stage driving mechanism 31b so that the mounting position of the sample piece Q in the sample piece holder P coincides with the center of the field of view of the viewing area of ​​the observation camera 73 (step S19). First, the control device 21 moves the stage 31a based on the mounting position of the sample piece Q in the sample piece holder P associated in the above-mentioned step 07 and the coordinate information of the stage 31a. Next, the control device 21 moves the stage 31a based on predetermined reference image data (e.g., a predetermined template) indicating the mounting position of the sample piece Q in the sample piece holder P and a microscope image of the sample piece holder P acquired from the observation camera 73. The control device 21 matches the mounting position of the sample piece Q in the sample piece holder P with the center of the field of view of the viewing area of ​​the observation camera 73, for example, by template matching between the predetermined template and the microscope image. Here, instead of template matching, an edge may be detected at a position offset from the mounting position of the sample piece Q, and the mounting position may be derived based on the extracted edge position. This is effective when the field of view required for template matching cannot be obtained.

[0054] Next, based on the positions of the tips of the pair of arms 81a of the tweezers 81 grasped in the above-mentioned step S13, the control device 21 moves the pair of arms 81a using the tweezers driving mechanism 83 so that the positions of the tips of the pair of arms 81a coincide with the center of the field of view of the observation camera 73 (step S20).

[0055] Next, while moving the microscope barrel 33 in the Z-axis direction using the microscope barrel driving mechanism 35, the control device 21 measures whether or not the tip of the pair of arms 81a of the tweezers 81 or the sample piece Q held at the tip of the pair of arms 81a is in contact with the attachment position of the sample piece Q in the sample piece holder P based on the signal of the microscope image output from the observation camera 73 (step S21). For example, when distortion occurs in the interference fringes of the sample piece holder P detected in the microscope image output from the observation camera 73, the control device 21 determines that the sample piece Q held at the tip of the pair of arms 81a or the tip of the pair of arms 81a is in contact with the sample piece holder P.

[0056] Next, after the tips of the pair of arms 81a of the tweezers 81 or the sample piece Q comes into contact with the attachment position of the sample piece Q on the sample piece holder P, the control device 21 releases the hold of the sample piece Q by closing and opening the pair of arms 81a, and attaches the sample piece Q to the sample piece holder P (step S22). Next, the control device 21 adds information such as the microscope image of the sample piece holder P after the sample piece Q is attached, the attachment position and attachment posture of the sample piece Q on the sample piece holder P, etc. to the recipe information of the recipe information generating device 7 (step S23).

[0057] Next, the control device 21 judges whether or not the next sample piece Q is to be taken out from the sample S. If the result of this determination is "YES", the control device 21 returns the process to step S08 described above. On the other hand, if the result of this determination is "NO", the control device 21 advances the process to step S25.

[0058] Next, the control device 21 moves the pair of arms 81a of the tweezers 81 to a predetermined reference position by the tweezers driving mechanism 83 (step S25). Then, the control device 21 advances the process to the end. With the above, a series of automatic operations for transferring the sample piece Q is completed. The above-mentioned flow from start to end is only an example, and steps may be replaced or skipped as appropriate as long as it does not interfere with the overall flow. The control device 21 can perform the relocation operation unmanned by continuously operating the above-mentioned from start to end.

[0059] As described above, the sample piece transfer device 10 of the embodiment is equipped with a control device 21 that controls the sample piece transport device 13 based on information (processing recipe) regarding processing to produce the sample piece Q by the charged particle beam device 3, thereby enabling the sample piece Q to be accurately transferred while preventing damage to the sample piece Q. By providing a control device 21 that controls the stage driving mechanism 31b, the lens barrel driving mechanism 35, and the tweezers driving mechanism 83 based on interference fringes detected in an image output from the observation camera 73 provided in the lens barrel 33, which is a so-called two-beam interference optical system, it is possible to accurately extract the sample piece Q from the sample S using a pair of arms 81a of the tweezers 81 and transport the sample piece Q to the sample piece holder P.

[0060] By providing a control device 21 that detects the Z position of the observation object (e.g., sample S, sample piece Q, sample piece holder P, and a pair of arms 81a of tweezers 81, etc.) based on the intensity, contrast, or distribution of interference fringes detected in the image of the observation object output from the observation camera 73, the Z position can be detected with high accuracy even for observation objects having a shape, structure, or size (area, etc.) that makes it difficult to confirm whether or not they are in focus.

[0061] By providing a control device 21 that detects the position of the object to be observed (e.g., X-axis coordinate and Y-axis coordinate) based on a reference mark (e.g., a notch in the sample S and a reference mark Pa in the sample piece holder P) detected in an image of the object to be observed output from the position adjustment camera 75, the position of the object to be observed can be detected with high accuracy even in cases where it is difficult to detect the position using a microscope image.

[0062] When a distortion occurs in the interference fringes detected in the image of the object to be observed output from the observation camera 73 due to the extraction of a sample piece Q from a sample S using the pair of arms 81a of the tweezers 81 and the placement of the sample piece Q on a sample piece holder P using the pair of arms 81a, the presence or absence of contact can be accurately detected by providing a control device 21 that determines that the pair of arms 81a or the sample piece Q held by the pair of arms 81a has come into contact with the object to be observed.

[0063] (Modification) Modifications of the embodiment will be described below. Note that the same parts as those in the above-described embodiment will be denoted by the same reference numerals and descriptions thereof will be omitted or simplified.

[0064] In the above-described embodiment, the optical interference measuring device 11 is equipped with Linnek interference type objective lenses (first objective lens 65 and second objective lens 67), but is not limited to this and may be equipped with other interference objective lenses, such as a Michelson interference type or a Mirau interference type.

[0065] In the above-described embodiment, the control device 21 performs template matching when aligning the processing marks on the sample S with the center of the field of view and when aligning the mounting position of the sample piece Q in the sample piece holder P with the center of the field of view, but this is not limited to this and other image recognition processes may be performed.

[0066] In the above embodiment, the charged particle beam device 3 includes an electron beam column and a focused ion beam column, but is not limited thereto. For example, the charged particle beam device 3 may include only a focused ion beam column without including an electron beam column.

[0067] In the above embodiment, the outer shape of the sample piece holder P is a disk shape, but this is not limited thereto and may be other shapes. For example, the outer shape of the sample piece holder P may be a disk shape with a part of it omitted, a semicircular plate shape, or the like. For example, the sample piece holder P may include a plurality of comb-teeth-shaped columnar parts.

[0068] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as the scope and spirit of the invention. [Explanation of symbols]

[0069] 1...Thin sample observation system, 3...Charged particle beam device, 5...Transmission electron microscope, 7...Recipe information generation device, 10...Sample piece transfer device, 11...Optical interference measurement device, 13...Sample piece transport device (sample piece transport mechanism), 15...Load port, 17...Sample transport device, 19...Sample piece holder transport device, 21...Control device, 23...Input device, 25...Display device, 31...Sample stage, 31a...Stage, 31b...Stage drive mechanism, 33...lens barrel (optical system), 35...lens barrel drive mechanism (optical system drive mechanism), 69A...reference surface, 73...observation camera (imaging device, first imaging device), 75...position adjustment camera (second imaging device), 81...tweezers (sample piece holding part), Fa, Fb, Fc1, Fc2...interference fringes, S...sample (object of observation), Q...sample piece (object of observation), P...sample piece holder (object of observation), Pa...reference mark, Ref...reference mark.

Claims

1. a sample piece transport mechanism for transporting the sample piece from a sample on which the sample piece is formed to a sample piece holder; a control device for controlling the sample piece transport mechanism based on information regarding processing for producing the sample piece by irradiating the sample with a charged particle beam using a charged particle beam device; The sample piece transfer device, characterized in that the sample piece transport mechanism controlled by the control device separates and extracts the sample piece from the sample, and holds the sample piece and transports it to the sample piece holder.

2. a stage for holding the sample on which the sample piece is formed and the sample piece holder; a stage driving mechanism for moving the stage; an optical system that splits a predetermined light emitted from a light source and irradiates the split light onto an observation target and a reference surface, and combines the light reflected from the observation target and the light reflected from the reference surface to form an image of combined light that indicates an interference state of the two reflected lights; an imaging device that captures an image formed by the optical system and outputs an image signal obtained by the imaging device; an optical system driving mechanism that moves the optical system relative to the stage so as to change a distance between the optical system and the stage; Equipped with the control device controls the sample piece transport mechanism, the stage drive mechanism, and the optical system drive mechanism based on information related to the processing and the interference state detected in the image output by the imaging device.

2. The sample piece transfer device according to claim 1 .

3. The control device includes: detecting a position of the object to be observed according to coordinate data indicating a position of the optical system in real space when an intensity or contrast of an interference fringe detected in the image is maximized while moving the optical system by the optical system driving mechanism; 3. The sample piece transfer device according to claim 2.

4. The control device includes:

4. The sample piece transfer device according to claim 3, wherein the position of the observation target is detected according to a distribution of the interference fringes.

5. The control device includes: A sample piece transfer device as described in claim 3 or claim 4, characterized in that if distortion occurs in the interference fringes detected in the image output by the imaging device when the sample piece transport mechanism is driven, it is determined that the sample piece holding part of the sample piece transport mechanism or the sample piece held by the sample piece holding part has come into contact with the object to be observed.

6. a first imaging device which is the imaging device that captures an image formed by the optical system; a second imaging device that outputs a signal of an image obtained by imaging the observation target, The control device includes: detecting a position of the observation target according to position information of a reference mark detected in the image output by the second imaging device; 6. The sample piece transfer device according to claim 2, wherein the sample piece is arranged in a substantially rectangular shape.

Images